Insect Walker v2

Dive in

Download the design in Ldraw here. I made it on a Mac with Bricksmith, but the file should work with other Ldraw software too.

This is a redesign of the first Insect Walker. Version 2 has a few minor improvements (see below), but the biggest difference is the design of the feet. In the current version they are simpler, lighter and equally effective.

After I had built version one, made the digital design, documented it and put it on-line, I looked at the video clip (the one below) with the two types of legs. Only then I realized that I had made a mistake. It was not the different design of the legs, but the fact that they were not in the same phase of the step cycle.

So, although the feet of the first Insect Walker look a lot more impressive, they are not more effective – which is what I had hoped.

I compared how much weight the two designs could carry. It turns out that version one weighs about 925 grams and can carry 275 grams at most (with 275 grams it almost comes to a stop). Version  two weighs about 650 grams and can carry about 525 grams at most. For the careful observers: the total weight of the machine plus the load in both cases adds up to about 1200 grams. It seems that the load-carrying capacity is mostly limited by the engine and the gear box, not the design of the feet. I am now very curious how it will behave with an XL power functions motor, which has twice as much torque. It can then go faster and perhaps have additional functionality – steering would be nice. So maybe there will be a version 3.

Getting the feet and legs to move in sync

While I was making the comparison, I found out that getting everything to work properly is really not easy. Firstly, although I had designed the machine, I found it hard to put version one back together and get it running. All the gears have to be placed exactly, with stress on exactly, as described in the manual.
Secondly, while the machine was running, I occasionally heard some load ‘ticks’ which turned out to be caused by the link chains skipping over one or two teeth on a gear. Also, one of the worm wheels was prone to skipping. So, the improvements address these problems.