getTransform

Get transform between body frames

Syntax

transform = getTransform(robot,configuration,bodyname)

transform = getTransform(robot,configuration,sourcebody,targetbody)

Description

transform = getTransform(robot,configuration,bodyname) computes the transform that converts points in the bodyname frame to the robot base frame, using the specified robot configuration.

transform = getTransform(robot,configuration,sourcebody,targetbody) computes the transform that converts points from the source body frame to the target body frame, using the specified robot configuration.

Examples

Get Transform Between Frames for Robot Configuration

Get the transform between two frames for a specific robot configuration.

Load a sample robots that include the puma1 robot.

load exampleRobots.mat

Get the transform between the 'L2' and 'L6' bodies of the puma1 robot given a specific configuration. The transform converts points in 'L6' frame to the 'L2' frame.

transform = getTransform(puma1,randomConfiguration(puma1),'L2','L6')

transform = 4×4

    0.2295   -0.4122    0.8817    0.0485
    0.8621   -0.3344   -0.3807    0.2118
    0.4517    0.8475    0.2786   -0.4027
         0         0         0    1.0000

Input Arguments

robot — Robot model

rigidBodyTree object

Robot model, specified as a rigidBodyTree object.

configuration — Robot configuration

structure array

Robot configuration, specified as a structure array with joint names and positions for all the bodies in the robot model. You can generate a configuration using homeConfiguration(robot), randomConfiguration(robot), or by specifying your own joint names and positions in a structure array.

bodyname — Body name

string scalar | character vector

Body name, specified as a string scalar or character vector. This body must be on the robot model specified in robot.

Data Types: char | string

targetbody — Target body name

string scalar | character vector

Target body name, specified as a character vector. This body must be on the robot model specified in robot. The target frame is the coordinate system you want to transform points into.

Data Types: char | string

sourcebody — Body name

string scalar | character vector

Body name, specified as a string scalar or character vector. This body must be on the robot model specified in robot. The source frame is the coordinate system you want points transformed from.

Data Types: char | string

Output Arguments

transform — Homogeneous transform

4-by-4 matrix

Homogeneous transform, returned as a 4-by-4 matrix.

Extended Capabilities

C/C++ Code Generation

Generate C and C++ code using MATLAB® Coder™.

Usage notes and limitations:

When creating the rigidBodyTree object, use the syntax that specifies the MaxNumBodies as an upper bound for adding bodies to the robot model. You must also specify the DataFormat property as a name-value pair. For example:

robot = rigidBodyTree("MaxNumBodies",15,"DataFormat","row")

To minimize data usage, limit the upper bound to a number close to the expected number of bodies in the model. All data formats are supported for code generation. To use the dynamics functions, the data format must be set to "row" or "column".

The show and showdetails functions do not support code generation.