Hello, I have a problem,
I am writing an application for deburring metal.
I have connected a tool with a deburring chamber to the robot. Now when the robot has to deburr the part sideways, it starts bouncing.
How can I adjust the force in real time so that the robot stops bouncing? or what can I do to stabilise the force?
Hi sakhr.
Which robot are you using?
For Force applications I highly recommend using a e-series, as it has an inbuilt force-torque sensor.
Otherwise you might need buy an external force torque sensor to get an accurate measurement.
The CB- series uses the power consumption of each joint to approximate the force this might be good enough for your application but it might also be the very thing that is given you problems.
Please also check if your COG and Payload are calibrated properly because if not they would also result in something similar to what you see.
Best Regards CG1
I use UR-10 e,
the programme is simple, I wrote on Polyscop so no script
Force on tool x-axis and then loop for 5 times with movement linear
I used 10 N and speed limits with 300ms
Hi Again.
With a large tool like that your TCP also needs to be calibrated in order for the robot to compensate for the torque created, correctly.
If this is does not help, consider switching to using script “force_mode(task_frame, selection_vector, wrench, type,
limits)” as this will give you more fine control over the force mode as you can here adjust the maximum allowed deviation in non-compliant axes, the max deviation in angle might be nice to control in your aplication. Please see script manual for futher details.
and the damping can also be controlled through “force_mode_set_damping(damping)”
and the gain through “force_mode_set_gain_scaling(scaling)”.
this fine control might give you a better result.
Hello ,
Thanks for your help agin ,
just one question, can I use force_mode() in the Polyscope or do I have to write the whole programme as a script ?t
Hi again.
polyscope has a script node, that allows you combine both script calls and polyscope programming, it can be found in the advanced drop down menu…
for convenience sake you can put a physical keyboard into the usb of the teach pendant this makes it alot easier to write scipt functions.
Best Regards.
Hi again.
By the way the promised force precision of the ur10e is ±10N, as far as I can remember (please double check it yourself)
so you are playing right on the boarder of what might be possible.
if you application allows it I would therefore recommend increasing the force.
if you need your force to be this “low” an external force torque sensor with better precision might still be necessary and is easily integrated through script code
enable_external_ft_sensor(enable, sensor_mass=0.0,
sensor_measuring_offset=[0.0, 0.0, 0.0], sensor_cog=[0.0, 0.0,
0.0]))
PS: also forgot to mention the
zero_ftsensor()
script function which is absolutely essential to your application.
Hi again,
the Precision by UR10e is +5/-5 N but thx I will take it into consideration.
but what do you mean by zero_ftsenoer() should I use it?
Hi sakhr
Thanks for reminding me of the actual precision and sorry for the confusion.
Yeah the zero_ftsensor() script function basically zeros the values from force torque sensor in the robot.
this is necessary to call before force_mode activates if you want the sensor to disregards the weight of the tool so you get a more clean force measurement.
Best Regards
The problem is that you have 0 in all your limits (the last array) for you non-compliant axes (the ones that has 0 in the selction vector.).
try increasing them all to an acceptable number and try again.
it does not work, I can not untersatnd why? because on URsim its working