Aiming to develop a practical active suspension, a PMSM ball screw actuator prototype is manufactured and experimented for parameter identification. Based on identification results, a new double-vibration-reduction-structure for the featured active suspension is proposed to cope with the problem caused by the actuator’s overlarge equivalent inertial mass. Unlike using a resistance to absorb output energy of the actuator, a method of varying charge voltage in steps is utilized to reclaim vibration energy into the battery pack directly. The mechanical and energy-regenerative characteristics are tested for verification of the marked parameters and identification of the unmarked parameters, especially for the Coulomb damping and the equivalent inertial mass of the actuator prototype. Besides, a high energy-regenerative efficiency and a large capability of electromagnetic control force are achieved, the overlarge equivalent inertial mass exists. To reduce the amplified demand of the active control force caused by the actuator’s overlarge equivalent inertial mass directly exposed to the unsprung mass acceleration, the new double-vibration-reduction-structure (DVRS) based active suspension structure scheme suggestion with an added-vibration-reduction-structure (AVRS) between the actuator and the unsprung mass is proposed. Regulated by the corresponding LQG controller, the proposed active suspension can achieve almost the same performance of the conventional ideal active suspension.

The electromagnetic-mechanical wedge brake system (EMWB) is a new structure designed for brake-by-wire system. This structure is composed of a DC motor, an electromagnet device, two wedges, two friction plates, a rotating rod and a brake disk. The presented EMWB system contains two brake actuators such as electromagnetic brake and motor brake. The EMWB system provides a mechanical backup brake model driven by the DC motor when the electromagnetic brake fails. In the braking relief phase, the maximum torque of the DC motor should meet the requirement of separating the friction plates from the brake disk, so the brake performance of EMWB system is simulated with Matlab/Simulink and optimized under the multi-objective constraints, and the simulation results demonstrate that the mechanical backup brake model can meet the brake requirements both for the front axle and the rear axle. Through the multi-objective optimization, the EMWB system can reach an acceptable brake performance and the DC motor can meet the requirement of relieving braking.

A common bushing is suggested to be upgraded into a bushing spring by thickening the rubber layer to pragmatize the dual vibration reduction structured (DVRS) active suspension. To remedy negative influence of the actuator equivalent inertial mass on the vertical vibration performance of the active suspension utilizing the rotary-motor actuator, a DVRS active suspension scheme via bushing spring is proposed and its corresponding nonlinear controller is specially developed. The “quasi-saturation” damping force and “inverse S-shaped” elastic force model is proposed to match the bushing spring test data. The corresponding nonlinear parameter visual optimization based H $_2$ /H $_∞$ controller is specially developed to deal with the nonlinear factors of the DVRS active suspension and the absence of linear damping of the bushing spring. Simulation and hardware-in the-loop experimental results corroborate the effectiveness of the featured DVRS active suspension regulated by the specially designed controller with good performances under both D-class and bumpy road running conditions, especially in reducing the body acceleration and improving vehicle ride comfort.

To design an effective intelligent control algorithm for performance improvement of the MR semi-active suspension for intelligent vehicles, there is a demand to considerably shorten and precisely model the MR damper response time. A rapid response current source is developed to shorten the output current response time, and the corresponding experimental method is proposed to provide measurement data to accurately model both the MR damper's rising and descending response times. Firstly, a unilateral series pre-charged capacitor based current source and the corresponding receding design method are presented. Subsequently, the experimental scheme is designed to test the MR damper's rising and descending response times under both different exciting sine displacement frequencies and square-waved control current amplitudes. Consequently, both the MR damper's rising and descending response times are precisely modeled. Analyses of experimental results corroborate effectiveness of the self-manufactured rapid response current source and precision of the testing data based models for the MR damper's rising and descending response times. Especially by adopting the newly developed current source, when both the exciting displacement frequency and control current change, the MR damper's rising and descending response times are reduced to less than 9 ms subjected to the control current amplitude of 3 A, and the maximum model error is less than 2%.

Accurate road irregularity model is very important to ensure reliability of vehicle dynamics simulation. Besides that modeling accuracy of power spectral density (PSD) around the lower cut-off frequency (LCOF) is poor, the method real-time generating non-stationary two wheel road irregularities still absents. To solve the above problems, a novel superposition of high-order filtering (HOF) white noises modulated by coherent and incoherent functions based reconstruction method is presented. The HOF white noise model is responsible for modeling accuracy of PSD related to the LCOF and different road irregularity's frequency exponents. The HOF, coherent and incoherent transfer functions are newly developed to modulate three independent standard white noises to generate non-stationary road irregularities online. Three reconstruction applications verify that the PSD and coherent function curves of the reconstructed road irregularities agree with those of the actual ones well respectively.