This paper proposes a novel method for evaluating the performance of control modalities related to driving a wheel loader, according to the framework of Fitts’ law and the steering law. Fitts’ law is an empirical model for the evaluation of human performance. This model is widely used in human factors studies. The steering law is an extension of Fitts’ law, and this law is used especially for evaluating driving performance. To evaluate a driver’s performance, we carried out driving simulations of V-Shaped driving tasks based on ISO 5010 steering requirements. The simulation model of the Doosan DL400 class wheel loader was developed using an Open Dynamics Engine (ODE), and the steering performance of the model was tested with a human subject by using a driving simulator. The steering performance was analyzed with three different parameters: the maximum velocity, the steering ratio, and the friction coefficient. The simulation results show that the steering performance was consistent with both Fitts’ law and the steering law. The completion time was corrected linearly with an index of difficulty, with r2 being between 0.95 and 0.99. These results suggest that the proposed method is feasible for providing a quantitative tool that can be used to design the control modalities of wheel loaders.

This study introduces about development of multi-DOF ultrasonic motor that are composed of a bar-shaped stator and a spherical rotor. The ultrasonic motor is a motor which is operated by vibrations over frequency of 20kHz. The multi-DOF ultrasonic motor will be developed by expanding the basic theory of existing 1-DOF ultrasonic motor. It can generate 3-DOF rotation of the rotor around perpendicular axes using 3 vibration modes of stator. By using finite element methods, the optimal dimension of stator is decided and made the components of stator. When we apply the multi-DOF ultrasonic motor composed of rotor and stator to the driving test system, it will be checked whether the motor can be driven at the direction of 3-DOF or not. And it is proposed how the simulation of square bar shaped multi-DOF ultrasonic motor is accomplished.