Kinematic analysis of a gripper actuated by shape memory alloy springs

The gears and motors for driving grippers are replaced by a pair of differential shape memory alloy(SMA)springs and a proportional integral(PI)controller to actuate the gripper.The gripper mechanism is a six-bar linkage composed of two II grade linkage groups and a drive link.A kinematic model is developed for the gripper using the Assur-group method.The model results are combined with the results of PI control experiments to analyze the kinematic properties.The results show that the SMA gripper with the PI controller provides a stable trajectory of the fingers.