Comparative Analysis of MPC and Integrated Skyhook-LQR Controllers for a CDC Damper Suspension System in Passenger Cars

Abstract

The performance of vehicle suspension systems is critical for ride comfort, handling stability, and safety. Passive suspensions, while simple and reliable, lack adaptability to road conditions, whereas fully active suspensions provide superior performance but are impractical for passenger vehicles due to high energy consumption. Semi-active suspensions offer a balance by dynamically adjusting damping forces with minimal power requirements, but their effectiveness depends on the chosen control strategy. This study evaluates two advanced control strategies: Model Predictive Control (MPC) and an integrated Skyhook-Linear Quadratic Regulator (LQR) controller. A seven-degree-of-freedom (7-DOF) full-vehicle model is developed using Lagrange’s equations to analyze vehicle dynamics. MPC is formulated as a predictive controller that anticipates road disturbances, while the integrated Skyhook-LQR controller combines classical Skyhook damping with optimal state feedback for improved stability. The controllers are implemented in a CarSim-Simulink simulation environment and tested under various road conditions. To assess real-world feasibility, experimental testing is conducted on a passenger vehicle equipped with semi-active CDC dampers using the Skyhook-LQR controller. The comparative analysis highlights key trade-offs. MPC provides superior predictive control and optimizes suspension performance across multiple axes but requires high computational power, limiting real-time implementation. The integrated Skyhook-LQR controller, while computationally efficient and practical for embedded systems, has limitations in handling complex disturbances. These findings underscore the importance of selecting control strategies based on application requirements. While MPC enhances ride comfort and stability, Skyhook-LQR remains a more feasible real-time solution. This study contributes to the advancement of semi-active suspension technology, offering insights for future vehicle suspension designs.