I am in the process of designing and building a Drawing Machine from scratch using Picaxe 18m2's to control the stepper motors. The control signals from the Picaxes control L298N modules. These control Nema 17 Bipolar 200 step, stepper motors. At present I intend to use two stepper motors individually controlled with the possibliity of adding a third stepper motor and servo motor in future. The drawing machine is intended to produce cyclic patterns rather than specific images.
I have reached the point where I can control the speed and direction of the stepper motors, and made my design up using different modules, some homemade. I want the stepper motor to rotate fairly slowly in order for observers to see the patterns produced develop gradually. The problem that is becoming apparent is that at low rotational speeds the motors have pronounced judder rather than a steady rotational speed. Is it possible to reduce or even eliminate this judder at low rotational speeds?
The rotational speed is derived from using a potentiometer connected to b.3 to change the value of the delay w2 from Zero to 128.
The code I am using to control rotation is:-
I know I could do this differently say with Geared DC motors, but I have a number of old both used and new stepper motors and L298N modules available.
Also I am aware that these drawing machines are not new, but I wanted to design and build everything from scratch and not just copy others. Ideas on how to smooth out the rotation of the motors at slow speeds would be welcome. I could run the motors at a faster speed and gear the speed back, but I am trying to keep the design
as simple as possible.
Clockwork G8RIW
I have reached the point where I can control the speed and direction of the stepper motors, and made my design up using different modules, some homemade. I want the stepper motor to rotate fairly slowly in order for observers to see the patterns produced develop gradually. The problem that is becoming apparent is that at low rotational speeds the motors have pronounced judder rather than a steady rotational speed. Is it possible to reduce or even eliminate this judder at low rotational speeds?
The rotational speed is derived from using a potentiometer connected to b.3 to change the value of the delay w2 from Zero to 128.
The code I am using to control rotation is:-
Code:
Clockwise:
do
let PinsB = %10000000 'B.4 Energised
pause w2
let PinsB = %11000000 'B.4,B.5 Energised
pause w2
let PinsB = %01000000 'B.5 Energised
pause w2
let PinsB = %01100000 'B.5,B.6 Energised
pause w2
let PinsB = %00100000 'B.6 Energised
pause w2
let PinsB = %00110000 'B.6,B.7 Energised
pause w2
let PinsB = %00010000 'B.7 Energised
pause w2
let PinsB = %10010000 'B.7,B.4 Energised
pause w2
loop
Also I am aware that these drawing machines are not new, but I wanted to design and build everything from scratch and not just copy others. Ideas on how to smooth out the rotation of the motors at slow speeds would be welcome. I could run the motors at a faster speed and gear the speed back, but I am trying to keep the design
as simple as possible.
Clockwork G8RIW