Excavator Standby Torque Control for Boom Sag Prevention

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Solution Overview

Problem

Existing excavator control systems fail to effectively prevent unintended falling and sagging of working apparatuses due to the lack of a valid standby torque value, which is necessary to maintain the apparatuses' position when the brake is released, and there is no reliable method to determine if the saved torque value is sufficient for the changing state of the apparatus.

Innovation Solution

A method and device for controlling excavators that determine the validity of a saved torque value by considering weight, position, and torque information, and if invalid, use a standby torque value table or maximum motor torque to ensure the apparatuses maintain their position when the brake is released.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the brake is applied to working apparatuses to maintain position, then the apparatuses are held stationary, but the saved torque value may become invalid when the apparatus state changes, causing falling and sagging

Engineering Contradiction:

Improveposition maintenance reliabilityVSAvoidadaptability to changing apparatus state

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The control device continuously monitors apparatus status information (weight, position, torque) and compares it with saved torque values to determine validity. This feedback mechanism ensures the standby torque value remains valid even when apparatus state changes, preventing falling and sagging while adapting to new conditions.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The control device saves torque values at the time of brake application and validates them before brake release. This preliminary action of saving and validating torque values ensures that a reliable standby torque value is ready before the brake is released, preventing position loss.

Inventive Principle:

Principle #10Preliminary action

2Ease of operation

If the brake is released to allow movement, then the working apparatus can change position, but unintended falling and sagging occurs without a valid standby torque value

Engineering Contradiction:

Improveease of position adjustmentVSAvoidposition stability

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The control device acts as an intermediary between the brake application and release, validating the standby torque value before allowing brake release. This intermediary check ensures that position adjustments can be made safely without causing unintended falling or sagging.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The control device validates the standby torque value in advance before the brake is released. This preliminary validation ensures that the apparatus has sufficient torque support before movement begins, preventing falling and sagging while allowing smooth position changes.

Inventive Principle:

Principle #10Preliminary action

3Ease of operation

If the saved torque value is always used as standby torque value, then the system is simple to operate, but it cannot determine whether the torque value is sufficient when apparatus state changes

Engineering Contradiction:

Improveease of torque value managementVSAvoidtorque value sufficiency determination

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The control device obtains apparatus status information (weight, position, torque) and uses it to determine whether the saved torque value is valid. This feedback mechanism maintains operational simplicity while accurately determining torque sufficiency based on current apparatus state.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The control device changes the standby torque value based on apparatus status parameters (weight, position, torque). When the apparatus state changes significantly, the system updates the standby torque value to reflect current conditions, ensuring accurate torque sufficiency determination while maintaining ease of operation.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS20250382778A1Method and Device for Controlling Excavator Using Standby Torque

Publication Date: 2025.12.18 VOLVO CONSTRUCTION EQUIPMENT AB

AI summary

The present disclosure pertains to a method for obtaining apparatus status information including at least one of weight, position, and torque value information according to movement for one or more working apparatuses including at least one of a boom, an arm, and a bucket included in an excavator; indicating a torque value corresponding to a time when a brake is applied to the one or more working apparatuses and determining whether a final saved torque value obtained based on the torque value information according to the movement is valid; determining, if the final saved torque value is valid, the final saved torque value as a standby torque value required for the one or more working apparatuses; and controlling the one or more working apparatuses based on the standby torque value at a time when the brake is released, which is a time after the time when the brake is applied.