UR3 stops motion after call the gripper service

[MzXuan]

Hello, I'm now using this driver with UR3 and RG2. It works well if I only call the rg2_gripper/control_width service and the gripper can open to the target width.

However, my robot will suddenly stop after I call the gripper service, without showing any warning. It just stops and cannot move again, only if I restart the ur_modern_driver.

Anyone has any idea please help me.

Thanks!

[fruitspunchsamurai]

Hello MzXuan, Does your gripper detect function work correctly?

[MzXuan]

Hello Brian,

I think that function can return the width in mm. But sorry I can not remember if there is an offset because I haven't used it for a long time.

2018-04-17 18:01 GMT+08:00 Brian notifications@github.com:

Hello MzXuan, Does your gripper detect function work correctly?

— You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub https://github.com/sharathrjtr/ur10_rg2_ros/issues/2#issuecomment-381930909, or mute the thread https://github.com/notifications/unsubscribe-auth/AM0sbtL4-Okw82CA8iZWbdkKXKgW_BxQks5tpb2PgaJpZM4R7F3K .

[sharathrjtr]

Hi MzXuan,

Could you please provide the output of ur_modern_driver after the service rg2_gripper/control_width has been called.

[haniehes]

Thanks for your package. My problem is similar. I am using RG2 connected to UR5. It works well if I only call the rg2_gripper/control_width service and the gripper can open to the target width but the problem is voltage drop. when my target is 100mm, the gripper opens but suddenly the output voltage drops to 0. So, if I call another target_width, nothing happens. Also, I see many fluctuations in output voltage during grasping. Is there anyway to fix the voltage after process?

[sharathrjtr]

If the voltage drops to 0 that means it is trying to draw more current. I want to know whether this occur when the gripper is holding an object or it occurs even without holding an object? What is weight of the object? My guess is that there is voltage fluctuation because we are not specifying the payload for the gripper in the code, while the force has been set to 40N (In all my operations the objects were having weight less than 200g so may be because of that I didn't observe such behavior). Could you please let me know whether you observe similar behavior when performed using the teach pendent. Thanks.

[haniehes]

It occurs with or without holding an object. I have tried to grasp a lego block and I saw the disconnection again. Today, I found that rarely it works well and the disconnection doesn't occur(without any changes in the program). Also, I checked Gripper by teach-pendant and I didn't have any problem. However, it is worth mentioning that during this 7 month that I have been using rg2 gripper, I have encountered some voltage drop but not so much.

[sharathrjtr]

Which manipulator are you using UR3, UR5 or UR10? I'll check if there is a dependency on this.

[haniehes]

Ur5 with software version: 3.3.4.

[parthvasoya]

Hi Sharathrjtr,

Thank you for sharing your work. I am very new with ROS and I am trying to control UR3 with rg2 gripper. I am facing a problem calling a service-it says: "ERROR: Service [/rg2_gripper/control_width] is not available." can you guide me to what could be the possible reasons??