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Subject: 
Re: Subtasks quitting before completing
Newsgroups: 
lugnet.robotics
Date: 
Mon, 9 Nov 1998 21:19:53 GMT
Original-From: 
Nancy Gold <NANCYG@SGIspamless.COM>
Viewed: 
6301 times
  
Lageson, Tom wrote:

> If my robot triggers a touch sensor and before it completes all of the
> commands in that group of commands that same touch sensor is hit again, the
> RCX gets confused and starts doing some unplanned and unexpected movements,
> never regaining its original program state.  How can I program to accomodate
> this event?  Also what happens if the RCX sends conflicting signals to the
> motors, how do you know which event or subtask has precedence?

This weekend I built a 4x4 rover with two front bumper sensors. I was faced
with the problem
of both sensors triggering at the same time. My fix was to set the counter to 1
and add a
stack controller to check the counter before turning the rover.

This worked except that I had a deadlock condition. I tracked it down to a
sensor triggering
for too short a period of time and the sensor commands not finishing. The fix
was this:


Release:
Add Counter
Check Counter = 1
On True: Reset Counter, Perform Manover
On False: No Action

Press:
Reset Counter (vital to avoid the deadlock)

The worst thing that can happen now is a right turn command overriding a left
and vis versa.
Not a problem.

After several hours of testing there are no funny states and the rover never
hangs.

--- Nancy



Message is in Reply To:
  Subtasks quitting before completing
 
I saw some posts during the last three days about subtasks quitting before completing. I never saw a solution, so I will re-ask the question. If my robot triggers a touch sensor and before it completes all of the commands in that group of commands (...) (28 years ago, 9-Nov-98, to lugnet.robotics)

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