Comparative Evaluation on Effective Number of Active Suspension Actuators for Tracked Vehicle

The effective number of actuators required to control a tracked vehicle active suspension system based on a half vehicle model is studied. A two dimensional and two degree-of-freedom (2-DOF) linearized tracked vehicle model and several representations of road surface conditions, including haversine (bump/hole) and random road profile (RMS 2_09㎝) models are used in the simulation and analysis. The main goal of this research is to discover how to optimize the energy and cost required for effective control of tracked vehicle suspension systems, while maintaining closely approximated dynamic performance. The suspension systems are optimized with respect to ride comfort preference and suspension rattle space as expressed by the mean-squarevalues of body accelerations and suspension deflections. The dynamic performance and power demand of the active suspension system for a tracked vehicle with respect to six and two control actuators are evaluated and compared with each other and with that of a passive system using numerical simulation in time and frequency domain respectively. The results show that the dynamic performance for the active suspension system with two control actuators nearly follows that with six control actuators, while conserving a power demand of about one fifth that of the total power demand from the six control actuators. The strategy proposed here is taking full advantage of the fact that the systems in question, have only a two degree-of-freedom which means two controllers instead of six controllers is sufficient to obtain adequate system control. Frequency response curves to two types of road inputs, such as heaving and pitching, confirms the time domain response and also demonstrates the effectiveness of the two controllers’ suspension system on ride comfort. In addition, the effects of the six and two variable dampers on a semi active suspension system are also examined in this research.