Electro-hydraulic Steering Control System of the All-terrain Double Compartments Tracked Vehicles
|Course||Mechanical and Electronic Engineering|
|Keywords||All-terrain double tracked truck Electro-hydraulic proportional Pulse Width Modulation (PWM) Integral Separation PID|
China is a great country having Vast territory and Many disaster, especially in recent years with the increasing destruction of natural. We urgently need the all-terrain vehicles which can be driven into the isolated areas, when the disaster happened. On the other hand, a lot of resources distributed in the inaccessible areas. In order to develop of these resources, we also need these kind of all-terrain vehicles.The development of the all-terrain vehicles in china has just started. The representative products is the all-terrain double compartment tracked vehicle named as "Python-style", which is produced by the North Special Vehicle Manufacturing Company of Harbin. The vehicle has superior performance. But the vehicle’s steering system is old and obsolete, which will increasing the trouble of driving in the wild. Therefore, in this article, we committed electro-hydraulic proportional control technology which is advanced in the word on existing vehicle steering control system.Firstly, In the chapterⅡof this article we established the design scheme of Electro-hydraulic steering control system of the all-terrain double compartment tracked vehicles. The control signals which is collected from the steering angle sensor through the A/D conversion transmitted to the controller of steering operation for processing. Control signals are converted into 232 signal at single chip, then converted into a CAN 2.0 bus signals by CAN conversion produced by S & P e-card company. The CAN 2.0 bus signals transmitted to the Steering Controller by twisted wire. Then it computed in the PID algorithm there. Then the processed signals were sent to a power amplifier which can driver the E5E pilot electro-hydraulic proportional direction valves which can control the hydraulic cylinder motion. In addition, we also design a circuit diagram according to the design scheme, and a program for SCM.Secondly, In the chapterⅢof this article we calculated the steering resistance torque of the all-terrain double compartment tracked vehicles. when the vehicles in the clay ground and the vehicle is stationary, the Steering resistance torque is the largest. We have to establish the model of calculation in this condition. The Steering resistance is constituted by two part, which is the resistance torque caused by Track friction with the ground and the resistance torque caused by the Track moving the earth in the edge. The force of hydraulic cylinder can be calculated with the steering resistance torque we got above.Thirdly, in the chapterⅣof this article, we established mathematical models for both the electro-hydraulic proportional direction valve and steering hydraulic cylinder. The model of the electro-hydraulic proportional direction valve is established with the data provided by the DUPLOMATIC company; and the other model is established with the data which is more complex. Some of these data is collected from the database of the steering hydraulic cylinder, and some others were calculated, such as the equivalent mass of piston. Combining with the data of hydraulic cylinder we can finally get the transfer function of hydraulic cylinder.Fourthly, in chapterⅤof this article, after the integrating the transfer function above we get the ultimate mathematical model. And on this basis we can establish the PID controller design. Then a lot of work about calculating and simulating have be done after that. And we got a more optimized PID controller. Then the optimization methods of integral separation were added into the PID controller, which made the response of the system more faster and accurate.Finally, in chapterⅥof this article, the proportional control power amplifier of the steering control system were designed. In the part, we used pulse width modulation (PWM) technology to achieve power amplifier. And the current regulator circuit of the amplifier can make the current stable with the feedback of the output current.