Modeling and control of a construction machine with a human-in-the-loop assessment in virtual reality

This paper presents dynamic modelling, control design, simulation results, and real time Virtual Reality (VR)-based human-in-the-loop testing for a wheel loader control system. In particular, a loader with electro-hydraulic actuation is considered. A detailed nonlinear dynamic model is developed for the hydraulic system and the loader linkage. The hydraulic model includes a load sensing pump, valves, and cylinders. The linkage model represents a two degree of freedom loader with lift and tilt functions. An LQG-based (Linear Quadratic Gaussian) robust controller is designed for automatic bucket levelling to assist the operator during the boom motion. The controller design is tested with a nonlinear model in a real-time VR simulation. In this VR simulation, the operator interacts with the model using a joystick input. The loader linkage geometry is displayed to the operator in real time using a VR display.