Robot Shoulder Roll Rotation Structure Using Linear Actuator Extraction
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Solution Overview
Problem
Conventional roll rotation structures for humanoid robots require large shoulder parts due to the placement of actuators, leading to increased size, weight, and energy consumption, as well as limited movable range.
Innovation Solution
A roll rotation structure using a linear motion actuator located outside the shoulder part, with its output shaft capable of being drawn into the shoulder part to transmit rotational motion to the arm unit, reducing the need for internal space and actuator size within the shoulder.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a servo-motor is arranged inside the shoulder part for roll rotation, then the arm unit can be rotationally driven around the roll axis, but the shoulder part becomes large in size
Solution Approach 1:
The actuator (servo-motor) is extracted from the shoulder part and arranged in the robot body instead. Only the necessary transmission components (belt, pulley, output shaft) remain in the shoulder part, significantly reducing its size while maintaining the roll rotation capability of the arm unit
Solution Approach 2:
The system is segmented into two parts: the actuator located in the robot body and the transmission mechanism located in the shoulder part. This segmentation allows the heavy actuator to be positioned away from the shoulder, reducing the shoulder part size while preserving functionality
2Device complexity
If the actuator is arranged inside the shoulder part, then the structure is compact, but the distance between the roll axis and output shaft becomes short, requiring large rigidity and increasing actuator size
Solution Approach 1:
The actuator is extracted from the shoulder part, allowing the output shaft to be positioned at an optimal distance from the roll axis. This increased distance reduces the rigidity requirements and allows for a smaller, less complex actuator design
Solution Approach 2:
A belt transmission mechanism is introduced as an intermediary between the actuator output shaft and the roll axis. This allows flexible power transmission over a longer distance, reducing the direct coupling requirements and rigidity demands on the actuator
3Device complexity
If the actuator is arranged in the shoulder part, then the structure is simplified, but the rotation load increases, requiring larger actuators and increasing energy consumption
Solution Approach 1:
The actuator is extracted from the shoulder part and repositioned in the robot body. This redistribution of mass reduces the moment of inertia and rotation load on the actuator, thereby reducing energy consumption during arm unit rotation while maintaining structural simplicity through the belt transmission system
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 design minimizes the shoulder part's size, reducing weight and energy consumption while maintaining the necessary range of motion for the robot's arm unit.
Implementation Method 1
a linear motion actuator having output shaft that moves linearly... an output from the output shaft of the linear motion actuator produces an angular moment in the roll direction
Data Source
AI summary
A roll rotation structure for rotationally driving, in a roll direction of a robot, an arm unit mounted on a shoulder part of the robot through a roll support part comprises a linear motion actuator having an output shaft that moves linearly, a mounting part by which the linear motion actuator is mounted on the shoulder part in such a manner that a main body of the linear motion actuator is located at the side of a main body of the robot adjacent to the shoulder part, and that the output shaft of the linear motion actuator can be drawn into and out of the shoulder part, and a connection part that connects the output shaft and the arm unit in such a manner that an output from the output shaft of the linear motion actuator produces an angular moment in the roll direction in the roll support part.