Disturbance observer based Takagi-Sugeno fuzzy control for an active seat suspension

Abstract

In this paper, a disturbance observer based Takagi-Sugeno (TS) fuzzy controller is proposed for an active seat suspension, and this controller is validated by both simulations and experiments. The proposed controller applies the seat acceleration and seat suspension deflection which can be easily measured in practical application as feedbacks. A disturbance observer that can estimate disturbance caused by friction force, model simplification, and control output error is used to compensate a ∞ state feedback controller. The TS fuzzy control method is applied to enhance the controller's performance by considering the variation of driver's weight. Because the vertical vibration of heavy duty vehicle seat is highest in the frequency range 2 Hz to 4 Hz, it is reasonable to focus on controlling low frequency vibration and maintain seat suspension's passivity at high frequency (isolating vibration) to release the requirement to the actuator. The simulation and experimental results show that the active seat suspension with the proposed controller can effectively isolate vibration under 4.5 Hz when compared with a well-tuned passive seat suspension. The active controller is further validated under bump and random road tests with 55 Kg and 70 Kg loads, respectively. The bump road test shows the controller has good transient response capability. The random road test result is presented both in time domain and frequency domain. The controlled seat suspension root-mean-square (RMS) acceleration is reduced by 45.5% and 49.5%, respectively, when compared with a well-tuned passive seat suspension. The proposed active seat suspension controller is very practical for application and can greatly improve heavy duty driver's ride comfort.

A Systematic Literature Review of Various Control Techniques for Active Seat Suspension Systems

“…Takagi-Sugeno fuzzy control based on a disturbance observer was applied to improve the ride comfort of the driver [45]. Disturbance observer was used to estimate all possible disturbances caused by model simplification, friction force and actuator saturation.…”

A Review of Low-Frequency Active Vibration Control of Seat Suspension Systems

“…A new active seating vibration reduction structure ( Figure 12) was proposed in [57][58][59][60]. This seating system is based on the common scissor-like structure of commercial vehicle seating systems, using an inexpensive conventional rotary electric motor instead of an expensive linear motor as the actuator.…”

“…A second layer was added to the preceding scissor-like structure to control the vibration of pitching and rocking. The second layer consists of a universal joint and four support With the same active seat suspension system, a disturbance observer based on the Takagi-Sugeno (TS) fuzzy controller was proposed by [60] for active seat suspension vibration control ( Figure 14). The controller used a closed-loop feedback control with acceleration and seat suspension displacement measurement signals to achieve good adaptability and robustness.…”

“…However, due to the difficulty of measuring actual human body properties and because an accurate biodynamic model may dramatically increase the amount of computation time, a simplified model has been used as a common method in research. In [59,60], the human body was replaced by a mass, and the amount of calculation time was reduced by ignoring the complex dynamic behavior of the human body itself. The ANN controllers mentioned here are summarized in Table 3.…”

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.…”