hello ,
i wanna control a pneumatic cylinder and i need to create a sinusoidal mouvement (the stroke must extends in and out) how can i do that ? i thought about the frequency gernerator
any one have an example about an electropneumatic asservissement ?
thanks
I am not an expert on this topic however I would start by looking at stepper motor solenoid valves to precisely control air flow to your pneumatic cylinder. The valve can then easily be controlled by a simple stepper motor driver and arduino micro controller setup. You can then use simple forward and backward stepper motor code to control your pneumatic cylinder with precision.
How big is your required stroke? You might be able to accomplish what you want with some gearing unless you already have your actuator.
If you already have a linear actuator just use a sin(theta) function and vary theta linearly
If you are doing this without a microcontroller let me know, you would likely need an oscillator circuit and a voltage follower opamp configuration
thanks for replying , i have thought about a part of what you said but i didn t get what you want to say about how the valve (solenoid ) can be controlled by a stepper motor can you explain more please ?
thanks again
thanks for replying
the stroke must be controlable (extends amplitude ) , i will use an arduino microcontroller with a relay but if there are better ways i m readdy to change it
what do you think which way is more simple ?
and i hope you can explain me more about the sin(theta) because the idea is exactly like you said but how can i do that function in real please?
Hi Amy,
Firstly have you acquired an actuator yet? If so, what kind?
Is this what you are trying to do? https://www.youtube.com/watch?v=SwYYysxuIfA
To control any motor via arduino you should open the IDE and click include to add in a new header file which makes motor/actuator control easy (e.g. servo, stepper, etc)
The math header file should have trigonometry functions like sin, cos, and tan.
To linearly increment you can just define a variable equal to zero initially (x)
to increase x by one you can type
x++;
or
x = x+1:
this should be done in a loop so that it increases in value by one every iteration of the loop.
To change the rate just change the scaling of x
sin(x*scalingfactor)
Let me know if you have any more questions
Hello again,
Pneumatic cylinders are usually controlled by air. For this you need to control the air you are pushing in and out of the cylinder. They are not really designed for precision sine wave movement however can be controlled by stepper motor solenoid valve to control the air flow going in and out.
A much better and more precise method is to use a linear actuator or linear rail controlled in exactly the same way by a single stepper motor.
Just look up arduino stepper motor on how to control it.
You can buy these off Ebay good luck
thank you very much it s very useful for me
about the actuator i will give what kind if it and exactly what i wanna make is shomwn in this video
https://www.youtube.com/watch?v=ilE2GfB0XPI
yeah you right but my problem with stepper motors and electric actuator is the low speed , ineed a very high speen for the actuator
I would check out the link below for ways to cause linear actuation.
https://www.servocity.com/motion-components/linear-motion
You can make or buy very fast linear actuators that work with stepper and electric motors. It really just depends on the gearing. The real limitation is weight and expense.
You could also make something similar to a locomotive engine which has a bar attached to a drive wheel to cause sinusoidal linear motion. https://en.wikipedia.org/wiki/Driving_wheel
So you want a servo controlled pneumatic cylinder setup.
These are readily available on the market.
https://www.youtube.com/watch?v=4hIlLzCneDg
https://www.enfieldtech.com/portfolio/accurate-force-control
it s exactly what i want
thank yuo very much
have a good day :)
thanks :)
have a good day
Glad to help. Good luck Amytech
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