Force control of a SMA actuated gripper by using self tuning fuzzy PID controller

Shape memory alloys are widely used in the fields of robotic systems. They have many advantages such as high power-weight ratio and frictionless and quiet operation. But hysteresis phenomenon is an unsightly effect of shape memory alloys that its compensation is a momentous task in controlling them. We used a self-tuning fuzzy PID method for the force control to compensate it. This method is applied on a three fingers gripper that used shape memory alloy as actuator. At first, the method applied on the model of the gripper by co-simulation of MATLAB and MSC.ADAMS. Afterwards, the controller schema is developed on the physical prototype of the gripper and its efficiency is investigated. The experimental results show the good performance of designed controller for force tracking of the gripping force.