# Gripper mechanism problem **URL:** \ **Category:** RobotStudio\ **Created:** [December 2, 2016, 11:04am UTC](https://tech-community.robotics.abb.com/t/gripper-mechanism-problem/7468 "2016-12-02T11:04:17Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![Marmur911](https://avatars.discourse-cdn.com/v4/letter/m/258eb7/32.png) [@Marmur911](https://tech-community.robotics.abb.com/u/Marmur911)\ **Post date:** [December 2, 2016, 11:04am UTC](https://tech-community.robotics.abb.com/t/gripper-mechanism-problem/7468/1 "2016-12-02T11:04:17Z")
Hello everyone, I have a problem with creating mechanism in robotstudio. My mechanism is a gripper designed for my application, I can’t compose it in robotstudio, program displays message that it cannot compile mechanism.My gripper looks like this:(linear move of pink element is converted to rotation of gripper jaws thanks to yellow connectors) Everything works until I create rotational joint between green housing and jaw, when I try to compile mechanism it says it is imposible. Am I doing something wrong or it is just application error? my robotstudio version is 6.03 please help. ---
**Author:** ![Marmur911](https://avatars.discourse-cdn.com/v4/letter/m/258eb7/32.png) [@Marmur911](https://tech-community.robotics.abb.com/u/Marmur911)\ **Post date:** [December 2, 2016, 11:55am UTC](https://tech-community.robotics.abb.com/t/gripper-mechanism-problem/7468/2 "2016-12-02T11:55:31Z")
This is how it looks like in RobotStudio [http://https//drive.google.com/open?id=0Byyvz1G2Wll4RmJuaTRUNjlYcW8](http://https://drive.google.com/open?id=0Byyvz1G2Wll4RmJuaTRUNjlYcW8) Can someone please tell me what am I doing wrong? ---
**Author:** ![Keke](https://dub1.discourse-cdn.com/flex005/user_avatar/tech-community.robotics.abb.com/keke/32/193_2.png) [@Keke](https://tech-community.robotics.abb.com/u/Keke)\ **Post date:** [December 22, 2016, 12:30pm UTC](https://tech-community.robotics.abb.com/t/gripper-mechanism-problem/7468/3 "2016-12-22T12:30:39Z")
I think this sort of closed loop kinematics require putting dependencies on other joints. RS doesn’t do this automatically like some CAD (e.g.SolidWorks) software are able to do. This means you must solve some nasty equations on the links. Attahed there is a zip which contains a RS library of a similar example. Just import it and click “Modify Mechanism” on the right mouse button context menu to see the joints and their dependencies. There’s also a picture of the depency equations attached. I used RS6.04.01 to make the library, hopefully it works on older versions as well. BR, Keijo [Gripper.zip](https://tech-community.robotics.abb.com/uploads/short-url/a1qkzcnRcZU379EptvFiZJcKMXr.zip) (93.5 KB) ---
**Author:** ![Marmur911](https://avatars.discourse-cdn.com/v4/letter/m/258eb7/32.png) [@Marmur911](https://tech-community.robotics.abb.com/u/Marmur911)\ **Post date:** [December 28, 2016, 3:44pm UTC](https://tech-community.robotics.abb.com/t/gripper-mechanism-problem/7468/4 "2016-12-28T15:44:21Z")
Keke, Your gripper works perfectly! But I think it is too complicated for me to build those eqations for visual effects only. I cannot edit mechanism, RS says it has unknown error. ![image.jpg](https://europe1.discourse-cdn.com/flex005/uploads/robotics1/original/2X/0/0f611c36d24cc5adec5976350e1492f64f2701ca.jpeg) Looks like I need to update my software. By the way I don’t know how to access dependency of joints. How to acces that? ![image.jpg](https://europe1.discourse-cdn.com/flex005/uploads/robotics1/original/2X/0/0f611c36d24cc5adec5976350e1492f64f2701ca.jpeg) ---
**Author:** ![Keke](https://dub1.discourse-cdn.com/flex005/user_avatar/tech-community.robotics.abb.com/keke/32/193_2.png) [@Keke](https://tech-community.robotics.abb.com/u/Keke)\ **Post date:** [January 19, 2017, 8:59am UTC](https://tech-community.robotics.abb.com/t/gripper-mechanism-problem/7468/5 "2017-01-19T08:59:29Z")
You can add depencies when compiling a device. Like in my example I have put dependency on j31, where I compute its value using a formula. In the formula you can see the leading joint J1. If the depndency is simply a scaled value of another joint (e.g 10\*J1), you can use the “Use LeadJoint and factor” option. But you are correct, dependendies are mostly used for visual purposes so they don’t matter that much. ![image.png](https://europe1.discourse-cdn.com/flex005/uploads/robotics1/original/1X/6c1db68406d496423d5596b1e16394182c9ec87f.png) ![image.png](https://europe1.discourse-cdn.com/flex005/uploads/robotics1/original/2X/a/a3159dda909024fab6b3ebaadaaf150647b92e1d.png) -K ![image.png](https://europe1.discourse-cdn.com/flex005/uploads/robotics1/original/1X/6c1db68406d496423d5596b1e16394182c9ec87f.png) ![image.png](https://europe1.discourse-cdn.com/flex005/uploads/robotics1/original/2X/a/a3159dda909024fab6b3ebaadaaf150647b92e1d.png) ---
**Author:** ![Christopher\_Pp](https://avatars.discourse-cdn.com/v4/letter/c/e47c2d/32.png) [@Christopher\_Pp](https://tech-community.robotics.abb.com/u/Christopher_Pp)\ **Post date:** [June 25, 2018, 8:31pm UTC](https://tech-community.robotics.abb.com/t/gripper-mechanism-problem/7468/6 "2018-06-25T20:31:06Z")
Hello Keke, I left you a private message. I hope you can review … Thank you!