Here a short summary of my personal impressions after the first test drive:
* Wheels are to heavy - they need to be a lot lighter. Most of the power of the motors gets lost to turn wheels.
* Casing: I guess I can design the next casing at least 1/3 smaller - most probably I will decrease the heights - so more surface for solar panels.
* Steering: I had no encoders installed - a must to drive a straight path. I see only induction encoders as a possiblity (or generator power?). Optical encoders might get covered by regolith...
* Swinging: During acceleration and decceleration the inertial forces let the body swing fwd/aft. That might be a handicap for video. Dan Smith suggested a dragging glider/roller to avoid swinging. This would be a very easy solution, but I will not integrate it right now - maybe in a later version?
* Control Commands: Currently I send one command after the next one to the rover - (eg. first CW/CCW, then: speed "150", then left wheel). For future control, the commands needs to be bundled and executed "simultanisously" - e.g for a left turn, 5 seconds:
Command pack 1 is:
(RW, CCW, 150; LW, CCW,100; 5s)
Send (Pack 1) to rover
Get feedback of command pack (recieved, checksum,...)
Send execute command
Start watchdog on rover (to interrupt movement in case of fail function)
Get confirmation of accomplished movement
* I need to get rid of the cables
Moreover, it was very easy to get it to drive, hardest thing was to get the wheels. It is very flexible and easy to control.
Has someone a good idea for the wheel design - I've one in mind, but I'm open for any proposal - I'm also thinking about using composite materials? - It will be a hard job to top Jörgs design - but I think I stay more simple.
I'll open soon launchpad soon for the rover control software - either C or C++.
Currently I'm working on the wifi connection, I need to get wifi dongle running and then I should be able to do first cross country tests. Hopefully until end of Jan. Then I will integrate the elphel cam. Shouldn't take me more then one month - maybe earlier.
So I hope to start with fineadjustment and getting closer to a nice looking and full featured rover version soon. If someone whats to help - help is welcome -
Some tasks I will open in our wiki as soon I've a better idea about I what we need:
a power/motor/heater/servo controller with an USB1.1/2.0 interface
a wifimodule with USB2.0, atheros chipset, 250mW output - can be off the shelf too, as long all drivers are opensource and it's possible to get them to run under linux.
Sounds interesting to you? Then contact me.
-happy new year to you all
tobi