FIELD AND SPACE ROBOTICS LABORATORY
Model-Based Control of High Speed Rough Terrain Robotic Vehicles
Iagnemma, Research Scientist
High-speed mobile robots have many potential applications, including military reconnaissance and scientific exploration. Our project is focused on developing the control and planning algorithms for high speed autonomous rough-terrain ground vehicles. Currently, state of the art high-speed autonomous rough-terrain robotic vehicles travel at speeds of about 10 mph on relatively gentle terrain. Our goal is to develop a system for traversing rugged, desert-type terrain at substantially higher speeds, tolerating vehicle slip and ballistic motion.
Full-scale high-speed off-road military vehicle
Artist rendition of high speed robotic
vehicle in rough terrain
The focus of Year 1 for the project was to begin initial development of a low-level control scheme, and to develop an experimentally validated model of a representative high-speed rough-terrain vehicle system. A small tele-operated vehicle was built for this purpose. The vehicle dynamics were identified, modeled, and subsequently simulated using a commercially available dynamics solver package. The simulation results compared favorably to the experiments. Below are images from our rough-terrain vehicle simulation.
Wireframe view of simulation model
We are also investigating various low-level control schemes in simulation, and in the future, experimentally. These schemes will be used for velocity and heading control in rough terrain at high speeds. Low-level control will be combined with other control and planning layers to enable robust, fully autonomous behavior.
We have built two experimental systems for this project – a small 1/10 scale vehicle for model validation experiments, and a larger, 1/4 scale vehicle for autonomous control experiments.
Above is a picture of the 1/10 scale system built modeled for validation purposes. The vehicle is tele-operated, and fitted with a three axis accelerometer and data-acquisition equipment for recording the dynamic response. The two-wheel drive vehicle is commanded torque to the drive wheels, and front wheel steering angle. The wheels are driven by an electric motor through a rear differential. The vehicle is about 14 in long, and weighs about 3 kg.
Artemis "undressed" on the astroturf
Artemis internal schematic
We are building a 1/4 scale high speed rough terrain testbed called Artemis for testing and demonstrating control and planning algorithms in real time. Artemis is about 48 inches long, current wheel diameter of about 7 inches, and weighs about 15 kg. The vehicle chassis, suspension, and drivetrain were custom made to our specifications by Weller Racing. With no payload, the vehicle can travel up to 50 mph, and survive drop offs of over 6 feet. Components and systems:
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