Non-intrusive determination of shock absorber characteristic curves by means of evolutionary algorithms

The fault detection in the components of the suspension system of road vehicles is of great importance. The optimal performance of the suspension system has a big influence on the safety and stability of a vehicle. Vehicle inspection services make use of different methods of fault diagnosis of shock absorbers without the need to remove them from the vehicle. These methods generally provide an average value of the damping coefficient or a value related to the efficiency of the damper. Next, acceptance or rejection criteria are used to evaluate the condition of the damper. Consequently, there is currently no objective criterion for detecting the malfunctioning or faulty condition of shock absorbers. In this work, a novel methodology capable of obtaining the complete force-velocity characteristic curve of the shock absorber is proposed. For this purpose, the importance of using an appropriate tyre model to obtain the suspension parameters is first studied. In addition, the displacements of the sprung and unsprung masses and the excitation of the system are obtained experimentally. Next, the points that model the complete characteristic curve of a shock absorber are obtained by means of an optimization method based on evolu-tionary algorithms. Real tests have been conducted on a complete vehicle suspension test bench to verify the effectiveness of the proposed methodology.