Control of Human-machine cooperative cart by region attractor to achieve both obstacle avoidance and trajectory tracking

Abstract

In this paper, we propose a control system design method for a human-machine cooperative system in which a human and machine cooperate to propel a cart to a reference trajectory. In the previously proposed method, the human plays the role of recognizing the environment and determining the propulsive force, while the machine determines the steering angle based on the position and posture of the cart, using a vector field with the reference trajectory as the orbit attractor. However, since this method cannot avoid obstacles on the trajectory, we extend it to a region attractor. By setting an index variable that changes depending on human input, the vector field is designed in the extended dimensional space including the index variable, and the cart can avoid obstacles by moving within the region defined by the reference trajectory with its parallel trajectory depending on human input. In this paper, we describe (1) the design method of the reference trajectory and the parallel trajectory considering the workspace of the steering and the distance between the cart and the wall, (2) the design method of the region attractor in the extended dimension including the index variable, and (3) the experimental verification of the proposed method.

Keywords

• trajectory tracking
• obstacle avoidance
• human-machine cooperation
• region attractor
• nonholonomic system
• mobile robot