Mast Vibration Compensation in Industrial Trucks

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Solution Overview

Problem

Industrial trucks, such as reach trucks and counterbalanced forklifts, experience disruptive vibrations in the mast during operation, particularly when the mast is extended upwards, which can interfere with the precise placement of loads.

Innovation Solution

The implementation of sensors, including strain gauges, acceleration sensors, and gyroscope sensors, to detect mast vibrations, coupled with an electronic control device that adjusts the actuator's movement to counteract these oscillations, taking into account various operating parameters like position, speed, and load weight, to generate a compensating movement that minimizes mast vibrations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If the mast is extended upwards to increase lifting height, then the lifting capability is improved, but mast vibrations increase in amplitude

Engineering Contradiction:
Improvelifting heightVSAvoidmast vibration amplitude
Core Design Contradiction:
Length of moving objectVSStability of the object's composition

Solution Approach 1:

The system uses sensors (strain gauges, acceleration sensors, or gyroscope sensors) to detect mast vibrations in real-time and feeds this information back to the electronic control device. The control device then adjusts the actuator's movement based on this feedback to counteract the vibrations, allowing the mast to be extended to greater heights while maintaining stability through continuous monitoring and adjustment.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The electronic control device changes the movement parameters of the actuator dynamically based on the detected vibration conditions. By adjusting parameters such as movement speed, acceleration, and positioning based on real-time vibration data, the system can extend the mast to increased heights while actively compensating for vibration amplification that occurs at extended lengths.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If the actuator moves the mast quickly to improve productivity, then the lifting speed is improved, but mast vibrations are stimulated

Engineering Contradiction:
Improvelifting speedVSAvoidmast oscillation
Core Design Contradiction:
ProductivityVSStability of the object's composition

Solution Approach 1:

The sensor system continuously monitors mast vibrations during actuator operation and provides real-time feedback to the electronic control device. This allows the system to detect oscillations stimulated by quick movements and immediately adjust the actuator's movement to counteract these vibrations, maintaining high productivity while preventing harmful oscillations through active feedback control.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The electronic control device generates periodic compensating movements that counteract the oscillations stimulated by rapid mast movement. By applying periodic counter-vibrations at the same frequency as the detected oscillations, the system can maintain high lifting speeds while canceling out the harmful periodic vibrations through active vibration cancellation.

Inventive Principle:
Principle #19Periodic action

3Stability of the object's composition

If sensors and electronic control devices are added to detect and counteract vibrations, then mast stability is improved, but device complexity increases

Engineering Contradiction:
Improvemast vibration reductionVSAvoidsensor and control system
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The system replaces complex mechanical vibration damping mechanisms with an electronic control system that uses sensors and software-based compensation. Instead of adding heavy mechanical dampers or complex mechanical linkages, the invention uses electronic sensors to detect vibrations and software algorithms to calculate compensating movements, achieving vibration reduction through intelligence rather than mechanical complexity.

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

Solution Approach 2:

The system uses the existing actuator that is already part of the mast mechanism to perform the vibration compensation function. Rather than adding a separate dedicated vibration control mechanism, the system makes the existing actuator serve dual purposes: normal mast movement and vibration compensation. This reduces overall system complexity by utilizing existing components for multiple functions.

Inventive Principle:
Principle #25Self-service

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

This solution effectively reduces or eliminates mast vibrations, ensuring more stable operation and precise load placement by actively compensating for oscillatory movements based on real-time feedback and adaptive control algorithms.

Implementation Method 1

The strain gauge (DMS) is attached to a non-extendable fixed mast of the mast. It records the slight elastic changes in length of the stationary mast caused by the vibrations of the mast.

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

The acceleration sensor directly measures the acceleration of the free end of the mast caused by the vibration movement.

Methodology Applied
Scientific EffectAcceleration: Accelerometer

Implementation Method 3

the gyroscope sensor measures the change in the absolute angular position of the free end of the mast during the oscillation movement.

Methodology Applied
Scientific EffectGyroscope effect: Gyroscope

Data Source

PatentEP1975114B2Oscillation compensation for the lifting frame of an industrial truck
Publication Date: 2021.03.17 STILL GMBH
  • EP1975114B2 patent drawingFigure 1

AI summary

A sensor (10) recognizes the flexible sway in lifting equipment (4) that maintains an active link to an electronic control device for triggering a final control element (9) so as to move the lifting equipment in such a way that movement in the final control element causes a reaction to swaying in the lifting equipment, which is moved with the final control element in a horizontal direction.