Non-Linear Proportional Integral Derivative Controller for Active Quarter Car Suspension System

Abstract

This thesis aims to see what kinds of performance improvements can be achieved using a non linear proportional integral derivative controller on quarter-car model suspensions for passenger car applications. To construct a control system for a quarter-car model with constant sprung mass, unsprung mass, damping coefficient, and tire stiffness has been created. Control objectives including sprung mass acceleration minimization and dynamic tire compression, as well as suspension travel. Dynamic tire compression is employed as a predictor of handling quality, whereas the sprung mass acceleration is used to indicate ride comfort. The performances of active suspension system with NPID were evaluated by comparing its respective passive suspension system (PSS). To investigate the effects of road profiles and vehicle speeds on ride comfort and road handling performances, three types of road excitation are designed. These are; random (type A, type B and type C) road inputs and predictable two bumps sinusoidal road inputs. For the random, type A (smooth), type B (good surface) and type C (average), road inputs were designed at four operating vehicle speeds (20km/hr, 40 km/hr, 60km/hr and 80 km/hr). The simulated MATLAB signal statics of peak to peak, .The simulated results of active suspension system and passive suspension system at selected vehicle speeds are investigated under selected random road inputs. Non-linear proportional integral derivative control methods is used to control both ride quality for comfort and vehicle handling can be highlighted by developing a mathematical model for a new design suspension system. As illustrated in the simulation, the comparison of active suspension system with non-linear proportional integral derivative controller is done to their respective passive suspension system for all road inputs and the controlled active suspension system improves ride comfort 66.31% and vehicle handling 95.85%. From this research, it can be concluded that the designed non-linear proportional integral derivative controller have excellent performance for a developed dynamic model, improving the ride quality for passenger safety and vehicle handling under different road disturbances and vehicle speed operations.