Embedded Model Predictive Controller on Low-Cost Low-End Microcontroller for Electrical Drives

TL;DR

This paper demonstrates a cost-effective, memory-efficient embedded explicit MPC implementation on a low-cost microcontroller for motor speed control, outperforming traditional PI controllers in performance.

Contribution

It introduces an explicit MPC solution tailored for low-end microcontrollers, enabling advanced control in resource-constrained embedded systems.

Findings

Uses 40% RAM and 92% ROM for a prediction horizon of 3 samples

Achieves better control performance than PI controllers

Cost-effective implementation on a $5 microcontroller

Abstract

It is very well-known that the implementation of Model Predictive Controller (MPC) on embedded platforms is challenging due to the computational complexities associated while solving an optimization problem. Although, there are many efficient embedded implementations existing by now, but for faster, more dynamic and non-linear control applications, there is no cost-effective and memory efficient embedded solutions. In this paper, we show the implementation of embedded explicit MPC for a motor speed control application on a lowcost 8 bit PIC 18 series microcontroller which costs only $5. The offset-free explicit MPC is designed for reference tracking, constraints handling, and disturbance rejection. The developed control law is exported to low-level C code and utilized in HIL co-simulations. We present the results of memory demand and control performance under various operating scenarios. The presented results show that the developed embedded MPC utilize about 40% of RAM and 92% of ROM for prediction horizon up to 3 samples. The performance of developed MPC is compared with the conventional PI controller. Overall results show that the presented approach is cost-effective, portable, and gives better performance than the PI controller.