Related Issues Of Measuring And Controlling Based On DSP For A Micromachined Electrostatically Suspended Gyroscope

Recently, with the wide use of micro-electro-mechanical(MEMS) technology in the field of a micromechanical gyroscope, a novel micromachined gyroscope with an electrostatically suspended rotor is being studied deeply at home and abroad. Employing gyroscopic effect of the high speed rotational rotor, a micromachined electrostatically suspended gyroscope can detect the angular rate and the linear acceleration of the carrier.By means of the differential capacitance of the microgyro, the angular rate and acceleration of the carrier are then transferred into the capacitive alteration related, furthermore, into electrical output. According to the differential capacitance of the gyroscope, The thesis mainly discusses the related techniques of detection and control of the microgyro by using the method of the digital signal processing and DSP chipThe main research content and results of this thesis are as follows:Firstly, this paper introduces the capacitive structure and the working principle of the micromachined electrostatically suspended gyroscope. The dynamical equations of microgyro in angular and linear movement are also given .it discusses the detection and control of the microgyro with the technology of digital signal processing. Secondly, it shows the principle of digital demodulation. Given the structure of this microgyro, the algorithm of autocorrelation detection is used to detect its signal.A synchronous amplitude detection system, which is based on DSP, is constructed .Proved by the experiment, this system can meet the demand of the detection of the micromachined electrostatically suspended gyroscope.Finally, the incremental PID controller is designed in order to achieve the close loop-control for this microgyro. Based on the development platform of VC33 DSP, a visual control system with the PID control algorithm is developed. To construct the system ,the major tasks are to program application codes about the peripheral chips of VC33 DSP, which are the MAX125 chip,the DAC7724 chip and the CY7C09449PV chip. This system mainly includes the following parts: A visual interface with VC++, which can transfer the data and commands.is Programmed by using VC++, A communication in PC and DSP is attained by programming the application codes to develop CY7C09449 chip . Using the specific Assembly language for VC33, the codes achieving the incremental PID controller is written. It also includes the application codes for A/D chip and D/A chip to obtain the function of input and output of the data processed. Proved by the experiment, this visual control system can run effectively. In this system, parameters of PID controller can changed swiftly and the result of PID controller can be seen in real-time. Consequently, it provides the effective method to complete the five channels close-loop control for the micromachined electrostatically suspended gyroscope.The control system discussed in this thesis has some main advantages below:(1) About the detection, the difficulty of giving a carrier frequency with the same frequency in the technology of analog amplitude demodulation can be avoided in this detection system which is based on the correlate algorithm using DSP. It also can avoid the frequency error and the phase error brought by analog devices concerned. (2) About the close-loop control system, the visual control can master the control result timely. It also can change the control parameters in time. (3)Both signal detection and close-loop control, it is easier to achieve multiple channels detection and control by copying and modifying algorithms of signal detection and close-loop control concerned.