Motor for back and forth motion at 800 RPM speed?

[Narendra1190]

hii,
i need to choose a motor for back and forth motion from 0 degree to 200 degree and back to 0 degree and so on...this task i want to perform for 800 times in a minute... which motor i can use for this application?plz help me.

 

[barry]

What do you want to move? A toothpick? An elephant?

There's no way to answer this.

Maybe a stepper motor. Maybe a servomotor.

 

[Narendra1190]

i want to move a very light weight pulley. torque is not a problem.

 

[BradtheRad]

There is the classic rotary-to-linear motion converter:

 

[barry]

There is the classic rotary-to-linear motion converter:

The op was looking for rotary motion; he didn't say anything about linear motion.

Still, we need to know more about your application. Like accuracy. The simplest solution would probably be a cheap DC motor and two limit switches.

 

[FvM]

The op was looking for rotary motion; he didn't say anything about linear motion.

The transmission would look a bit different, but I agree that a mechanical solution is most promising if the motion shall be constantly repeated.

 

[milan.rajik]

Size of the pulley? You want direct drive or belt driven? If you can use belt driven then use a flywheel fixed to motor (if dia of flywheel is larger then dia of your pulley then RPM of pulley will increase).

 

[Narendra1190]

Actually i m getting interrupt pulses from metal detector sensing a metal bolt which is attached to a pulley. That pulley is moving at 1400RPM. so i am getting 1400 interrupt in a minute.now i want to modify the design using these interrupt pulses for application shown in below picture.


here is the application i want to modify.

**broken link removed**


Stepper motor moves the white wheel which moves the pulley attached through belt.pulley is half size of white wheel. Stepper motor having 1.8 degree step angle.I need to move white wheel around 200 degree so that pulley moves little more than one revolution.

now. for first interrupt motor should move 200 degree forward and second interrupt it should move 200 degree backward and so on..back and forth motion...i think minimum motor 800 RPM motor required. so i m looking for a motor and motor-driver suitable for this kind of application.any kind of help is appreciated.thank you.

 

[milan.rajik]

I am getting invalid attachment. Zip and attach the file.

 

[Narendra1190]

sorry. u can see the image below.

 

[FvM]

Do you mean, you want to implement a motion scheme for the existing mechanics? It's now moving continuously forward but want to drive it forth and back?

Besides motor and drive electronics specification, you need also to check that the mechanical setup is prepared for the inertial forces involved with this operation mode.

Regarding qualification of a specfic stepper drive, you can sketch a speed ramp based on the maximum start-stop frequency and acceleration with the given moment of inertia and check if it's fast enough.

 

[Narendra1190]

Sir, i m using stepper motor.but i m not getting good speed.I am using Atmega32 MCU with ULN2003 driver.Supply to motor through ULN2003 is 12v.Stepper motor is having 1.8 degree step angle.
My code is below.

#include<avr/io.h>

#include<util/delay.h>


unsigned char v[]={0x09,0x05,0x06,0x0A};//stepper motor bit pattern for full step sequence Forward Direction

unsigned char w[]={0x0A,0x06,0x05,0x09};//Stepper motor for Reverse Direction

unsigned int k,l,m,n;                        


void main()                 

{

DDRB=0xff;

while(1)                  

{

for(n=0;n<50;n++)          
{

for(k=0;k<4;k++)         

{

PORTB=v[k];             

_delay_ms(3);            

}
}
for(m=0;m<13;m++)

{

for(l=0;l<4;l++)

{

PORTB=w[l];            ////Reverse Direction 

_delay_ms(3);

}
}
}

}

for less than 3ms delay motor is not moving properly and at 1ms delay its not moving.how can i optimizw the speed.?

 

[FvM]

for less than 3ms delay motor is not moving properly and at 1ms delay its not moving.how can i optimizw the speed.?

You need a constant current, high voltage step motor driver and probably a different step motor. Secondly acceleration and deceleration ramps (variable step rate) must be implemented.

 

[Narendra1190]

sir, i m not getting how to implement acceleration and deceleration ramps using c codes.

 

[FvM]

There are many ways. You can e.g. calculate a table of delay times for each step. Setup a step timer interrupt and load new timer values durng the ramp for each interrupt.

 

[Narendra1190]

hi sir, i tried acceleration and deceleration. I decreased timer count at each next step for acceleration and increased timer count for deceleration.by this way i got improvement in speed but only for long or continues rotation. i am not getting good speed for back and forth half rotation.help me.