[Dprglist] PID

[Murray Altheim]

Hi Rud,

The setpoint for the PID controllers is a velocity value. The basic
task is to accelerate to cruising velocity at 25% of the distance,
then slow at 90% down to targeting velocity to stop at 2m.

   0                              1m                             2m
   0          ->cruising                             ->targeting  0
   0              25              50             75         90  100
   |_______________|_______________|______________|__________|____|

Does that make any more sense?

Cheers,

Murray

On 30/09/20 1:50 pm, Rud Merriam via DPRGlist wrote:
> Hi,
> 
> I'm not understanding the log outputs.
> 
> At line 9740 the stbd motor has reached the 2m mark. The setpoint is set to 10.00 while earlier it was set to 50.00. I would think the setpoint should be the end position, i.e. 2m equivalent.
> 
> At line 9754 setpoint is not 0 and the error is 10.019. If it is at the end position the error should be 0. After that error is non-zero so outputs are generated which move the motors.
> 
> IMO the setpoint should be the number of steps (or equivalent) you want the motor to have moved. The error is the difference.
> 
> 
> -73 -
> *Rud Merriam K5RUD*
> /Mystic Lake Software/ <http://mysticlakesoftware.com/>
> 
> On 9/29/20 7:24 PM, Murray Altheim via DPRGlist wrote:
>> Hi,
>>
>> Addressing the hunting behaviour on the KR01 robot that we've discussed
>> previously (i.e., rocking back and forth about 1/8 of a wheel turn after
>> stopping), here's a full color (!) log of the journey:
>>
>> https://service.robots.org.nz/wiki/attach/PIDController/pid_bounce_log.html
>>
>> I may mention this in tonight's video discussion, thought to provide a link
>> here. It basically shows the encoder and PID controller output as the robot
>> accelerates to cruising speed then decelerates to a slow, targeting velocity
>> before attempting to stop at the 2 meter mark.
>>
>> Cheers,
>>
>> Murray
>>
>> ...........................................................................
>> Murray Altheim <murray18 at altheim dot com>                       = =  ===
>> http://www.altheim.com/murray/ ===  ===
>> = =  ===
>>     In the evening
>>     The rice leaves in the garden
>>     Rustle in the autumn wind
>>     That blows through my reed hut.
>>            -- Minamoto no Tsunenobu
>>
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> 
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-- 

...........................................................................
Murray Altheim <murray18 at altheim dot com>                       = =  ===
http://www.altheim.com/murray/                                     ===  ===
                                                                    = =  ===
     In the evening
     The rice leaves in the garden
     Rustle in the autumn wind
     That blows through my reed hut.
            -- Minamoto no Tsunenobu