3D Guidance Navigation and Human-Robot Shared Control for Motor Graders in Field Operation

Motor graders are widely used in road maintenance and airport constructions. With powerful hydraulic blades, they can be used to create wide and smooth surface with slope. Yet, it is time-consuming and labor-intensive to use motor grader because measuring, proofreading, driving, and grading occur at the same time during the grading process. Addressing this issue, we developed a 3D guidance navigation and human-robot shared control system to help automate the grading control based on the measurement and design data, only leaving the steering task to human drivers. This solution can improve the productivity, efficiency and safety while constructing with motor graders. Specifically, this solution leverages RTK (real-time kinematics) receiver and IMU (inertial measurement unit) sensor to locate the position of the blade, and compares it with the design map, while the controller is adjusting the blade position according to the error from the comparisons. With the blade driven by two separate hydraulic cylinders, the control is coupled, which causes a “seesaw” effect. That is, the motion of one cylinder will affect the other one and cause jittering. To solve this problem, we designed an elevation controller with angle compensation to decouple the process and used the fuzzy logic control to optimize the speed and response of the system. The system was tested and validated on an industrial motor grader in both pilot testing and real highway construction fields. The test results showed that blade control automation can eliminate the labor survey. The proposed human-robot shared control technique can be extensively used to increase efficiency, productivity and safety while decrease labor cost for field operations in semi-autonomous construction machinery, orchard mowers.