| With the development of communication technology, wireless control technology has been widely adopted in mechanical engineering and is mainly applied in complex working condition and great labor-intensive occasions, Therefore researches on wireless control technology for special vehicles have practical significance.This paper consists of six chapters; the first chapter gives a brief introduction of home and aboard wireless control technology for special vehicle and the main content of this paper.In second chapter, the mechanical parts of special vehicle are separately designed. This paper focused on velocity wireless control technology for special vehicle without eliminating original manual control; achieve wireless control of speed through a remote device held by staffs away from the vehicle. To make the speed control of special vehicles rapid, accurate and reliable, so single-chip microcomputer is chosen as the core of the wireless control system. In the design of hydraulic oil system of vehicle speeder system, the high-speed switch valve is defined as implemental devices of electro-hydraulic conversion in throttle servo system, while the magnetic exchange valve is applied in gearshift devices. More importantly, these two valves are fit to connect single-chip microcomputer. Through the design of hydraulic oil system, the valves separately encode combinations to prepare for the wireless control of corresponding action of devices. Operators monitor the control platform screen which shows the driving environment captured by image acquisition device on vehicle. and then,according to the information obtained from the screen, remote driving control commands are sent by operators through remote controller to adjust the speed in time, so that vehicle can move as commands demand. This is the basic process of velocity remote control. Remote control commands are composed of two parts: The first, gearshift commands .The second, speeded up or down commands by throttle opening control.Analog variables are conducted to control throttle hydraulic cylinder, while the high-speed electromagnetic valve is used to achieve electro-hydraulic conversion. This paper introduces the principle of PWM and the PWM control of the high-speed electromagnetic valve, Numerical model of high-speed switching valve is built. Based on the analysis of the numerical model, main influence factors on spool valve are briefly discussed. Throttle servo system of the numerical model is built.The third Chapter is mainly about the design wireless control system, which includes the selection of the single-chip microcomputer (SCM). There are main principles of choice: first, the SCM should have a stronger anti-disturb ability. Since the wretched operating condition of the controlled vehicles, as well as the complex practical operating mode, are making important roles to disturb the SCM, so the selection of the SCM should adopt the types that have higher anti-disturb capability. The other one is higher performance-price ratio. The system selects the AT89S52 as the controller of the SCM finally. Then selection of the wireless module, because working conditions of the wireless vehicles are wretched, it demands a higher reliability of the data transmission. According to the transmission velocity, peripheral elements, power dissipation, and emission power synthetically, finally, the nRF2401 is selected as the core-chip of the wireless data transmission module. In addition, AD1674 is selected as the A/D transformer and is introduced particularly, and SPI interface is adopted as the connection of the SCM AT89S52 and nRF2401, the characteristics of this connect mode are that it could hand out the high effect of SPI interface, the advantage of the nRF2401 on the high velocity wireless transmission and the huge data throughput. The CUP only need input the data to SPI memory, and then could execute the other processes, it is unnecessary to emission the data for simulate the time-order and waste the CUP valuable time. But the error will be produced in the processing of SPI data transmitting, if the CUP initializes the nRF2401 by the SPI method directly, the success of the initialization will be lower, which possibly lead to the fail of data transmission. The solution of this problem is simulating 10k resistance connect the SPI interface when the hard ware circuit is designed, and the other end of the resistance connect the DATA port of the nRF2401, through which the resistance matching and isolation be achieved. The configure success ratio of the nRF2401 and velocity of the system data transmission will enhanced observably by adopting this interface method. The circuit, in paper, is introduced particularly in the hardware circuit design. It includes the interface circuit of the AT89S52 and nRF2401, interface circuit of the AT89S52 and AD1674, magnifying circuit of the magnet power, circuit of the proportional valve power magnifying and chopper steady flow, magnifying circuit of simulated signal; design of SCM replacement circuit; design of the keyboard circuit and adjusting circuit; design of the power circuit. Aside, some anti-disrupt measure on the hardware aspect are adopted. The forth chapter introduces the design of the software of the special vehicles wireless control system. The shifting process of the special vehicles can be divided into six steps: (1) Running at the original gear in pre-shift. (2) Diminutus accelerograph and separate the clutch. (3) Neutral position. (4) Shifting. (5) Join the clutch and accelerating. (6) Running at new gear. In order to shift smoothly, the compilation of (2)～(5) steps are the main jobs of the software design. The flows of the programs which relate to wireless data sending and receiving on the nRF2401 wireless transceiver are drawn respectively, and the program is compiled by C language.The fifth chapter is about the experiment and simulation. Firstly, Test the wireless communication is carried out. The test showed a data transmission distance of 160 meters. So, the system can be applied in the industry. After further analysis of the system error, the wireless radio frequency system shows a strong anti-error ability in burst. Secondly, the corresponding study of throttle servo system, a closed-loop system, is carried out.Simulation model of hydraulic throttle position servo system is set up by using MATLAB/SIMULINK software, through which a set of control parameters are determined by adjusting PID control module. Results show that (1) the control system has a good stability without any jitter and over-control phenomenon; (2) response time is about 0.5s; (3) there is a static error between maximum and minimum value, but within the scope of 5%. Finally, The A/D transportation system is simulated by using the SCM simulating software of proteus, and the result shows that the oscillogram of the simulation data on oscilloscope and the real data collected are same , which test and verify the reliability of the A/D transportation system in the data acquisition system.The sixth chapter gives the conclusion and prospect of the research. The main contents in the thesis are detailed summarized. The paper focuses on the technology of the special velocity wireless control, and makes the SCM as the heart of the wireless control system research. The operating system also includes turning and other functions in practical use, which are fresh research hotspot nowadays. Meanwhile, the improvement of the data transmission velocity and reliability are of practical significance. |
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