FPGA-based control system for miniature robots

Resource-constrained miniature robots require small but high-performance onboard processing unit and reconfigurable electrical hardware to carry out different missions. The advances in Field Programmable Gate Array (FPGA) technology offer a system on programmable chip (SOPC) solution to this demand. This paper describes the technical achievement in developing FPGA-based control system which utilizes the hardware/software re-configurable feature of the advanced FPGA device to achieve the goal. We have implemented the hardware module inside the FPGA chip to generate PWM output and to count quadrate encoder pulses, which are the basic building blocks to drive DC motors. Software is developed to implement PID control algorithm using the PWM-Encoder module and on-chip processor. The functional correctness of the closed-loop control system is verified by the experimental tests. The performance analysis shows that the hardware module occupies less FPGA space and the power dissipation is very much comparable to other design alternatives of similar caliber. The preliminary results demonstrate that the PWM-Encoder module, in the form of user Intellectual Property (IP), can be duplicated and re-configured to control as many motors as needed. The success gives us a confidence boost to continue our effort to build user IP library for robotics applications which will benefit the robotics community by providing development tools and FPGA building blocks to satisfy the demand for an extremely flexible, high-performance, onboard computing unit.