Performance Comparison of the Iltis 1/4 T 4X4 Truck Equipped with Passive and Active Suspension Systems.

摘要

The purpose of this task was to develop a fully active suspension system for a CF vehicle and to implement a variety of control schemes in order to demonstrate the benefits of this technology. An active suspension system has been developed and fitted on an Iltis 1/4 ton 4X4 military truck. The vehicle has on-board hydraulics and an electronic control system. The hydraulic system consists of a reservoir and an engine-driven pump which supplies oil (15.2 MP) to accumulators and servo-actuators at each suspension assembly. The electronic control system is made up of transducers, an A/D card, a control computer, and analog control cards. The control computer calculates set points for the actuators, based on transducer input values, according to user specified control algorithms. A disturbance rejection algorithm was developed which reads and maintains individual actuator force values at initial levels, thereby providing good ride quality. Stability was enhanced by increasing the downward force on outside wheels in a turn based on body lateral acceleration and actuator force feedback. The vehicle is capable of outperforming a passively suspended Iltis in virtually all test conditions attempted. Maximum attainable speeds increased by 11 percent in a steady-state turn, 20 percent in a slalom manoeuvre, and a speed increase in excess of 100 percent was possible while keeping driver accelerations at equivalent levels. The active suspension system does add mechanical and hydraulic complexity to the vehicle. Consideration of an active suspension system for an in-service CF vehicle must weight the performance benefits against additional acquisition and life-cycle costs in well defined usage and mission scenarios.