error code -21 while calling the ik request.

[Karthikeyan Yuvraj]

Hello,

I was working on this tutorial http://moveit.ros.org/wiki/Kinematics/ROS_API. Bu the robot does not move for any position given. Here is my code:

#include <ros/ros.h>

// MoveIt!

#include <moveit/robot_model_loader/robot_model_loader.h>

#include <moveit/robot_model/robot_model.h>

#include <moveit/robot_state/robot_state.h>

#include <moveit/robot_state/joint_state_group.h>

// Robot state publishing

#include <moveit/robot_state/conversions.h>

#include <moveit_msgs/DisplayRobotState.h>

// Kinematics

#include <moveit_msgs/GetPositionIK.h>

  

int main(int argc, char **argv)

{

  ros::init (argc, argv, "right_arm_kinematics");

  ros::AsyncSpinner spinner(1);

  spinner.start();

  

  ros::NodeHandle node_handle;  

  // Start a service client

  ros::ServiceClient service_client = node_handle.serviceClient<moveit_msgs::GetPositionIK> ("compute_ik");

  ros::Publisher robot_state_publisher = node_handle.advertise<moveit_msgs::DisplayRobotState>( "tutorial_robot_state", 1 );

robot_model_loader::RobotModelLoader robot_model_loader("robot_description"); 

  robot_model::RobotModelPtr kinematic_model = robot_model_loader.getModel();

  robot_state::RobotStatePtr kinematic_state(new robot_state::RobotState(kinematic_model));

  robot_state::JointStateGroup* joint_state_group = kinematic_state->getJointStateGroup("manipulator");

  while(!service_client.exists())

  {

    ROS_INFO("Waiting for service");

    sleep(1.0);

  }

  moveit_msgs::GetPositionIK::Request service_request;

  moveit_msgs::GetPositionIK::Response service_response;

  service_request.ik_request.robot_state.joint_state.name = joint_state_group->getJointModelGroup()->getJointModelNames();

  service_request.ik_request.group_name = "manipulator";

  service_request.ik_request.pose_stamped.header.frame_id = "torso_roll_link";  

  service_request.ik_request.pose_stamped.pose.position.x = 0.0228744447231;

  service_request.ik_request.pose_stamped.pose.position.y =  -0.498571574688;

  service_request.ik_request.pose_stamped.pose.position.z = -0.898984670639;

  

service_request.ik_request.avoid_collisions = true;  

  /* Call the service */

  service_client.call(service_request, service_response);

  ROS_INFO_STREAM("Result: " << ((service_response.error_code.val == service_response.error_code.SUCCESS) ? "True " : "False ") << service_response.error_code.val);

  /* Filling in a seed state */

  

  /* Visualize the result*/

  moveit_msgs::DisplayRobotState msg;

  joint_state_group->setVariableValues(service_response.solution.joint_state);  

  robot_state::robotStateToRobotStateMsg(*kinematic_state, msg.state);

  robot_state_publisher.publish(msg);

  //Sleep to let the message go through

  ros::Duration(2.0).sleep();  

  

  ros::shutdown();  

  return 0;

}

I always get this error code 21 returned. Any idea why it is doing that?.

Karthik

[Ioan Sucan]

Hello Kathik,

Error -21 means FRAME_TRANSFORM_FAILURE (from MoveItErrorCodes.msg)

Does the "torso_roll_link" frame exist in your model? Maybe try different frames of reference?

Ioan