Offset Excavator Control via Kinematic Transformation
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Solution Overview
Problem
Offset excavators with additional kinematic degrees of freedom pose challenges in precise leveling due to complexities in trajectory planning and control, as existing standard excavator assistance systems are not designed to handle the extra degree of freedom effectively, leading to inefficiencies and inaccuracies in leveling operations.
Innovation Solution
A method and device that utilize a standard excavator trajectory planner to generate control data for offset excavators by converting input data from offset kinematics to standard kinematics, allowing for precise trajectory planning and execution of leveling operations, even with simultaneous movement of the offset joint, by determining target deflection angles and angular velocities for actuators.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a standard excavator assistance system is used for offset excavators, then the system complexity is reduced and existing trajectory planners can be utilized, but the leveling precision deteriorates due to the additional kinematic degree of freedom
Solution Approach 1:
The patent introduces an intermediary coordinate transformation mechanism that converts offset excavator kinematics into standard excavator kinematics. A transformation matrix maps the additional degree of freedom from the offset joint into equivalent movements in the standard boom-stick-bucket coordinate system, allowing standard trajectory planners to handle offset excavators without modifying their core algorithms
Solution Approach 2:
The patent transforms the kinematic parameters by expressing offset excavator states (with 4 degrees of freedom) in terms of standard excavator parameters (with 3 degrees of freedom). The transformation dynamically adjusts the parameter representation based on the offset joint angle, enabling standard control systems to accommodate the additional degree of freedom through parameter redefinition rather than structural modification
2Productivity
If the offset joint is allowed to move simultaneously with boom and stick, then the productivity is improved through more flexible positioning, but the trajectory planning complexity increases
Solution Approach 1:
The patent makes the trajectory planner universal by designing it to handle both standard and offset excavator kinematics through a unified coordinate transformation framework. The same trajectory planning algorithm can be applied regardless of whether the offset joint is stationary or moving, as the transformation automatically adapts to the current kinematic configuration
Solution Approach 2:
The patent implements dynamic coordinate transformation that adapts in real-time based on the offset joint's position and movement. The transformation matrix is continuously updated according to the offset angle, allowing the system to dynamically handle simultaneous movement of the offset joint with boom and stick while maintaining trajectory accuracy
Data Source
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AI summary
A device (110) for a working machine (100) with an offset joint (203) is designed to perform an assistance function for leveling an environment of the working machine (100).