Implementation of High Performance Microstepping Driver Using FPGA with the Aim of Realizing Accurate Control on a Linear Motion System

This paper presents an FPGA-based microstepping driver which drives a linear motion system with a smooth and precise way. Proposed driver built on a Spartan3 FPGA (XC3S400 core) development board from Xilinx. Implementation of driver realized by an FPGA and using Verilog hardware description language in the Xilinx ISE environment. The driver’s control behavior can be adapted just by altering Verilog scripts. In addition, a linear motion system developed (with 4？mm movement per motor revolution) and coupled it to the stepper motor. The performance of the driver is tested by measuring the distance traveled on linear motion system. The experimental results verified using hardware-in-loop Matlab and Xilinx cosimulation method. This driver accomplishes a firm and accurate control and is responsive. 1. Introduction Stepper motors are increasingly used in motion control because of their low price and the ability to position well a connected electromechanical system. Mainly, stepper motors are employed in an open-loop control system, where a lot of shortcomings appear, for example, block or leakage of position by overload, torque reduction by driving in operating range, great power dissipation, and lack of robustness by dynamic loads. At the moment, to solve these problems, closed-loop systems are used; there are sensorless closed-loop controlling systems which were developed to decrease the costs of stepper motor controlling systems. Here we have only the measurement of the phase currents and no encoder which is the most expensive device in such a control system. The control algorithm can build on different kinds of microprocessors. When the closed-loop driver is employed with a DSP via C language, the coding and debugging are straightforward. For such uses it is possible to use FPGAs, where we can unite software and hardware solutions to get better performances because of the parallel computing architecture of the FPGA [1–3]. By means of this technique, the programming and debugging are more challenging. Because of this, the performance of the FPGA-based driver is still limited. However, an FPGA-based driver with Verilog or VHDL code is easier in ASIC manufacturing. By using FPGA, it is likely to get a faster and more accurate control than it is possible with a microcontroller. Our aim is to improve a microstepping driver for stepper motors which is able to do microsteps in a stepper motor, so that effects like signs of age or the heat which influence the stepper effectiveness, have not any or very low influence on the driver. One more benefit of developing