| Air suspension can decrease the vibration noise and wheel dynamic load of the vehicle. The vehicle with air suspension can get ideal frequency. Through the control of the air spring, the ideal suspension characteristics curve can be achieved. Because the driving performance and security are all better, the application is much wide. This paper adopted the CAN-BUS and fuzzy control algorithm in order to control the half-initiative air spring suspension, further to make the driving performance and security much better.To the truck with the Electronic Controlled Air Suspension System, the matching design of the suspension and the control strategy are very important. This paper was completed based on the innovative fund supported project of Jilin University:"Matching Design and Control for Commercial Vehicle with Electronic Controlled Air Suspension System". In this paper, by matching and designing air suspension for a type of traditional truck, the general design method and key points for the leaf spring trailing arm two-air-bags type rear air suspension are summarized. And the ECAS Control strategy and Algorithm are researched with the project: Research on the Control Strategy and Algorithm of Electronic Control Air Suspension System for Heavy Truck.Air Suspension is composed by air spring, oriented structure, electromagnetic valve, absorber, sensor, air tank which are mechanical component and electronic component. According the demand of air suspension development of electronic control of commercial vehicle, we assign the structure of suspension by fewer metal plate springs at front and air spring at back. We made the characteristic test of air spring and design of application by which data we made systemic analysis before we brought out the new method of curve draft combine of air suspension characteristic when we develop the application software of application design of air suspension which had compared by the result of simulation and test data. We can bring out the air suspension characteristic by the dynamics parameter because we have done the analyzable and programmable of air suspension characteristic, so it make the develop duration of air suspension shorter and the number of human or stuff fewer.We made the model of multi-component dynamics of air suspension of vehicle by the software foundation of ADAMS/Car. This paper will test the tire of prototype vehicle (the triangle tire of 11.00R20-16P.R. made by Weihai) in tire test-bed and build the model of multi-component dynamics of tire radius rigidity because the tire is sensitive with vehicle's smooth .So we can make advanced model such as fewer metal plate spring, steering, dynamics, road which can be combined with simulation model and tire model of air suspension so do the simulation analysis of vehicle smooth. Utilize the data gotten from simulation and solid car test we can acquire the three directional weighting acceleration root-mean square value of both seat. The results are approximate, change tendency is substantial in agreement, prove the validity of the virtual prototype model, that is, it can exactly describe the dynamics performance of entire car. At the same time, inherent frequencies of the air suspension when it is empty and full load are gotten from simulation and test, and it proves the ride performance indicator of the heave truck air suspension adhere to specification, come to the desired result. For further control research of heavy truck air suspension provides foundation.Then to do the building block design for the control strategy of the entire car about the truck: Initiating control module;Parking module; Steering control module; Trimming control module. In the electrical control air suspension system, the center of the exactly regulate the body height and the stiffness of air spring is the timing of electromagnetic valve and the length of recharge cycle.Owing to electromagnetic valve possess major air intake and air outlet, ECAS system can quickly regulate height or pressure, but at the same time it fills the airbag with excess air and then make the regulating error. So in the process of regulating the air spring height or pressure, far from regulate object bring long fill deflation impulse , quick regulating speed, advance regulative real time quality; when it will reach regulate object , selecting short charge pulse period , decreasing quantity of filling and letting down the regulation speed, thereby advancing accuracy of regulation.According to the demand of air suspension control system, ascertain the CAN bus network topology of the air suspension system, select the hardware to realize can bus node function. Adopt drive chip SJA1000 generated in the PHILIP Corporation as can controller and adopt AT89C52 SCM as CAN node micro computer control units and transceiver adopt drive chip TJA1040 of the PHILIP Corporation. Base on JI939 agreement, design the PDU code of the CAN bus air suspension control system message, plus starting frame, controlling field, CRC field, answer field and frame finish field and do the homologous software design, then get the whole CAN message code. These provide the communication foundation to the air suspension entire car control test and rig test.Using Infineon (Infineon) XC167CI Series MCU as CPU, design and development of electronically controlled air suspension control unit, control unit (ECU) design also includes power circuit design, input-output channel design, reset circuit design, CAN bus interface circuit. Under the proposed control strategies to develop the corresponding control software. According to CAN bus air suspension vehicle control system layout, using self-developed suspension control unit (ECU) and WABCO Company's highly sensor and solenoid valve, and other air suspension components, which constructed electronically controlled air suspension system that tests bench, electronically controlled air suspension system control strategy. The verification test that part of the proposed control, algorithm validated the effectiveness. Results show that the development of the electronically controlled air suspension system can quickly and accurately achieve control objectives, the various working conditions are better coverage, and researching results achieved scheduled requirements.For further advancing the ride performance of the entire car, put forward the fuzzy control strategy and carry out the simulate analyses and research. Ascertain the input/output of fuzzy controller, design and exploit the self-regulation fuzzy controller, then realize self-regulation to the parameter and control law. The seven-freedom vehicle model is created. Refer to the automobile Theory and some other articles, created the road input of white noise, the B and D class road and the mixture of the two class roads. The simulation models of the vehicle suspension, and the fuzzy control process were created, the air spring level control with Matlab/Simulink toolboxes and modules. Both the road test data and the simulation data proved that the air suspension vehicle has under steer characteristic,and the roll angle of body satisfied the design goal. The natural frequencies of the air suspension under full load and empty load conditions and the ride comfort performance of the air suspension vehicle are also satisfied the design goal. The test data and the simulation data are approximate both in value and trend,this proves the correctness and sufficient accuracy of the full vehicle virtual prototype model,and so,the model can used to be a basis for further researches in air suspension optimization. The result indicates that the fuzzy control had less help to the body vibration on the good rood such as B class road, and had the better benefit on the bad road such as D class road. Based on the vehicle dynamic model and the control strategy, The ECAS test-bed of heavy truck is designed with the WABCO products such as solenoid values and level sensors, and the ECU of the Electronic Control Air Suspension system. The conclusion indicated that the air spring control strategy and Algorithm constructed had better effect to improve the body stability. The fuzzy control algorithm can make the effective improvement to the body vertical vibration acceleration. The ECAS constructed can response to the real driving conditions quickly, which realized the control strategy effective.The research of the matching design of the suspension and the control strategy is better for enhancing the capability of independent exploitation. It is very important to reduce the cycle of the product exploitation effectively.
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