6-Axis Arm#

Introduction #

The VEX 6-Axis Robotic Arm moves an end effector in three-dimensional space, controls the end effector’s orientation, and works with attached tools such as the Magnet Pickup Tool or Pen Holder Tool.

Below is a list of all available methods:

Actions — Move the 6-Axis Arm to positions or orientations.

move_to — Moves the end effector to a specified x, y, and z coordinate.
move_inc — Moves the end effector by a specified distance from its current position.
move_end_effector_to — Rotates the end effector to a specified yaw, roll, and pitch orientation.
move_end_effector_inc — Rotates the end effector by a specified yaw, roll, and pitch amount.

Mutators — Configure movement, tools, and control settings.

set_speed — Sets the movement speed used by the 6-Axis Arm.
set_end_effector_type — Sets the type of end effector attached to the 6-Axis Arm.
set_end_effector_magnet — Engages or releases the Magnet Pickup Tool.
set_pen_offset — Sets the z-axis offset used with the Pen Holder Tool.
set_control_stop — Enables control stop for the 6-Axis Arm.
set_timeout — Sets the timeout used by 6-Axis Arm movement methods.

Getters — Return motion status, position, orientation, and connection values.

is_done — Returns whether the 6-Axis Arm has finished moving.
get_x — Returns the current x position of the end effector.
get_y — Returns the current y position of the end effector.
get_z — Returns the current z position of the end effector.
get_pitch — Returns the current pitch of the end effector.
get_roll — Returns the current roll of the end effector.
get_yaw — Returns the current yaw of the end effector.
can_arm_reach_to — Returns whether the 6-Axis Arm can reach a specified position.
can_arm_reach_inc — Returns whether the 6-Axis Arm can move by a specified distance.
can_end_effector_reach_to — Returns whether the end effector can reach a specified orientation.
can_end_effector_reach_inc — Returns whether the end effector can rotate by a specified amount.
get_timeout — Returns the current timeout value used by movement methods.
is_connected — Returns whether the 6-Axis Arm is connected to the Brain.

Callbacks — Run functions when arm events occur.

control_stopped — Registers a function to run when control stop is enabled.

Constructor — Manually create a 6-Axis Arm object.

Arm — Creates a 6-Axis Arm object.

This page is for using the 6-Axis Arm on its own with the CTE Tile. To use the 6-Axis Arm with other CTE Workcell components, such as Pneumatics or Conveyors, connect the 6-Axis Arm to an EXP Brain and use the corresponding EXP Arm page.

Actions #

move_to #

move_to moves the 6-Axis Arm to a specified x, y, and z coordinate.

The x, y, and z coordinates describe the position of the end effector in three-dimensional space. Use can_arm_reach_to before this method if the target position may be outside the 6-Axis Arm’s reachable workspace.

Usage:
arm.move_to(x, y, z, wait)

Parameter	Description
`x`	The x-coordinate of the target position in millimeters.
`y`	The y-coordinate of the target position in millimeters.
`z`	The z-coordinate of the target position in millimeters.
`wait`	Optional. `wait=True` (default) makes the project wait until the movement is complete before continuing. `wait=False` starts the movement and immediately continues to the next line of code.

# Move the 6-Axis Arm to (40, 140, 210)
arm.move_to(40, 140, 210)

# Start moving, then print the y-position while the arm moves
arm.move_to(-100, 200, 100, wait=False)

while not arm.is_done():
    brain.print(arm.get_y())
    brain.next_line()
    wait(0.25, SECONDS)

move_inc #

move_inc moves the 6-Axis Arm by a specified distance from its current position along the x, y, and z axes.

Use this method to move relative to where the end effector is now. Use can_arm_reach_inc before this method if the movement may place the 6-Axis Arm outside its reachable workspace.

Usage:
arm.move_inc(x, y, z, wait)

Parameter	Description
`x`	The distance to move along the x-axis in millimeters.
`y`	The distance to move along the y-axis in millimeters.
`z`	The distance to move along the z-axis in millimeters.
`wait`	Optional. `wait=True` (default) makes the project wait until the movement is complete before continuing. `wait=False` starts the movement and immediately continues to the next line of code.

# Move the 6-Axis Arm 100 millimeters along the y-axis
arm.move_inc(0, 100, 0)

move_end_effector_to #

move_end_effector_to rotates the 6-Axis Arm’s end effector to a specified yaw, roll, and pitch orientation.

Orientation describes how the end effector is rotated. yaw rotates around the z-axis, roll rotates around the x-axis, and pitch rotates around the y-axis.

Usage:
arm.move_end_effector_to(yaw, roll, pitch, wait)

Parameter	Description
`yaw`	The target yaw angle, in degrees.
`roll`	The target roll angle, in degrees.
`pitch`	The target pitch angle, in degrees.
`wait`	Optional. `wait=True` (default) makes the project wait until the movement is complete before continuing. `wait=False` starts the movement and immediately continues to the next line of code.

# Rotate the end effector to 90 degrees of roll
arm.move_end_effector_to(0, 90, 0)

move_end_effector_inc #

move_end_effector_inc rotates the 6-Axis Arm’s end effector by a specified yaw, roll, and pitch amount from its current orientation.

Use this method to rotate relative to the end effector’s current yaw, roll, or pitch.

Usage:
arm.move_end_effector_inc(yaw, roll, pitch, wait)

Parameter	Description
`yaw`	The change in yaw, in degrees.
`roll`	The change in roll, in degrees.
`pitch`	The change in pitch, in degrees.
`wait`	Optional. `wait=True` (default) makes the project wait until the movement is complete before continuing. `wait=False` starts the movement and immediately continues to the next line of code.

# Rotate the end effector -50 degrees in pitch
arm.move_end_effector_inc(0, 0, -50)

Mutators #

set_speed #

set_speed sets the movement speed used by the 6-Axis Arm for movement methods.

The 6-Axis Arm speed is set to 50% at the start of a project.

Usage:
arm.set_speed(speed)

Parameter	Description
`speed`	The movement speed of the 6-Axis Arm, from `1` to `100` percent.

# Set the 6-Axis Arm speed to 30%
arm.set_speed(30)

set_end_effector_type #

set_end_effector_type sets the type of end effector attached to the 6-Axis Arm.

When the end effector type is changed, the 6-Axis Arm automatically adjusts its z-offset to match the selected tool. The end effector type is set to MAGNET at the start of a project.

Usage:
arm.set_end_effector_type(type)

Parameter	Description
`type`	The tool attached to the 6-Axis Arm: `MAGNET` (Magnet Pickup Tool) or `PEN` (Pen Holder Tool).

# Set the end effector type to the Pen Holder Tool
arm.set_end_effector_type(PEN)

set_end_effector_magnet #

set_end_effector_magnet engages or releases the Magnet Pickup Tool.

The magnet state stays active until another set_end_effector_magnet method changes it. The magnet state is reset to False at the start of a project.

Usage:
arm.set_end_effector_magnet(state)

Parameter	Description
`state`	The Magnet Pickup Tool state: `True` to pick up and hold objects or `False` to drop any held object and stop picking up new objects.

# Pick up objects and then drop them
arm.set_end_effector_type(MAGNET)
arm.set_end_effector_magnet(True)
wait(2, SECONDS)
arm.set_end_effector_magnet(False)

set_pen_offset #

set_pen_offset sets the z-axis offset used when the Pen Holder Tool is attached to the 6-Axis Arm.

Set the end effector type to PEN before using this method. If the Pen Holder Tool is not selected, this method has no effect.

The pen offset is the distance from the top of the Pen Holder Tool to the tip of the Dry-Erase Marker. At the start of a project, the pen offset is set to 0. A pen offset of 0 places the arm’s z-axis origin at the point where the Pen Holder Tool connects to the 6-Axis Arm.

Usage:
arm.set_pen_offset(zOffset)

Parameter	Description
`zOffset`	The pen offset value in millimeters.

# Set the end effector type to the Pen Holder Tool and set the pen offset
arm.set_end_effector_type(PEN)
arm.set_pen_offset(25)

set_control_stop #

set_control_stop enables control stop for the 6-Axis Arm.

When control stop is enabled, the 6-Axis Arm immediately stops any movement and will not run any further Arm movement methods until the project is restarted.

Usage:
arm.set_control_stop(state)

Parameter	Description
`state`	Optional. `True` (default) enables control stop. `False` does not enable control stop.

# Stop the 6-Axis Arm and prevent further movement
arm.set_control_stop()

set_timeout #

set_timeout sets the timeout value used when moving the 6-Axis Arm.

If a movement does not finish before the timeout is reached, the project continues to the next line of code.

Usage:
arm.set_timeout(timeout, units)

Parameter	Description
`timeout`	The new timeout value.
`units`	Optional. The time unit: `MSEC` (milliseconds, default), `SECONDS`, or `SEC`.

# Set the 6-Axis Arm timeout to 2 seconds
arm.set_timeout(2, SECONDS)

Getters #

is_done #

is_done returns whether the 6-Axis Arm has finished moving.

This method is useful after a movement method is called with wait=False.

True — The 6-Axis Arm has finished moving.
False — The 6-Axis Arm is still moving.

Usage:
arm.is_done()

Parameters	Description
	This method has no parameters.

# Display the 6-Axis Arm's y-position while it moves
arm.move_to(-100, 200, 100, wait=False)

while not arm.is_done():
    brain.print(arm.get_y())
    brain.next_line()
    wait(0.25, SECONDS)

get_x #

get_x returns the current x position of the end effector in millimeters.

Use this method to read where the end effector is currently located along the x-axis.

Usage:
arm.get_x()

Parameters	Description
	This method has no parameters.

# Print the current x position of the 6-Axis Arm
brain.print(arm.get_x())

get_y #

get_y returns the current y position of the end effector in millimeters.

Use this method to read where the end effector is currently located along the y-axis.

Usage:
arm.get_y()

Parameters	Description
	This method has no parameters.

# Print the current y position of the 6-Axis Arm
brain.print(arm.get_y())

get_z #

get_z returns the current z position of the end effector in millimeters.

Use this method to read where the end effector is currently located along the z-axis.

Usage:
arm.get_z()

Parameters	Description
	This method has no parameters.

# Print the current z position of the 6-Axis Arm
brain.print(arm.get_z())

get_pitch #

get_pitch returns the current pitch of the end effector in degrees.

Usage:
arm.get_pitch()

Parameters	Description
	This method has no parameters.

# Print the current pitch of the end effector
brain.print(arm.get_pitch())

get_roll #

get_roll returns the current roll of the end effector in degrees.

Usage:
arm.get_roll()

Parameters	Description
	This method has no parameters.

# Print the current roll of the end effector
brain.print(arm.get_roll())

get_yaw #

get_yaw returns the current yaw of the end effector in degrees.

Usage:
arm.get_yaw()

Parameters	Description
	This method has no parameters.

# Print the current yaw of the end effector
brain.print(arm.get_yaw())

can_arm_reach_to #

can_arm_reach_to returns whether the 6-Axis Arm can move the end effector to a specified x, y, and z coordinate.

Use this method to check a target position before using move_to.

True — The 6-Axis Arm can reach the requested position.
False — The 6-Axis Arm cannot reach the requested position.

Usage:
arm.can_arm_reach_to(x, y, z)

Parameter	Description
`x`	The x-coordinate of the target position in millimeters.
`y`	The y-coordinate of the target position in millimeters.
`z`	The z-coordinate of the target position in millimeters.

# Move the 6-Axis Arm to (100, -20, 50) if it can reach
if arm.can_arm_reach_to(100, -20, 50):
    arm.move_to(100, -20, 50)

can_arm_reach_inc #

can_arm_reach_inc returns whether the 6-Axis Arm can move the end effector by a specified x, y, and z distance from its current position.

Use this method to check a relative movement before using move_inc.

True — The 6-Axis Arm can make the requested movement.
False — The 6-Axis Arm cannot make the requested movement.

Usage:
arm.can_arm_reach_inc(x, y, z)

Parameter	Description
`x`	The distance to move along the x-axis in millimeters.
`y`	The distance to move along the y-axis in millimeters.
`z`	The distance to move along the z-axis in millimeters.

# Increment the 6-Axis Arm 100 mm along the x-axis if possible
if arm.can_arm_reach_inc(100, 0, 0):
    arm.move_inc(100, 0, 0)

can_end_effector_reach_to #

can_end_effector_reach_to returns whether the end effector can rotate to a specified yaw, roll, and pitch orientation.

Use this method to check a target orientation before using move_end_effector_to.

True — The end effector can reach the requested orientation.
False — The end effector cannot reach the requested orientation.

Usage:
arm.can_end_effector_reach_to(yaw, roll, pitch)

Parameter	Description
`yaw`	The target yaw angle, in degrees.
`roll`	The target roll angle, in degrees.
`pitch`	The target pitch angle, in degrees.

# Rotate the end effector to 90 degrees of roll if possible
if arm.can_end_effector_reach_to(0, 90, 0):
    arm.move_end_effector_to(0, 90, 0)

can_end_effector_reach_inc #

can_end_effector_reach_inc returns whether the end effector can rotate by a specified yaw, roll, and pitch amount from its current orientation.

Use this method to check a relative orientation movement before using move_end_effector_inc.

True — The end effector can make the requested rotation.
False — The end effector cannot make the requested rotation.

Usage:
arm.can_end_effector_reach_inc(yaw, roll, pitch)

Parameter	Description
`yaw`	The change in yaw, in degrees.
`roll`	The change in roll, in degrees.
`pitch`	The change in pitch, in degrees.

# Increment the end effector by 10 degrees of pitch if possible
if arm.can_end_effector_reach_inc(0, 0, 10):
    arm.move_end_effector_inc(0, 0, 10)

get_timeout #

get_timeout returns the timeout value used by 6-Axis Arm movement methods in milliseconds.

Usage:
arm.get_timeout()

Parameters	Description
	This method has no parameters.

# Print the current movement timeout in milliseconds
brain.print(arm.get_timeout())

is_connected #

is_connected returns whether the 6-Axis Arm is connected to the Brain.

True — The 6-Axis Arm is connected to the Brain.
False — The 6-Axis Arm is not connected to the Brain.

Usage:
arm.is_connected()

Parameters	Description
	This method has no parameters.

# Print whether the 6-Axis Arm is connected
brain.print(arm.is_connected())

Callbacks #

control_stopped #

control_stopped registers a function that runs when control stop is enabled.

This method returns an instance of the Event class.

Usage:
arm.control_stopped(callback, arg)

Parameter	Description
`callback`	A previously defined function that runs when control stop is enabled.
`arg`	Optional. A tuple containing arguments to pass to the callback function. See Using Functions with Parameters for more information.

# Define a function to run when control stop is enabled
def when_control_stopped():
    brain.print("The arm has been control stopped")

# Run when_control_stopped when the 6-Axis Arm is control stopped
arm.control_stopped(when_control_stopped)

Constructors #

Arm #

Arm creates a 6-Axis Arm object.

Usage:
Arm()

Parameters	Description
	This constructor has no parameters.

# Construct a 6-Axis Arm named arm with the Arm class
arm = Arm()