Introduction

Demo:

Dependencies

• Ubuntu 18.04, 20.04
• ROS melodic
• universal_robot

Installation

cd ~/catkin_ws/src
git clone [email protected]:haxhimitsu/iksolver_track.git
rosdep install -i --from-paths path-to-ros-package
cd ~/catkin_ws
catkin_make
source devel/setup.bash

Launch file

• Cartesian position controller.
  • input : target frame(pose,orientation) from joy stick
  • output : each targt joit potision solved track_ik

roslaunch trac_ik_examples send_joy_frame.launch mode:=position

mode:=position
upload joy node and realtime ik solver.
target frame input from joy stick is directory sent realtime_ik node.\

realtime ik solver node istrac_ik_jointpub.cpp

• Cartesian position and force controller

  • input : target frame(pose,orientation) and force(each axis x,y,z)
  • target frame treat with pose_and_force_PID_controller

  roslaunch trac_ik_examples send_joy_frame.launch mode:=position_and_force
  

  and run position and force PID controller.

  rosrun trac_ik_examples pos_force_controller
  

  Requirements

  In order to publish target frame, you have to prepare joystick controller

  If you don't have joy stick controller, you can publish message from terminal

  for position controll

  • send target frame
    • msg_type:geometry_msgs/PoseStamped
    • send to : /end_effector_pose

  rostopic pub -r 500 /end_effector_pose geometry_msgs/PoseStamped "header:
  seq: 0
  stamp:
      secs: 0
      nsecs: 0
  frame_id: 'base_link'
  pose:
  position:
      x: 0.56
      y: 0.028
      z: 0.611
  orientation:
      x: 0.0
      y: 0.0
      z: 0.0
      w: 1.0"
  

  and you run

  rosrun  trac_ik_examples trac_ik_jointpub
  

  instead of roslaunch trac_ik_examples send_joy_frame.launch mode:=position

for position and force controller

• send target frame and force.

  • msg_type:std_msgs_Float32MultiArray
  • send to :\array

  rostopic pub  -r 500 /array std_msgs/Float32MultiArray "layout:
  dim:
  - label: ''
      size: 10
      stride: 0
  data_offset: 0
  data:
  - 0.56
  - 0.028
  - 0.611
  - 0.0
  - 0.0
  - 0.0
  - 1.0
  - 0.0
  - 0.0
  - 0.00
  "
  

  and run

  rosrun trac_ik_examples pos_force_controller
  

  finally run ik_solver

  rosrun trac_ik_examples trac_ik_jointpub
  

  instead of roslaunch trac_ik_examples send_joy_frame.launch mode:=position_and_force

• Note : each valuable set as

    rostopic pub  -r 500 /array std_msgs/Float32MultiArray "layout:
    dim:
    - label: ''
        size: 10
        stride: 0
    data_offset: 0
    data:
    - pose.x
    - pose.y
    - pose.z
    - rotation.x
    - rotation.y
    - rotation.z
    - rotation.w
    - force.x
    - force.y
    - force.z
    "
  

  force ranges limited -9<value<9 at pos_force_controller.cpp

How to set joint limit

if you use roslaunch ur_gazebo ur5.launch limited:=true, IK provide multiple result. For this reason, Robot may be vibrate.

One of the most simple solution is editing joint limits at ur5_joint_limited_robot.urdf.xacro.

  <!-- arm -->
  <xacro:ur5_robot prefix="" joint_limited="true"
    shoulder_pan_lower_limit="${-pi/4.0}" shoulder_pan_upper_limit="${pi/4.0}"
    shoulder_lift_lower_limit="${-pi}" shoulder_lift_upper_limit="${pi*0.0}"
    elbow_joint_lower_limit="${-pi*0.0}" elbow_joint_upper_limit="${pi}"
    wrist_1_lower_limit="${-pi*1.3}" wrist_1_upper_limit="${-pi/3.0}"
    wrist_2_lower_limit="${-pi}" wrist_2_upper_limit="${pi*0.0}"
    wrist_3_lower_limit="${-pi}" wrist_3_upper_limit="${pi}"
    transmission_hw_interface="$(arg transmission_hw_interface)"
  />

Reference

• This repository reference trac_ik