Convertible manipulator/sheer

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 :

Women in Tech leadership resources from IMTS 2022

There’ve been quite a few events recently focusing on Women in Robotics, Women in Manufacturing, Women in 3D Printing, in Engineering, and in Tech Leadership. One of the largest tradeshows in the US is IMTS 2022. Here I bring you some resources shared in the curated technical content and leadership sessions.
29 September 2022, by and

MIT engineers build a battery-free, wireless underwater camera

The device could help scientists explore unknown regions of the ocean, track pollution, or monitor the effects of climate change.
27 September 2022, by

How do we control robots on the moon?

In the future, we imagine that teams of robots will explore and develop the surface of nearby planets, moons and asteroids - taking samples, building structures, deploying instruments.
25 September 2022, by , and

Have a say on these robotics solutions before they enter the market!

We have gathered robots which are being developed right now or have just entered the market. We have set these up in a survey style consultation.
24 September 2022, by

Shelf-stocking robots with independent movement

A robot that helps store employees by moving independently through the supermarket and shelving products. According to cognitive robotics researcher Carlos Hernández Corbato, this may be possible in the future. If we engineer the unexpected.
23 September 2022, by

RoboCup humanoid league: Interview with Jasper Güldenstein

We talked to Jasper Güldenstein about how teams transferred developments from the virtual humanoid league to the real-world league.
20 September 2022, by and

©2021 - ROBOTS Association


©2021 - ROBOTS Association