Design of Real-Time LQR Control for Rotary Inverted Pendulum System

This paper investigates the destabilizing effects of data communication discontinuities and packet loss on Networked Control Systems (NCS), a critical concern for real-time control applications. A real-time Linear Quadratic Regulator (LQR) controller is designed and implemented over a network for a Rotary Inverted Pendulum (RIP), an inherently unstable system. To address potential performance degradation caused by discontinuous measurements from packet loss, the robustness of the proposed controller is rigorously evaluated. Initially, a comprehensive simulation study using MATLAB/TrueTime 2.0 assessed the controller's ability to maintain RIP system stability under simulated network interference. Results demonstrate successful stabilization for packet loss rates up to 6%. Subsequently, a Hardware-in-the-Loop (HIL) experiment was conducted. The experiment used MATLAB/Simulink Desktop Real-Time to communicate with a remote I/O terminal via serial communication, introducing a representative 1% packet loss. The HIL experiment yielded an integrated absolute pendulum angle error of 28.38 degrees, validating the controller's effectiveness in mitigating packet loss effects and maintaining system stability under realistic conditions.