# @stem_antics on Instagram

- **Type:** Video
- **Original URL:** https://www.instagram.com/p/DdFU8kTvW2B
- **Gondola URL:** https://gondola.cc/posts/70280831-stem-antics-instagram
- **Thumbnail:** https://img.gondola.cc/tr:w-,h-,fo-auto/postThumbnails/76bdd766f7.jpg
- **Posted:** 2026-09-09T22:24:55.000+00:00
- **Account Owner:** Stem Antics (@stem_antics) — https://gondola.cc/stem_antics

## Caption

A sorting robot on a factory line does not need arms, eyes or a torso. It needs a stiff parallel linkage, a camera, and a clock that every subsystem agrees on.

The workhorse is the delta robot, developed by Reymond Clavel at EPFL and patented in 1987. Three motors sit fixed on an overhead base plate and drive three upper arms. Each upper arm connects to the moving platform through a parallelogram of thin carbon fibre rods, and that parallelogram constrains the platform to stay parallel to the base at all times. The result is three degrees of translational freedom, plus an optional fourth rotation delivered by a telescoping central shaft.

Fixing the motors to the frame is the whole trick. Moving mass falls to a few hundred grams of rod and platform rather than a serial chain of heavy actuators, so peak accelerations reach 10 to 15 g and a production delta cell sustains 150 to 300 picks per minute.

Sorting then demands that robot and belt share one coordinate frame:

- An incremental encoder on the conveyor shaft streams belt position into the controller
- A camera triggers on that encoder count and freezes the scene with a strobed LED flash lasting tens of microseconds
- Vision software segments each object, returns centroid, orientation and class, and stamps it with the encoder value at exposure
- The controller converts that stamp into a moving target, and the arm intercepts the product mid travel rather than waiting for it to stop

End effectors are usually venturi vacuum cups fed by compressed air, because suction grips a biscuit, a blister pack or a moulded fitting without a bespoke jaw profile. Bernoulli grippers achieve the same result without contact for wafers and thin film.

Nothing here resembles a hand. The geometry was chosen for stiffness and speed, and it ended up looking like a spider because physics preferred it that way.

#stemantics #robotics #automation #manufacturing #engineering

## Stats

- **Views:** 18,038
- **Likes:** 167
- **Shares:** 0
- **Comments:** 9

## Tags

automation, engineering, robotics, manufacturing, stemantics

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