Hydraulic Pump Pressure Pulsation Diagnosis Under Stable Actuation
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Solution Overview
Problem
Existing pump diagnostic techniques for construction machines, such as hydraulic excavators, face challenges in achieving precise and accurate diagnoses due to fluctuating load and rotational speed, which can lead to unstable acquisition of pressure frequency components.
Innovation Solution
A pump diagnostic device that includes an action instruction section, measurement condition setting section, calculation section, and anomaly determination section, which instructs the machine to perform specific actions, sets sampling conditions, calculates pressure pulsation amplitude, and determines anomalies based on measured pressure values, allowing for stable and accurate diagnosis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If frequency analysis of pressure is performed during normal operation, then diagnosis can be performed without separating the pump, but the diagnosis precision deteriorates due to unstable rotational speed and load changes
Solution Approach 1:
The system performs preliminary actions by instructing the hydraulic actuator to execute specific actions (lifting, lowering, holding) before diagnosis. This creates stable operating conditions with constant rotational speed and load, enabling accurate frequency analysis of pressure signals for diagnosing piston shoe friction.
Solution Approach 2:
The system dynamically adjusts the operating conditions by transitioning from normal variable load operation to controlled diagnostic actions. The hydraulic actuator is dynamically controlled to maintain constant rotational speed during diagnosis, stabilizing the pressure signal characteristics for accurate measurement.
2Measurement precision
If the hydraulic actuator performs specific diagnostic actions, then pressure measurement stability improves, but the diagnosis time increases
Solution Approach 1:
The system implements periodic diagnostic actions where the hydraulic actuator repeatedly performs lifting, lowering, and holding actions. This periodic operation creates consistent pressure pulsation patterns that can be analyzed over multiple cycles, improving measurement stability while keeping each diagnostic cycle relatively short.
Solution Approach 2:
The diagnostic process maintains continuous useful action by having the hydraulic actuator perform sequential actions (lifting → lowering → holding) without idle periods. This continuous operation generates sufficient data for accurate diagnosis while minimizing total diagnosis time.
Data Source
AI summary
Provided is a pump diagnostic device and construction machine capable of performing precise and accurate diagnosis. A diagnostic device 40 for a hydraulic pump 1 includes an action instruction section 42 that outputs an action instruction for causing a hydraulic actuator 29 of a hydraulic excavator 200 to perform a specific action, a measurement condition setting section 44 that sets a sampling condition in measurement of a pressure of the hydraulic pump 1 during the specific action, a calculation section 46 that acquires a measured value of the pressure sampled during the specific action under the set sampling condition, and calculates a pressure pulsation amplitude of the hydraulic pump 1, an anomaly determination section 47 that determines whether there is an anomaly in the hydraulic pump 1 based on the calculated pressure pulsation amplitude, and an output section 48 that outputs a determination result obtained by the anomaly determination section 47.