Pseudo-active actuators: A concept analysis

The superior performance of active vibration control systems largely depends on the four-quadrant controllable execution capability in the available force-velocity diagram of active actuators. Although semi-active vibration control systems have the advantages of low energy consumption, simple structure, and high reliability, the system performance is not comparable to active control systems, due to the partial capability in only the first and third quadrants. On the basis of the comprehensive advantages of active and semi-active actuators, to reform the design philosophy of semi-active actuators to realize pseudo-active actuators that have both mechanical properties of active actuators and energy consumption advantages of semi-active actuators, that is, new semi-active actuators with four-quadrant controllable execution capability, will very likely cause a revolution in the related fields of mechanical design and system control. The basic design principle of pseudo-active actuators that use semi-active controllable actuators to achieve active actuator performance in the way of conceptual analysis is proposed. The proposed pseudo-active actuators should consist of two half-four-quadrant actuators, that is, one is for the first and third quadrants and the other one for the second and fourth quadrants. This study employs two semi-active controllable damping actuators and one mechanical compensation mechanism. One of the actuators provides the damping force in the first and third quadrants, and the other one combining with the mechanical compensation mechanism is for the second and fourth quadrants. A global mathematical model of the proposed actuator is established to describe the four different operational modes of the proposed actuator. It is proved that the two operational modes of the proposed actuator can realize active vibration control, and a case study of realizing active control is presented. The other two operational modes are compared with the conventional two-degree-of-freedom model. More specifically, the application cases of the pseudo-active operational mode of the proposed actuator in the quarter-car/body-powertrain suspension system are given, a pseudo-active suspension named dual-hook automobile suspension is presented. Furthermore, an equivalent expression of the electrical network is given for the mechanical network under different operational modes of the proposed actuator.