The Research Of The FPGA-Based Giant Magnetostrictive Actuator

Giant magnetostrictive actuator(GMA) is studied for precision drive, It is a new kind of actuator for improve auto control technic,quality and response of product.It not only could conquer the defect of traditionary magnetostrictive materials,also have the best electromotor transform efficiency.In the aspect of numerical control machine and precision machine,we can get a very precision numerical value.and the design is easier.Although many people study the system of control and mathematical model of actuator right now,there are a lot of aspects needed to do.This thsis is based on the study and analyse of the structure of Giant magnetostrictive actuator and its principle,we combine Verilog Hardware description Language(Verilog HDL) and FPGA,design the control system of GMA,and establish a new mathematical model about static electric current and displacement.Verilog HDL is language which used formalization method to describe digital circuit and design digital logic system.The designer of digital logic circuit could discribe his own idea via Verilog HDL,then use EDA tool to simulation.The study of my thesis about GMA is based on digital signals dispose technology and the quick evolution of control theory,it is adapt to the current at present—the stydy of intelligentize about GMA,it is also make use of FPGA's characteristic.all of this could make GMA more efficiency,more precision,more steady.The content of this paper is as below:Study the flex principium of GMA ,and analyse the structure of GMA,the bring forward the control scheme of drive system.Design the drive system of GMA,this system include hardware and software,and use Verilog HDL to design control system.The hardware circuit content is as below:(1)selecting the A/D converter chio and the interface t with FPGA,AD7705 use anΣ-Δconversion technique to realize up to 16bits of no missing codes performance.The selected input signal is applied to a proprietary,programmable-gain front end based around an analog modualator output is processed by an on-chip digital filter.The first notch of this digital filter can be programmed via anon-chip control register,allowing adjust of the filter cut off and output update rate.The AD7705 are ideal for use in smart,microcontroller,or DSP-based systems.they feature a serial interface that can be configured for 3-wire operation. Gain settings, signal polarity, and update rate selection can be configured in software using the input serial port. The part contains self-calibration and system calibration options to eliminate gain and offset errors on the part itself or in the system. (2) The design of the clock and reset circuit of the FPGA. (3) The circuit of keyboard and alarm.(4) temperature control system.then analyse the reliability of system.The software design the drive system follow the software design principle and process of FPGA. The software of the system divides into eight parts according to the function of the data collection system. They are as below:(1) The main program module is the main core of the system. The function of the main module is to combine the other module together and use the synthesize tool to optimize the system and fulfill the function of the whole system.(2) The displacement collection module: the basic function of this module is to initialize the AD7705 and to control this three AD7705 chips and make sure the chips work under the stable condition.(3) The digital filter module: main function of this module is to provide more accurate data by reducing the high- frequency noise signal to the control system of the respirator.(4) The monitoring module: monitor the status of the whole system, deal with unexpected situation happen to the respirator and protect the respirator.(5) The displacement equalize module: equalize the displacement because of heat. (6) temperature control module: control the temperature of system,let GMA work at a invariablenes temperature.In terms of this GMA drive system using FPGA, which can implement the parallel works and program in fields that means can update the system more easily, as the MCU, this system can provide more accurate and real-time signal to the control system what makes sleeping respirator more intelligent and effective to the patients. This system plays an important role in the applicationBased on the analytic about magnetostrictive flex offect, establish a new static mathematical model about staic current and displacement,and via simulation,it is all right.The question about GMA is quite complex,it is a long run before we acquire futher Success.with the development of our knowledge,I think we will have a good future.