Self-moving cell linear motor using piezoelectric stack actuators

In this paper, a self-moving cell linear motor (SCLM) using a piezoelectric stack actuator is designed, manufactured, and evaluated. The self-moving cell consists of an oval-shaped shell structure and piezoelectric stack actuator. The self-moving cell concept is different from a conventional inchworm linear motor because the SCLM has unified clamping and push devices. The clamping force of the SCLM is determined by the interference dimension and the friction between the shell structure and guideway. Thus, this motor can generate a large clamping force and maintain a fail-safe lock. The most important part in designing the SCLM is the shell structure. Finite element analysis and the Taguchi method are used to optimally design the shell structure. The performance of the SCLM is tested in macro- and micro-motions. In macro-motion, the SCLM exhibits the maximum speed of 100 μms^-1 and the blocking force of 3.7 N. Since the load capacity of the motor is determined mainly by the friction force between the shell structure and guideway, a large load can be maintained at low speed. In micro-motion, PID control is used to overcome the hysteresis of piezoelectric stack actuators and the possibility of precise tracking control of the desired trajectory is demonstrated.