Synchronous Counting And Calibrating System Design For Pulse Output Of Multiple Inertial Measurement Unit

In order to satisfy some inertial measurement equipment manufacturers to test multiple inertial measurement units (IMU) at the same time, introducing a design for multichannel pulse signal synchronous counting and calibrating system. This design can effectively shorten the IMU product testing and calibration time.At the beginning of this paper discusse several commonly used schemes of pulse signal synchronous counting for4of IMU. After analysing advantages and disadvantages of these schemes proposing the actual system scheme to this project:By the FPGA chip EP3C16Q240C8and USB interface chip CY7C68013A as the core designing circuit board of inertial measurement unit pulse synchronization acquisition device, implementing the high-speed sampling of48channels pulse signal output by4of IMU. Each pulse seamless counting and5ms as a counting unit, then transmitting the data of48channels pulses count value to the computer by USB cable. Develop application program for user by VC++6.0. Real-time display of48channels pulse count value, the original data and per5ms count value recorded in the txt file at the same time. Finally calibrating the product according to the mathematical model and the test parameters, calculates the product scale factor and the drift rate, logged the results in the Excel files.Synchronous counting and calibrating system for pulse output of multiple Inertial Measurement Unit will be discussed into three parts:The first part is designning of multiple pulse synchronization acquisition circuit board, Including pulse receiving and signal processing circuit, FPGA peripheral circuit, The internal logic by QuartusⅡ9.0designed, USB interface technology and the peripheral circuit of CY7C68013A. The second part is the software design, This part include the firmware program when CY7C68013A in the SlaveFIFO mode and the application program. The firmware program is developed by the C programming language in the Keil software, implementing how to receiving, packing and transmitting48channels pulse signal. Application programe access the USB driver through interface function firstly, Then communicate with multiple IMU pulse synchronization counting system board. Finally, start the thread of receiving and processing of48channels data. The third part is based on the test object of this project—the dynamically tuned gyro assembly. Introduce the error model, calibration procedures and the method how to embed the calibration procedure into application program.Finally, the part of system debugging discuss some debugging problems encountered and solutions.After the analysis of operation performance for the test and calibration system.The results show that synchronous counting and calibrating system for pulse output of multiple inertial measurement unit meet the requirements of technical agreement.that has practical value.