Robotic Devices for the Transit Environment (2003)

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13 Main camera display AVAILABLE ROBOTIC SYSTEMS Introduction to Robotic Systems A robotic system consists of a vehicle to carry a payload and an operator control station (OCS) for tele-operation. The vehicle is designed for specific mobility needs such as high-speed travel, traversing rough terrain, and/or maneuvering in small spaces. The payloads are typically a manipulator or an end effector on an arm, sensors, and actuators. Payloads could include an X-ray camera, chemical-agent detector, drug-detection devices, bomb-disarming systems, and so forth. The OCS displays feedback from the vehicle, typically video, and provides controls to operate the vehicle. Robot Vehi Operator Contro Radio transceiver Manipulator arm a Track/wheel system End effector/gripper Steerable camera & lights Manipulator camera Wrist joints (2) Turret & shoulder joints Elbow joint Body (Electronics bay) Path lighting Command interface Path camerAuxiliary camera display Data display Joystick interface Protective carrying case cle l Station By permission of EOD Performance

14 Robot Vehicle Features Robot vehicle features include the subsystems that enable the robot to perform missions as a tele- operated vehicle. These include the subsystems that provide mobility and remote-object manipulation. They also include the subsystems that provide operator feedback for controlling the vehicle remotely. Mobility System The mobility system consists of tread tracks or wheels powered by drive motors. Some vehicles have track extensions that add additional tread length to either lift the vehicle for additional arm height or aid in stair or obstacle climbing. The track length and the slope of the leading pulley arrangement determine the pitch of stairs that the vehicle can climb. However, vehicles with longer track length are less able to turn in tight quarters. Vehicles are capable of turning about their center (zero-radius turn) by driving the tracks in opposite directions. Wheels can be added for faster speeds on smooth or paved roads. Typicall bolted onto a hub of the track system, raising the treads from contacting the g extensions or wheels should be remotely deployable. Manipulator Arm The manipulator arm is for moving payloads. An e gripper, is used in applications such as placing sen and for dexterous movements such as opening a positioning equipment. A further use is to extend vehicle by mounting a camera on the end of the ma done, for example, to look into overhead lugga manipulator should have at least 5 degrees of free effector can be moved in any of the three coordina around both a vertical axis and a horizontal axis. T motorized joints in the manipulator-arm links “shoulder,” “elbow,” “wrist twist,” and “wrist rotation.” The gripper shou between the “fingers” and grasp a cylindrical object such as a pipe bomb. Vehicle Control Systems Robotic device control electronics can be a proprietary processor, a standa standard personal computer (PC) processor. Among these processors there weight, flexibility, and expandability. The proprietary processor is the least the least flexible, and the least expandable of the processors, and the PC expensive, heaviest, most flexible, and most expandable of the proc expandability are desirable for future enhancements, features, and option processor a good choice if the cost and weight of the overall robotic d requirements. Further, the PC processor uses a more common programming la making it more universally serviceable on an engineering level if custom func The communication link is a major subsystem in vehicle control. Several sc data use relatively high bandwidth (5 MHz) for frame rates sufficient to whereas commands and audio and sensor data require less bandwidth (20 KH techniques is to use two transceivers, one high-frequency channel for the typically 2.4 GHz, and the other a low-frequency channel, 900 MHz for exa low data rate of the commands. FM transceivers are common, and video data loss that causes pauses or jumping of the picture. The second technique uses a a wireless Ethernet 802.11 protocol. This technique is a digital By permission of EOD Performance tBy permission of iRoboy, wheels are manually round. Ideally, the track nd effector, typically a sors or retrieving items door, using a tool, and the visual range of the nipulator. This might be ge compartments. The dom, meaning the end te directions and rotate his is accomplished by including a "turret," ld be able to squeeze rd microprocessor, or a are differences in cost, expensive, the lightest, processor is the most essors. Flexibility and s. This makes the PC evice meets necessary nguage than the others, tionality is desired. hemes are used. Video prevent jerky motion, z). One of two popular large video bandwidth, mple, for the relatively are susceptible to signal single transceiver with transmission method,

and loss of signal is not as noticeable. This transmission uses spread spectrum modulation, in which the video is carried on the main frequency, and the other data use a sideband. This technology is more adapted to a PC controller and is not as widely deployed as the other types of controllers. In addition to radio frequency links, cable tethers are used. Two types are available, optical-fiber and wire cable. Optical fiber is generally smaller and more lightweight than wire, and it has higher bandwidth to support longer transmission distances. The fire control system, although a minor feature for most missions, is noteworthy because of the safety concern. For firing bomb disruptors, the fire control circuit should be failsafe with the use of at least two actuations from the control station and at least two mechanical switches that cannot fail at the same time in the fire position. Robotic systems must operate in environments with extreme temperatures. Further, the vehicle itself produces heat from the controller and drive motors. The vehicle’s electronics bay should be equipped with a temperature control system that usually cools the device, but can also heat it. Video, Lighting, and Audio Systems At a minimum, the vehicle needs a forward-looking camera for the operator to see the path. Generally, robotic devices have a number of cameras to provide good situational awareness and other specific cameras to provide detailed viewing. Typically, there is a steerable color camera or a 360-degree panoramic camera. Additionally, a manipulator-arm mounted camera provides “snooping” capability or can be used to aim disruptors. One or more of these cameras should have zoom capability, typically 10X or greater optical and 100X or greater digital. However, digital zoom capability sacrifices resolution and is not By permission of Mesa Association.15 recommended at extremely high powers. All cameras should have auto focus and either mechanical or electronic auto iris capability. The typical resolution of these cameras is 320 x 240 at 15 frames per second (FPS). Lighting is generally provided for each camera. Lighting should be dimmable from full brightness to off. High-intensity white light-emitting diodes (LEDs) are used for weight and energy savings. Infrared lighting and cameras are occasionally used. Vehicle audio capability usually includes a microphone and speaker. Audio compression is employed to reduce signal transmission bandwidth and provides a sound quality similar to portable telephones. Modularity and Compatibility For serviceability as well as transportability, the ability to remove the tread track assemblies and the manipulator-arm assembly from the body (usually the electronics bay) is desirable. These should be self-contained assemblies attached with a few captured fasteners and cables with electrical connectors that plug into a bulkhead on the body. The electronics in the body bay should ideally contain plug-in circuit boards similar to a PC. Fastener-mounted circuit boards with cable connectors are an alternative. Other electronics, such as power supplies, motor controllers, and so forth, should also be easily removable. The electronics should be designed so that the field-replaceable units are at a subassembly level no lower than a circuit board or off-the-shelf item and a level no higher than a removable electronics rack in the robot body. The vehicle battery should be changeable in a few minutes without the use of tools. Multiple batteries should be used if necessary to keep the weight of each battery pack under a few pounds. A vehicle carrying case should be a standard accessory. Compatibility has several elements. Modular features on robotic devices should be interchangeable among vehicles. Also, the components should be readily available from several sources whenever possible. Batteries, PC components, cameras, lights, and so forth should be designed to use consumer products when practical. Finally, a vehicle should be controllable from any control station with the proper radio frequency set-up. Controllers and vehicles should have a selection of broadcast channels that allow fleet control without interference. A software protocol standard has been set forth for military robotic devices with the objective of enabling any manufacturer’s controller to command any other

16 manufacturer’s vehicle. This is the Joint Architecture for Unmanned Ground Systems (JAUGS). This protocol is being required in military contracts, but is in its infancy; no commercial cross- manufacturer control has yet been demonstrated. Sensor, Actuator, and Other Auxiliary Devices Payloads such as sensors and actuators typically have electrical data outputs or actuation command inputs that must be communicated to or from the OCS. These signals must therefore interface with the robotic vehicle. Standard communication protocols and hardware are primarily used, and, therefore, the robotic vehicle should have one or more RS232 (a wiring protocol), Universal Serial Bus (USB), or Ethernet ports. It should have power jacks, typically 12 VDC, for external devices, as well as a battery-charger jack. There should also be quick-connect firing circuit terminals such as “radio speaker jacks” capable of handling 2 amps of current. Operator Control Station Features The OCS features include the subsystems that provide the ability to control the vehicle and payloads to perform the mission. Direct controllers include the subsystems that provide the man- machine interfaces for remotely controlling the robotic device and getting feedback. Mobility Control There are several techniques for controlling robotic motion. Two of the more popular techniques are “direct” control and “proportional” control. Direct control provides “go” and “stop” commands, and the robot moves at a given speed. These controllers usually provide the ability to select from three speeds, for example, slow, fast, and very fast. Reverse is also provided. The go, stop, and speed commands on the simplest controllers are issued with single keystrokes or buttons. Turning commands are likewise initiated with keystrokes: a single stroke is a little turn and several strokes are a sharper turn. Proportional controls have continuously variable speed and steering adjustments in which the motion is proportional to the movement of the interface device, typically a joystick or PC mouse. If the interface device is moved a little forward, the vehicle moves slowly forward. If the interface device is moved a great deal to the left, the vehicle moves at a fast speed in a sharp left turn. This user interface is well known from video games. A proportional control system is more intuitive and requires less effort and concentration to use, but is typically more expensive. Manipulator Control The manipulator is typically commanded using a direct control system at a fixed speed. The interface device can be keystrokes, buttons, or a joystick. Here, the interface type makes little difference because the commands are discrete motions such as arm left/right, arm up/down, arm in/out, gripper open/closed, and so forth. Most of the links and joints in the manipulator provide circular motions so that arm commands are not strictly up/down or in/out. An up command, for example, is actually a shoulder-joint command that is a rotary motion. The arm also moves a little in or out as well. Therefore, when navigating to a precise target, like a key in a lock, a difficult iteration of commands is necessary. In more elaborate controllers, this is alleviated by the controller calculating the combination of motions required to move the gripper in a straight line. With a system like this, the user can command linear motion. A further refinement is the ability to use a coordinate system. The operator could define a zero X, Y, Z location and then command the gripper to go to a measured location using keyboard-entered coordinates.

17 Video, Lighting, Audio, and Navigation Control The control of functions in the video and lighting systems is basic, particularly controlling the lighting and the direction of the steerable camera(s), often referred to as the "pan/tilt" camera(s). These systems' display of information is of greater importance because they are the eyes and ears of the operator. As mentioned earlier, there are typically three cameras with corresponding lighting. The operator display console should display images in such a way that the operator is aware of all the data without being overwhelmed. The best display technique is a thumbnail image from all cameras and a large main display of one image. The operator should be able to select a desired image from the thumbnails and display it by pushing a button or selector switch. Camera iris control should be automatic, with an operator switch and/or knob for manual operation. Camera auto-focus control is internal to the camera and generally not accessible by the operator. The video display should be daylight readable with backlighting for night viewing. Two-way audio should have a toggle switch (stays on or stays off) for listening and a momentary switch (must be held on) for talking. For both audio and video, the controller should have output jacks for recording on external devices. Navigation systems that provide the operator with robot location and heading are used on the more advanced systems. These tools include electronic compasses, global positioning systems (GPSs), range-finders, and so forth. Other Features Disruptor fire control should be controlled with two cover-protected switches. One switch arms the circuit, and the other switch fires the device. For added safety, there may also be a software command; however, the arm and fire controls should be mechanical switches. The OCS should be battery powered with a jack to recharge the battery or power the controller. There is often a jack for an external high-powered antenna. The OCS enclosure should be a lightweight portable unit that is watertight for use in rain or decontamination. A backpack should be an optional accessory.

18 Available Systems Numerous commercial off-the-shelf (COTS) robots are available in a range of sizes and abilities. Vehicles range from units small enough to be thrown, which are used strictly for surveillance, to large all-terrain vehicles (ATVs) for carrying or towing huge payloads. This report illustrates a selection process for small to mid-sized robot systems only. This is based on a cursory examination of the transit requirements of the previous section. These robot systems will meet most of the terrain and obstacle requirements, specifically size and weight requirements for the defined environment, as well as man transportability requirements. Also, these robot systems are priced within the budget of an organization equivalent to a local government agency. Further, this report focuses on selecting a single multipurpose system meeting the most number of requirements, rather than selecting a family of robot systems spanning all requirements, because owning a family of robotic devices is not within the budget of most transit organizations. Therefore, a list of small to mid-sized candidates is compiled in Table 2, and their fit to transit requirements is discussed in the section on selection analysis. CANDIDATE ROBOT CRITICAL FEATURE TABLE Table 2 Manufacturer Name of Robot Country of Origin Vehicle Weight OCS (lb) Length (inch) Width (inch) Height (inch) Drive & Speed (mph) Control Link* & Range (miles) Arm Lift Extended (lbs) Arm Lift Retracted (lbs) Reach Horiz. Vert. (inch) Stair Climb Max Grade (deg) Cost ($K) Cyclops L.E. UK 59.5 34.5 15.6 8.25 Track 1 Cable 1.1 11 Y 85 Cyclops Mk4C UK 88.2 34.2 19.3 8.25 Track 3.4 RF 8.5 FO 11 Y 120 Lynx UK 39.7 25.5 17.75 17.75 Wheel 1.2 Cable .28 N 25 Groundhog UK Wheel RF N 58 AB Precision (Poole) Ltd. Bison UK Wheel RF N 88 Intruder USA 42 22 17 10 Rollers 1 RF .6 No Arm No Arm No Arm N 6-8 10 Angelus Research ART USA 40 22 13 7 Track 1 RF .9 No Arm No Arm No Arm N 6-8 TSR 202 FR 594 47.25 26.4 39 Track 2.5 RF 2.2 Cable 1.3 26.5 154 93.6 Y 40 150 Track Castor Wheel FR 92.6 61.7 31.4 26.8 15.7 15.7 15.7 16.9 Track 1.5 Wheel 1.5 RF 2.2 Cable 1 11 22 43 Y N 30 Cybernetix (Giat) Track RM 35 Wheel FR 165 33.1 23.3 19.7 Track 1.7Wheel 1.7 RF 2.2 Cable 1.3 11 31 57 N 30 EOD Performance Vanguard CAN 95 36 17 16 Track .75 Wheel RF Cable .75 20 40 38 52 Y 38 25 Engineering Tech. Inc. RATLER USA 33 22 19.6 12 Wheel 2.3 RF 5.2 No Arm No Arm No Arm N Talon USA 85 34 22.5 11 Track 4 RF 1 FO 30 40 53 Y 45 60 Solem USA 48 20 14.75 8 Track 1 RF 1 No Arm No Arm 23 Y 45 41 Foster-Miller Ferret USA 480 57.5 26.5 57.5 Track 1.5 RF .4 Cable HDE MFG MURV-100 USA 49.6 23.8 17 4.5 Wheel .8 RF 5 FO 20 35 60 N 25 HighCOM Security MR-5 CAN 550 50 26.7 31.5 Track 7.3 Wheel 7.3 RF Cable .1 44 130 67 95 Y MicroVGTV USA 12.5 6.5 2.5 Track .2 Cable .02 No Arm No Arm No Arm N 15 Inuktun MDV USA 90.4 23.6 14.2 16.6 Track .4 Cable .56 No Arm No Arm No Arm N 40 iRobot Icecap USA 52 24 20 6.5 Track 4.9 RF .4 FO 1.3 TBD TBD 78 Y 60 85

19 (Table 2 continued) Manufacturer Name of Robot Country of Origin Weight Vehicle OCS (lb) Length (inch) Width (inch) Height (inch) Drive & Speed (mph) Control Link* & Range (miles) Arm Lift Extended (lbs) Arm Lift Retracted (lbs) Reach Horiz. Vert. (inch) Stair Climb Max Grade (deg) Cost ($K) Brat IRE 125 Track 121 Wheel 35.4 20 20.9 Track 1.5 Wheel 4 RF 1.7 Cable 13.2 18 47 Y 42 wheel 45 track 62 Hobo IRE 502 57.8 27.6 34.7 Wheel 2.5 Cable 1.4 66.1 165 59 Y 42 120 Rascal IRE 72.8 31 16.2 13.6 Wheel 1.6 RF 1.7 Cable No Arm No Arm No Arm N 35 48 Kentree Imp IRE 165.3 31.4 16.6 Track .45 RF 1.7 Cable 11 22 Y 45 62-70 Mesa Associates MATILDA USA 98 26 20 12 Track 2.1 RF 1.4 25 25 42 Y 45 66 MPR 150 USA 218.3 38 23.5 31 Track 1.5 User Spec.9 60 Y 90 OAO Robotics (Lockheed- Martin) Recorm USA 99.2 37 24 25 Wheel 3 User Spec. 9 150 RMI 10 CAN 141.1 32.3 21.6 19.7 Wheel 2.5 RF 1.7 Cable 75 75 77 118 N 45 50 Pedsco RMI 9 CAN 264.6 41.3 24.4 26.8 Wheel 2.5 RF 1.7 Cable 180 180 140 144 Y 45 60 Andros F5A USA 550 35.3 27.6 41 Track 2.0 RF 4.3 Cable 60 100 64 92 Y 45 75.5 Andros F6A USA 350 49 17.5 44 Track 3.5 RF 1.7 25 60 48 84 Y 45 63.4 Andros Mini USA 190 42 24 37 Track 1.1 RF 1.1 FO 15 40 45 87 Y 45 60 Remotec (Northrop Grumman) Wolverine USA 597.4 57.2 27.6 39.4 Track 2.0 RF 4.3 60 100 64 100 Y 45 66.4 Ricardo Brawn UK 440.9 24.4 29.5 33.8 Track RF FO 50.7 51 ROV Tech. SCARAB IIA USA 125 35 14 10 Track .57 Cable .22 Y 87 Predator USA 520 39.6 29 25 Wheel RF 1.6 Cable 40 Merlin USA 60 30 17.3 15.6 Track RF .5 Cable 20 25 Terra A.C. Scorpion USA 55 30 16.2 9 Track RF .5 Cable NA NA 15 * Control link is the link between the operator control station and the robot vehicle. “RF” is radio frequency, “FO” is a fiber-optic cable, and "Cable” is a wire cable. The RF distances are line-of-sight.