Work Implement Calibration for Stable Machine Guidance Accuracy
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Solution Overview
Problem
Existing construction machines face challenges in accurately calibrating machine guidance and control systems due to variations in the posture of the work implement caused by factors such as hydraulic fluid changes and terrain conditions, leading to inaccurate calculation of mounting angles and link lengths.
Innovation Solution
A construction machine equipped with posture sensors and a controller that determines the static determinacy of the work implement during calibration, using conversion parameters to update the posture data into coordinates, ensuring accurate calibration by stabilizing the implement's posture during the calibration process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If calibration is performed using sequential coordinate acquisition with a total station, then mounting angles can be calculated, but posture variations during measurement cause inaccurate calibration results
Solution Approach 1:
The system performs preliminary detection of work implement posture using IMU sensors before calibration begins, and continuously monitors posture during the calibration process. This preliminary and continuous monitoring enables the system to detect posture variations in real-time and determine whether calibration data should be accepted or rejected, ensuring accurate calibration results even when posture changes occur during measurement.
2Manufacturing precision
If multiple coordinate points are acquired sequentially for calibration, then complete calibration data can be obtained, but time consumption increases and posture stability decreases
Solution Approach 1:
The system implements feedback by continuously monitoring work implement posture during calibration using IMU sensors and comparing it against initial posture readings. When posture variations exceed predetermined thresholds, the system provides feedback to reject the calibration data and request re-measurement, ensuring that only calibration data obtained during stable posture conditions is accepted, thereby maintaining high calibration accuracy without requiring excessively long measurement times.
3Ease of operation
If IMU sensors are used for posture detection, then responsiveness and ease of installation are improved, but accuracy of tilt angle measurement decreases compared to external measuring apparatus
Solution Approach 1:
The system uses the IMU sensor's own capabilities to detect work implement posture and provides self-verification by comparing sequential posture readings. The IMU sensor continuously monitors posture during calibration, and the system automatically determines whether posture variations are within acceptable ranges. This self-service approach allows the simpler IMU sensor to achieve calibration accuracy comparable to more complex external measuring apparatus while maintaining ease of installation.
Data Source
AI summary
It is an object of the present invention to provide a construction machine that is capable of increasing the accuracy with which to calibrate a machine guidance system or a machine control system. To achieve the object, a controller determines whether a work implement is statically determinate or not on the basis of posture data of the work implement sensed by a posture sensor during a predetermined time after an instruction has been given to calibrate conversion parameters (a mounting angle and a link length) for converting the posture data of the work implement into the coordinates of a first predetermined position (bucket claw tip position) of the work implement, and, when determining that the work implement is statically determinate, calculates updated values of the conversion parameters on the basis the posture data of the work implement sensed by the posture sensor during the predetermined time and the coordinates of a second predetermined position (pin position) of the work implement measured by an external measuring device after the instruction has been given to calibrate the conversion parameters.