Adaptive control of an active seat for occupant vibration reduction

Abstract

The harmful effects on human performance and health caused by unwanted vibration from vehicle seats are of increasing concern. This paper presents an active seat system to reduce the vibration level transmitted to the seat pan and the occupants' body under low frequency periodic excitation. Firstly, the detail of the mechanical structure is given and the active seat dynamics without external load are characterized by vibration transmissibility and frequency responses under different excitation forces. Owing the non-linear and time-varying behaviour of the proposed system, a Filtered-x least-meansquare (FXLMS) adaptive control algorithm with on-line Fast-block LMS (FBLMS) identification process is employed to manage the system operation for high vibration cancellation performance. The effectiveness of the active seat system is assessed through real-time experimental tests using different excitation profiles. The system identification results show that an accurate estimation of the secondary path is achieved by using the FBLMS on-line technique. Substantial reduction is found for cancelling periodic vibration containing single and multiple frequencies. Additionally, the robustness and stability of the control system are validated through transient switching frequency tests.

Comfort Level Refinement of Military Tracked Vehicle Crew through Optimal Control Study

“…Such a cost-efficient solution of locally reducing the vibration response i.e at seat level for comfort level improvement is also supported by Gan 23 , et al, who stipulate that, cancelling the vibration at seat itself is gaining impetus now-a-days, due to the reasons that: (i) seat is the part to which the vehicle occupant makes direct contacts and (ii) local reduction of occupant's vibration level in vehicles involves lesser difficulty and energy consumption, when compared to the strategy of controlling the level of vibration globally, in such vehicles.…”

An Energy Saving Variable Damping Seat Suspension System With Regeneration Capability

“…A negative stiffness seat suspension is proposed for a passive seat suspension to have better performance in resonance frequency [2]. The active seat suspensions has been proposed with different actuators, such as the electromagnetic linear actuator [3], the hydraulic absorber [4], the pneumatic actuator [5] and the rotary motor [6][7][8]. The active seat suspension has best performance in improving ride comfort, but the high energy consumption is the main issue for its application.…”

Dynamics of a group of quasi-zero stiffness vibration isolators with slightly different parameters

“…21 Systems with quasi-zero stiffness can be also obtained by active or semi-active methods. Seat suspensions with semi-active devices are proposed by Choi et al 22,23 Electromagnetic linear actuators are used by Gan et al 24 and electric servomotor with a ball screw mechanism as the active seat suspension actuator is used by Kawana and Shimogo. 25 Electromagnetic systems are presented by Robertson et al 26 Unfortunately, active systems with quasizero stiffness are usually rather expensive.…”