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IMPORTANT

After this kinova-ros release, the previous ROS release, which mainly developed for jaco arm will be named as "jaco-ros"; and the previous "master" branch is renamed as "jaco-ros-master" branch. Users can keep both "jaco-ros" and new release "kinova-ros" as two parallel stacks. However, further update and support will be only available on "kinova-ros".

KINOVA-ROS

The kinova-ros stack provides a ROS interface for the Kinova Robotics JACO, JACO2 and MICO robotic manipulator arms, and it is built to support further kinova products as well. Besides widely support of Kinova products, there are many bug fixing, improvements and new features as well. The stack is developped upon the Kinova C++ API functions, which communicates with the DSP inside robot base. The stack mainly contains the following packages:

file system

  • kinova_bringup: launch file to start kinova_driver and apply some configurations

  • kinova_driver: most essential files to run kinova-ros stack. Under the include folder, Kinova C++ API headers are defined in ../indlude/kinova, and ROS package header files are in kinova_driver folder. kinova_api source file is a wrap of Kinova C++ API, and kinova_comm builds up the fundamental functions. Some advanced accesses regarding to force/torque control are only provided in kinova_api. Most parameters and topics are created in kinova_arm. A generous archeteture from low level up could be: DSP --communicate--> Kinova C++ API --wrapped--> kinova_api --> kinova_comm --> {kinova_arm; kinova_fingers_action; kinova_joint_angles_action; ...} --> kinova_arm_driver. It is not recommaned to modify kinova_comm and any level below.

  • kinova_demo: python scripts for actionlibs in joint space and cartesian space.

  • kinova_msgs: all the messages, servers and actionlib format are defined here.

  • kinova_description: robot urdf models and meshes are stored here. display_kinova_robot.launch can run without having a robot.

  • kinova_docs: kinova_comm reference html files generated by doxygen. The comments are based on the reference of Kinova C++ API, and some additional information is provided. The documents of Kinova C++ API are automatically installed while installing Kinova SDK from Kinova website "http://www.kinovarobotics.com/service-robotics/products/software/"

Installation

To make kinova-ros part of your workspace, follow these steps (assuming your workspace is setup following the standard conventions):

cd ~/catkin_ws/src
git clone https://github.com/Kinovarobotics/kinova-ros.git kinova-ros
cd ~/catkin
catkin_make

To access the arm via usb copy the udev rule file 10-kinova-arm.rules from ~/catkin_ws/src/kinova-ros/kinova_driver/udev to /etc/udev/rules.d/:

sudo cp kinova_driver/udev/10-kinova-arm.rules /etc/udev/rules.d/

How to use the stack

launch driver

kinova_robot.launch in kinova_bringup folder launches the essential drivers and configurations for kinova robots. kinova_robot.launch has two arguments:

kinova_robotType specifies which robot type is used. For better supporting wider range of robot configurations, robot type is defined by a char[8], in the format of: [{j|m|r|c}{1|2}{s|n}{4|6|7}{s|a}{2|3}{0}{0}]. Robot category {j|m|r|c} refers to jaco, mico, roco and customized, version is {1|2} for now, wrist type {s|n} can be spherical or non-spherical, Degree of Freedom is possible to be {4|6|7}, robot mode {s|a} can be in service or assistive, robot hand {2|3} may equipped with 2 fingers or 3 fingers gripper. Last two positions are undifined and reserved for further features.

eg: j2n6a300 (default value) refers to jaco v2 6DOF assistive 3 fingers. Please be aware that not all options are valided for different robot types.

use_urdf specifies whether the kinematic solution is provided by the URDF model.

When use_urdf:=true (default value), the kinematic solution is automatically solved by URDF model. The robot can be virtually presented in the Rviz and the frames in Rviz are located at each joints. To visulize the robot in Rviz, run $ rosrun rviz rviz, and select root as the world frame. The robot model will synchronize the motion with the real robot.

If use_urdf:=false, the kinematic solution is as ame as the DSP code inside robot. Node kinova_tf_updater will be activated to publish frames, and the frames are defined according the classic D-H converntion(frame may not locat at joints). Even you are not able to visulize the robot properly in Rviz, you are able to observe the D-H frames in Rviz.

eg: roslaunch kinova_bringup kinova_robot.launch kinova_robotType:=m1n4a200 use_urdf:=true

If the robot is not able to move after boot, please try to home the arm by either pressing home button on the joystick or calling rosservice in the ROS service commands below.

Joint position control

Joint position control can be realized by calling KinovaComm::setJointAngles() in customized node, or you may simply call the node joints_action_client.py in the kinova_demo package. Help information is availabe with -h option. The joint position can be commanded by {degree | radian}, relative or absolute value by option -r. The following code will drive the 4th joint of a 4DOF mico robot rotate +10 degree (not to 10 degree), and print additional information about the joint position.

eg: rosrun kinova_demo joints_action_client.py -v -r m1n4a200 degree -- 0 0 0 10

Joint position can be observed by echoing two topics: /'${kinova_robotType}_driver'/out/joint_angles (in degree) and /'${kinova_robotType}_driver'/out/state/position (in radians including finger information)

eg: rostopic echo -c /m1n4a200_driver/out/joint_state will print out joint names, velocity and effort information. However, the effort is a place holder for further verstion.

Another way to control joint position is to use interactive markers in Rviz. Please follow the steps below to active interactive control:

  • launch the drivers: roslaunch kinova_bringup kinova_robot.launch kinova_robotType:=m1n4a200
  • start the node of interactive conrol: rosrun kinova_driver kinova_interactive_control m1n4a200
  • open Rviz: rosrun rviz rviz
  • On left plane of Rviz, Add InteractiveMarkers, click on the right of Updated Topic of added interactive marker, and select the topic /m1n4a200_interactive_control_Joint/update
  • Now a ring should appear at each joint location, and you can move the robot by drag the rings.

Cartesian position control

Cartesian position control can be realized by calling KinovaComm::setCartesianPosition() in customized node, or you may simply call the node pose_action_client.py in the kinova_demo package. Help information is availabe with -h option. The unit of position command can be by {mq | mdeg | mrad}, which refers to meter&Quaternion, meter&degree and meter&radian. The unit of position is always meter, and the unit of orientation is different. Degree and radian are regarding to Euler Angles in XYZ order. Please be aware that the length of parameters are different when use Quaternion and Euler Angles. With the option -v on, positions in other unit format are printed for convenience. The following code will drive a mico robot to move along +x axis for 1cm and rotate hand for +10 degree along hand axis. The last second 10 will be ignored since 4DOF robot cannot rotate along y axis.

eg: rosrun kinova_demo pose_action_client.py -v -r m1n4a200 mdeg -- 0.01 0 0 0 10 10

The Cartesian coordinate of robot root frame is defined by the following rules:

  • origin is the intersection point of the bottom plane of the base and cylinder center line.
  • +x axis is directing to the left when facing the base panel (where power switch and cable socket locate).
  • +y axis is towards to user when facing the base panel.
  • +z axis is upwards when robot is standing on a flat surface.

The current Cartesian position is published via topic: /'${kinova_robotType}_driver'/out/tool_pose In addition, the wrench of end-effector is published via topic: /'${kinova_robotType}_driver'/out/tool_wrench

Another way to control Cartesian position is to use interactive markers in Rviz. Please follow the steps below to active interactive control:

  • launch the drivers: roslaunch kinova_bringup kinova_robot.launch kinova_robotType:=m1n4a200
  • start the node of interactive conrol: rosrun kinova_driver kinova_interactive_control m1n4a200
  • open Rviz: rosrun rviz rviz
  • On left plane of Rviz, Add InteractiveMarkers, click on the right of Updated Topic of added interactive marker, and select the topic /m1n4a200_interactive_control_Cart/update
  • Now a cubic with 3 axis (translation) and 3 rings(rotation) should appear at the end-effector, and you can move the robot by drag the axis or rings.

Finger position control

Cartesian position control can be realized by calling KinovaComm::setFingerPositions() in customized node, or you may simply call the node fingers_action_client.py in the kinova_demo package. Help information is availabe with -h option. The unit of finger command can be by {turn | mm | percent}, which refers to turn of motor, milimeter and percentage. The finger is essentially controlled by turn, and the rest units are propotional to turn for convenience. The value 0 indicates fully open, while finger_maxTurn represents a fully close. The value of finger_maxTurn may vary due to many factors. A proper reference value for finger turn will be 0 (fully-open) to 6400 (fully-close) If necessary, please modify this variable in the code. With the option -v on, positions in other unit format are printed for convenience. The following code fully close the fingers.

eg: rosrun kinova_demo fingers_action_client.py m1n4a200 percent -- 100 100

The finger position is published via topic: /'${kinova_robotType}_driver'/out/finger_position

Velocity Control (joint space and Cartesian space)

The user have access to both joint velocity and Cartesian velocity (linear velocity and angular velocity). The joint velocity control can be realized by publishing to topic /'${kinova_robotType}_driver'/in/joint_velocity. The following command can move the 4th joint of a mico robot at a rate of approximate 10 degree/second. Please be aware that the publishing rate dose effect the motion speed much.

eg: rostopic pub -r 100 /m1n4a200_driver/in/joint_velocity kinova_msgs/JointVelocity "{joint1: 0.0, joint2: 0.0, joint3: 0.0, joint4: 10.0}"

For Cartesian linear velocity, the unit is meter/second. Definition of angular velocity "Omega" is based on the skew-symmetric matrices "S = R*R^(-1)", where "R" is the rotation matrix. angular velocity vector "Omega = [S(3,2); S(1,3); S(2,1)]". The unit is radian/second. An example is given below:

eg: rostopic pub -r 100 /m1n4a200_driver/in/cartesian_velocity kinova_msgs/PoseVelocity "{twist_linear_x: 0.0, twist_linear_y: 0.0, twist_linear_z: 0.0, twist_angular_x: 0.0, twist_angular_y: 0.0, twist_angular_z: 10.0}"

The motion will stop once the publish on the topic is finished. Please be caution when use velocity control as it is a continuous motion unless you stopped it.

** Note on publish frequency ** The joint velocity is set to publish at a frequency of 100Hz, due to the DSP inside the robot loops each 10ms. Any higher frequency will not have any influence to the speed. However, it will fills up a buffer (size of 2000) and the robot may continue to move a bit even stops receiving velocity topic. For a frequency lower than 100Hz, the robot will not able to achieve the requested velocity.

Therefore, the publishing rate at 100Hz is not an optional argument, but a requirement.

ROS service commands

User can home the robot by the command below. It takes no argument and bring robot to pre-defined home position. The command support customized home position that user defined by SDK or JacoSoft as well. /'${kinova_robotType}_driver'/in/home_arm

User can also enable and disable the ROS motion command via rosservice /'${kinova_robotType}_driver'/in/start and /'${kinova_robotType}_driver'/in/stop. When stop is called, robot command from ROS will not able to drive robot until start is called. However, joystick still has the control during this phase.

Force control

The admittance force control can be actived by command rosservice call /'${kinova_robotType}_driver'/in/start_force_control and disabled by rosservice call /'${kinova_robotType}_driver'/in/stop_force_control. The user is able to move the robot by appling force/torque to the end-effector/joints. When there is a Cartesian/joint position command, the result motion will be a combination of both force and position command.

However, it is very important to regulate the force sensor before using force/torque control. The regulation can be achieved by set 180 degree to all the joints (robot will stand straight up for most of its links). Then, send zero torques to all by SDK, JacoSoft or API functions. SDK may not function well in certain cases. Therefore, it is better to use other two ways.

What's new comparison to JACO-ROS

  • migrate from jaco to kinova in the scope of: file names, class names, function names, data type, node, topic, etc.
  • apply kinova_RobotType for widely support
  • Re-define JointAngles for consistence
  • updated API version with new features
  • Create transform between different Euler Angle definitions in DSP and ROS
  • Criteron check when if reach the goal
  • URDF models for all robotTypes
  • Interactive for joint control
  • New message for KinovaPose
  • More options for actionlibs arguments, etc.
  • Relative motion control
  • Kinematic solution to be consistant with robot base code.
  • Fix joint offset bug for joint2 and joint6
  • Fix joint velocity control and position velocity control

Notes and Limitations

  1. Force/torque control is only for advanced users. Please be caution when using force/torque control api functions.

  2. The joint_state topic currently reports only the arm position and velocity. Effort is a placeholder for future compatibility. Depending on your firmware version velocity values can be wrong.

  3. When updating the firmware on the arm (e.g., using Jacosoft) the serial number will be set to "Not set" which will cause multiple arms to be unusable. The solution is to make sure that the serial number is reset after updating the arm firmware.

  4. Some virtualization software products are known to work well with this package, while others do not. The issue appears to be related to proper handover of access to the USB port to the API. Parallels and VMWare are able to do this properly, while VirtualBox causes the API to fail with a "1015" error.

  5. Previously, files under kinova-ros/kinova_driver/lib/i386-linux-gnu had a bug which required uses 32-bit systems to manually copy them into devel or install to work. This package has not been tested with 32-bit systems and this workaround may still be required. 64-bit versions seem to be unaffected.

Report a Bug

Any bugs, issues or suggestions may be sent to [email protected].

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