Thursday, 3 November 2011

Delta robot and laser cutting

At another of our HackLlan meetings, and in preparation for the show-and-tell (provisionally booked for Sat 26th November, on the same day as the Llangollen Xmas Festival) we've had the laser cutter out, busy making and preparing a number of different projects.

First up is a simple three-servo delta-robot.
This robot will be programmed with a script to perform repetitive tasks such as pick up, move, release an object. There are no plans for any further  intelligence to be programmed into it at this stage - but perhaps could be used as a project for any follow-up workshop from the show-and-tell session.

The photo above shows the main structure with the servos mounted on it at 120 degree intervals. Slots were cut into a round disk, to allow the servo heads to move through 180 degrees, perpendicular to the base. The servos were lined up by placing their corners on top of some small cross-hairs etched into the base and stuck down with double-sided tape (in the final version we'll use permanent plastic cement, but for now we may need to move them around again as development continues!)

There are three legs, each made up of three lengths of acrylic.
The "hip" joint - the part that connects to the servo - is a single piece with a large circular head (for connecting to the servo horn). The lower part of the leg - from the "knee" to the ankle - is made up of two pieces connected either side of the top piece.

We're still thinking about how to make the joints, as the "ankle" joints need to free-moving in all axis directions. Someone suggested hobby-sized ball joints (like those found on remote control cars, helicopters etc). A cruder (but easier and cheaper) solution might be to simply use elastic bands to make the joints....