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The suspension system plays a crucial role in mitigating vehicle vibration, enhancing passenger comfort, and improving driving handling stability. While many mechanical experimental platforms exist for testing suspension system performance, they often need high costs and precision requirements. In the field of modern industrial product design, hardware-in-the-loop (HIL) simulation has become an invaluable tool. Electrically interconnected suspension (EIS) is a novel type of interconnected suspension by connecting various suspensions in an electrical way. The novel EIS avoids many drawbacks of traditional interconnected suspensions. The EIS is usually composed of electromagnetic motors and electrical networks (EN). By designing the structure of the EN reasonably, the EIS system can achieve decoupling control in multiple vibration modes. This paper introduces an HIL experimental platform established for a half-car EIS system based on an NI Compact RIO 9049.

The powertrain system plays a crucial role in electric vehicles, exerting significant impact on both the dynamic and economic performances. A breakthrough has been observed by using the dual-motor powertrain system, which outperformed its single-motor counterparts. This study reports a dual-motor powertrain with magnetorheological technology. The powertrain consists of two motors, two magnetorheological brakes and a planetary gear set. Via regulating the brakes, the power transmission flow can be controlled to realise different torque ratios and velocities. The synergetic control of motors and brakes is capable of achieving smooth gear shifting without interruption. This paper details the design of the powertrain system: the structural configuration of the magnetorheological brakes is highlighted, the magnetic field distribution of the brakes under different currents is simulated by COMSOL Multiphysics, and the torque capacities of the brake are also calculated.

Electromagnetic damper (EMD), which has shown good vibration isolation and energy harvesting potential, has received much attention in recent years. In addition, the harvested energy of EMD systems can be used to further suppress severe vibration. When the harvested energy of the suspension system is more than the consumed energy, the suspension system can realize self-powered functions. However, the integration of the above three functions is a challenge for the design of EMD systems. In this paper, a novel multi-function electromagnetic damper (MFEMD) system, which integrates the semi-active vibration control mode, energy-harvesting mode, and self-powered mode, is introduced first. The MFEIS system applies an H-bridge circuit to control the multi-directional flow of circuit energy flow, and the supercapacitor is used as the energy storage device because of its high-power density and rapid response speed.

In order to further improve the influence of the electrically interconnected suspension (EIS) on the ride-comfort, a four-port electrical network (EN) is established in the SIMULINK environment based on the existing EIS research and applied to the passive model of the cabin system. This model is a passive suspension model composed of the road surface excitation, the main suspension, and the cabin suspension. The electrical network of EIS is connected with the cabin suspension section so that the interconnection is completely achieved in the cabin suspension system. The simulation results indicated that the four-port EIS is able to decouple the cabin motion in the three directions of heave, pitch, and roll, and improved the ride comfort and handling stability by adjusting the parameters of the circuit components.

Recently, a lot of electric vehicle (EV) has been developed to improve the energy consumption problem and electric power steering system has attracted the researchers’ concern. Steer-by-Wire (SbW) system is an electric steering system where the mechanical link between the steering wheel and front wheels is eliminated. Due to the absence of direct mechanical linkage, the most challenging issue is to ensure that the front wheels closely follow the driver’s command. A sliding mode predictive controller (SMPC) for Steer-by-Wire systems (SbW) is proposed to achieve a proper tracking performance. The sliding mode predictive controller has two parts: sliding mode control (SMC) and model predictive control (MPC). The SMC is applied to improve the robustness of MPC in the presence of model uncertainties while the MPC is applied to enhance the tracking performance of SMC.

Active suspension control for in-wheel switched reluctance motor (SRM) driven electric vehicle with dynamic vibration absorber (DVA) based on robust H∞ control method is presented. The mounting of the electric drives on the wheels, known as in-wheel motor (IWM), results in an increase in the unsprung mass of the vehicle and a significant drop in the suspension ride performance and road holding stability. Structures with suspended shaftless direct drive motors have the potential to improve the road holding capability and ride performance. The quarter car active suspension model equipped with in-wheel SRM is established, in which the SRM stator serves as a dynamic vibration absorber. The in-wheel SRM is modelled using an analytical Fourier fitting method. The SRM airgap eccentricity is influenced by the road excitation and becomes time-varying such that a residual unbalanced radial force is induced. This is one of the major causes of SRM vibration.

This paper proposes a new braking torque distribution strategy for electric vehicles equipped with a hybrid hydraulic braking and regenerative braking system. The braking torque distribution strategy is proposed based on the required braking torque and the regenerative braking system’s status. To get the required braking torque, a new strategy is designed based on the road conditions and driver's braking intentions. Through the estimated road surface, a robust wheel slip controller is designed to calculate the overall maximum braking torque required for the anti-lock braking system (ABS) under this road condition. Driver's braking intentions are classified as the emergency braking and the normal braking. In the case of emergency braking, the required braking torque is to be equal to the overall maximum braking torque. In the case of normal braking, the command braking torque is proportional to the pedal stroke.

Development of a passive anti-pitch anti-roll hydraulically interconnected suspension (AAHIS) with the advantage of improving vehicle directional stability and handling quality is presented. A 7 degrees-of-freedom full car model and a 20 degrees-of-freedom anti-pitch anti-roll hydraulically interconnected suspension model dynamically coupled together through boundary conditions are developed and used to evaluate vehicle handing dynamic responses under steering/braking maneuvers. The modeling of mechanical subsystem is established based on the Newton’s second law and the fluid subsystem is modelled using a nonlinear finite-element approach. A motion-mode energy method (MEM) based on the calculation of the motion-mode energy is employed to investigate the effects of an anti-pitch anti-roll hydraulically interconnected suspension (AAHIS) system on vehicle body-wheel motion-mode energy distribution.

This paper presents a study on experimental vibration simulation using a multiple-DOF motion platform for heavy duty vehicle seat suspension test. The platform is designed to have 6-DOF with the advantages of high force-to-weight ratio, high dexterity and high position accuracy. It can simulate vehicle vibrations in the x, y and z translational axis and in the roll pitch and yaw axis rotation. To use this platform to emulate the real vibration measured from vehicle seat base under real operation for vehicle seat suspension test in lab, an Inertial Measurement Unit (IMU) is applied to collect the acceleration data from a real vehicle. An estimation algorithm is developed to estimate the displacement from the measured acceleration. The estimated displacement is then used to calculate the length of each leg of the platform so that the platform can generate the motion similar to the measured one.

In this paper, a more sophisticated mathematical linear model for a roll-plane active hydraulically interconnected suspension (HIS) system was developed. Model parameters tuning were then carried out, which resulted in a model that is capable of producing rather accurate estimation of the system, with significant improvements over models built previously. For the verification of the new model, two simulations and corresponding experiments are conducted. Data comparisons between the simulations and experiments show high consistent responses of the model and the real system, which validated the robustness and accuracy of the new mathematical model. In this process, the characteristics of the pressure response and the rise time inside the actuators have been revealed due to the presence of the flow.

The omni-directional vehicle is an innovative vehicle, in which the in-wheel steering motor and in-wheel driving motor are integrated into each wheel of the vehicle so that each wheel can be independently controlled to have traction, braking, and turning motions to improve the vehicle's mobility, handling and stability. To realize good performance, various control strategies have been proposed, like the active steering control and the direct yaw moment control, where the accurate slip angle information is critical to these control strategies. However, in practice, the side slip angle is hard or expensive to be measured for a passenger vehicle, therefore, different estimation methods have been proposed in the literature. In this paper, a novel side slip angle estimation method is proposed for the omni-directional vehicle that has four independent steering motors.

In order to make the active suspension more affordable, a novel low-cost active hydraulically interconnected suspension is developed, assembled and tested onto a sport utility vehicle. H∞ roll control strategy is employed to control vehicle body's roll motion. The hydraulic suspension model used for deriving the H∞ controller is estimated experimentally from the testing data. The active suspension model is then combined with the half-car model through their mechanical-hydraulic interface in the cylinders. The weighting function design of the H∞ control is provided. On a 4-post-test rig, the active suspension with H∞ control is validated with several road excitations. The test rig and experimental setup are explained and the obtained results are compared. The effectiveness of the designed H∞ controller is verified by the test data, with a considerable roll angle reduction in the three tests presented.

Mainly motivated by developing cost-effective vehicle anti-roll systems, hydraulically interconnected suspension has been studied in the past decade to replace anti-roll bars. It has been proved theoretically and practically that hydraulic suspensions have superior anti-roll ability over anti-roll bars, and therefore they have achieved commercial success in racing cars and luxury sports utility vehicles (SUVs). However, since vehicle is a highly coupled complex system, it is necessary to investigate/evaluate the hydraulic-suspension-fitted-vehicle's dynamic performance in other aspects, apart from anti-roll ability, such as ride comfort, lateral stability, etc. This paper presents an experimental investigation of a SUV fitted with a hydraulically interconnected suspension under a severe steady steering maneuver; the result is compared with a same type vehicle fitted with anti-roll bars.

This paper presents a robust controller design method for improving vehicle lateral stability and handling performance. In particular, the practical load variation will be taken into account in the controller synthesis process such that the controller can keep the vehicle lateral stability and handling performance regardless of the load variation. Based on a two-degree-of-freedom (2-DOF) lateral dynamics model, a model-based Takagi-Sugeno fuzzy control strategy is applied to design such a controller and the sufficient conditions for designing such a controller are given in terms of linear matrix inequalities (LMIs) which can be solved efficiently using currently available numerical software. Numerical simulations are used to validate the effectiveness of the proposed control approach.

A robust controller design method for vehicle roll control with variable speed and actuator delay is presented. Based on a three-degree-of-freedom (3DOF) yaw-roll model, the H∞ performance from the steering input to the vehicle body roll angle is considered. The design approach is formulated in terms of the feasibility of delay-dependent matrix inequalities. By combining the random search of genetic algorithms (GAs) and the efficient solution of linear matrix inequalities (LMIs), the state feedback controllers can be obtained. The approach is validated by simulations showing that the designed controllers can achieve good performance in roll control.