Pseudo-Active Actuators With Positive-Negative Dampings

Although semi-active actuators have the advantages of low power consumption, simple structure, and high reliability, their output force and excitation are always in the same direction, and they can only achieve mechanical properties in the first and third quadrants of the force-velocity diagram. Thence, the performance of semi-active actuator-based systems is incomparable to that of active actuator-based systems. Inspired by the concept of “four-quadrant operation” of active actuators such as motors, this paper proposes the configuration and principle of a pseudo-active actuator with four-quadrant controllability performance. The proposed pseudo-active actuator consists of two secondary semi-active damping actuators and a mechanical compensation mechanism, which can conditionally achieve the characteristics of arbitrary adjustment within the four quadrants of the force-velocity diagrams. Through the mechanical compensation mechanism, the output force of the first semi-active actuator is the same as the excitation direction, and the output force of the second semi-active actuator is opposite to the excitation. Tuning the inputs of the two semi-active actuators allows real-time and continuous control of the mechanical outputs of the pseudo-active actuators in the four-quadrant diagram. Based on the structural principle of the pseudo-active actuator, the mechanical properties of the pseudo-active actuator are analyzed. An experimental test bench is established to verify the controllable mechanical properties of the pseudo-active actuator prototype.