U-NEXT: A User-Centered New Prototype for Walking Excavator Simulator.

The walking excavator is a highly complex construction machine, characterized by challenges in control, instruction, and operational safety. In this work, we implemented a virtual reality (VR) walking excavator simulator that integrates real hardware components with kinematic physics simulation. Using the simulator, we conducted two user studies. The first involved 45 participants and examined the effects of user perspectives on performance and preference. The second involved 12 participants and investigated the influence of video passthrough of the controllers. Results show that the choice of perspective should be task-dependent. Third-person view outperformed first-person view in the undercarriage task in which complex leg movements are needed. It supported better planning and allowed complete body visualization. However, it did not reduce motion sickness and was less preferred than first-person view for training. From the second user study, passthrough significantly improved controller learning compared to animated controllers, with participants making fewer errors when using the passthrough design. Based on these findings, we provide design recommendations for user perspectives and controller representation in VR-based training simulators.