Hydraulic Shovel Calibration via Coordinate Transformation
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Solution Overview
Problem
The accuracy of position coordinates in hydraulic shovels is affected by errors in design parameters, making calibration time-consuming and burdensome, as precise measurement of multiple parameters is required to match computed and actual values.
Innovation Solution
A hydraulic shovel calibration system that includes a calibration device and an external measurement device, which computes calibration values by converting measured coordinates into a vehicle body coordinate system, reducing the need for direct parameter measurement and eliminating the need for iterative parameter rearrangement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If parameters are measured using a measurement means such as a measuring tape during initial settings, then position coordinates can be computed, but measurement accuracy is difficult to achieve and calibration time becomes extremely long
Solution Approach 1:
The patent replaces manual measurement methods (measuring tape) with an optical measurement system (laser tracker). The laser tracker automatically measures the three-dimensional coordinates of the working point, eliminating the need for manual parameter measurement and significantly reducing calibration time while improving accuracy.
Solution Approach 2:
The system enables self-calibration by automatically computing calibration values from the measured three-dimensional coordinates. The calibration device performs coordinate system transformation and calculates parameter corrections without requiring manual intervention or iterative adjustment, making the calibration process autonomous and efficient.
2Measurement precision
If multiple parameters are measured and input into the position detection device, then position detection accuracy can be improved, but the number of measurement steps increases and calibration becomes burdensome
Solution Approach 1:
The patent extracts only the essential parameters needed for calibration by measuring the three-dimensional coordinates of the working point directly. Instead of measuring multiple individual parameters (boom length, arm length, bucket length, angles), the system measures the final position coordinates and derives the necessary calibration information from these coordinates through coordinate system transformation.
Solution Approach 2:
The system changes the measurement approach from directly measuring physical parameters (lengths and angles of mechanical components) to measuring positional parameters (three-dimensional coordinates of the working point). This parameter transformation simplifies the measurement process and reduces the number of measurement steps required.
Data Source
AI summary
A current position computation unit of a hydraulic shovel computes a current position of a working point included in a work tool based on a plurality of parameters that indicate the dimensions and swing angles of a boom, an arm, and the work tool. A vehicle body coordinate system computation unit of a calibration device computes coordinate conversion information based on first and second working point position information measured by an external measurement device. A coordinate conversion unit converts coordinates at a plurality of positions of the working point measured by the external measurement device in a coordinate system of the external measurement device to those in a vehicle body coordinate system using the coordinate conversion information. A calibration computation unit computes calibration values of the parameters based on the converted coordinates at the plurality of positions of the working point in the vehicle body coordinate system.