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Pythagorus, Kinematics, Broken Hips, Angry Neighbours

A project log for Inexpensive 3D Printed Full Size Humanoid Robot

I'm designing a super cheap humanoid robot platform. It is going to be the same size as an adult person.

dan-dwroboticsDan DWRobotics 07/25/2017 at 23:410 Comments

Small update. The last couple of nights I have been working on some new GUI sliders for the legs. The idea was to create a slider that would make one of the legs raise up at the hip and knee. I created three sliders one for each leg and one which controls both legs at the same time.

   I got reacquainted with Pythagoras and worked out that if trying to keep the hips and ankles level with each other they should contract by an equal amount( of degrees) whilst the knee needs to contract by double the amount(of degrees).

In theory I should be able to keep the legs upright whilst cycling up and down a crouch manually with the slider rather than merging between saved moves.

In it's most basic form, this is the essence of kinematics. Although there is much more work to be done on making and accurate mathematical model of the legs.

    This gives me a very basic ability to control the total 'crouch' by moving one slider up and down. By alternating crouch on each leg I can begin to build the rudiments of a walking gait. Although the hips need much more strengthening before they will rigid enough to do this properly.

     The below video shows me using the slider to control all 6 joints at the same time:

I thought it would be fun to throw some extra difficulty into the mix by putting it on carpet to see how it would fare.

  When the legs cut out completely this is due to the power supply I am using. It only provides max 4 amps at 12 volts so the legs sometimes try to draw much more, usually at an extreme crouch.

I am designing bigger, more rigid feet for it, that will also feature quad pressure sensing to enable autonomous balancing to stabilise the legs.

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