Researches Of Design And Experiment On Feedback Controlling Rotating Flow Valve

With development of micro-electronic technologies, digital hydraulic valves has been invented because of the cheap SBC(Single board computer) and single chip and has been the bridge between controlling high power equipment and micro-electronic technology. Digital valves are used to control flow, pressure and direction directly by digital signal. Compared with the traditional hydraulic valve, digital valve is communicated with computer or single chip without DA transformer and it has high cost performance, insensitive to pollution, operational agility. Because it has so many advantages, it will be widely applied to hydraulic controlling in the future and is an important direction of liquid driving.In this article, a kind of revolving flow valve has been invented which is connected to step motor. When the single chip sends out pulse, the step motor rotates driving the valve core changing the area of valve orifice in order to modulate the flow. In this way, it can eliminate the mechanical transformer which is located between step motor and flow valve such as ball bearing or cam gear. By analyzing and calculating according to the structure of valve, the relationship between the valve orifice area and the step motor rotating angular has been acquired. In this way, the controlling way which controls the flow is changed to control the step motor rotating angular simplifying the controlling way. According to the principle of easily controlling, the single chip hardware circuit and controlling software have been designed. The feedback system are consisted of inlet and outlet pressure sensor, step motor rotating angular sensor, step motor, single chip and interface circuit. The single chip is the core of the system.The real time flow of the valve is calculated according to the formula. If the discharge coefficient C and the form parameter of throttle orifice m were not exactly chosen, the calculation result of real time flow is poor and the flow of the valve can not be controlled precisely. In this article, the experiment platform has been constructed. By the experiment, the discharge coefficient C and the form parameter m has been calculated. At last, they are plotted by the least square method and the functions are acquired. Single chip calculates the real time flow which is correspond to the coefficient C and form parameter m and computes the deviation by the comparison with the needed flow. Then according to the deviation, single chip calculates the step motor angular and drives the step motor to rotate in order to exactly control the flow of the valve.