Review

In review I feel I should address why I originally undertook this challenge. The task was deliberately very short and not hugely complex (by that I mean in comparison to high level robots like PR2). The idea being I could fit the build into a weekend and the complexity was reasonable enough to not get overwhelmed by it. There were a few main reasons why I set myself this challenge

1 – I to get into the habbit of documenting well and sharing with a community.

Quite literally I wanted to blog with worthwhile and interesting project. Before I would note things down engineering style, very rarely photograph any thing and I had never uploaded a video to youtube before. I wanted to change my style due to how useful I had found other peoples blogs. I could always find a good how-to, some interesting hidden information, an inspiring project or simply for entertainment.

I found that after the after the first few posts I got into the swing of things and it became easier. I also shorted the posts and detailed just the bit I was working on at the time. I quite enjoyed it and got over the hurdle of ‘it will take too long to setup now in the middle of a project, ill just do it later’.

2 – I wish to tame my inner perfectionist

I quite often find that my projects go quite slowly for two main reasons. I try to design the perfect item before starting, which leads to a complicated design which will take forever to implement. Secondly I always want to make the current bit of the design perfect before moving on. This leads to constant re-design when the next part of the design in order to be perfect requires to first bit to be changed / re-written.

This project forced me to change my design strategy putting time as the most important commodity not quality. The basic strategy was to go from start to finish as fast as possible ending up with sketchyest only just working first version with minimal features. Then to take the first version and fix/improve and upgrade the design based on all the facts I had learnt in build the device.

I feel that the project gave me a great push into speeding up my own design process and not being constrained by perfection and from that perspective the project was an amazing success.

Going forwards

With the effort investing in getting the robot built I am not going to give up on it. I plan to finish continue to get the robot up and running. In keeping with the spirit of the original brief I will keep a record of time and try to get it walking as fast a possible. At the end I should be able to look back and see how long it actually took and really review the entire journey from start to finish.

This must have been done before so a quick google turned up exactly what I need. http://principialabs.com/arduino-python-4-axis-servo-control/. A bit of soldering and some testing the python code is able to control a few servos.

I am going to continue this another weekend, I do have 2 hours remaning on the clock but due to being very tired now the 2 extra hours wont help.  I will defiantly be finishing this off over the coming week so stay tuned for some more robotic action.

Completeted robot structure

The robot is now built !!!! It took at lot of hardwork but it is finally standing assembled and ready for programming. The good news is able to stand freely as in the photo. The bad news is it does the splits when the thighs are parallel to the ground.

I think the splits are due to the hips being very very wide. I will defiantly shorten the hip brackets in the future and possibly completely re-design that bracket to move the thigh servo into the hip area.

Now to program the robot in the little time remaining …. ahhhhhhhhh

With a basic flash test done its on the building the whole robot.

The first leg is constructed.

The first leg constructed !!!!!

Now its built I am very concerned how far the first 2 hip servos stick out. I think that the servo will struggle trying to support the whole leg. It looks like its going to be all or nothing at this point as there’s no time for redesign.

Going to pause the timer now,  I’m off to town to see my lovely girlfirend play a violin gig with her friends. Back in a bit

parts to cut

parts cut

And here is the first bracket constructed. Its a bit rickety and the wholes dont line up perfectly but its still works, whoo. Now to construct the rest!!!

first bracket fresh of the production line

A bit of cutting and drill later I get a completed chassis which looks pretty good.

Now to see if everything fits. The servos sit snugly with plenty of space for the arduino board in the middle,  jobs a good’n.

Next to start chasing the leg parts.

Brackets produced and ready to print !!!

This is the first large job my printer has done, the print file generation too around 30mins and the print time was due to take 10 Hours!!!!! So I setup the printer and headded for bed, dreaming of the nice new brackets awaiting me tomorrow morning.

Disasterous warping on the printing has ripped the print appart.

I got up for a drink of water during the night and went to check on the print. The print had torn itself appart, the parts had warped so much that they were much higher than the nozzle. Then when the nozzle had tried to transition from one bracket to the next it had drivent the nozzle through the warped plastic and ripped the bracket completetly off.

With 13hours still togo all is not yet lost. I will switch to manualy building some metal brackets and ask for a favour on a friends laser cutter. Hopefully still leaving enough time to code up the walking.

import_stl(“Servo BracketOutsideLongV1.1.stl”);

translate([10,10,0]) rotate([0,0,180]) import_stl(“Servo BracketOutsideLongV1.1.stl”);

translate([70,0,0]){

import_stl(“Servo BracketOutsideLongV1.1.stl”);

translate([10,10,0]) rotate([0,0,180]) import_stl(“Servo BracketOutsideLongV1.1.stl”);

}

bracket = “Servo BracketOutsideShortV1.1.stl”;

translate([0,70,0]){

import_stl(bracket);

translate([10,10,0]) rotate([0,0,180]) import_stl(bracket);

translate([70,0,0]){

import_stl(bracket);

translate([10,10,0]) rotate([0,0,180]) import_stl(bracket);

}

}

However when I try to produce the final stl it throws the following error :

ERROR: Illegal polygonal object – make sure all polygons are defined with the same winding order. Skipping affected object.

Its quite frustrating at the it compiles and visualises fine but throws an error on build. Guess Ill just have to find another way to combine stl files for printing.

Anyway on a lighter note, off out for a nice meal at a chinese restaraunt before starting back on this a bit later.