Damping switching control with simplicity and high performance for semi-active suspension with time delay

Abstract

We investigated a damping switching control law with simplicity and high performance for semi-active suspension with time delay. The present law simply switches damping according to the sign of the condition function of ( + 0) using target and base velocity and 0, respectively, whereas a skyhook-based law does it by ( − 0). We conducted the simulations and experiments of vibration suppression for a single degree-of-freedom system with a semi-active magnetorheological damper to compare both the law. The key findings of this study are as follows: (1) In the time delay of 10–100 ms, the ON–OFF control using the present law maintains the vibration suppression performance under sine excitations although that using a skyhook-based law degrades it increasing with time delay. At least, over the time delay of 50 ms, the present law has the vibration suppression performance higher than a skyhook-based law in the overall range of frequency ratio of 0–4. (2) The velocity-proportional damping control using the present law shows the vibration suppression performance higher than or equal to the ON–OFF control using the present law under sine excitations. (3) Under a road surface excitation, the velocity-proportional damping control using the present law shows the ideal vibration suppression performance that the response displacement in the control is equal to that in the ON state around the natural frequency and close to that in the OFF state over the frequency ratio of √2.

Keywords

• semi-active suspention
• semi-active damper
• magnetorheological damper
• damping switching control
• skyhook-based control
• time delay