Autonomous Underwater Vehicle Programming
Contents
1. 12 VDC and 28 VDC which is provided by the AUV s onboard DC Batteries This DVL also comes with its own utility program BBTalk This software is used to help set up use test and trouble shoot the ExplorerDVL However this Software also requires a Windows XP operating system see 5 for additional windows compatible O S In order to test the DVL the reader is again referred to page 15 of 5 In order to properly mount this device the operation manual recommends mounting the transducer head with Beam 3 instrument y axis rotated 45 degrees relative to the ship forward axis It is also important to protect the transducer from damage as this will result in a diminished performance or inoperability of the ExplorerDVL The pin out for the J3 plug of the DVL is shown Table 3 2i HMR3000 Honeywell Magnetic Compass The HMR3000 Honeywell Magnetic compass provides pitch roll and heading outputs for navigation 13 and needs to be strapped to the DVL It was obtained this summer when a group member determined that it was needed so that the DVL mentioned above could work properly For further information about this compass the reader is referred to the HMR3000 information sheet 13 2j uEye USB 2 0 Cameras For vision this AUV incorporates two uEye USB 2 0 cameras These cameras come with a rugged housing making them great for industrial or robotic use For the AUV one camera is mounted facing forward while the other is2. Instrument VI was developed to allow users to remote control the AUV through a TeamViewer remote login application Work on the DVL positioning system has also moved forward but more work is still required as is the case for the Vision Acoustic and Depth Sensor systems 6 Acknowledgements Several people were instrumental to the progress made in this project throughout the summer I would like to thank Dr Michael R Gustafson for agreeing to sponsor my project Dr Robert E Kielb for his support and funding approval and Poornima Gadamsetty for her diligent efforts continuous presence and discoveries throughout the summer 7 References 1 ROS an open source Robot Operating System Morgan Quigley Brian Gerkey Ken Conley Josh Faust Tully Foote Jeremy Leibs Eric Berger Rob Wheeler Andrew Y Ng To Appear in Open source software workshop of the International Conference on Robotics and Automation ICRA 2009 2 Bishop Robert 2007 LabVIEW 8 Student Edition National Instruments Pearson Prentice Hall Saddle River NJ 3 Brokav Paul An IC Amplifier User s Guide to Decoupling Grounding and Making Things Go Right for a Change Analog Devices AN 202 Application Note Norwood MA Online http www analog com static imported files application_notes 135208865AN 202 pdf 4 Tecnadyne 2006 General Power System Guidelines Online http www tecnadyne com support htm 5 ExplorerDVL Operation Manual Online htt
3. This required the dismantling of the old chassis and the re pinning and wiring of new connections However as stated above this work was completed in a couple of weeks Once wiring was complete the power system was connected to the PC 104 board and DAC card to confirm the electrical system was operable The PC 104 SBC was then booted and software described below was run to confirm that the system and software was capable of running the thrusters 3b Driver Interface Software In order to utilize the LabVIEW software and have it interface the PCM MIO DAC card drivers a Dynamic Link Library DLL was created using Visual C This particular part of the project is perhaps the most innovative as the author was unable to find any software that could perform this function After contacting the manufacturer WinSystems and learning that they had no LabVIEW driver software for the AUV team to use the author began researching possible options for interfacing the DAC card drivers Further study revealed that LabVIEW has the ability to call DLL files written in C or C from it Call Library Function 11 Thus after reading the operations manual 14 15 for the DAC card and listing applicable functions the author created a DLL to call these device drivers functions from LabVIEW anytime a voltage output is required Once the DLL was completed a virtual instrument VI was created LV_DAC_Interface vi to handle the DLL and control the passing of channel
4. boards expense and the team s inexperience with single board computers a choice was made to eliminate all other possibilities before ordering a new board As a result the board remained an ongoing frustration for nearly five weeks as troubleshooting continually failed to locate the fault on the board and smaller components were replaced those being a new Compact Flash Card a system RAM chip and a battery Note that for lab use the PC 104 is powered by an ATX power source with its green and black wires shorted together The ATX power source is standard in many personal computers Figure 1 shows the PC 104 connected to a hard drive and DVD player recorder Figure 1 Epic Nano 4386A R10 PC 104 Single Board Computer SBC Eventually the CPU was transferred to a new board and this eliminated the rebooting faults however upon installing Windows XP a page fault developed Because of this and the development of IDE problems another week was spent unsuccessfully attempting to install LabVIEW At one point the PC 104 Board was even turned over to Duke IT to see if they could install the LabVIEW software After a week Duke OIT also gave up on this endeavor The fix ended up being a complete reinstallation of the Windows XP operating system after connecting a DVD and external Hard Drive and reconfiguring the SBC s BIOS This attempt resulted in a fully functional O S and LabVIEW was then installed Unfortunately the 8 GB Compact Flash
5. did not possess enough memory to support the 6 GB of space required by LabVIEW and the other 1 7 GB required by Windows XP to operate Initially the AUV team thought the CF cards could only be type II which is a much more expensive CF card around 229 00 with a maximum storage capacity of 16 GB Fortunately an AUV team member discovered that type I cards were interchangeable in Type II CF sockets and that the PC 104 board would support a Type I CF card as well As a result the 32 GB CF card for the project was purchased With the new card the O S and required software was finally installed Ultimately the most needed requirement for this phase of the project was a lot of patience and a better understanding of the system BIOS configurations along with the complete replacement of the PC 104 board minus the CPU 2b PCM MIO Digital to Analog DAC Card The PCM MIO board used for this project has 8 digital to analog outputs and 16 analog to digital inputs It also provides a sample rate of 85 ksps Amusingly enough this is the one piece of equipment that the AUV team was told was inoperable that actually worked After reading the operation manual for this piece of equipment the author determined that the address jumpers on the DAC card were misconfigured However once these jumpers were setup properly the PCM MIO was recognized by the PC 104 SBC The only real problem with this DAC card is that WinSystems doesn t provide LabVIEW driver
6. 8 36 VDC The FDC60 24D12 DC DC Converter provides the AUV circuitry saava with a steady supply of 12 VDC power This converter was M e mounted on a circuit card by previous AUV teams Unfortunately the PCB express schematics detailing the mounting board layout was not available This forced the author to test each of the outputs of the power board shown to the right in Figure 4 in order to verify the output values when 30 VDC is applied Having determined that Figure 4 FDC60 24D12 DC DC Converter all outputs of these boards is 12 VDC the author included two DC DC converters in the new AUV wiring One converter provides a steady 12 VDC to the PC 104 SBC and the other DC DC converter provides and intermittent 12 VDC to the control logic of the motors as determined by the AUV s control system 2e The ISO 4 Card The ISO 4 card is manufactured by Tecnadyne this is the same manufacturer of the thrusters used for this AUV and provides isolated 5 VDC control signals and 12 VDC instrument power for up to four Tecnadyne motors The AUV utilizes two ISO 4 cards to provide instrument power instrument ground and a control signals to each of the AUV s six motors These cards are in turn connected to a 12 VDC power source provided by the AUV s DC DC converter and six analog control signals provided by the PCM MIO DAC Card The ISO 4 cards are implemented as a precautionary measure According to the documentatio
7. Autonomous Underwater Vehicle Programming and System Interfacing Semester Summer 2009 Proposed Dates 13 May 7 August Credit Hours 3 Name Jacob H Cox Jr Student ID 1743498 Sponsoring faculty Dr Michael Gustafson Name of supervisor Dr Nan Jokerst Phone 706 951 9741 Email jacob cox duke edu Autonomous Underwater Vehicle Programming and System Interfacing Jacob Cox jacob cox duke edu Pratt School of Engineering Duke University Summer 2009 13 May 7 August Abstract the Duke Robotics club hopes to compete in the annual International Autonomous Underwater Vehicle AUV competition next year To this end a project was undertaken by the author to develop the software interfaces required by the AUV to control its thrusters and steer the AUV in a remote control setting This work provides a dynamic link library DLL file that successfully interfaces LabVIEW a graphical programming language with the C code based hardware drivers of the PCM MIO Digital to Analog card DAC Furthermore the author provides a detailed overview of the components comprising the AUV along with a newly revised wiring schematic showing how the AUVs electrical components are now interfaced 1 Introduction In July 2007 the Duke University Robotics Club competed in the 10 annual International Autonomous Underwater Vehicle competition held in San Diego California 9 With their robot named Scylla the robotics team had high expectation
8. Yoltage Motor 0 Motor 4 ry Motor Rum Time Process Shop z E E 3 Motor 1 Motor 5 Pitch System Stop 2 jz G idle ALE Analog 0 14 a fio Pitch Time EE Figure 12 Steering Controls Virtual Instrument Of the options provided AUV Steering offers seven possible states Those are Idle TurnRight TurnLeft GoForward Reverse Dive Rise and Test respectively As their name implies each state controls the voltages on different channels of the DAC card to achieve a specific action Motor Voltage sets the voltage value to be applied on each channel during a given mode with exceptions being for Idle or Test modes Motor Run Time sets the duration for which the voltage will be applied to the channels Pitch still needs to be adjusted by testing but it applies a voltage to control Motor 2 A positive voltage pulls the nose of the AUV down while a negative voltage pulls the nose up The Depth On button and Depth Voltage allows the user to set the voltage on motors O 2 and 4 in order to control the AUV s depth while it makes other movements Also this program incorporates a safety function preventing voltages from being applied to the DAC Channels unless the Analog Out button is set to True In order to stop the entire program the user may simply press System Stop however if a process such as GoForward needs to be interrupted the user can press the Process Stop button This virtual instrument VI also provides ind
9. als to be amplified to a range suitable for acoustic detection the filtering and triangulation software can be developed Perhaps ee the most difficult work ahead for the AUV team is Power the positioning system which uses the Doppler Velocity Logger DVL Due to the expense at Figure 14 AUV System Objectives which this device was obtained 15 000 00 and the fact that the new chassis was designed specifically for the new DVL the AUV team felt compelled to use it However while it is smaller and lighter than its predecessor simple testing requires at least a 0 5 meter depth pool be available Additionally the DVL requires that a digital compass be strapped to it so that the two can work together to determine the AUV s movement and position in an X Y Z coordinate plane As of this paper s first draft a compass has been purchased and a small pool is on order so DVL software system development can begin soon 5 Conclusion While an average of two people worked on the AUV project throughout the summer at any given time a substantial amount of work was completed and the author believes that the AUV is well on its way to competing in next summer s International Autonomous Underwater Vehicle competition The electrical system is ready the PC 104 SBC and PCM MIO DAC card are functioning properly and software is now developed that allows LabVIEW to communicate with the DAC card hardware drivers Additionally a LabVIEW Virtual
10. as chosen due to its compatibility with the LabVIEW software package and the AUV team s familiarity with the O S For the most part software was chosen based on its ease of use price and familiarity Several factors contributed to the team s choice of LabVIEW For instance it is used by industry worldwide for robotics applications and is praised as a powerful and flexible design tool 2 Additionally Duke University owns a full license for the software so its use added no additional cost to the development of the AUV s control system With LabVIEW being a graphical programming language the team believes that this software provides a more intuitive way of understanding the code produced by other programmers LabVIEW even provides a trace option that allows users to follow the flow of the code to see how the program performs its functions which provides a visual means for program debugging Thus the author believes that the use of LabVIEW will make it easier for work developed in LabVIEW to be understood by future AUV project teams Therefore LabVIEW is seen by the team as a worthwhile endeavor for the AUV project and software familiarization Still despite the rising popularity of LabVIEW and its use in industry one setback initially encountered by the AUV team involved a lack of support by hardware vendors to provide LabVIEW drivers for their hardware In the case of this project the WinSystems PCM MIO DAC card was chosen due to its eigh
11. e a little innovation by developing a LabVIEW and hardware driver interface allowing LabVIEW to call C functions from the driver libraries provided with the DAC card 3a AUV Schematics and Wiring Before the wiring for the AUV could be completed the author first had to ascertain how all components were originally interfaced before developing a new plan for using most of the old components A schematic for the new wiring plan developed by the author is shown below In this schematic colors represent various voltages For instance White Grey represents 30 VDC Green represents 12 VDC and Orange represents either 5 VDC or a control voltage ranging from 5 VDC to 5 VDC Analog Additionally the Black and Red wires represent ground for the two isolated circuits shown in the diagram The diagram in Figure 11 further shows how the AUVs components are interfaced with one another In Figure 11 the first components of interest are the relays They provide on off switching for the circuit power sources For example one power source two batteries providing approximately 30 VDC to each of the six motors whenever 5 VDC is applied to the input terminal of relay 3 which is connected in series with the motors and batteries A second power source provides a step down voltage via DC DC converter of 12 VDC to the PC 104 SBC so long as 7 VDC is applied to the input terminal of relay 1 Relay 1 is connected in series with the DC DC converter and batte
12. hes millimeters aasia Wenn Seen Screw Torque Requirements 6 32 Screws 10 in Ibs 8 32 and seiscranen abner 2 10 32 Screws 20in Ibs Screws dry without grease amenna aan 1 0 1 0 1 0 1 0 Figure 3 Crydom Relay The current system as it now stands requires three D2D12 relays to create a break between power sources and their intended destinations Whenever a voltage of 3 5 VDC or greater is applied to its input the relay allows the Output nodes to pass current Note that it 1s imperative that the output terminals be connected appropriately as the relay will not work correctly if the positive and negative terminals are not connected to each other respectively If connected backwards the relay will allow current to flow through the output terminals regardless of the input voltage Yes this comes from experience For the AUV one relay controls the power provided to the PC 104 SBC This power is continuous so long as the AUV power switch is closed The second relay allows the Digital to Analog DAC card to control instrument power provided to motors and control logic This is discussed further in the implementation section of this paper when the wiring schematic is discussed Finally a third relay controls the power provided to the motors This is also discussed with the wiring schematics in the implementation section 2d FDC60 24D12 DC DC Converter Model Number ut Output Am Input Range iy iit M iT FDC60 24D12 1
13. icators that show the AUV s current state of movement Additional information about which motors and what power levels are applied are also visible Motor O Motor 2 and Motor 4 indicators show what voltages are applied to the Z up down coordinate motors while Motor 1 Motor 3 and Motor 5 provide values assigned to motors in the X Y North South coordinate plane Furthermore just as the motors are located in tandem at specific points of the AUV the indicators are oriented in a similar manner on the control board for visual comparison Finally the values associated with Analog_O and Analog_1 indicate that 4 volts is being applied to the appropriate relay to allow thrusters to receive power for their motors and instrument logic Figure 13 on the next page shows the top most view of the Steering Controls vi Included in this virtual instrument are the Thrust Pwr Cntrl the LV_DAC_ Interface the Analog Output and the Pwr Ramp Volt virtual instruments VI Each of these VIs were developed by the author and are used to provide voltage ramping the motor requires that voltage control be ramped at a rate of one volt per 10 milliseconds along with voltage output control on the DAC card Also in Figure 13 each of the orange rectangular boxes represents a Float type global variable while the green rectangular boxes represent Boolean type global variables Generally it is discouraged to use such variables in programming due to race conditions possib
14. ly altering global variables before a current sequence is completed and the difficulty it creates in regard to debugging In LabVIEW however local or global variables are required to pass values inside loop structure such as for and while loops to other threads running in parallel with the loop structure Still in order to prevent race conditions from occurring a millisecond multiple function is used to manage timing within loop structures so that all processes are given enough time to run to completion Motor Ru Tine zanm Tre T si Pitch Time c c M i a Analog a Thruster Stop 9 mm sann 2 e Analog 1 Depth votage Sanaa Thruster Stop od i Da System Shige TE si EH 4 Results and Discussion While this project presented some initial challenges substantial progress was made to rewire the AUV distribute power appropriately repair its single board computer and DAC card and install the required software Once these hurdles were overcome progress moved forward much more quickly The DAC card was interfaced with LabVIEW via a DLL file written in Virtual C and virtual instruments were implemented to provide motor control With this phase of the project complete much work still needs to be completed with the AUV The greatest priority at this time has to be setting up the chassis to allow us to install the electrical components and start testi
15. mounted facing the bottom of the AUV Together these cameras are used to track objects either on the bottom of a pool or ahead of the vehicle Another aspect of these l cameras making them convenient for AUV use is their uffe LabVIEW drivers Sample programs are also provided to Getting stared assist with the development of more specialized applications For more information about these cameras the Figure 9 uEye USB 2 0 Camera 6 reader is referred to the product s user manual 6 2k TC4013 Miniature Reference Hydrophone In order to triangulate an acoustic beacon the AUV has three miniature TC4013 hydrophones These omnidirectional hydrophones boast a high sensitivity to frequencies ranging from 1 kHz to 170 kHz 12 Additionally they do not require that any power be applied to them directly However they do require signal amplification in order for the signals they detect to be read by the AUV s DAC card Currently no amplification hardware has been developed In past years not Figure 10 TC4013 Miniature Reference Hydrophone only was an op amp used but a band pass filter and hardware requiring its own drivers was developed LabVIEW the software used for this project has special program features that make implementing a bypass filter in software much more feasible for this AUV 21 Software The software used for this AUV includes Windows XP home edition LabVIEW Microsoft Visual C 7 and TeamViewer Windows XP w
16. n provided by Tecnadyne 4 feedback from motors is capable of damaging the control system s DAC Card if not protected The ISO 4 cards provide the desired protection from these feedback signals by creating isolated circuits for each motor 2f Model 250 DC Brushless Thrusters Figure 5 The ISO 4 Card The AUV utilizes six motors for steering and propulsion Note that the robotics club only owns five thrusters and that one has been borrowed in competitions past Each motor has five inputs pins 1 5 and one output pin 6 Pin attaches to a black wire and provides the ground for the thruster s power source Pin 2 attaches to a white wire and provides up to a 150 VDC 1 9A power input In the case of this AUV the power is provided from two Power RC Pro Lite MS 4s4pl 8000mAH LiPo Batteries 10 that provide approximately 30 VDC 1 VDC Pin 3 attaches to a red wire and provides the instrument power ground Pin 4 attaches to a green wire and provides the thruster with its 12 VDC Instrument power Pin 5 is attached to an orange wire and provides the thruster with its 5 VDC control voltage It is important to note that this voltage should always rise and fall with some unit of time and never step 12 0in fe Taom MP i i 6 or C cti a Pin aera Pin Assignment Color 21 7 in a 4 3cm 1 Black Motor Power Ground 2 White 24 VDC Motor Power 3 Red Instrument Power Ground 4 Green 12 VDC Instr
17. ng the AUV in the water At this point no testing can be done with the chassis due to it still being unfinished Specifically the chassis needs to be sealed and holes need to be drilled to facilitate the connection of the SeaCon connectors needed for thruster controls The second issue of similar importance it to determine why the ISO 4 cards are not working The author contacted the vendors and was provided schematics for trouble shooting the boards however this part of the project must be completed in future weeks Pictures of the connections for the ISO 4 interface were emailed to the engineering department of Tecnadyne An email was received from Tecnadyne shortly their after indicating that the connections were correct Looking at the AUV Systems Objectives chart in Figure 14 it is clear that there are many objectives Sinaia competing for completion before this AUV will be ready for testing Still remote control testing can begin nearly as soon as the work on the AUV chassis is completed The vision acoustic depth sensing and positioning systems all still require much work The vision system development for this AUV is ongoing however at this point all required Electrical Wiring cas Hydrophones components needed to implement a vision software Interfaces Control Acoustics program for the AUV are available The acoustic detection system also remains a work in progress Once hardware components are developed to allow hydrophone sign
18. o Thunder Power RC Pro Lite MS 4s4pl 8000mAH LiPo Batteries 10 connected in series Each battery provides approximately 14 8 V DC and provide a combined voltage of 29 6 VDC per set Each set is connected to an isolated circuit Additional safety measures for these circuits include a fast blow type fuse with a current rating 50 higher than the steady state current allowed for by each of the motors 4 Additionally a 450 uF capacitor is placed in parallel to the positive and negative terminals of the battery set providing direct power to the motors in order to protect against voltage spikes created by sudden voltage changes in the motor windings Figure 7 Thunder Power Pro Lite Battery 10 2h ExplorerDVL Doppler Velocity Logger 12 to 28 VDC Transmit Cable Rand ee gt SPI Sensor Receive Cable gu 35 til a eo view Electronics Housing Explorer Transducer Figure 8 Explorer DVL Table 3 Input Power and Communication Interface The ExplorerDVL in the AUV uses 4 x RS232 Connector J3 Wiring communication protocols to communicate with the _ PC 104 board A combination of other protocols is also ossreing avaiable signa ___ Seri Communication Modules ___ RXIA RXTA RX RX1 possible but future AUV teams are referred to the RXIE RXS ExplorerDVL Operation Manual 5 for further nie aad guidance on those protocols For Power the DVL ROS gt requires a DC supply between
19. p www adcp net explorer html 6 User Manual uEye 2 0 Cameras Verstion 2 2 IDS Imaging Development Systems GmbH May 2006 Online http www ueye com 7 MSDN Visual C Developer Center 2009 Microsoft Corporation Online http msdn microsoft com en us visualc default aspx 8 Official Rules and Mission AUVSI amp ONR s 12th Annual International Autonomous Underwater Vehicle Competition July 2009 Online http www auvsi org competitions O9AU VMission pdf 9 Duke Engineering Underwater Robot Competition Proved a Rollercoaster Ride for Duke Robotics Club July 2007 Online http www pratt duke edu news id 1029 10 Thunder Power RC Pro Lite MS 8000mAh 11 1 V 3 Cell Li Poly 3s4p 8000 Lithium Online http www rctoys com rc toys and parts TP 8000 3S4PL RC PARTS THUNDER POWER PRO LITE LI POLY BATTERY html 11 National Instruments NI Development Zone Online http zone ni com dzhp app main 12 Hydrophone TC4013 Miniature Reference Hydrophone Reson 2005 Online www reson com 13 Digital Compass Solution HMR3000 Honeywell International Inc 2006 Online http www magneticsensors com datasheets hmr3000 pdf 14 Operations Manual PCM MIO G 2008 Online http www winsystems com manuals PCM MIO G pdf 15 WinSystems PCM MIO Windows Device Driver Package Windows XP Drivers and Example Online http www winsystems com software mio_xp zip
20. ry source The 7 VDC is applied to the relay s input terminal for as long as the series connected switch is placed in the ON position Finally relay 2 is connected in series within the parallel circuit providing power to the ISO 4 cards which in turn provides 12 VDC Instrument Power to each of the six motors Like the 30 VDC motor power supply the 12 VDC is only applied to the ISO 4 card when 5 VDC sometime 4 VDC is applied to the input terminal of relay 2 from the DAC card Fast Blows Fast Blow Fuse 2001 Figure 11 AUV Wiring Schematic The DC DC converters in Figure 11 allow us to take the 30 VDC from the batteries and convert it to 12 VDC Two separate converters are used so that the PC 104 SBC board is provided continuous power while the ISO 4 and thruster instrument power receive it only when the control program activates the thrusters Other components that will receive a continuous 12 VDC include the Doppler Velocity Logger DVL and the pressure sensor As of this paper however a new pressure sensor must be acquired as the current one is inoperable The two USB video cameras receive their power from the PC 104 board and the hydrophones require no external power One team member is working to develop an amplifier for these hydrophones so future power requirements have not been specified for the acoustic boards Upon completing this wiring diagram the author rewired the AUV to the specifications shown in Figure 11
21. s and voltage values to the DAC card Another limitation of LabVIEW revolved around its inability to pass float type variables to Call Library Functions CLF Since the AUV receives DAC output values in increments of 0 1 VDC this limitation presented a minor challenge to the author s LabVIEW program To compensate the author chose to multiply all values sent to the CLF by 10 so a value of 4 5 is received as 45 by the DLL called in LabVIEW The DLL file was then modified to multiply all incoming values received by LabVIEW by 0 1 and assign the resulting value to a float type variable The float variable is then provided to the set_dac_volt function located in the DLL which is a function of the driver software provided with the PCM MIO DAC card 3c Motor Controls With the DLL and LabVIEW DAC Interface LV_DAC_Interface VI complete the author s attention then turned to developing the VI needed to control the motors The resulting VI is the Steering Controls VI shown in Figure 12 This VI provides motor control for the AUV Options available to the user include AUV Steering Motor Voltage Motor Run Time Pitch Depth On Depth Voltage and Analog Out options gt Steering Controls vi File Edit Wiew Project Operate Toals irda Help Analog o l pene Sec na AU Movement Motor 2 GoForward ia lt i Moving Forward 4 Ficbor 3 Depth On aan caine i Motor Voltage aiad OOOO fo Depth
22. s for a top three finish as was the case during the previous year s competition with their earlier model robot named Charybdis Initial practice runs also contributed to the team s hopes as they successfully completed enough tasks to lock in 2 and 3 place rankings 9 Unfortunately an unforeseen and undiagnosed communication fault along with a fried acoustics board ultimately prevented the team from competing This was the last time Duke University competed in this competition 9 In order for the AUV to successfully compete in the above mentioned tournament held annually the AUV must meet several requirements These requirements include having the AUV pass through an underwater gate land on a beach and set off a light beacon follow a dashed line mark a target identify a brief case containing an acoustic beacon retrieve the briefcase and move to a specified location for the completion of the event 8 9 Seeing this absence from the competition as a project opportunity this author submitted a project proposal offering to research program and implement the programming code required to interface hardware drivers for the AUV and document the results This project was planned to be conducted alongside other team members working on various other aspects of the robot including acoustics vision and positioning While the Duke University Robotics club greatly wished to compete in the International Autonomous Underwater Vehicle
23. s for its hardware This requires that a Dynamic Link List DLL be written in Visual C to call functions written for the C code driver software provided with the PCM MIO board This DLL is in turn called by LabVIEW using its Call Library Function CLF More about this DLL and LabVIEW will be discussed later in the implementation section tr 4 RJ mubinhminm E le pipe IF TELL Le CEs O er 2 oe Ts misinis b oes i i G 4 Ib TF pe AUA ar a ro Jie EELEE ALLI a AAAA AAALLALLLLLLLLLL ZEEE p a F a a i ial at a e p a 2c Crydom Relay Figure 2 PCM M IO Digital to Analog DAC card OUTPUT SPECIFICATIONS MODEL NUMBERS 22007 D2012 D204 D4D07 ea 0 17 4 3 DIA Operating Votage Range Vdc 0 200 Max Load Current Adc 32 TERMINAL mS Min Load Current mA Max Surge Current Adc 10Msec Max On State VoRage Drop Rated Current Vdc Thermal Resistance Junction to Case R c POWI Max On state Resistance Rated Current IR ps ox O ms Max Off State Leakage Current Rated Vokage mA 0 200 0 200 0 400 7 12 40 7 20 20 20 20 22 27 106 17 20 28 2 1 42 15 1 06 0 83 1 06 29 23 05 6 0 1 0 3 03 03 100 00 100 100 Max Turn On Tene psec Max Turn Off Time msec 6 32 TERMINAL 2 PLACES mu 19 8 TA _ INPUT SPECIFICATIONS DC CONTROL 229 Control Voltage Range 3 5 32 Vdc LG mA 5 Vdc 28 mA 32 Vdc All dimensions are in inc
24. t analog outputs sixteen analog inputs and sample rate of 85 ksps however no LabVIEW drivers are provided with this hardware and LabVIEW is unable to utilize this card directly As a result of this limitation Visual C was chosen to develop the Dynamic Link Library DLL files required to use the drivers that came with the PCM MIO DAC card Fortunately Microsoft offers a free download of Microsoft Visual Studio for students and it was chosen for its ability to easily generate DLL files Finally TeamViewer remote login software was chosen in order to access the AUV robot from other computers over the network for testing and as an option for remote control TeamViewer is available from download com and is free for non commercial use 3 Implementation Due to the lack of documentation provided by previous AUV teams this project quickly turned to finding and verifying the operability of all equipment already on hand and documenting how all of these components were met to be interfaced Several other hurdles also quickly presented ranging from mislabeled wire interfaces to an inoperable PC 104 SBC as this project progressed The first obstacle required that the AUV be completely rewired due to mislabeling of connectors and the arrival of a new chassis Since components were being reused from the old chassis all of the required parts had to first be removed before rewiring could occur The new chassis was built by the Duke Medical Instrumen
25. this author s focus quickly turned to developing the schematic for the robot s electronics and circuitry and then interfacing the actual components More about this development will be discussed in the section 3 of this paper While investigating the AUV s component operability and use the author evaluated the following components and documented their use Table 1 Listing of AUV Components Component Listinc NANO 4386A Single Board Computer WinSystems PCM MIO G DAC Card Component Listing No 32 gb Compact Flash Card Type 1 Teledyne ExplorerDVL tecnadyne Model 250 DC Brushless Motors tecnadyne ISO 4 Cards Thunder Power RC Pro Lite MS 4s4pI 8000mAh LiPo uEye 2 0 USB Cameras M R3000 Honeywell magnetic compass H 1 Crydom Solid State Relay Pressure Sensor TBD No 2a Epic Nano 4386A R10 PC 104 Single Board Computer The Epic Nano 4386A R10 PC 104 Single Board Computer SBC used for this project was riddled with problems from the onset of this project It was subject to intermittent faults causing it to reboot at random intervals Additionally the 8 GB Compact Flash card which holds the Windows XP operating system had approximately two gigabytes of corrupted memory requiring a reinstallation of the operating system Trouble shooting this board was also time intensive as the AUV team could not alleviate the constant rebooting Early indications pointed to the PC 104 board itself as the problem however due to the
26. tournament this year the summer team quickly discovered that there were simply too many hurdles to overcome and instead set up preparations to compete in next year s tournament 2 General Overview of Work Conducted In the spirit of innovation the summer robotics team chose to implement its control system in LabVIEW a graphical programming language on a Windows XP platform Several factors contributed to this decision One is that numerous companies are using LabVIEW in commercial markets and the use of this software provided team members with an excellent familiarization of this software Additionally Duke University owns full license to this software so it provided the club with a no cost software option Windows XP was chosen because it supported the LabVIEW software and was readily available in the lab Finally LabVIEW provides numerous tools for working with visual and digital to analog card DAC components Unfortunately initial discoveries revealed that numerous hardware components had been damaged over the previous two years and thus prevented initial software development Such components included the Epic NANO PC 104 single board computer SBC the pressure sensor the acoustic boards the digital to analog converter DAC and the robots internal wiring Additionally little documentation was discovered to allow current project members to further the efforts of the previous year s group As a result of these early setbacks
27. ts shop and from discussions with previous AUV team members and employees at the instrument shop the AUV team was informed that this chassis cost the Duke Robotics club 2 000 00 to have built Still the chassis wasn t delivered until mid way through the summer session and much work is still required before testing the AUV will be possible While SeaCon plugs were removed from the old chassis fairly easily most of the wires had to be cut free Additionally no documentation existed for how the wires were supposed to connect to various components so time had to be spent documenting the hardware to show how each component was met to be interfaced before moving forward Rewiring and pinning the connectors for the motors and hardware components proved time consuming but still progressed to completion over a period of two weeks The next major obstacle that had to be overcome was with the provided single board computer This board was subject to random and frequent shutdowns and it was riddled with errors and faults that hampered all attempts to install an operating system and other software As discussed in section 2a this problem was eventually overcome and the group moved on to installing LabVIEW While this software is a highly abstracted coding language that allows users to visually program by connecting boxes and while statements within a screen this software is not readily applicable to all hardware This is where the author was able to demonstrat
28. ument Power 4 Oin p 2 0iN p 0 5in 10 1cm 5 0cm 1 3cm 5 Orange 5 Analog control a 7 5in gs 19 0cm 6 Brown 5 Analog speed output Figure 6 Model 250 Tecnadyne Thruster 4 Table 2 Model 250 Pin Connections For DC voltage values between 0 5 V and 0 5 V the thrusters will remain still For all voltages in between the thrusters obtain a modified thruster output 4 It is also important to note that control signals must be electrically isolated from the thruster s power source 4 Additionally the control signal must also be held at Ov when thrusters are stopped as opposed to creating an open circuit 4 Another important note is that when controlling the thrusters it is important to use a linear ramp in lieu of a step function for the control signals The recommended control signal ramp is 10 milliseconds volt according to the Tecnadyne Application Note AN601 4 More importantly the control voltage should not be allowed to switch from a positive voltage to a negative voltage without first asserting 0 VDC and allowing the thruster to come to a full stop Pin 6 attaches to a brown wire and provides the 5V analog speed output For the analog control systems the thruster runs forward at full speed for 5 VDC and full reverse at 5 VDC Table 2 shows the pin out 2g Thunder Power RC Pro Lite MS 4s4pl 8000mAH LiPo Batteries The six Tecnadyne DC brushless motors and all circuitry in the AUV are powered by two sets of tw
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