Dual-Arm Gravity Compensation for Load Manipulation

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Solution Overview

Problem

Existing load handling devices are complex, expensive, and lack consistent gravity compensation, depriving users of physical perception of load behavior, making them unsuitable for demanding environments and trades.

Innovation Solution

A load handling device with two articulated arms, where each segment of the second arm is shorter but heavier than the corresponding segment of the first arm, with synchronized movement transmission to achieve complete mass compensation, allowing physical perception of load characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a load is held stationary against gravity, then the load position is maintained, but actuators must continuously consume energy to counteract gravity

Engineering Contradiction:
Improveload position maintenanceVSAvoidactuator energy consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent employs a counterweight mechanism where a mass is positioned to generate a gravitational force that balances the load weight. This creates a near-equilibrium state where the actuator only needs to provide minimal force to maintain position, dramatically reducing continuous energy consumption while keeping the load stationary.

Inventive Principle:
Principle #8Anti-weight (Counterweight)

Solution Approach 2:

The patent replaces traditional mechanical gravity compensation mechanisms with a magnetic field-based system. Magnets generate holding forces that counteract gravity without mechanical contact, eliminating friction and enabling precise position maintenance with minimal energy input through electromagnetic fields rather than continuous mechanical force.

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

2Length of moving object

If actuators are sized to handle maximum load movements, then full range of motion is achieved, but actuators are oversized for stationary holding

Engineering Contradiction:
Improveactuator stroke rangeVSAvoidactuator sizing optimization
Core Design Contradiction:
Length of moving objectVSDevice complexity

Solution Approach 1:

The patent implements a dynamic actuator sizing strategy where the actuator operates in different modes: full-stroke operation during load movement and minimal-adjustment mode during stationary holding. The counterweight system enables the actuator to maintain position with minimal force output, allowing the same actuator to be optimally sized for both full-range motion and stationary holding without oversizing.

Inventive Principle:
Principle #15Dynamics

3Reliability

If brake systems are used to hold loads, then stationary positioning is achieved, but mechanical wear and maintenance are increased

Engineering Contradiction:
Improveload holding capabilityVSAvoidmechanical wear
Core Design Contradiction:
ReliabilityVSEase of repair

Solution Approach 1:

The patent replaces mechanical brake systems with a magnetic field-based holding system. Electromagnets or permanent magnets generate holding forces that counteract gravity without mechanical contact, eliminating friction, wear, and the need for periodic brake maintenance while maintaining reliable load holding capability.

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

Solution Approach 2:

The patent introduces a magnetic field as an intermediary between the actuator and the load. This magnetic field serves as the holding mechanism, replacing direct mechanical contact and brake systems. The magnetic field provides contactless force transmission, eliminating mechanical wear while maintaining the ability to hold loads stationary.

Inventive Principle:
Principle #24Intermediary (Mediator)

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

The device provides robust, cost-effective load handling suitable for complex environments, enabling precise manipulation by maintaining user perception of load behavior and reducing energy consumption.

Implementation Method 1

a magnet is provided in the movable element which has a holding force in a second direction opposite to the direction of gravity

Methodology Applied
Scientific EffectMagnetic field: Magnetic Field

Data Source

PatentEP4496680B1Device for manipulating a load with gravity compensation
Publication Date: 2026.04.29 NANTES UNIVERSITÉ (33 33)
  • EP4496680B1 patent drawingFigure 1~2
  • EP4496680B1 patent drawingFigure 3a~3c
  • EP4496680B1 patent drawingFigure 4a~4b

AI summary

The invention relates to a device (DM) for manipulating a load, comprising a first articulated arm (BA1) extending from a base (B) to one end of said first arm, which end comprises means for fastening the load, the first arm being formed by a succession of segments connected by joints. This device comprises a second articulated arm (BA2) with a similar structure to that of the first arm. The first and second arms extend on either side of the base, each segment of the second arm being shorter in length and greater in mass than an associated same-position segment of the first arm, the length and mass being dimensioned so that the mass-length product is substantially equivalent for two associated segments. Means for transmitting movements between associated segments are configured such that a movement of a segment of one of the arms causes a movement of the same amplitude of the associated segment of the other arm.