Work Machine Load Mass Estimation via Actuator Thrust
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Solution Overview
Problem
Existing methods for estimating loaded weight in work machines, such as wheel loaders, are inaccurate when loads with weights outside predefined lists are encountered, as they fail to account for varying boom and bucket angles and cylinder forces.
Innovation Solution
A work machine system comprising a machine main body, a boom, a bucket, a first actuator for driving the boom, a second actuator for driving the bucket, and a controller that calculates the load mass based on the thrust of both actuators, incorporating sensors for boom and bucket angle measurements and cylinder pressures to generate a moment balance expression.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a predefined list relating boom angle and bottom pressure is used to estimate loaded weight, then the estimation method is simple, but the accuracy deteriorates when loads with weights outside the predefined list are encountered
Solution Approach 1:
The invention changes the parameters used for estimation from a simplified boom angle-bottom pressure relationship to a comprehensive model incorporating boom angle, bucket angle, first actuator thrust, and second actuator thrust. This multi-parameter approach dynamically adapts to any load weight within the measurement range, resolving the contradiction by maintaining simplicity through automated calculation while achieving high accuracy across all load conditions.
Solution Approach 2:
The invention transitions from a static predefined list to a dynamic estimation system that continuously calculates load mass based on real-time actuator thrusts and angles. The controller dynamically adjusts the estimation according to actual operating conditions, enabling accurate measurement for any load weight rather than relying on predetermined discrete values.
2Device complexity
If only boom angle and bottom pressure are used for estimation, then the measurement system is simple, but the accuracy deteriorates due to unaccounted variations in bucket angle and cylinder forces
Solution Approach 1:
The invention creates a universal estimation system that accounts for all significant mechanical parameters (boom angle, bucket angle, first actuator thrust, second actuator thrust) simultaneously. This multi-functional approach ensures accurate load mass estimation regardless of variations in any individual parameter, making the system universally applicable across all operating conditions while maintaining logical simplicity through centralized controller calculation.
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
This solution allows for accurate estimation of load mass within the bucket across various angles and positions, improving accuracy and eliminating the need for calibration corrections, even when the bucket's position relative to the boom varies.
Implementation Method 1
The controller calculates a mass of a load within the bucket based on thrust of the first actuator and thrust of the second actuator
Implementation Method 2
generators a moment balance expression... A mass of a load within the bucket is calculated based on the information on thrust of the first actuator and the information on thrust of the second actuator
Data Source
AI summary
A boom is attached to a machine main body. A bucket is attached to the boom. A boom cylinder is attached to the machine main body and drives the boom. A bucket cylinder is attached to the machine main body and drives the bucket with respect to the boom. A controller calculates a mass of a load within the bucket based on boom cylinder force and bucket cylinder force.