Method of Improving Lateral Stability by Using Additional Yaw Moment of Semi-Trailer

Abstract

The lateral stability control of tractor semi-trailer plays a vital role for enhancing its driving safety, and the distributed electric drive structure of a hub motor creates opportunities and challenges for realising the lateral stability accurately. Based on the dynamics simulation software TruckSim, a nonlinear dynamic tractor semi-trailer model is established, and a MATLAB/Simulink linear three-degree-of-freedom monorail reference model is established. The upper controller adopts fuzzy proportional–integral–derivative control to export active yaw torque values of the tractor and semi-trailer. The lower controller outputs the driving/braking torque of each wheel according to the target wheel driving/braking rules and torque distribution rules. The tractor produce an active yaw torque through conventional differential braking the hub motor is installed on both sides of the semi-trailer, and the active yaw torque is produced by the coordinated control of the driving/braking torque of the hub motor and the differential braking of the mechanical braking system. To prevent wheel locking, the slip rate of each wheel is controlled. Finally, based on the TruckSim–MATLAB/Simulink cosimulation platform, cosimulation is performed under typical working conditions. The simulation results show that the control strategy proposed in this report is superior to the conventional differential braking control (ESP). It can not only improve the lateral stability of the vehicle more effectively, but also improve the roll stability.

Approximation Possibilities of Fuzzy Control Surfaces for Purpose of Implementation into Microcontrollers

“…The closer they are to zero, the more the ideal trajectory is tracked. Error area is area bordered by measured trajectory of the robot and line between start and Furthermore, if we in (5,6) replace the constant coordinate y TARGET by function y TARGET = f (x), where f (x) represents trajectory function, then the robot can move along the defined trajectory by this function. This solution is limited to trajectories, where for each x-coordinate is only one y-coordinate.…”

“…Therefore, when analyzing the impact of the fuzzy control surface method on the control quality of the EN20 mobile robot in real-world conditions, we set the maximum speed of both motors to 60%. The reason for limiting motor speeds to 60% is due to the robot's current limiter activation at acceleration to higher speeds to reduce the current supplied to the motor drives, thus reducing motors speed [6]. Because of this fact, the used identified mathematical model of the robot is relevant only up to 60% of maximum speed.…”

“…The first advantage of the fuzzy controller is the ability to control simultaneously multiple variables as was demonstrated in the design of omnidirectional mobile robot navigation [5]. The second advantage, specific to fuzzy control, is that it is not required to know the mathematical model of the controlled system [6,7]. This can be problematic with most of the linearizationbased and algebraic control algorithms when the dynamic system cannot be described for some reason.…”

Research on Decoupled Optimal Control of Straight-Line Driving Stability of Electric Vehicles Driven by Four-Wheel Hub Motors

“…Zheng Yuanbai et al installed the hub motor on both sides of the semi-trailer and generated the differential torque by coordinating and controlling the driving/braking torque of the hub motor and the differential braking of the mechanical braking system, so as to effectively improve the lateral stability of the vehicle. The research shows that this strategy is better than the traditional differential braking control system (ESP) [12] Zheng Yuanbai et al installed the hub motor on both sides of the semi-trailer and generated the differential torque by coordinating and controlling the driving/braking torque of the hub motor and the differential braking of the mechanical braking system, so as to effectively improve the lateral stability of the vehicle. The research shows that this strategy is better than the traditional differential braking control system (ESP) [12].…”

“…The research shows that this strategy is better than the traditional differential braking control system (ESP) [12] Zheng Yuanbai et al installed the hub motor on both sides of the semi-trailer and generated the differential torque by coordinating and controlling the driving/braking torque of the hub motor and the differential braking of the mechanical braking system, so as to effectively improve the lateral stability of the vehicle. The research shows that this strategy is better than the traditional differential braking control system (ESP) [12]. Ma Haiying et al studied the influence of different wind angles, crosswinds, and vehicle speeds on the straight-line driving of electric vehicles driven by four-wheel hub motors, and established a direct yaw moment control model based on fuzzy logic to improve the straight-line driving stability of electric vehicles driven by four-wheel in-wheel motors under crosswinds.…”