Optimization of Sliding Mode Control Parameters to Improve Passenger Comfort, Road Handling and Reduce Chattering in Active Electrohydraulic Suspension Systems

This paper presents a systematic optimization framework for Sliding Mode Control (SMC) parameters in Electro-Hydraulic Active Suspension Systems (EHASS), focusing on the critical balance between passenger comfort and road handling performance. The proposed methodology employs Particle Swarm Optimization (PSO) to address a key challenge in SMC-based suspension systems: achieving enhanced passenger comfort while managing the inherent trade-off with road handling precision. Our approach uniquely integrates ISO 2631 comfort standards into the optimization framework, ensuring that comfort improvements align with established industry benchmarks. Extensive validation across ten diverse road profiles demonstrated that the optimized controller achieves substantial improvements in comfort metrics, with 60% of test scenarios rated as 'Very Comfortable' compared to the conventional SMC system where 70% were rated as 'Extremely Uncomfortable'. While the optimization resulted in a moderate increase in tracking errors (maximum error of 0.1548m compared to 0.0014m in non-optimized cases), it successfully reduced control chattering by 85% and decreased Crest Factors from the 7.96-37.03 range to 2.22-7.38, well within ISO standards. These results demonstrate that our PSO-based optimization framework effectively balances the competing objectives of comfort and handling, providing a practical solution for modern automotive suspension systems.