Research On Control Method Of Full Active Suspension System Of Three-axle Vehicle Based On Front Terrain

The suspension system is one of the important components of vehicle chassis system,and its performance has a direct influence on the stability and ride comfort of the vehicle.Most of the existing emergency rescue vehicles apply passive suspension,which is difficult to meet the requirements of high-speed off-road driving.In contrast,the fully active suspension system with energy input and closed-loop control can adjust the suspension parameters in real time according to the front terrain,making the vehicle Maintain a good operating condition in the complex road environment.This paper combines the national key research and development plan "High-mobility emergency rescue vehicles(including fire-fighting vehicles)special chassis and suspension key technology research"(No.2016YFC0802902)to study the control method of the three-axis vehicle full active suspension system based on the front terrain to improve the stability and smooth ride of emergency rescue vehicles under high-speed off-road conditions.The main work of the paper is as follows:(1)In order to improve the displacement tracking accuracy of the suspension actuator,a compound control method combining feed compensation of input,feed-forward compensation of disturbance and closed loop feedback is designed.The effectiveness of the composite controller is verified by simulation and bench test,which lays a foundation for the displacement control of the actuator in the vehicle full active suspension system.(2)A control method for full active suspension system based on vehicle pose trajectory planning is proposed.Using the known elevation information of the front terrain,according to the control target and constraints of the suspension system,the vehicle pose trajectory parameterized by the cubic B-spline is planned in real time,and the corresponding suspension actuator elongation is solved at the same time.And when the time comes,the vehicle pose is adjusted and controlled by controlling the expansion and contraction of each actuator.(3)According to the performance requirements of the three-axle vehicle suspension system,select the appropriate state variables and system output to establish state space equation of a 1/6 vehicle two degrees of freedom and vehicle nine-degree-of-freedom full active suspension system,and also establish a block pavement model and random uneven pavement model.(4)Simulation analysis of the control method for fully active suspension system based on vehicle pose trajectory planning.For the 1/6 vehicle full active suspension system,the control simulation results show that the trajectory planning strategy can improve the performance of the suspension system,and it is not necessary to detect the long-distance front terrain information.For the three-axle vehicle full-active suspension system,the control simulation analysis is carried out with the block pavement and the random uneven road as the excitation,and the results show that the proposed suspension control method based on the vehicle pose trajectory planning can effectively handle the actuator output saturation and improve the performance of the suspension system,so that the vehicle has good body stability and ride comfort.