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1. ge E E 22 s My Mh Moy Me Mi ag 1l 43 09 ke ke de sS My mM My Mp a a9 7 According to the Routh Hurwitz stability criterion the sys tem is asymptotically stable iff ay 4 gt 0 agag gt azar and a3a2a gt a4a azag Since all spring and damping as Pos Att Ui Ts JAV l Fig 3 Complete haptic teleoperation loop coefficients are strictly positive the first condition is always fulfilled Furthermore it can be shown that any choice of the parameters satisfies the second inequality Thus the stability of the subsystem boils down to the following condition 2 2 434941 gt 4401 4349 8 Note that in the sliding mode the movement of the haptic device has no influence on the desired trajectory It is trivial to see that this trajectory generation is in this mode asymptotically stable consider e g Eq 3 For the characteristic polynomial of the master controller in the sliding mode holds det s A s gt Z i 9 Mh Since 6 and mp are stricly positive the master controller stays stable also in the sliding mode Furthermore if the operator switches back to the direct mode the haptic device is seen to be virtually shifted to the virtual mass Thus the user s inputs are directly mapped with respect to the new initial position Hence the proposed haptic teleoperation algorithm does not introduce any instabilities into the flight2. chanics 28 6 733 737 1995 Force Dimension Omega 6 http www forcedimension com Force Dimension User Manual Omega x Haptic Device version 1 4 Futaba Instruction Manual for Futaba 7C 2 4GHz http www futaba rc com faq 7c faq html MathWorks MATLAB Simulink http www mathworks com PTI PhoeniX VisualEyez VZ4000 http www ptiphoenix com PTI PhoeniX VisualEyez User Manual version 3 6 C Roos C Hiierzeler and S Bouabdallah Design of a Collision Tolerant Airframe for Quadrotors ASL ETH Zurich 2009 Semester Thesis ROS Robot Operating System http www ros org A Riiesch C Hiierzeler and J Nikolic Dynamicas Identification amp Validation and Position Control for a Quadrotor ASL ETH Zurich 2010 Semester Thesis Sitecom wireless gigabit router 300N http www sitecom com August 26 2011
3. Marker Data R 2 9 2 6 9 Y 9 2m lt FS 70m 3D View of Capture Area 3DTracker System UAV LED Markers Fig 6 Overview of the experimental set up E la i eae 5 hy VA y INA AA WI S Ul IA pos ref no 2 pos UAV 140 time sec a lt a 0 2 5 gt Dro tr dl id ra da a lt 5 le os UAV e 0 1t l u pos 90 100 110 120 130 140 time sec E T T T T T T pos ref 0 8 gt pos UAV n 0 6 rool i bod S 04 na VAN o 0 2 gt u o L1 90 100 110 120 130 140 time sec 5E AR Mi e A E SEN ceed eatery eae EE EEEE A TT se eee T ET t E E oO W 5 W h oa S PR W l f D 1 3 force x SED Pett aa A A A P Nes a eta of OM testicals ie akon E r 90 100 110 120 130 oa I time sec force z 5 p DE O rc ere a E utton
4. and 2 that in the Fig 2 Illustration of the core idea 1D sliding mode for the position of the virtual mass holds a a e7 with d ae 3 d My where vg denotes the initial velocity 1 e the velocity just before the virtual mass was decoupled As shown in Eq 3 the human operator can directly influence the direction and amount of the sliding with his motion before switching to the sliding mode i e decoupling the virtual mass i e the faster the user moves the haptic device the further will the virtual mass slide in contrary the virtual mass does not slide if the initial velocity is zero As can be seen in Eq 1 3 the parameters ke Mm and d influence the mapping of the haptic inputs to the reference position The stiffness of the spring ke has to be high enough to ensure a high performance in the direct mode Since the mass m and viscous damping coefficient d are also present in the sliding mode they can be used to tune the sensitivity and amount of the sliding furthermore the viscosity is responsible to avoid overshoots in the direct mode Eventually the position of the virtual mass x is propor tionally mapped to the reference position of the slave device x according to 2 p To 4 S where K represents the scaling factor B Force Feedback As stated in Sec II the master controller provides the human operator with a force feedback which allows the operator to feel the slave s reactio
5. European Commission s Seventh Framework Programme as part of the project AlRobots under grant no 248669 A Ruesch is with the Autonomous Systems Lab Eidgen ssische Technische Hochschule Z rich Switzerland Email arueesch ethz ch A Y Mersha S Stramigioli and R Carloni are with the Fac ulty of Electrical Engineering Mathematics and Computer Science Uni versity of Twente The Netherlands Email a y mersha s stramigioli r carloni utwente nl collision avoidance system for UAVs The feedback force is calculated based on an artificial force field Schill Mahony et al 12 13 propose the use of an admittance control framework for haptic teleoperation of UAVs furthermore the concept of optical impedance to provide a haptic feedback for obstacle avoidance is introduced Besides simulation results also an additional experiment of controlling the altitude of a real quadrotor is presented Stramigioli et al 14 present an approach which is based on an energy consideration and makes use of the concepts of network theory and port Hamiltonian systems to provide the human operator with a sensitive cognition of the environment Lee et al 15 introduce a haptic teleoperation framework to control mul tiple UAVs over the internet semi experimental results are presented for validation purposes To control the UAV s position the aerial vehicle is usually equipped with an on board position or velocity controller Accordi
6. ROS Tutorials 2 August 26 2011 Documentation Abeje Y Mersha and Riiesch Andreas Software Tool Package Version Robot Operation System ROS Diamondback 1 4 7 MATLAB Simulink 7 11 0 R2010b Eclipse IDE for C C Developers Helios Service Release 2 MS Visual Studio 2008 9 0 21022 8 RTM Table 1 Versions of used Software Tools Packages August 26 2011 3 Abeje Y Mersha and Riiesch Andreas Documentation 2 Overview This section provides an overview of all used hard and software components illustrated in Fig 1 Ad ditionaly a brief description of their functionalities and some important specifications are given fcu control serial link UART Oito HL 0 fcu debug fcu debug a teleop force feedba fcu imu_custom air_odometry UDP teleyp force_feedba Ay Windows ff Pose estimation groundstation exe A Vs OOF 70m x 3D View of Capture Area ROS core master ROS node ROS topic wired connection serial USB UDP connection Figure 1 System overview of the aerial test set up at UT 2 1 Hardware Components 2 1 1 Computers Ground station Laptop Specifications Linux Ubuntu 10 04 32bit Intel Quad Core Processor Main task runs the master side of the teleoperation furthermore the flight data is logged Tracker Ground station Desktop PC Specifications WinXp 32bit Intel Dual Core
7. control loop in either mode given the cascaded control loops are time scale separated and the control parameters of the haptic teleoperation loop fulfill the condition specified in Eq 8 IV SIMULATION RESULTS To validate the proposed algorithm simulation results are presented in this section The simulations were run with the software package MATLAB 21 to record the user s inputs and to display a force feedback to the operator a ForceDimension Omega6 haptic device 22 was used Note that the intention of this section is mainly to val idate the proposed mapping thus the slave device was simply modeled as a point mass furthermore a standard PID controller was used as a slave controller Comprehensive experiments with a real UAV are presented in Sec V In Fig 4 the results of a simple 1D simulation experiment are illustrated The top plot shows the position reference and simulated position of the UAV The second plot shows the position of the haptic device in the corresponding direction furthermore the force feedback and in the lowerst plot the switching between the direct A 1 and the sliding mode A 0 are illustrated The scaling factor Kp was set to one As can be seen in the plots although the workspace of the haptic device is limited to 0 2m the human operator is still able to cover a large aera with the proposed mapping method Note that the sliding can be aborted bringing the UAV to a complete stop or be e
8. eee EA ESS 14 AT VA GroundStation 0xe serra dol t dame 4 eee odd S o e ee 15 5 Tutorials 16 Ok Procede As SESS eo So ees a eee ee eee ee ee ee eee 16 5 1 1 Starting up the Tracking System sd dado edo doe ke Oe ees oh a Oe eG 16 HLZ Starting Up the Pelican 4 2 4 4 o 460 A CREAM Boo eR Se 16 5 1 3 Starting up the Haptic Teleoperation 0 0 000000 ee ee 18 5 2 Hanis tor ru bles LME ne Leda saa eas gy de ee a ete eee da BR E 18 A Appendix 19 Awl Code APIS 4 4h Po Gah bt AAA A ea ee eS eee 19 A 2 Overview of SVN Structure aooaa aa 19 A 3 Network Settings of WLAN of Flying Area 2 2 2 ee 20 Ts sas OCS A OR A A 20 August 26 2011 1 Abeje Y Mersha and Riiesch Andreas Documentation 1 Brief Introduction This manual briefly describe the starting up procedures for haptic teleoperation of aerial vehicles using haptic intefaces Omega6 and Phantom Omni and AscTec Pelican miniature flying vehicle that have been in use in the Robotic and Mechatronic RAM Lab of the University of Twente The procedures that are described here are far from being complete and comprehensive Moreover they are specific for our platform flying environment and hardware and software architectures we used for our experiments Besides of the operating instructions the hardware and software components are described within this manual 1 1 Safety Instructions Keep in mind that the rotors of the quadrotor spin with a quite high speed and due
9. upper PCB of the FCU Figure 2 Serial cable for connection between Figure 3 Bootload cable used for firmware up the Atom board and the FCU usually Atom date more information would be published by UART port 0 lt gt FCU HL serial 0 Asctec if such an update would be required Figure 4 Bootload cable probably as well just Figure 5 AscTec USB module used for inter needed for system updates action with the Asctec AutoPilot software and firmware updates of the HL processor usually FCU HL LL serial 0 lt gt USB 7 AutoPilot Software is downloadable form the customer download area of AscTec http www asctec de 83g53jT it is recommended to install the AutoPilot software including the corresponding drivers for the AscTec USB module illustrated in Fig 5 on a windows computer Instructions how to run it under Linux can be found in the CCNY wiki http robotics ccny cuny edu wiki AscTec August 26 2011 9 Abeje Y Mersha and Riiesch Andreas Documentation 3 2 1 Futaba Remote Control The remote control RC Futaba 7C 2 4GHz was as well purchased from AscTec It is used in the default configuration i e left stick up down for collective thruth input left stick left right for yaw input right stick up down for pitching and to the left right for rolling Furthermore two of the switches are used namely the red marked switch on the left side the so called GPS Switch and the black marked switch on the right si
10. 5 0 54 5 E g OF s 90 100 110 120 130 140 time sec Fig 8 Experimental results of the haptic teleoperation with the sliding mapping Top three plots commanded and actual position in x y and z direction 4 plot force feedback in z direction bottom switching awareness the human operator was additionally provided with a video stream from an off board camera Fig 9 shows an excerpt of the results of the experiment where the operator controlled all three translational DOF and the heading was kept constant As can be seen also in these experiments the trajectories produced by the sliding of the virtual point mass are smooth and are tracked by the slave controller with a high accuracy VI CONCLUSIONS The mapping algorithm proposed in the scope of this work disposes of high precision for small and fine opera tions furthermore 1t allows the human operator to overcome the workspace limitation of the haptic device and cover large distances in the unbounded workspace of the slave device in ET TT TT TTT y T 05 a E cn ae an ae E al T T l l l 7 nant EE pee L J l1 lI l e oly Ur E g l l l l E Op ry We AN I Ipod oly ly l l ly EZ poly oly j li l ly 8 0 551 il dell cn ie I
11. 6 2011 Documentation Abeje Y Mersha and Riiesch Andreas Visualeyez Instructional Videos installation To set up the tracker system the following procedure is recommended see also chapter III of the user manual p42ff 12 1 check if all required parts are available see above 2 insert and install the driver of the provided PCI bus card do not connect the tracker system to standard serial port 3 run the license installation with the PTI Key Installation CD AFTER the installation finished plug in the dongle 4 install VZSoft and whatever additional software you need from the Visualeyez Software CD do not install VZlicense 5 copy VZdriver dll and VZdriverN dll from the PTI Key installation CD to C WINDOWS system32 according to the README txt on the CD 6 set up the tracker system according to the instructional video Unpack and Set Up 7 start the VZSoft the instructional video VZSoft And Capture provides further useful informa tion about the tracking and capturing change log troubleshoot hints e the default coordinate system is not very handy can though be easily changed by following the procedure 1 recording a short take of 3 markers one placed in the desired origin second marker on the x axis and the thrid one some where in the xy plane 2 opening the System Settings gt User Options gt Coord Reference Frame 3 define coordinate reference frame with the With Current Take button and selec
12. 6 ACM 2011 P Pounds and A Dollar Uav rotorcraft in compliant contact Stability analysis and simulation in International Conference on Intelligent Robots and Systems 2011 F Bullo and R Murray Proportional derivative pd control on the euclidean group in European Control Conference 1995 Vinci Surgical System 21 22 23 24 25 26 27 28 29 30 31 MathWorks MATLAB Simulink http www mathworks com Force Dimension Omega 6 http www forcedimension com Ascending Technologies GmbH AscTec http www asctec de PTI PhoeniX VisualEyez VZ4000 http www ptiphoenix com J Challis A procedure for determining rigid body transformation parameters Journal of Biomechanics vol 28 no 6 pp 733 737 1995 ROS Robot Operating System http www ros org M Achtelik M Achtelik S Weiss and L Kneip ROS package asctec_hl_interface http www ros org wiki asctec_hl_interface 2011 C Roos C Hiierzeler and S Bouabdallah Design of a Collision Tolerant Airframe for Quadrotors ASL ETH Zurich 2009 Internal Report A Riiesch C Hitierzeler and J Nikolic Dynamicas Identification amp Validation and Position Control for a Quadrotor ASL ETH Zurich 2010 Internal Report M Burri J Nikolic and C Htierzeler Robust Flight Controller for Aerial Indoor Inspections ASL ETH Zurich 2011 Internal Repor
13. AEA L L i Li fi i l l Hdi l 100 110 120 130 140 150 160 170 time sec E T T I T TT TS e a 5 l I I E I l I l pos ref 3 I I pos UAV a im L Lai L ERRE E E T 140 150 160 170 m al s postition z dir m 2 a N force feedback N o Ne 100 110 120 130 140 150 160 170 time sec a T T T T T T T T 4 i E button 5 0 57 ss 5 o o D 100 110 120 130 140 150 160 170 time sec Fig 9 Inter country experiment reference and current position of the slave device in all directions furthermore the force feedback and switching between the two modes is illustrated a fast and intuitive manner The haptic teleoperation con troller with a kinetic scrolling based position mapping was successfully implemented and experimentally tested with two different set ups A rigorous stability analysis which takes the varying time delays and the switching between the two modes into account is conceivable as a topic of future work Furthermore an adaptive deceleration of the sliding through the operator would be imaginab
14. Admittance mode framework for haptic teleoperation of hovering vehicles with unlimited workspace in Australasian Conference on Robotics Automation 2010 R Mahony F Schill P Corke and Y Oh A new framework for force feedback teleoperation of robotic vehicles based on optical flow in Robotics and Automation IEEE International Conference on pp 1079 1085 IEEE 2009 S Stramigioli R Mahony and P Corke A novel approach to haptic tele operation of aerial robot vehicles in Robotics and Automation IEEE International Conference on pp 5302 5308 IEEE 2010 D Lee A Franchi P Giordano H Son and H Bulthoff Haptic Teleoperation of Multiple Unmanned Aerial Vehicles over the Inter net in IEEE Int Conf on Robotics and Automation 2011 H Rifai M Duc Hua T Hamel and P Morin Haptic based bilateral teleoperation of underactuated Unmanned Aerial Vehicles in FAC World Congress 2011 A Reetz C Gutwin T Stach M Nacenta and S Subramanian Superflick a natural and efficient technique for long distance object placement on digital tables in Proceedings of Graphics interface 2006 pp 163 170 Canadian Information Processing Society 2006 M Baglioni S Malacria E Lecolinet and Y Guiard Flick and brake finger control over inertial sustained scroll motion in Pro ceedings of the 2011 annual conference extended abstracts on Human factors in computing systems pp 2281 228
15. Description To realize the sliding of the reference position a virtual point mass m is introduced whose position x is in both modes proportionally mapped to the reference position of the aerial vehicle x For the direct mode the master device is coupled to the virtual mass by a stiff spring whereas in the sliding mode the virtual mass is uncoupled Furthermore a virtual viscous damping of the virtual mass is introduced as an external force which decelerates the mass during the sliding mode The operator is provided with a full control over the switching between the two modes e g through a button on the haptic device In Fig 2 the physical model of the core idea is illustrated for the one dimensional case The viscous damping is modeled to be proportional to the velocity of the virtual mass According to the principle of linear momentum the following equation of motion holds for the virtual point mass Myy k A y Lm dtv 1 where m o R represent the positions of the master device and the virtual mass respectively m denotes its mass d acts as a viscous damping coefficient and k A stands for the spring constant of the coupling depending on the state of the switch A Note that for the spring constant k A the following holds KO g if A 0 2 During the sliding phase the virtual viscous damping ensures that the virtual mass eventually comes to a stop It can be easily verified from Eq 1
16. Processor Main task runs the tracker interface VZsoft to record marker data additionally the pose of the UAV is estimated and transmitted to the vehicle s position controller Atom carrierboard On board Specifications Linux Ubuntu 10 10 32bit Intel Atom 1 6 GHz processor brief manual provided by AscTec 3 Main task runs the interface to the flight control unit FCU thus the slave side of the teleoper ation 4 August 26 2011 Documentation Abeje Y Mersha and Riiesch Andreas 2 1 2 Peripherials Haptic Device The Force Dimension Omega6 7 was used for the experiments The Omega6 provides translation as well as rotation sensing with high accuracy furthermore it is featured with a precise gravity compensation to enable accurate hapitc transparency Translational forces can be displayed con tinuously up to 12N The set up is though compatible for other haptic devices only tested in semi experiments for the Phantom Omni Aerial Vehicle As an aerial platform the AscTec Pelican quadrotor 2 was used for the experiments This quadrotor disposes of a high payload capacity up to 500g and agility The helicopter is provided with all essential on board sensors plus two ARM7 micro processors which build the the so called Flight Control Unit FCU also called Autopilot in the manual of AscTec 4 External Positioning System As an external positioning system a PTI PhoeniX VisualEyez VZ 4000 tracker unit is used 11 The
17. UAV off If you are interested in flying the Pelican from the RC follow the steps suggested in the AscTec manual 4 Proceed to the next step if you want to do autonomous flight or teleoperation To log data for offline analysis change into a desired directory and run the air_logger e g use the following command mkdir FlightTest FlighTest testMMDD FlightTest testMMDD testXX cd FlightTest testMMDD testXX rosrun air_logger air_logger For way point tracking activate the way point server client by typing for further information of its usage see 1 rosrun asctec_hl_interface waypoint_server skip and proceed to the next step if you don t need to do way point tracking For trajectory tracking define your trajectory in the air_hapticteleop package with in the emulatedHaptic cpp file and compile and build the package Type the following command to run this reference trajectory rosrun air_haptic_teleop air_talker skip and proceed to the next step if you don t need the predefined trajectory tracking August 26 2011 17 Abeje Y Mersha and Riiesch Andreas Documentation 5 1 3 Starting up the Haptic Teleoperation 1 Start up the haptic interface Currently Phantom omni Omega6 If you use phantom omni type the following on the terminal rosrun phantom_omni omni If you use Omega6 make sure you switch it on for use calibrate it according to 8 it is highly recommended that you read the manuals of the respective h
18. University of Twente EEMCS Electrical Engineering Control Engineering Kinetic Scrolling based Position Mapping for Haptic Teleoperation of Unmanned Aerial Vehicles Andreas Ruesch MSc report Supervisors Prof dr ir S Stramigioli Dr R Carloni MSc A Y Mersha August 2011 Report nr 014CE2011 Control Engineering EE Math CS University of Twente P O Box 217 7500 AE Enschede The Netherlands m Kinetic Scrolling based Position Mapping for Haptic Teleoperation of Unmamned Aerial Vehicles A Rtiesch A Y Mersha S Stramigioli and R Carloni Abstract In this paper we present a haptic teleoperation control algorithm for unmanned aerial vehicles applying a kinetic scrolling based position mapping The proposed algo rithm disposes of high precision for small and fine operations Additionally it allows to overcome large distances in the unbounded workspace of the aerial vehicle in a fast and intuitive manner For validation purposes results of simulations and experiments are presented I INTRODUCTION The remote control of unmanned aerial vehicles UAV represents a challenging task which in general requires a lot of experience and an excellent instinct by the pilot Thus in the recent past a lot of research has been conducted and progress in developing autonomous UAVs has been made by different parties for various applications and different vehicle configurations e g 1 5 Nevertheless there s
19. ability The simulation results are shown in Sec IV In Sec V the results of the flight experiments with a real UAV are presented Conclusions and future work are discussed in Sec VI Il PRELIMINARIES This section briefly presents some background knowledge of haptic teleoperation applied on UAV followed by a brief introduction of the kinetic scrolling A Haptic Teleoperation for Unmanned Aerial Vehicles The scheme of a typical haptic teleoperation control loop is illustrated in Fig 1 As can be seen the interaction of the human operator with the aerial vehicle slave device through the haptic device master device is bilateral The master and the slave side are equipped with a separate controller the master controller s main tasks are to map the user s inputs to the corresponding reference of the slave device and to compute and display the force feedback on the master device On the other side the slave controller ensures that the slave is following the desired trajectory or velocity depending on the configuration The communication channel between the master and slave device is typically unreliable and usually introduces unknown and probably even time varying delays into the control loop Slave Side Master Side Aerial Vehicle G 2 de e Y Environment Ui I Xs a T at Slave Ze Controller Human Operator cation Channel Fig 1 Scheme of a haptic teleoperation control loop W
20. ain e most probably VZsoft is not running or no markers are active within VZsoft 4 the omega6 package can not connect to the haptic device e check if connected by a USB 2 0 port NO USB 3 0 e check write permissions see section 3 1 5 general tip CHECK THE PLUG 18 August 26 2011 Documentation Abeje Y Mersha and Riiesch Andreas A Appendix A 1 Code APIs All Code APIs are provided within the corresponding ros package namely in the doc subfolder A list of the corresponding links is provided in the following air_hapticteleop link svn airobots_ut TeleopAlgorithms Uav Implementation Ros air_hapticteleop doc air_hapticteleop html1 index html omega6 link svn airobots_ut Devices Haptic Omega6 Ros omega6 doc omega6 html index html groundstation exe link svn airobots_ut Devices Tracker GroundStation doc html index html A 2 Overview of SVN Structure The source code and documentation of the described set up above is found in the internal SVN of the AlRobot Group at the University of Twente An overview of the structure of the file system of the used compentents is given in the following Note all ros packages are implemented according to the ROS standard 14 svn airobots_ut Devices svn airobots_ut Devices Camera svn airobots_ut Devices Haptic svn airobots_ut Devices Haptic Omega6 svn airobots_ut Devices Haptic Omega6 Drivers svn airobots_ut Devices Haptic Omega6 Ros svn airobots_ut Devices Haptic Omega6 Ro
21. aptic interfaces if you are using it for the first time Type the following rosrun omega6 omega6 2 Last but not least start up the haptic teleoperation package depending on the mode see 4 1 you have also to start the executable of the Real Time Workshop of MATLAB Simulink Thus for the package type rosrun air_haptic_teleop air_haptic_teleop and if required for the Simulink target executable typically something like workspace lt NameOfSimulinkFile gt CustomMW lt NameOfSimulinkFile gt and then connect within the Simulink model to its target executable CTRL T 5 2 Hints for Troubleshooting The points listed in the following might help if you run in any problems with the set up but keep in mind that the system is in an early pre release stage The Authors but their best effort in making this set up working properly and safely any bug fix or addition is welcome though 1 no ssh connection to the Atom possible port 22 Connection timed out e connect the external keyboard to the Atom to any of the mini USB ports press ENTER in the case Ubuntu didn t properly boot happens sometimes if Atom crashes cause of power failure e check the connection IP addresses of ground station ping Atom 2 the asctec_hl_interface can t connect to the FCU timeout e kill the launch file e turn the FCU on and off leave the Atom running e try again 3 pose estimation software does not start just pops up and desappears ag
22. ch Andreas Documentation e Documentation section 4 4 asctec_hl_ interface e Main task provides an interface for ROS to the FCU e Documentation puplished on the ROS wiki 1 e Developed by Markus Achtelik Michael Achtelik Stephan Weiss Laurent Kneip e Version downloaded and installed on the 28 06 11 Change log 28 06 11 arue changed default values in launch fcu_parameters yaml of state_estimation to HighLevel_SSDK and of position_control to HighLevel 28 06 11 arue added launch of the NudpServer ROS node to the fcu lauch file 2 2 2 Additional Executables VZSoft e Main task provides an interface to the tracker to record the markers position e Documentation VZ manual 12 VZ GroundStation exe e Main task estimates the UAV s pose from the markers measurments and sends the estimation through UDP to the UAV e Documentation section 4 7 2 3 General Remarks e Note all coordinate systems are if not explecitly denoted differently according to the East North Up enu convention according to the ROS coordinate frame convention http www ros org wiki geometry CoordinateFrameConventions 6 August 26 2011 Documentation Abeje Y Mersha and Riiesch Andreas 3 Hardware In this section all used devices are introduced The links to manuals documentation and hints to install the devices might or also not be useful are provided 3 1 Force Dimension Omega6 Following descriptio
23. de the so called Serial Interface Switch Note all inputs are with respect to a body fixed North East Down NED frame direction of the x axis is marked by an orange tag on the Pelican Fig 6 illustrates the RC with all switches and sticks in their default positions For reconfiguration of the RC the reader is referred to the AscTec manual 4 Figure 6 RC with all switches and sticks in their default positions 1 e all switches point away from the operator and the two sticks are in the zero position for roll pitch yaw and collective thrust 3 3 PTI Visualeyez VZ 4000 Tracker System Following description holds for the interaction of the device with a WinXP machine brief intro Motion capturing device for external position sensing of the UAV to provide the position controller with the necessary information about the current position of the UAV link doc Visualeyez User Manual ver 3 6 0 12 stored on the Visualeyez Software CD hard copy available at CE requirements the tracker system is stored in the following four boxes for a detailed system contents list see page 14 of the user manual e ashipping carrying case containing the motion tracking unit e two cardboard boxes containing the required cables adapters markers e one small cardboard box containing the software and dongle license the following 3 CDs are required for the installation Visualeyez Software CD PTI Key Installation 10 August 2
24. e this is only required to access the internet with the Pelican e g for software updates during the flight test a standalone network is used which can be accessed without any special tricks e add file eap tt1s to etc wicd encryption templates e sudo chmod 755 etc wicd encryption templates eap ttls e echo eap ttls sudo tee a etc wicd encryption templates active e in the wicd gui set the following properties Identity sXXX XXX X Qutwente nl Path to CA Cert etc ss1 certs GTE_CyberTrust_Global_Root pem Anonymous Identity sXXXXX XX utwente nl Protocol WPA Encryption TKIP Password your password 20 04 11 arue installed ros diamondback base installation 28 06 11 arue installed the ros package asctec_mav_framework 1 including the required HL firmware update troubleshoot hints e always turn the FCU on if the Atom board is running Otherwise there is no warning beep sound if battery voltage drops too low can result in a permanent damage of the batteries e it is possible to use an external power supply for the Pelican The external power supply is though not powerful enough for actual flight maneuvers but recommended if long on ground task of the Atom are required e g system updates e if the monitor is connected to the Atom board the graphical interface of Ubuntu can be started with startx e if a rotor controller has to be exchanged a reconfiguration of them i
25. e analysis by Bullo and Murray for stabilizing a rigid body with PD control 20 As depict in Fig 3 an additional cascaded loop for the master controller of the haptic teleoperation is employed again under the assumption that the cascaded loops are time scale separated Hence the stability of the master controller can be analysed independently For this purpose the haptic device is modeled as a mass spring damper system whereas the intrinsic damping is assumed to be marginal Primarily the direct mode is considered therefore the switch of the mapping is closed A 1 As illustrated in the flow diagram Fig 3 the inputs to the master controller consist of the force applied by the operator Fy and the position of the slave device Is ie u FH 2s o the desired reference of the slave x represents its output i e y x The states of the subsystem are the positions and velocities of the master device and of the virtual mass respectively 1 e for the state vector holds x m 2m dv xv Thus the dynamics of the subsystem are described by the following system matrices a j o k4 a Kee Mh Mh Mh Mh ale 1 0 0 0 0 0 0 ke d Ke 0 0 c d 0 0 0 0 0 0 6 with k Kpu Kpr and Ka dy where dp represents the internal damping of the haptic device and mp its mass It can be easily verified that for the characteristic poly nomial of the linear system given in Eq 6 holds det sI A st
26. e the package is within your ROS_PACKAGE_PATH 2 run the following command August 26 2011 13 Abeje Y Mersha and Riiesch Andreas Documentation roscd udpServer cmake CMakeList txt rosmake configurations e the UDP port is specified through the macro UDP_PORT e besides the main executable pubTf two additional ones are provided for debuging purposes namely talker puplishes a virtual fake pose of the UAV without listening to the UDP port it is strongly recomended to not use this executable during real flight tests stateEstimation puplishes besides the pose of the UAV a simple estimation of the UAV s translational velocity for bypassing the on board estimator Not yet tested 4 5 ROS Message hapticteleop msgs brief summary ros message type to store the state information of the haptic device Furthermore also a message type for the desired reference position including a heading angle is provided requirements depending on the std_msgs and geometry_msgs installation the following procedure is recommended 1 make sure the package is within your ROS_PACKAGE_PATH 2 run the following command roscd hapticteleop_msgs cmake CMakeList txt rosmake configurations 4 6 MATLAB Simulink target model brief summary runs the actual haptic teleoperation if the air_hapticteleop package is in the corre sponding mode requirements MATLAB Simulink including Realtime Workshop RTW installed Furthermore Ecl
27. ec_hl_comm Furthermore if run in the MATLAB Simulink mode the corresponding software package has to be installed installation the following procedure is recommended 1 make sure the package is within your ROS_PACKAGE_PATH 2 run the following command roscd air_hapticteleop cmake CMakeList txt rosmake configurations e currently three different modes are provided all are derived from the base class HapticTeleop cpp To run the package in a desired mode create an instance of the corresponding derived class in the main cpp file Direct Mapping this mode allows a proportional mapping of the user s input to the slave s reference where the force feedback is proportional to the deviation of the slave s com manded and current position The haptic teleoperation is only active as long as the user presses the button on the end effector of the haptic device Sliding Mapping this mode contains an implementation of the kinetic scrolling based map ping within c The user can switch between its two modes by pressing and releasing the button on the end effector of the haptic device Simulink Mode this mode is mainly used for the experiments it builds a local UDP bridge to a MATLAB Simulink RTW target where the actual haptic teleoperation algorithm is running Thus it allows a high usability and fast prototyping of algorithms Note a reference position is only send to the UAV if the Force button of the haptic device
28. estimation of the UAV is according to fixed World frame whose origin is shifted to the initial zero position of the c g thus if the UAV is on the ground its z component is zero 8 Armadillo C linear algebra library http arma sourceforge net August 26 2011 15 Abeje Y Mersha and Riiesch Andreas Documentation 5 Tutorials In the first part of this section a tutorial over the required procedures to autonomously fly or haptic telemanipulate the Pelican is given The second part provides some hints for troubleshooting 5 1 Procedures It is assumed that all components described in section 2 4 are installed and work properly otherwise the reader is kindly referred to the corresponding sections of this manual The general procedure for the haptic teleoperated flight tests consists of the following steps 1 starting up the tracking system 2 starting up the Pelican 3 starting up the Haptic Teleoperation 4 enjoy the noise and force feedback Note since the life span of the batteries is quite limited it is recommended to prepare as much as possible before powering the Pelican up i e terminals on the ground station can already be opened and the corresponding command be written Note2 keep in mind that the Pelican should only be flown in the presents of a safety pilot who is able to take over the control of the UAV in the case of any failure or emergency 5 1 1 Starting up the Tracking System 1 Start up
29. esults of the experimental tests are presented In the first part the set up described above Sec V A was used to perform the experiments Additionally some results of an inter country experiment where the operator and aerial vehicle were locally separated are shown The top plot of Fig 7 shows the altitude of the UAV during the experiment where the operator s input is similar to the one used during the simulation presented in Sec IV The operator first commands the UAV in the direct mode before he slides the vehicle up at the end of the plot again the extension of the sliding can be seen The displayed force feedback and the switching between the two different modes are shown in the two lower plots of Fig 7 pos ref pos UAV ostition z dir m amp N o N T A T force feedback z dir N state of switch o al o T button i l l l 85 90 95 100 105 110 time sec Fig 7 Experimental results of the haptic teleoperation with the kinetic scrolling based position mapping Top commanded and actual altitude middle force feedback in z direction bottom switching between the two operation modes A larger excerpt of the experimental results in all direc tions x y and z is illustrated in Fig 8 A
30. here m represents the position of the haptic device x the reference position of the UAV s its actual position Furthermore the applied force by the human operator is denoted with F y7 the feedback force with Fp the interaction forces of the UAV with the environment are represented with F s and Fg and the input commands of the slave controller are denoted with u B Kinetic Scrolling Computer technology and graphics have dealt with workspace and display limitation for ages therefore various forms of scrolling are common and well established methods to overcome this limitation On devices with a touchscreen e g on smart phones the so called kinetic scrolling method became standard in the recent past The user is provided with two different input modes as long as his finger is in contact with the touchscreen its movements are directly mapped to the displacement of the screen contents The displacement of the screen contents 1 e the scrolling does not necessarily stop immediately when the user releases his finger from the input device it is able to move further and decelerates automatically till it eventually comes to a complete stop The amount of this additional scrolling is defined by the speed of the user s motion just before he releases the contact Thus for large distances a fast scrolling can be applied without losing the high accuracy and usability for small precise manipulations Kinetic scrolling is in literature al
31. ic teleoperation with the kinetic scrolling based position mapping for different damping coefficients SIM1 d d SIM2 da 2d SIM3 d3 d 2 virtical dashed lines indicate the switching V EXPERIMENTS This section first describes the experimental set up used during the flight experiments with a real aerial vehicle followed up by presenting the experimental results A Experimental Set up The flight experiments were conducted in an indoor test area size about 4 00m x 3 75m x 2 75m which meets the necessary safety precautions A complete system overview is depicted in Fig 6 1 Aerial Vehicle As an aerial platform the AscTec Pel ican quadrotor 23 was used for the experiments This quadrotor disposes of a high payload capacity up to 500g and agility The helicopter is provided with all essential on board sensors plus two ARM micro processors which build the so called Flight Control Unit FCU Furthermore it 1s equipped with an additional processor board based on an Intel Atom 1 6 GHz processor which entails high computational on board power 2 Haptic Device The human operator interacts with the aerial vehicle through the Force Dimension Omega 6 haptic device 22 This device provides translation as well as rotation sensing with high accuracy and it is featured with a precise gravity compensation to enable accurate hapitc transparency Translational forces can be displayed continuously up to 12N The provided F
32. ional Conference on pp 1642 1648 IEEE 2010 N Michael D Mellinger Q Lindsey and V Kumar The grasp multiple micro uav testbed Robotics amp Automation Magazine IEEE vol 17 no 3 pp 56 63 2010 M Achtelik M Achtelik S Weiss and R Siegwart Onboard imu and monocular vision based control for mavs in unknown in and outdoor environments in Proc of the IEEE International Conference on Robotics and Automation 2011 Innovative Aerial Service Robots for Remote Inspection by Contact AIRobots http www airobots eu Intuitive Surgical The da http www intuitivesurgical com W Chou and J Xiao Haptic teleoperation of robotic manipulator Robotic welding intelligence and automation pp 51 59 2007 T Lam M Mulder and M Van Paassen Haptic Feedback for UAV Tele operation Force offset and spring load modification in Systems Man and Cybernetics IEEE International Conference on vol 2 pp 1618 1623 IEEE 2006 T Lam M Mulder and M Van Paassen Haptic feedback in uninhabited aerial vehicle teleoperation with time delay Journal of Guidance Control and Dynamics vol 31 no 6 pp 1728 1739 2008 T Lam H Boschloo M Mulder and M Van Paassen Artificial force field for haptic feedback in UAV teleoperation Systems Man and Cybernetics Part A Systems and Humans IEEE Transactions on vol 39 no 6 pp 1316 1330 2009 F Schill X Hou and R Mahony
33. ipse Helios was used as an IDE tool installation to compile and build the Simulink model press CTRL B configurations e to set up MATLAB to use Eclipse as its IDE tool run the following command within the MATLAB command window is only the frist time required eclipseidesetup e make sure you have the Target Preferences block set up proberly within your target model Furthermore a UDP receive and send block are required to interact with the air_hapticteleop ros package 14 August 26 2011 Documentation Abeje Y Mersha and Riiesch Andreas 4 7 VZ GroundStation exe brief summary since VZsoft does only provide position measurements for the LED markers the pose of the UAV has to be estimated This is done by applying the algorithm proposed by Challis et al 6 The executable makes use of the VZ SDK and publishes the estimation through a UDP bridge to any subscriber requirements VZsoft has to be started and the corresponding markers have to be active before the GroundStation exe can be started Futhermore make sure all configuration files are available in the working directory and the Armadillo C library is installed installation no installation required configurations e the following files are used to configure the software udpSettings ini ini file for default UDP Settings host IP and UDP port see below for temporary change MarkerZeroConfig txt contains the initial zero configuration of the LED markers with re
34. is activated e to emulate the haptic device i e letting the UAV autonomously follow a predefined traje cetory an additional executable is provided air_talker the trajectory is defined in the emulatedHapticDev cpp file e for the inter country experiment with ETH Zurich different naming of couple topics is re quired to do so enable the corresponding precompiler macro __EXP_ETH__ in the main header Note a model of their platform slave incl slave controllers is provided in the ros package air_model which can be used for preliminary tests simulations and debug purposes More detailed information to their set up can be found in 13 15 5 12 August 26 2011 Documentation Abeje Y Mersha and Riiesch Andreas 4 2 ROS Package air logger brief summary logs the flight data for offline analysis namely the following ROS topics teleop haptic_state teleop force_feedback fcu control fcu debug fcu imu_custon air_odometry The topics are stored in separated text file in the current directory thus it is rec ommended to change into the desired directory before starting this node Furthermore note that new data is added at the end of the files thus it is recommended to use different directories for different experiments requirements the ros package requires the following packages to be installed std_msgs geometry_msgs nav_msgs hapticteleop_msgs and asctec_h1_comm installation the following procedure is rec
35. le e g through a pressure sensitive device The integration of vision sensors for better environmental awareness of the human operator is consider able as well as tests without the high precision of an external positioning system instead vision based flight control could be used which would influence the performance of the position controller and thus also of the teleoperation VIl ACKNOWLEDGMENT Sincere thanks are expressed to Micheal Burri Janosch Nikolic and Christoph Hiirzeler of the Autonomous Systems Lab of ETH Z rich for their support and the realisation of the inter country experiment 1 2 3 4 5 6 a 7 8 9 10 11 12 13 14 15 16 17 18 19 20 REFERENCES G Hoffmann D Rajnarayan S Waslander D Dostal J Jang and C Tomlin The stanford testbed of autonomous rotorcraft for multi agent control starmac in Digital Avionics Systems Conference The 23rd vol 2 pp 12 E IEEE 2004 S Bouabdallah and R Siegwart Backstepping and sliding mode techniques applied to an indoor micro quadrotor in Robotics and Automation 2005 ICRA 2005 Proceedings of the 2005 IEEE Inter national Conference on pp 2247 2252 IEEE 2005 S Lupashin A Schollig M Sherback and R D Andrea A simple learning strategy for high speed quadrocopter multi flips in Robotics and Automation IEEE Internat
36. mAA9C6C Band 2 4 GHz 802 11n Pre sharedKey N6M2YQCXDVIY Router MAC addr 00 0C F6 AA 53 ED IP addr 192 168 0 1 Groundstation Laptop Ubuntu 10 04 Host name ruesca MAC addr LAN 88 AE 1D B1 83 54 IP addr 192 168 0 100 Groundstation WinXP Host name CE169 MAC addr LAN 00 13 20 81 BF FF IP addr 192 168 0 105 Pelican Ubuntu 10 10 Host name asctec atom MAC addr WLAN 00 0E 8E 30 90 0D IP addr 192 168 0 112 A 4 Passwords FOR INTERNAL USE ONLY the used passwords are provided in the following Router SitecomAA9C6C user admin pw admin Groundstation WinXP 20 August 26 2011 Documentation user admin pw airobots Pelican Ubuntu 10 10 user atom pw pelican August 26 2011 Abeje Y Mersha and Riiesch Andreas 21 Abeje Y Mersha and Riiesch Andreas Documentation References 1 14 15 16 22 M Achtelik M Achtelik S Weiss and L Kneip ROS package asctec_hl_ interface http www ros org wiki asctec_hl interface 2011 Ascending Technologies GmbH AscTec http www asctec de AscTec CoreExpress Carrierboard Manual v1 0 http www asctec de manuals AscTec Hummingbird with AutoPilot User s Manual http www asctec de manuals M Burri J Nikolic and C Htierzeler Robust Flight Controller for Aerial Indoor Inspections ASL ETH Zurich 2011 Master Thesis J Challis A procedure for determining rigid body transformation parameters Journal of Biome
37. manual 4 of the Pelican before starting up the pelican for the first time 16 August 26 2011 Documentation Abeje Y Mersha and Riiesch Andreas 10 Startup a roscore from a ground station PC running ubuntu in which ROS is installed Type the following command in the terminal roscore Access the Atom board of the Pelican through the following command ssh asctec asctec atom Type the following command on the terminal roslaunch asctec_hl interface fcu launch The above command starts up the asctec_hl_interface and the udpServer Do the sanity checks recommended in the tutorial of the ros package ros_asctec_hl_interface before running its trajectory tracking controller 1 Note that the recommended check for the velocity an bias can only be done if the serial interface on the RC is switched on The position sanity check can be done without it Switch off the serial port of the RC if it is still switched on from the previous step Make sure all switches on the RC are off and the sticks are on their default position At this step you are ready to fly the asctec Pelican Start up the motors of the Pelican by moving the yaw stick fully either to the right or to the left and releasing it as soon as the propellers start to rotate All propellers of the pelican should be rotating at almost the same angular velocity as long as the pelican is not tilted The thrust generated by the propellers is not enough to lift the
38. n holds for the interaction of the device with a Linux Ubuntu 10 04 10 machine brief intro Haptic device used for the teleoperation experiments The Omega6 disposes of high accuracy in measuring the translational and rotational link doc the setup and installation is described in the provided user manual 8 documentation of the provided SDK can be found within its doc directory open the index html file with your favored web browser requirements before starting to install the Omega6 make sure 1 you have the current Haptic SDK dhd 3 3 1 1556 linux i686 tar gz file is provided on the Force Dimension USB drive or downloadable form the Force Dimension website 2 the GLUT libglut3 dev and USB programming library development files Libusb 1 0 0 dev have to be installed on your linux system sudo apt get install libglut3 dev libusb 1 0 0 dev installation described in chapter 5 of the user manual 8 change log troubleshoot hints e it is recommended to build the examples cd dhd 3 3 1 examples make and run one of them to check if everything works fine thus e g type to run the gravity example dhd 3 3 1 bin gravity e Note that you need to have write access on the corresponding usb port For only giving the user a temporary write access type the following command everytime you plug the device in sudo chmod 666 port_address For a permanent change i e if you don t want to type the command above everytime adj
39. n to his stimulations as well as to external disturbances e g to wind gusts The first term of the displayed force is proportional to the difference between the commanded and actual slave position which gives an indication of the magnitude and direction of the positional deviation Furthermore to avoid too harsh or too rapid movements of the haptic device an additional damping of its velocity is proposed Thus for the force feedback vector holds Fp Kyp s Kapatm 5 where Kp and Kg denote the corresponding scaling parameters C Stability Consideration During any telemanipulated flight maneuver the stability of the aerial vehicle is crucial for the success of the opera tion Hence in the following some important consideration concerning the overall stability of the proposed teleoperation algorithm are shown The flow diagram of the complete haptic teleoperation loop is illustrated in Fig 3 As can be seen the UAV is provided with a flight controller which is stabilizing the vehicle during its flight For this purpose typically a cascaded control strategy is chosen where the UAV s rotational dynamics are treated separately from its translational ones e g 2 5 19 An approach like this is usually feasible given the two sets of dynamics are time scale separated As Pound et al 19 show the free flight stability for an UAV can be ensured by two cascaded PD controllers and be proven by applying th
40. ngly the input consists of a corresponding reference and a desired heading angle In classical haptic teleoperation where the haptic device is typically a replica of the slave de vice and thus disposes similar kinematics a direct mapping of the master s position to the slave s is common Caused by the dissimilarities of the kinematics of an aerial vehicle and of a hapitc device an alike direct mapping is usually not feasible Moreover the workspace of a hapitc device is limited and quite small compared to the UAV s which is essentially infinite and unbounded In order to overcome these limitations the commonly used approach in literature e g 10 15 16 is to map the displacement of the haptic device to a reference velocity of the UAV This mapping method causes a trade off in the precision and the ease of use of the haptic teleoperation The contribution of this paper is a new approach to over come the limitations of the workspace of the haptic device The approach is inspired and based on kinetic scrolling For validation purposes simulation and experimental results are presented The paper is organized as follows In Sec II some preliminary information about haptic teleoperation applied to UAVs and about kinetic scrolling is given In Sec HI the proposed haptic teleoperation algorithm is introduced including the kinetic scrolling based position mapping the proposed force feedback and some consideration about its st
41. ommended 1 make sure the package is within your ROS_PACKAGE_PATH 2 run the following command roscd air_logger cmake CMakeList txt rosmake configurations 4 3 ROS Package omega6 brief summary provides an ROS interface for the interaction with the Force Dimension Omega 6 haptic device It publishes the current state of the haptic device and displays a desired force feedback to the operator This package makes use of the HapticSDK provided by Force Dimension See 8 for a detailed documentation of the HapticSDK requirements the Omega6 has to be installed on the machine see section 3 1 furthermore the package requires the following ros packages to be installed std_msgs geometry_msgs and hapticteleop_msgs installation the following procedure is recommended 1 make sure the package is within your ROS_PACKAGE_PATH 2 run the following command roscd omega6 cmake CMakeList txt rosmake configurations 4 4 ROS Package udpServer brief summary server of th UDP bridge between the tracker ground station and the aerial vehicle it puplishes the received estimation of the UAV s pose within ROS A warning is puplished if the node does not receive a message form the ground station within a certain time period requirements the package requires the following ros packages to be installed std_msgs geometry_msgs and nav_msgs tf roscpp and asctec_hl_comm installation the following procedure is recommended 1 make sur
42. orce Dimension SDK 22 is used as a software interface to the device 3 External Positioning System As an external position ing system a PTI PhoeniX VisualEyez VZ 4000 tracker unit is used 24 The tracker captures the motion of the active markers LED which are mounted on the Pelican The absolute position measurements of those markers are used for the estimation of the UAV s pose Since the VisualEyez VZSoft does not provide an estimation of the pose of a rigid body this estimation is run on the ground station according to the algorithm proposed by Challis in 25 4 Software Both the on board atom processor board and the ground station computer are equipped with a Ubuntu Linux 10 10 furthermore the so called Robot Operating System ROS 26 framework is used as a middleware The ground station executes the teleoperation algorithm and a ROS interface to the haptic device Furthermore the UAV s pose is estimated from the measured marker data On board a ROS interface is running on the Atom board additionaly the position and attitude controller of the UAV are executed on the FCU As a position controller a simple PID controller with a feedthrough term is used as proposed and provided by 5 27 the attitude controller is based on a PD algorithm and is provided by AscTec 23 The aerial vehicle communicates with the ground station over a WiFi data link 802 11n standard B Experimental Results In the following the r
43. s can be seen after the direct operation and sliding slowly in almost only one direction at the beginning the user is also able to slide the UAV rapidly in multiple direction simultaneously as shown at the end of the experiment Note that the heading of the UAV was kept constant during the whole flight The plots show that the mapping works fine even in the presents of an average performance of the position control and with varying communication delays The transition between the two modes is smooth and results in a sleek trajectory As stated above besides the local experiments an addi tional experiment was performed where the human operator and the aerial vehicle were geographically far separated and communicated through a standard internet connection The master side including the operator were located at the University of Twente Netherlands whereas the UAV and its controller were flying at the ETH Z rich Switzerland During this experiment a different quadrotor was used it is equipped likewise with a FCU provided by AscTec 23 the airframe and position controller are developed by the ASL 28 30 though Furthermore a Vicon System 31 was used as an external positioning system For a better environmental Ref FF Haptic Teleop w Kinetic Scrolling 0 e Ctrl Inputs UAV Data Data Exchange Flight Ctrl Unit r s 802 11n Le UAV Pose Pose Estimation
44. s omega6 svn airobots_ut Devices Haptic Phantom0Omni svn airobots_ut Devices Haptic PhantomOmni Drivers svn airobots_ut Devices Haptic PhantomOmni Ros svn airobots_ut Devices Haptic Phantom0mni Ros phantom_omni svn airobots_ut Devices Manipulator svn airobots_ut Devices Tracker svn airobots_ut Devices Tracker GroundStation svn airobots_ut Devices Tracker tools svn airobots_ut Devices Tracker udpServer svn airobots_ut Devices Uav svn airobots_ut Devices Uav Matlab svn airobots_ut Devices Uav Pelican svn airobots_ut Devices Uav Ros svn airobots_ut Devices Uav Ros air_model svn airobots_ut Papers svn airobots_ut TeleopAlgorithms svn airobots_ut TeleopAlgorithms Manipulator svn airobots_ut TeleopAlgorithms Uav svn airobots_ut TeleopAlgorithms Uav Implementation svn airobots_ut TeleopAlgorithms Uav Implementation Matlab svn airobots_ut TeleopAlgorithms Uav Implementation Matlab virtual_ref_mass svn airobots_ut TeleopAlgorithms Uav Implementation Ros svn airobots_ut TeleopAlgorithms Uav Implementation Ros air_hapticteleop August 26 2011 19 Abeje Y Mersha and Riiesch Andreas Documentation svn airobots_ut TeleopAlgorithms Uav Implementation Ros air_logger svn airobots_ut TeleopAlgorithms Uav Implementation Ros hapticteleop_msgs svn airobots_ut TeleopAlgorithms Uav Simulation A 3 Network Settings of WLAN of Flying Area The current settings of the network are provided in the following Network Settings Flying Area AlRobots CUT SSID Siteco
45. s required by following the procedure CCNY wiki http robotics ccny cuny edu wiki AscTec Ubuntu Scan be found in the svn see also Appendix A 2 8 August 26 2011 Documentation Abeje Y Mersha and Riiesch Andreas 1 Connect the AscTec AutoPilot PC Software 7 with the serial cable to the low level pro cessor of the FCU LL serial 0 2 select corresponding port in the AutoPilot software and press Connect 3 press down Shift select Tools gt Motor Setup release shift 4 start the Motor Assignment Assistent and follow its instructions e Follow the procedure described in 9 on p 18 Link Procedure to reconfigurate the RC trans mitter with its receiver This is necessary if you want to fly the Pelican with a different RC or e g if you had to send in the Pelican since AscTec usually tests the set up before sending it back and maybe without mentioning that the reprogrammed the receiver to accomplish this e AscTec provides three undocumented serial cables see Fig 2 4 for describtion Furthermore the AscTec USB module is illustrated in Fig 5 e Note that the Pelican should never be powered up with demounted rotor blades a motor controller was previously blown up while doing so According to AscTec the reason might be that otherwise the motor controllers choke e Furthermore starting problems of the FCU occurred through two bended pins of the HL serial O port the bending caused a short circuit on the
46. so known as flicking releated work can be found in 17 18 As stated above kinetic scrolling became standard on modern smart phones where it allows the user to interact with his gadget in a natural and intuitive manner This inspired and motivated the mapping of the operator s inputs to the reference signal of the slave device of the teleoperation control loop proposed and described in Sec III MI HAPTIC TELEOPERATION WITH A KINETIC SCROLLING BASED POSITION MAPPING A Kinetic Scrolling based Position Mapping This section describes a new approach to overcome the limitation of the workspace on the master side based on the kinetic scrolling described in Sec II B 1 Core Idea Like the kinetic scrolling the mapping algorithm is divided into two modes namely a direct and a sliding mode For the direct mode a proportional mapping of the master s position to the slave s reference position is proposed Whereas in the sliding mode the operator is provided with the possibility to slide the reference position away the sliding is decelerated automatically similar to the kinetic scrolling on smart phones The amount of the sliding is influenced by the user s speed in the direct mode before switching to the sliding mode Note that in both modes a reference position is transmitted to the on board position controller of the aerial vehicle thus there is no need to switch between different slave controllers 2 Mathematical
47. spect to the c g of the UAV This file can be automatically generated by using the MATLAB script getZeroConfig m found in the subfolder tools To use the script do the following 1 mount the markers on the UAV make sure they are fix 2 align the UAV s body frame with the fixed World frame avoid any rotation or shift in xy direction 3 start capturing a data set with the VZsoft Note at the beginning at least 4 markers should be visible 4 take the UAV of the ground and start tilting and moving slowly till you captured all markers at least once in the presents of at least four other known markers 5 export the take as a text file from VZsoft Motion Capture Export Data 6 run the MATLAB script getZeroConfig m 7 dont forget to copy and paste the outputted file into the working directory of the GroundStation exe CGZeroConfig txt contains the educated guess of the c g in its initial zero configuration BBFlightArea txt bounding box of the flight area used to neclect data of reflected markers e for temporery changing the host IP address or the port of the UDP bridge the program accepts command line arguments the following usage is recommanded GroundStation exe HostIP UdpPort two examples first one specifies only the host IP address and uses the default UDP port in the second one both values are changed GroundStation exe 192 168 0 117 GroundStation exe 192 168 0 117 15712 e Note the outputted pose
48. t Vicon Motion Capture Systems http www vicon com Documentation Abeje Y Mersha and Riiesch Andreas APPENDIX DOCUMENTATION Contents 1 Brief Introduction 2 LA ate MASERU CIOS e dea oh shes A aa ads BA dd 2 122 Proroga nlos jc crs Se E EE a e a e a 2 Edil Apatety Pilot 4240 04 54 eb aww d hee ek kh eee A Sob de e i 2 1 2 2 Robot Operating System ROS s ae eee eis tontewee dd de dh cas 2 1 3 Versions of used Software Packages 2 a a a a a a 2 LA METIO IN a ot ds en Ge nd ah IIA eee SA eee G 2 2 Overview 4 2 1 Hardware Components 2 2 E LLOSA eee eee EE a 4 ZEL COMPUS E at ara a E RNE 4 Zig Pernpherial i s see eaaa a o A E a ar Bs dba a 5 2 2 Goftware Components s s s sa acesi sdai goie ade ir See a a 5 22d ROS MOJES 44 e RS Shwe oe eee RA a ee da e da 5 2 2 2 Additional Executables aa 6 23 General Remarks uw fe ie hb a sde eos BEER Se AAA 6 3 Hardware 7 ok Force Dimension mec 4 vv kaa e tae eee daa A T D A AS EAN e RS 8 3 2 1 Futaba Remote Control sia ch boy Qk ERA ee eRe AA SO 10 3 3 PTI Visualeyez VZ 4000 Tracker System e 10 4 Software 12 4 1 ROS Package air hapticteleop ciao a A A 12 42 ROS Backase ql lOCCer 4 2 a ts ss E RN E A a a a 13 AD ROS e E fo amp oo ese sind 48 BG eee Ba ee SS 8 A 13 4 4 ROS Package udpoerver 2 s vy eee dees ara DAR aaa 13 45 ROS Message hapticteleop msgs 1 a 14 4 6 MATLAB Simulink target model 8 ee Oe SSE Sole eee
49. t the cor responding markers e Note in a couple experiments the VZSoft crashed when recording data for a long duration about an hour Thus it is recommended to start recording just before the flight experiments e Note2 up until now only the wired capturing of data was possible For some for the author inexplicable reasons the wireless markers did not work August 26 2011 11 Abeje Y Mersha and Riiesch Andreas Documentation 4 Software This section describes the developed ros packages and VZ ground station software The corresponding code APIs are provided in the subfolder doc of the specific package see also Appendix A 1 Furthermore the MATLAB Simulink target model is briefly introduced 4 1 ROS Package air hapticteleop brief summary represents the core package for the haptic teleoperation with the described set up The user s input are mapped to a desired reference position of the slave device furthermore a corresponding force feedback is build and transmitted to the haptic device for displaying purposes The package can be run in different configurations which allow inter alia the prototyping of the teleoperation algorithms in MATLAB Simulink RTW see section 4 6 Furthermore an emulation of the haptic device is provided for tracking of predefined trajectories requirements the ros package requires the following packages to be installed tf roscpp std_msgs geometry_msgs nav_msgs hapticteleop_msgs and asct
50. the VZ software of the tracking system on the Windows ground station by double clicking on the icon 2 Click on the system setting and check if the units of measurement are set correctly in the user option In the current setting it is in mm 3 load up the coordinate frames by clicking on load button Currently the file VZdata coordSyst crf_20110701_01 crf is used for reconfiguration see 4 7 4 Select the TCM8 mode by pressing on the button and select the markers in use Currently markers 1 5 7 8 and 21 32 are in use 5 Click on the record motion green button to start up the tracking system At this point you should be able to see a flickering yellow light at the coordinates system approximately representing the pose of the pelican You can even move the pelican around and observe the corresponding changes in the coordinates system on the VZ soft 6 Click on the pose estimation icon on the windows desktop and check up if the IP address on the tracking system is correct The UAV s IP is static and is currently set to 192 168 0 112 5 1 2 Starting up the Pelican Remark Make sure you to use gloves put on goggles if are in the flying field and or you want to move the pelican by hand while its powered up 1 Switch on the Pelican s FCU and Atom board You should start the FCU on a level ground for calibrated startup of the gyros When you switch on the FCU board you must hear a beeping sound It is highly recommended to read the
51. till are applications where a fully autonomous behaviour is not possible or desirable namely in tasks like e g air surveil lance search and rescue missions or inspection tasks which still require human reasoning or supervision to be success fully accomplished As in the scope of the European project AlRobots 6 within which this work was accomplished the main objective is to develop an aerial inspection robot that interacts with its surrounding under the supervision of a human operator While the operator stays in the control loop and is responsible for the high level tasks he should not be concerned with low level control such as the stabilization of the avionic system itself The UAV should act like a flying hand 6 which is guided by the operator through an interface as natural and intuitive as possible to accomplish high level interaction tasks with the environment In the field of semi autonomous robotics haptic teleoper ation has proved its great potential and benefit of providing major environmental awareness to a human operator while enabling high control accuracy specially in the field of surgical robotics 7 or traditional robotic manipulators 8 Consequently several research groups recently started to investigate the application of haptic teleoperation to aerial vehicles Lam et al 9 11 present a theoretical and ex perimental investigation of the use of wave variables for a This work has been funded by the
52. to a failure of any component the UAV or part of it can move rapidly in any direction Thus it is strongly recommended to perform flight test only within the flight area Furthermore the use of safety goggles and gloves is advised 1 2 Prerequisites 1 2 1 Safety Pilot A safety pilot should always be present and know at least the basic commands to land and turn the UAV off see chapter 3 4 of 4 1 2 2 Robot Operating System ROS The software components presented in the following are written in c and MATLAB Simulink 10 Furthermore ROS 14 is used as a middleware some basic knowledge is presupposed It is highly recommended to at least complete the following tutorials of the ros wiki e Navigating the ROS filesystem beginner level e Creating a ROS package beginner level e Building a ROS package beginner level Understanding ROS nodes beginner level Understanding ROS topics beginner level e Using rxconsole and roslaunch beginner level Running ROS across multiple machines intermediate level 1 3 Versions of used Software Packages Table 1 provides an overview of the versions of the used software packages and tools 1 4 Versioning This manual describes the set up including its software with reference to the revision 87 of the AlRobots SVN UT see also Appendix A 2 NOTE the described set up is currently at an early pre release stage USE AT YOUR OWN RISK ROS Tutorials http www ros org wiki
53. tracker captures the motion of the active markers LED which are mounted on the Pelican The absolute position measurements of those markers are used for the estimation of the UAV s pose Router The Pelican communicates with the ground station through WiFi the ground station and tracker ground station are connected with standard LAN cable to the router A Sitecom wireless gigabit router 300N 16 was used IMPORTANT NOTE the 802 11n standard for the wireless data link is cruical for the success of the flight experiments The network settings are provided in Appendix A 3 2 2 Software Components 2 2 1 ROS nodes air_hapticteleop e Main task runs combined with the MATLAB Simulink Realtime Workshop the master con troller of the teleoperation e Documentation section 4 1 air_logger e Main task logs the flight data for offline analysis e Documentation section 4 2 omega6 e Main task provides an interface for ROS to the haptic device e Documentation section 4 3 udpServer e Main task server of th UDP bridge to the tracker ground station puplishes the received estimation of the UAV s pose within ROS 2Sensable Phantom Omni for this haptic device is a corresponding ros package provided in the svn see Appendix A 2 this package is based on the gt ros pkg of Georgia Tech http www ros org wiki gt ros pkg and adjusted for the purposes of the described set up August 26 2011 5 Abeje Y Mersha and Riies
54. ust the udev default rules in the following manner 1 sudo gedit lib udev rules d 50 udev default rules 2 change the MODE settings to 0666 in the following line libusb device nodes SUBSYSTEM usb ENV DEVTYPE usb_device MODE 0666 e Note that USB 3 0 ports are at least up until now not supported by the Omega6 device link http www forcedimension com download registration required August 26 2011 7 Abeje Y Mersha and Riiesch Andreas Documentation 3 2 AscTec Pelican brief intro an AscTec Pelican quadrotor was used as a miniature flying vehicle for the experiments It is strongly recommended to read the manuals provided by AscTec thoroughly before starting up the robot Some additional information to the platform are given in the following link doc the Pelican including its FCU aka Autopilot are briefly described in 4 the atom carrierboard in 3 The Futaba remote control RC is documented in 9 requirements installation the Pelican is out of the box flyable with the RC the procedure for autonomous resp for haptic teleoperated flights is described in section 5 change log the default settings were adjusted in the following manner 19 04 11 arue installed Ubuntu 10 10 on the Atom s MicroSD according to CCNY wiki gt using the provided customized live CD Ubuntu_10 10_AscTec iso 20 04 11 arue installed wicd to access the eduroam WLAN the following steps are required Not
55. xtended to a larger motion covering larger distances as illustrated at the end of the experiment I I I I 1 47 pos virt mass x pos UAV x altiude m o 00 haptic position m o pos haptic z el I L jl l e an 25 30 35 40 45 Esti ol a o force feedback l gt a 25 time sec state of switch o al T o state l 25 30 35 40 45 time sec Fig 4 Simulation results of the haptic teleoperation with the kinetic scrolling based position mapping Note vertical dashed lines in the top three plots indicate the switching between the two modes Fig 5 shows the effect of the virtual viscous damping coefficient for the same haptic inputs The result shown in Fig 4 was overlayed with the results of simulations with the doubled and halved virtual damping 2H SIM pos virt mass x 1 8 SIM1 pos UAV x 1 6 SIM2 pos virt mass x ____ SIM2 pos UAV x __ SIMS pos virt mass x ____ _ SIM3 pos UAV x A altiude m y fad o e a o P 25 30 35 40 45 time sec Fig 5 Simulation results of the hapt
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