| In order to load a large number of rescue equipment,the body of fire trucks and rescue vehicles is often large,which brings about the defect of poor mobility.At the same time,the traditional fire rescue vehicles mostly use passive suspension system,which limits the vehicle's cross-country trafficability and is difficult to adapt to the complex road conditions.Based on the subproject of national key research and development plan(Project No.: 2016YFC0802900),this paper studies the suspension system of fire rescue vehicle,adopts candle type semi-active hydro pneumatic suspension system,analyzes its influence on the stability of the whole vehicle,and develops the optimal control strategy to improve the trafficability of fire rescue vehicle in special terrain.In this paper,firstly,the mathematical modeling method is used to study the single wheel 1/4 car body,and the variation law of the elastic force and damping force of the suspension system is obtained.It shows that the optimization effect of the relevant performance indexes can be achieved by controlling the damping of the suspension system,which provides theoretical support for the subsequent analysis of the whole vehicle.Based on the research of 1/4 car body,the influence of numerical changes of key components such as hydraulic cylinder and accumulator on the system is analyzed mathematically,and a 1/4 car body system model is built in AMESim,and the change rule of relevant performance indexes of suspension system is analyzed to verify the feasibility of the scheme.Then,the control strategy of suspension system is studied.LQR linear optimalcontrol strategy is used to control the optimal damping force of the system.Combined with the related knowledge of modern control theory,the mathematical model of the whole vehicle is established according to the mathematical model of 1/4 car body,and the corresponding control model is established to obtain the optimal control parameters based on the control strategy.The semi-active controller is designed and the random road model is established.The control law and the random road response result are obtained through the Simulink simulation,which proves the feasibility of the theoretical research and provides the theoretical basis for the later vehicle system control.In order to solve the problem that AMESim is not easy to develop damping controller and achieve the optimal control goal of the system,AMESim and Simulink are used to simulate the interaction of the control force(i.e.damping force)data of the system,so as to realize the semi-active control strategy and complete the observation of multiple objectives of the suspension system.Firstly,the simulation results of 1/4 car body show that LQR optimal control strategy has obvious optimization effect.Then,based on the joint simulation platform,the whole vehicle model(system model,controller model,road model,etc.)with passive suspension and semi-active suspension is established,and the stability of the whole vehicle model is analyzed.The simulation results of vehicle centroid acceleration,suspension dynamic deflection,lateral acceleration and other parameters under different working conditions are compared,which shows that the suspension system in this paper improves the whole vehicle Stability and off-road trafficability.Finally,a prototype of the fire rescue vehicle based on the candle type semi-active hydro pneumatic suspension system is developed.The suspension system is tested under random road and snake road surface.The data indicate that the parameters such as acceleration and inclination angle of the vehicle basically meet the requirements of the fire rescue vehicle running under certain conditions. |
PDF Full Text Request