A set of piezoelectric actuators weighs 4 to 50 times less than other robotic actuators in end-effectors, including hydraulic or solenoid devices. The small piezos use ultra-low power: 3 mA holding current at 6.8 VDC, 7.5 mW. The piezo technology is a scalable actuator moved by a pre-loaded piezo stack. One- and two-armed versions are available.The devices produce no electromagnetic field or EMI/RFI. The actuators, therefore, can be used in semi-autonomous robots that may rely on weak RF signals for positioning or guidance. The piezos, which also can operate as transducers, have demonstrated a life of three billion cycles in non-robotic applications. They can be scaled to suit requirements.