My Robotic arm is not moving when I give the x and y and z values to form a pose goal, What to do? I get the following errors. [Error] Unable to sample any valid states for goal tree

answered 2018-09-27 11:47:06 -0600

mvkzenith
1 ●1 ●1 ●4

updated 2018-09-27 11:50:16 -0600

When I try to move the Arm using Python code, I get the following output

============ Starting tutorial [ INFO] : Loading robot model 'pi_robot'...

[ INFO] : Loading robot model 'pi_robot'...

[ INFO] : Ready to take commands for planning group base_arm.

============ Reference frame: /base_rotary

============ Robot Groups:

['base_arm', 'claws']

============ Printing robot state

joint_state: header: seq: 0 stamp: secs: 0 nsecs: 0 frame_id: "/base_rotary" name: [base_rotary3, rotary_biceps, biceps_forearm, Forearm_wrist, wrist_rotary_claw, claw_gripper_1, claw_gripper_2, link_claws] position: [-0.9492579224650748, 0.23973554670321753, 0.9810336592943874, 0.20257978661255913, 0.3314634015831165, 0.0, 0.0, 0.0] velocity: [] effort: [] multi_dof_joint_state: header: seq: 0 stamp: secs: 0 nsecs: 0 frame_id: "/base_rotary" joint_names: [] transforms: [] twist: [] wrench: [] attached_collision_objects: [] is_diff: False

============

============ Waiting while RVIZ displays plan3...

And Rviz gives the following Output

[ INFO] : Planner configuration 'base_arm' will use planner 'geometric::RRTConnect'. Additional configuration parameters will be set when the planner is constructed.

[ INFO] : RRTConnect: Starting planning with 1 states already in datastructure

[ERROR] : RRTConnect: Unable to sample any valid states for goal tree

[ INFO] : RRTConnect: Created 1 states (1 start + 0 goal)

[ INFO] : No solution found after 5.004745 seconds

[ INFO] : Unable to solve the planning problem

[ INFO] : Combined planning and execution request received for MoveGroup action. Forwarding to planning and execution pipeline.

[ INFO] : Planning attempt 1 of at most 1

[ INFO] : Planner configuration 'base_arm' will use planner 'geometric::RRTConnect'. Additional configuration parameters will be set when the planner is constructed.

[ INFO] : RRTConnect: Starting planning with 1 states already in datastructure

[ERROR] : RRTConnect: Unable to sample any valid states for goal tree

[ INFO] : RRTConnect: Created 1 states (1 start + 0 goal)

[ INFO] : No solution found after 5.009016 seconds

[ INFO] : Unable to solve the planning problem

[ INFO] : Received event 'stop'

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Comments

These error messages are telling you that the planner can't find a solution to that pose using your robot arm. In a nut shell your arm cannot reach that goal pose.

PeteBlackerThe3rd ( 2018-09-27 12:08:36 -0600 )edit

I can Understand that! I want to know why? What's the solution for this?

mvkzenith ( 2018-09-27 12:49:44 -0600 )edit

Start by trying some different poses. Maybe a little bit closer to the robot.

AndyZe ( 2018-09-27 13:38:34 -0600 )edit

poses are working, But when I give the following, it is not working

pose_goal = geometry_msgs.msg.Pose()
pose_goal.orientation.w = 1
pose_goal.position.x = 0
pose_goal.position.y = 0
pose_goal.position.z = 0
group.set_pose_target(pose_goal)

plan1 = group.plan

mvkzenith ( 2018-09-27 13:58:22 -0600 )edit

(0,0,0) is likely inside the base of the robot --> collision. Again, try a different pose. I think you can do get_planning_frame() to see what your coordinate frame is.

AndyZe ( 2018-09-27 16:43:44 -0600 )edit

============ Reference frame: /base_rotary ============ Robot Groups: ['base_arm', 'claws'] ============ Printing robot state

Tried with different pose! (2,2,2)

mvkzenith ( 2018-09-28 04:14:09 -0600 )edit

[Error] Orientation constraint for link 'claw_motor' is probably incorrect: 0.000000, 0.000000, 0.000000, 0.021194. Assuming identity instead.

WHat about this?

Panda Arm is working when I give a Valid Point, But not My arm. WHy?

I will upload my URDF?

mvkzenith ( 2018-09-28 08:36:03 -0600 )edit

I don't believe those values correspond to a valid Quaternion, that is probably why you get that warning.

gvdhoorn ( 2018-10-01 04:03:40 -0600 )edit

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My Robotic arm is not moving when I give the x and y and z values to form a pose goal, What to do? I get the following errors. [Error] Unable to sample any valid states for goal tree

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My Robotic arm is not moving when I give the x and y and z values to form a pose goal, What to do? I get the following errors. [Error] Unable to sample any valid states for goal tree