Abstract
In recent years, motor vehicles industry has shown a tendency of replacing electromechanical components by mechatronic systems with intelligent and autonomous properties. This replacement is characterized by the integration of hardware components and implementation of advance control functions. In this paper, we have applied the system approach and system engineering methods in the initial phase of vehicle semi-active suspension development. An emphasis has been placed upon the interrelations between computer-aided simulation and other elements of development process. The benefits of application of suspension simulation are numerous: reduction of time to market, the new and improved functions of mechatronic components/devices, as well as the increased system reliability. This stresses the importance of system approach and justifies the cost associated with it.
Semi-active suspension systems are widely accepted in vehicle design due to their advantages when it comes to handling, ride, comfort improvement and finally, safety aspects. These performances improvement is achieved at a very low cost, as compared to that of the fully active system. The basis of a semi-active system is the controller, that is to be designed in such a way as to be able to successfully function in different conditions of vehicle movement. At designing of the above-mentioned system we used the one-quarter vehicle model, with an electronically controlled variable damper. This model, without any significant error, enables the model linearisation.
We have analysed several different control strategies, mainly based on the skyhook control. In suspension model development, we have used CAD/CAE tools and methods, as well as the multipurpose simulation programmes. For the simulation of suspension system we used the Matlab program package. We have listed the principal advantages of semi-active suspension systems that we reached through the simulation and laboratory testing.