Legged Robot Dynamic Balance During Whole-Body Manipulation

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Solution Overview

Problem

Current robots require static balance establishment before operating end-effectors, limiting simultaneous leg movement and end-effector operation, which does not resemble human-like motion.

Innovation Solution

Implementing a dynamic balancing system where the lower body control system manages reaction forces from the surface to maintain balance, allowing the upper body control system to operate end-effectors simultaneously while moving, using inverse kinematics and coordinated control of a lower and upper body control system.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the robot establishes static balance before operating end-effectors, then the robot maintains stable balance, but the robot cannot move legs and operate end-effectors simultaneously

Engineering Contradiction:
Improvesimultaneous leg movement and end-effector operationVSAvoidbalance stability
Core Design Contradiction:
Ease of operationVSStability of the object's composition

Solution Approach 1:

The patent transitions from static balance to dynamic balance control. The lower body control system continuously adjusts leg forces to maintain balance during motion, allowing the robot to move and operate end-effectors simultaneously while maintaining stability through active feedback control rather than passive static positioning.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent divides the control system into separate lower body control and upper body control modules. The lower body control system manages balance and leg movements independently, while the upper body control system operates end-effectors, enabling simultaneous operations without interference between the two functions.

Inventive Principle:
Principle #1Segmentation

2Measurement precision

If the robot interrupts gait to operate end-effectors, then the robot can perform precise end-effector tasks, but the robot loses continuous movement capability

Engineering Contradiction:
Improveend-effector positioning precisionVSAvoidcontinuous movement speed
Core Design Contradiction:
Measurement precisionVSSpeed

Solution Approach 1:

The dynamic balance control enables the robot to maintain stability during continuous motion, allowing end-effectors to operate at any point in the gait cycle without interrupting movement. This resolves the contradiction by enabling both precise end-effector control and continuous locomotion through coordinated dynamic adjustment of leg forces.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent enables continuous gait operation without interruptions by maintaining dynamic balance throughout the motion cycle. The lower body control system continuously adjusts to support end-effector operations at any moment, ensuring unbroken locomotion while performing tasks.

Inventive Principle:
Principle #20Continuity of useful action

3Adaptability or versatility

If the robot uses static balance control, then the control system is simpler, but the robot cannot perform whole body manipulation during movement

Engineering Contradiction:
Improvewhole body manipulation capabilityVSAvoidcontrol system complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The control system is segmented into lower body control and upper body control modules with distinct responsibilities. This modular architecture manages complexity by separating balance control from task execution, enabling versatile whole body manipulation while keeping each control module relatively simple and focused.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The transition to dynamic balance control adds adaptability for whole body manipulation during movement. The continuous adjustment capability allows the robot to perform complex tasks while moving, with the control complexity managed through the segmented modular structure.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3875229B1Whole body manipulation on a legged robot using dynamic balance
Publication Date: 2023.11.22 BOSTON DYNAMICS INC
  • EP3875229B1 patent drawingFigure 1
  • EP3875229B1 patent drawingFigure 2
  • EP3875229B1 patent drawingFigure 3

AI summary

A robot system (400) includes: an upper body section (408b) including one or more end-effectors (422, 424); a lower body section (408a) including one or more legs (404, 406); and an intermediate body section (408c) coupling the upper and lower body sections. An upper body control system (417b) operates at least one of the end-effectors. The intermediate body section experiences a first intermediate body linear force and/or moment based on an end-effector force acting on the at least one end-effector. A lower body control system operates (417a) the one or more legs. The legs experience respective surface reaction forces. The intermediate body section experiences a second intermediate body linear force and/or moment based on the surface reaction forces. The one or more legs operate so that the second intermediate body linear force balances the first intermediate linear force and the second intermediate body moment balances the first intermediate body moment.