This is the sixth and hopefuly the most final android I will build. It will use the hip, foot and mostly the body structure from android 4, the control system will come from android 5.
The legs will use wiper motors, while the arms will use the linear actuators.
I will also take parts from android 3 as it has some nice motors that can be used for the wrists and some control electronics.
This time the legs will be made of 6mm plywood cut into the shape of the ‘profile’ of the legs, here are some of the pieces as I made them. The motor mounts:
The outside sections taped together for drilling:
All the parts together on the workbench:
Each part is painted individually with black emulsion. Here are the wiper motors attached to their mounts, again each leg will have two motors:
The sections will be spaced apart with 8mm threaded rod and locking nuts. Here is one half of one leg:
And all four parts laid out together. The legs are shaped to be less ‘boxy’ and slightly more styled looking. I may even cover the fronts with some vacuum moulded curved parts, although they are quite stong enough to work as they are:
As with the lest few androids the legs will have two vertical sections to make the top and bottom parallelograms. Here are the backs of the legs being painted:
They are also styled to taper in at the bottom and out at the top, so the android has thinner ankles and a fatter bottom. The two back sections:
Next, I had to dismantle android 4 to get it feet and hips, here are the original legs in pieces:
The original hip and foot assemblies next to the new legs:
And the body having a lie down:
The new legs are slightly wider so I had to widen the hips where they attach tot he tops of the legs:
They will fit together like this (all parts laid on the floor):
Here are the feet which are again widended to attach at the ankles:
Here are the legs in profile:
So, the next steps will be:
-Paint all the modified parts from android 4.
-Attach the legs to the hips and feet.
-Test bending the legs to see where the control electronics will fit.
-Strip and modify the body to make space for the main part of the controller, paint and reassemble.
I have had a quite a lot of time to work on this recently so I’ve made quite a lot of progress. Here are the legts assembled – they stand up now the push-rods are attached from the windscreen wiper motor assembly that will make the joints bend as the motors turn:
I have painted and reassembled the original foot and hip assembly from android 4. Here are the new legs attached to the original body:
and the legs in profile:
I’ve also made the body panels so there is basically a ‘box’ around the original body, this will allow the electronics to be housed and give it a similar style to the legs:
Some closeups of the construction:
I’ve made a curved from panel from hardboard, here it is all painted:
The space in the front is big enough for a mini itx PC motherboard so it may have an on board computer. In profile:
The space at the back holds the electonics, the original control system is mounted there along with some power distribution, there is plenty more space for some more:
So, it is 5’1′ / 155cm tall with it’s legs bent. Just as an idea of it’s size, here it is ready to do the washing up (maybe one day):
So far I can control the postion of the leg joints by sending RS232 (serial) commands from my PC, the sideways leaning action can be switched off an on, so the next stage is to measure the position as it swings from side to side and sync the leg movements to that position. Then it can pick up it’s legs in turn when the weight is on the other leg.
Also, I will be working on the arms – the mechanics and motors are already in place for the shoulders – to rotate and raise the arms outwards. The elbows will use two linear actuators on each to allow the forarm to bend at the elbow and also rotate. The wrist will use motors and control from android 3 to rotate and servos for the fingers. I may even get on a bit further with the android hand project.
Today I have added some ‘knee-caps’ and some bungee cords stretched over them, these act as damping for the legs – as the android is quite heavy it moves quicker when it bends it’s legs to crouch down than when it straightens them. These ‘springs’ act to compensate this a little – and it makes some visable difference as it’s weight shifts from one leg to the other:
I have started a new article here to show further testing and development now that the main construction is complete. I will continue to update this article as new pieces are made such as the arms and head.
Today I have done some more work on the arms. The upper arms were already made, today I have made the forearms which will contain motors to rotate the wrist:
and the elbow joints that allow the lower arm to rotate and bend:
Here they are all together with the hands laid on the ends:
Next stage will be to add two actuators to the upper arm to pan and tilt the elbow joint, also the hands and wrists will be detailed in the android hand article which I started some time ago.
Having spent some time testing and trying to make the android walk, I have decided to rebuild the hips. Currently the mechanism isn’t quite stong enough to pull it from side to side and the hips are also slightly crooked which means it gets stuck on one side. The new hips will be built from ‘box’ sections, the new spine will also be attached to them and this allows the body to have less solid wood sections making it more boxy too. This allows for more space inside the body and a more frame-like constuction.
Here are the new hip parts:
A sideways view showing the profile of the upper ‘spine’ – this matches the existing body sections at the front:
I have now put the new hips and spine on the legs, the horizontal rods are to hold the body and other parts:
There is a motor at the back that makes the android lean from side to side, this mechanism works quite well:
Here’s a close up, basically the motor ‘rota-shaft’/lever fits in a slot so as it goes around it makes the hips move one way or the other:
I have also fitted the original body panels back on, bolted the arms on (although they have no motors/mechanisms attached right now, or hands), and propped the head on top. So, it will look pretty much like this:
and the electronics are still in the back, the ‘sideways leaning’ control circuit is temporarily fitted to the far side at the bottom:
And it works!. A video of it walking can be found in the testing and development section.
As I can’t work on anymore further walking development until all the weight is on board, I have decided to crack on with the arms. I have redesigned and rebuilt the shoulder mechanisms:
The turning ‘roll’ motoion of each shoulder is actuated by a wiper motor, the rest of the arm will use the linear actuators. A lever links each motor to the rotating shoulder mechanicsm:
The inner and outer circle pieces are meachanically linked, the outer pieces with the brackets attached will allow the arm hinge upwards and downwards:
Have to rebuild the upper arms so they can hold an actuator, but the original foreams will remain on the ends…
Started to buld the upper arms which will rotate on the existing brackets so the arms can ‘turn’ at the shoulders and also lift outwards. In addition to this the inner ‘core’ of them rotates so that the elbow can rotate as well as bend. Each arm is made from 4 ’round’ sections:
The sections are all spaced apart on threaded rod:
Mostly the arms are now finished, although they have no control electronics they do have actuators that can be ‘manually’ postioned for now. Here’s one arm (less the actuators). Note: there’s a kind of channel in the outside of the upper arm for the actuator to fit:
Here’s the thing with actuators:
It has quite a lot of freedom of movement:
Here’s a close-up of the arm:
The arms use wiper motors in the body to ‘rotate’ at the shoulder:
The other three actuators allow the arm to ‘lift’ outwards:
Also to bend and rotate at the elbow:
Once the control electronics are in it will use the ‘swing’ of the arms to help it balance while walking. The wrists will have extra motors to rotate and once the hands are fitted they will be able to pan and tilt.
The actuators are a bit slow to move but they will at least allow accurate postitioning which will let me do some fun experimenting (picking different things up).