Influence of MR damper response time on semiactive suspension control efficiency

This paper tries to find the reasons of differences between results from semiactive suspension simulations and from real measurements. Simulations of semiactive algorithms which have already been published in many scientific papers have showned a great potential for improvement of the suspension quality. However, experiments with suspension controlled by semiactive algorithms which are supposed to improve grip did not bring any benefits. The reason of algorithm failure seems to be the response time of the damper used in the suspension. This paper compares the quality of suspension using three different semiactive algorithms (Skyhook, Groundhook, modified Groundhook) and passive settings for different damping levels. All the simulations were conducted for three different response times of MR damper: 1.5, 8 and 20 ms. Response time 20 ms is usual for commercial MR dampers control. Response time 8 ms corresponds to commercial MR dampers which are controlled by the newly developed PWM controller. Response time 1.5 ms corresponds to the fastest available MR devices. Simulations show a significant influence of the MR damper response time on the suspension quality if semiactive algorithms are used. The simulations are confirmed by measurements on a quarter car suspension controlled by modified Groundhook algorithm using MR damper with response time 8 and 20 ms.