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Hello Steve,
Monday, February 9, 2004, 8:55:11 PM, you wrote:
SH> In lugnet.robotics, Philippe Hurbain wrote:
> > YAL: Yet Another LegWay
> > =======================
> >
> > Here are some details of my implementation, using two regular light sensor to
> > monitor YAL inclination.
> >
> > The [<http://www.philohome.com/yal/yal1.c code>] is a simple PID algorithm
> > implemented in BrickOS, direct translation of
SH> Hey Philo,
SH> I was just looking over your code, and I think if you change this line:
SH> pid = (Kd * err_diff + Kp * err + Ki * err_int) /3000l;
SH> to something like this:
SH> pid = (Kd * err_diff + Kp * err + Ki * err_int) /3000l + ForwardOffset;
SH> then when you change ForwardOffset (via remote control code) the robot will
SH> start to go forward (or backward, if it's negative).
SH> The ForwardOffset could be between -255 and 255 (I'm sure you don't want it
SH> quite that big)
SH> Steve
Or, you could just alter the original offset that is calculated when
you first turn it on. I used this method to get it to move forward and
back. Then it's easy to get the robot to rotate by implementing one of
the PID controllers for each of the wheels with opposite offsets.
Allen
--
Best regards,
Allen mailto:Kaptain.korolev@ntlworld.com
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> > Hey Philo,
> >
> > I was just looking over your code, and I think if you change this line:
> > pid = (Kd * err_diff + Kp * err + Ki * err_int) /3000l;
> > to something like this:
> > pid = (Kd * err_diff + Kp * err + Ki * err_int) /3000l + ForwardOffset;
> >
> > then when you change ForwardOffset (via remote control code) the robot will
> > start to go forward (or backward, if it's negative).
> > The ForwardOffset could be between -255 and 255 (I'm sure you don't want it
> > quite that big)
>
> > Steve
>
> Or, you could just alter the original offset that is calculated when
> you first turn it on. I used this method to get it to move forward and
> back. Then it's easy to get the robot to rotate by implementing one of
> the PID controllers for each of the wheels with opposite offsets.
>
> Allen
Hi Steve and Allen,
I already tried what you suggested, but I had only mixed results: either too
little moves or unstable and uncontrolable ones. Perhaps also my PID
coefficients, determined by trial and error, are not so good...
I'd like to have more time to tune all this!
Philo
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Hi Philo,Steve and Allen.
I've made a YAL right after reading the articles of you all.
It's great and very fun.
After tuning some papameters, it is working so well.
My Lego has been in a dark corner of my room so long time.
New BrickCC/BrickOS help me to follow up all procedures easily.
But, I don't know about "remote control code" !
> > > pid = (Kd * err_diff + Kp * err + Ki * err_int) /3000l + ForwardOffset;
> > >
> > > then when you change ForwardOffset (via remote control code) the robot
Please let me know and try to control this Legway in better way.
Kitak.
ps. I've wated for 10 days to get a admission for posting...;
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I’m lazy . . . would someone please write a version of the program that works
with the LEGO remote control? Using the remote control is cooler than driving it
with a flashlight. And with a flashlight you can’t make it turn.
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In lugnet.robotics, Jordan Bradford wrote:
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I’m lazy . . . would someone please write a version of the program that works
with the LEGO remote control? Using the remote control is cooler than driving
it with a flashlight. And with a flashlight you can’t make it turn.
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Okay, I tried writing it anyway. It doesn’t work, and I think it’s because I’m
not changing the motor speeds. All I’m doing is changing motor directions. Help
me out, please, since I spent the time to install BrickOS in BricxCC and learn
the remote.h and dsound.h APIs. Thanks!
#include <conio.h>
#include <unistd.h>
#include <dmotor.h>
#include <dsensor.h>
#include <dbutton.h>
#include <remote.h>
#include <rom/lcd.h>
#include <dsound.h>
int directionA, directionC;
int remote(unsigned int etype, unsigned int key)
{
if(etype == LREVT_KEYON)
{
switch(key)
{
case LRKEY_BEEP:
dsound_system(DSOUND_BEEP);
break;
case LRKEY_A1:
directionA = fwd;
break;
case LRKEY_A2:
directionA = rev;
break;
case LRKEY_C1:
directionC = fwd;
break;
case LRKEY_C2:
directionC = rev;
break;
case LRKEY_STOP:
break;
}
}
return 1;
}
int main(int argc, char **argv) {
long offset;
long err, err_diff, err_int = 0, err_old;
long pid;
int Kd = 210, Kp = 180, Ki = 10;
ds_active(&SENSOR_1);
ds_active(&SENSOR_3);
msleep(20);
offset = (long)SENSOR_1 - (long)SENSOR_3;
cputs("yal1");
sleep(2);
err_old = 0;
lr_init();
lr_startup();
lr_set_handler(remote);
while(1)
{
err = (long)SENSOR_1 - (long)SENSOR_3 - offset;
err_int = err_int + err + err_old;
err_diff = (err - err_old);
err_old = err;
pid = (Kd * err_diff + Kp * err + Ki * err_int) /3000l;
if (pid > 255) pid = 255;
if (pid < -255) pid = -255;
if (pid < 0)
{
directionA = rev;
directionC = rev;
pid = -pid;
}
else
{
directionA = fwd;
directionC = fwd;
pid = pid;
}
if (pid < 5)
{
directionA = brake;
directionC = brake;
}
lcd_int(pid);
lcd_refresh();
motor_a_dir(directionA);
motor_a_speed(pid);
motor_c_dir(directionC);
motor_c_speed(pid);
if(PRESSED(dbutton(), BUTTON_PROGRAM))
{
motor_a_dir(brake);
motor_c_dir(brake);
ds_passive(&SENSOR_1);
ds_passive(&SENSOR_3);
cputs("stop");
msleep(300);
while (PRESSED(dbutton(), BUTTON_PROGRAM));
motor_a_dir(off);
motor_c_dir(off);
cls();
lr_shutdown();
return(0);
}
msleep(20);
}
}
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Some other things:
-Is there any reason the Prgm button is being used to stop the program? Why not
just press the Run button again, like in the normal firmware?
-How can I make
the Stop button on the remote do what the program currently does when Prgm is
pressed? Maybe I’ll cheat and use a goto.
Thanks again!
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