Hydraulic Drive Source Resonance Control

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Solution Overview

Problem

Vibrations in working machines, such as wheel loaders, are caused by resonance frequency waves generated by hydraulic systems, leading to unwanted mechanical vibrations and pulsations.

Innovation Solution

Identifying the resonance frequency and controlling the drive source, typically an electric motor, to counteract these waves by adjusting its rotation speed and displacement, thereby reducing or eliminating vibrations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the hydraulic pump operates at certain speed and displacement to meet flow demands, then hydraulic fluid flow to working functions is maintained, but resonance frequency waves are generated causing unwanted vibrations

Engineering Contradiction:
Improvehydraulic fluid flowVSAvoidvibrations
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The invention dynamically adjusts the rotation speed of the hydraulic pump motor based on real-time detection of resonance frequency waves. The control system continuously monitors hydraulic system conditions and modifies motor speed to avoid operating at resonance frequencies, thereby eliminating vibrations while maintaining required hydraulic flow through compensatory speed adjustments.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention changes the operational parameters of the hydraulic pump by adjusting motor rotation speed away from resonance frequencies. The control system detects resonance conditions and modifies the speed parameter to counteract harmful vibrations, while maintaining sufficient hydraulic flow to meet working function demands.

Inventive Principle:
Principle #35Parameter changes

2Object-affected harmful factors

If the pump speed is adjusted to avoid resonance frequencies, then vibrations are reduced, but hydraulic fluid flow may be affected

Engineering Contradiction:
ImprovevibrationsVSAvoidhydraulic fluid flow
Core Design Contradiction:
Object-affected harmful factorsVSProductivity

Solution Approach 1:

The invention employs a feedback control system that continuously monitors both vibration levels and hydraulic flow requirements. When resonance frequency waves are detected, the system adjusts motor speed to eliminate vibrations while simultaneously monitoring hydraulic flow demands and making compensatory adjustments to maintain sufficient fluid supply to working functions.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The control system dynamically balances two competing requirements by continuously adjusting motor speed based on real-time conditions. It modulates speed to avoid resonance frequencies while compensating for flow variations to ensure hydraulic working functions receive adequate fluid, thereby resolving the contradiction between vibration reduction and productivity maintenance.

Inventive Principle:
Principle #15Dynamics

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 method effectively reduces or avoids unwanted vibrations in working machines by synchronizing the hydraulic pump's operation with the machine's resonance frequency, maintaining hydraulic fluid flow to the working function.

Implementation Method 1

identifying a resonance frequency for the working machine and controlling the drive source, preferably an electric motor, so as to counteract waves with the resonance frequency

Methodology Applied
Scientific EffectResonance: Resonance

Data Source

PatentEP2697441B1Method and device for reducing vibrations in a working machine
Publication Date: 2017.07.19 VOLVO CONSTRUCTION EQUIPMENT AB
  • EP2697441B1 patent drawingFigure 1
  • EP2697441B1 patent drawingFigure 2
  • EP2697441B1 patent drawingFigure 3

AI summary

The invention relates to a method for reducing vibrations in a working machine. The working machine comprises a hydraulic system with a hydraulic machine (102) for providing hydraulic fluid to at least one working function (105). The hydraulic machine is driven by a drive source (101) having a variable speed of rotation. The method comprises the steps of identifying a resonance frequency for the working machine, and controlling the drive source (101) so as to counteract waves with the resonance frequency.