Study on an Active Controlled Caster for Carts with Low Crash and Vibration

In recent years, it has been increasingly necessary that patients, medicines and small precision parts should be carried smoothly and quietly by carts with advanced casters. This paper presents experimental and simulational results of a cart with an active controlled caster to reduce cart’s crashes and vibrations. First, the active controlled caster is introduced, which has a mechanical low-crash structure based on the idea of center of percussion. Next, the dynamical model of the cart with the caster is derived to study the caster control of the low crashes and vibrations. This model also includes the road model with a bump and the actuator model for the control. Then we show some experimental results of the cart with the controlled caster, compared to the simulation results. The proposed control is verified to effectively reduce the impulsive crashes and vibrations of the cart. Finally, we in brief discuss the control effect from the view point of the transfer functions and Bode gain diagrams of the cart model.