hi guys (and any girls), ive been working on a picaxe robot arm code,
the problem i'm having is that the calculations required to workout the servo
angles to move the arm to any particular possition take so long thst the servo
movements are really jerky and smooth motion between 2 points is not really achievable,
originally i was using a 28x picaxe using lookup tables for sin cos and there inverses as well as squareroot.
I've now replaced this with a 28x1 with the intention of renning it at 16MHZ
(this wasnt possible with 28x because of servo command) i put the chip in the same board
and changed the resonator to 16MHZ and downloaded an identical code,
but noticed absolutelly no increase in speed when it should be 4x faster right?
am i doing somthing wrong?
ive since replaced the lookup tables with the 28x1's math functions
in search of a faster servo refresh rate and included the code for any
suggestions as to how to speed it up. So in summary I'm looking for any way to speed up the servo refresh rate involving either hardware of software....
on another note, the servos seem to glitch randomly, does anyone know a quick hardware remedy.
Reeally really appreciate any help im quite stuck
the problem i'm having is that the calculations required to workout the servo
angles to move the arm to any particular possition take so long thst the servo
movements are really jerky and smooth motion between 2 points is not really achievable,
originally i was using a 28x picaxe using lookup tables for sin cos and there inverses as well as squareroot.
I've now replaced this with a 28x1 with the intention of renning it at 16MHZ
(this wasnt possible with 28x because of servo command) i put the chip in the same board
and changed the resonator to 16MHZ and downloaded an identical code,
but noticed absolutelly no increase in speed when it should be 4x faster right?
am i doing somthing wrong?
ive since replaced the lookup tables with the 28x1's math functions
in search of a faster servo refresh rate and included the code for any
suggestions as to how to speed it up. So in summary I'm looking for any way to speed up the servo refresh rate involving either hardware of software....
Code:
symbol x=b0
symbol y=b1
symbol length=b2
symbol theta=w6
symbol lengthsquared=w13
symbol math=w12
symbol rotate=b15
symbol fingersadc=b7
symbol sholder=b16
symbol elbow=b17
symbol fingerscalc=b18
symbol wrist=b19
symbol fingers=b12
symbol fingercalc2=b20
servo 3,150
servo 4,150
servo 5,150
servo 6, 150
servo 7,150
setfreq m4
main:
readadc 3,rotate
readadc 0,x ;read x
readadc 1,y ; read y
readadc 2,fingersadc
;let b6=b7/20 ; potentially to help oppening fingers but romoved because it helped speed up
;x=x-b6 min 2
math= y*y ;calculate the length between origin and point
lengthsquared= x*x+math
length=sqr lengthsquared
b4= y*100/length ; calculate angle between x axis and point
gosub sine1b4
theta=b4
b3= 62550-lengthsquared/305 ; cosine rule to calculate angle between two arm lengths
gosub cosine1b3 ; this is angle for second servo
b4= sin b3*105/length ;sine rule to calculate angle between first arm length and strait line between 2 points
gosub sine1b4 ;this is the angle beteen first arm length and strait line between 2 pionts
b4=b4+theta ;ands the last thing to angle between the origin and the pint to calculate the first sevo angle
fingercalc2=fingersadc*14/51 ;i have a funny hardware setup for the figers and this sorts all that out
fingerscalc=fingercalc2/2+100
fingers=fingercalc2+150
elbow= 180-b3*5/6+90
sholder= 180-b4*5/6+75
wrist= fingerscalc + elbow + sholder
servopos 4,sholder
servopos 5,elbow
servopos 6,wrist
servopos 7,fingers
servopos 3,rotate
goto main
sine1b4:
lookup b4,(0,1,1,2,2,3,3,4,5,5,6,6,7,7,8,9,9,10,10,11,12,12,13,13,14,14,15,16,16,17,17,18,19,19,20,20,21,22,22,23,24,24,25,25,26,27,27,28,29,29,30,31,31,32,33,33,34,35,35,36,37,38,38,39,40,41,41,42,43,44,44,45,46,47,48,49,50,50,51,52,53,54,55,56,57,58,59,61,62,63,64,66,67,68,70,72,74,76,79,82,90),b4
return
cosine1b3: ;first 100 values are negatives
lookup b3,(180,172,169,166,164,162,160,150,157,156,154,153,152,150,149,148,147,146,145,144,143,142,141,140,139,139,138,137,136,135,134,134,133,132,131,131,130,129,128,128,127,126,125,125,124,123,123,122,121,121,120,119,119,118,117,117,116,115,115,114,114,113,112,112,111,110,110,109,109,108,107,107,106,106,105,104,104,103,103,102,102,101,100,100,99,99,98,97,97,96,96,95,95,94,93,93,92,92,91,91,90,89,89,88,88,87,87,86,85,85,84,84,83,83,82,81,81,80,80,79,78,78,77,77,76,76,75,74,74,73,73,72,71,71,70,70,69,68,68,67,66,66,65,65,64,63,63,62,61,61,60,59,59,58,57,57,56,55,55,54,53,52,52,51,50,49,49,48,47,46,46,45,44,43,42,41,41,40,39,38,37,36,35,34,33,32,31,30,28,27,26,24,23,22,20,18,16,14,11,8,0,0,0),b3
returnReeally really appreciate any help im quite stuck
Last edited:
