Design On Piezoelectric Feeder Driver Power And Speed Control

Piezoelectric feeders have been attracting widely application in automaticconvey with precision components because of their outstanding features such aslow noise, no magnetic interference, small size, fast response and so on. However,the research on piezoelectric feeders starts relatively late at home and the powerdriving technology is not as good as that abroad in stability and efficiency.Meanwhile, there has been little domestic research on vibration control forconstant conveying speed. Most existing ideas only propose amplitude sensors asresonant motion detection unit instead of improving the control algorithm.Consequently, the study has a very important guiding significance to domesticdevelopment of piezoelectric power feeder driving technology. This paper focuseson designing a stable power driver with high cost performance and presenting aconstant conveying speed control algorithm.In this dissertation, the design proposes ARM as the controller, uses uC/OS-IIembedded operating system to deal with the task and memory, and integrates theinverter’s mechanism, which also provides hardware platform for constantconveying speed control. A new design of driving power with adjusting amplitudeand frequency, human-machine function is presented according to the technicalrequirements of the piezoelectric feeders. And amplitude modulation is realized byadjusting the output voltage of the DAC switching, while frequency modulation isbased on regulating the on-off frequency of power switch tube in the invertercircuit through the SPWM control technology. Furthermore, by applying thedriving power to the piezoelectric feeder and carrying out testing experiments todeliver3528type LED, the processing results indicate the system reliability withsmooth output waveform and low heat generation.The vibration control theory is also studied in the thesis, and the piezoelectricfeeder’s dynamics model is established. Then the mathematical representation ofdisplacement-frequency equation and the system transfer function, which arederived from frequency response method, provide an accurate mathematical modelfor the system. Considering the approximate linearity between the conveyingamplitude and speed, a kind of PID algorithm is utilized into the vibration control.Driving frequency may be real-time adjusted with the resonant frequency tomaintain the conveying amplitude in certain range, and the system conveyingspeed will eventually be a certain kind of constant state. The ideal PIDcompensator transfer function is obtained with MATLAB simulation, and thedesired proportional coefficient, integral coefficient and differential coefficient are obtained in order to implement the control algorithm.