rgordon
Here is a gadget that may help some that are using motors instead of servos for motion control. Looks interesting.
Here is a copy of the Product Description:
"Kangaroo x2 adds self-tuning feedback motion control to your Sabertooth or SyRen motor driver. It can be used with quadrature encoders or potentiometers to provide position or speed control. It supports one or two feedback channels.
Feedback control has always been highly desirable for mechanical systems. Being able to tell your device to move an exact amount, at a specific speed or to a certain position, and have it reliably and repeatably do so, regardless of the load or disturbances, has obvious benefits. However, PID and other controllers have to be carefully tuned to get acceptable results. Feedback tuning is difficult, time consuming and requires advanced math and physics knowledge.
Kangaroo x2 is the first self-tuning controller in its class. Instead of requiring you to measure, model and calculate the system, the controller itself will figure everything out after a few switch settings and button presses. In the time it takes to get a tasty snack, you can come back to a perfectly tuned system ready to accept your commands.
Instead of requiring you to use a microcontroller to do closed loop control, Kangaroo x2 works from analog and radio control sources as well as microcontrollers and computers. You can, for example, use it to build that two horsepower R/C servo you've always needed as the final piece of your doomsday device. Just remember who helped when the vaporizing starts.
During operation, you can command speeds, positions or combined commands like "move to 37 inches at a speed of 4 inches per second." You can also have the Kangaroo x2 report back speeds and positions while it is running. A mixed mode allows for unstoppable mobile robots with differential drive or tank style steering.
If you need to get your product under control, Kangaroo x2 is the best way to do it. "
@Lumpy> Thanks for the reply Lumpy. Glad you got it to work.
Do you have any pictures or videos that show how your dome motor is mounted, how the HotPot is mounted, and what you are using for the dome rotation bearing on your R2?
So the Kangaroo x2 board, used with a Sabertooth 2x12, would allow you to control two dc gear motors just like a servo? Will it allow the motors to be positioned to any particular spot in a 360 degree circle or will it be limited to 90 or 180 degrees of travel?
How would I use/control the Kangaroo X2 with the EZ_B?
Rex
:O I think I'm going to add this to my project. I haven't spend much time on my robot in a while and this got the fire back on. I've been looking for something to control and measure the speed for a while now and I think this is the solution.
The plan is to run it in speed mode and control it manually rc style. I might go for serial control in the future, though I'm not sure yet what sensors I'm going to use. Probably some kind of quadrature encoder that I'll build, I'm thinking optical. Research is being done
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I'll keep you guys posted on this.
@budel0 That is great! I'm also thinking of buying a couple of these to try out. But maybe after Christmas.
@Lumpy Hope you can shed some light on the questions asked in post #11 above when you get the chance. Thx
@rgrordon I had some mail today.
I have to say... They're extremly fast... I ordered it last tuesday. For $2,- international shipping this has to be a personal record with ordering stuff from the US.
Anyways... I still have to find some kind of sensor to use as feedback. Any ideas? I was thinking something about an optical quadrature encoder, but I haven't been able to find any that will fit or is affordable.
Until then I'll keep searching.
@budel0
I have read through the manual and it really does a lot of neat things. Everyone that uses Sabertooth drives should take a serious look at this little jewel.
KangarooManual
@dschulpius (Dave) You could use these to control high torque DC Gear motors for your B9 robot arm joints just like servos. Using servo signals from the EZ-B.
Agreed! I'm looking very close at this. Thanks for the heads up.
I'm watching this , since I have that happen bridge saber tooth 2 X 12 for jarvis.
Hey ! ( Firstly, sorry for my poor english level, I'm a French student ) I'm having trouble with my kangaroo x2 : It works pretty goods in " independent mode " ( switch 4 : ON ) I send commands as :
printf "1,start"; // initializing the motor 1 putc"0x0D"; // replaces the requisite "enter key" printf "1,s50000"; // rotate the motor putc"0x0D"; // replaces the requisite "enter key"
And it works ( I'm using CCS v4 ), I communicate by a serial port ( 9600 baud, 8 bits, N parity, 1 stop )
But my problem is that I can't control my motors in " mixed mode " ( switch 4 : OFF ) I have to send commands as :
printf "D,start"; // initializing the two motor putc"0x0D"; // replaces the requisite "enter key" printf "D,s50000"; // rotate the two motor putc"0x0D"; // replaces the requisite "enter key"
But nothing happens. I tested a lot of things ( "D" or "d" , re-tuning the system, put some delay between the initalization and the speed command, knocking the robot, ... ) but I'm still in trouble.
If someone has an idea, I would really appreciate your help ! I'm using Kangaroo + sabertooth to control a robot ( see the picture ). It's for a robot contest. Thanks for your time !