Path-Following Controller for 4WDs Hydraulic Heavy-Duty Field Robots with Nonlinear Internal Dynamics

This paper describes a full closed-loop vehicle model for use in high precision path-following control of heavy-duty field robots. We present a high-performance path-following controller for four-wheeled drive (4WD), steer-articulated vehicles, typically used as mobile bases for aerial work platforms. Our control system promptly evaluates the curvature of the path the vehicle is about to navigate and regulates the wheels’ speeds accordingly to insure high performance execution while avoiding velocity saturation. Moreover, we illustrate the architecture of the developed control software and its integration into the vehicle’s proprietary control unit. We use a simulation model of the test-case robot to compare the developed controller to other path-follower candidates. Then, the controller is used in experiments to verify its feasibility in heavy-duty, 4WD-steered field robots having nonlinear internal dynamics and high inertia. Publicly available videos of the experiments disseminate the proposed controller performance in action.