Humanoid Robot Joint Actuation Within a Human-Like Envelope
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Solution Overview
Problem
Humanoid robots face a tradeoff between shape and performance due to the limited volume available for housing actuators within a human-like envelope, with larger actuators providing better performance but requiring a larger space.
Innovation Solution
The use of quasi-direct drive (QDD) linear actuators with low gear ratios, paired with motor controllers, to achieve differential linear actuation in two degrees of freedom for each joint, allowing for a more compact and efficient humanoid robot design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If larger actuators are used to improve performance, then actuator performance is improved, but the robot volume increases beyond the human envelope
Solution Approach 1:
The actuation system is segmented into multiple smaller linear actuators that work in combination rather than using a single large actuator. Each linear actuator provides partial actuation, and their combined differential operation achieves the required two-degree-of-freedom joint movement, allowing the robot to fit within the human envelope while maintaining performance
Solution Approach 2:
The linear actuators serve multiple functions: they provide both position control and force control, and their differential operation enables two-degree-of-freedom actuation. This multi-functionality allows smaller actuators to replace what would traditionally require larger, dedicated actuators for each degree of freedom
2Adaptability or versatility
If traditional actuators are used to achieve two degrees of freedom, then actuation capability is improved, but device complexity increases
Solution Approach 1:
Multiple linear actuators are merged into a single integrated actuation system that controls one joint. The actuators operate in combination with differential linear actuation, where their coordinated movement achieves two degrees of freedom. This merging reduces overall system complexity compared to using separate actuators for each degree of freedom
Solution Approach 2:
The patent replaces traditional rotary actuators with linear actuators, substituting a mechanical system with a different actuation mechanism. This substitution simplifies the actuation system while enabling differential operation for two-degree-of-freedom control
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 approach enables a humanoid robot with improved balance, human-like motion, enhanced collision resilience, and efficient actuation, allowing it to operate in human environments with reduced friction and longer runtime.
Implementation Method 1
at least one pair of joint linear actuators configured to operate in combination to adjust the at least one body joint assembly in two degrees of freedom through differential linear actuation
Data Source
AI summary
A robot (100) includes a body assembly (101) that includes a frame formed of at least one body joint assembly (104-110, 113, 115); and at least one pair of joint linear actuators (202, 204, 206, 208, 210) that form the at least one body joint, the at least one pair of joint linear actuators (202, 204, 206, 208, 210) configured to operate in combination to adjust the at least one body joint assembly (104-110, 113, 115) in two degrees of freedom through differential linear actuation.