actuator torque measurment setup

[vish.solanki]

i am developing a torque measurement setup...for measuring actuator rotary torque

(range of actuatotar torque :0-300 lb-in, the actuator shaft moves only 0-45 degrees) 

The actuator shaft, is coupled to the torque sensor,:

 what kind of load will be suitable to apply torque on the shaft?----- brake or motor etc

Can anybody throw light on this torque measurement setup, or explain their understanding

Regards

vish

[vish.solanki]

here is the image attached

Can someone clarify/explain the operation , of this setup to measure torque...with load as motor

regards

vishal

[Jochen]

Vish,

the type of load depends on your task. If you need to characterize your actuator by keeping the torque stable over the whole travel range, you will need to use a motor in closed loop mode (torque control) as a  load. The same is true, if you need to measure any dynamic characteristics.

If you just want to know the maximum torque your actuator can provide at any angle and if it is ok for you to do this in static mode (motor doesn't move), you also could use a brake to stop the motor at certain positions and measure the static torque there.

In any case you will probably need to correlate position and torque, so you should use a position feedback device (e. g. quadrature encoder) and run a synchronized torque/position measurement. A cost effective way to do this is using an M-Series device from NI.

If you need more detailed information, please explain a bit more in detail what you are trying to accomplish.

Thanks and kind regards,

Jochen Klier

National Instruments

[vish.solanki]

Hello Jochen,

Thanks for reply...suggestion

my actuatoris a device( in a closed case with motor,pcb circuit, ) i have exeternal interface as electrical connector and output shaft...thats it

My actuator is rotary type torque, shaft diameter is about 13mm, it is a valve actuator, it will open and close (ie. rotate 45 degrees)

I want to measure the torque (its testing application), on-off operating time of actuator, and to apply a load torque to the actuator shaft,

(maximum 0-250 in-lb)

I have to also precise give load torque to the shaft, programatically, so I am thinking of which kindly of load to apply torque (a stepper motor, a brake etc)...if stepper motor (i will need a drive to apply specific torque).....or other kind of load??

Can you also explain me if i use stepper motor, how will be the operation of setup be......to apply torque to my actuator

i put my understanding of setup here below :

actuator--------------------torque sensor-------------------loading component( stepper motor, brake etc)

                   coupled                                      coupled

if i move actuator shaft clockwise, i have exert a torque by load(stepper motor anticlockwise)....and vice versa...

can you throw light on my understanding ...and the technique for torque measurement

I would also like to know the torque sensors avaibiale with NI, i have few from honeywell, himmelstien, others..

I will be using LabVIEW 8.5 for data acusition from my torque sensor...and controlling the load to give precise torque on the actuator

Waiting for Reply

Thanks & regards

Vishal

[Jochen]

Vishal,

thank you for the additional information.

You suggest to use a stepper motor as a load, but this is not a good fit for your application, as there is no good way to use a stepper motor for torque control. If you command a stepper motor to move, it will apply the necessary torque to perform the move. If the torque is too high, a step failure will occurr and the motor stop. Stepper motors are designed for precise positioning, but not for torque control.

A much better choice is a DC motor in closed loop mode (sevo). For precise torque control you could use an NI 7350 board. This board provides 16 bit analog inputs that can be used as feedback inputs, so you can use this board for closed loop torque control, when connecting the output signal of your torque sensor (+/- 10 V) to an analog input of the board.

The same board can be used to control the valve's position and trajectory if an appropriate feedback signal (quadrature encoder or analog signal) is available.

NI doesn't provide torque sensors, but if you want to use a 7350 as the control device, you will have to make sure, that the sensor's output signal is within a valid range of the 7350 (+/- 10 V or +/- 5 V).

For a more in-depth system consulting I recommend to contact your local NI branch.

Thanks and kind regards,

Jochen

[Valve123]

Hello,

I am trying to design a system to test/characterize the torque on electronic actuators (used on valves). The set up I have i mind is connecting the electronic/test actuator to a load cell which would be connected to a pneumatic  actuactor via a shaft. As the shaft rotates the load cell detects the torque which is recorded. I have a rough design in mind but I cannot figure out how to begin testing it on LABVIEW. Some help to start it on Labview will be appreciated. Thanks

[abhishek.d]

Hi Vishal I have similar kind of requirement i need some guidance for it.

In mY application i have a shaft which is rotated by applying torque signal to the actuator using a Controller
(which is of MTS manufacture)

So i need to send an output signal of 0 to 10v which should corresponds to 0 to 5000 Lb-inch in my controller so that my controller sends the signal to the actuator and based on that acquire signal and i monitor the angular displacement

Please give me some to start up with, i basically have experience in anlog in and out programs

Please let me know if u need any other details