Steering/Braking Control of Articulated Vehicle for Small Turning

A wheel loaders is a kind of articulated-frame steered vehicles and is used in narrow workspaces such as livestock barns. Its small-radius turning performance is important for improving operating efficiency in narrow workspaces. An integral steering/braking control system for small-radius turning was developed in this study. In this system, braking force acts on the inside tires to make a yaw-moment around the vehicle centre of gravity. The braking force acting on the inside tires is controlled by a feedback control system of hydraulic pressure using an electro-magnetic relief valve. The relief valve is controlled by pulse width modulation to produce a desired hydraulic pressure. The control of braking force is only active when the articulation angle and vehicle speed are appropriate. Experimental results showed that the yaw-moment control allowed the articulated vehicle to turn in a smaller radius. The turning radius by the steering system with the yaw-moment control became at least 1.2 m smaller than the normal system on the wet unpaved road.