Human–Machine Interface Based on Constraint Velocity Polytope for Safe and Efficient Operation of Large-Size Hydraulic Manipulator

Large-size hydraulic manipulators (LHMs) are widely used in construction areas, but the traditional on-site human–machine interfaces have poor performance problems in efficiency, safety, and usability due to dangers caused by complex obstacles and machine’s constraints. In this study, a uniform constraint velocity polytope (CVP) is introduced to represent the complex constraint information for complying with the machine’s limitations and avoiding collision with the obstacles. The models of the machine and surrounding obstacles are established to calculate the CVP in real-time with a safety margin. The CVP and commanded tool-center-point velocity are incorporated into a visual annotation and displayed in a newly designed augmented reality-based human–machine interface, so that the operator can observe the safe velocity region intuitively and improve the operational efficiency and safety level. The experiment and simulation tests verify the effectiveness of the proposed human–machine interface in improving operation efficiency, safety level, and subjective feeling.