Been working on this in some form for a while now. College and life have been eating into my time lately so I was happy to have a little time to work on it.
Ender is comprised of 12 HSR5990TG, 6 HS-485HB, and a HS-422 for the head. The servos are all powered off batteries and a BEC from Hobby king (5990TGs are run direct from the battery). Servos are controlled by a SSC-32 which is in turn controlled by a BotBoarduino which is controlled through an XBEE and programmed with an AVRISP MKII so I don’t have to disconnect the XBEE. All of the frame elements are SES except for the board carrier which I machined from Acrylic.
I still need to do:
Install an on off switch
Mount the batteries
Secure wires better
Remove more compliance from joints by adding layers of scotch tape to fill gaps.
Machine new Board mounts from Aluminum with a hole for the programmer. (The acrylic has cracked already.)
Add some springs to preload certain joints
Find someone in/near Gainesville, Florida to battle!
I’ve figured out the IK for the legs but at the moment I’ll probably go with parametric sequences where as I generate some sequences and determine valid deviations from each frame of the sequence. I did this for an earlier version to allow for dynamic changes to heading and it worked fairly well. At the moment I’ve just got some simple code to relay commands from a terminal to the SSC-32 and an servo initialization which just turns on the servos and sends them to the positions in the photos. I’ll probably take a encoder and create a little controller with 19 switches so I can control each servo with the encoder then read out the final positions off the SSC-32. Hopefully that will facilitate making sequences. If it doesn’t work out well I’ll probably try and implement the IK since I’ve never gotten the HMI Interface to work properly. My girlfriend just began med school today so I’ll see if we cant get some simple motions together by Monday or so.
When I reamed out the holes in these brackets I made them slightly too large so it created some compliance. I found that wrapping some scotch tape around the bottom axle post (of the HSR-5990TGs) and bending the mounting brackets inwards removes most of this. If you have a more permanent or effective method to do this I’d be very interested to hear it since scotch tape isn’t the most elegant…
I’ll probably also add some Loctite to the screws since I’ve had some vibrate out on me already. I’d like to remove the majority of the compliance and then preload the servos to try and help with gear slop it’s an uphill battle though.
