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Conventional viscous shock absorbers, in parallel with suspension springs, passively dissipate the excitation energy from road irregularity into heat waste, to reduce the transferred vibration which causes the discomfort of passengers. Energy-harvesting shock absorbers, which have the potential of conversion of kinetic energy into electric power, have been proposed as semi-active suspension to achieve better balance between the energy consumption and suspension performance. Because of the high energy density of the rotary shock absorber, a rotational energy-harvesting shock absorber with mechanical motion rectifier (MMR) is used in this paper. This paper presents the assessment of vehicle dynamic performance with the proposed energy-harvesting shock absorber in braking process. Moreover, a PI controller is proposed to attenuate the negative effect due to the pitch motion.

Lane-changing systems have been developed and applied to improve environmental adaptability of advanced driver assistant system (ADAS) and driver comfort. Lane-changing control consists of three steps: decision making, trajectory planning and trajectory tracking. Current methods are not perfect due to weaknesses such as high computation cost, low robustness to uncertainties, etc. In this paper, a novel lane changing control method is proposed, where lane-changing behavior is analogized to parallel parking behavior. In the perspective of host vehicle with lane-changing intention, the space between vehicles in the target adjacent lane can be regarded as dynamic parking space. A decision making and path planning algorithm of parallel parking is adapted to deal with lane change condition. The adopted algorithm based on rules checks lane-changing feasibility and generates desired path in the moving reference system at the same speed of vehicles in target lane.

A hydraulic chamber is embedded in serial with the accumulator of a normal mono-tube magnetorheological fluid damper (MRFD). The damper stiffness can be adjusted by changing the accumulator volume with the hydraulic chamber. The hydraulic chamber is connected to an electric pump and controlled by the braking-by-wire (BBW) system. A modified bi-viscosity magnetorheological fluid (MRF) model that explicitly includes the parameter of control current is proposed. A dynamic model of this hydraulic MRFD is subsequently set up based on the MRF model. Experiments are conducted to validate the model and simulations are carried out to study the influences of accumulator volume on the external performances. Results show that the hydraulic chamber is able to provide rapid variations of the external force through accumulator volume changes.

Although energy harvesting systems are extensively used in different fields, studies on the application of energy harvesters embedded in tires for vehicle control are rare and mostly focus on solving power supply problems of tire pressure sensors. Sensors are traditionally powered by an embedded battery, which must be replaced periodically because of its limited energy storage. Heightened interest in vehicle safety is expected to drive increased design and manufacture of in-tire sensors, which in turn, translates to rising demand for power generation in tires. These challenges emphasize the need to investigate the substitution of batteries and in-tire energy harvesting systems. Current in-tire energy harvesting methods involve piezoelectric, electromagnetic, and electrostatic power generation, whose energy sources include tire vibrations, deformations, and rotations. Piezoelectric harvesters are generally compact but operate for short durations.

A tire force estimation algorithm is proposed for vehicle dynamic stability control (DSC) system to protect the vehicle from deviation of the normal dynamics attitude and to realize the improved dynamics stability in limited driving conditions. The developed algorithm is based on the theoretical analysis of all the subsystems of the active brake control in DSC system and modulation in DSC, and the robustness is achieved by a compensation method using nonlinear filter in the real time control. The software-in-loop simulation using Matlab/AMEsim and the ground test in the real car show the validation of this method.

Based on the study of the dynamic characteristics, the observers for tire force, lateral and longitudinal velocity, and vehicle stability matrix are proposed. The stability matrix is used to predict the stability of the vehicle involving the vehicle dynamic constraints and the active brake pressure modulator. Integrating the proposed method into the state feedback control logic, the predictive control algorithm is brought forward. The simulation results show that the over shoot is restrained and the oscillatory of the steering handling character is overcome.

The traditional vacuum booster is gradually replaced by Brake-by-Wire system (BBW) in modern passenger car, especially Electric Vehicle (EV). Some mechanical and hydraulic components are replaced by electronic components in Brake-by-Wire system. Using BBW system in modern passenger vehicles can not only improve the automotive safety performance, reliability and stability, but also promote vehicle maneuverability, comfort, fuel economy and environmental protection. Although vehicle's braking performance is greatly improved by using BBW, the system will inevitably consume some energy of the vehicle power supply, thus introducing unexpected drawback in comparison with the traditional vacuum assist braking system, since it doesn't need any electric power. Therefore, the analysis of energy consumption on typical main cylinder booster based BBW system under typical driving cycles will contribute to advanced design of current advanced braking system.

Electro-hydraulic power steering system (EHPS) uses the motor as the power source instead of the engine to assist drivers to steer. Compared with traditional hydraulic power steering system (HPS), EHPS system has a better performance in energy saving and driving feeling. In EHPS system, the speed control of the motor determines the performance of the whole system. In this paper, a speed control system of brushless direct current (BLDC) motor based on a Fuzzy-PI controller is established. In addition to the function to adjust speed by adjusting voltage, field weakening is utilized to get a wider speed range, so that the EHPS system has a better performance.

Prototype of a brake-by-wire (BBW) system named Distributed Electro-hydraulic Braking System (DEHB) has been developed. As a BBW system, DEHB is suitable to be used in electric vehicles (EV) and hybrid electric vehicles (HEV). Comparing to the ‘dry’ type distributed BBW systems such as Electro-mechanical Braking System (EMB) or Electric Wedge Brake (EWB), the ‘wet’ feature of DEHB brings benefits to system cost, installation, performance and reliability. In this paper, prototype of the DEHB was described. Based on its ‘wet’ feature, a new fail-safe control for DEHB was proposed. Two types of DEHB architectures that can perform the proposed fail-safe control were described. Superiority of the proposed fail-safe control and architectures for DEHB were examined and verified through simulations and HIL experiments, which helps DEHB to reach a high level of safety and reliability with reduced cost on electro/electronic redundancy.

This paper proposed a collision avoidance strategy that take over the control of ego vehicle when faced with urgent collision risk. To improve the applicability of collision avoidance strategy in complex scenarios, the theory of ICS (Inevitable Collision State) is introduced to evaluate the collision risk and compute the trigger flag of the system, and vehicle dynamic is taken into account when modeling ego vehicle to predict ego vehicle’s following moving. Vehicle specific characteristics including reaction time of the braking system and the braking force increasing process are taken into account. In order to reduce injury caused by collision accidents and minimize disruption to drivers, slight steering is added on top of emergency braking. The direction of the steering angle is determined according to IM (Imitating Maneuvers) The flow chart of the strategy is presented in the paper.

Hydraulic retarder is important auxiliary brake device which widely used in commercial vehicles for its economy, safety and driving comfort, however cavitation will occur and reduce the braking performance when hydraulic retarder operates at high speed. In this paper, a model of hydraulic retarder considering cavitation effect was established, and the reliability of the model was verified by comparing with the external characteristics of the product which was obtained from Voith’s official discloses data. Then the cavitation of hydraulic retarder under high-speed working condition was studied by the establishing simulation model. The simulation model can describe and analyze the internal flow field in the hydraulic retarder, and can be used as an important tool for the development and optimization of hydraulic retarder in the future. When hydraulic retarder’s rotational speed is about 1500rpm, the cavitation will be observed in the working chamber.

The paper presents a new electromechanical brake system for vehicles using magnetorheological fluid. The brake system designed for the electric vehicle has some advantages over the conventional brake system. The brake system is made up of a brake disk, shells, magnetorheological fluid (MRF) and the electromagnets. The brake disk is immersed in the MRF whose yield stress changes as the applied magnetic field. The braking torque of this system can be linearly adjusted by the current in just a few milliseconds without the conventional vacuum booster. This system has a quick response and precise control performance with a low hysteresis. Besides, the system has adopted the original complicated structure to save space and cost. In this paper, the configuration of MRF brake types is described. The braking torques of the MRF brakes is derived based on the MRF theoretical model which is firstly raised. Some braking simulation based on the theoretical model is also shown.

With the development of intelligent vehicle and active vehicle safety systems, the demand of sensors is increasing, especially in-tire sensors. Tire parameters are essential for vehicle dynamic control, including tire pressure, tire temperature, slip angle, longitudinal force, etc.. The diversification and growth of in-tire sensors require adequate power supply. Traditionally, embedded batteries are used to power sensors in tire, however, they must be replaced periodically because of the limited energy storage. The power limitation of the batteries would reduce the real-time data transmission frequency and deteriorate the vehicle safety. Heightened interest focuses on generating power through energy harvesting systems in replace of the batteries. Current in-tire energy harvesting devices include piezoelectric, electromagnetic, electrostatic and electromechanical mechanism, whose energy sources include tire deformations, vibrations and rotations.

An identification method using recursive least-squares method with moving data window and reduced-order disturbance observer iteratively is proposed in this paper to identify fast time-varying braking force in the electronic mechanical braking system (EMB). For the type of EMB which generates braking force by balls screw and motor mounted beside wheel, the actuator will go rapidly to eliminate clearance at beginning of braking process by means of raising the braking response speed, and at the same time, increasing the motor output torque which might be far larger than required. The proposed identification method is able to identify the point of contact between the brake pads and the disk in time by identifying the change of break force, and the torque of motor will be changed in time to reduce the braking force overshoot so that brake locking is avoided.

With the advantages of free from engine vacuum, wheel cylinder pressure decoupled from the brake pedal and can be regulated individually and precisely, the brake-by-wire system has a huge application potential in vehicles, especially in electric vehicles (EV) and hybrid electric vehicles (HEV). Electro-hydraulic Brake system is the first approach towards brake-by-wire technology. This paper proposed a new compact EHB, aiming at decreasing the size, volume and cost without compromise of performance. The main components of the proposed EHB are pedal simulator, motor pump, accumulator and eight solenoid valves. An authentic model of the EHB and other key components of the brake system were established based on the test data from the test bench. A control algorithm using Round-Robin scheduling was presented to regulate the fluid pressure. Some parameters of the components were discussed to research their effects on system performance.

The paper is focused on the research of the automotive magneto-rheological brake system whose braking force comes from the shear stress of magneto-rheological fluid under the condition of magnetic field. The MRF brake is designed for an electric passenger car to replace a conventional hydraulic disc-type brake. The braking torque of this system can be linearly adjusted by the current in just a few milliseconds with proper materials. Therefore this system has a quick response and precise control performance with a low hysteresis. Nowadays, most of the related research of MRF is about the construction of the prototype and the realization of the brake force. Main limitation of MRF brake lies in the braking torque cannot meet the actual needs and the power consumption may be too much if it is not well designed. The prototype introduced in the SAE Brake Colloquium-31nd Annual has been manufactured and assembled critically.

Many types of brake by wire systems have been developed in past years, such as EMB (Electro-mechanical Brake) [1, 2], DEHB (Distributed Electro-hydraulic Braking System) [3] and EWB (Electric Wedge Brake) [4]. When the vehicle need braking in long period such as waiting for traffic light or downhill braking in those brake systems, the current will sustain very long time with very high level. This current will result in high temperature in motor, and will damage the power supplier. When a new DEHB is developing, a holding function is added in this DEHB. The holding function is self-energized when holding the brake, and automatic released after the brake. Advantageously, after activation of the holding function, the current delivered to the motor for braking is substantially decreased, especially, will be zero when the brake torque is not need to adjust.

This paper presents a new magnetorheological braking which can be used in vehicles. Magneto-rheological (MR) fluid is a novel material which can be used in different components of vehicle. Magneto-rheological fluids (MRF) are suspensions of micron size whose yield stress varies rapidly as the change of magnetic field. The use of MRF in vehicles has been gaining popular recently due to its strong rheological effect, fast response and low energy consumption. Besides, these performances give designers more choice in automotive designs. However, most of the related research of MRF brake is about the construction of small prototype to verify its rheological performance. As a result, research progress is limited to calculation and simulation which make the braking force of prototype can hardly meet the requirement of vehicle due to a lack of optimal design and the understanding of MRF in the situation of high sheer stress and magnetic field.

In a monotube magnetorheological fluid damper (MRFD), there usually exists a compensation chamber with designated initial gas pressure. This enclosed compensation chamber works as an air spring to some degree to provide force to the working piston. In this work, in order to extend the external damping force range and improve the controlling efficiency, a structure of MRFD with three additional accumulators is proposed. These additional accumulators are connected to the atmosphere through an air pump and the compensation chamber with a barometric valve. The external damping force range thus can be rapidly adjusted through mode shifting with this configuration. A mathematical model of this damper with coupled effects between the air and the magnetorheological fluid (MRF) is developed. Comparing the bench tests results with some simulation outcomes, the simulation model of this MRFD is validated.

Special purpose flat-bed vehicle is commonly utilized to move heavily items such as containers in warehouse, port and other freight handling scene, the hydraulic steering system have be gradually replaced by electric ones. However, the cost of electric steering system is high for commercial activities. Thus, for some corporates, the differential braking steering strategy becomes an ideal alternative. The purpose of this paper is to present a steering control method for flat-bed electric vehicle based on differential braking system. There are two main components of the control method, steering while moving forward and pivot steering, and each of them was composed by upper layer and executive layer. To evaluate the practicability of the control methods, a 7-DOF flat-bed vehicle model was established in Simulink.