Robust force sensorless control in motion control system

This paper describes robust force sensorless control system in motion control. Motion control technology has been contributed to a variety of industrial applications. The achievement of force control is one of the deep technical issues in motion control and industrial applications. Force control has been researched for more than four decades. Generally, force sensor has been utilized in force control. However, force sensor has certain disadvantages and prevent realization of precise force control. Especially, sensor noise causes degradation on control performance. Thus, force sensorless control has been developed. Here, this paper observes both performance of force control system with force sensor and force sensorless control system by the experiments. In addition, this paper classifies external force into reaction force and action force. Most force control system is the target of reaction force control. However, action force control system is required to adopt to more variety applications. Thus, at first, reaction force control system and action force control system is described. In addition, the relationship between both force control system and control stiffness is expressed. Control stiffness is a performance index of motion control. Control stiffness is then used to evaluate the performance of both force control system. Experimental results are presented the behavior of reaction force control and action control.