Ruochen Wang

Design and experiment study of a semi-active energy-regenerative suspension system

A new kind of semi-active energy-regenerative suspension system is proposed to recover suspension vibration energy, as well as to reduce the suspension cost and demands for the motor-rated capacity. The system consists of an energy-regenerative damper and a DC-DC converter-based energy-regenerative circuit. The energy-regenerative damper is composed of an electromagnetic linear motor and an adjustable shock absorber with three regulating levels. The linear motor just works as the generator to harvest the suspension vibration energy. The circuit can be used to improve the systems energy-regenerative performance and to continuously regulate the motors electromagnetic damping force. Therefore, although the motor works as a generator and damps the isolation without an external power source, the motor damping force is controllable. The damping characteristics of the system are studied based on a two degrees of freedom vehicle vibration model. By further analyzing the circuit operation characteristics under different working modes, the double-loop controller is designed to track the desired damping force. The external-loop is a fuzzy controller that offers the desired equivalent damping. The inner-loop controller, on one hand, is used to generate the pulse number and the frequency to control the angle and the rotational speed of the step motor; on the other hand, the inner-loop is used to offer the duty cycle of the energy-regenerative circuit. Simulations and experiments are conducted to validate such a new suspension system. The results show that the semi-active energy-regenerative suspension can improve vehicle ride comfort with the controllable damping characteristics of the linear motor. Meanwhile, it also ensures energy regeneration.

Study on coordinated control of the energy regeneration and the vibration isolation in a hybrid electromagnetic suspension

A type of hybrid electromagnetic suspension is proposed in this study to improve the reliability of a conventional active electromagnetic suspension. A motor with the proposed hybrid electromagnetic suspension linear can regenerate the vibration energy; the coordination relationship between the energy regeneration and the vibration isolation of the hybrid electromagnetic suspension is studied. A dynamic model is established, and a modified skyhook control strategy is designed. A passive energy regeneration control system and an active control system are developed. The effect of the damping on the energy regeneration and the vibration isolation is discussed. The best damping, which can consider the energy regeneration and the vibration isolation simultaneously, is determined. Comparative simulations of a passive suspension, a hybrid electromagnetic suspension and an active electromagnetic suspension are carried out, and the results verify the effectiveness of the control strategy. Finally, an energy regeneration experiment and an isolation comparative experiment of a quarter-suspension are conducted. The findings show that the hybrid electromagnetic suspension with a modified skyhook control strategy can efficiently facilitate coordination between the energy regeneration and the vibration isolation.

Energy Conservation Analysis and Control of Hybrid Active Semiactive Suspension with Three Regulating Damping Levels

Active suspension has not been popularized for high energy consumption. To address this issue, this paper introduces the concept of a new kind of suspension. The linear motor is considered to be integrated into an adjustable shock absorber to form the hybrid active semiactive suspension (HASAS). To realize the superiority of HASAS, its energy consumption and regeneration mechanisms are revealed. And the system controller which is composed of linear quadratic regulator (LQR) controller, mode decision and switch controller, and the sliding mode control based thrust controller is developed. LQR controller is designed to maintain the suspension control objectives, while mode decision and switch controller decides the optimal damping level to tune motor thrust. The thrust controller ensures motor thrust tracking. An adjustable shock absorber with three regulating levels to be used in HASAS is trial produced and tested to obtain its working characteristics. Finally, simulation analysis is made with the experimental three damping characteristics. The impacts of adjustable damping on the motor force and energy consumption are investigated. Simulation results demonstrate the advantages of HASAS in energy conservation with various suspension control objectives. Even self-powered active control and energy regenerated to the power source can be realized.

Design and test of vehicle suspension system with inerters

A vehicle suspension system with inerters is proposed and its dynamic model is established to analyse its dynamic performance. The structure of the suspension with inerters is also constructed and its form and structural parameters are optimized. Then the rack-and-pinion inerter and the bench test system of suspension are designed. Based on the simulation, bench test is conducted. It has shown that theoretical research is consistent with the test results. Moreover, the structure of the suspension with inerters is so simple, that it can be easily achieved. Consequently the passenger comfort is greatly enhanced and the comprehensive performance of the car has been coordinated. Therefore, simulated analysis and experimental tests in this paper can provide evidence for further research on suspension with inerters.

Energy-saving control strategy design and structure realization for electromagnetic active suspension

An electromagnetic active suspension equipped with a linear motor can remarkably improve the dynamic performance of a vehicle in terms of ride comfort and handling stability. However, electromagnetic active suspensions consume a considerable amount of external energy. Therefore, an energy-saving control strategy and its corresponding realization structure are designed to reconcile the contradiction between the dynamic performance and energy consumption. The energy conservation feasibility of an electromagnetic active suspension system is investigated in this study. Subsequently, the conventional skyhook control strategy is used as a reference; a passive damping is introduced to improve the defects of the system for an active control. It can also ensure the basic dynamic performance during energy regeneration. The energy-saving control strategy is placed beside the switch between the active control and energy regeneration. The vehicle simulation manifests that the energy-saving control strategy can effectively inhibit body movement, including vibration, roll, and pitch, while exhibiting a good road holding. A single linear motor used for the suspension system deteriorates the dynamic performance during energy regeneration and cannot guarantee the system reliability because of its low passive damping. Thus, a new integrated electromagnetic actuator prototype is developed, and the bench test shows that the prototype can satisfy the control requirements of the energy-saving control strategy.