Hydraulic Pump Current Calibration for Minimum Displacement Control
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Solution Overview
Problem
Hydraulic pumps with displacement increasing in accordance with command current face challenges in precisely setting minimum-use displacement or delivery flow rate due to individual differences in I-q characteristics, leading to deviations from intended settings.
Innovation Solution
Control circuitry that receives actual measurement data to determine a minimum-use electric current, allowing for precise setting of hydraulic pump displacement or delivery flow rate, utilizing a symbol on the pump to store measurement data and a mobile terminal for wireless data input.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If minimum-use electric current is determined based on design performance characteristics, then the pump can be controlled to achieve minimum-use displacement, but the actual minimum-use displacement deviates from the intended value due to individual differences in I-q characteristics
Solution Approach 1:
The patent applies preliminary action by pre-measuring and storing the actual I-q characteristics of each pump in a storage unit before the pump is put into service. This preliminary measurement allows the control system to later calculate the accurate minimum-use electric current based on the pump's actual characteristics rather than relying on design specifications that do not account for individual variations.
Solution Approach 2:
The patent implements feedback by using the stored actual I-q characteristics to continuously adjust and determine the minimum-use electric current. The control circuitry references the actual measurement data to calculate the precise current value needed to achieve the intended minimum-use displacement, creating a closed-loop system that compensates for individual pump variations.
2Adaptability or versatility
If a hydraulic pump is designed to be usable in different machines with different minimum displacement requirements, then the pump's adaptability increases, but individual differences in I-q characteristics cause deviations in minimum-use displacement settings across different applications
Solution Approach 1:
The patent applies self-service by enabling each pump to characterize itself through preliminary measurement of its actual I-q characteristics. The pump's unique identity and performance characteristics are stored in its own storage unit, allowing it to self-adjust and determine the correct minimum-use electric current for its specific application without requiring external calibration or adjustment for each machine it serves.
Solution Approach 2:
The patent utilizes parameter changes by storing and utilizing the actual I-q characteristic parameters of each individual pump. By basing the minimum-use electric current calculation on these actual measured parameters rather than design specifications, the system adapts to each pump's unique characteristics while maintaining consistent minimum-use displacement settings across different machines and applications.
Data Source
AI summary
Control circuitry feeds a command current to a hydraulic pump whose displacement increases in accordance with increase in the command current. The displacement of the hydraulic pump is a delivery amount per rotation of the hydraulic pump. The control circuitry receives an input of actual measurement data, the data either indicating an actual relationship between the command current and the displacement of the hydraulic pump or indicating a predetermined rotation speed and an actual relationship between the command current and a delivery flow rate of the hydraulic pump at the predetermined rotation speed; and receives an input of a minimum-use displacement of the hydraulic pump or a minimum-use delivery flow rate of the hydraulic pump at a reference rotation speed. The control circuitry determines a minimum-use electric current by using the actual measurement data, the minimum-use electric current corresponding to the minimum-use displacement or the minimum-use delivery flow rate.