Work Machine Posture Computing Apparatus for Stable Excavation Control
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Solution Overview
Problem
Existing work machines, such as excavators, face challenges in accurately controlling the position of their work implements to prevent excavation beyond designated boundaries, particularly when the machine is in motion, due to rapid changes in posture angles detected by IMUs, leading to instability in position detection.
Innovation Solution
A posture computing apparatus that includes a detection apparatus for angular velocity and acceleration, a first posture angle computing unit, a low-pass filter, and a selecting unit that switches between two posture angles based on the machine's movement state, using complementary filters with different cutoff frequencies to reduce noise and stabilize posture angle detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the responsiveness upon detecting a posture angle is increased, then the work implement can be controlled to inhibit excavation beyond the boundary, but the detected posture angle changes in short cycles causing the position detection to swing
Solution Approach 1:
The system dynamically switches between two posture angle computing modes (first and second posture angle computing units) based on the detected change in angle. When the change exceeds a threshold, the system switches to the second computing unit with different filtering characteristics, allowing the system to adapt its responsiveness and stability characteristics according to the current operating conditions.
Solution Approach 2:
The system changes the filtering parameters (cutoff frequencies) of the posture angle computation based on the detected motion state. By adjusting the cutoff frequency parameter dynamically, the system can filter out short-cycle fluctuations during high-motion states while maintaining responsiveness during stable states, thus resolving the contradiction between speed and stability.
2Stability of the object's composition
If a low-pass filter is applied to stabilize posture angle detection, then position detection stability improves, but responsiveness to rapid posture changes is reduced
Solution Approach 1:
The system dynamically adjusts the filtering strength by switching between first and second posture angle computing units with different cutoff frequencies. During rapid posture changes, the system selects the computing unit with higher responsiveness, while during stable periods, it uses the unit with stronger filtering for enhanced stability.
Solution Approach 2:
The posture angle detection is divided into two separate computing paths (first and second posture angle computing units), each optimized for different operating conditions. The selecting unit segments the detection task by choosing the appropriate computing path based on the current motion state, allowing both stability and responsiveness to be optimized simultaneously.
Data Source
AI summary
A posture computing apparatus for a work machine includes a detection apparatus that is provided to the work machine and detects angular velocity and acceleration; a first posture angle computing unit that is provided to the detection apparatus and obtains a posture angle of the work machine from the angular velocity and the acceleration detected by the detection apparatus; a low-pass filter that allows the posture angle obtained by the first posture angle computing unit to pass therethrough to output the posture angle as a first posture angle; a second posture angle computing unit that outputs, as a second posture angle, a posture angle obtained from the angular velocity and the acceleration detected by the detection apparatus; and a selecting unit that outputs the first posture angle and the second posture angle in a switching manner, based on information about a change in an angle of the work machine.