Physicomimetic Motion Control of Physically Constrained Agents

Abstract

Physicomimetics is a simple and scalable means of controlling multiple agents, provided the agents can perform the maneuvers required by the forces applied to them. For most physical agents, such as wheeled vehicles and fixed-wing aircraft, physical constraints such as motor power and stall speed limit the ability of the agents to respond to physicomimetic inputs. We identified four factors, maximum turn rate, controller time resolution, maximum speed and minimum speed, that must be accounted for in the design of the agent model in order to allow good swarming behavior. To address them, we developed an extended body agent model consisting of two particles, one in front of the vehicle’s rotation center and one behind. This allowed us to explicitly determine the agent’s direction of motion and, combined with nonlinear checks to avoid unachievable commands, allowed us to develop agent models whose behavior was still intuitively controllable and analyzable but which respected the constraints of our physical robots. We also defined a dynamic friction term that penalized speed in cluttered environments and excessive or unstable oscillations to address the fact that under asynchronous distributed control no single set of friction parameters worked in all cases.