Achieving Smooth Motion for Piezoelectric Stick Slip Actuator with the Inertial Block Structure

A piezoelectric stick slip actuator with the inertial block structure is presented in an attempt to achieve smooth motion. Under asymmetric excitation, the inertial block produces different inertia, which can dynamically change the normal pressure between the stator and rotor to adjust the friction. During the slip stage, the driving arm produces a deflection away from the rotor, the normal pressure between the stator and rotor can be eliminated, and the angular impulse of the moment of friction force on the rotor can be almost reduced to zero. To verify the feasibility of the prototype, finite element method (FEM) simulation is performed. On the basis of the experimental system, the output characteristics of the prototype are systematically studied. The experimental results indicate that the prototype can achieve smooth motion under large pre-tightening displacement. The displacement curve under the load of 2.0 kg still shows good smoothness, and the resolution is 1.56 rad. This work proposes a new design concept of dynamic control of the normal pressure to achieve smooth motion for piezoelectric stick slip actuators, even under heavy-load conditions, using the inertial block structure.