Dual Eccentric Shaft Synchronization for Low-Noise Vibratory Compaction

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Solution Overview

Problem

Vibratory compaction machines generate noise and vibrations due to the relative position of eccentric shafts, which are difficult to control effectively, leading to environmental disturbances.

Innovation Solution

A computer system that calculates and controls the quadrature currents of lead and follower motors to synchronize the rotation speeds and phase angles of the eccentric shafts, using closed-loop control to adjust the phase angle to target values, thereby reducing noise and improving position control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If the rotation speed and phase angle of eccentric shafts are not synchronized, then the compaction efficiency is improved through independent operation, but noise and vibration disturbances increase significantly

Engineering Contradiction:
Improvenoise and vibration disturbancesVSAvoidcontrol system complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent implements a feedback control system that continuously monitors the rotation speeds and phase angles of the eccentric shafts and adjusts them in real-time. The control system receives signals from sensors detecting shaft positions and modifies motor commands to maintain synchronization, thereby reducing noise and vibration while managing system complexity through automated closed-loop control.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent changes operational parameters (rotation speed and phase angle) dynamically to achieve synchronization. By adjusting these parameters in real-time based on detected shaft positions, the system reduces harmful noise and vibration effects while maintaining compaction efficiency, resolving the contradiction between performance and harmful factors.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If the phase angle between lead and follower motors is not controlled, then the operation is simpler, but the position control accuracy of eccentric shafts deteriorates

Engineering Contradiction:
Improveposition control accuracyVSAvoidoperation simplicity
Core Design Contradiction:
Manufacturing precisionVSEase of operation

Solution Approach 1:

The patent replaces complex mechanical synchronization mechanisms with an electronic control system that uses sensors and processors to detect and adjust phase angles. This substitution achieves high position control accuracy through electronic feedback while maintaining operational simplicity by automating the synchronization process, eliminating the need for manual mechanical adjustments.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Manufacturing precision

If closed-loop control is used to synchronize rotation speeds, then the position control accuracy is improved, but the response time and system complexity increase

Engineering Contradiction:
Improveposition control accuracyVSAvoidresponse time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent implements preliminary synchronization actions by pre-establishing target phase angles and rotation speed relationships between lead and follower motors. The control system prepares synchronization parameters in advance and executes adjustments more rapidly, reducing response time while maintaining high position control accuracy through pre-configured control strategies.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP4380037A1Computer system for detecting and controlling a relative position of two rotating eccentric shafts, vehicle comprising such a computer system, method, and storage medium for performing such a method
Publication Date: 2024.06.05 VOLVO CONSTRUCTION EQUIPMENT AB
  • EP4380037A1 patent drawingFigure 1
  • EP4380037A1 patent drawingFigure 2
  • EP4380037A1 patent drawingFigure 3

AI summary

A computer system (80) for detecting and controlling a relative position of two rotating eccentric shafts (50, 60), comprising processing circuitry (82) configured to: calculate a lead motor quadrature current of a lead motor (30) driving a first eccentric shaft (50); calculate a follower motor quadrature current of a follower motor (40) driving a second eccentric shaft (60); determine in real-time a phase angle between the lead motor and follower motor quadrature currents; modify a rotation speed of the follower motor (40) so that it is equal to a rotation speed of the leading motor (30); and when the rotation speed of the follower motor (40) is equal to the rotation speed of the lead motor (30), modify the rotation speed of the follower motor (40) to adjust the phase angle to be equal to a main target phase angle.