Hydraulic Machine Torque Oscillation Control
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Solution Overview
Problem
Hydraulic machines with multiple cylinders face torque fluctuations and oscillations due to malfunctions in individual cylinders, leading to potential fatigue and noise issues, with existing technologies lacking a specific configuration to suppress these oscillations.
Innovation Solution
A hydraulic machine with a controller that switches the state of working chambers to non-active or reduces their active frequency, synchronizing with the reciprocating phase of abnormal chambers to maintain torque balance and reduce oscillations, using a state-switch unit with high-pressure and low-pressure valves to manage energy conversion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the hydraulic machine includes a plurality of cylinders to continue operation even if there is a trouble in a part of the cylinders, then the reliability is improved, but the torque fluctuation of the rotation shaft increases causing oscillation and noise
Solution Approach 1:
The controller detects malfunction of a cylinder before it causes severe torque fluctuation and oscillation. When malfunction is detected, the controller proactively switches the corresponding working chamber to a non-active state, preventing the torque imbalance from occurring in the first place. This preliminary action maintains both reliability (continuation of operation) and stability (torque balance).
Solution Approach 2:
The system changes the operational state parameter of the working chamber from active to non-active when cylinder malfunction is detected. This parameter change adjusts the torque contribution of the affected cylinder, compensating for the malfunction and maintaining overall torque balance, thereby suppressing oscillation and noise while keeping the system operational.
2Stability of the object's composition
If the working chamber is fixed to the non-active state to suppress torque fluctuation, then the oscillation is reduced, but the productivity decreases due to reduced number of active working chambers
Solution Approach 1:
The system extracts only the malfunctioning cylinder from the active working group by switching its working chamber to non-active state. The remaining healthy cylinders continue to operate and produce torque, maintaining productivity. This selective extraction prevents oscillation while preserving the operational capacity of the hydraulic machine.
Solution Approach 2:
The controller continuously monitors the operational state of each cylinder and provides feedback. When malfunction is detected, the controller adjusts the working chamber state accordingly. This feedback mechanism ensures that only necessary working chambers are deactivated, optimizing the balance between torque stability and productivity by making real-time adjustments based on actual system conditions.
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
The solution effectively suppresses torque fluctuations and oscillations, ensuring stable operation with reduced noise and extended lifespan of the rotation shaft by averaging torque and minimizing oscillation components.
Implementation Method 1
energy is converted between rotation energy of the rotation shaft and pressure energy in the working chamber
Data Source
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AI summary
A hydraulic machine includes a rotation shaft (22), a plurality of pistons (26) configured to reciprocate in a period corresponding to a single rotation of the rotation shaft (22), a plurality of cylinders (24) forming a plurality of working chambers (25) with the plurality of pistons (26), a state-switch unit for switching a state of each working chamber (25) between an active state in which energy is converted between rotation energy of the rotation shaft (22) and pressure energy in the working chamber (25) and a non-active state in which the energy is not converted, and a controller (50) for controlling the state-switch unit. The controller (50) is configured to fix a state of at least one of the working chambers (25) to the non-active state, the at least one working chamber corresponding to a time phase different from the time phase of reciprocation of the piston of an abnormal working chamber with a malfunction, or to reduce a frequency of switching the state of the at least one working chamber to the active state. The corresponding method of operating a hydraulic machine is also disclosed.