Robohub.org
 

Convertible manipulator/sheer


by
02 March 2009



share this:

A manipulator with four or six ‘fingers’ positioned symmetrically around a central axis might also serve as a sheer, able to snip along two or three planes. The cutting edges would be the edges of basal segments to which the fingers were mounted. Four-fingered manipulators would be mechanically simpler and more robust. Six-fingered manipulators would have sharper edges and therefore make more efficient sheers. In either case, to act as a sheer the fingers would have to reach past the object (stem) to be cut, so it could be grasped by their basal segments.

 

An alternative to the above would be a four fingered manipulator with basal segments angled at less than 90 degrees, possibly as little as 45 degrees, with space between them, and the ability to rotate into that space. In the case of 45 degree angled basal segments, each finger should be able to rotate 22.5 degrees in either direction from its rest position. This would result in both a manipulator with two sets of opposed digits, 45 degrees apart on either side, arranged along either of two axes, as well as a more effective sheer. [2012Oct13: This allows switching the plane of the gripper formed by the fingers 90 degrees through finger rotation alone, no wrist rotation needed.]

 

The basal segments to which I’ve been referring would appear, from anywhere along the central axis, like simple blocks of metal presenting a distinct edge. However, from the outside, with those edges hidden, they would look more like the links in multi-jointed digits that they would also be.

 

[2012Oct13: To be quite honest, I’ve never been able to imagine exactly how the basal sheer would work in practice, how the parts would connect and be activated. This aspect now seems far less useful than the ability to regroup fingers to form grippers, switching between perpendicular planes, by rotating each finger 45 degrees. For pruning, you’d want a gripper next to a sheer, with the whole assembly being rotatable, so you could hold onto the branch you were removing while cutting it loose, and then pull it free.]

 

Reposted from Cultibotics.



tags:


John Payne





Related posts :



Researchers are teaching robots to walk on Mars from the sand of New Mexico

  02 Sep 2025
Researchers are closer to equipping a dog-like robot to conduct science on the surface of Mars

Engineering fantasy into reality

  26 Aug 2025
PhD student Erik Ballesteros is building “Doc Ock” arms for future astronauts.

RoboCup@Work League: Interview with Christoph Steup

and   22 Aug 2025
Find out more about the RoboCup League focussed on industrial production systems.

Interview with Haimin Hu: Game-theoretic integration of safety, interaction and learning for human-centered autonomy

and   21 Aug 2025
Hear from Haimin in the latest in our series featuring the 2025 AAAI / ACM SIGAI Doctoral Consortium participants.

AIhub coffee corner: Agentic AI

  15 Aug 2025
The AIhub coffee corner captures the musings of AI experts over a short conversation.

Interview with Kate Candon: Leveraging explicit and implicit feedback in human-robot interactions

and   25 Jul 2025
Hear from PhD student Kate about her work on human-robot interactions.

#RoboCup2025: social media round-up part 2

  24 Jul 2025
Find out what participants got up to during the second half of RoboCup2025 in Salvador, Brazil.

#RoboCup2025: social media round-up 1

  21 Jul 2025
Find out what participants got up to during the opening days of RoboCup2025 in Salvador, Brazil.



 

Robohub is supported by:




Would you like to learn how to tell impactful stories about your robot or AI system?


scicomm
training the next generation of science communicators in robotics & AI


 












©2025.05 - Association for the Understanding of Artificial Intelligence