Experimental evaluation of modally distributed damping in heavy vehicles
This work presents theory as well as implementation of a modally distributed damping system with electronically controlled variable dampers. The presented approach follows from estimation of vehicle modal motions, through calculation of desirable modal damping forces to distribution of forces on the utilised dampers. The response time of the damping system is first evaluated in a damper test rig. The damping system is then implemented on a 4×2 tractor that is connected to a semi-trailer. Several road tests are performed to investigate how the system work under real driving conditions on a real vehicle, that includes nonlinearities and chassis frame flexibility that are theoretically unaccounted for, together with the limitations that comes with the control algorithm implementation. It is shown that the approach works and that it results in a considerable improvement for both the bounce and pitch modes, i.e. the system enables selecting damping for the sprung mass modes separately.