Excavator Calibration Device Using Segmented Actuator Adjustment
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Solution Overview
Problem
Existing calibration methods for hydraulic excavators face challenges in accurately estimating the position of the blade edge of the bucket due to inevitable errors between calibrated working equipment parameters and true values, especially when the blade edge is in attitudes other than those used for calibration, leading to poor estimation accuracy.
Innovation Solution
A calibration device and method that includes first and second actuation units with respective swing angle detectors, an attitude calculating unit, and an estimated position calculating unit, which acquires and calibrates working equipment parameters using external measurement values to reduce errors and improve accuracy, particularly by calibrating the first actuation unit parameters first to enhance the calibration of the second actuation unit parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If all working equipment parameters are calibrated based on the position of the blade edge of the bucket, then the calibration process is simplified, but the accuracy of the calibrated parameters deteriorates due to inevitable errors between calibrated values and true values
Solution Approach 1:
The calibration process is divided into two independent stages: first calibrating the boom (first actuation unit) parameters using measurements from the boom pin, then calibrating the bucket (second actuation unit) parameters using measurements from the bucket pin. This segmentation allows each calibration stage to focus on specific parameters, reducing cumulative errors and improving overall accuracy while maintaining process simplicity.
Solution Approach 2:
The boom parameters are calibrated in advance before bucket parameter calibration. By completing the first actuation unit calibration first, the system establishes an accurate reference frame that reduces errors in subsequent bucket calibration, thereby improving the accuracy of final blade edge position estimation.
2Ease of manufacture
If calibration is performed only at specific attitudes, then the calibration process is simplified, but the estimation accuracy deteriorates when the blade edge is in attitudes other than calibration attitudes
Solution Approach 1:
The system performs separate calibrations for the boom and bucket at their respective reference attitudes (boom horizontal, bucket vertical). This segmented approach allows each component to be calibrated at its optimal reference position, ensuring high accuracy while keeping the calibration process simple and manageable.
Solution Approach 2:
The system uses swing angle information from detectors to dynamically calculate the actual attitude of each actuation unit during operation. By combining calibrated parameters with real-time attitude data, the system maintains high estimation accuracy across all operating attitudes, not just calibration attitudes.
3Measurement precision
If multiple measurement points are used for calibration, then the calibration accuracy is improved, but the complexity of the calibration process increases
Solution Approach 1:
The system extracts and uses specific key measurement points (boom pin and bucket pin) for calibration, rather than requiring multiple measurement points across the entire working equipment. This extraction of essential measurement locations simplifies the calibration process while maintaining high accuracy through the sequential calibration approach.
Data Source
AI summary
A calibration device for a work machine includes: a working equipment parameter acquiring unit acquiring working equipment parameters of members of first and second actuation units; a measurement value acquiring unit acquiring respective measurement values of the work machine body and first and second actuation units measured by an external measurement device; a first calibration unit calibrating the parameter related to the member of the first actuation unit acquired by the acquiring unit based on the measurement value of the first actuation unit acquired by the acquiring unit; and a second calibration unit calibrating the working equipment parameter of the member of the second actuation unit based on the working equipment parameter of the first actuation unit calibrated by the first calibration unit and the respective measurement values of the reference points of the work machine body and first and second actuation units acquired by the acquiring unit.