I2t parameter configuration in TechnosoftIpos drivers

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I2t parameter configuration in TechnosoftIpos drivers #6

Closed PeterBowman closed 7 years ago

PeterBowman commented 7 years ago

The screenshots below illustrate how are TechnosoftIpos drivers configured in ASIBOT at this time:

driver_setup

driver_info

I'll focus on the I2t Over current checkboxes and text inputs inside the Protections group on both windows. The latter is accessible from the Drive Info button in the upper center of the first screenshot.

Which one of these values is actually taken into consideration by the driver? As Drive Info doesn't let us modify I2t, could we suppose that these values are pulled from the firmware?
How is I2t calculated for TEO?
Regarding TEO, does this value depend on the joint the driver is associated to? (i.e. shoulders and elbows should pick higher values than wrists)
Did you configure I2t through EasySetUp/EasyMotionStudio or via CAN?

CC @roboticslab-uc3m/teo. @edwinDOS please expand in case I missed something.

jgvictores commented 7 years ago

On my behalf, I can only say we do not touch this via CAN. It is set via EasySetUp/EasyMotionStudio.

@smcdiaz @jmgarciah Any help here on the I2t doubts for ASIBOT above, please?

jmgarciah commented 7 years ago

The driver i2t should not be modified. In our case, we calculate the robot TEO i2t. In fact, we calculate the i2t of each of the joints depending on the type of electric motor used.

In the next web link, in chapter 9, it is explained how to calculate several related parameters.

Finally, all the protections of the drivers and of the joints are programmed through EasySetUp

@PeterBowman @jgvictores @smcdiaz

PeterBowman commented 7 years ago

There is not much we can do ATM. Our main constraint are the drivers themselves since we hit the firmware protections (5A for 10 seconds) sooner than the motor ones. In short, whenever ASIBOT starts from a fully horizontal position, it blocks right away due to the firmware I2t and resumes after 30 seconds. While this happens, the reference position is constantly changing, thus the robot arm usually travels to the target at a considerable speed (almost instantaneously) once the protection has cooled down. If we didn't manage to exit the dangerous horizontal zone, we hit the I2t again and so on. On the contrary, the motor's I2t holds for several minutes before reaching a critical value; in this case, motor position is not preserved and the arm drops.

Note how the process described above is different from TEO: the most critical protection is the motor's I2t, hence the need of performing complex analysis and calculations. As said before, there is not much we can do in the case of ASIBOT apart from avoiding current-demanding paths. We'll want to implement a means of monitoring the I2t, but this task should be tracked at yarp-devices.

jgvictores commented 5 years ago

In the next web link, in chapter 9, it is explained how to calculate several related parameters.

The link is broken, but seems interesting. I believe it is https://www.scribd.com/document/336858216/maxon-Formelsammlung-e-pdf

@PeterBowman Any idea on a best practice to perma-link this?

PeterBowman commented 5 years ago

@jgvictores sure: 336858216-maxon-Formelsammlung-e-pdf.pdf.

jgvictores commented 5 years ago

@jgvictores sure: 336858216-maxon-Formelsammlung-e-pdf.pdf.

@PeterBowman Cool, thanks!