Acceleration feedback-based Low-level Control of an Active Seat Suspension System

The mechatronic system of the automotive active seat suspension system considered in the paper comprises an electric servomotor, a spindle mechanism, a nonlinear Scott-Russell linkage, and the seat structure. The overall control strategy is structured into two layers: a high-level controller responsible for generating the seat force reference, and a low-level controller aimed at accurate tracking of the force reference. The emphasis is on the design of a low-level control system employing a vertical seat acceleration feedback controller for effective friction compensation. Two variants of the control strategy are proposed depending on how the transmission nonlinearity is handled: (i) gain scheduling control, and (ii) input linearization-based control. The performance of the proposed low-level control system is evaluated through numerical simulations, both individually and within the full control framework incorporating a linear quadratic high-level controller.