Main Content

getTransform

Get transform between body frames

collapse all in page

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.

example

Examples

collapse all

Open Live Script

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

Load a Yaskawa Motoman MH-5 manipulator from the Robotics System Toolbox™ loadrobot.

motoman = loadrobot("yaskawaMotomanMH5");
showdetails(motoman)
--------------------
Robot: (6 bodies)

 Idx     Body Name     Joint Name     Joint Type     Parent Name(Idx)   Children Name(s)
 ---     ---------     ----------     ----------     ----------------   ----------------
   1        link_s        joint_s       revolute         base_link(0)   link_l(2)  
   2        link_l        joint_l       revolute            link_s(1)   link_u(3)  
   3        link_u        joint_u       revolute            link_l(2)   link_r(4)  
   4        link_r        joint_r       revolute            link_u(3)   link_b(5)  
   5        link_b        joint_b       revolute            link_r(4)   link_t(6)  
   6        link_t        joint_t       revolute            link_b(5)   
--------------------

Get the transform between the "link_l" and "link_t" bodies of the motoman robot given a specific configuration. The transform converts points in "link_l" frame to the "link_t" frame. 

q = randomConfiguration(motoman);
show(motoman,q);

Figure contains an axes object. The axes object with xlabel X, ylabel Y contains 20 objects of type patch, line. These objects represent base_link, link_s, link_l, link_u, link_r, link_b, link_t, link_s_mesh, link_l_mesh, link_u_mesh, link_r_mesh, link_b_mesh, link_t_mesh, base_link_mesh.

transform = getTransform(motoman,q,"link_l","link_t")
transform = 4×4

    0.7787    0.0961   -0.6199    0.3115
    0.5256    0.4396    0.7283   -0.4624
    0.3425   -0.8930    0.2918   -0.1886
         0         0         0    1.0000

Input Arguments

collapse all

Robot model, specified as a rigidBodyTree object.

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.

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

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

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

collapse all

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

Extended Capabilities

Version History

Introduced in R2016b

expand all

See Also

| | | |