Bell Crank Angle Calibration for Wheel Loader Boom
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Solution Overview
Problem
Existing methods for calibrating work machines, such as wheel loaders, struggle to accurately measure the bell crank angle in the actual operating angle region, leading to detection errors in the posture of the work implement.
Innovation Solution
A method for calibrating work machines that involves outputting detection values for the angle of the sub-link with respect to the boom in specified postures, converting these values into measurement angles, and calibrating the conversion values based on the relationship between the measurement angles and actual angles in the working tool postures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If calibration is performed using traditional methods, then the calibration process is simple, but the measurement precision of the bell crank angle in the actual operating angle region deteriorates
Solution Approach 1:
The patent performs preliminary actions by establishing a conversion value table that maps detection values to measurement angles before actual operation. This table is created by pre-calculating or pre-measuring the relationship between detection values and actual bell crank angles at multiple predetermined positions, allowing accurate measurement during normal operation without complex real-time calibration procedures.
Solution Approach 2:
The patent changes the parameter representation from raw detection values to converted measurement angles through the use of a conversion value table. By transforming the detection values into measurement angles that correspond to actual bell crank angles at multiple predetermined positions, the system achieves accurate measurement across the actual operating angle region while maintaining a relatively simple calibration structure.
2Reliability
If the bell crank angle is not accurately calibrated, then the device structure remains simple, but the reliability of work implement posture detection deteriorates
Solution Approach 1:
The patent performs preliminary calibration actions by creating a conversion value table that stores the relationship between detection values and actual bell crank angles at multiple predetermined positions. This pre-established table ensures reliable posture detection during normal operation, as the system can accurately convert detection values to measurement angles without requiring complex real-time adjustment mechanisms.
Solution Approach 2:
The patent creates a digital copy of the bell crank angle measurement system through the conversion value table, which stores predetermined relationships between detection values and actual angles. This copied information allows the system to reliably determine work implement posture by simply looking up conversion values rather than requiring complex physical measurement systems.
3Adaptability or versatility
If calibration is limited to predetermined positions, then the calibration process is simple, but the adaptability to actual operating conditions deteriorates
Solution Approach 1:
The patent performs preliminary calibration at multiple predetermined positions to create a conversion value table that covers the actual operating angle region. By pre-calculating or pre-measuring the relationship between detection values and actual angles at these predetermined positions, the system achieves adaptability to actual operating conditions without requiring complex real-time calibration during operation.
Solution Approach 2:
The patent changes the approach from single-point calibration to multi-point calibration by establishing conversion values at multiple predetermined positions. This allows the system to adapt to various actual operating angles by selecting appropriate conversion values from the table, achieving versatility without significantly increasing the complexity of the calibration method itself.
Data Source
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AI summary
The method for calibrating the wheel loader (1) includes steps (S12, S14), steps (S15), and steps (S16). In steps (S12, S14) detection voltages (V1', V2') for detecting the angle of the bell crank (18) with respect to the boom (14) in the predetermined posture of the boom (14) and bucket posture which are specified are output. In step (S15) the detection voltage (V1', V2') is converted as the bell crank angle (θ1', θ2') of the bell crank (18) with respect to the boom (14) based on the bell crank angle conversion table (T1). In step (S16) the conversion value is calibrated based on the relationship between the bell crank angle (θ1', θ2') and the bell crank angle (θ1, θ2) in the specified bucket posture.