Silicon Micro-gyroscope Manufacturing Error Power Compensation Method

Silicon micromechanical vibration gyroscopes have many advantages over the conventional gyroscopes, such as reduced size, light weight, low cost, high reliability, being able to be produced in batch and integrated with electronic circuits.At present, the domestic silicon micromacbined gyroscopes have't used in practical application. One of the reasons is low accuracy and poor repeatability caused by manufacturing imperfections. This dissertion researches on the influence of manufacturing imperfections and compensation methods for the silicon micromechanical vibration gyroscopes designed. The details are as follows:First of all, the mathematic model of microgyroscopes is established using lagrangian dynamics. On the basis of mechanical laws for micro gyroscopes, drive mechanism, detection principle and the influence of the mode parameter are studied. The manufacturing process of the designed gyroscopes is introduced briefly.Second, the mechanical coupling and mode errors caused by manufacturing imperfections are researched in details. In the mechanical coupling error, unbalanced distamce between the drive parallel plates will introduce unbalanced forces which conclude several frequency components, this can be cancled by increasing the stiffness of the structure connected with movable drive comb in sense direction. The quadrature error introduced by support beams has a strong impact on the performance of the gyroscope. On the other hand the influence of the structure thickness and beam width change to the mode frequencey difference is researched. Brownian noise and temporature error are also presented.Third, three kinds of orthogonal coupling error compensation technologies are studied, including the DC bias method, current compensation method and synchronous demodulator law. As synchronous demodulation method can effectively filter out the interference signal, overcome the noise in the detection channel, and doesn't need special components in the mechanical structure and complicated circuit, it's selected and puted to use in the quadrature error compensation plan of our gyroscopes.Fourth, with the theory of using negative stiffness to compensate mode error, analyze and simulation are made with the biased comb structure. Finally, the PCB of the synchronous demodulation method and negative stiffness adjusting method are designed and tested. The result of the experiment turned out that these two methods are effective to compensate the influence of manufacturing imperfections and improve the performance of silicon micromechanical gyroscope. At the same time, performance test data of silicon micromechanical vibration gyroscope is also presented.