Wheel Loader Load Weight Correction via Hydraulic Force Change Rate
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Solution Overview
Problem
Existing work machines, such as wheel loaders, face measurement errors when loading on inclined ground due to the influence of hydraulic pressure by inclination, which are not corrected by existing methods.
Innovation Solution
A work machine configuration that includes a lift arm, hydraulic actuator, hydraulic force detection, arm angle detection, and a controller to calculate the weight of a load by measuring hydraulic force and its change rate, correcting errors caused by inclination without requiring a detection unit for inclination angle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a detection unit for detecting inclination angle is provided, then measurement accuracy on inclined ground is improved, but device complexity increases
Solution Approach 1:
The system uses existing sensors (hydraulic force detection unit and arm angle detection unit) to self-detect inclination effects and automatically correct measurement errors through the controller, eliminating the need for separate inclination angle detection hardware
Solution Approach 2:
The controller acts as an intermediary that processes data from existing sensors and applies correction algorithms to compensate for inclination effects, achieving accurate measurement without direct inclination sensing
2Device complexity
If correction algorithms are applied using existing sensors, then device complexity is reduced, but measurement accuracy on inclined ground deteriorates
Solution Approach 1:
The system changes the parameters being measured (hydraulic force at multiple arm angles) and uses the relationships between these parameters to infer and correct for inclination effects, achieving accurate measurement without directly measuring inclination
3Measurement precision
If hydraulic force is measured at multiple rotation angles, then measurement accuracy is improved, but measurement time increases
Solution Approach 1:
The system measures hydraulic force at multiple arm rotation angles (excessive action beyond a single angle) to gather sufficient data for accurate inclination correction, accepting the time cost as necessary for achieving the desired measurement precision
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables accurate weight measurement on inclined surfaces without altering the existing component configuration, improving measurement accuracy by normalizing hydraulic force changes with respect to rotation angles.
Implementation Method 1
a hydraulic actuator configured to rotate the lift arm; a hydraulic force detection unit configured to detect a hydraulic force of the hydraulic actuator
Implementation Method 2
a hydraulic force detection unit configured to detect a hydraulic force of the hydraulic actuator
Implementation Method 3
an arm angle detection unit configured to detect a rotation angle of the lift arm
Implementation Method 4
a hydraulic-force-change-rate calculation unit configured to calculate a change rate of the hydraulic force with respect to the rotation angle of the lift arm as a hydraulic force change rate, and then calculate a new hydraulic force change rate by dividing the hydraulic force change rate by an average hydraulic force within the measurement angle range
Implementation Method 5
correct an error of the weight of the load occurring due to the inclination angle of the body on the basis of the new hydraulic force change rate calculated by the hydraulic-force-change-rate calculation unit
Data Source
AI summary
A wheel loader includes a lift arm, bucket, a lift cylinder that rotates the lift arm, a hydraulic force detection unit that detects a hydraulic force of the lift cylinder, an arm angle detection unit that detects a rotation angle of the lift arm, and a controller that calculates a weight of the load. A hydraulic force measurement unit measures a hydraulic force with the rotation angle of the lift arm within a predetermined measurement angle range; and a hydraulic-force-change-rate calculation unit calculates a change rate of the hydraulic force with respect to the rotation angle of the lift arm, and then calculates a new hydraulic force change rate within the measurement angle range. The controller corrects an error of the weight of the load occurring due to the inclination angle of the body on the basis of the new hydraulic force change rate calculated by the hydraulic-force-change-rate calculation unit.