Modeling and Control of a Wheel Loader With a Human-in-the-Loop Assessment Using Virtual Reality

Abstract

This paper presents dynamic modeling, controller design, and virtual reality (VR)-based human-in-the-loop real-time simulation for a wheel loader control system. In particular, a loader with electrohydraulic 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. A linear quadratic Gaussian based robust controller is designed for automatic bucket leveling to assist the operator by keeping the angle of the bucket leveled while the boom is in motion. The closed-loop control system design is tested with a nonlinear model in a real-time VR simulation. In the 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. The controller performance was assessed in the VR environment. As expected, the controller was found to provide a significant improvement in the accuracy of the bucket leveling, particularly in the case of a novice operator controlling the linkage motion. While prototypes cannot be eliminated, the VR simulation combined with realistic physics and control dynamics provided a useful tool for evaluating hydraulic systems and controls with less reliance on prototype machines.

Damping Multimode Switching Control of Semiactive Suspension for Vibration Reduction in a Wheel Loader

“…As mentioned before, the damping mode of the target shock absorber depends on the discrete statuses of the two high-speed switch electromagnetic valves; thus to obtain the optimal switching sequences of the discrete damping modes for the wheel loader semiactive axle suspension, the system hybrid model should be further established based on Equation (2). According to the description of the MLD framework [33], the general model form of the damping hybrid control process is given by…”

“…Because of the high working efficiency, good flexibility, and convenient operation, wheel loaders are often used in the construction and mining fields [1,2]. However, because the wheel loader often needs to be worked under off-road conditions, continuous exposure to the strong vibration caused by uneven road will reduce working efficiency and damage the drivers' health [3].…”

Modeling and Optimal Control of Heavy-Duty Powertrains

“…Digging forces during the bucket filling process are studied in [18] while in [15], [19] and [58] only the lift system hydraulics and the linkage dynamics are in focus. The effects of wheel loader operator skills on the Short Loading Cycle (SLC) efficiency are studied in [23].…”

Identifiability analysis of a tractor and single axle towed implement model

“…Engineers often develop mathematical models to characterize a physical system. In off-road vehicle applications, models have been developed for applications such as guidance controller design (Karkee and Steward, 2010), traction modeling (Book and Goering, 2000), ride and comfort evaluation , handling evaluation , and real-time driving simulators (Fales, et al, 2005;Hummel et al, 2005;Karimi and Mann, 2006;Karkee et al, 2009).…”

“…One of the most notable is the National Advanced Driving Simulator (NADS) at the University of Iowa, which provides a realistic environment for many types of studies (NADS, 2010). In off-road vehicle engineering specifically, there are several examples of the development of driving simulators (Fales, et al, 2005;Hummel et al, 2005;Karimi and Mann, 2006;Karkee et al, 2009). Real-time simulation faces the challenge of balancing model fidelity with computational resources, as the simulation time must keep up with the clock time.…”