No abstract

This paper presents the design, fabrication and testing of an innovative active seat suspension system for heavy-duty vehicles. Rather than using conventional linear actuators, such as hydraulic cylinders or linear motors, which need to be well maintained and are always expensive when high force outputs are required, the proposed seat suspension system directly applies a rotary motor in order to provide the required active actuation, without changing the basic structure of the existing off-the-shelf seat suspension. A gear reducer is also applied to amplify the output torque of the motor so that a high output torque can be achieved using a low rated power motor. A static output feedback H 1 controller with friction compensation is designed to actively reduce seat vibration. Experiments are carried out to test the fabricated suspension prototype. The experimental results show that this type of seat suspension can achieve greater ride comfort in the frequency range of 2-6 Hz than a passive seat suspension. The newly designed active seat suspension is much more cost effective and can be suitable for heavy-duty vehicles.

A seat suspension with a rotary magnetorheological damper for heavy duty vehicles AbstractThis paper presents the development of an innovative seat suspension working with a rotary magnetorheological (MR) fluid damper. Compared with a conventional linear MR damper, the well-designed rotary MR damper possesses several advantages such as usage reduction of magnetorheological fluid, low sealing requirements and lower costs. This research starts with the introduction of the seat suspension structure and the damper design, followed by the property test of the seat suspension using an MTS machine. The field-dependent property, amplitudedependent performance, and the frequency-dependent performance of the new seat suspension are measured and evaluated. This research puts emphasis on the evaluation of the vibration reduction capability of the rotary MR damper by using both simulation and experimental methods.

No abstract

No 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 variable resonance magnetorheological-fluid-based pendulum tuned mass A variable resonance magnetorheological-fluid-based pendulum tuned mass damper for seismic vibration suppression damper for seismic vibration suppression

No abstract