search

svenschneider / youbot-manipulation

38 stars 41 forks source link

gripper isn't working under Indigo #9

Open ferherranz opened 9 years ago

ferherranz commented 9 years ago

Hello,

I'm using youbot_manipulation under indigo. I launch move_group.launch file in combination with moveit_commander. When I execute: use arm_1_gripper go open

I get the following error: [ERROR] [1437659114.273972520]: Unable to identify any set of controllers that can actuate the specified joints: [ gripper_finger_joint_l gripper_finger_joint_r ] [ERROR] [1437659114.274016429]: Known controllers and their joints: controller 'arm_1/arm_controller' controls joints: arm_joint_1 arm_joint_2 arm_joint_3 arm_joint_4 arm_joint_5

[ERROR] [1437659114.274061944]: Apparently trajectory initialization failed

Any idea? Thank you in advance!

svenschneider commented 9 years ago

Hello Fernando,

unfortunately, this is the "expected" behaviour (also under ROS Hydro). Let me explain the issue: MoveIt! can "plan" trajectories for the gripper (not that there is that much to plan for open/close ;) ). The problem is that the simple MoveIt! controller managers [1] expect either a ROS control_msgs/FollowJointTrajectory [2] action interface or a control_msgs/GripperCommand [3] action interface. However, neither of these is offered by the youbot_driver_ros_interface [4].

There are several ways to solve this issue:

  1. Write a custom controller manager (see e.g. [5] for an overview of the current architecture).
  2. Extend the youbot_driver_ros_interface to include the required interface.
  3. Write an adapter node that translates FollowJointTrajectory or GripperCommand actions to the gripper's position interface [6].

In any case, you have to register the controller in the controllers.yaml configuration file [7].

Best regards Sven

[1] https://github.com/ros-planning/moveit_plugins [2] http://docs.ros.org/indigo/api/control_msgs/html/action/FollowJointTrajectory.html [3] http://docs.ros.org/indigo/api/control_msgs/html/action/GripperCommand.html [4] https://github.com/youbot/youbot_driver_ros_interface/blob/hydro-devel/src/YouBotOODLWrapper.cpp [5] http://moveit.ros.org/wiki/Executing_Trajectories_with_MoveIt! [6] https://github.com/youbot/youbot_driver_ros_interface/blob/hydro-devel/src/YouBotOODLWrapper.cpp#L207 [7] https://github.com/svenschneider/youbot-manipulation/blob/indigo/youbot_moveit/config/controllers.yaml

ferherranz commented 9 years ago

thank you for you help! I'm just starting with moveit and youbot. I'll have a a look at the links!

Best Regards

Fernando

frederikhegger commented 8 years ago

Dear @ferherranz, does it work for you now?