RobotPololuPtu¶

class RobotPololuPtu(self: visp._visp.robot.RobotPololuPtu, device: str = /dev/ttyACM0, baudrate: int = 9600, verbose: bool = false)¶

Bases: Robot

Interface for the Pololu Maestro pan-tilt unit using two servo motors.

See https://www.pololu.com/category/102/maestro-usb-servo-controllers for more details.

This class handle the vpPololu class in a higher level and allows to control the pan-tilt unit using position or velocity commands.

The corresponding Denavit-Hartenberg representations of the PTU is the following:

Default constructor.

Parameters:

device: Name of the serial interface used for communication.
baudrate: Baudrate used for the serial communication. Note that this parameter is only used on Windows.
verbose: When true, enable verbose mode.

Methods

`__init__`	Default constructor.
`getAngularVelocityResolution`	Return the minimul angular velocity in rad/s that could be applied to move the motors.
`getPosition`	Overloaded function.
`getPositioningVelocityPercentage`	Get the percentage of the maximum velocity applied to move the PTU in position.
`get_eJe`	Overloaded function.
`get_fJe`	Overloaded function.
`setPosition`
`setPositioningVelocityPercentage`	Set the percentage of the maximum velocity applied to move the PTU in position.
`setRobotState`	Overloaded function.
`setVelocity`
`setVerbose`	Overloaded function.
`stopVelocity`	Stop the velocity command.

Inherited Methods

`STATE_ACCELERATION_CONTROL`
`RobotStateType`	Robot control frames.
`setMaxTranslationVelocity`	Set the maximal translation velocity that can be sent to the robot during a velocity control.
`getRobotState`
`END_EFFECTOR_FRAME`
`CAMERA_FRAME`
`saturateVelocities`	Saturate velocities.
`ARTICULAR_FRAME`
`JOINT_STATE`
`TOOL_FRAME`
`setMaxRotationVelocity`	Set the maximal rotation velocity that can be sent to the robot during a velocity control.
`STATE_STOP`
`STATE_POSITION_CONTROL`
`getMaxTranslationVelocity`	Get the maximal translation velocity that can be sent to the robot during a velocity control.
`ControlFrameType`	Robot control frames.
`getMaxRotationVelocity`	Get the maximal rotation velocity that can be sent to the robot during a velocity control.
`REFERENCE_FRAME`
`STATE_FORCE_TORQUE_CONTROL`
`STATE_VELOCITY_CONTROL`
`getNDof`	Return robot degrees of freedom number.
`MIXT_FRAME`

Operators

`__doc__`
`__init__`	Default constructor.
`__module__`

Attributes

`ARTICULAR_FRAME`
`CAMERA_FRAME`
`END_EFFECTOR_FRAME`
`JOINT_STATE`
`MIXT_FRAME`
`REFERENCE_FRAME`
`STATE_ACCELERATION_CONTROL`
`STATE_FORCE_TORQUE_CONTROL`
`STATE_POSITION_CONTROL`
`STATE_STOP`
`STATE_VELOCITY_CONTROL`
`TOOL_FRAME`
`__annotations__`

class ControlFrameType(self, value: int)¶

Bases: pybind11_object

Robot control frames.

Values:

REFERENCE_FRAME: Corresponds to a fixed reference frame attached to the robot structure.
ARTICULAR_FRAME: Corresponds to the joint state. This value is deprecated. You should rather use vpRobot::JOINT_STATE .
JOINT_STATE: Corresponds to the joint state.
END_EFFECTOR_FRAME: Corresponds to robot end-effector frame.
CAMERA_FRAME: Corresponds to a frame attached to the camera mounted on the robot end-effector.
TOOL_FRAME: Corresponds to a frame attached to the tool (camera, gripper…) mounted on the robot end-effector. This value is equal to vpRobot::CAMERA_FRAME .
MIXT_FRAME: Corresponds to a “virtual” frame where translations are expressed in the reference frame, and rotations in the camera frame.

__and__(self, other: object) → object¶

__eq__(self, other: object) → bool¶

__ge__(self, other: object) → bool¶

__getstate__(self) → int¶

__gt__(self, other: object) → bool¶

__hash__(self) → int¶

__index__(self) → int¶

__init__(self, value: int)¶

__int__(self) → int¶

__invert__(self) → object¶

__le__(self, other: object) → bool¶

__lt__(self, other: object) → bool¶

__ne__(self, other: object) → bool¶

__or__(self, other: object) → object¶

__rand__(self, other: object) → object¶

__ror__(self, other: object) → object¶

__rxor__(self, other: object) → object¶

__setstate__(self, state: int) → None¶

__xor__(self, other: object) → object¶

property name : str¶

class RobotStateType(self, value: int)¶

Bases: pybind11_object

Robot control frames.

Values:

REFERENCE_FRAME: Corresponds to a fixed reference frame attached to the robot structure.
ARTICULAR_FRAME: Corresponds to the joint state. This value is deprecated. You should rather use vpRobot::JOINT_STATE .
JOINT_STATE: Corresponds to the joint state.
END_EFFECTOR_FRAME: Corresponds to robot end-effector frame.
CAMERA_FRAME: Corresponds to a frame attached to the camera mounted on the robot end-effector.
TOOL_FRAME: Corresponds to a frame attached to the tool (camera, gripper…) mounted on the robot end-effector. This value is equal to vpRobot::CAMERA_FRAME .
MIXT_FRAME: Corresponds to a “virtual” frame where translations are expressed in the reference frame, and rotations in the camera frame.

__and__(self, other: object) → object¶

__eq__(self, other: object) → bool¶

__ge__(self, other: object) → bool¶

__getstate__(self) → int¶

__gt__(self, other: object) → bool¶

__hash__(self) → int¶

__index__(self) → int¶

__init__(self, value: int)¶

__int__(self) → int¶

__invert__(self) → object¶

__le__(self, other: object) → bool¶

__lt__(self, other: object) → bool¶

__ne__(self, other: object) → bool¶

__or__(self, other: object) → object¶

__rand__(self, other: object) → object¶

__ror__(self, other: object) → object¶

__rxor__(self, other: object) → object¶

__setstate__(self, state: int) → None¶

__xor__(self, other: object) → object¶

property name : str¶

__init__(self: visp._visp.robot.RobotPololuPtu, device: str = /dev/ttyACM0, baudrate: int = 9600, verbose: bool = false)¶

Default constructor.

Parameters:

device: Name of the serial interface used for communication.
baudrate: Baudrate used for the serial communication. Note that this parameter is only used on Windows.
verbose: When true, enable verbose mode.

getAngularVelocityResolution(self) → float¶: Return the minimul angular velocity in rad/s that could be applied to move the motors. It corresponds to 1 pwm converted in rad/s.

getMaxRotationVelocity(self) → float¶

Get the maximal rotation velocity that can be sent to the robot during a velocity control.

Returns:: Maximum rotation velocity expressed in rad/s.

getMaxTranslationVelocity(self) → float¶

Get the maximal translation velocity that can be sent to the robot during a velocity control.

Returns:: Maximum translational velocity expressed in m/s.

getNDof(self) → int¶: Return robot degrees of freedom number.

getPosition(*args, **kwargs)¶

Overloaded function.

getPosition(self: visp._visp.robot.RobotPololuPtu, frame: visp._visp.robot.Robot.ControlFrameType, q: visp._visp.core.ColVector) -> None
getPosition(self: visp._visp.robot.Robot, frame: visp._visp.robot.Robot.ControlFrameType) -> visp._visp.core.ColVector

getPositioningVelocityPercentage(self) → float¶

Get the percentage of the maximum velocity applied to move the PTU in position.

Note

See setPositioningVelocityPercentage()

Returns:: Positioning velocity percentage in [0, 100.0]. The maximum positioning velocity is given vpRobot::getMaxRotationVelocity() .

getRobotState(self) → visp._visp.robot.Robot.RobotStateType¶

get_eJe(*args, **kwargs)¶

Overloaded function.

get_eJe(self: visp._visp.robot.RobotPololuPtu, eJe: visp._visp.core.Matrix) -> None

Get the robot jacobian expressed in the end-effector frame.

Warning

End-effector frame is not the embedded camera frame. It corresponds to the frame associated to the tilt axis (see also get_cMe).

Parameters:

eJe: Jacobian between end effector frame and end effector frame (on tilt axis).

get_eJe(self: visp._visp.robot.RobotPololuPtu, q: visp._visp.core.ColVector, eJe: visp._visp.core.Matrix) -> None

Get the robot jacobian expressed in the end-effector frame.

Warning

End-effector frame is not the embedded camera frame. It corresponds to the frame associated to the tilt axis (see also get_cMe).

Parameters:

q: Joint positions to consider [rad].
eJe: Jacobian between end effector frame and end effector frame (on tilt axis).

get_fJe(*args, **kwargs)¶

Overloaded function.

get_fJe(self: visp._visp.robot.RobotPololuPtu, fJe: visp._visp.core.Matrix) -> None

Get the robot jacobian expressed in the robot reference frame.

Parameters:

fJe: Jacobian between reference frame (or fix frame) and end effector frame (on tilt axis).

get_fJe(self: visp._visp.robot.RobotPololuPtu, q: visp._visp.core.ColVector, fJe: visp._visp.core.Matrix) -> None

Get the robot jacobian expressed in the robot reference frame.

Parameters:

q: Joint positions to consider [rad].
fJe: Jacobian between reference frame (or fix frame) and end effector frame (on tilt axis).

static saturateVelocities(v_in: visp._visp.core.ColVector, v_max: visp._visp.core.ColVector, verbose: bool = false) → visp._visp.core.ColVector¶

Saturate velocities.

The code below shows how to use this static method in order to saturate a velocity skew vector.

#include <iostream>

#include <visp3/robot/vpRobot.h>

int main()
{
  // Set a velocity skew vector
  vpColVector v(6);
  v[0] = 0.1;               // vx in m/s
  v[1] = 0.2;               // vy
  v[2] = 0.3;               // vz
  v[3] = vpMath::rad(10);   // wx in rad/s
  v[4] = vpMath::rad(-10);  // wy
  v[5] = vpMath::rad(20);   // wz

  // Set the maximal allowed velocities
  vpColVector v_max(6);
  for (int i=0; i<3; i++)
    v_max[i] = 0.3;             // in translation (m/s)
  for (int i=3; i<6; i++)
    v_max[i] = vpMath::rad(10); // in rotation (rad/s)

  // Compute the saturated velocity skew vector
  vpColVector v_sat = vpRobot::saturateVelocities(v, v_max, true);

  std::cout << "v    : " << v.t() << std::endl;
  std::cout << "v max: " << v_max.t() << std::endl;
  std::cout << "v sat: " << v_sat.t() << std::endl;

  return 0;
}

Parameters:

v_in: visp._visp.core.ColVector¶: Vector of input velocities to saturate. Translation velocities should be expressed in m/s while rotation velocities in rad/s.
v_max: visp._visp.core.ColVector¶: Vector of maximal allowed velocities. Maximal translation velocities should be expressed in m/s while maximal rotation velocities in rad/s.
verbose: bool = false¶: Print a message indicating which axis causes the saturation.

Returns:

Saturated velocities.

setMaxRotationVelocity(self, maxVr: float) → None¶: Set the maximal rotation velocity that can be sent to the robot during a velocity control.

setMaxTranslationVelocity(self, maxVt: float) → None¶: Set the maximal translation velocity that can be sent to the robot during a velocity control.

setPosition(self, frame: visp._visp.robot.Robot.ControlFrameType, q: visp._visp.core.ColVector) → None¶

setPositioningVelocityPercentage(self, positioning_velocity_percentage: float) → None¶

Set the percentage of the maximum velocity applied to move the PTU in position.

Note

See getPositioningVelocityPercentage()

Parameters:

positioning_velocity_percentage: float¶: Percentage between [0,100] of the maximum velocity. The maximum positioning velocity is given vpRobot::getMaxRotationVelocity() .

setRobotState(*args, **kwargs)¶

Overloaded function.

setRobotState(self: visp._visp.robot.RobotPololuPtu, newState: visp._visp.robot.Robot.RobotStateType) -> visp._visp.robot.Robot.RobotStateType
setRobotState(self: visp._visp.robot.Robot, newState: visp._visp.robot.Robot.RobotStateType) -> visp._visp.robot.Robot.RobotStateType

setVelocity(self, frame: visp._visp.robot.Robot.ControlFrameType, q_dot: visp._visp.core.ColVector) → None¶

setVerbose(*args, **kwargs)¶

Overloaded function.

setVerbose(self: visp._visp.robot.RobotPololuPtu, verbose: bool) -> None

Enable/disable verbose mode.

Parameters:

verbose: Set to true to enable verbose mode, false otherwise.

setVerbose(self: visp._visp.robot.Robot, verbose: bool) -> None

stopVelocity(self) → None¶: Stop the velocity command.