Work Machine Load Correction via Attitude-Based Controller
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Solution Overview
Problem
The existing methods for computing load values within a bucket in work machines, such as hydraulic excavators, are prone to errors due to the attitude of the work implement, as they rely on models that do not accurately represent the actual implement's position and operation.
Innovation Solution
A system and method that includes a controller for a work machine with a boom, arm, and bucket, which obtains reference and comparison load values based on different attitudes, generates correction data, and calculates a correction amount to correct the load value in real-time, reducing errors caused by the implement's attitude.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a balance equation model is used to compute load values, then the computation can be performed, but an error occurs between the actual work implement and the model due to the attitude of the work implement
Solution Approach 1:
The patent applies parameter changes by introducing correction amounts that adjust the computed load values based on the work implement's attitude parameters. The controller calculates correction amounts corresponding to different attitudes (e.g., bucket angles, arm angles) and applies these corrections to the load values computed from the balance equation, thereby compensating for model inaccuracies and improving measurement precision.
Solution Approach 2:
The patent replaces the purely mechanical balance equation model with a corrected computational model that incorporates attitude-based correction data. Instead of relying solely on the theoretical balance equation, the system substitutes in correction amounts derived from actual attitude measurements, effectively replacing the inadequate mechanical model with a more accurate computational approach.
2Device complexity
If the work implement attitude is not considered, then the computation is simpler, but the load value contains errors due to attitude variations
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing correction amounts for various work implement attitudes before actual operation. The controller has previously computed correction data based on the balance equation and different attitude configurations, storing these correction amounts for quick retrieval and application during operation, thus avoiding complex real-time calculations while maintaining accuracy.
Solution Approach 2:
The patent segments the load value computation into two distinct parts: the base computation from the balance equation and the attitude-based correction. By dividing the computation process into these separate segments, the system can maintain a relatively simple base calculation while applying targeted corrections only when attitude variations occur, balancing computational simplicity with measurement precision.
Data Source
AI summary
A controller obtains a load value within a bucket when a work implement has a basic attitude, as a reference value, and a load value, within the bucket when the work implement has an attitude different from the basic attitude, as a comparison value. The controller generates correction data according to an attitude of the work implement beforehand, based on the reference value and the comparison value. The controller senses a current attitude of the work implement, and calculates a correction amount of a load value within the bucket when the work implement has the current attitude, based on the correction data. The controller corrects a load value within the bucket when the work implement has the current attitude using the correction amount, and obtains a corrected load value.