High Performance Harmonic Actuator Using Piezo-Compliant Mechanism

Modern robotic applications utilize a myriad of actuator types to meet the different task requirements. The primary actuator types include electric, hydraulic/pneumatic, Shape Memory Alloy, and piezoelectric. Most, if not all, current robotic actuation methods have limited power density for supplying the large forces, displacements, and bandwidths required. Electromechanical and hydraulic systems are examples of current high-torque low-speed solutions, but they add significant component complexity, and weight to meet the stringent load and rate requirements. Ideally, a high-torque and low-speed actuator with minimal cost, weight, and complexity would be favored for robotic applications. The power and bandwidth capability of a DC actuator is a good candidate, but the necessary addition of a gear head reduces the system power density. Likewise, piezoelectric stack actuators boast very high power density, but the available displacement is very limited. Therefore, FlexSys proposes development of a Harmonic Actuator, a novel high performance (high-torque and low-speed), high power density, and compact electrical actuator for demanding robotic applications.