Methods for optimization of heavy duty truck suspension design and control

Optimization of heavy duty truck suspensions is investigated using two different approaches. The first approach is optimization of the parameters of commonly used heavy truck suspensions to obtain improved overall performance. The second approach uses augmented active suspension elements in parallel with passive suspensions to obtain improved ride quality with low suspension input power. A method of control system design for the active element controller is demonstrated.; Parameter optimization of passive suspensions for improved overall performance uses four performance measures: pavement damage, ride comfort, stopping distance, and handling. The method uses numerical optimization methods and a complex heavy truck simulation program. Previous studies have used simple models, and have not considered overall vehicle performance. A sensitivity analysis is performed to help choose design variables, and twelve optimization cases are performed to demonstrate the method. This thesis shows that a complex heavy truck simulation model can be used for suspension optimization, and that significant improvements in each performance measure can be obtained for a typical tractor semitrailer. Also, a method for implementing roll and yaw stability performance measures as constraints in an optimization problem is demonstrated.; Augmented active suspensions are investigated using a twelve degree of freedom tractor semitrailer simulation model which was developed for this thesis. The passive suspension parameters are first optimized, then viscous damping is removed and replaced by active elements. Results show that ride quality can be improved by using augmented active suspensions. A method for using parameter optimization and optimal control methods to design the control system is demonstrated, and plots showing ride quality as a function of suspension input power are shown.