Use of Software/ Hardware-in-Loop Technique for Development of Semi-Active Suspension 2015-26-0007

A vehicle's suspension system is the basic component which decides its dynamic performance. It is designed to separate the vehicle body and its passengers or payload from vibrations arising due to road disturbances, at the same time to ensure that the tires stay in adequate contact with the road surface. Challenges in suspension design many a time's leads in a compromise between the conflicting demands of ride comfort and road holding. Vehicles having soft suspension isolate the vehicle body from the higher frequencies in suspension but reduce the ability of the dampers to control the wheel movements which leads to poor road holding. Conversely, hard suspension provides more road holding but transmits more of the suspension movement to the body; in turn provide a less comfortable ride.

The development of active/ semi active suspension has addressed both these needs and provides optimum level of ride comfort and road holding which results in the safety and driving pleasure.

This paper explains the development of a semi- active suspension control. The veDYNA vehicle model duly validated with road data is used to develop semi active suspension with extended Sky Hook Control logic and PID controller. To implement semi-active suspension system experimentally, MR (Magneto Rheological) damper is used here. The control logic is further validated initially with software in loop (SIL) technique and later with component hardware in loop (cHIL) technique.

In both techniques use of digital road profile is made to analyze the results in terms of ride comfort and road holding characteristics of suspension. For SIL technique model of MR damper is used. The other technique used here is component HIL, which integrates virtual and experimental tools so that the design, development and validation of semi active control is carried out in the more realistic manner. This development of suspension can be done in early phase of the vehicle development cycle with actual MR damper and without the need of a vehicle prototype. This technique consists of combining the actual physical components on loading rig in closed loop with vehicle dynamic model running in real time along with semi active suspension control logic. This technique can also be referred as “Component Hardware in the Loop” (cHIL)

This paper presents the use of different techniques for development of semi active suspension control.