Study on Self-Position Estimation and Control of Active Caster Type Omnidirectional Cart with Automatic / Manual Driving Modes

This paper presents the development of an active caster omnidirectional cart with manual/automatic modes. The proposed cart realizes holonomic and omnidirectional motions using dual-wheel active casters. Since the active caster has the same wheel structure as the passive caster, the active caster functions as a passive caster by disconnecting the drive shafts from the motors in the manual mode. In this mode, the cart can be moved by pushing and pulling by hand. Further, even in the manual mode, the movement of the cart by a human can be accurately recorded by measuring the rotation of the wheels and the steering shaft. In the proposed system, the operation of the cart manually moved is recorded, and playback of the motion by automatic driving is performed. This is a kind of teaching/playback system for carts. This function enables easy teaching of cart trajectories and accurate positions. This paper describes the mechanical design and control method of the omnidirectional cart, followed by the experimental results of the prototype omnidirectional cart.