Robot manipulators (arms)

A robot manipulator is an object of a subclass of Robot, which provides the methods in the tables below. The subclass depends on how the robot is defined: from Denavit-Hartenberg parameters, from an elementary transform sequence, or from a URDF file. The robots that the Toolbox provides ready made are described under Models.

Construction

A robot is made in one of three ways, and each has its own class.

Robot	Robot manipulator defined by links or an elementary transform sequence
URDFRobot	Base class for robot models loaded from a URDF or xacro file.
DHRobot	Class for robots defined using Denavit-Hartenberg notation

A Robot is made from an elementary transform sequence, and can be a tree. (ERobot is a subclass with the same behaviour, kept for compatibility.) A URDFRobot is made from a URDF or xacro file. A DHRobot is made from a list of links, each with its Denavit-Hartenberg parameters, standard or modified, and a prismatic or revolute joint, using the link classes below.

RevoluteDH	Class for revolute links using standard DH convention.
PrismaticDH	Class for prismatic link using standard DH convention.
RevoluteMDH	Class for revolute links using modified DH convention.
PrismaticMDH	Class for prismatic link using modified DH convention.

>>> import roboticstoolbox as rtb
>>> from roboticstoolbox import DHRobot, Robot, RevoluteDH, ET
>>> dh = DHRobot([RevoluteDH(a=1), RevoluteDH(a=1)], name="two link")  # from DH parameters
>>> e = ET.Rz() * ET.tx(1) * ET.Rz() * ET.tx(1)
>>> ets = Robot(e, name="two link")  # from an elementary transform sequence
>>> dh.n, ets.n
(2, 2)

copy	Make a copy of the robot
addconfiguration	Add a named joint configuration

Information

name	Get/set robot name
manufacturer	Get/set robot manufacturer's name
comment	Get/set robot comment
keywords	Keywords that describe the robot
n	Number of joints
nlinks	Number of links
nbranches	Number of branches
links	Robot links
structure	Return the joint structure string
isrevolute	Check if joint is revolute
isprismatic	Check if joint is prismatic
revolutejoints	Revolute joints as bool array
prismaticjoints	Prismatic joints as bool array
q	Get/set robot joint configuration
qd	Get/set robot joint velocity
qdd	Get/set robot joint acceleration
qlim	Joint limits
random_q	Return a random joint configuration
configs	Named joint configurations
base	Get/set robot base transform
tool	Get/set robot tool transform
gravity	Get/set default gravitational acceleration
reach	Reach of the robot
hasgeometry	Robot has geometry model
hascollision	Robot has collision model
hasdynamics	Robot has dynamic parameters

Visualization

plot	Graphical display and animation
teach	Graphical teach pendant
plot_vellipse	Plot the velocity ellipsoid for a manipulator.
plot_fellipse	Plot the force ellipsoid for a manipulator.
vellipse	Create a velocity ellipsoid object for plotting with PyPlot.
fellipse	Create a force ellipsoid object for plotting with PyPlot.
showgraph	Display a link transform graph in browser
default_backend	Get default graphical backend
set_default_backend	Set the default graphical backend for all robots

The graphical backends do the drawing.

Kinematics

fkine	Forward kinematics
fkine_all	Compute the pose of every link frame
jacob0	Manipulator geometric Jacobian in the start frame
jacobe	Manipulator geometric Jacobian in the end-effector frame
jacob0_analytical	Manipulator analytical Jacobian in the start frame
jacob0_dot	Time derivative of manipulator Jacobian in frame {0}
hessian0	Manipulator Hessian in the start frame
hessiane	Manipulator Hessian in the end-effector frame
manipulability	Manipulability measure
jacobm	The manipulability Jacobian
jtraj	Joint-space trajectory between two joint configurations
ikine_LM	Levenberg-Marquardt Numerical Inverse Kinematics Solver
ik_LM	Fast Levenberg-Marquardt Numerical Inverse Kinematics Solver

ikine_LM and ik_LM are two examples: the first is written in Python, the second in C++ and is faster but has limits. All the inverse kinematics methods, ikine_XX and ik_XX, are described under Inverse Kinematics.

Dynamics

rne	Compute inverse dynamics via recursive Newton-Euler formulation
gravload	Compute gravity load
inertia	Manipulator inertia matrix
coriolis	Coriolis and centripetal term
accel	Compute acceleration due to applied torque
fdyn	Integrate forward dynamics
itorque	Inertia torque
friction	Manipulator joint friction
nofriction	Remove manipulator joint friction
payload	Add a payload to the end-effector
payload_capacity	Compute the payload capacity of the manipulator
perturb	Perturb robot parameters

Collision checking

iscollided	Check if the robot is in collision with a shape
closest_point	Find the closest point between robot and shape

The Shape that these methods take is a class of the spatialgeometry package, such as Sphere, Cuboid or Mesh. In the signatures it links to the documentation of that package.