This thread comes about to chronicle my experimentation with an SES compatible leg based heavily on the leg innerbreed has designed and built for his quadrapod. I’ve been studying his design very closely and have come up with a 5DOF SES based design that I believe gives at least the same flexibility as his custom leg, albeit apparently with two additional joints.
I’ve been working more on my SES compatible design of this leg. I still can’t get the same flexibility with a 3DOF version though. However, my SES design appears to allow some interesting movement possibilities, depending on how I calibrate the joints.
Right now, I have the first 2DOF (hip) calibrated in the standard way, with the usual +/- 90 degree range from center (“C” bracket pointing straight out from the servo). The change in calibration comes in the pair of knee joints. The first knee joins have 0 position at 45 degrees from center. The end effector is the rotator for the wheel/foot. That’s 5DOF total. For a quadrapod, this would require a total of 20 servos just for the four legs, but I believe the flexibility of this design warrants it.
I have one leg almost completely reassembled now and am anxious to build the first right leg and attach the pair to a body for further testing. Right now, I am also considering the possibility of building up a Tri-Pod using this leg design, for testing and something completely different.
I have an Arduino, using a semi-custom servo library, controlling the first left leg. I will have to get a few more parts, including more servos and more brackets. I want to use HS-645s throughout in the final build. I just like the idea of having metal gear servos in my robots, and the HS-645s are also perfect for conversion to Open Servos. I’m kicking around the possibility of dedicating a small microcontroller, such as the Arduino or other similar board, to each leg and sensors attached to the leg, with master control coming from a board such as the BeagleBoard or similar. I think this is the type of application where an Arduino, or other Atmega based board, would really shine.
I’ll take some pictures after I have the leg back together again (after the last of the design changes) and post them.
I have one left leg completed except for the motor. I have not decided how to mount the motor yet, but there seems to be just one workable method. I may remove one of the hip joints at some point as I am not convinced I need it. If I keep the second hip joint, I think I will mount it differently to get the leg closer into the body.
I needed to see how the leg works, so I pressed W.A.L.T.E.R. into service and attached the leg to him. Now I can better see how the leg will really work and can actually take some pictures of it in various positions.
I did quite a bit of tinkering with the leg last night, so am getting more comfortable with the new design and what it is capable of. I am using my Arduino to control the leg.
I’m talking about the motor that will drive the wheel at the end of each leg. There seems to be only one workable mounting without doing some major redesign of the leg.
i see. i know what you mean now. i thought it was that.
well cant wait to see pics. its always interesting to see ne SE designs. i can stop thinking of new ideas and combinations for the SES.
well its that time of year and with everything the way it is at the mo i have stopped working on my projects, but once things pick up i should be introducing the next phase of my stalker project. lynxmotion.net/phpbb/viewtop … 1&start=45
