Varying vibration strength on same voltage

[Sai teja]

Hello, I am using ERM vibration Motor for haptic feedback application. At different trials, Vibration motor is vibrating with different vibration intensities on same same voltage.

I am unable to figure out the reason. Can some one help me in this aspect?

Thank you.

[Andy Watson]

You are trying to convey mechanical energy (vibration) into a "load", possibly via several intermediate couplings. The load, and all the intermediate couplings have a mechanical impedance. Just as with electrical sources and loads you have to pay attention to matching impedances if you want to convey the optimum amount of energy. As with electrical impedance, mechanical impedance has complex components and is frequency sensitive.

You mention "haptic" feedback - so ultimately your mechanical load will be human skin? Good luck with that The mechanical impedance of skin varies enormously depending location, fat content, age and muscle tone.

[Rerouter]

A motors voltage only tells you the speed it is rotating at, and thus the frequency of vibrations, (The voltage generated by it spinning at a given speed cancels the voltage supplied),

To know intensity, e.g. how much force it is putting in would require constant current driving, as the better the bit of skin its vibrating against is at absorbing those vibrations, the more current the motor will pull to try and maintain that speed.