Motor Grader Blade Leveling Control Against Hydraulic Hysteresis
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Solution Overview
Problem
Existing motor graders experience poor leveling accuracy due to hydraulic system hysteresis, causing the shovel blade to change horizontal position during elevation adjustment, even when operating at a constant speed.
Innovation Solution
A leveling control method that determines the lifting speed of the shovel blade based on the current and target elevations, along with the movement speed of the motor grader, to ensure precise elevation control by adjusting the lifting oil cylinder accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the lifting oil cylinder adjusts the shovel blade elevation to the preset value, then the elevation control is achieved, but the horizontal position of the shovel blade changes due to hydraulic system hysteresis, resulting in poor leveling accuracy
Solution Approach 1:
The system performs preliminary action by predicting the future elevation of the shovel blade based on current elevation, hydraulic hysteresis characteristics, and motor grader speed. The controller calculates the required lifting speed in advance to compensate for the time delay caused by hydraulic system hysteresis, ensuring the shovel blade reaches the target elevation at the correct horizontal position.
Solution Approach 2:
The system implements feedback by continuously monitoring the current elevation of the shovel blade, comparing it with the target elevation, and adjusting the lifting speed dynamically. The controller uses real-time data from GPS receivers and sensors to modify the lifting oil cylinder's operation, compensating for hydraulic hysteresis and maintaining accurate leveling control.
2Measurement precision
If GPS receivers are arranged at both ends of the shovel blade to detect elevation in real time, then precise elevation detection is achieved, but the system complexity and cost increase
Solution Approach 1:
The system applies segmentation by dividing the elevation detection function into multiple components: one or more GPS receivers mounted on the motor grader body and additional sensors (accelerometers, gyroscopes) positioned at or near the shovel blade. This segmented approach distributes the measurement function across multiple simpler components rather than requiring complex dual-GPS blade-mounted systems.
Solution Approach 2:
The system uses intermediary sensors (accelerometers, gyroscopes, and mechanical linkages) to bridge the gap between the GPS receivers on the motor grader body and the shovel blade elevation measurement. These intermediaries translate the position and orientation changes of the motor grader into accurate shovel blade elevation data without requiring direct GPS mounting on the blade itself.
Data Source
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Figure 2
Figure 3a~3b
AI summary
The present disclosure relates to a leveling control method and system, a controller, a motor grader, and a computer storable medium, relating to the technical field of construction machinery. The leveling control method comprises: obtaining the elevation of the current position of a blade of a motor grader, the elevation of a target position, and the movement speed of the motor grader, respectively, said target position being on the ground which has a certain horizontal distance from the current position along the direction of movement of the motor grader (S110); according to the horizontal distance and the speed of movement, determining a time of movement of the blade from the current position to the target position (S120); according to the difference in elevation between the elevation of the target position and the elevation of the current position, and the movement time, determining the lifting/lowering speed of a lifting/lowering cylinder (S130); controlling the lifting/lowering cylinder according to the lifting/lowering speed, and adjusting the blade from the current position to the target position (S140). According to the present disclosure, leveling accuracy is improved.