| Summary: | 碩士 === 國立雲林科技大學 === 機械工程系碩士班 === 89 === In the hydraulic and pneumatic valves, the switching (or On-Off) solenoid is a widely-used electro-mechanical transducer, because of its significant features, such as low cost, large force output, compact design, robust construction and low requirement of maintenance. The Force/Stroke characteristic curve of switching solenoid, however, is quite nonlinear. Thus, it is not suitable to be integrated into a proportional valve directly.
The purpose of this thesis is to investigate the possibility of linearizing the Force/Stroke characteristic of a switching solenoid. Several control methods, such as PI control and Fuzzy control are proposed in this thesis. According to the test results, we have improved the performance of a switching solenoid and have achieved the same level of precision as that of a proportional solenoid. Thus, it can be integrated directly into proportional valves. Moreover, the pseudo force estimation function describing the relation of the Force/Stroke/Current of switching solenoid from experiment data is also established. Therefore, we can apply the pseudo force estimation function in the controller to predict the magnitude of the force directly from the values of the stroke and current of the switching solenoid. By applying pseudo force estimation function instead of the force sensor (Load Cell) which is relatively expensive, the cost of the proportional valve can be reduced. Consequently, such a product will be more competitive in the market.
|
|---|
