Robot Hydraulic Load Balancing for Peak Torque Equalization

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Solution Overview

Problem

Multi-axis robots face challenges with peak loads and energy requirements due to the increased holding torques and inertia in their drive axes, which can lead to unfavorable operating conditions and inefficiencies.

Innovation Solution

A fluidic load equalization arrangement is introduced, featuring a hydraulic cylinder connected to two movable coupling members, a pressure accumulator, and a control unit with controllable valves to manage fluid flow between the hydraulic cylinder and the pressure accumulator, allowing for two operating modes that adjust the pressure-displacement characteristic to optimize energy storage and release during relative movement of the coupling links.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a multi-axis robot with serial kinematics is used, then the robot can achieve complex movements and positioning, but the holding torques and inertia increase leading to higher energy requirements and unfavorable operating conditions

Engineering Contradiction:
Improverobot movement capabilityVSAvoidenergy requirement
Core Design Contradiction:
Adaptability or versatilityVSUse of energy by moving object

Solution Approach 1:

The load equalization arrangement stores energy in advance during phases when the robot structure assumes positions with lower gravitational potential energy. This pre-stored energy is then released during phases requiring higher energy input, thereby equalizing the energy demand across different operating phases and reducing peak power requirements.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention employs a hydraulic cylinder connected to a pressure accumulator to create a fluid-based energy storage and release system. The hydraulic system transforms mechanical energy from the robot's movement into hydraulic pressure energy, which is stored in the accumulator and can be rapidly released when needed, effectively managing the energy fluctuations in the serial kinematic chain.

Inventive Principle:
Principle #29Pneumatics and hydraulics

2Use of energy by moving object

If load balancing arrangements are added to reduce holding torques, then energy requirements decrease, but device complexity increases

Engineering Contradiction:
Improveenergy requirementVSAvoidsystem complexity
Core Design Contradiction:
Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The load equalization arrangement serves multiple functions simultaneously: it acts as both a load balancing mechanism to reduce holding torques and an energy storage system to equalize power requirements. By combining these functions into a single integrated system, the invention avoids the need for separate complex mechanisms for each function.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The hydraulic cylinder and pressure accumulator serve as intermediary elements between the robot's mechanical structure and the energy management system. These components mediate the transformation and storage of energy, providing a buffer that simplifies the overall system architecture compared to direct mechanical load balancing approaches.

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

This solution reduces the basic energy requirement for the robot's motors, optimally compensates for peak loads, and enhances the operating behavior by smoothing dynamic and static loads, while being cost-effective and increasing the functionality of the load balancing arrangement.

Implementation Method 1

at least one pressure accumulator which can be coupled to the hydraulic cylinder

Methodology Applied
Scientific EffectHydraulic pressure: Pressure Increase

Implementation Method 2

which can be compressed and in which the hydraulic fluid displaced by the hydraulic cylinder can be received

Methodology Applied
Scientific EffectFluid compression: Compression

Data Source

PatentEP3311961B9Robot and load balancer for a robot
Publication Date: 2021.11.24 BUCHER HYDRAULICS ERDING GMBH
  • EP3311961B9 patent drawingFigure 1~2
  • EP3311961B9 patent drawingFigure 3
  • EP3311961B9 patent drawingFigure 4

AI summary

The disclosure relates to a robot and a fluidic load-balancing arrangement for a robot, which has at least two coupling links (14, 16) that are connected to one another in an articulated manner, the load-balancing arrangement having a hydraulic cylinder (62) that is attached to two coupling links (14, 16) that can move relative to one another , wherein a first end of the hydraulic cylinder (62) is connected to a first coupling element (14) and a second end is connected to a second coupling element (16), at least one pressure accumulator (78) which can be coupled to the hydraulic cylinder (62), and to a Control unit (96) is provided, which is arranged between the hydraulic cylinder (62) and the at least one pressure accumulator (78) in order to fluidly couple the hydraulic cylinder (62) and the at least one pressure accumulator (78) to one another, the control unit (96) a first fluid path (88) and a second fluid path (90) between the hydraulic cylinder (62) and the at least one pressure accumulator (78) assigned net is, and wherein a controllable valve (100) is provided in the second fluid path (90) which can be operated in a first operating state and a second operating state in order to selectively allow a fluid flow through the first fluid path or the second fluid path.