Excavator Payload Mass Estimation Using CAD-Based Load Parameters
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Solution Overview
Problem
Existing methods for estimating the load mass of excavated material by excavators require calibration runs and reference data, which are time-consuming and limit the accuracy of load mass estimation, especially when dealing with varying speeds and angular positions.
Innovation Solution
A system and method that utilize pre-configured CAD data for initializing system parameters, allowing for load mass estimation without the need for calibration runs, using a sensor system and control device to determine payload mass based on machine-status signals, force sensors, and predefined stimulation trajectories.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If model-based approaches with equations of motion are used for load-mass estimation, then measurement precision is improved, but device complexity increases due to requiring calibration runs and reference data
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing characteristic maps during the manufacturing process, before the excavator is delivered to the customer. These characteristic maps contain pre-configured system parameters that eliminate the need for on-site calibration runs. The control device simply retrieves and uses these pre-prepared parameters during operation, transforming a complex calibration procedure into a simple data lookup operation.
2Manufacturing precision
If characteristic maps are prepared for specific movements only, then manufacturing precision is improved, but adaptability decreases because differing speeds and angular positions distort estimation results
Solution Approach 1:
The patent achieves universality by creating characteristic maps that are valid across all operational conditions rather than for specific movements only. The system uses comprehensive pre-measured parameters that cover the entire working range of the excavator, allowing the same characteristic maps to accurately estimate load mass regardless of varying speeds, angular positions, or operational configurations. This multi-functional approach eliminates the need for multiple movement-specific calibration sets.
Solution Approach 2:
The patent applies parameter changes by using pre-configured system parameters from CAD data that automatically adapt to different operational conditions. Instead of requiring recalibration for each movement type, the system modifies its estimation calculations based on real-time sensor inputs (speed, position, acceleration) while relying on the robust pre-established characteristic maps. This allows accurate estimation across varying operational parameters without sacrificing the precision achieved during manufacturing.
3Measurement precision
If calibration runs are required before load-mass estimation, then measurement precision is improved, but loss of time increases due to setup requirements
Solution Approach 1:
The patent eliminates time loss by performing all necessary calibration and parameter measurement during the manufacturing process, before the excavator is delivered to the customer. The characteristic maps are completely prepared in advance, and no additional calibration runs are needed during deployment. This preliminary action transforms a time-consuming field calibration procedure into an instantaneous parameter retrieval operation, maintaining measurement precision while eliminating time loss.
Data Source
AI summary
The present invention relates to a system for determining the mass of a payload moved by a working device of a machine, comprising:a lifting-gear element that is movable along a path and is designed to move the working device;a sensor system that is designed to provide a plurality of machine-status signals which indicate a status of the machine;a force sensor system that is designed to provide a lifting-force signal that indicates a force on the lifting-gear element; anda control device that is designed:to use system parameters for load determination that originate from pre-configured CAD data, preferably CAD data that has been pre-configured at the factory, and/or from continuous calibration of system parameters;to carry out calibration using the pre-configured parameters as initialisation if unsatisfactory results are achieved;to carry out the calibration in an unloaded state, i.e. when the working device is empty, with automatically predefined stimulation trajectories being used for the machine or instructions being provided to the operator for stimulating the parameters;to log the system statuses using the sensor and to carry out a system identification of this information; andto determine a mass of the payload on the basis of identified and/or pre-configured system parameters and system statuses, preferably on the basis of a position, a speed, an acceleration of the lifting-gear element and/or a force or torque on the lifting-gear element.