karpal_lib Module

Created on 2016-01-20 @author: Andrew H. Fagg and Bonnie Pope

class karpal_lib.Karpal

Karpal control tools.

Variables:

• robotEnable – Interface for enabling/disabling the robot. See: http://api.rethinkrobotics.com/baxter_interface/html/baxter_interface.robot_enable.RobotEnable-class.html
• leftArm – Interface for the left arm. See: http://api.rethinkrobotics.com/baxter_interface/html/baxter_interface.limb.Limb-class.html
• rightArm – Interface for the right arm. See: http://api.rethinkrobotics.com/baxter_interface/html/baxter_interface.limb.Limb-class.html
• leftGripper – Interface for the left gripper. See: http://api.rethinkrobotics.com/baxter_interface/html/baxter_interface.gripper.Gripper-class.html
• rightGripper – Interface for the right gripper. See: http://api.rethinkrobotics.com/baxter_interface/html/baxter_interface.gripper.Gripper-class.html
• rightArmNavigator – Interface for the right arm navigator (user interface). See: http://api.rethinkrobotics.com/baxter_interface/html/baxter_interface.navigator.Navigator-class.html
• leftArmNavigator – Interface for the left arm navigator (user interface). See: http://api.rethinkrobotics.com/baxter_interface/html/baxter_interface.navigator.Navigator-class.html
• rightTorsoNavigator – Interface for the right torso navigator (user interface). See: http://api.rethinkrobotics.com/baxter_interface/html/baxter_interface.navigator.Navigator-class.html
• leftTorsoNavigator – Interface for the left torso navigator (user interface). See: http://api.rethinkrobotics.com/baxter_interface/html/baxter_interface.navigator.Navigator-class.html
• head – Interface to the head. See: http://api.rethinkrobotics.com/baxter_interface/html/baxter_interface.head.Head-class.html
• leftIkService – Interface to the inverse kinematics service. See: TBD
• rightIkService – Interface to the inverse kinematics service. See: TBD
• ikService – Dict containing both the left and right IK services.
• displayPublisher – Publisher for images being routed to the head display.

JPOSITION_CRANE = {'s1': -0.7853981633974483, 's0': 0, 'w2': 0, 'w1': 0.7853981633974483, 'w0': 0, 'e1': 1.5707963267948966, 'e0': 0}

Crane joint angle position. Elbow up and hand oriented downward.

JPOSITION_GRASP_READY = {'s1': -0.7853981633974483, 's0': 0, 'w2': 0, 'w1': -0.7853981633974483, 'w0': 0, 'e1': 1.5707963267948966, 'e0': 0}

Grasp ready angle position. Elbow up and forearm and hand oriented horizontally (45 degrees off center).

JPOSITION_PARK = {'s1': 0.39269908169872414, 's0': 0, 'w2': 0, 'w1': 0.39269908169872414, 'w0': 0, 'e1': 0.7853981633974483, 'e0': 0}

Park angle position. Arm is in a low-energy state where it is safe to be disabled.

JPOSITION_ZERO = {'s1': 0, 's0': 0, 'w2': 0, 'w1': 0, 'w0': 0, 'e1': 0, 'e0': 0}

Zero joint angle position

armMoveToJointPosition(limb='left', orientation={}, timeout=15.0)

Move arm to a specified joint position.

Parameters:

• limb – ‘left’ or ‘right’
• orientation – dict containing the joint angles of interest. The elements can be either specific joints (including limb) or generic joints. In the latter case, the specified limb is appended
• timeout – Number of seconds to wait for movement to complete (default = 15.0 sec)

calibrateGripper(limb)

Calibrate the specified gripper

Parameters:limb – Side to calibrate. Either ‘left’ or ‘right’

calibrateLeftGripper()

Calibrate the positional offset of the left gripper.

calibrateRightGripper()

Calibrate the positional offset of the right gripper.

closeGripper(limb)

Close the specified gripper until a force threshold.

Parameters:limb – Side to close. Either ‘left’ or ‘right’

closeLeftGripper()

Close the left gripper until a force threshold.

closeRightGripper()

Close the right gripper until a force threshold.

computeHorizontalOrientation(orient, handFlip=0)

Compute a hand orientation in which the hand is in the horizontal plane

Parameters:

• orient – Orientation of the hand in the robots coordinate frame (about Z)
• handFlip – Enables addition of a flipped hand (still horizontal, though) if set to PI

Returns:

Quaternion describing the full orientation

computeVerticalOrientation(orient)

Compute a hand orientation in which the hand is pointed downwards

Parameters:orient – Orientation of the hand in the robot coordinate frame (about Z) Returns:Quaternion describing the full orientation

disable()

Disable the robot.

enable()

Enable the robot.

Note

The robot’s E-Stop button must be disabled in order for this function to be successful (this is the big red button).

findAbsoluteJogSolution(limb='left', deltaX=[0, 0, 0])

Compute the inverse kinematics solution for a small change in position. The change is specified in the robot base coordinate frame.

Parameters:

• limb – Which limb to compute solution for: left/right
• deltaX – Three element array: [dX, dY, dZ]

Returns:

None if no solution is found, or a dictionary that contains information about the chosen solution: the joint angles (joint_angles), the full hand orientation (q), position of the limb (position); and the limb that the solution was computed for (limb).

findHorizontalSolution(limb='left', position=[0.6, 0.1, 0.3], minOrient=1.5707963267948966, maxOrient=1.5707963267948966, nAttempts=10)

Find a viable joint solution for a horizontal reach. A range of acceptable orientations in the horizontal plane is specified; one is selected at random. Multiple attempts are tried at finding a valid inverse kinematics solution (up to nAttemts)

Parameters:

• limb – Determines which limb; ‘left’ or ‘right’
• position – Goal position of the gripper
• minOrient – Minimum acceptable hand orientation (in the horiziontal plane)
• maxOrient – Maximum acceptable hand orientation
• nAttempts – Maximum number of attempts

Returns:

None if no solution is found, or a dictionary that contains information about the chosen configuration: the solution (joint_angles), the full hand orientation (q), the hand orientation in the horizontal plane (orient); and the limb the solution was computed for (limb).

findRelativeJogSolution(limb='left', deltaX=[0, 0, 0])

Compute the inverse kinematics solution for a small change in position. The change is specified in the hand coordinate frame.

Parameters:

• limb – Which limb to compute solution for: left/right
• deltaX – Three element array: [dX, dY, dZ]

Returns:

None if no solution is found, or a dictionary that contains information about the chosen solution: the joint angles (joint_angles), the full hand orientation (q), position of the limb (position); and the limb that the solution was computed for (limb).

findVerticalSolution(limb='left', position=[0.6, 0.1, 0.3], minOrient=0, maxOrient=6.283185307179586, flipFlag=False, nAttempts=10)

Find a viable joint solution for a vertical reach (from above). A range of acceptable orientations about the vertical axis is specified; one is selected at random. Multiple attempts are tried at finding a valid inverse kinematics solution (up to nAttemts)

Parameters:

• limb – Determines which limb; ‘left’ or ‘right’
• position – Goal position of the gripper
• minOrient – Minimum acceptable hand orientation (about the vertical axis)
• maxOrient – Maximum acceptable hand orientation
• nAttempts – Maximum number of attempts

Returns:

None if no solution is found, or a dictionary that contains information about the chosen configuration: the solution (joint_angles), the full hand orientation (q), the hand orientation in the horizontal plane (orient); and the limb the solution was computed for (limb).

getArmOrientation(limb)

Get the orientation of the specified hand (base of the hand) in the Baxter’s main coordinate frame.

Parameters:limb – ‘left’ or ‘right’ Returns:A vector containing the unit quaternion

getArmPose(limb)

Get the full pose of the specified limb.

Parameters:limb – ‘left’ or ‘right’ Returns:A dict containing the full pose (keys: ‘position’ and ‘orientation’).

getArmPosition(limb)

Get the Cartesian position of the specified hand (base of the hand) in the Baxter’s main coordinate frame. :param limb: ‘left’ or ‘right’ :returns: A vector containing the position (m)

getJointAngles(limb)

Get the joint configuration of the specified limb.

Parameters:limb – ‘left’ or ‘right’ Returns:A dict of joint angles (rad).

getLeftArmOrientation()

Get the orientation of the left hand (base of the hand) in the Baxter’s main coordinate frame.

Returns:A vector containing the unit quaternion

getLeftArmPosition()

Get the Cartesian position of the left hand (base of the hand) in the Baxter’s main coordinate frame.

Returns:A vector containing the position (m)

getRightArmOrientation()

Get the orientation of the right hand (base of the hand) in the Baxter’s main coordinate frame.

Returns:A vector containing the unit quaternion

getRightArmPosition()

Get the Cartesian position of the right hand (base of the hand) in the Baxter’s main coordinate frame.

Returns:A vector containing the position (m)

inverseKinematics(limb, position, orientation)

Perform the inverse kinematics given a limb, position and orientation

Parameters:

• limb – ‘left’ or ‘right’
• position – Vector containing the goal Cartesian position for the base of the hand
• orientation – Vector containing the goal orientation for the hand (unit quaternion)

Returns:

None if no solution found, or a dict containing the joint angles that correspond to the goal.

moveArm(limb, position, orientation)

Move the arm to a Cartesian goal position/orientation

Parameters:

• limb – ‘left’ or ‘right’
• position – Vector containing the goal Cartesian position for the base of the hand
• orientation – Vector containing the goal orientation for the hand (unit quaternion)

Returns:

None if no solution found, or a dict containing the joint angles that correspond to the goal.

moveArmJoints(limb, angles, timeout=15.0)

Move specified arm to a joint goal

Parameters:

• limb – ‘left’ or ‘right’
• angles – A dict (?) containing the joint goal position
• timeout – Number of seconds before aborting joint movement (default = 15.0 sec)

Returns:

The joint angles

moveArmUntilDistance(limb='left', delta=0.02, maxDistance=0.3, handDistance=70)

Move the arm along the Z axis of the hand until an obstacle is sensed or a maximum distance is achieved.

Warning

Not all obstacles can be sensed with the distance sensor.

Parameters:

• limb – Determines which limb; ‘left’ or ‘right’
• delta – Distance to move along the Z axis (m) between sensor checks. This parameter should be positive
• maxDistance – Maximum distance to move (m)
• handDistance – Distance to the obstacle to stop at (mm)

Returns:

2 if successfully reached the obstacle; 1 if the maximum distance has been reached; and 0 False if no solution

openGripper(limb)

Open the specified gripper to its widest extent

Parameters:limb – Side to open. Either ‘left’ or ‘right’

openLeftGripper()

Open the left gripper to its widest extent.

openRightGripper()

Open the right gripper to its widest extent.

printTextToScreen(text, scale=3)

Print text to the Baxter screen

Parameters:

• text – String containing the text to print. Newlines in the string are handled properly.
• scale – Size of the text.

tiltWrist(limb)

For the specified limb, flip the final wrist joint by pi radians

Parameters:limb – ‘left’ or ‘right’ Returns:True if successful; False if not

karpal_lib.main()

Test function