Thread: CANJaguar vi's
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Unread 18-04-2010, 00:13
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Re: CANJaguar vi's

Quote:
Originally Posted by apalrd View Post
Do you honestly need to run any code faster than 50hz?
Need to? No.

Quote:
Originally Posted by apalrd View Post
The radio packets are timed to aprox. 20hz,
I believe they're 50Hz.


Quote:
Originally Posted by apalrd View Post
so anything faster than that is working off old data.
The point you are trying to make is a valid one, but your argument is not complete as it stands. When evaluating the frame rate for a closed loop digital control, it's not just the update rate of the set point that must be considered. The dynamics of the plant must be taken into account also. In this case, the response of the wheel velocity is likely much less than 50Hz, due to its mass (and the mass of the robot as long as the wheel is not slipping).


Quote:
Originally Posted by apalrd View Post
I have no loops running faster than every 20ms (50hz), most run at 40ms, and have no problems with PID timing at that rate.
You probably know what you are doing and have well-written code. Closing the loop in the Jag is more forgiving because the loop closure is immune to programming errors in other areas of the code that could cause realtime overruns - errors like I see discussed quite often here on Chief Delphi.

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