Potential Hands/Grippers servo problem?

Hitec robotics including ROBONOVA humanoid, HSR-8498HB servos, MR C-3024 Controllers and RoboBasic
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Potential Hands/Grippers servo problem?

Post by Kelpy » Sat Sep 04, 2010 8:37 pm

Post by Kelpy
Sat Sep 04, 2010 8:37 pm

I'm thinking of making some grippers or hands for my Robonova, but have a question hopefully someone can answer.
What stops a servo from closing too far onto an object and crushing/damaging it?
Is it easy to write a routine that will tell the processor to stop moving the servo when an obstuction is felt?
Presumably if some sort of code is not included, the servos will soon burn out.
I have to say I am a complete novice, so if anyone has written something like this, and would be willing to share, I'd be very grateful.
I'm thinking of making some grippers or hands for my Robonova, but have a question hopefully someone can answer.
What stops a servo from closing too far onto an object and crushing/damaging it?
Is it easy to write a routine that will tell the processor to stop moving the servo when an obstuction is felt?
Presumably if some sort of code is not included, the servos will soon burn out.
I have to say I am a complete novice, so if anyone has written something like this, and would be willing to share, I'd be very grateful.
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Post by limor » Sun Sep 05, 2010 12:41 am

Post by limor
Sun Sep 05, 2010 12:41 am

There are several approaches to this problem. here are a couple that were discussed here in the past.

1) force sensor (see wiki) - put it in the gripper and continuously sense looking for a peak then stopping the movements.

2) position sensing - if you gradually move the servo towards a position (ie: set the target position to previous angle + 1, read servo position continuously till it reaches that position etc.) and read the position feedback then you can tell when a step was not executed properly and you know there's external torque thats preventing from the motion
There are several approaches to this problem. here are a couple that were discussed here in the past.

1) force sensor (see wiki) - put it in the gripper and continuously sense looking for a peak then stopping the movements.

2) position sensing - if you gradually move the servo towards a position (ie: set the target position to previous angle + 1, read servo position continuously till it reaches that position etc.) and read the position feedback then you can tell when a step was not executed properly and you know there's external torque thats preventing from the motion
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Post by Kelpy » Mon Sep 06, 2010 7:00 pm

Post by Kelpy
Mon Sep 06, 2010 7:00 pm

Many thanks for your reply, Limor.

I think the force sensor sounds the best way for me to go. I suspect the coding for it will be simpler for me than trying to get feedback from servos and making decisions on that. Especially as I am struggling with the simplest of coding as it is :oops:
Many thanks for your reply, Limor.

I think the force sensor sounds the best way for me to go. I suspect the coding for it will be simpler for me than trying to get feedback from servos and making decisions on that. Especially as I am struggling with the simplest of coding as it is :oops:
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