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At present, the active safety and stability of heavy vehicles have becoming big concern among the road transportation industry. The purpose of this paper is to specify the research stability and safety of heavy vehicles those set up the accurate and reliable dynamic vehicle reference model and search the method to improve the stability and safety of tractor and semitrailer. A Multi-objective control algorithm was studied to differential braking based on linear quadratic regulator (LQR) control method. Simulation results show that the multi-objective control algorithm can effectively improve the vehicle driving stability and safety.

The active safety and stability of tractor and trailer (heavy-duty vehicle) have becoming big concern among the road transportation industry. The purpose of this paper is to specify the research differential braking force distribution control algorithm to improve braking safety of heavy-duty vehicle. The ideal braking force of each wheel axle should be proportional to vertical load of vehicle that is also related to the road adhesion coefficient, the load and the braking intensity. Reasonable braking force distribution can enhance its braking stability and shorten the braking distance by making full use of the road adhesion condition of each wheel. A braking force distribution algorithm is proposed, in which the objective braking force change with the axle load of vehicle.

Electro-Hydraulic Brake (EHB) system is a kind of active control brake systems of automobile, the pedal from the calipers actuation separated and no longer limited by conventional hardware. The system may come together with ABS, ESP, and ASR function, also the communication with other systems is done via the CAN network. EHB system may be classified a “stepping stone” technology to full brake-by-wire and brings huge transform for the performance of braking system. In this paper, vehicle dynamic models were established and accomplished the control strategy for vehicle stability control with EHB system which can adjust wheel and vehicle motion, improve the lateral and longitudinal vehicle stability. This result was verified by simulation which shows that the controller is effective on improving the vehicle stability.

This paper sets up a simplified dynamic model for simulating the yaw/roll stability of heavy tractor-semitrailer using Matlab/Simulink. A linear quadratic regulator (LQR) based on partial-state feedback controller is used to optimize the roll stability of the vehicle. The control objective for optimizing roll stability is to be reducing the lateral load transfer rate while keeping the suspension angle less than the maximum allowable angle. The simulation result shows that the LQR controller is effective in the active roll stability control of the heavy tractor-semitrailer.

It is difficult to obtain state variables accurately or economically while vehicle is moving, however these state variables are significant for chassis control. Although many researches have been done, a complex model always leads to a control system with poor real-time performance, while simple model cannot show the real characteristics. So, in order to estimate the value of yaw rate and side slip angle accurately and sententiously, an Extended Kalman Filter (EKF) observer is proposed, which is based on an ameliorated 2-DOF “bicycle model”. The EKF algorithm is achieved numerically and verified by the results from the real field test.

This paper presents a fault-tolerant control (FTC) method for four-wheel independently driven and steered (4WIS/4WID) electric vehicles based on a reconfigurable control allocation to increase the flexibility for vehicle control and improve the safety of vehicle after the steering actuator fails. The proposed fault tolerant control method consists of the following three parts: 1) a fault detection and diagnosis (FDD) module that monitors vehicle steering condition, detects and diagnoses actuator failures; 2) an upper controller that computes the generalized forces/moments to track the desired vehicle motion and trajectory; 3) a reconfigurable control allocator that optimally distributes the generalized forces/moments to four wheels. The FTC approach based on the reconfigurable control allocation reallocates the generalized forces/moments among healthy steering actuators and driving motors once the actuator failures is detected.

Aiming at achieving the economy and safety of downhill brake process (running downward along a long slope at a constant velocity) of commercial vehicles, an integrated control strategy of the main brake system and auxiliary brake systems is proposed. Based on Electronic Controlled Braking System (EBS), the strategy distributes braking force to each brake system and each axle according to the thermodynamic feature of them and the wear loss of each brake lining, in order to achieve economy at the premise of safety. A simulation is conducted based on MATLAB/Simulink and TruckSim. Simulation results show that the strategy proposed could control the temperature of each brake system at a rational value, and the balanced wear loss of brake linings is facilitated, thus, the safety and economy of downhill brake is ensured.

The hybrid electric city bus, which consists of the electric motor and battery, is obviously different from the traditional buses. This paper focuses on optimizing the characteristics of the automatic mechanical transmission in hybrid electric city bus and does the following studies: firstly, in order to reduce the fuel consumption, the transmission ratio and some structural parameters are optimized with CRUISE software; secondly, the volume and weight of the transmission structure is reduced and optimized by numerical optimization approach, with the limitation of the structural reliability.

A fault tolerant control (FTC) approach based on reconfigurable control allocation for four-wheel independently driven and steered (4WID/4WIS) electric vehicles against driving motor failures is proposed in order to improve vehicle safety, performance and maneuverability after the driving motor failures. The proposed fault tolerant control method consists of the following three parts: 1) a fault detection and diagnosis (FDD) module that monitors vehicle driving condition, detects and diagnoses actuator failures; 2) a motion controller that computes the generalized forces/moments to track the desired vehicle motion using model predictive control method; 3) a reconfigurable control allocator that optimally distributes the generalized forces/moments to four wheels aiming at minimizing the total tire usage. The FTC approach is based on the reconfigurable control allocation which reallocates the generalized forces/moments among healthy actuators once the actuator failures is detected.

Nowadays, the endurance mileage of electric vehicle is commonly short. For the purpose of enhancing the endurance mileage of 4WD electric vehicles, this paper proposes a new control strategy based on the generation efficiency of in-wheel motors. When the brake strength is low, the strategy defines the torque on which the motor has the highest generate efficiency as the upper limit of the braking torque of the front axle. What's more, the proportion of mechanical braking force is reduced. Because of these, the vehicle has a higher generation power. The simulation model is built up by using Matlab/Simulink and CarSim software, and the strategy is simulated under several driving cycles. The result shows that, comparing with the two traditional braking force distribution strategies, the new strategy can obviously improve the regenerative efficiency.

In order to improve the braking energy recovery, a parallel hybrid electric bus simulation model with electric braking system (EBS) was established by co-simulation platform for the TruckSim and Matlab/Simulink in this paper. EBS makes the front and rear shaft braking force arbitrarily distributed, which is more effective to improve the rate of energy recovery and the braking stability. A braking force distribution algorithm for hybrid electric bus based on EBS was designed in this paper. Under the premise to meet the driver's needs and the ECE regulations, this braking force distribution method focuses on making the braking force distribute to the drive shaft to a maximum extent, so as to obtain the maximum energy recovery rate by the utilization of the motor regenerative braking. At last, the simulation in different operating conditions was used to analyze the braking energy utilization and the braking performance based on the simulation model.

Steering-By-Wire (SBW) system has advantages of advanced vehicle control system, which has no mechanical linkage to control the steering wheel and front wheels. It is possible to control the steering wheel actuator and front wheels actuator steering independently. The goal of this paper is to use a joystick to substitute the conventional steering wheel with typical vehicle SBW system and to study a variable steering ratio design method. A 2-DOF vehicle dynamic reference model is built and focused on the vehicle steering performance of drivers control joystick. By verifying the results with a hardware-in-the-loop simulation test bench, it shows this proposed strategy can improve vehicle maneuverability and comfort.

In order to improve the braking energy recovery and ensure the braking comfort, a new type of regenerative braking coordinated control algorithm is designed in this paper. The hierarchical control theory is used to the regenerative braking control algorithm. First, the front axle braking force and rear axle braking force are distributed. Then the rear axle motor braking force and mechanical braking force are distributed. Finally, the dynamic coordinated control strategy is designed to control pneumatic braking system and motor braking system. Aimed at keeping the fluctuation of the total braking force of friction and the regenerative braking force small during braking modes switch, a coordinated controller was designed to control the pneumatic braking system to compensate the error of the motor braking force. Based on Matlab/Simulink platform, a parallel hybrid electric bus simulation model with electric braking system (EBS) was established.

Electronic braking system (EBS) of commercial vehicle is developed based on Anti-lock Braking System (ABS), for the purpose of enhancing the braking performance. Based on the previous study, this paper aims at the development and research on the control strategy of advanced electronic braking system for commercial vehicle, which mainly includes braking force distribution and multiple targets control strategy. In the study of braking force distribution control strategy, the mass of vehicle and the axle loads will be calculated dynamically and the braking force of each wheel will be distributed regarding to the axle loads. The braking intention recognition takes the brake pad wear into account when braking uncritically, so it can detect a difference in the pads between the front and the rear axles. The brake assist strategy supports the driver during emergency braking and the braking distance is shortened by the reduction of the braking system response time.

The paper focus on enhancing the braking safety and improving the braking performance of the tractor/trailer vehicle. A slip-rate-based braking force distribution algorithm is proposed for the electronic braking system of tractor/trailer combination vehicle. The algorithm controls the slip-rates of the tractor's rear wheels and the semi-trailer's wheels changing with the slip-rate of tractor's front wheels, making tractor's front wheels lock up ahead of the tractor's rear wheels and the semi-trailer's wheels. The algorithm protects the combination vehicle from jackknifing and swing, guaranteeing that the combination vehicle has better driving stability and steering capability. The algorithm can be tested by co-simulation with MATLAB/Simulink and TruckSim software both on high adhesion and low adhesion roads.

As a new braking system, EHB can significantly improve the braking performance and vehicle handling and stability. In this paper the structure of high-speed on-off valve and the valve core principle are discussed, the paper also analysis the response of the valve core under different modulation frequency, duty cycle and the change of wheel cylinder pressure. Set a proper modulation frequency to make sure that electromagnetic valve can be worked in a greater linear range.

This paper establishes a brake pedal model for braking intention identification, using the structural features of electronic braking system and selecting the proper parameters. A three-dimensional model is built that the input parameters are pedal displacement and pedal displacement change rate, and the output parameter is braking intensity. The relationship between the driver braking operation and braking intention are designed. A hardware-in-the-loop test bench experiment has been taken under several skilled drivers to practice the established the brake pedal model with the operation data during the braking. Thus, it results a model indicating the braking intention by braking operation that means effectively improve the braking comfort and applies to the research of electronic braking system of commercial vehicle.

Heavy vehicles have the characteristics of with high center of gravity position, large weight and volume, wheelbase is too narrow relative to the body height and so on, so that they always prone to rollover. In response to the above heavy security problems of heavy vehicle in running process, this paper mainly analyzes roll stability and yaw stability mechanism of heavy vehicles and studies the influence of vehicle parameters on stability by establishing the vehicle dynamics model. At the same time, this paper focuses on heavy vehicles stability control methods based on simulation and differential braking technology. At last, verify the effect of heavy vehicle stability control by computer simulation. The results shows that self-developed stability control algorithm can control vehicle stability effectively, so that the heavy vehicles instability can be avoided, the vehicle driving safety and braking stability are improved.

To address the current situation of the limited driver-vehicle cooperative steering actuation structure, this paper proposes a feasible driver-vehicle shared steering control actuation architecture based on the differential steering. Firstly, a shared steering execution architecture is established, which contains traditional steering system controlled by human driver and differential steering system acting as the automatic execution system. In this paper, a specific driver-vehicle shared control architecture is established with the front-wheel hub motor-based differential steering system and a single-view angle based human driver model. Then, an upper-level sliding mode controller for path tracking is developed and implemented as the automatic steering system, and the driver-vehicle shared control is achieved by the proposed non-cooperative game model.

Adaptive cruise control is one of the key technologies in advanced driver assistance systems. However, improving the performance of autonomous driving systems requires addressing various challenges, such as maintaining the dynamic stability of the vehicle during the cruise process, accurately controlling the distance between the ego vehicle and the preceding vehicle, resisting the effects of nonlinear changes in longitudinal speed on system performance. To overcome these challenges, an adaptive cruise control strategy based on the Takagi-Sugeno fuzzy model with a focus on ensuring vehicle lateral stability is proposed. Firstly, a collaborative control model of adaptive cruise and lateral stability is established with desired acceleration and additional yaw moment as control inputs. Then, considering the effect of the nonlinear change of the longitudinal speed on the performance of the vehicle system.