Haptic Joystick for Improving Controllability of Remote-Operated Hydraulic Mobile Machinery

Remote operation of hydraulic non-road mobile machinery (NRMM) is becoming more and more common. The remote operation has plenty of advantages in many applications. However, a significant drawback of remote operation is that the level of sensory feedback for operator is weaker compared to onboard operation. The lack of the sense of touch is decreasing the working efficiency and can lead to premature wear out of machine components. This can also lower the safety of the operation. In this work a haptic joystick controller for controlling NRMM is introduced. The haptic joystick is able to feedback constant forces and wide range of vibrations for operators. The haptic feedback force is calculated based on the sensor signals from the working machine. This paper introduces a setup for remote operation of a wheel loader. The control of the lift and tilt cylinders of the bucket is taking advantage of haptic feedback. The experimental study is carried out in a virtual environment. A multibody dynamic model of the wheel loader is run in real-time to study the effects of haptic feedback for the remote operation. Results of the remote operation with and without haptic feedback are compared. The comparison shows that the haptic feedback clearly affects on the force levels and the loads of the boom structure of the remote operated wheel loader. Taking advantage of haptic feedback in controllers of remote operated NRMM increases the operator’s understanding about the dynamic behavior of the machinery significantly. The results encourages to carry out further studies on improving the human-machine-interfaces (HMI) of remote operated hydraulic NRMM using haptic feedback.