Hydraulic Motor Valve Control for Pressure Shock and Jerking

Solution Overview

Problem

Hydraulic motors experience pressure shock and jerking due to their high rotational inertia, which existing control algorithms fail to reliably address, leading to inefficiencies and noise in hydraulic machine operations.

Innovation Solution

A novel valve control algorithm that differentiates the normalized flow factors for high pressure line and low pressure line valves (KvHP and KvLP) based on the operator's command, where KvLP < KvHP when 0 < Kvcmd < 1, to manage fluid flow and prevent sudden pressure changes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If a hydraulic motor is used as an actuator, then high power and rotational motion are achieved, but pressure shock and jerking occur due to high rotational inertia

Engineering Contradiction:

ImprovepowerVSAvoidpressure shock

Core Design Contradiction:

PowerVSObject-affected harmful factors

Solution Approach 1:

The control algorithm performs preliminary action by predicting the required valve flow factors KvHP and KvLP based on the commanded rotational speed, rather than reacting to pressure shocks after they occur. The algorithm calculates appropriate valve openings in advance to prevent pressure shocks during motor acceleration and deceleration.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The invention changes the parameters of the control system by introducing differentiated normalized flow factors KvHP and KvLP for the high-pressure and low-pressure line valves. These parameters are dynamically adjusted based on the commanded rotational speed to optimize fluid flow and prevent pressure shocks.

Inventive Principle:

Principle #35Parameter changes

2Power

If a hydraulic motor is used as an actuator, then high power and rotational motion are achieved, but jerking occurs during rotation start due to high rotational inertia

Engineering Contradiction:

ImprovepowerVSAvoidjerking

Core Design Contradiction:

PowerVSEase of operation

Solution Approach 1:

The control algorithm performs preliminary action by predicting the required valve flow factors KvHP and KvLP based on the commanded rotational speed, rather than reacting to pressure shocks after they occur. The algorithm calculates appropriate valve openings in advance to prevent pressure shocks during motor acceleration and deceleration.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The invention changes the parameters of the control system by introducing differentiated normalized flow factors KvHP and KvLP for the high-pressure and low-pressure line valves. These parameters are dynamically adjusted based on the commanded rotational speed to optimize fluid flow and prevent pressure shocks.

Inventive Principle:

Principle #35Parameter changes

3Device complexity

If conventional valve control is used, then system simplicity is maintained, but reliable control of hydraulic motor movement is not achieved

Engineering Contradiction:

Improvecontrol algorithmVSAvoidmovement control

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The control algorithm uses feedback by continuously monitoring the commanded rotational speed and adjusting the valve flow factors KvHP and KvLP accordingly. The algorithm incorporates feedback loops that respond to changes in motor speed commands to maintain reliable control throughout the motor's operation.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The invention changes the parameters of the control system by introducing differentiated normalized flow factors KvHP and KvLP for the high-pressure and low-pressure line valves. These parameters are dynamically adjusted based on the commanded rotational speed to optimize fluid flow and prevent pressure shocks.

Inventive Principle:

Principle #35Parameter changes

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 algorithm effectively reduces pressure shock and jerking by controlling fluid flow more precisely, enhancing the smooth operation and reducing noise in hydraulic machines.

Implementation Method 1

The control unit may control the high pressure line valve to have a normalized flow factor K vHP , and control the low pressure line valve to have a normalized flow factor K vLP

Methodology Applied

Scientific EffectFluid flow control through valve normalization: Valve

Data Source

PatentEP4166793A1Hydraulic machine and method of controlling the same

Publication Date: 2023.04.19 VOLVO CONSTRUCTION EQUIPMENT AB

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AI summary

A hydraulic machine. A high pressure line allows working fluid to flow into a hydraulic motor. A low pressure line allows working fluid to flow out of the hydraulic motor. High pressure line valves open and close the high pressure line. Low pressure line valves open and close the low pressure line. An operator input device inputs a command to control movement of the hydraulic motor. A control unit controls the high pressure line valves and the low pressure line valves to be opened and closed by receiving the command from the operator input device. The control unit controls the high pressure line valves to have a normalized flow factor KvHP, and controls the low pressure line valves to have a normalized flow factor KvLP, where KvLP<KvHP when a normalized flow factor Kvcmd corresponding to the command is 0<Kvcmd<1.