Three-Motor Leg Assembly for Wider 3D Robot Motion

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Solution Overview

Problem

Legged robots have limited movement range and low degree of freedom, restricting their ability to perform complex actions and adapt to user needs.

Innovation Solution

A leg assembly for legged robots featuring a configuration of three motors and a transmission component that allows for wide movement in three-dimensional space, with specific stop portions and flanges to limit rotation angles, enhancing the robot's adaptability and movement range.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a traditional joint structure is used in the leg assembly, then the structure is simple, but the movement range is narrow and the degree of freedom is low

Engineering Contradiction:
Improvemovement rangeVSAvoidjoint structure complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The leg assembly is divided into multiple independent joint modules (first joint, second joint, third joint), each capable of independent rotation. This segmentation allows each joint to contribute to the overall movement range while maintaining manageable structural complexity through modular design.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces multi-axis rotation capabilities by arranging joint axes in different spatial orientations (first joint axis, second joint axis perpendicular to the first, third joint axis parallel to the second). This dimensional arrangement transforms a single-plane movement system into a three-dimensional movement system, dramatically expanding the movement range.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Adaptability or versatility

If more motors and transmission components are added to increase degree of freedom, then the movement capability improves, but the device complexity increases

Engineering Contradiction:
Improvedegree of freedomVSAvoidmotor and transmission structure
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

Multiple transmission components (first transmission component, second transmission component, third transmission component) are merged into a compact integrated structure where components share common elements such as the first link and various joints. This merging reduces the total number of independent parts while maintaining three degrees of freedom.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The first link serves multiple functions: it acts as an output link for the first joint, a connecting link for the second joint, and supports the third joint. This multi-functionality reduces the need for separate components for each function, thereby increasing degree of freedom without proportionally increasing device complexity.

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

3Adaptability or versatility

If the movement range is expanded to perform complex actions, then the adaptability improves, but the control precision becomes more difficult to maintain

Engineering Contradiction:
Improvecomplex action capabilityVSAvoidcontrol precision
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

Each joint is equipped with a motor (first motor, second motor, third motor) that can provide precise control and feedback mechanisms. This allows the system to maintain control precision across the expanded movement range by continuously monitoring and adjusting the position of each joint independently.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The leg assembly employs dynamic transmission components including cranks, connecting rods, and pivotable links that enable smooth, controlled motion through the full range of movement. The dynamic design allows for precise positioning at any point within the expanded movement envelope while maintaining control accuracy.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP4059817B1Leg assembly for legged robot and legged robot
Publication Date: 2024.11.27 BEIJING XIAOMI ROBOT TECH CO LTD
  • EP4059817B1 patent drawingFigure 1
  • EP4059817B1 patent drawingFigure 2
  • EP4059817B1 patent drawingFigure 3

AI summary

A leg assembly for a legged robot includes first through three motors, first through second legs, and a transmission component. The first motor is coupled to the second motor to drive the second motor to rotate, and a rotation axis of the first motor is substantially orthogonal to a rotation axis of the second motor. The second motor is coupled to the third motor to drive the third motor to rotate, and a rotation axis of the third motor substantially coincides with the rotation axis of the second motor. The third motor is arranged at a first end of the first leg, the second leg is pivotably coupled to a second end of the first leg, and the transmission component is coupled to an output shaft of the third motor and the second leg to drive the second leg to rotate relative to the first leg.