mht ugv operations quick start guide · figure 1 lkill (left) with psi indicator above, and rkill...

MHT UGV Operations Quick Start Guide

J. O’Reilly and C. Milner Amtech Aeronautical Limited Prepared By: Amtech Aeronautical Limited PO Box 1404, Medicine Hat, Alberta T1A 4C1 Contractor's Document Number: TR4487.4002 Contract Project Manager: C. Martin, 403-529-2350 PWGSC Contract Number: W7702-125456/001/EDM CSA: Blake Beckman, 403-544-5502 The scientific or technical validity of this Contract Report is entirely the responsibility of the Contractor and the contents do not necessarily have the approval or endorsement of the Department of National Defence of Canada.

Contract Report DRDC-RDDC-2015-C201 September 2015

© Her Majesty the Queen in Right of Canada, as represented by the Minister of National Defence, 2015

© Sa Majesté la Reine (en droit du Canada), telle que représentée par le ministre de la Défense nationale, 2015

AMTECH AERONAUTICAL LIMITED

© Her Majesty the Queen in Right of Canada (2014) W7702-125456/001/EDM

TR4487.4002Revision IR

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(iii)

TABLE OF CONTENTS

1. BACKGROUND

2. INTRODUCTION

3. GENERAL SAFETY CONSIDERATIONS

3.1 Kill Switch Operation

4. MHT – STANDARD OPERATING PROCEDURE

4.1 Pre-Operation Safety Considerations

4.2 MHT Leader/Follower Demo Configuration

4.4 Starting ROS

4.5 Supply Power

4.6 Upload and Run the Motion Profile

4.7 Remote Control

5. TROUBLESHOOTING

5.1 MHT ROS Controller Module - Playstation Controller

5.2 MHT ROS Vision Module - Firewire Camera

5.3 MHT Communications Module




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1. BACKGROUND

Defence R&D Canada Suffield (DRDC Suffield) conducts research in UGV intelligence for mobility in complex terrain. The research methodology addresses the numerous challenges and uncertainties that complicate the design of UGV systems. Researchers at DRDC Suffield attempt to conduct research that addresses the large complex space of relevant military UGVs. The intent is not in the design of optimal robots for specific missions, but rather to allow research to occur in the many areas of mobility. High degree-of-freedom UGVs are one area researchers are considering. These systems that start to mirror biological system complexity result in an expectation of animal like performance. However, biological system performance creates ever increasing control complexity for the system. Research in this area is being addressed using the 12 degree-of-freedom hybrid legged/wheeled Micro Hydraulics Toolkit (MHT).

2. INTRODUCTION

This document presents procedures for the operation of the Micro-hydraulic Toolkit, sufficient to give a demonstration of its Leader-Follower capabilities.

3. GENERAL SAFETY CONSIDERATIONS

This section should be read prior to operation of the MHT to ensure safety of the operator as well as the stability MHT’s systems.

a. Should a valve puncture or disconnect during operation of the MHT, stand back from the MHT immediately. Unplug the platform or pull the disabler pull switch if possible.

b. If the MHT exhibits unexpected behaviour, kill the MHT immediately to prevent damage to the robot or the operators.

c. Should the MHT unexpectedly fall over, high pressure fluid may leak. Do not approach the MHT. Do not attempt to break the fall as the MHT weighs approximately 350 lbs.

d. If the joints collide or the MHT falls over, walk around the MHT and carefully look for damage before further operation. Check the connections that may have been pulled beyond physical limits or wires that could have severed.

e. The duty cycles for different components of the MHT have not been fully tested. Take caution while operating the MHT for even more than a minute. Feel the pump to gauge the temperature. Be aware of odours such as burning plastic or silicon.

f. Stay out of the range of motion of the MHT as much as possible. g. It is strongly recommended that there be more than one operator at any given time. This is

especially true while using recording instruments or traversing complex terrain. h. Document all damage, software errors, wiring modifications or any changes to the system in

general and notify other users of the changes. Keep a maintenance log.

MHT UGV OPERATIONS QUICK START GUIDE




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3.1 Kill Switch Operation

There are a total of four switches on the MHT. The kill switches only disable joint and wheel movement, they do not kill all power supplied to the MHT.

While the MHT is in the killed state, the MPC565 controller remains powered to allow the operator to upload code. The vision system is also powered while the MHT is killed as it is not a safety concern.

The two bright red kill switches (shown in the figure below) are located on either side of the chassis. We will refer to these as ‘RKill’ and ‘LKill’ for right kill and left kill. If either switch is pushed, the MHT is in the ‘KILLED’ state.

Figure 1 LKILL (Left) with PSI indicator above, and RKILL (Right).

In addition to RKill and LKill, there are also two pull switches that allow operation from a safe distance from the MHT. There is an enabling switch ‘EPull’ and a disabling switch ‘DPull’ (shown in the figure below). These pull switches have been labeled for clarity.

Figure 2 Pull switches. The enabler (left) has been ejected.




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The pull switches are active when pulled. EPull must be pulled for the system to be ‘LIVE’. As for the buttons, whenever DPull is pulled the system state is ‘KILLED’.

In the figure below, the switch to allow the hydraulic pump to periodically cycle is shown in on/off modes.

Figure 3 Pump on (left), pump off (right)

4. MHT – STANDARD OPERATING PROCEDURE

4.1 Pre-Operation Safety Considerations

a. Inquire as to the status of the MHT with the appropriate personnel. b. Ensure the MHT is KILLED (please refer to Section 3.1, Kill Switch Operation) c. Remove obstacles within range of motion or inside of the planned trajectory. d. Check to see if there are any cables within the range of motion of the hip or knee joints that

may be pulled or severed during joint actuation. e. Ensure that the planned route does not exceed the tether length. f. Ensure all power supplies are off or disabled. g. Charge the Playstation Controller for at least 30 minutes to ensure it will have adequate

charge to last for the length of a demo. This should be done by plugging it into the Linux laptop (which has the driver for the PS Controller installed). All lights on the controller will flash during charging.

h. Unplug the Playstation Controller once it is sufficiently charged (it will not work while it is plugged in).

4.2 MHT Leader/Follower Demo Configuration

For the Leader/Follower Mode Demonstration, the MHT is not connected to the gantry and is free to manoeuvre. It is only limited by the tether length. This is only used for algorithms in the advance design phase that have been thoroughly tested. The following are potential safety concerns for this configuration: a. Rotation of wheels in contact with surfaces can quickly cause the MHT to exceed the

maximum tether length causing wires to potentially disconnect. b. The gantry should remain in close proximity in case something should occur. c. It is highly recommended to have at least two people present for this configuration.




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d. The MHT should be FULLY serviced before attempting this configuration. If the screws for even one joint were sheared it would cause the MHT to lose all torque in the joint and the MHT would slam into the ground and even possibly roll for certain postures.

Figure 4 MHT Leader/Follower Configuration

4.4 Starting ROS This section explains how to bring up the MHT Linux laptop.

a. Verify that the camera is plugged in to the Firewire Card and also that the Firewire Card is plugged in to power. (It has its own power cable)

b. Start up the MHT laptop with all devices plugged in. c. Login using the following passwords:

(1) HDD encryption password: U8=]?%”(2) Ubuntu: mix63^!

d. Open up three separate terminals (or press CTRL+SHIFT+T to create three tabs). e. Place target (purple ball) in the center of the camera’s field of view. f. In the first terminal and type ‘roslaunch mht_vision leader_follower.launch’.g. A window will pop up, hopefully drawing a rectangle around the target. If not, move the

target until it is successfully outlined. h. Once the target is being tracked press Enter.i. The PTU should now move to center the target on the camera. Move the target back and

forth slightly to verify camera lock. If the ball is lost, hit ctrl+c and return to step ‘f’. j. In the next terminal and type ‘roslaunch mht_remote_control remote_control.launch’k. Hit the ‘PS’ button on the PS3 controller. When it rumbles communications have been

established. You may need to stop and rerun this (press CTRL+C to stop) if the controller goes to sleep.

l. In the last terminal type ‘roslaunch mht_communications_protocol mht_comm.launch’.m. Proceed to next section.




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4.5 Supply Power

a. Confirm that the MHT is KILLED. b. Plug in the MHT power and power for the T7500 desktop computer. The user should

remember to always unplug the MHT when leaving for extended periods of time. c. Turn on the board power supply and set to 24.0 V. The board itself draws low current. This

is the small supply on the wooden box, as shown in the left image of the figure below. d. Turn on the hydraulic actuator power supply. Set the output to on, and then adjust the

voltage to 24.0 V. This supply is shown in the left image of the figure below, to the left of the board supply.

e. Turn on the main power supply located on the base of the PC trolley (see center image of the figure below). It should be set to 26.0 V and be able to supply 50.0 A.

f. Turn on black power switch located on the base of the PC trolley (see the right image in the figure below).

Figure 5 MHT Power Supplies

4.6 Upload and Run the Motion Profile

a. Reconfirm that the MHT is KILLED. b. Turn on the MHT’s Hydraulic Pump Switch (refer back to Figure 3). c. Turn on the T7500 desktop computer. d. Open MATLAB and open the *.mdl model file that is to be used for the trial. For the

Leader/Follower demonstration, this should be:

“c:\mht\MHT Final Control\McGill_Controller_PID4_RemoteControlFinal.mdl”

e. Open the associated parameter ‘.m’ file. For the Leader/Follower demonstration, this should be:

“c:\mht\MHT Final Control\MHT_Postures_Task1_1_RemoteControlFinal.m”

f. Run the parameter file by clicking the green arrow button. The script will initialize all the variables required for the model file.

g. Switch back to the model file window. h. Press CTRL+B to build and upload the model to the MHT. CodeWarrior will eventually start

and the following uploading screen should appear.




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Figure 6 Uploading Code to the MPC565

i. Once the program has been successfully uploaded and is running on the MPC565, CodeWarrior will appear as shown in the figure below. Once CodeWarrior is in this state, make sure to UNKILL the MHT in a reasonable timeframe (~5 sec) or the program could behave unpredictably/dangerously. If you miss this 5 second window, it is best leave the MHT killed, abort the CodeWarrior process, and return to step ‘f’ in MATLAB.

Figure 7 Code Successfully Uploaded to the MPC565




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j. Switch the MHT to LIVE mode (see section on kill switch operation). It is imperative the program has uploaded and is executing before switching to the LIVE state. You have less than 5 seconds to UNKILL the MHT when the program begins execution.

k. The MHT will start responding to controller commands within 15 seconds. Please refer to Figure 8 in the following section for control details.

l. While the MHT is running, watch the joints for any unexpected movements and remain in reach of a kill switch at all times. Which kill switch is used depends on the situation and the position of the MHT, however the DPull switch is recommended for safety. If unexpected movement occurs, enable a kill switch immediately.

m. Once the demonstration is complete, press the “Ending Sequence” button (the circle button) on the PS3 Controller to move the MHT into a safe rest position. Once the MHT is in the final position, press a kill switch on the MHT.

n. The MHT will depressurize steadily without power. If the MHT is suspended, ensure the cable is taut to prevent the MHT from falling over.




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4.7 Remote Control

The MHT is controlled with a PS3 six axis controller as shown below:

Figure 8 PS3 Remote Control

a. The left control pad buttons are for setting the mode of operation. b. The right shape buttons and the START button are shortcuts for vehicle positions. c. The left stick is for speed control, the right stick is for steering. d. The centre “PS” button is used to activate the controller once the ROS Controller module is

running. e. The PAUSE button can be used to hold the current vehicle orientation.

5. TROUBLESHOOTING

This section provides solutions to some commonly encountered problems.

5.1 MHT ROS Controller Module - Playstation Controller

If the playstation controller does not work when ROS prompts you to press the PS button, ensure that it has been sufficiently charged (using the MHT Linux Laptop) and it must be unplugged from the laptop in order to work.




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5.2 MHT ROS Vision Module - Firewire Camera

Ensure that the camera is plugged in to the Firewire Card and also that the Firewire Card is plugged in to power.

5.3 MHT Communications Module

The most common error that occurs with this node is the inability to see the USB to serial converter. Make sure all of the connections are tight and the green LED on USB to serial converter is on. One may need to reset the computer due to the dynamic naming conventions of these ports.

mht ugv operations quick start guide · figure 1 lkill (left) with psi indicator above, and rkill...

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