This manuscript establishes a methodology that guides the designers to develop an optimal controller for a semiactive suspension system. The methodology’s processes are generally explained and straightforwardly, so a designer can extrapolate the methodology to a specific problem. Furthermore, this research presents an optimal control strategy for a semiactive control applied to a quarter vehicle model as an example of using the methodology. A particular interest is made in the advantages of such a simple synthesis and in the compromises that must be done in skyhook and groundhook control law applications. This manuscript exposes a logical and straightforward approach for choosing the controllers’ design parameters; also, efforts must be made to express precise performance specifications and constraints in the control design. The herein methodology could be relevant in the process design for intelligent suspensions, from one-quarter toward the entire vehicle.

Intelligent suspension systems assist in decreasing the impact of road disturbances on passenger comfort, and its design requires a mathematical analysis that includes the elements of the suspension and the passenger's vertical dynamics. The contribution of this research is to merge a 4 degrees-of-freedom (DOF) Boileau-Rakheja biodynamic passenger model with a 3-DOF suspension model to generate more accurate representations of the displacements and accelerations of the main passenger's masses. Moreover, the contribution is complemented with a Skyhook controller in a semi-active 7-DOF one-quarter vehicle suspension to improve passenger comfort, and a case study presents tests in frequency and time domains. The analysis was conducted by establishing a regulatory closed-loop feedback control for a state-space system, simulating its behavior using MATLAB/Simulink, and comparing the results against specific performance criteria. The active suspension's frequency response showed a 40% reduction in the displacement transmissibility of the suspended masses at low frequencies (0-4 Hz), but exhibited a 2-10% increase in the rms acceleration at high frequencies (4-15 Hz). The herein results could be the base for further studies in the passenger comfort and road holding for one quarter, but also for half and full vehicle.

No abstract

No abstract