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2015-11-04 04:44:02 -0600 asked a question Read Rosbag into Variable

Hello everyone,

I am trying to read from a rosbag within my c++ node, and store the value of a message in a variable: This is my rosbag info:

path:        moveToPreGraspPosition.bag
version:     2.0
duration:    0.0s
start:       Nov 03 2015 09:50:28.73 (1446544228.73)
end:         Nov 03 2015 09:50:28.73 (1446544228.73)
size:        21.0 KB
messages:    1
compression: none [1/1 chunks]
types:       control_msgs/FollowJointTrajectoryActionGoal [cff5c1d533bf2f82dd0138d57f4304bb]
topics:      /mbot05/cyton_joint_trajectory_action_controller/follow_joint_trajectory/goal   1 msg     : control_msgs/FollowJointTrajectoryActionGoal

So, I have one message of type control_msgs/FollowJointTrajectoryActionGoal and I want to create a variable of this type in my code and store this info in that variable. I followed some tutorials online and this is what I came up with:

actionlib::SimpleActionClient<control_msgs::FollowJointTrajectoryAction> ac("cyton_joint_trajectory_action_controller/follow_joint_trajectory", true);
ac.waitForServer(); //will wait for infinite time

rosbag::Bag bag;
bag.open("/home/catkin_ws/src/pick_place_demo/moveToPreGraspPosition.bag", rosbag::bagmode::Read);

std::vector<std::string> topics;
topics.push_back(std::string("/mbot05/cyton_joint_trajectory_action_controller/follow_joint_trajectory/goal"));
rosbag::View view(bag, rosbag::TopicQuery(topics));

BagSubscriber<control_msgs::FollowJointTrajectoryActionGoal> teste;  

BOOST_FOREACH(rosbag::MessageInstance const m, view)
{
    control_msgs::FollowJointTrajectoryActionGoal::ConstPtr s = m.instantiate<control_msgs::FollowJointTrajectoryActionGoal>();
    if (s != NULL)
    teste.newMessage(s);
}

bag.close();
ac.sendGoal(teste.goal);

//control_msgs::FollowJointTrajectoryActionGoal sd2;
//ac.sendGoal(sd2.goal);

bool finished_before_timeout = ac.waitForResult(ros::Duration(30.0));
if (finished_before_timeout){
    actionlib::SimpleClientGoalState state = ac.getState();
    ROS_INFO("Action finished: %s",state.toString().c_str());
}else{
    ROS_INFO("Action did not finish before the time out.");
}

Where BagSubscriber is defined like this:

template <class M>
class BagSubscriber : public message_filters::SimpleFilter<M>
{
public:
  void newMessage(const boost::shared_ptr<M const> &msg)
  {
    signalMessage(msg);
  }
};

When I run this, however, I cannot access the field "goal" inside my variable because I have the wrong type, giving me a compiling error:

/home/catkin_ws/src/pick_place_demo/src/PickObject.cpp:108:21: error: ‘class BagSubscriber<control_msgs::FollowJointTrajectoryActionGoal_<std::allocator<void> > >’ has no member named ‘goal’

If run the commented lines instead, it compiles smoothly. Do you know how I can copy the contents of my bag topic to my variable so it's clean? If I try other approaches to make s igual to sd2 I usually get this:

no known conversion for argument 1 from ‘control_msgs::FollowJointTrajectoryActionGoal_<std::allocator<void> >::ConstPtr {aka boost::shared_ptr<const control_msgs::FollowJointTrajectoryActionGoal_<std::allocator<void> > >}’ to ‘const control_msgs::FollowJointTrajectoryActionGoal_<std::allocator<void> >&’
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2015-11-03 06:21:56 -0600 asked a question rosbag to variable

HI,

I have saved a rosbag with the goal topic of an action:

...
messages:    1
compression: none [1/1 chunks]
types:       control_msgs/FollowJointTrajectoryActionGoal [cff5c1d533bf2f82dd0138d57f4304bb]
topics:      /robot_joint_trajectory_action_controller/follow_joint_trajectory/goal   1 msg     : control_msgs/FollowJointTrajectoryActionGoal

What I was trying to do was to copy this 1 message to a variable so I can call the service with this saved goal within my cpp node:

rosbag::Bag bag;
bag.open("test.bag", rosbag::bagmode::Read);

std::vector<std::string> topics;
topics.push_back(std::string("/robot_joint_trajectory_action_controller/follow_joint_trajectory/goal"));

rosbag::View view(bag, rosbag::TopicQuery(topics));

foreach(rosbag::MessageInstance const m, view)
{
    control_msgs::FollowJointTrajectoryActionGoal::ConstPtr s = m.instantiate<control_msgs::FollowJointTrajectoryActionGoal>();
    if (s != NULL){
        goal=s;
    }
}

bag.close();

//ac.sendGoal(goal);

//wait for the action to return
bool finished_before_timeout = ac.waitForResult(ros::Duration(30.0));

if (finished_before_timeout)
{
    actionlib::SimpleClientGoalState state = ac.getState();
    ROS_INFO("Action finished: %s",state.toString().c_str());
}
else{
    ROS_INFO("Action did not finish before the time out.");
}

Of course i cannot do s=goal. How to do this?

Thanks!

2015-10-29 13:42:21 -0600 answered a question UR5 velocity control and trajectory recording/replaying

Were you able to find a solution for #2?

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2015-07-20 03:45:37 -0600 asked a question Setting up ROS catkin/rosbuild simultaneously

I have both a catkin_ws and a rosbuild_ws. However, when I use the command roscd I can only go to the one I've sourced last, i.e.:

-When I do source ~/rosbuild_ws/setup.bash, I the packages inside rosbuild are known, hence I can roscd to them.

-When I do ". ~/catkin_ws/devel/setup.bash", the packages inside catkin are known. But I stop being able to roscd into rosbuild.

This also means that rosbuild cannot use catkin packages and vice versa.

What can I do?

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2015-04-27 09:00:30 -0600 asked a question Create element from python class in cpp

This is my workspace

>>Folder1
    >>scr
        >>Gripper.cpp
    >>include
        >>Gripper.h
    >>script
        >>Arm.py

Inside Arm.py , I've got a class ArmClass defined, with some variables and functions. All the code I'm running is inside Gripper.cpp. I need to create a member of ArmClass inside my gripper.cpp. I was reading about this online but I couldn't figure out how to do it and didn't find any information on how to do it in ROS (I only found how to call Cpp classes in python code...)

Thanks

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2015-04-22 02:55:11 -0600 asked a question moveIt control gripper

I was wondering if it is possible to instead of planning positions for the last joint of the arm to go to, if it's possible to do control the end-effector (gripper) position instead... I've been trying to do this for a while but can't figure out how to. thanks

2015-04-21 12:02:12 -0600 received badge  Editor (source)
2015-04-21 11:18:44 -0600 asked a question end-effector constraint with moveIt

Hi,

I’m trying to use move it to move an arm vertically ONLY. The idea is to keep the tip of the end-effector to always keep the x and y-axis position and change the z-axis position in each iteration, keeping its orientation as well. I also want to constrain the movement from start-position to end-position in each iteration to follow this constraints (x and y fixed, z changing only). I don’t care about how much the joints change as long as the gripper (my end-effector) only moves upwards.

I tried to do it as presented bellow, but i don’t see any constraints being followed? What am I doing wrong?

int main(int argc, char **argv){

    ros::init(argc, argv, "move_group_interface_tutorial");
    ros::NodeHandle node_handle;
    ros::AsyncSpinner spinner(1);
    spinner.start();


    /* This sleep is ONLY to allow Rviz to come up */
    sleep(20.0);

    moveit::planning_interface::MoveGroup group_r("right_arm");

    robot_state::RobotState start_state(*group_r.getCurrentState());
    geometry_msgs::Pose start_pose;
    start_pose.orientation.x = group_r.getCurrentPose().pose.orientation.x;
    start_pose.orientation.y = group_r.getCurrentPose().pose.orientation.y;
    start_pose.orientation.z = group_r.getCurrentPose().pose.orientation.z;
    start_pose.orientation.w = group_r.getCurrentPose().pose.orientation.w;
    start_pose.position.x = group_r.getCurrentPose().pose.position.x;
    start_pose.position.y = group_r.getCurrentPose().pose.position.y;
    start_pose.position.z = group_r.getCurrentPose().pose.position.z;

    //const robot_state::JointModelGroup *joint_model_group = start_state.getJointModelGroup(group_r.getName());
    //start_state.setFromIK(joint_model_group, start_pose);
    group_r.setStartState(start_state);

    moveit_msgs::OrientationConstraint ocm;

    ocm.link_name = "r_wrist_roll_link";
    ocm.header.frame_id = "base_link";
    ocm.orientation.w = 0.0;
    ocm.absolute_x_axis_tolerance = 0.0;
    ocm.absolute_y_axis_tolerance = 0.0;
    ocm.absolute_z_axis_tolerance = 0.1;
    ocm.weight = 1.0;
    moveit_msgs::Constraints test_constraints;
    test_constraints.orientation_constraints.push_back(ocm);
    group_r.setPathConstraints(test_constraints);



    geometry_msgs::Pose next_pose = start_pose;
    while(1){
        std::vector<geometry_msgs::Pose> waypoints;
        next_pose.position.z -= 0.03;
        waypoints.push_back(next_pose);  // up and out

        moveit_msgs::RobotTrajectory trajectory;
        double fraction = group_r.computeCartesianPath(waypoints, 0.005, 0.0, trajectory);

        /* Sleep to give Rviz time to visualize the plan. */
        sleep(5.0);
    }


}
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2015-03-24 08:45:51 -0600 commented answer Verify loop_rate

thank you, that was it.

2015-03-24 05:34:30 -0600 commented answer set parameter using launch file

Thank you, that helped!

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2015-03-24 05:32:50 -0600 asked a question Verify loop_rate

I have set a loop rate in the following way:

ros::Rate r(100)
while(ros::Ok()){
    ros::SpinOnce();
    function();
    r.sleep();
}

Is there anyway to verify if I am accomplish this rate or if the function is taking longer than that? Thank you.

2015-03-23 11:03:34 -0600 asked a question set parameter using launch file

I have three different but related questions

1st: Is it possible to set the value of a variable using the launch file? I read about it online but I couldn't understand how to use it.

2nd: I couldn't find anything on how to use the launch file to set the value of a variable in a message. for instance if I have:

mymessagevector.msg:

mymessage myvector[2]

mymessage.msg:

int32 value
string ID

Is there a way to set the myvector[0].ID="ID1" and myvector[1].ID="ID2" and always publish that without having to define it everytime I sent the message to a topic?

3rd: If I don't know how many variables I have and I want to publish each variable in a different topic like /commontopic/var1 ; /commontopic/var2 ; /commontopic/varN , is there a way to achieve this using the terminal? Thank you in advance