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mrf_thesis - Virginia Tech

1. Message Table 6 3 Machine Synchronization Confirmation Message Field Name Type Units Description 1 Control ID Byte N A Character p designated for ping message 2 Machine Synchronization String N A Link Established Confirmation Message Once the teleoperated machine receives the Remote Station Synchronization Message a Machine Synchronization Confirmation Message is transmitted to the remote station The remote station then waits a specified time clears serial buffers and begins teleoperated control Likewise once the teleoperated machine receives the Machine Synchronization Confirmation Message the teleoperated machine waits a specified time clears the serial buffers and begins teleoperated control The clearing of these buffers ensures that outdated information is removed Figure 6 1 outlines the flow diagram for remote station and teleoperated machine synchronization programs 33 Remote Station Teleoperated Machine Transmit Remote Transmit Teleoperated Station Machine Synchronization Synchronization Message Message Machine Synchronization Confirmation Message Received Execute teleoperated Transmit confirmation message and control mode execute teleoperated control mode Figure 6 1 Synchronization flow diagram Remote Station Synchronization Message Received The remote station and teleoperated machine must send an initial synchronization message in order to r
2. Field Name Type Units Description 1 Control ID Byte N A ASCII character m 6Dh for machine feedback 2 Redundant Emergency Byte N A 0 Emergency stop activated Stop Emergency stop not activated 3 Factory Emergency Stop String N A Provided by Sumitomo Company 4 Water Temperature Byte N A 5 Oil Temperature Byte N A 6 Fuel Level Byte N A 7 Error messages 1 Byte N A 8 Error Messages 2 Byte N A 9 Warning Message s 1 Byte N A 10 Warning Messages 2 Byte N A 6 5 Update Settings Message During preliminary software testing adjustments of the teleoperated machine software required a great deal of time First the software personnel would open the electronics box and connect a computer to the Ethernet hub Next LabVIEW software would connect to the FieldPoint controller Finally the control software could be modified For control software changes to be permanent these settings had to be implemented in hard code Such adjustments required the modified software to be recompiled and embedded into the FieldPoint controller Consequently software was modified to allow the operator to transmit and save machine settings from the remote station Such control allows the remote operator to adjust the following software settings 41 1 2 4 The maximum and minimum reference voltage for each proportional valve Teleoperated machine software cycle rate Frequency of machine feedback transmissions
3. Link e Error Messages e Emergency Stop Switch Controls Status Ignition e Camera power pan tilt zoom focus e Soft emergency stop Figure 5 1 Required control and feedback data for teleoperated control The Hydraulic Controls are considered to be the most critical controls for efficient operation These controls are used to actuate the excavator bucket arm boom swing and tracks The Switch Controls are Boolean controls and have an ON or OFF value Switch Controls govern the remote ignition of the teleoperated excavator the soft emergency stop the power control of all onboard cameras and the pan tilt zoom and focus of the front camera The Machine Feedback indicates the status of the onboard Engine Control Unit ECU and redundant emergency stop 5 2 Communication Structure To ensure real time hydraulic control transmission of the Hydraulic Controls occurs at the highest rate possible while maintaining stable and reliable control Due to the additional bandwidth and time required the protocol does not provide for confirmation of the received Hydraulic Controls data packets Instead a CRC error checking system is implemented to ensure packet integrity see section 5 3 28 Preliminary tests indicated that the operator uses the Switch Controls less frequently than Hydraulic Controls It was also noted that typically the operator does not use the Hydraulic Controls while using the Switch Controls Observations a
4. Sheridan Thomas B and Ferrell W R Man Machine Systems Colonial Press Inc 1974 Cambridge pp 171 174 Fong Terrence and Thorpe Charles Vehicle Teleoperation Interfaces Autonomous Robots Vol 11 2001 pp 13 Ferrell William R Remote Manipulation with Transmission Delay JEEE Transactions On Human Factors in Electronics No 1 Sept 1965 Sheridan T B Human Enhancement and Limitation in Teleoperation Progress in Astronautics and Aeronautics Vol 161 1994 pp 71 79 Sheridan T B Human Supervisory Control of Robot Systems IEEE International Conference Vol 3 April 1986 pp 808 National Instruments Corp 2003 FieldPoint Family Distributed I O Available hitp www ni com DO November 2003 46 14 15 16 17 18 19 Data Linc Group 2003 SRM6000 900MHz Frequency Hopping Spread Spectrum Radio Modem Available h p www data linc com products htm P0 November 2003 Futaba Industrial Radio Controls 2002 6 Channel 1 Analog Long Range ele eries Available e htm DO November 2003 Case Construction Co 2003 CX 160 tracked excavators Available tp www casece com P0 November 2003 Travis Jeffery LabVIEW for Everyone Prentice Hall Upper Saddle River 2002 National Instruments RT Engine User Manual April 2001 Eagle Systems CRC Generating Example 1999 pp 1 47 Vita Michael Ryals Fleming was
5. Arm Byte Scaled Integer Lower Limit 100 Upper Limit 100 4 Boom Byte Scaled Integer Lower Limit 100 Upper Limit 100 5 Swing Byte Scaled Integer Lower Limit 100 Upper Limit 100 6 Left Track Byte Scaled Integer Lower Limit 100 Upper Limit 100 7 Right Track Byte Scaled Integer Lower Limit 100 Upper Limit 100 When the teleoperated machine receives the Hydraulic Control message the reference voltage to the open and close proportional valves for each hydraulic actuator is calculated For zero or positive integer hydraulic control values Heontoi20 the reference voltage for the hydraulic proportional values is calculated as shown in equation 6 7 It is assumed that the absolute value of Hcontror cannot be greater then 100 due to constraints within the remote station software Vus m B controt Wa open V open control max open min open for 100 gt LH oin gt 0 6 7 close where V open is the reference voltage in volts of the hydraulic open proportional valve V 455 is the reference voltage in volts of the hydraulic close proportional valve V max open iS the maximum voltage of the hydraulic open proportional valve V min close 18 the minimum voltage of the hydraulic open proportional valve For negative integer hydraulic control values Heontror lt 0 the reference voltage for the hydraulic proportional values are calculated as shown in equati
6. Computational and control hardware should be capable of executing developed software and expanding for future software development The telemetry solution must be capable of supporting system bandwidth and be resistant to interference The operator must have an understanding of the work environment in order to make control decisions Thus sensors need to be placed on the vehicle or at the work site Sensor information must then be relayed to the operator and displayed in a useful fashion Sensor selection placement and display are critical to the operator s understanding of the work environment and task efficiency All hardware components onboard the teleoperated machine must be resistant to heat and cold weather vibration and other elements associated with machine operation and its work environment Therefore it is important that durable hardware is selected and appropriate measures are taken to protect the equipment from damage Due to the dangerous UXO work environment safety features should be implemented in the teleoperated design to isolate system failures Safety systems should be reliable independent and tested to ensure functionality at all times Chapter 2 Literature Review For this thesis vehicle teleoperation will be defined as operating a vehicle at a distance see figure 2 1 Furthermore the spectrum of teleoperated control will encompass direct coordinated and supervisory control Control is always necessary
7. Maximum time of delay between received data packets before failsafe mode is activated The developed software allows the operator to adjust machine software settings in near real time The operator updates machine settings through the remote station graphical user interface After the operator adjusts and saves the setting the settings are transmitted and updated on the teleoperated machine These settings remain in effect for future operation Once the operator adjusts and saves the Machine Settings the Machine Settings message can be compiled The ASCII character c 63h will represent the Machine Settings message identifier The minimum and maximum voltage settings for each proportional valve the cycle rate at which the machine software executes the update rate at which the unconfirmed feedback control string is transmitted and the failsafe mode timeout will respectively follow the message identifier as shown in table 6 7 42 Table 6 7 Machine Settings Message Field Name Type Units Description 1 Control ID String N A ASCII character c for changing the machine settings 2 Minimum Voltage Bucket Open Single Volts Proportional valve voltage for 1 bucket open operation 3 Maximum Voltage Bucket Open Single Volts Proportional valve voltage for 100 bucket open operation 4 Minimum Voltage Bucket Closed Single Volts P
8. Ratio If this information were made available developed software could interpret it and provide the operator with telemetry link quality in the graphical user interface GUI It is suggested that future use of this design request SRM 6000 firmware that provides link status and signal quality feedback VSD 2002 Emergency Stop In order to ensure that the operator can place the teleoperated excavator in a motionless state the Futaba Industrial Radio Control VSD 2002 system was incorporated into the teleoperated control design as a redundant emergency stop The VSD 2002 uses frequency hopping spread spectrum FHSS technology in the 900 MHz band to communicate up to 1 mile 15 TUS Figure 3 5 Futaba Industrial Radio Control VSD 2002 15 13 An emergency stop function is incorporated in the VSD 2002 If the operator activates the emergency stop or if the connection between the transmitter and receiver is lost a relay on the VSD 2002 receiver disengages This renders the hydraulic system without power and places the excavator into a motionless state 3 2 Remote Station The remote station houses the operator and teleoperated controls For safety the remote station should be located in a protected area The remote station shown in figure 3 6 is approximately 1500 feet from the teleoperated machine and is housed in a thick walled steel building Based on preliminary tests the teleoperated excavator can be operated remotely up to 3
9. Volts Proportional valve voltage for 100 left track forward operation 20 Minimum Voltage Left Track Reverse Single Volts Proportional valve voltage for 1 left track reverse operation 21 Maximum Voltage Left Track Reverse Single Volts Proportional valve voltage for 100 left track reverse operation 22 Minimum Voltage Right Track Single Volts Proportional valve voltage for 1 right track Forward forward operation 23 Maximum Voltage Right Track Single Volts Proportional valve voltage for 100 right Forward track forward operation 24 Minimum Voltage Right Track Single Volts Proportional valve voltage for 1 right track Reverse reverse operation 25 Maximum Voltage Right Track Single Volts Proportional valve voltage for 100 right Reverse track reverse operation 26 Machine Program Cycle Rate Word Hz Cycle speed of the software program on the machine controller 27 Update Rate of Machine Feedback Word Hz Rate at with the machine feedback telegram is transmitted 28 Data Read Timeout Failsafe Word ms Length of delay in received data before failsafe mode is activated 43 Chapter 7 Conclusions Traditionally modifying hydraulic equipment to allow teleoperation has been an expensive and lengthy process This research has demonstrated that by incorporating off the shelf technology into a modular design teleoperated equipment can be developed rapidly and inexpensively Within six months and a hardware cost of 20k a group of Vir
10. b stationary rear camera The teleoperated machine graphical user interface GUI displays information pertaining to the excavator s on board systems This information includes the 1 operator hydraulic control for each hydraulic actuator 2 current voltage to the open and close proportional valve for each hydraulic actuator 3 state of each discrete control such as camera power and engine ignition While the teleoperated machine GUI is not viewed or accessed by the remote operator it provides a quick reference for on site software debugging Figure 3 13 shows the teleoperated machine graphical user interface 20 BEES SES EES mg E Er D Figure 3 13 Teleoperated machine software interface 1 operator control for each hydraulic actuator 2 voltages to proportional valves 3 status of teleoperated machine software 4 confirmation of updated machine feedback 5 link status between the remote station and the teleoperated machine 6 switch control status 2 Chapter 4 Software Development Pursuant to customer request all software was developed in National Instruments LabVIEW The preference for LabVIEW development stemmed from the confidence and knowledge gained through previous successes and experiences with this software package Additionally prior experience provided immediate technical expertise in software development as well as in future expansion of developed software This section presents an overview o
11. born 29 September 1978 to Roger and Marilyn Fleming of Bluefield West Virginia He graduated from Princeton Senior High School in 1997 and enrolled in Virginia Polytechnic Institute and State University Virginia Tech As an undergraduate he complete one year of cooperative education with International Paper Michael Fleming graduated with a BS in Mechanical Engineering in 2002 He continued his studies at Virginia Tech and graduated with a MS degree in Mechanical Engineering in 2003 48
12. pedal controls 3 errors or warning on the CX 160 Engine Controller Unit 4 telemetry link status between the remote station and teleoperated machine 5 confirmation of updated switch controls 6 status of the soft emergency stop 3 3 Teleoperated Machine Conventional on board operation of the CX 160 hydraulic controls is achieved through two dual axis joysticks and two single axis foot pedals These devices mechanically control pressure to operate a 500 psi hydraulic pilot system The pilot system then actuates a spool valve which in turn supplies directional control of the 5500 psi main hydraulic system The main hydraulic system then actuates the hydraulic cylinders As shown in figure 3 10 the CX 160 excavator has six hydraulic degrees of freedom bucket arm boom swing left track and right track 17 ey y A L Left Track E Fight Track 1 Figure 3 10 Case CX 160 degrees of freedom 16 A parallel hydraulic system was integrated into the CX 160 pilot hydraulic system for by wire control Shuttle valves are used to tie the parallel hydraulic system into the 500 psi pilot system Electro proportional valves are placed in the parallel hydraulic system in order to control hydraulic flow These proportional valves are open loop solenoid operated pressure reducing control valves Tying into the 500 psi system provides lower flow rates and a safer alternative then tying into the 5500 psi system This desi
13. to develop standards in the unmanned community such as the Joint Architecture for Unmanned Systems JAUS While still in its infancy the JAUS architecture is focused on developing standards in unmanned systems while still allowing vehicle mission hardware and technology independence If future development of the outlined teleoperated system incorporates higher levels of control and automation it is recommended that the JAUS standard is adopted 45 References 1 2 3 4 5 6 7 8 9 10 11 12 13 Tucker R L Construction automation in the USA Proceedings of 16 International Symposium on Automated Robotics Construction Madrid Spain 1999 pp vii Terwelp C R Remote Control of Hydraulic Equipment for Unexploded Ordnance Remediation Masters Thesis Virginia Polytechnic Institute and State University May 2003 Kelley Charles R Manual and Automatic Control A Theory of Manual Control and its Application to Manual and to Automatic Systems John Wiley amp Sons Inc 1968 New York pp 176 177 Buggy Available Abu 19 October 2003 Omnitech Robotics Standardized Teleoperation System STS Brochure 2001 pp 3 4 Omnitech Robotics Standard Teleoperated System STS Applications Available h tp Awww omnitech com sts htm 23 October 2003 Robotech Industries What is a HazHandler Available hfip www unbound November 2003
14. 000 ft line of sight from the remote station If desired increased transmission power and directional antennas can provide greater operating distances Figure 3 6 Remote station in Dahlgren VA The remote station FieldPoint system reads analog voltages produced by joysticks and pedals through a FP AI 100 module The FieldPoint controller reads discrete voltages produced by the switch controls through a FP DI 300 module Custom developed software is used to package this information into custom formatted data packets These packets are then transmitted to the teleoperated machine through the 14 SRM 6000 wireless radio modems The remote station SRM 6000 also receives feedback information from the teleoperated machine This feedback information provides the operator with the status of the Engine Controller Unit ECU and the VSD 2002 emergency stop on the teleoperated machine The operator controls and teleoperated machine feedback are then displayed on a graphical user interface GUI Figure 3 7 is the remote station hardware flow diagram Operator Interface Link to teleoperated Packaged machine Data FP 2000 SRM 6000 Figure 3 7 Remote station hardware flow diagram The remote station was designed to replicate the controls within the CX 160 excavator cab and to provide the operator with a comfortable operating environment In this replication two dual axis joysticks two single axis foot pedals and switch controls ar
15. 18 the voltage output of the joystick or pedal axis in volts Vero is the voltage where Hoi 0 in volts V min is the voltage where Hei 100 in volts V min is the voltage where Heontroi 100 in volts In preliminary tests it was observed that when the joystick and foot pedals were at a centered state fluctuations in the joystick and pedal reference voltages caused a non Zero H Value As a result either the open or close hydraulic proportional values were needlessly energized To eliminate this problem a dead band feature was incorporated into the scaling of each joystick and pedal control As a result if the joystick or pedal control voltage falls within the dead band zone a zero percent control value is calculated By incorporating dead band in the calculations Vzero is recalculated as Vdeadband in equations 6 3 and 6 4 H for Vioystick gt Vzeroz0 6 3 zero Deadband E E IS p Vs Iud 100 Deadband y y Cro ps V nin deadband ze 1 00 for Faso gt V joystick 20 6 4 where Deadband is the dead band of a control in percent The developed software allows each joystick and pedal control to have a unique dead band percent Vmax Vzero and Vmin setting By substituting equations 6 3 and 6 4 35 into equations 6 1 and 6 2 the scaled hydraulic control values with dead band can be calculated as shown below V nua V Joystick deadband E 100 for Vioystick gt Vzero gt 0 6 5 max deadba
16. Being part of this project has been one of the most challenging and rewarding opportunities I have had at Virginia Tech The completion and success of this project would not have been possible without the contributions of each team member and support from the Virginia Tech Mechanical Engineering department I would like to start by thanking Dr Charles Reinholtz for serving as my committee chairman and advisor His devotion to the students is evident by the constant student line outside his office With his many accomplishments the respect and time he demonstrates towards his students is admirable It has been a pleasure working with you This project would not have been possible without the relationship between Dr Al Wicks and NSWC DD From managing the project to turning wrenches he has continuously demonstrated his commitment to the project s success without ever taking credit While I am still not fond of the 5 00 AM trips I will miss the trips to Shoney s and Sheetz I would like to thank Dr Harry Robertshaw for serving on my committee His spearheading efforts to bring hands on learning into the ME Lab classes provided me with a foundation in DAQ and LabVIEW that were instrumental to the success of this project I would like to particularly thank Chris Terwelp and Ian Hovey for their countless hours implementing the hydraulic and electrical systems The project s success is evident in their attention to detail and drive for success I espe
17. OS utility PING Packet INternet Groper The PING utility transmits small packets of data to a particular IP Internet Protocol address The computer that sent the PING packets then waits and listens for a response If a complementary packet is received by the originating computer a communication link exists between the two computers Otherwise a communication link does not exist between the computers During synchronization the teleoperated machine transmits the Teleoperated Machine Synchronization Message and the remote station transmits the Remote Station Synchronization Message at set intervals see table 6 1 and 6 2 Between each transmission the teleoperated machine listens for a Remote Station Synchronization Message and the remote station listens for a Machine Synchronization Confirmation Message see table 6 3 If a message is not received a communication link does not exist and the process repeats 32 Table 6 1 Remote Station Synchronization Message Field Name Type Units Description 1 Control ID Byte N A Character p designated for ping message 2 Remote Station String N A Remote Station Link Synchronization Message Request Table 6 2 Machine Synchronization Message Field Name Type Units Description 1 Control ID Byte N A Character p designated for ping message 2 Machine Synchronization String N A Machine Link Request
18. Perit arid rir hes gl berg thant Ie ee eared nati tech rat Grii the reer signa inpr is eat ba Figure 4 1 Front panel of Function Waveform Generation vi The other component a block diagram contains the VI graphical source code LabVIEW source code consists of graphical blocks compiled into flow diagrams LabVIEW provides standard graphical blocks in the functions palette that can be selected and placed in the block diagram These blocks may vary from simple functions such as addition or subtraction to more complex functions such as the Fast Fourier Transform FFT If a required function is not available in the functions palette a subprogram or sub VI can be created from existing functions Once created the sub VI can be selected from the functions palette and placed in the block diagram Figure 4 2 shows the functions palette and the block diagram for the Function Waveform Generation vi 23 Functions Palette i Function Waveform Generation wi Block Diagram i E J f E Eie E porse Tous Droese Window E Ze n cil leletior eege EISE FM Ir Ei phase cur un Figure 4 2 Block diagram of the Function Waveform Generation vi Being hierarchical and modular VI s can be used as top level programs or subprograms With such architecture LabVIEW promotes the concept of modular programming Modular programming divides programs into a compilation of simpler and more manageable programs This approach pro
19. Teleoperated Control of Hydraulic Equipment for Hazardous Material Handling by Michael Ryals Fleming Thesis submitted to the Faculty of the Virginia Polytechnic Institute and State University in partial fulfillment of the requirement for the degree of MASTERS OF SCIENCE IN MECHANICAL ENGINEERING Dr Charles F Reinholtz Chairman Dept of Mechanical Engineering Dr Alfred L Wicks Dept of Mechanical Engineering Dr Harry H Robertshaw Dept of Mechanical Engineering December 4 2003 Blacksburg VA Keywords Teleoperate Remote Control Hazardous Material Excavator Hydraulics LabVIEW Teleoperated Control of Hydraulic Equipment for Hazardous Material Handling Michael Ryals Fleming Abstract Traditionally teleoperation has been an expensive and lengthy process This thesis shows that by incorporating off the shelf technology into a modular design teleoperation can be developed rapidly and inexpensively Within six months and a hardware cost of 20k a group of Virginia Tech students and faculty converted a Case CX 160 excavator to teleoperated control With full wireless functionality of the excavator s six degrees of freedom ignition and remote cameras at 3000 ft the teleoperated design meets or exceeds customer demands For over a year the teleoperated excavator has demonstrated effectiveness robustness and durability in multiple unexploded ordnance UXO site remediation projects Acknowledgements
20. ard ram the WD liste that Hu Les k nn cad ne rum until tee mint sire tin se lr Figure 4 4 The Function Waveform Generation vi Web server interface 26 Chapter 5 Communication Protocol The project scope for software development encompasses three major areas interpreting control and feedback information relaying information to desired destinations and appropriately interpreting and executing received information Software structure and optimization are critical to ensuring rapid development and reliable real time control To ensure reliable real time direct control a custom communication protocol was developed for data transmission between the remote station and the teleoperated machine Protocol development defines the data structure of transmissions the appropriate times for data transmissions and the failsafe measures necessary in the event of a communication failure 5 1 Teleoperated Controls and Feedback Advice from experienced machine operators assisted in the composition of necessary teleoperated operator controls and feedback Figure 5 1 shows the list of these controls and feedback broken down into three categories 1 Hydraulic Controls 2 Switch Controls 3 Machine Feedback 27 Remote Station CX 160 Excavator Hydraulic Controls Bucket e Boom Machine Feedback e Arm e Fuel Level e Swing Oil Temperature e Left Track Wireless e Water Temperature e Right Track Communication Warning Messages
21. are design using off the shelf technology was adopted to expedite development simplify debugging and allow for future expansion In addition this design can be replicated for use on similar hydraulic machinery The CX 160 excavator shown in figure 3 1 was converted to teleoperation within six months at a hardware cost of less then 20k This chapter provides an overview of the hardware design for converting a Case CX 160 excavator to teleoperated control Figure 3 1 Teleoperated CX 160 excavator 3 1 Computation and Telemetry This section provides an overview of the computational and telemetry off the shelf components used in the hardware design of the teleoperated excavator Based on the standalone operation compact size and industrial grade reliability the National 10 Instruments FieldPoint FP product line was chosen to execute developed LabVIEW software for the control of the CX 160 teleoperated excavator With a 115 2 kbps throughput the Data Linc SRM 6000 wireless serial modem was implemented to transmit data between the FieldPoint systems at the remote station and teleoperated machine The Futaba VSD 2000 emergency stop system was selected as a redundant failsafe system FieldPoint The National Instruments FP 2000 controller was chosen for standalone software execution at the remote station and the teleoperated machine The FieldPoint controllers contain a real time LabVIEW embedded controller for intelligent control
22. but circumstances often warrant teleoperation Teleoperation is often implemented in difficult to reach environments to improve task efficiency and to reduce human risk 3 Human Operator Barrier Telerobot Local Loop lt Sensor Feedback Information Remote Loop Figure 2 1 Vehicle teleoperation An operator at a control station generates commands and receives feedback from remote sensors The vehicle executes the operator commands Vehicle teleoperation differs from remote control operations i e line of sight operation in several aspects Since teleoperated vehicles are often deployed in unknown unstructured and dangerous environments potential system losses make robust operation imperative And since task performance is directly correlated to system control vehicle teleoperation requires efficient motion command generation Also vehicle teleoperation requires localized sensor data which can then be relayed to the operator for decision making 2 1 Teleoperated Ground Vehicles Vehicle teleoperation first appeared in the early 1900 s but it was not until the 1970 s that systems became widely used Today vehicle teleoperation is in air space ground and underwater applications Since teleoperation development occurred over different periods and in different environments vehicle teleoperation is referred to by numerous terms including ROV Remotely Operated Vehicles RPV Remotely Piloted Vehicles UAV Unmanned Air Veh
23. cially appreciate their assistance in enduring the painstaking task of optimizing software settings during those late nights I would like to thank George Clotfelter for his support even after I erased the excavator ECU Ialso appreciate you putting me up for a night when the software upgrade didn t go as smooth as I claimed I would also like to thank the National Instruments support of Brian MacCleery and Eric Dean for their technical expertise that I heavily relied upon Most importantly I would like to thank my non technical family who has had to deal with my engineering mishaps over the years You have always supported me even when I took out all the televisions by transmitting 1 kW over the airwaves iii This page left intentionally blank iv Table of Contents Chapter 1 Introduction EE l l l Project Overview a eaa Es E OE PU PAR D UR Es apa sa estes 1 1 2 Technical challenges i o xdi beoe EE ee tts 2 Chapter 2 Literature Review 4 2 1 Teleoperated Ground Vehicles genge root EA deed EENS E 4 2 2 Control Method EE 8 Chapter 3 Overall Design nee rtr UR EU ER FURY VOLU GE 10 3 1 Computation and Telemetry EEN 10 3 2 R mot TE ee UE D T 14 3 3 Teleoperated EE 17 Chapter 4 Software Development 22 EE 22 ARE Lime ERNST SEIT LUTEA e 25 4 3 Mee ee eege 25 Chapter 5 Communication Drotocol ken ena ener 27 5 1 Teleoperated Controls and Feedback 2T 5 2 Communication Strutter desee ee 28 Sa Felesram F
24. cter based on the unlikelihood that it would be contained in any other component in the telegram Second the Message Length is an unsigned 8 bit value representing the number of bytes contained in the Message The Message Length represents values from 1 to 255 Based upon the scope of this project it is not anticipated that messages will be greater 30 then 255 bytes long If future use of this architecture requires larger Message sizes an unsigned 16 bit value can be implemented for the Message Length An unsigned 16 bit Message Length can contain values up to 2 65536 Third the Message field contains a predefined set of information pertaining to the control of the teleoperated machine The Message includes an identifier which indicates the type of message followed by associated data see section 7 2 The structure presented here builds a foundation for integration of future Message types Finally the Cycle Redundancy Check CRC is a mathematical method of validating data integrity CRC interprets blocks of message bits as coefficients for polynomials For instance the binary number 10100000 implies the polynomial 1 x O x L3 0 x 0S8 0 x 0 x 0 x This value is the message polynomial A second polynomial with constant coefficients is called the generator polynomial The generator polynomial is divided into the message polynomial rendering a quotient with a remainder The coefficients of the remainder form the bi
25. e placed in locations similar to the corresponding controls in the cab The operator chair can accommodate a variety of operators with chair height adjustments and with joystick height and rotation adjustments Preliminary tests indicated that the joystick and the camera pan tilt and zoom controls were the most frequently used controls As a result these camera controls were incorporated in the thumb and trigger buttons on each joystick Such integration allows the operator to actuate the joystick and camera functions without having to release the joystick controls The operator console is shown in figure 3 8 15 Graphical User Interface m ER X Remote E camera Sei ro displays E i j E Rd I mn fl Operator Chair Pedal Controls R Figure 3 8 Operator console The remote station graphical user interface GUI displays the teleoperated machine feedback and current controls on a computer screen as shown in figure 3 9 This information is viewed through a standard Web browser connected via Ethernet to the FieldPoint controller see section 4 3 The GUI allows the operator to modify settings such as joystick pedal and proportional valve voltage settings Adjustment to these settings are saved and updated in real time see section 6 2 16 Figure 3 9 Operator graphical user interface 1 water temperature hydraulic temperature and fuel level of the CX 160 2 current joystick and
26. ed CX 160 It had to be capable of 1 operating at a maximum distance of 3000 ft 2 converting from manual to remote operation in less then three minutes 3 providing safe and efficient operation and 4 being delivered within six months Figure 1 1 shows the excavator along with the team of Virginia Tech faculty and students NSWC DD engineers and Case personnel assembled to tackle this task Figure 1 1 Case CX 160 and team members 1 2 Technical Challenges Converting a 16 ton hydraulic excavator to teleoperated control presents a variety of technical challenges Design decisions associated with by wire hydraulic control software development telemetry operator feedback system durability and safety significantly impact project success Improper modification of high pressure hydraulic systems may result in human injury and machine damage Therefore safety is a high priority when working with hydraulic components The proper selection and placement of hydraulic components is critical to optimal by wire control Consequently hydraulic system flow rates pressures and system response require close attention 2 Robustness and optimization in software design are essential to reliable real time control Software development must resolve errors and failures while still maintaining stability and functionality Control data must be sampled packaged transmitted deciphered and executed efficiently frequently and with minimal delay
27. eee 44 Chapter 1 Introduction The purpose of this document is to explore cost effective methods for converting manually operated hydraulic equipment to teleoperated control Traditionally teleoperation has been an expensive and lengthy task 1 This document presents methods of using off the shelf technology to retrofit a Case CX 160 hydraulic excavator to teleoperated control The design presented in this thesis demonstrates that teleoperated hydraulic equipment can be developed rapidly and inexpensively The teleoperated CX 160 was developed for the Naval Surface Warfare Center in Dahlgren VA to excavate buried unexploded ordnance UXO While this design is focused on UXO excavation it is applicable in other hazardous material handling applications In addition the developed teleoperated system provides a foundation for future work such as coordinated control and automation 1 1 Project Overview In February 2002 the Naval Surface Warfare Center in Dahlgren VA NSWC DD and the Mechanical Engineering department at Virginia Tech embarked on a project to develop a teleoperated system capable of unearthing buried unexploded ordnance UXO With a delivery time of six months it was decided to retrofit an excavator to teleoperation Considering the large area to be excavated and the potential for finding heavy buried UXO a 16 ton Case CX 160 excavator was selected for the task NSWC DD mandated four specific requirements for the teleoperat
28. ehicles to remote control and teleoperated control One such system is the Standard Teleoperation System STS The STS kit consists of modular components for converting a variety of vehicles to remote control and teleoperated control As shown in figure 2 3 the STS system includes 1 Operator Control Unit 2 Vehicle Control Unit 3 High Integration Actuators 4 Safety Radio Transmitter 5 System Input Output and 6 Video Transmitter Unit 5 Figure 2 3 ORILLC Standard Teleoperation System STS 1 Operator Control Unit 2 Vehicle Control Unit 3 High Integration Actuators 4 Safety Radio Transmitter 5 System Input Output 6 Video Transmitter Unit 6 The Operator Control Unit OCU provides the operator with remote vehicular control The OCU includes a radio transceiver operator controls video display and an instrument panel The Vehicle Control Unit VCU is a modular device that controls the central control computer and all control interfaces for the STS vehicle The VCU uses a serial control bus and CAN interface to communicate with all the peripheral control components The High Integration Actuators HIA govern the vehicle operator controls such as throttle braking and steering The HIA interfaces with motor potentiometer feedback optical encoder load cell temperature sensors servo power amplifiers and CAN interfaces With different interfaces the HIA can be fitted with an array of control components a
29. erated machine The teleoperated machine then executes this control within an onboard control loop Coordinated control is used to close control loops that the operator is unable to control due to delay However coordinate control does not include any level of autonomy at the controlled machine Supervisory Control Over forty years ago Sheridan coined the term supervisory control for a control exercised by an intelligent controller under human supervision 11 In supervisory control systems the operator compiles a set of tasks for machine execution Throughout execution the operator reprograms and monitors intermittent feedback to ensure safe and proper operation Such standalone operation requires some level of machine intelligence At any point the human operator has the option to take on a greater level of control for either routine or emergency situations The principal advantages of supervisory control over direct control are 1 quicker task completion time 2 quicker response time to unexpected events 3 greater control accuracy 4 the ability to perform long duration tasks without continuous human attention 12 Chapter 3 Overall Design After reviewing the design requirements and surveying the existing commercial solutions the design team decided to develop a new teleoperated excavator The new system which is described in this thesis meets or exceeds all customer specifications previously described A modular hardw
30. esolve communication failures at either end For instance assume that the teleoperated machine is in a synchronization mode and that the remote station is in a teleoperated control mode The teleoperated machine would then be waiting on a synchronization message The remote station being in a teleoperated control mode would be transmitting control messages and would not recognize that the teleoperated machine is awaiting a synchronization message To avoid such a scenario the remote station and the teleoperated machine each send a synchronization message 6 2 Hydraulic Control Message The control signals for the teleoperation of the CX 160 bucket arm boom swing and tracks are produced by output voltages from electronic joysticks and pedals see section 3 2 Developed LabVIEW software is used to scale these joystick voltage outputs to a 34 positive or negative percent Accordingly 100 Vmin represents the maximum closing rate of a hydraulic cylinder 0 Vero represents no hydraulic actuation and 100 V max represents the maximum opening rate of a hydraulic cylinder The following equations were used in preliminary testing to calculate the linearly scaled control value for the excavator hydraulic controls V ond T Vs H GER 100 v y for Vioystick gt Vzeroz0 6 1 E Ge E H od 100 vV o y for Vero gt V ioystick 20 6 2 where Hoontrot 18 the scaled hydraulic movement rate in percent from 100 to 100 V joystick
31. f the LabVIEW programming environment the Real Time Engine and the Web Server used to execute and monitor the deployed software for the teleoperated control of the CX 160 excavator 4 1 LabVIEW LabVIEW Laboratory Virtual Instrument Engineering Workbench is a graphical programming language that has been widely adopted throughout industry academia and research labs as the standard for data acquisition and instrument control software 17 In order to expedite software development LabVIEW uses terminology icons and ideas familiar to scientists and engineers In contrast to other programming platforms which typically use text based languages to create line of code LabVIEW uses a graphical interface to create programs in a pictorial form Developing software in graphical form places the programmer s primary focus on dataflow rather than on syntactic details A developed LabVIEW program is referred to as a virtual instrument VI A VI consists of two main components a front panel and a block diagram The front panel serves as an interactive graphical user interface GUI Front panels can contain controls such as knobs and push buttons as well as indicators such as graphs and text displays Figure 4 1 shows a LabVIEW sample program for generating and displaying a waveform 22 Er Peat heen Weestomm Ceres pation i Fret Fare De SE pee oom poe m T Fd e a lee Application Fori Controls Indicator the inputs ta the dearer
32. for controller and module connectivity While the compact FieldPoint product line was available during project development it is suggested that future use of this design incorporate the compact FieldPoint components SRM 6000 Serial Radio Modems The Data Linc SRM 6000 wireless serial modems were chosen to relay data between the FieldPoint systems at the remote station and teleoperated machine With serial connectivity the radio modems and FieldPoint controllers connect and exchange data through RS 232 ports The Data Linc wireless radio modems provide a 115 2 kbps data throughput up to 25 miles line of sight using omni directional antennas assuming 75 frequency availability The SRM 6000 employs frequency hopping spread spectrum FHSS technology in the 900 MHz ISM industrial scientific medical band A 32 bit Cycle Redundancy Check CRC error correction is used to verify transmitted packet integrity If a corrupt packet is received a retransmission of that packet is requested 14 The radio modem CRC feature was disabled for this project Instead error correction is implemented in the communication protocol as outlined in section 5 3 12 Figure 3 4 Data Linc SRM 6000 wireless serial modem 14 The SRM 6000 provides external lights indicating when another SRM 6000 radio modem is detected and when data is being exchanged However there are no provisions for the transmission of link status and signal quality 1 e Signal to Noise
33. ginia Tech students and faculty converted a Case CX 160 excavator to teleoperated control With full wireless functionality of the excavator s six degrees of freedom ignition and remote cameras at 3000 ft the teleoperated design meets or exceeds customer demands For over a year the teleoperated excavator has demonstrated effectiveness robustness and durability in multiple UXO site remediation projects Figure 7 1 Teleoperated Case CX 160 excavator in operation With a low development cost and modular design government agencies and companies can benefit by equipping hydraulic equipment with the presented teleoperated system This design is applicable to a wide range of devices where manually controlled hydraulic systems operate in dangerous work environments Hydraulic machine manufactures can also benefit from this design by incorporating modular low cost teleoperated features into manual equipment The design methodology provides an 44 additional resource for ongoing research in the automation of hydraulic systems The presented direct control system lays the foundation for higher levels of control and automation such as coordinated and supervisory control These technologies have the potential for greater productivity and cost savings The Joint Robotics Program JPR is focused on supporting and developing technologies to facilitate the development of unmanned systems As a leader in unmanned systems JPR has taken the initiative
34. gn allows in cab manual or teleoperated control without any modifications For further details in the hydraulic design of the teleoperated CX 160 see Terwelp 2 The SRM 6000 radio modem on the teleoperated machine is used to receive operator control information and to transmit machine feedback information Once the operator control information is received the FieldPoint controller deciphers this information The controller then outputs the corresponding reference voltages to the proportional controllers in the parallel hydraulic system through FP AO 210 modules Similarly the controller outputs the relay state for the switch controls through FP RLY 410 modules The on board Engine Controller Unit ECU was modified by Sumitomo to output ECU status through an unused RS 232 port A second FP 2000 controller was 18 placed on the teleoperated machine to read the ECU serial data The second FP 2000 controller transmits ECU feedback to the main FP 2000 controller through an Ethernet connection Updates in the ECU status are then packaged and transmitted to the remote station for operator display It is recommended that future use of this design incorporate the new compact FieldPoint product line which contains controllers with multiple serial ports A controller with two serial ports can connect to the RS 232 port on the serial modem and the ECU This eliminates the need for a second FP 2000 controller The flow diagram for the teleoperated machine ha
35. icles and UGV Unmanned Ground Vehicles The first two abbreviations clearly refer to teleoperated systems while the last two encompass both teleoperated systems and autonomous systems Because there are such a variety of teleoperated systems the following section will outline several teleoperated ground vehicle systems for use in military and industrial applications The components and features of the SPARWAR Advanced Teleoperated Technology ATT Omnitech Standard Teleoperation System STS and Robotec Operating Platform for Unmanned Vehicles Systems OPUS are summarized below Space and Naval Warfare Systems Command SPAWAR In 1982 the Advanced Teleoperator Technology ATT Teleoperated Dune Buggy was developed to focus on teleoperator control methodology It demonstrated that remotely operated ground vehicles could be driven in complex natural terrain This technology incorporated stereo head couple visual displays binaural audio feedback and controls similar to those on the vehicle Particularly the ATT effort demonstrated the efficiency of stereo head coupled visual display systems binaural audio feedback and isomorphic vehicle controls for high speed remote vehicle operations 4 E T i a SD E mie WE A Clg VK Figure 2 2 Teleoperated dune buggy 4 Omnitech In cooperation with the Joint Robotics Program JRP Omnitech Robotics International LLC ORILLC developed several systems for converting ground v
36. llowing it to be adapted to a variety of vehicles Nearly 60 vehicles are equipped with STS kits for unmanned operation including tanks tractors High Mobility Multipurpose Wheeled Vehicles HMMWV Skytrak forklift all terrain vehicles ATVs and trucks see figure 2 4 These remote control and teleoperated control vehicles are being used in applications such as construction mining counterterrorism explosive ordnance handling disposal fire fighting and hazardous material handling 6 b Figure 2 4 Omnitech teleoperated systems a teleoperated John Deer T3 tractor b High Mobility Multipurpose Wheeled Vehicle HMMWV 6 Robotec Since 1992 Robotec has provided remote control and teleoperated systems for the military industry and research applications The HazHandler product was developed to convert Bobcat machinery into remote control and teleoperated control As shown in figure 2 5 Robotec has developed custom control systems termed the Operating Platform for Unmanned Systems OPUS and Vehicle Network for Unmanned Systems VeNUS These systems are embedded micro controller based systems using off the shelf components Some of the HazHandler features include emergency shutdown controls on the remote console and on all sides of the vehicle a joystick deadman feature which places the vehicle in standby mode when the joystick handle is not pressed and communication and command verification before vehicle movement Upo
37. lso revealed that the Machine Feedback status seldom changes therefore it does not require frequent updates Consequently the Switch Controls and Machine Feedback are transmitted only when a change is detected Upon a detected change the message continues to transmit until the receipt of a confirmation message matches the transmitted message Remote Station Hydraulic Controls Continuously transmit control packets at desired rate Switch Controls Upon control change transmit packet until confirmation is received Machine Feedback Update operator display and transmit confirmation packet Hydraulics Actuators Actuate hydraulics based on received data Switch Controls Update switch based controls and transmit confirmation packet Machine Feedback Upon feedback change transmit packet until confirmation is received Figure 5 2 Communication protocol for teleoperation of CX 160 Preliminary tests indicated the criticality of the rate at which the Switch Controls and Machine Feedback messages were transmitted prior to confirmation Closer inspection determined that these messages were transmitted too quickly causing multiple identical messages to be transmitted before confirmation could be received The increased bandwidth and additional processing caused system delays As a result Switch 29 Controls and Machine Feedback messages are transmitted at less frequently than the Hydraulic Controls To protect against c
38. n a communication failure the system shuts down into failsafe mode OPUS is currently in use on loaders in steel mills and carrying land mine detection equipment 7 b Figure 2 5 Robotec teleoperated systems a Vehicle Network for Unmanned Systems VeNUS b Robotech Industries HazHandler 7 2 3 Control Methods Control methods for teleoperated systems can be divided into three generic categories direct coordinated and supervisory control Direct control is the traditional control systems based on hand controllers and video feedback Coordinated control builds upon direct control by incorporating a control loop in the teleoperated vehicle Supervisory control includes a system in which an operator oversees a lower level of intelligence by monitoring and reprogramming system routines Direct Control The most common method for teleoperation control is through direct control Traditionally hand controllers are used to control the system while monitoring video feedback from cameras mounted on the teleoperated system In direct control the remote operator is controlling the system in the same way as an on board operator would Direct control techniques are appropriate when real time human decision making and control is required and when the environment can support high bandwidth low delay communications 8 By nature direct control methods have a level of control delay This delay may be negligible or significant dependi
39. nd Ka V Input deadband ef 100 for Vero gt V joystick 20 6 6 P dioi an If the joystick or pedal voltage exceeds the maximum voltage Vmax or minimum voltage Vmin the input voltage is set at that maximum or minimum value The developed C software was incorporated into the following LabVIEW block diagram through a FORMULA NODE as shown in figure 6 2 gt Jeeetkch Input Votiage Parone ei Aleck Dieren suis siii is Aere nift kesir ra Tibalt ER UV cece hey 100 Carni eA DB M e Candi Canty Pad DD us krralik 0 77 iinput input Fiat Ainge Input Fir WHinputsspg v i Figure 6 2 Joystick and pedal control voltage scaling with dead band in LabVIEW Once the control voltages have been properly scaled the Hydraulic Control message can be compiled The ASCII character h 68h will represent the Hydraulic Controls message identifier The bucket arm boom swing left track and right track controls will respectively follow the identifier in the message as shown in table 6 4 Each 36 of these six controls will be represented by a scaled integer value of 100 to 100 indicating the rate of closing or opening of each hydraulic actuator Table 6 4 Hydraulic Control Message Field Name Type Units Description 1 Control ID Byte N A ASCII character h 68 designated for control of hydraulic actuators 2 Bucket Byte Scaled Integer Lower Limit 100 Upper Limit 100 3
40. ndalone device with independent processor and memory After deployment the host PC system monitors the executed software on the RT Series hardware as shown in figure 4 3 Host PC Networked RT Series Hardware Ethernet Communication Channel LabVIEW or RT Development System Figure 4 3 Real time LabVIEW deployment hardware RT Engine If the host PC crashes the user interface between the host PC and the embedded LabVIEW Real Time application ceases The executed software on the RT Engine remains unaffected by the communication loss 4 3 Web Server The LabVIEW Web Server facilitates the creation of Web pages modeled after developed VI front panels Users connected to the Web Server can monitor and control an executed 25 VI through an Ethernet connection and a standard Web browser With Internet connectivity users anywhere in the world can access and control a LabVIEW program Access levels such as read only to prohibit access to unauthorized users or full control are available in the Web Server In figure 4 4 the Function Waveform Generation vi front panel is shown in Microsoft Explorer 6 0 Web browser J p si Wavefant Generation M kteaplt biter aplaris Da Lk Fa r rer oci pe E al 2 4 Lo Seef TP Femij Wi E ill hinge i Tan P anc bin search tog ii Ak Jeet Aleta s Function Waveform Generation OF LB Tee inact anna gc onesie oe rg Bar rhainpu ro tha demad valumm
41. ng upon the flight time of the radio transmission and computer processing Significant delays are typical in direct control of space vehicles Coming from the Earth surface direct control of vehicles in low Earth orbit results in a round trip delay the time from sending a signal until the receipt of feedback pertaining to the signal of 0 4 seconds For vehicles on or near the moon these delays are typically 3 seconds Early experiments with time delay in direct control applications used a move and wait strategy In this strategy the operator commands a small incremental motion waits for the feedback and then commands another small motion With such small control movements the time to complete task can be long As a result continuous direct control of space vehicle systems has been discouraged 9 Predictor displays present a computer derived estimate of the teleoperated vehicle future state This estimate can then be displayed to the operator for decision making Predictor displays are useful in applications with significant transmission delays and slow on board camera frame rates Predicator displays have been successfully demonstrated on gun sights ships and submarines and as head up optical landing aids for aircraft pilots 10 Coordinated Control Coordinated control expands on direct control by adding a level of internal control at the teleoperated vehicle As with direct control the operator transmits a control signal to the teleop
42. of up to nine FieldPoint I O input output modules FieldPoint controllers connect directly to Ethernet and auto negotiate on the network for 10 Mb s or 100 Mb s communication rates The Ethernet port serves as a high speed link for downloading application code performing real time software debugging and exchanging information with other networked computers Such connectivity is built on a TCP IP network protocol and incorporates publisher subscriber networking The FP 2000 controller also contains a RS 232 port for serial communication 13 Figure 3 2 National Instruments FieldPoint FP 2000 controller 13 A variety of I O modules can be connected to the FieldPoint controllers including analog discrete counter and dual channel modules These modules slide into terminal bases and can be linked from a FieldPoint controller module as shown in figure 3 3 The controller module can then execute the functions of each I O module through developed LabVIEW software In this project analog input FP AI 100 analog output FP AO 210 digital input FP DI 300 and relay FP RLY 420 modules are used 11 Figure 3 3 FieldPoint distributed I O system 13 During testing it was noticed that these modules occasionally failed to connect properly This failure was caused by poor terminal block connector design The latest National Instruments compact FieldPoint cFP product line has resolved this issue by using a 4 port or 8 port backplane
43. ommunication failures the communication protocol incorporates a failsafe system If the teleoperated machine receives sequential corrupted messages or does not receive a message over a set time period the machine software triggers a Failsafe Mode In the Failsafe Mode all hydraulic actuation returns to a motionless level All devices within the Switch Controls remain at a current state After Failsafe Mode activation the software falls into Synchronization Mode and attempts to re establish communications with the remote station see section 7 2 5 3 Telegram Format The following telegram format is used in all communicated data between the remote station and the teleoperated machine This standardization provides a foundation for current and future exchanges of messages The developed telegram format for this project can be divided into four sections 1 Start Character 2 Message Length 3 Message 4 CRC Table 5 1 Telegram format Field Name Data Type Description 1 Start Character Byte Represented by 23h 2 Message Length Byte 1 255 0 not used Represents the message length 3 Message Array of bytes 1 255 bytes 4 CRC Word 16 bit cycle redundancy check based on message length and message data First the Start Character of all telegrams is represented by the American Standard Code for Information Exchange ASCII character This character was chosen as the Start Chara
44. on 6 8 37 open E ES H control v close min close y max_ close for 0 gt I nol gt 100 6 8 where V max close 1S the maximum voltage of the hydraulic close proportional valve Vin close 18 the minimum voltage of the hydraulic close proportional valve Based upon equations 6 7 and 6 8 the developed LabVIEW software converts the Hcontrot Value to reference voltages of the open and close proportional valves as shown in figure 6 3 The Hydraulic Controls message is converted to an array of unsigned 8 bit numbers representing the movement rate of each hydraulic actuator This array of percentages is then sent into a while loop for conversion to the open and the close proportional valve voltages for each hydraulic control 7 Dei Yot Har howe ie HBncbsed LC Pet e Se rel P mil t Lasel Figure 6 3 Proportional valve reference voltage calculations in LabVIEW After the proportional valve reference voltages are calculated the FP Write vi is used to output the corresponding voltages through the FP AO 210 analog output module 38 6 3 Switch Control Message In addition to the hydraulic controls customer specifications called for teleoperated control of the CX 160 engine ignition remote camera power and remote front camera pan tilt zoom and focus Each of these switch controls can be at an ON or OFF state A 5 V output represents an ON state and a 0 V output represents an OFF state Each switch
45. ormata en Ge e Ee Ee 30 Chapter 6 Message Compilation sess 32 6 1 Synchronization Messages Ada enee Ree dE RARE ERI SO EE 32 6 2 Hydraulic Control Message i ciaeeee erben erbe rar Rep sou eer nn rnnneee 34 6 3 witch Control Message outre cnc eta lone ra eue EE UR DE ERN BUE pd rade 39 6 4 Machine Feedback M6Ss8d96 sioe EE EHE EUER EHE SMS RES Ya Tbe Pa a 40 5 5 Update Settings Message is ss NER REA ERA TAE ED e 41 Chapter 7 Conclusion EE 44 Referents yrrir era aE r REE OA GR ORT I ERR XU ed SS 46 i2 DENN 48 This page left intentionally blank vi List of Tables 5 1 6 1 6 2 6 3 6 4 6 5 6 6 6 7 Telegram een E EE 30 Remote Station Synchronization Message 33 Machine Synchronization Message onset aset kn terere Cpu aret d ea etaed 33 Machine Synchronization Confirmation Message 33 Hydraulic Control Message i 41 eene en e ern ee eee pea EO Enn Ren nein iae 37 Switchi Control Messages EE 40 Machine Feedback Messages cx D GREAT NE ERA E OSEE XAR EV EUER 41 Machine EE 43 vii List of Figures 1 1 2 1 2 2 23 2 4 2 5 3 1 3 2 3 3 3 4 3 5 3 6 3 7 3 8 3 9 3 10 3 11 3 12 3 13 4 1 4 2 4 3 4 4 5 1 5 2 5 3 6 1 6 2 6 3 7 1 Case EEN 2 Vehicleteltoperation EE 4 Teleoperated dune E DEE 5 ORILLC Standard Teleoperation System GIS 6 Omnitech teleoperated systems ol 7 Robotec teleoperated systems 7 ege eee rere e ho
46. rdware is shown below in figure 3 11 Link to remote Discrete station Packaged Voltages Data Ignition A EH f Camera functions RLY 420 SRM 6000 FP 2000 Serial Data Engine Controller Unit ECU FP 2000 Figure 3 11 Teleoperated machine hardware flow diagram The teleoperated system electronic components are housed in a water tight enclosure Fans and ventilation are added to the electronic housing to ensure that the electronic equipment is adequately cooled Automotive fuses and electronic filtering are implemented in order to protect the electronic equipment from power supply irregularities Implementing an array of cameras on the teleoperated machine provides video feedback to the operator Stationary wide angle lens cameras are placed on the front and rear of the excavator This placement gives the operator a wide view of the environment in front of and behind of the excavator An additional camera with pan tilt zoom and focus capability is placed on the front of the excavator see figure 3 12 These camera 19 features are controlled by the operator at the remote station Such camera versatility allows the operator to orientate and zoom the camera to areas of interest The front stationary camera also relays audio to the operator These three cameras transmit through wireless 2 4 GHz discrete frequency transmitters Figure 3 12 Remote cameras on teleoperated CX 160 a stationary and pan tilt zoom front camera
47. roportional valve voltage for 1 bucket close operation 5 Maximum Voltage Bucket Closed Single Volts Proportional valve voltage for 100 bucket close operation 6 Minimum Voltage Arm Up Single Volts Proportional valve voltage for 1 arm up operation 7 Maximum Voltage Arm Up Single Volts Proportional valve voltage for 100 arm up operation 8 Minimum Voltage Arm Down Single Volts Proportional valve voltage for 1 arm down operation 9 Maximum Voltage Arm Down Single Volts Proportional valve voltage for 100 arm down operation 10 Minimum Voltage Boom Up Single Volts Proportional valve voltage for 1 boom up operation 11 Maximum Voltage Boom Up Single Volts Proportional valve voltage for 100 boom up operation 12 Minimum Voltage Boom Down Single Volts Proportional valve voltage for 1 boom down operation 13 Maximum Voltage Boom Down Single Volts Proportional valve voltage for 100 boom down operation 14 Minimum Voltage Swing Left Single Volts Proportional valve voltage for 1 swing left operation 15 Maximum Voltage Swing Left Single Volts Proportional valve voltage for 100 swing left operation 16 Minimum Voltage Swing Right Single Volts Proportional valve voltage for 1 swing right operation 17 Maximum Voltage Swing Right Single Volts Proportional valve voltage for 100 swing right operation 18 Minimum Voltage Left Track Forward Single Volts Proportional valve voltage for 1 left track forward operation 19 Maximum Voltage Left Track Forward Single
48. rrere 8 Teleoperated EE EE 10 National Instruments FieldPoint FP 2000 controller 13 11 FieldPoint distributed I O system 31 12 Data Linc SRM 6000 wireless serial modem TA 13 Futaba Industrial Radio Control VSD 2007IIa ccc e eee e ence eens 13 Remote SEAL OM erg deet epas TUE EA GA NOS ui RERO AT KR RES UAE 14 Remote station hardware flow dagram nerne rene 15 Operator CONGO Cia he Dtm read tede nl dc Senate eee MALE ETE Med E A 16 Operator graphical user TRterfaces Se SERA EE EE EE 17 Case CX 160 degrees of freedom vtec o OQ MO E CHER eas 18 Teleoperated machine hardware flow dagram 19 Remote cameras on teleoperated CX 1Iot cece cece eee eee eee ee ene e ene es 20 Teleoperated machine software mterf ce eese 21 Front panel of Function Waveform Generation wt 23 Block diagram of Function Waveform Generation vi 24 Real time LabVIEW deployment bardware eee eneeeees 25 The Function Waveform Generation vi Web server interface 26 Required control and feedback data for teleoperated control 00seeneeee 28 Communication protocol for teleoperated CX 160 ccc cece 29 Block didsram EE 31 Synchronization flow diagram ccccescssccsenescsecesecebeceaesasecssacseneees 34 Joystick and pedal control voltage scaling with dead band in LabVIEW 36 Proportional valve reference voltage calculation in LabVIEW 38 Teleoperated CX 160 excavator in operaton enn e
49. t Used 15 Not Used 16 Not Used 17 Not Used When the teleoperated machine receives the transmitted Switch Controls message the 16 bit number representing the switch status is routed to the FP Write vi This VI then opens or closes each relay port on the FP RLY 420 6 4 Machine Feedback Message The software on the CX 160 engine control unit ECU was modified by Sumitomo to output a serial string via an unused ECU RS 232 port The ECU feedback string transmits the CX 160 fuel level oil temperature water temperature warning messages error messages and the excavator emergency stop status at 500 ms intervals A second FieldPoint controller connected to the ECU reads the serial strings and stores the most current ECU feedback on a published data socket The main FieldPoint controller reads 40 the published data through an Ethernet connection and VSD 2002 emergency stop status through a digital input At an inactive state the emergency stop input has a value of 5 volts At an active state the emergency stop input has a value of 0 volts Once the ECU feedback and emergency stop status have been acquired the Machine Feedback message can be compiled The ASCII character m 6Dh will represent the Machine Feedback message identifier The ECU and emergency stop values will respectively follow the identifier in the message as shown in table 6 6 Table 6 6 Machine Feedback Message
50. ts of the final CRC Some of the popular CRC polynomials are CRC 12 CRC 16 and CRC 32 in which each number corresponds to the number of bits in the CRC message As the number of CRC bits increases the validation error decreases With an error rate of 99 9985 CRC 16 is used to validate message integrity as shown in the block diagram in figure 5 3 19 fr CR vi Black Diagram Fie Ge Grerate De Browse Mm teb Figure 5 3 Block diagram of CRC VI 31 Chapter 6 Message Compilation In order to reduce software development time for both deployment and future expansion a framework for Messages was developed Such standardization reduces the development time for the integration and or modification of hardware operator controls and feedback and failsafe systems Moreover this standardization may be implemented on additional teleoperated equipment with minimal software changes This section presents the message architecture for real time control of a teleoperated CX 160 excavator The current list of messages includes Synchronization Hydraulic Controls Switch Controls Machine Feedback and Update Settings 6 1 Synchronization Messages To coordinate master slave control a synchronization program was developed to establish communication between the remote station and the teleoperated machine The synchronization program is executed upon system start up and communication failures The synchronization program works like the UNIX and D
51. vides an effective development method for large and complex programs Since its founding in 1986 LabVIEW has been implemented in a variety of environments including space shuttles NAVY submarines R amp D laboratories and universities worldwide 17 Consequently LabVIEW development sites have been established to facilitate its rapid growth and widespread use The National Instrument s Developer Zone http www zone ni com nd the LabVIEW Technical Resource Publication hitp www Itrpub com are leading LabVIEW resources for software development guidelines and programming examples 24 4 2 Real Time Engine All developed software applications in this project are run under LabVIEW Real Time RT Engine RT Engine provides deterministic real time performance which non real time operating systems such as Windows cannot ensure The features that enable the RT Engine to provide deterministic real time performance are 1 the scheduler and other operating system services adhere to real time operation 2 RT Engine is tuned for real time performance 3 RT Series hardware uses no virtual memory thereby removing a major source of unpredictability in deterministic systems 18 All LabVIEW software development is done on a host PC system Once software is ready for deployment the host PC compiles the LabVIEW software and uploads the compiled program to RT Series hardware through an Ethernet connection The RT series hardware is a sta
52. voltage is read by software and converted into binary numbers in which ON values correspond to a bit value of 1 while OFF values correspond to a bit value of 0 By sampling all 16 ports on the FP DI 210 a 16 bit number is compiled wherein each bit represents the status of the corresponding port Once these switch controls values have been acquired the Switch Controls message can be compiled The ASCII character s 73h will represent the Switch Controls message identifier The switch control value of the engine standby engine start camera power and camera rotation will respectively follow the identifier in the message as shown in table 6 5 39 Table 6 5 Switch Controls Message Field Name Type Units Description 1 Control ID Byte N A Character s 73h designated for control of switched controls 2 Engine Standby Bit N A 0 Engine off 1 Engine ACC On 3 Engine Start Bit N A 0 None 1 Start Engine 4 Camera Power Bit N A 0 Cameras Off 1 Cameras On 5 Camera Pan Left Bit N A 0 None 1 Pan Left 6 Camera Pan Right Bit N A 0 None 1 Pan Right 7 Camera Tilt Up Bit N A 0 None 1 Tile Up 8 Camera Tilt Down Bit N A 0 None 1 Tilt Down 9 Camera Zoom In Bit N A 0 None 1 Zoom In 10 Camera Zoom Out Bit N A 0 None 1 Zoom Out 11 Camera Focus In Bit N A 0 None Focus In 12 Camera Focus Out Bit N A 0 None 1 Focus Out 13 Not Used 14 No

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