[pr2eus] add gain key in :stop-grasp

[knorth55]

We need to change gain also for :stop-grasp.
This is because we introduce Gecko tape on PR2 finger tip.

[pazeshun]

What happens when gain is default?

[YutoUchimi]

PR2 tries to open his gripper, but cannot achieve for about 3~20 seconds (It seems that the latency depends on the time since last :start-grasp and probably on grasping gain...?).
I tested this PR with real robot and it works fine.

[k-okada]

Is this because we have changed gripper ? Why we do not need this until now..... 2019年11月6日(水) 10:39 Yuto Uchimi <notifications@github.com>:

PR2 tries to open his gripper, but cannot achieve for about 3~20 seconds (It seems that the latency depends on the time since last :start-grasp and probably on grasping gain...?). I tested this PR with real robot and it works fine. — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#415?email_source=notifications&email_token=AADYNXHIDZSS3DYAQRW3PYTQSIN25A5CNFSM4JJGUELKYY3PNVWWK3TUL52HS4DFVREXG43VMVBW63LNMVXHJKTDN5WW2ZLOORPWSZGOEDE6HBQ#issuecomment-550101894>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AADYNXCNFWWCYFAB3P7BMYDQSIN25ANCNFSM4JJGUELA> .

-- -- ◉ Kei Okada

[YutoUchimi]

Yes, we introduced new fingertips with Gecko tape into PR1040 yesterday, and this is the first time to use it.

[knorth55]

Gecko tape is strongly attached if PR2 closes the gripper with some effort.
That's why we need to set more effort to open the gripper.

[knorth55]

It is like a lottery to pass travis test.
I strongly want to merge #417 and make test work properly.

[knorth55]

@k-okada Travis test passed. Could you merge this PR?

[k-okada]

@knorth55 what is 0.03 means and why you multiply by 2000 ?

[knorth55]

@k-okada
I just follow line in :start-grasp. I have no idea why :gain is multiplied by 2000.
https://github.com/jsk-ros-pkg/jsk_pr2eus/blob/master/pr2eus/pr2-interface.l#L266-L267

I digged up commit history and found that this weird 2000 is added in 2010.
dfef9d8

[knorth55]

@k-okada according to PR2 manual, max effort of PR2 gripper joint is 1000N. so probably, (* gain 1000) might be reasonable now.
was the max effort 2000 in 2010 and set lower limit now?