Boebot shadow vehicle problem

zx1shadow

Hi guys , well iv been trying to get my boe bot to follow a piece of white paper, i used the example from the manuel of course but my boe bot insists on reversing constantly ,it does react when i put paper in front of it ,but it only tries to avoid it, any help would be nice.here is the code im using.





' {$STAMP BS2}
' {$PBASIC 2.5}
'

---

[ constants ]

---

kpl CON -35
kpr CON 35
setpoint CON 2
centerpulse CON 750
'

---

[ variables ]

---

freqselect VAR Nib
irfrequency VAR Word
irdetectleft VAR Bit
irdetectright VAR Bit
distanceleft VAR Nib
distanceright VAR Nib
pulseleft VAR Word
pulseright VAR Word
'

---

[ main routine ]

---

DO
GOSUB get_ir_distances
pulseleft = setpoint - distanceleft * kpl + centerpulse
pulseright = setpoint - distanceright * kpl + centerpulse
GOSUB send_pulse
LOOP
'

---

[ subroutine - get ir distances ]

---

get_ir_distances:
distanceleft = 0
distanceright = 0
FOR freqselect = 0 TO 4
LOOKUP freqselect, [37500,38250,39500,40500,41500], irfrequency
FREQOUT 8, 1, irfrequency
irdetectleft = IN9
distanceleft = distanceleft + irdetectleft
FREQOUT 2, 1, irfrequency
irdetectright = IN0
distanceright= distanceright + irdetectright
NEXT
RETURN
'

---

[ subroutine - get pulse ]

---

send_pulse:
PULSOUT 13,pulseleft
PULSOUT 12,pulseright
PAUSE 5
RETURN

SRLM

I suspect that the robot is reversing constantly because the pulseleft and pulseright variables are so close to the middle threshold that when the distances are small it is just about stopped, and any other value the pulse values cross the threshold to the other side and reverse the wheel direction.

To solve, I'd test with a higher setpoint value, and maybe play with the signs on the parts of pulseleft and pulseright.

erco

It's a little easier with a Scribbler, but with some servo-driving code additions, it will work: http://forums.parallax.com/showthread.php?133845-IR-Compound-Eye-from-RBB-4-and-Let-s-Make-Robots-(Video)&p=1042689&viewfull=1#post1042689