Design And Implementation Of Voice Coil Motor Servo System Based On FPGA

In view of the fact that the voice coil motor servo system is easily affected by uncertain factors such as external interference,nonlinear friction,inherent end impact,etc.,a mathematical model of the linear servo motor motion system with uncertainty is constructed.Direct frequency summation technology is adopted,the data stored in the.coe file is read by the internal ROM IP core of the FPGA,and the D/A converter is used to output the control signal.After the signal is amplified by the power drive circuit,the voice coil motor is driven to move.The raster encoder is used for position detection,and the position signal is collected by the FPGA.Write a program in the FPGA pair to solve for the position signal.For a closed-loop study,the actual position is diffed from the given signal.After the closed-loop control is realized,the research on the control strategy can be carried out.In terms of platform design,FPGA-xc7a35 t is used as the controller,the voice coil motor is a linear motor,and an encoder with a precision of 0.5μm is used inside.The drive circuit board powered by ±24V is designed,including current sampling circuit,comparison circuit,protection circuit and power amplifier for driving the voice coil motor.For the test of the drive circuit,firstly,the input signal of a fixed frequency is used,and the relationship between the input and output voltage of the amplifier circuit is tested with the resistance of 150Ω and 75 Ω,and then the sinusoidal signal of different frequency is used as the input to ensure that the load resistance remains unchanged,the amplifying performance of the amplifying circuit under variable frequency input signal was tested.For the control strategy,complementary sliding mode surfaces are established on the basis of sliding mode control.In order to make the anti-interference ability of the control system stronger,it was decided to add an extended state observer.The complementary sliding mode surface of the complementary sliding mode control is designed for the sliding mode surface of the original control algorithm,and the control rate can be derived after the establishment is completed.According to the research experience,this control strategy can improve the control precision,enhance the robustness,speed up the rise time of the system,and reduce the error.In addition,in order to avoid the problem of system vibration,the saturation function is selected for switching.The observation variable of the extended state observer is the total disturbance of the system.After observing the uncertain factors,it returns to the control loop.In Simulink,the hdl coder module library is used to build the control strategy,and the simulation analysis is performed.After completion,the code is generated and optimized in Vivado.In terms of experimental verification,the step signal and the sinusoidal signal are used as input signals respectively,and the complementary sliding mode algorithm and the complementary sliding mode algorithm with state observer are compared.Experiments show that the latter is more robust,indicating that this design is effective.The system incorporating the observer is not only more immune to disturbances,but also has a faster rise time.