Underactuated Humanoid Robot Hand with Elastic Linkage
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Solution Overview
Problem
Existing humanoid robot hands face challenges in independently controlling the complex movements of fingers for grasping objects and visual communication while maintaining a high degree of underactuation, requiring a mechanism that can efficiently control multiple degrees of freedom with a minimal number of actuators.
Innovation Solution
A hand design featuring a first mechanism that links the palm to phalanges, allowing rotational mobility and a second mechanism with elastic bars and cables to deform and wrap around objects, enabling grasping with a single actuator while allowing for various finger movements and adaptability to object shapes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a high degree of underactuation is maintained with a single actuator, then the number of actuators is minimized, but the control precision and independent movement capability of each finger is reduced
Solution Approach 1:
The finger is divided into multiple functional segments: a first mechanism for basic rotational movement (IP joint) and a second mechanism for grasping movement (MP and TIP joints). This segmentation allows each mechanism to be controlled independently, enabling precise control of specific finger portions while maintaining overall underactuation.
Solution Approach 2:
The patent implements dynamic control where the second mechanism can deform the first mechanism during grasping operations. This dynamic interaction allows the finger to adapt its configuration based on the grasping task, improving control precision without requiring additional actuators for each joint.
2Device complexity
If the finger structure is simplified to reduce actuator requirements, then the degree of underactuation increases, but the ability to perform complex movements for both grasping and visual communication is reduced
Solution Approach 1:
The finger is segmented into a proximal portion (first mechanism for IP joint rotation) and a distal portion (second mechanism for MP and TIP joints). This allows independent control of each segment, enabling complex movements like pointing (using distal joints) while maintaining simplified overall structure.
Solution Approach 2:
The two mechanisms work together to provide multiple functions: the first mechanism enables basic finger rotation for communication gestures, while the second mechanism enables grasping movements. The combination allows the same finger structure to perform both grasping and visual communication tasks.
3Adaptability or versatility
If elastic bars are used in the first mechanism, then the mechanism can be deformed by the second mechanism during grasping, but the structural stability and rotational control are compromised
Solution Approach 1:
The patent uses elastic bars with specific material properties that allow controlled deformation under load. The elasticity parameter is selected to permit deformation when force is applied by the second mechanism during grasping, while maintaining sufficient structural stability for normal rotational movement and communication gestures.
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 enhances the humanoid robot's interaction capabilities by allowing complex finger movements and grasping of diverse objects with reduced actuator requirements, maintaining a high degree of underactuation and minimizing the need for additional control devices.
Implementation Method 1
the first mechanism comprises a first bar and a second bar which are elastic bars
Data Source
AI summary
A hand intended to equip a humanoid robot, the hand includes a palm and at least one finger extending along a first axis, the hand being capable of picking up an object, the finger comprising a first phalanx linked to the palm by a first motorized pivot link and a second phalanx consecutive to the first phalanx linked to the first phalanx by a second pivot link. The finger comprises a first mechanism linking the palm to the second phalanx configured such that the rotation of the first phalanx about the second axis causes the second phalanx to rotate about the third axis, and a second mechanism linking the palm to each of the phalanges configured to actuate the finger in such a way that the finger wraps around the object to be picked up, and the second mechanism is configured to deform the first mechanism.