Hello everyone,
what i need is a really slow Servo Motor.
It should work at 0,5 Nm Torque continuously and also has to be work between 0,03 Degree/Second to 5000 Degree/Second.
So does anybody have an idea how to find such a motor ?
I dont want to use gearboxes because it will cause to fail my test results.
Thanks for any help!
Sincerly
kaanoz9:
what i need is a really slow Servo Motor.......
I dont want to use gearboxes because it will cause to fail my test results.
How could a gearbox cause test results to fail?
What do you mean by "Servo motor"? Maybe post a link to one that is not slow enough so we know exactly what you are talking about.
In this Forum "servo" usually means one of these
...R
Thanks for reply,
i thought the gearboxes can mean lost of way between their teeths and it wouldnt be so smooth or continuous Motion. If i am not correct please tell.
I do not know what kind of a motor i mean but i need really low rpm s and want to controll it with arduino.
What i look for is not like a Hobby Motor.
I want to use it in a test bench for ball joint friction investigation.
Gears do give rise to backlash but that should only matter if the direction of motion is reversed. A toothed-belt can be used to provide speed reduction without backlash.
It would be a great help if you can describe in some detail the project you are trying to build and how the motor must be controlled to perform the tests.
You mention a speed range from 0.03 to 5000 degrees per second. That is a range of over 160,000. I suspect that will be difficult to achieve without a change-gear mechanism to give you different speed ranges.
Stepper motors are good for very slow speeds - but they move in steps. And it can be difficult to achieve high speeds or to control their torque.
...R
The Motor will be used to turn the ball Joint in housing. I have already sensors to measure Forces and hysterisis.
so here i will connect the motor shaft to top side the ball joint and will let it turn and take the hysterisis results.
Well why do i need to control it, its because i will turn it different Speeds, for example
turn 5 sec at 0,005 rpm
raise Speed for 0,1 rpm for every 5 sec till it get 20 rpm
then raise Speed for 2 rpm for every 2 sec till it get 100 rpm
stop
begin from 50 rpm for 5 sec
raise Speed for 5 rpm for every 5 sec till 850 rpm
stop
Turning so slow is required because this ball joint is used in axles and the Minimum turn angle is about 0,03 degree/sec. (Hydraulic) so i should be able to test this tiny Motion also there is a huge frictions because of the stick slip effect. so i want to examine this effect and draw a stribeck Curve for it.
so by the way if i use a gearmotor i guess i cant have the same Torque for every rpms.
The diffuculty here is also having the same torque around 0,5 Nm for every Speed.
Here is the equation:
P = 2.pi.Md.n
while Md (Torque) is const. i need the rev raise so i should give it more power. I dont know how much its possible to be success with it.
Looking at your diagram I am not sure, from your description whether you want to rock the top screwed end from side to side or whether you want to hold the ball-unit vertical and rotate it within its socket in the sense that one rotates an axle. Ball joints are designed to accommodate both motions.
In any case I reckon you are {a} looking for mechanical advice on a computer programming forum and {b} looking for advice about an extremely technical subject that is unlikely to be familiar to hobby programmers.
To apply constant torque you will almost certainly need a device for measuring the applied torque and code to adjust the motor power in a feedback loop.
...R
You are right, i am searching for a mechanical advice. I thought maybe someone has an idea about it.
The ball joint will rotate inside of the socket.
Thanks for your help anyway!
kaanoz9:
Hello everyone,what i need is a really slow Servo Motor.
It should work at 0,5 Nm Torque continuously and also has to be work between 0,03 Degree/Second to 5000 Degree/Second.
So does anybody have an idea how to find such a motor ?
I dont want to use gearboxes because it will cause to fail my test results.
Then you will need quite a large motor. The torque from a motor scales with the
volume of the motor.
Translating your requirements it seems you need speed control from 0.005rpm to 830rpm at
0.5Nm. Thus the max mechanical power is clearly about 40W (0.5 x (830/60)2pi).
A 0.5Nm motor will likely weigh about 1kg and be rated for 200W or more anyway, so power is
not going to be the limiting factor.
The low speed requirement means either you need an encoder and velocity feedback (ie closed
loop control), or will have to use a stepper motor (open loop control).
For high torque at speed, a stepper is going to be larger, 830rpm is pretty fast for a stepper
so you'll be at the tail end of the torque-speed curve.
Steppers also involve a lot of vibration which may be a problem. Microstepping can control
this and give you the slow velocities too.
Thanks for any help!
Sincerly
I think what you really need is a proper industrial servo motor, these are designed for such tasks,
high power, high torque, high accuracy speed,torque or position control under programatic control.
kaanoz9:
You are right, i am searching for a mechanical advice. I thought maybe someone has an idea about it.The ball joint will rotate inside of the socket.
Thanks for your help anyway!
My advice is to use a hydraulic motor with a high volume, high pressure pump and use an electronic controller to adjust the oil pressure/volume applied to the motor. This gives you both really low speed and really high speed and everything in between.
Paul