Presented is an improved version of the PID controller (PIDC) for DC motor control. The PIDC is a very cheap and easy controller to implement and is currently in use in many systems. There are instances whereby higher precision is required and an improved version of the PID can serve. The systems might not be necessary limited to marine systems. Hence, saving the need for more costly redesign. The PIDC proposed was compared with the PID. Results show that the PIDC has superior performance compared to the PID. Hence, it is an indication that the PID could still withstand future developments; that is maintaining its characteristics of simplicity and cheapness.

An inverted pendulum is a multivariable, unstable, nonlinear system that is used as a yardstick in control engineering laboratories to study, verify and confirm innovative control techniques. To implement a simple control algorithm, achieve upright stabilization and precise tracking control under external disturbances constitutes a serious challenge. Observer-based linear quadratic regulator (LQR) controller and linear matrix inequality (LMI) are proposed for the upright stabilization of the system. Simulation studies are performed using step input magnitude, and the results are analyzed. Time response specifications, integral square error (ISE), integral absolute error (IAE) and mean absolute error (MAE) were employed to investigate the performances of the proposed controllers. Based on the comparative analysis, the upright stabilization of the pendulum was achieved within the shortest possible time with both controllers however, the LMI controller exhibits better performances in both stabilization and robustness. Moreover, the LMI control scheme is effective and simple.