The ATR 6000 is a fully operational tracked mobile robot. It is a stable robotic platform capable of operating autonomously in a foreign, rugged environment. The robot navigates between known milestones in the presence of initially unknown obstacles and unknown topography. While operating in this environment, the robot senses and maps obstacles, and charts obstacle-free paths. Based on this real-time mapping effort, the robot then plans and executes a trajectory to the next milestone. It also stores and recalls obstacle locations from previous maps and reassesses its own location in the environment. Routines for dynamic motor control and collision-avoidance guarantee smooth and safe navigation to the final goal.
The ATR 6000's robust, tank-like design employs a dual flexible-track system to conquer difficult terrains and steep slopes. Each track is equipped with its own suspension system. The robot can move at speeds as high as 3.6 ft/s. It can pivot about its center and make sharp, accurate turns.
The ATR 6000's dimensions are 32" long, 24" wide, and 24" high. It weighs 150 lbs and is constructed in three major parts: lower chassis, upper chassis, and sensor turret. The lower chassis contains the robot's propulsion, suspension, and electrical power systems. The upper chassis houses all computer and electronic processing equipment, including user-interface devices (a keypad and two liquid crystal displays). The eight-sided sensor turret, which can be rotated 45! in each direction, is used to detect distant obstacles.
Currently, the ATR 6000 perceives its environment through forty-two chassis-mounted and eight turret-mounted ultrasonic sensors. The chassis-mounted ultrasonic sensor array, used for short- and mid-range obstacle detection, is augmented by a tactile sensor array. The turret sensor array, used for long-range sensing, can be rotated to sweep the environment and quickly gain information on obstacles located up to 32 feet away. A stereo-camera vision system is under development to complement the turret-mounted ultrasonic array.
Computations are executed by two on-board computers operating in parallel. They are an 80386DX 33 MHz motherboard and an 80486DX2 66 MHz motherboard. Each microprocessor controls a distinct input-output (I/O) card. A TMS320C30 microprocessor is used for internal signal processing. The software structure is designed for evaluation and comparison of different algorithms for mobile robot locomotion (e.g., map making, path planning, and path following).
In addition to their role in mobile-robot research, machines like the ATR 6000 can be used for inspecting and handling of materials in hazardous areas, manufacturing, construction, structural-integrity tests, and counter-crime applications. The robot can be equipped with portable sensing devices and actuators and programmed to sense its environment, record data, and perform specific tasks. Typically, such tasks are either too monotonous or too dangerous for humans to perform.
In addition to the stereo-vision system, current plans for the robot include the addition of a deployable mechanical arm that will increase the robotUs capacity to do useful work once it has arrived at a milestone.
Members Working on the ATR
Original Design/Construction: Brian Callahan, Gary Cane
Original Design Advisor: Joe Prosser
Additional Programming and Research: Javier Elenes
Stereo Vision: Gabe Fielding
Arm Design: Bill Bassill