Electrohydraulic Valve Sensor Recalibration Using a Master Pressure Reference
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Solution Overview
Problem
Electro-hydraulic systems in work machines face sensor drift issues, leading to inaccurate flow control and system performance, which is difficult to recalibrate online due to the complexity and reliance on multiple sensors, making existing recalibration methods impractical in active work machines.
Innovation Solution
A method to identify and utilize a recalibration reference sensor within the hydraulic system by detecting sensor drift or faults, selecting a trusted master reference sensor, and calculating new gain and offset values for other sensors based on comparisons with the master sensor, allowing for online recalibration without requiring offline recalibration processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional offline recalibration methods are used, then sensor accuracy can be restored, but the system requires removal from service and specialized test equipment
Solution Approach 1:
The system performs self-calibration by using one functional pressure sensor as a reference to recalibrate other sensors in-place within the hydraulic system, eliminating the need for external test equipment and system removal. The control system automatically identifies a good sensor, compares readings, and adjusts calibration parameters for drift compensation.
Solution Approach 2:
The control system acts as an intermediary that facilitates the calibration process by comparing readings from multiple sensors, identifying a reference sensor with acceptable drift characteristics, and using that sensor as a mediator to establish calibration relationships for other sensors in the system.
2Adaptability or versatility
If multiple pressure sensors are used in the electro-hydraulic system, then system functionality and control performance are improved, but the complexity of recalibration increases
Solution Approach 1:
The calibration process is segmented into automated steps executed by the control system: identifying a reference sensor, comparing readings from all sensors against the reference, calculating drift compensation parameters, and applying calibration adjustments. This segmentation reduces the complexity burden from the operator to the automated system.
Solution Approach 2:
The system uses feedback from multiple pressure sensors to automatically determine which sensor has the least drift, then uses that sensor's readings as feedback to calibrate the other sensors. This feedback mechanism simplifies the recalibration process by eliminating manual intervention and complex procedural steps.
3Measurement precision
If sensor recalibration is performed offline, then accurate calibration can be achieved, but downtime and loss of productivity occur
Solution Approach 1:
The system continuously monitors pressure sensor readings during normal operation and accumulates data for drift analysis. When recalibration is needed, the preliminary work of data collection and reference sensor identification has already been completed, allowing rapid calibration execution without extended downtime.
Solution Approach 2:
The calibration process maintains continuity of useful action by performing recalibration in-place during system operation or with minimal interruption. The control system continuously uses pressure sensor data for both operational control and calibration purposes, eliminating the need to stop the system for calibration and maintaining uninterrupted productive operation.
Data Source
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AI summary
An online method for reconfiguring pressure and position sensors in a hydraulic system is disclosed. In one step, a sensor drift condition, a recalibration request, or an unisolated fault condition is detected. In another step, a system pressure sensor or another sensor, such as a load-sense pressure sensor, is verified as a trusted master reference sensor. Another step includes measuring and recording a first pressure reading at the master reference sensor and first voltage readings associated with first, second, third, and fourth pressure slave sensors at a first pump pressure set point. Another step includes, repeating the previous step at a second pump pressure set point. A new gain and offset for each of the first, second, third, and fourth pressure sensors can be calculated based on a comparison of the recoded first and second pressure readings and the recorded first and second voltage readings.