Weighing Function Actuator Friction State Control

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Solution Overview

Problem

Existing weighing functions in work machines, such as construction equipment, face inaccuracies due to static friction states and end positions of actuators, which cannot be properly accounted for, leading to incorrect weight determinations.

Innovation Solution

A method that checks if an actuator is stationary, initiates a small movement to ensure sliding friction conditions, and triggers weight determination during this movement, allowing the weighing function to accurately account for sliding friction forces while excluding static friction states and end positions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If weight determination is performed during actuator movement, then measurement precision is improved, but static friction states and end positions cause inaccuracies

Engineering Contradiction:
Improveweight determination accuracyVSAvoidweighing function reliability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The invention transforms the static weighing problem into a dynamic one by performing weight determination during actuator movement. The control unit detects when the actuator is in motion and only then activates the weighing function, ensuring that sliding friction conditions prevail rather than static friction. This dynamic approach resolves the contradiction by making measurement precision dependent on the actuator's motion state, thereby excluding static friction states and end positions that cause inaccuracies.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention changes the operational parameter of the actuator from stationary to moving state during weight determination. By detecting the actuator's velocity parameter and only performing weighing when velocity exceeds a threshold value, the system ensures that sliding friction conditions are met. This parameter-based control resolves the reliability issue by dynamically adjusting when weight determination occurs based on the actuator's motion parameter.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If weighing function is activated during actuator movement, then sliding friction forces are accounted for, but actuator must be moved which may affect operation

Engineering Contradiction:
Improveweight determination accuracyVSAvoidoperator control
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The invention applies partial action by initiating only a minimal actuator movement just sufficient to transition from static to sliding friction state, rather than requiring full operational movement. The control unit detects when this minimal movement condition is met and performs the weighing function, then stops the movement. This resolves the ease of operation concern by limiting the actuator movement to the minimum necessary for accurate measurement, without interfering with normal operational movements.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The control unit preliminarily checks the actuator's motion state before activating the weighing function. By detecting whether the actuator is already in motion or can be easily moved into motion, the system prepares the optimal condition for weighing. This preliminary detection and preparation resolves the contradiction by ensuring that weighing only occurs when actuator movement can be easily achieved without disrupting normal operation.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP4148193B1Method for invoking a weighing function of a working machine and working machine
Publication Date: 2024.04.17 ROBERT BOSCH GMBH
  • EP4148193B1 patent drawingFigure 1
  • EP4148193B1 patent drawingFigure 2
  • EP4148193B1 patent drawingFigure 3

AI summary

The invention relates to a method for calling up a weighing function of a working machine (1) which has a boom with one or more boom elements (2, 4) for receiving loads, which are movable by one or more independently acting actuators (8, 10), wherein sensors (20, 21, 22, 24) are provided which are configured to detect state data of the boom, and wherein the weighing function is configured to evaluate detected state data in order to determine a weight of a load received by the boom; comprising, by means of a control unit (18, 28) or a weighing function control unit (29) of the working machine: checking (130) whether at least one actuator of the one or more actuators is stationary;when at least one actuator is stationary, starting (140) a minimum movement of the at least one stationary actuator, wherein the at least one actuator is controlled to initiate the minimum movement, the minimum movement being controlled such that the speed of the minimum movement is less than a predetermined maximum speed; calling (150) the weighing function such that at least one weighing time is within a time interval in which the at least one actuator is moved according to the minimum movement; and ending (160) the minimum movement.