Ein contains an interface to connect to and program the Kinova MOVO. To install, create a new workspace with Ein, and the Kinova packages, following the Kinova Setup Instructions.

Installing

Ein will automatically detect the Kinova MOVO packages and compile the MOVO library. You should see a statement to this effect when you run catkin_make in the workspace. If Ein defaults to some other library, this is because it detected another robot first in the ROS_PACKAGE_PATH, such as Baxter or AIBO. In that case, either change the ROS_PACKAGE_PATH to exclude these other packages. Alternatively, edit the Ein CMakefile to only build the MOVO package. (There is an if statement to decide what library to build; just change it to always build MOVO.)

Copy the setup.sh file to the root directory of the workspace. Then run ROBOT=movo2 screen -c src/ein/ein_movo.screenrc. This command will start a screen session that is initialized with the relevant commands and packages. It will also set the ROS_MASTER_URI to movo2. You may need to set your ROS_IP or ROS_HOSTNAME depending on how your network is configured.

Get Started

The relevant words are defined in ein_movo.cpp. Useful ones: movoKill kills the robot (as if you hit the kill switch). The full list of all Ein words can be seen in the words. Example programs using the movo functionality can be seen in movo.back. Below is a brief high-level overview.

The two words moveToTuck and moveToHome move the upper body to the home and tucked position respectively. The words torsoUp and torsoDown move the torso up and down, controlled by torsoGridSize. The words panUp, panDown, tiltUp and tiltDown change the pan/tilt angle by the amount panTiltGridSize.

Arms

Ein has a concept of a focused end effector (either the left or right arm). Ein also has a concept of zero gravity. When zeroGToggle is on, Ein does not set the pose and continuously updates the end effector position of the focused end effector. (It does not update the not-focused end effector, although we could change this.) You can change the focused end effector with incrementEndEffector. Ein has a rich library of words for interacting with the focused end effector, such as xUp, xDown, yUp, yDown. All movement words, such as xUp, localXUp, oXUp and waitUntilAtCurrentPosition work to move the focused end effector using MoveIt. Many of the tutorial instructions for the [[getstarted]] page apply directly to MOVO to move the end effector.

If you want to launch moveit yourself, run the following command on movo2: roslaunch movo_7dof_moveit_config movo_moveit_planning_execution.launch debug:=true.

Gripper

The gripper is sort of complicated. Our Movo has the Jaco kg3 gripper. So there is a joint states topic that has the three finger positions. This is available in Ein as finger1JointPosition, finger1JointVelocity and finger1JointEffort, for each of the three fingers. However there does not appear to be a Movo topic to move the finger joints individually (yet). I have asked them about this on github.

What does exist is an action client that opens and closes the gripper, treating the gripper state as a single double, gripperPosition. This position is computed from the joint angles from two of the three fingers and ranges between 0.01 and 0.165. These are all defined in the movo stack in movo_jtas.py. Ein clones these constants as well as the function that computes the double value you use to command the gripper and has a gripperPosition reactive variable that reflects the current gripper position, computed from the finger joint states.

Using these primitives, it defines openGripper and closeGripper as words, just like Baxter.

Moving the Base in the Odom Frame

To move the base in the odometry frame, you must first run baseGoCfg to send the configuration command to move the base. All these words begin with the string base. 0.1 baseSendXVel sends one twist message with 0.1 in the x direction and 0 in all other fields. The words baseSendYVel sends velocities in the y direction. To rotate the base use 0.1 baseSendOZVel which sends a twist message with the angular speed. Finally, lx ly lz ax ay az baseSendTwist sends a complete twist message. (Note that ax and ay are probably ignored since the base is constrainted to move in the plane.)

In the future, I plan for the odom frame to be another ‘end effector’, with movements that try to assume poses in that frame. It would then let someone move the robot without running gmapper or the like.

Moving the Base in the Map Frame

The third ‘end effector’ is the base. When the base is the focused end effector, the truePose reflects the pose from the TF /map frame. The movement commands such as xUp and the like result in an action being sent to the move_base_navi topic. The base is constrained to move in x, y, and yaw; hence commands such as oXUp and the like will result in the base moving. You need to have set up gmapper with a map and localization and the navigation action following the movo instructions.

There is a known bug that it does not update the currentPose when you switch end effectors, so the pose that Ein tries to move to will still be from the ‘old’ end effector. I plan to make it save the last good current pose when you switch end effectors and write it back when you switch back.

For now, you should switch to zero gravity mode (zeroGToggle), which tells Ein to set the currentPose to the truePose. This will update the currentPose to the end effector’s current position and then the xUp words will start working from there.

Movo Status

There are a variety of reactive variable words that record the robot’s current status. For example, batterySoc contains the battery’s current state of charge from the associated ROS topic. It is continuously updated by reading the ROS topic, so whenever it is accessed, it will automatically reflect the most recent value. (This aspect is what makes it a reactive variable.) There are undoubtaly more such words that should be added. If more are needed, it is straightforward to add a new subscriber and new reactive variable, following the existing examples. Feel free to send a patch.

Moveit Configuration

There are a variety of words to read the current MoveIt state (and a smaller number of setters). These all begin with the string Moveit and refer to the Move Group associated with the current focused end effector. For example, moveitPlanningFrame is the string of the current planning frame. The word moveitGoalPositionTolerance is the tolerance on the goal position, etc.

Sound

The say word takes a string and sends it to the sound_play action. It would be easy to add more words to more directly control the sound playback, but all that exists now is say. For example "Hello world" say causes MOVO to say, “Hello world.”

Light Fields

We plan to connect the Kinect 2 camera to Ein in order to create light field synthetic photographs using Movo. The problem is the frame rate when offboard over wireless is quite slow, so this feature is a pain to add. Movo plans to add faster wifi by the end of summer. Perhaps we can do this now by plugging into the wired ethernet…

Movo Says

Movo can play the children’s game Simon Says!

  • Move to the tuck position and explain the rules with movoSaysBegin
  • Say goodbye with movoSaysEnd
  • All commands are named movoSays. Movo gives a command and executes.
  • Check movo.back for an up-to-date list of commands.
  • To say “Movo Says” before a command, use movoSays movoSaysCommand
  • Use movoSaysStop to move back to the tuck position

TODO

  • set joint targets and positions for the fingers.

  • light fields with the kinect 2. (Our kinect 2 frame rate is realllllly slow.)

  • zero g (reactive mode) as described on github.

  • figuring useful “default” poses for the arms for various tasks. I would like to find default poses for:
    • front reaching (opening a door or cupboard or pushing an elevator)
    • picking up from the floor
    • picking up from the table

  • Try to teleop opening a door.

  • Save joint states; restore joint states.

  • try google cartographer.

  • See if you can map without providing an initial pose.

  • add isBaseMoving, isGripperMoving, isArmMoving, isGripperGripping, etc.

  • add ein joint position control and stuff.