Configuring a VR simulator for the evaluation of advanced human-machine interfaces for hydraulic excavators

This study is aimed at evaluating the impact of different technical solutions of a virtual reality simulator to support the assessment of advanced human-machine interfaces for hydraulic excavator based on a new coordinated control paradigm and haptic feedbacks. By mimicking the end-effector movements, the control is conceived to speed up the learning process for novice operators and to reduce the mental overload on those already trained. The design of the device can fail if ergonomics, usability and performance are not grounded on realistic simulations where the combination of visual, auditory and haptic feedbacks make the users feel like being in a real environment rather than a computer-generated one. For this reason, a testing campaign involving 10 subjects was designed to discriminate the optimal set-up for the hardware to ensure a higher immersion into the VR experience. Both the audio-video configurations of the simulator (head-mounted display and surround system vs. monitor and embedded speakers) and the two types of haptic feedback for the soil-bucket interaction (contact vs. shaker) are compared in three different scenarios. The performance of both the users and simulator are evaluated by processing subjective and objective data. The results show how the immersive set-up improves the users' efficiency and ergonomics without putting any extra mental or physical effort on them, while the preferred haptic feedback (contact) is not the more efficient one (shaker).