Gulliver, Our KHR-1 Robot, Gets A New Brain
We've been talking about it for a couple of months now, but with the RoboGames dates starting to come into sight on the horizon, it was time to really knuckle down and get ready to compete. So, on Wednesday we started to operate on Gulliver. Basically a stock Kondo KHR-1 robot that we built about a year ago, Gulliver has been gathering dust while we've been focusing on Mondai-Noid - our MANOI AT01.
Actually, we were kind of dreading the thought of having to deal with two different controller boards, especially since the RCB1 board used in the original KHR-1 seems rather primitive knowing what we can do with the newer RCB3 controller. The real kicker was when Kondo released the upgraded RCB3 firmware along with a new version of Heart2Heart.
The conversion from the RCB1 robot controller (2 of them actually) to the RCB3 controller turned out to be incredibly simple and straightforward. Not only was it easy to convert, it turned out that there were quite a few additional wonderful benefits that we didn't expect at all. We ended up kicking ourselves for having delayed the conversion so long.
It isn't quite 'plug and play', but it's darned close.
In a nutshell, you unplug each of the servo connectors from the existing pair of RCB1 controller boards in the KHR-1, one by one, being careful to mark each one with it's corresponding channel number. Unplug the rest of the cables and connectors, then remove the RCB1 mounting screws and the controller boards.
Mount the RCB3 controller board centering it in the middle of the robots back using the existing RCB1 mounting hardware. Remove the jumper on the right side of the RCB3 (4th set of pins), then install the small voltage booster module that kicks up the KHR-1 battery voltage of 6 volts to the HV range of 10+ volts. We used double sided tape to secure the booster module to the robots back.
Plug the servo cables into corresponding controller channels, one by one, double checking to make sure that they are oriented correctly, and plugged into the correct channel.
Load the matching H2H software into a new folder on the PC, and install the USB driver software to be able to communicate with the robot. Use the Window control panel -> System -> Hardware Manager to confirm which serial ports are assigned to your robot, and select the correct channel from the H2H pull-down menu. Power up the robot, and assuming that everything is working well, you should be off to the races.
The RCB3 takes up half the space of a RCB1. The rat's nest of wires is totally our fault. We plan to go back and clean it up as soon as we can carve a few minutes out of our schedule.
Trimming, and setting up the home position went very quickly since our robot was trimmed pretty well with the older controllers. We'll post some screen shots in a later post. From that point onward, we found quite a bit of unexpected 'joy'.
For example, using just the H2H3 application, you can pull in and convert existing KHR-1/RCB1 motion sequences so that they will run with the RCB3. We haven't finished converting all of our old motion files yet, but for the half that we have finished we've had no problem at all.
Then it turns out that using the Link functions, it's easy to set it up so that the robot will do things like squat down, then stand up, which is a huge help when we have to create a set of new motion sequences from scratch.
And - one more surprise - motion sequences designed for the KHR-2HV robot kit can be automatically converted to run correctly with the KHR-1/RCB3 configuration! That means that we will be able to use all those neat soccer moves!
What's next on our robot hacking agenda? Here's our current project list to get Gulliver ready for the June competition:
- Swap out the stock feet for the newer tub soles
- Replace the leg pitch servos with KRS-2350's for improved torque and performance.
- Add the PS2 gamepad remote control interface.
- Install the two additional DOF to the robots legs.
- Rough out the body shells and costumes
Of course, like the Hydra, by the time we get almost finished with one project, another two will pop up to make demands on our limited time.