Force control

Force control is possible using integrated drive with some limitation due to the resolution of the current loop. Firmware to be used for a correct force control is starting from version 5A51.

Example of two position application with force control

In order to have one position where a force control take place we need two specify three motion task in the motion controller table, like in the screenshot below.
In this example, position 0 is 10 mn and the position 1 is 52mm where the force control will applied with a force of 8 N with a duration of 1sec.

force_motion.jpg

The sign of the force specified in the table must correspond to the direction of the slider, as in this photo.

nli120q_force_direction.jpg

We suggest to reduce to a minimum the wait time in the task force to avoid overshot in the postion when the force control switch to position control.
In order to have a good response, we suggest to increase Ki integral in current loop.

current_loop.jpg

Force control performance

Here below the force measurement variation with the motion table values measured by external load cell.

Load cell: FC2231 (https://www.digikey.at/en/products/detail/te-connectivity-measurement-specialties/FC2231-0000-0010-L/809394 )
Acquistition system National Instruments NI USB-6210 (https://www.ni.com/de-at/shop/model/usb-6210.html)

force_acq.jpg

Force repeatability

force_variation.jpg

Force repeatability is 1,486 +/- 0.035 mV. Considering the force coefficient of 1,63 V/N we have a force repeatability of +/- 0,120 N.

Video Demostration