A Novel electrical variable stiffness device for vehicle seat suspension control with mismatched disturbance compensation

This paper presents a novel electrical variable stiffness device (EVSD) and its application in seat suspensions. The EVSD is inspired by the conventional mechanical variable stiffness device (VSD) and the force-current analogy, which applies an inductor and a variable resistor to simulate the functions of the spring and variable damper in the mechanical VSD. The electrical system has less physical limitation than the mechanical one in the practical application. Besides, the EVSD requires no power supply except for control signals at milliwatts level. The test result shows the stiffness controllability of the proposed EVSD and matches with the system model in the simulation. Seat suspensions have been extensively utilized in vehicles, especially heavy-duty ones, to protect drivers' health and improve the ride comfort. An EVSD-based seat suspension is investigated in this paper. The seat suspension applies the suspension deflection, circuit current, and seat acceleration, which are all easy to measure with sensors, as feedback to estimate the mismatched disturbance in the system; and a H ∞ controller with compensation of the mismatched disturbance is designed for the seat suspension. The experiments validate the effectiveness of the proposed seat suspension and controller. This EVSD-based seat suspension consumes ignorable energy and has great potential in practical applications.