Compaction Machine Steering Feedback for Hydraulic Stroke Limits

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Solution Overview

Problem

Vibratory trench rollers lack feedback on their direction of travel and hydraulic cylinder stroke limits, leading to inefficient operation and strain on the hydraulic system due to excessive hydraulic flow.

Innovation Solution

A compaction machine with a steering angle sensor and control unit that provides feedback on the machine's steering angle and hydraulic cylinder stroke, overriding commands that exceed limits and automatically returning to a neutral position when no steering command is given.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If remote control is used to operate the trench roller, then operator safety is improved, but the operator loses direct feedback on machine direction and hydraulic cylinder stroke limits

Engineering Contradiction:
Improveoperator safetyVSAvoidfeedback on machine direction and stroke limits
Core Design Contradiction:
ReliabilityVSLoss of information

Solution Approach 1:

The patent implements feedback by equipping the trench roller with a steering angle sensor that continuously monitors the actual steering angle and transmits this information back to the remote control unit. This allows the operator to see the actual machine direction and hydraulic cylinder stroke position on the remote control display, providing real-time feedback without requiring the operator to be physically present on the machine.

Inventive Principle:
Principle #23Feedback

2Ease of operation

If the hydraulic cylinder is allowed to extend beyond its stroke limit, then steering control flexibility is improved, but hydraulic system strain and power loss increase

Engineering Contradiction:
Improvesteering control flexibilityVSAvoidhydraulic power consumption
Core Design Contradiction:
Ease of operationVSUse of energy by moving object

Solution Approach 1:

The control unit receives feedback from the steering angle sensor about the actual steering angle and hydraulic cylinder position. When the steering angle approaches the maximum limit corresponding to full hydraulic cylinder extension, the system provides visual feedback to the operator and can automatically prevent further extension commands, thereby avoiding excessive hydraulic flow through the relief valve and reducing power consumption.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system proactively monitors the steering angle and predicts when the hydraulic cylinder will reach its stroke limit. By providing advance warning to the operator through visual feedback before the limit is reached, the system prevents the operator from issuing commands that would cause excessive hydraulic strain, thus reducing power consumption before the problem occurs.

Inventive Principle:
Principle #10Preliminary action

3Device complexity

If the articulated trench roller continues at the last commanded angle without feedback, then steering simplicity is maintained, but operational precision deteriorates

Engineering Contradiction:
Improvesteering control simplicityVSAvoidsteering angle precision
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The steering angle sensor provides continuous feedback on the actual steering angle to the control unit, which then displays this information on the remote control. This allows the operator to see the precise machine direction and make accurate adjustments to achieve the desired steering angle, significantly improving operational precision while maintaining remote control simplicity.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP4311878B1Compaction machine steering system
Publication Date: 2025.09.03 WACKER NEUSON CORP
  • EP4311878B1 patent drawingFigure 1
  • EP4311878B1 patent drawingFigure 2
  • EP4311878B1 patent drawingFigure 3

AI summary

A compaction machine system includes a compaction machine in communication with a remote control. The compaction machine includes a mobile chassis with a first and second subframes pivotably connected at a pivot connection, a steering angle sensor, a steering actuator for causing the first and second subframes to pivot, and a control unit in communication with the steering angle sensor and with the steering actuator. The control unit determines an operational stroke of the of the steering actuator and controls the steering actuator based on the input from the direction control and the determined operational stroke of the steering actuator. When the steering actuator is at a limit of its operational stroke, the control unit overrides commands from the direction control that otherwise would result in extending or retracting the steering actuator stroke beyond its operational limit. The control unit also returns the steering actuator to its neutral position in the absence of an operator-generated steering command.