Legged Robot Self-Righting Through Sensor-Guided Leg Movements

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Solution Overview

Problem

Robotic devices often fall or tip over, making it difficult and time-consuming for operators to re-orient them to a stable position.

Innovation Solution

A self-righting method and system for legged robotic devices that determine their unstable orientation using sensors and processors, performing actions such as moving legs to increase gravitational potential energy and adjust leg positions to achieve stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If operators manually re-orient the robotic device to a stable position, then the robotic device can return to normal operation, but the process is difficult and time-consuming

Engineering Contradiction:
Improveease of returning to stable positionVSAvoidtime to return to stable position
Core Design Contradiction:
Ease of operationVSLoss of time

Solution Approach 1:

The robotic device autonomously determines its own unstable orientation using onboard sensors and processors, and automatically executes self-righting actions by moving its legs without human intervention. The system monitors its own state through sensor data and independently decides and performs the necessary actions to return to a stable position, making the device self-sufficient in recovering from falls.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The robotic device performs preliminary assessment of its orientation state using sensors before executing self-righting actions. By detecting its current unstable position in advance and planning the appropriate leg movements beforehand, the system can quickly and efficiently transition to a stable position without trial-and-error maneuvers.

Inventive Principle:
Principle #10Preliminary action

2Extent of automation

If the robotic device performs complex self-righting maneuvers, then it can autonomously return to stable position, but the complexity of control increases

Engineering Contradiction:
Improveautonomous self-righting capabilityVSAvoidcontrol system complexity
Core Design Contradiction:
Extent of automationVSDevice complexity

Solution Approach 1:

The self-righting process is divided into distinct segments: orientation detection using sensors, determination of unstable position by the processor, selection of appropriate self-righting actions, and execution of leg movements. This segmentation allows the complex autonomous function to be implemented through modular, manageable control steps rather than a monolithic complex system.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The robotic device uses onboard sensors to continuously monitor its orientation and position, providing feedback to the processor. The processor compares the detected orientation against stable position criteria and adjusts the control commands accordingly, creating a closed-loop feedback system that enables autonomous self-righting while maintaining manageable complexity through adaptive control.

Inventive Principle:
Principle #23Feedback

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

Enables robotic devices to autonomously return to a stable position, allowing them to resume normal operation efficiently.

Implementation Method 1

determining an orientation of a bottom surface of a legged robotic device with respect to a ground surface

Methodology Applied
Scientific EffectOrientation detection:

Implementation Method 2

extending the distal end of the first leg of the legged robotic device away from the body of the legged robotic device such that a gravitational potential energy of the legged robotic device is increased

Methodology Applied
Scientific EffectGravitational potential energy: Gravitation

Data Source

PatentEP3835004B1Systems and methods for robotic self-right
Publication Date: 2025.08.06 BOSTON DYNAMICS INC
  • EP3835004B1 patent drawingFigure 1
  • EP3835004B1 patent drawingFigure 2
  • EP3835004B1 patent drawingFigure 3A~3B

AI summary

Example systems and methods for self-righting a robotic device are provided. An example method may include determining an orientation of a bottom surface of a legged robotic device with respect to a ground surface. The method may also include determining that the robotic device is in an unstable position, based on the determined orientation. The method may also include performing a first action configured to return the robotic device to a stable position. The method may also include performing a first action configured to return the legged robotic device to the stable position. The method may also include performing a second action configured to return the legged robotic device to the stable position, if the legged robotic device is in the unstable position after the first action.