Compliant mechanisms

[cox]

I found this interesting, and thought it might be for others on here.

https://www.youtube.com/watch?v=97t7Xj_iBv0

[DeepSOIC]

One of the most fascinating compliant mechanism I ever touched was one in a precision balance.
It's a lever system, probably EDM-machined from a single block of ?bronze?.

WP_20141224_22_06_25_Pro_reduce.jpg (553.25 KiB) Viewed 222 times

balance closeup.jpg (584 KiB) Viewed 222 times

[mlampert]

Came across compliant mechanisms a few weeks ago and am massively fascinated by them. Would you know how this balancer works?

[DeepSOIC]

Would you know how this balancer works?

Of course I do.

Here's a crude animation of the lever movement.

balance-compliant-lever.gif (372.24 KiB) Viewed 189 times

The weight to be weighed is put onto the slowly moving group on the right. There is a voice coil motor on the end of the long lever (on the left side). And an optical position sensor. The motor and the sensor are tied in a feedback loop, so the lever never moves (the motor compensates the force created by weight being measured). ADC samples the current flowing through the motor, and converts it into a displayed value.

[mlampert]

Awesome - thanks a lot!