[ros-users] unable to get valid path when calling /ompl_planning/plan_kinematic_path

Mon Feb 14 12:41:23 UTC 2011

Dear community,

I feel a little desperate since I don't know what I'm doing wrong here:
 From within our grasp_planner, I want to call the 
"/plan_kinematic_path" service from the ompl package.

Here is how I set it all up:

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  ros::service::waitForService("/ompl_planning/plan_kinematic_path");

   ros::ServiceClient client = 
n.serviceClient<motion_planning_msgs::GetMotionPlan>("/ompl_planning/plan_kinematic_path");

   motion_planning_msgs::GetMotionPlan::Request req;
   motion_planning_msgs::GetMotionPlan::Response res;

   std::vector<std::string> names(7);
   names[0] = "arm_1_joint";
   names[1] = "arm_2_joint";
   names[2] = "arm_3_joint";
   names[3] = "arm_4_joint";
   names[4] = "arm_5_joint";
   names[5] = "arm_6_joint";
   names[6] = "arm_7_joint";

req.motion_plan_request.goal_constraints.joint_constraints.resize(names.size());
   for (unsigned int i = 0 ; i < names.size(); ++i)
   {

req.motion_plan_request.goal_constraints.joint_constraints[i].joint_name 
= names[i];

req.motion_plan_request.goal_constraints.joint_constraints[i].position = 
0.0;

req.motion_plan_request.goal_constraints.joint_constraints[i].tolerance_below 
= 0.1;

req.motion_plan_request.goal_constraints.joint_constraints[i].tolerance_above 
= 0.1;
   }

   //req.motion_plan_request.planner_id="";
   req.motion_plan_request.group_name="arm";
   req.motion_plan_request.num_planning_attempts=1;
   //req.motion_plan_request.allowed_planning_time=ros::Duration(50.0);

   ROS_INFO("calling service...");
   if (client.call(req, res))
   {
     ROS_INFO("Result: %d", res.error_code.val);
   }
   else
   {
     ROS_ERROR("Failed to call service plan_kinematic_path");
     return 1;
   }
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

I.e. I just want a plan that brings the arm back into its home position 
at (0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0).

The output from the planner is the following (with Debub output):

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
[ INFO] [1297684313.476421959, 56.604000000]: Received request for planning
[ INFO] [1297684313.476537217, 56.604000000]: Selected motion planner: 
'kinematic::LBKPIECE[LBKPIECEkConfig2cob]', with priority 11
[DEBUG] [1297684313.476605128, 56.604000000]: No workspace bounding 
volume was set
[ INFO] [1297684313.479051337, 56.604000000]: ompl planning for group arm
[DEBUG] [1297684313.479230006, 56.604000000]: Start states before 
normalization 0 val 0.537644
[DEBUG] [1297684313.479279888, 56.604000000]: Start states before 
normalization 1 val -1.20871
[DEBUG] [1297684313.479314884, 56.604000000]: Start states before 
normalization 2 val 0.204787
[DEBUG] [1297684313.479346079, 56.604000000]: Start states before 
normalization 3 val 0.943959
[DEBUG] [1297684313.479377832, 56.604000000]: Start states before 
normalization 4 val -0.0503284
[DEBUG] [1297684313.479408952, 56.604000000]: Start states before 
normalization 5 val 0.00951776
[DEBUG] [1297684313.479439600, 56.604000000]: Start states before 
normalization 6 val -0.00680026
[DEBUG] [1297684313.479473040, 56.604000000]: Start states after 
normalization 0 val 0.537644
[DEBUG] [1297684313.479504849, 56.604000000]: Start states after 
normalization 1 val -1.20871
[DEBUG] [1297684313.479534850, 56.604000000]: Start states after 
normalization 2 val 0.204787
[DEBUG] [1297684313.479564637, 56.604000000]: Start states after 
normalization 3 val 0.943959
[DEBUG] [1297684313.479594670, 56.604000000]: Start states after 
normalization 4 val -0.0503284
[DEBUG] [1297684313.479625155, 56.604000000]: Start states after 
normalization 5 val 0.00951776
[DEBUG] [1297684313.479655881, 56.604000000]: Start states after 
normalization 6 val -0.00680026
[DEBUG] [1297684313.480120098, 56.604000000]: Kinematic state space 
settings:
   - dimension = 7
   - start states:
0.537644 -1.20871 0.204787 0.943959 -0.0503284 0.00951776 -0.00680026
Goal state, threshold = 1e-12, memory address = 0x7fb9b40adb00, state = 
0 0 0 0 0 0 0
Joint constraints:
[-0.1, 0.1] [-0.1, 0.1] [-0.1, 0.1] [-0.1, 0.1] [-0.1, 0.1] [-0.1, 0.1] 
[-0.1, 0.1]
   - bounding box:
[-2.957, 2.957](0.05914) [-2.0843, 2.0843](0.041686) [-2.957, 
2.957](0.05914) [-2.0843, 2.0843](0.041686) [-2.957, 2.957](0.05914) 
[-2.0844, 2.0844](0.0416879) [-2.957, 2.957](0.05914)
Path constraints:
0 kinematic constraints

[DEBUG] [1297684313.480187558, 56.604000000]: Goal threshold is 1e-12
[DEBUG] [1297684313.480328546, 56.604000000]: Collision but allowed 
touch between sdh_thumb_2_link and sdh_thumb_3_link
[DEBUG] [1297684313.480372852, 56.604000000]: Collision but allowed 
touch between sdh_finger_23_link and sdh_thumb_3_link
[DEBUG] [1297684313.480404417, 56.604000000]: Collision but allowed 
touch between sdh_finger_12_link and sdh_finger_13_link
[DEBUG] [1297684313.480434052, 56.604000000]: Collision but allowed 
touch between sdh_palm_link and sdh_thumb_2_link
...
//some more allowed collisions
//not a single collision is not allowed!!!
...
[DEBUG] [1297684313.507005162, 56.607000000]: Collision but allowed 
touch between arm_1_link and arm_2_link
[DEBUG] [1297684313.507287845, 56.607000000]: Collision but allowed 
touch between arm_0_link and arm_1_link
[DEBUG] [1297684313.507593130, 56.607000000]: Collision but allowed 
touch between torso_tray_link and base_link
[DEBUG] [1297684313.507913948, 56.607000000]: Collision but allowed 
touch between head_cover_link and torso_upper_neck_tilt_link
[DEBUG] [1297684313.508219712, 56.607000000]: Collision but allowed 
touch between torso_lower_neck_tilt_link and torso_upper_neck_tilt_link
Info:    LBKPIECE1: Starting with 2 states
Info:    LBKPIECE1: Created 2 (1 start + 1 goal) states in 2 cells (1 
start + 1 goal)
[DEBUG] [1297684313.508655728, 56.607000000]: [Failure] Motion planner 
spent 0.0222179 seconds
[DEBUG] [1297684313.508999801, 56.607000000]: Total planning time: 
0.0222179; Average planning time: 0.0222179
[ INFO] [1297684313.509273713, 56.607000000]: Ompl says ok
[DEBUG] [1297684313.509664645, 56.607000000]: New motion priority for  
'kinematic::LBKPIECE[LBKPIECEkConfig2cob]' is 10
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

What irritates me is that "Ompl says ok".......because it's not...=)
Still the solution trajectory is empty and the error_code.val is 0.

I can use the "/plan_kinematic_path" service successfully when it is 
called from within the move_arm_action!
But since I don't want the robot to move at this point, I just want to 
call the planner and execute the trajectory later.
I also checked how the move_arm_action_server sets up the 
/plan_kinematic_path request and I couldn't find a difference.

Is there anything that I missed while setting the request?
How else can I get the solution trajectory to a joint_goal without 
executing the movement?

Thanks for your help!

Best,
Felix