Study On DSP-based Data Acquisition And Processing Technology Of A Piezoelectric Six Degree-of-freedom Accelerometer

The six degree-of-freedom (DOF) acceleration of an object consists of 3-DOF linear acceleration and 3-DOF angular acceleration of the object's motion, which relatives to its inertial coordinate system, aiming to accurately reflect the motion trend of object. The 3-DOF linear velocity and angular velocity of the object's motion and the spatical location and posture of the object can be got and confirmed by doing an integral to the six-DOF acceleration once or twice. Hence, the six-axis accelerometers will be useful for the transportation monitoring, earthquake prediction, robot control, and weapons.In this dissertation, accoding to the sensing unit layout of piezoelectric six-DOF accelerometers based on six piezoelectric single-axis accelerometers, the data acquisition and processing system based on the DSP chipset TMS320F2812 as the core is desiged, which can not only collect the outputs from the multi-channel single-axis accelerations of the six-DOF accelerometer but also calculate the six-DOF acceleration. Moreover, in order to facilitate the connection between the six-DOF accelerometer and equipments, the analog output interfaces, USB interfaces, and UART interfaces are designed in the developed system.The major research works completed in this dissertation include:1. Accoding to the sensing unit layout of piezoelectric six-DOF accelerometers based on six piezoelectric single-axis accelerometers explored in our laboratory, the data acquisition and processing system based on the DSP as the core and with the CPLD is developed. The chipset TMS320F2812 is the main control chip of the hardware system to realize the functions of analog to digital conversion, algotithm processing, and the communication through combining the analog output interfaces, USB interfaces, and UART interfaces of the control output interface unit of XC95144. Therefore, the developed system offers a hardware platform for the realization of real-time processing and high-precision sensing of the six-DOF accelerometer.2. The data acquisition and processing software system section that consists of logic control system and data acquisition and processing system is desiged and explored. The logic control system can accomplish the DSP outer address coding and its logic control, the data acquisition and processing system can not only collect the outputs from the multi-channel single-axis accelerations of the six-DOF accelerometer but also calculate and output the six-DOF acceleration.3. In order to analyze the characteristics of the data acquisition and processing system, the experimental measurement system is set up. The characteristics of data acquisition and processing system are experimentally tested and analyzed through the developed measurement system. According to the experimental results, the designed data acquisition and processing system can not only collect the outputs from the multi-channel single-axis accelerations of the six-DOF accelerometer but also calculate the six-DOF acceleration. The calculated errors of linear accelerations and angular acceleration are less than 0.05 m/s2 and 0.05 rad/s2, respectively. In addition, the time delay of the DSP based data acquisition and processing system is less than 0.16 ms. That is to say, the data acquisition and processing system can meet the requirements of high precision and real time the six-DOF accelerometer.