Hydraulic Actuator Pressure Calibration for Construction Machinery
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Solution Overview
Problem
Existing hydraulic systems in construction machines, such as hydraulic excavators, face inaccuracies in controlling hydraulic actuators due to errors in pressure and position sensors, leading to inconsistent flow rates and operation velocities.
Innovation Solution
A construction machine equipped with a hydraulic pump, supply and discharge lines, actuators, meter-in and meter-out valves, load-pressure sensors, and a controller that calculates and adjusts pressures using calibration maps to accurately calibrate sensor readings, ensuring precise control of hydraulic actuators.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If pressure sensors and position sensors are used to control hydraulic actuators, then the operation velocity and flow rate can be adjusted, but sensing errors cause inaccurate flow rate control and actuator operation
Solution Approach 1:
The patent applies preliminary action by performing calibration of pressure sensors before actual hydraulic operations. The calibration process establishes accurate pressure-value correspondence in advance, ensuring that subsequent measurements and control operations are based on precise sensor readings. This pre-calibration step eliminates sensing errors that would otherwise affect flow rate control and actuator operation accuracy.
2Measurement precision
If sensor calibration is performed to improve sensing precision, then accurate control is achieved, but the calibration process requires additional time and operational steps
Solution Approach 1:
The patent implements self-service calibration where the system automatically performs sensor calibration without requiring external intervention or complex calibration equipment. The control device autonomously adjusts the hydraulic actuator to predetermined positions and compares sensor readings with expected values, automatically correcting calibration deviations. This self-calibrating mechanism reduces calibration time and eliminates the need for manual calibration procedures.
3Productivity
If the flow rate through meter-in or meter-out valves is controlled based on pressure difference and valve opening, then actuator velocity is adjusted, but sensor errors cause inaccurate flow rate control
Solution Approach 1:
The patent applies feedback by continuously monitoring sensor readings and comparing them with predetermined reference values during calibration and operation. The control device receives feedback from pressure sensors and position sensors, automatically adjusts valve openings or pump output based on the feedback signal, and corrects deviations in real-time. This closed-loop feedback control ensures accurate flow rate control despite variations in system conditions or sensor drift.
Data Source
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AI summary
An object of the present invention is to provide a construction machine that allows easy and accurate calibration of a pressure sensor and enables accurate control of hydraulic actuators. A controller increases the delivery pressure of a hydraulic pump in a state in which first and second meter-out valves and a second meter-in valve are closed and in which a first meter-in valve is opened, and calibrates a first pressure-calculation map such that a pressure calculated on the basis of the first pressure-calculation map matches a pressure calculated on the basis of a supply-pressure-calculation map, and increases the delivery pressure of the hydraulic pump in a state in which the first and second meter-out valves and the first meter-in valve are closed and in which the second meter-in valve is opened, and calibrates a second pressure-calculation map such that a pressure calculated on the basis of the second pressure-calculation map matches the pressure calculated on the basis of the supply-pressure-calculation map.