Hydraulic Regeneration Control Under Pressure Sensor Abnormalities
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Solution Overview
Problem
Hydraulic drive systems for work machines, such as hydraulic excavators, face issues where abnormalities in pressure sensors can lead to unexpected operations of hydraulic actuators due to incorrect regeneration of hydraulic fluid, causing operational irregularities and reduced operability.
Innovation Solution
A hydraulic drive system with a controller that includes abnormality detection to prevent regeneration when sensor abnormalities are detected, ensuring that hydraulic fluid is not supplied to actuators even if measured values satisfy regenerative conditions, and adjusting the hydraulic pump flow rate based on sensor integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If regeneration control is performed based on sensor measurements, then energy recovery efficiency is improved, but system reliability deteriorates when sensor abnormalities occur
Solution Approach 1:
The system continuously monitors sensor outputs and compares them against expected operational ranges. When sensor readings fall outside normal parameters or show abnormal patterns, the feedback mechanism triggers an automatic switch from sensor-based regeneration control to operation-device-based control, ensuring reliable operation despite sensor failures
Solution Approach 2:
The control system dynamically changes the control parameter source based on system state. Under normal conditions, regeneration is controlled by pressure sensor measurements. When abnormalities are detected, the system switches to using operation device signals as the control parameter, maintaining functional reliability while preserving energy recovery capability
2Productivity
If the regenerative valve is opened based on sensor readings, then hydraulic fluid regeneration is improved, but unexpected actuator operation occurs when sensors are abnormal
Solution Approach 1:
The controller acts as an intermediary between sensors and the regenerative valve. It processes sensor signals, validates their合理性, and only permits valve operation when both sensor data and operation device signals are consistent. This intermediary function prevents abnormal sensor readings from causing unexpected actuator movement
Solution Approach 2:
The system performs preliminary validation of sensor readings before allowing regeneration-based actuator operation. By checking whether sensor measurements correspond to actual operation device states in advance, the system prevents unintended regeneration and maintains predictable actuator behavior
3Loss of energy
If passage to tank is throttled to reduce bleed flow rate, then regeneration efficiency is improved, but actuator deceleration or stopping occurs when pressure conditions are abnormal
Solution Approach 1:
The system uses feedback from pressure sensors to continuously monitor the pressure differential across the regenerative valve. When abnormal pressure conditions are detected (such as reverse pressure differential), the feedback mechanism automatically adjusts or closes the regenerative valve, preventing actuator deceleration while maintaining efficient bleed-off control under normal conditions
Solution Approach 2:
The regenerative valve control is made dynamic rather than fixed. The valve opening degree is continuously adjusted based on real-time pressure conditions and operation state. This dynamic control allows the system to optimize bleed-off reduction during normal operation while automatically adapting to prevent unwanted deceleration when pressure conditions change abnormally
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
Ensures that the operation of hydraulic actuators matches the operator's intentions even with sensor abnormalities, maintaining consistent and predictable performance by preventing unintended regeneration and flow rate changes.
Implementation Method 1
a hydraulic pump configured to supply hydraulic fluid to a work device and to a hydraulic actuator
Implementation Method 2
a regenerative device configured to supply the hydraulic fluid returning from the first hydraulic actuator to the second hydraulic actuator
Data Source
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AI summary
A hydraulic drive system 100A for a work machine includes: a boom cylinder 4; an arm cylinder 8; a hydraulic pump device 51; a control valve 5; a regenerative device 61; a first operation device 41; a second operation device 42; a sensor device 71; and a controller 27. The sensor device 71 includes at least one of pressure sensors 23, 24, 25, and 26. The controller 27 includes an abnormality detection part 142 and a first control part. The abnormality detection part 142 determines whether or not the sensor device 71 is abnormal. If the sensor device 71 is abnormal, the first control part controls the regenerative device 61 such that the hydraulic fluid returning from the boom cylinder 4 is not supplied to the arm cylinder 8 even if the values measured by the sensor device 71 satisfy regenerative conditions.