Mechanical Finger With Passive Phalanges For Adaptive Grasping
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Solution Overview
Problem
Existing robotic grasping apparatuses face challenges in replicating human-like grasping motions while simplifying design, reducing parts, and using off-the-shelf components, as they struggle to efficiently adapt to various object shapes and sizes with minimal actuation degrees.
Innovation Solution
A mechanical finger design featuring a base connected to an actuator, multiple phalanges with passive rotational degrees of freedom, and a transmission linkage that maintains constant orientation until object contact, allowing for pinch and enveloping grasps with minimal active actuation, using revolute joints and stoppers to constrain movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If passive rotational DOF joints are used in the mechanical finger, then the number of actuation degrees is reduced and design is simplified, but the ability to replicate human-like grasping motions is limited
Solution Approach 1:
The mechanical finger uses passive rotational DOF joints that automatically adapt to object contact without active actuation. The phalanges self-adjust their orientation through passive rotation when contacting objects of different shapes and sizes, eliminating the need for complex active control systems while maintaining human-like grasping capabilities
Solution Approach 2:
The mechanical finger changes its configuration parameters dynamically through passive rotation of phalanges. When an object is contacted, the phalanges rotate to conform to the object's geometry, allowing the system to adapt to various grasping scenarios with a single actuation degree rather than requiring multiple fixed DOFs
2Ease of manufacture
If the mechanical finger uses a transmission linkage with passive rotational DOF joints, then the fabrication and assembly processes are simplified, but the precision of phalanx orientation control is reduced
Solution Approach 1:
The patent replaces active mechanical control systems with a passive transmission linkage mechanism. The linkage uses geometric constraints and passive rotational joints to achieve precise phalanx orientation control without requiring complex actuators, sensors, or control algorithms, thereby simplifying fabrication and assembly while maintaining control precision
Solution Approach 2:
The transmission linkage is divided into multiple segments (proximal link, distal link, phalanges) connected by passive rotational DOF joints. This segmentation allows each component to be manufactured independently using standard off-the-shelf components, simplifying fabrication and assembly while the coordinated motion of segments maintains precise orientation control
Data Source
AI summary
A mechanical finger has a base adapted to be connected to an actuator for being displaced in at least one degree of actuation, and has two or more phalanges. A first phalanx is rotationally connected at a proximal end to the base, and a second phalanx is rotationally connected at a proximal end to a distal end of the first phalanx. A transmission linkage providing at least one rotational degree of freedom (DOF) between the base and a distal-most one of the phalanges. Passive rotational DOF joints are between the phalanges, between the base and the first phalanx, and in the transmission linkage, whereby the mechanical finger has a passive state of actuation in which the base, the at least two phalanges and the transmission linkage remain in a constant orientation relative to one another through displacement of the base caused by the actuator absent a contact of one of the phalanges with an object, and a grasping state of actuation in which a contact of at least one of the phalanges with an object causes a variation of the orientation of at least one of the phalanges relative to the base through displacement of the base caused by the actuator.