Hydraulic Actuator Weight Determination via Threshold Pressure

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Solution Overview

Problem

Current methods for determining the weight of a load using hydraulic or pneumatic actuators are time-consuming and prone to errors due to variations in speed and friction, making them impractical for speedy and precise weight determination, especially in unstable load conditions or dosage weighing applications.

Innovation Solution

The method involves determining an intermediate pressure based on actuator motion pressure, which is used as a reference to quickly adjust the actuator pressure to threshold values, eliminating the need for time-consuming fine-adjustments and cycles of pressure measurement, thereby reducing idle time and improving precision.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the actuator pressure is adjusted slowly with frequent measurements to determine threshold pressures precisely, then measurement precision is improved, but the time required for weight determination increases

Engineering Contradiction:
Improveprecision in determination of threshold pressure valuesVSAvoidtime required for weight determination
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent applies preliminary action by determining an intermediate pressure value during the initial lifting phase, before the actual threshold pressure measurement begins. This intermediate value serves as a predetermined reference point that eliminates the need for time-consuming pressure adjustments and measurements during the subsequent threshold determination phases. By performing this preparatory measurement beforehand, the system achieves both high precision in threshold pressure determination and reduced overall measurement time.

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If dynamic measuring is used to eliminate friction and acceleration errors, then measurement precision is improved, but the complexity of the measuring process increases

Engineering Contradiction:
Improveweight determination accuracyVSAvoidcomplexity of measuring process
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts and eliminates the harmful effects of friction and acceleration errors by using a static measurement method. Instead of attempting to measure during motion (which would require complex speed control and synchronization systems), the invention takes out these dynamic error sources entirely by performing measurements in the static state before and after lifting. This extraction of the problematic dynamic elements simplifies the measuring process while maintaining precision.

Inventive Principle:
Principle #2Taking out (Extraction)

3Measurement precision

If the load is moved a great distance up for dynamic measuring, then measurement precision is improved by eliminating friction effects, but productivity decreases

Engineering Contradiction:
Improveweight determination accuracyVSAvoidspeed of weight determination
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent applies the skipping principle by eliminating the need to move the load a great distance for measurement purposes. Instead of performing lengthy dynamic measurement cycles, the invention rushes through the measurement process by taking snapshots of pressure values in the static state immediately before lifting begins and immediately after lifting completes. This skipping of the lengthy motion phase maintains measurement precision while dramatically reducing the time required.

Inventive Principle:
Principle #21Skipping (Rushing through)

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 approach significantly reduces the time required for weight determination while maintaining precision, as the actuator pressure is regulated directly to the intermediate pressure after the first threshold is determined, allowing for faster and more efficient weight calculation.

Implementation Method 1

a method for determining the weight of a load using a hydraulic or pneumatic actuator of a lifting mechanism

Methodology Applied
Scientific EffectHydraulic pressure: Hydraulic Press

Implementation Method 2

static friction of the lifting mechanism is no longer able to maintain the position of the load

Methodology Applied
Scientific EffectStatic friction: Static Friction

Data Source

PatentEP3011282B1A method and a device for determining the weight of a load
Publication Date: 2021.02.17 GRIPTECH
  • EP3011282B1 patent drawingFigure 1
  • EP3011282B1 patent drawingFigure 2
  • EP3011282B1 patent drawingFigure 3

AI summary

The invention relates to a method for determining the weight of a load using a hydraulic or pneumatic actuator (2) of a lifting mechanism, com- prising the steps of increasing the actuator pressure to an initial value, in which static friction of the lifting mechanism is no longer able to maintain the position of the load, maintaining an actuator motion pressure until the load is lifted to a desired suspended position, adjusting the actuator pressure to a first threshold pressure, in which static friction of the lifting mechanism is no longer able to maintain the position of the load, determining a first threshold pressure value for the first threshold pressure, adjusting the actuator pressure to a second threshold pressure, in which static friction of the lifting mecha- nism is no longer able to maintain the position of the load, determining a sec- ond threshold pressure value for the second threshold pressure, calculating based on the first and second threshold pressure values the weight of the load.