Model Of Cylinder Controlled By On-Off Valve And System Of PWM Control

Pneumatic servo system is widely applied in the fields of civilian and military industry, aviation and aerospace etc. With the development of application technology, the pneumatic servo system is required to be miniaturized, fast and high precision controlled. For example, in the application of robot hand, small size, high output force and fast precise position control are needed. For solenoid valves applied in fluid control fields, it is necessary to realize proportional or servo control to press, flux or speed parameters. On this background, the investigation of the on-off valve PWM control system is put forward in this paper.Firstly, this paper reviewed the domestic and foreign development of the pneumatic servo technology and kinds of control valves. The pneumatic servo system and related technology, the sorts and features of control valves, the technology and research point of on-off valves are included. Some related theories, such as pneumatic pulse modulation, the principle and features of high-speed on-off valves and the working modes of valve control systems, are also been discussed in the paper. According to the theories of the electromagnetic, circuit and hydromechanics, the transformer of the high-speed on-off valve and valve control system is deduced. The models of single-terminal closed PWM pneumatic control system is set up in two different working modes. And the further Matlab/Simulink simulation is carried on. The simulation results show the static and dynamic features of the system are brought out, and the control strategy for high precision and high resolution output is concluded.Secondly, in order to build on-off valve PWM control system hardware platform, the hardware system is designed, with singlechip containing high resolution PWM module as its core. The singlechip is used to regulate the frequency and duty cycle of the PWM wave, modified the motivation amplitude of the on-off valve drive module and set the adjusting range via different air supply pressures and initial pressures for two cylinders. It can also be used to output the working parameters and modes by keyboard, which LED shows that information. For providing the research platform, the programs for the calculation of the position feedback and control strategy are worked out for the hardware design, in order that the system can realize high precision servo as the motion mode orders.Finally, several basic debugging and experiments are taken on the platform in the paper. The simulation results have been confirmed by the experiment results, proving the precision of the system design. According to the experiment results, the research on the control strategy for improving the precision and resolution is carried on, which strengthen the precision of the servo system.The paper can make contribution to the fields of pneumatic servo control and control theory. The product also has a wide prospect of business application.