Coordinated Control Of The Electronic-Hydraulic Hybrid Anti-Lock Braking System For Electric-Wheel Vehicle

Automotive industry is desperately in need of corresponding transformation due to the energy crisis and environmental pollution; and the cause of this transformation is the need to change the dependence of traditional automobiles on unsustainable energy(like petroleum). Without any consumption of petroleum, electric vehicles are twice as high in energy conversion efficiency as traditional vehicles and have the advantages of non-exhaust emission, low noise and low thermal radiation. Meanwhile, electric vehicles are so designed that they can be easily maintained. Their compact size can also relieve traffic congestion in cities. Therefore, electric vehicles are one of the main directions of automotive industrial development in the future, with their R&D and application to transform the automotive industry.Originated in 1950 s, electrical wheel vehicles are a type of electric vehicles. They integrate power train, gearing and brake system on the wheel hubs, which can simplify the structure of vehicles, and allow for better chassis arrangement and car body styling. The in-wheel motors of electrical wheel vehicles may either generate power or produce brake force through energy recovery. Although they have fast response, their braking torque is inadequate. While the hydraulic brake system can produce larger braking torque, its speed of response and the accuracy of its braking torque are less than satisfactory. Besides, its hydraulic valve is liable to failure if operated too often. Therefore, if the advantages of these two systems are combined, a faster response and larger torque can be achieved, leading to better brake control. Since ABS has already become a common active safety system in vehicles, so research on the new type of ABS in electrical wheel vehicles is necessary.Taking Fiat Bravo as a prototype, aiming at the needs and features of ABS brake simulation, and based on vehicle dynamics, this study builds ABS simulation modeling through ADAMS: A new road identifier is designed through N-tic, it can accurately estimates road adhesive coefficients by various sensors of electrical wheel vehicles, which can transmit to the hydraulic-electrical control system for better domination of the upper controller. As for ABS control, dual-layer hydraulic-electrical ABS controller is created in this paper: the upper one adopts the fuzzy PID integrated with feed-forward control, calculating the requisite torque via sensors; and then, according to the distribution of logic, the lower one accepts the torque to control the motors and hydraulic brake torque. Besides, simulation tests of the dual-layer hydraulic-electrical ABS controller are implemented on well-distributed standard road, well-distributed low adhesive road, bisectional road and joint road, showing that the hydraulic-electrical ABS controller has better adaptability to various road surfaces, also has great robustness, stable control and can avoid heavy buffeting.