5-axis hydraulic robot

It started as kind of a suprise. One day dad appeared in the drive-way with this thing. It didn’t have any control electronics with it. Only the skeleton and hydraulics.

Luckily it also had position sensors. We started working on it and soon found out that those sensors weren’t that easy to use. But after a while we managed.

The heart of the project was a 20MHz AVR microcontroller which controlled separate axis controllers. Each axis were independent and the position value was updated simultaneously for each axis by the master controller.

I don’t remember anymore how long we played with this thing, but the system had quite many iterations. The latest version used Compact Flash card to hold the trajectory. I wrote simple file system handler for FAT16 that understood one continuous file in the card. It was possible to write that file to the card with a PC and then let the machine run it.

There was also live communication to a PC over serial link. It was used to monitor how the machine was performing when it was running a trajectory. You could see the planned position and the real position in realtime. If I remember correctly I wrote the monitoring software with Qt. You could also tweak the parameters from PC.

One scary value was the main timer. You could speed up the trajectory running by adjusting a slider on a PC. I almost caused little damage with that slider. It was moving so fast that the machine yanked itself free from the bolts that anchored it to the concrete floor.

It was really fun project to work with.