Design And Implentmentation Of Magnetic Encoders

The development of motion control system drives the development of position angle sensor.As a typical position angle sensor,magnetic encoder with high performance has a profound impact on the development of servo drive,numerical control motor and military industry.Improving the precision and resolution of magnetic encoder are the focus of current research.In this thesis,a Hall-effect based absolute position off-axis magnetic encoder is designed and implemented.The designed magnetic encoder consists of signal generating module,signal processing module,a signal output module and a main control module.The multi-pole-to-magnetic grid of the dual code channel is used as the magnetic code channel,and the bilinear Hall element is used as the sensitive element.The component senses the changing magnetic field and the cursor principle is adopted to calculate the position angle.The magnetic encoder has a resolution of 16 bits and an accuracy of 1.698'.The overall design of magnetic encoder is proposed.Firstly,the design requirements of the magnetic encoder are put forward,and the overall structural design of the magnetic encoder is given.Then the whole structure of the magnetic encoder including the signal generation module,the signal processing module,the signal output module and the main control module is given.Finally,three kinds of solution algorithms are introduced.The design and implementation of magnetic encoder hardware is presented.Firstly,the overall hardware framework is analyzed,and then the circuit design of the main control module,data acquisition module,USB serial port module,RS485 module,and the design of JTAG/SWD download circuit and power supply module are given.The embedded software of the magnetic encoder is designed and implemented.Firstly,the overall framework of the software and then the software development environment is analyzed,software design of the core single-chip system module,ICMU data acquisition module,SPI module,USB serial port module and RS485 module is presented.The error compensation algorithm of magnetic encoder is investigated.The error of the magnetic encoder is trained based on the BP neural network algorithm to compensate the error of the magnetic encoder.Then BP neural network algorithm is optimized by particle swarm optimization algorithm to improve the error compensation performance.Finally,the algorithm is validated by experiments.The magnetic encoder was debugged and analyzed.Firstly,the modules of the hardware circuit of the magnetic encoder are debugged,the test platform is built and the ICMU sensor and the magnetic code disk are debugged,and the ICMU sensor data acquisition module,the USB data output module,the SPI communication module and the RS485 communication module are respectively tested.Then testing the speed,accuracy,resolution and other properties of the magnetic encoder.Finally,the performance of the error compensation algorithm of the magnetic encoder is verified.