Robot Arm Assembly Single Servo Transmission

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Solution Overview

Problem

Humanoid robots require multiple servos to achieve rotational degrees of freedom, which increases complexity and cost, necessitating a design that minimizes the number of servos needed.

Innovation Solution

A robot arm assembly configuration using a single servo to drive both the upper arm and forearm, with a transmission mechanism that allows coordinated rotation, reducing the number of servos required and simplifying motion control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple servos are used to provide rotational degrees of freedom for each joint, then the robot can achieve human-like movement, but the device complexity and cost increase

Engineering Contradiction:

Improverotational degrees of freedomVSAvoidnumber of servos

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

A single servo unit is designed to perform multiple functions by providing rotational drive to both the upper arm and forearm through a transmission mechanism. The servo acts as a universal drive source that can control different joints sequentially or simultaneously, replacing what would traditionally require separate servos for each degree of freedom.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent combines multiple drive functions into a single servo unit. By merging the drive capabilities that would traditionally be separate into one integrated servo, the system reduces component count while maintaining the ability to provide necessary rotational movement for arm elevation and forearm rotation through mechanical transmission.

Inventive Principle:

Principle #5Merging (Combining)

2Ease of operation

If multiple servos are used to control each joint independently, then precise motion control is achieved, but the motion control algorithm complexity increases

Engineering Contradiction:

Improvemotion control precisionVSAvoidmotion control algorithm

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The transmission mechanism dynamically adapts its motion transmission based on the operational phase. During arm elevation, the mechanism transmits rotational motion from the servo to the upper arm; during forearm rotation, it redirects the motion transmission path. This dynamic behavior allows a single servo to control multiple joints with different degrees of freedom without requiring complex coordinated control algorithms.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The transmission mechanism acts as an intermediary between the single servo and the multiple joints. It mediates the motion transmission, converting the servo's single rotational output into appropriate motion for different joints at different times, thereby simplifying the control algorithm while maintaining motion precision.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS10773395B2Robot and arm assembly thereof

Publication Date: 2020.09.15 UBTECH ROBOTICS CORP LTD

AI summary

An arm assembly includes a servo coupled to the chest of the robot, an upper arm driven by the servo, a forearm rotatably coupled to the upper arm, and a forearm transmission member comprising a first end rotatable with respect to the chest and a second end coupled to the forearm. The upper arm, the forearm and the forearm transmission member are arranged in such a way that the forearm rotates when the upper arm rotates with respect to the chest.