Design And Development Of Constant Torque Load Experimental Control System

As one of the most common loads in industries, constant torque load has been widely used in mechanical devices such as conveyor, crane, elevator, extruder and so on. It has mechanical feature of constant torque while its speed is liner to power. Generally speaking, this kind of load is more strictly to the accuracy of control system, so it makes great sense to design a proper control system.Magnetic brakes is used in this paper to simulate constant torque load in the real industries, and driven by a DC motor. Deadbeat controller is designed to archive two goals, when load keeps constant, system rotation speed can be regulated smoothly in a certain range. And when load changes from time to time in a certain range, system rotation speed can follow the given value and keep constant.To achive those targets, deadbeat controller is used. Fisrt step is to build model of the system, using identification method. This paper takes least squares method by step response. But the model itself is obviously not that accurate with a certain system errors for such a fast response system. Then PSO algorithm is used to optimize the system, nine sets of data are available by repeated independent experiments. Compared to the LS model, it is more coincided to the step response and gets a better control outback.Another main task of this paper is to bulid an experimental system, three parts are included, ie. hardware circuits, application programs on PC with USB interface, and HDL programs inner FPGA. For hardware circuits, power supply circuits, FPGA configuration circuits, ADC and DAC circuits are designed. Then, USB interface and application programs on PC are also designed to make it easier for interaction of human and PC. Next, this paper begins to design the inner HDL program in FPGA, VHDL is used. Modules are designed including SPI module, clock management module, data sampling module, D/A timing control module.Then, this paper concentrates on controller design, DSP Builder which is embedded in Matlab/Simulink as a toolbox is used to build deadbeat controller. After simulation, convert the design into VHDL module and add it into the FPGA project. Finally, load file generated from the FPGA project after compiling and simulation into FPGA and complete the whole design. After testing on the system, it achives good performance and satisfies the requirement.