(inverse)-kinematics

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Re: (inverse)-kinematics

Postby TooManySecrets » Sun Aug 11, 2013 4:47 am

Hey good idea with the android device. But i might have a less complicated solution.

A Raspberry Pi can run linux and it can run python. Why not just use that to talk back and forth from the servator and ps2 controller.

A Raspberry Pi is also low power and lighter then a android phone.
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Re: (inverse)-kinematics

Postby klims » Thu Aug 15, 2013 11:10 pm

rpcook wrote:[*]I don't know what the communication protocol is from the PS3 controller (apart from Bluetooth), but I'd be very surprised if it's a low baud rate serial interface, which I think would preclude direct communication between the controller and the (current) Bluetooth module.[/*]

I haven't tried it yet, but I'm going on the assumption that something like this will work
http://barrettsprojects.wordpress.com/2 ... nstration/
Serial in commands from the USB host module which interprets the PS3 controller commands.

rpcook wrote:[*]Given that the stock build of software in the Servotor32 makes the onboard memory about half full. Implementation of full-robot IK code might be either too large to fit onboard, or the processor speed would limit the speed of the IK code such that Hexy's speed would be limited.[/*]

I have compiled the hexapod code shown in the tutorial I posted with servotor32 file necessary to move servos and it fits on the board. I haven't been able to try it yet to assess the quality of the motion performance, so you could be right about the speed of Hexy being limited.
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Re: (inverse)-kinematics

Postby klims » Wed Aug 28, 2013 10:28 pm

I had some limited success with doing the IK on board.

It all works as expected, but Hexy jolts around as he moves. The actions are not as smooth as I had hoped.
I think this is due to my fundamental misunderstanding of how the other hexapod makers were achieving smooth gaits while doing the processing on board. From what I gather looking at the lynxmotion kits they always have a servo controller board that handles the the servo movement and interpolation/smoothing while the brain handles the IK calcs, which is essentially what the servotor32 and PC running PoMoCo do...
I'm messing around with trying to do some kind of interrupt driven servo interpolation, but I'm not confident in that solution.

I've ordered a MK808 Android TV Stick on which I plan to install PicUntu and just run Michal's PoMoCo 2.1
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Re: (inverse)-kinematics

Postby roboalchemist » Thu Aug 29, 2013 3:17 am

You had the same idea I did! One of my many side projects is to get a ROS distro rolled out for MK808's and sell them on the store ;)

I'm *super* excited for early next year, when their new processor comes out with OpenCL support., i.e. hardcore machine vision on a MK808-like stick.
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Re: (inverse)-kinematics

Postby TooManySecrets » Thu Aug 29, 2013 7:36 am

Those TV sticks are like amazing, i have a bitcoin mining rig running of a Mk802iii on Picuntu.
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