some issues about FT300

class 2021-04-22

When I used FT300,I met some issues about the datas.Before use it, I have done the calibration and zero the data.But when I control a joint vertically downwards, the force data obtained has components in other directions.What could be the reason that caused this result.

class 2021-04-22

bcastets 2021-04-22

@class
From what I understand, you:

Made the zero of the sensor with the sensor installed like shown on the picture
Move the robot vertical downward
Identified an offset of -9.7N on Z axis

It is possible internal deformation of the force sensor remain after some motion and cause an offset. This is usually an offset of about 3N.

What is the weight of the object ?
What is the acceleration of the robot when you do the vertical motion ?

class 2021-04-23

Hi,
The weight is 916g and the robot is Stationary state.Before I done calibration and zero the sensor, I didn't install the object. When I finish calibration and zero the sensor, I install the object and the robot is stationary state.The sensor has a component of force in a direction where no force should appear.

bcastets 2021-04-23

@class
The zero of the sensor should be done with the object on the robot. Each time you mount something on the sensor, this will induce constrains on the sensor and offset readings.
With such offset weight, I would also recommend to work with torque rather than force. Offset weight can induce parasitic force.