trchain

Chain 3D transforms from string

T = trchain(s, q) is a homogeneous transform (4x4) that results from compounding a number of elementary transformations defined by the string s. The string s comprises a number of tokens of the form X(ARG) where X is one of Tx, Ty, Tz, Rx, Ry, or Rz. ARG is the name of a variable in MATLAB workspace or qJ where J is an integer in the range 1 to N that selects the variable from the Jth column of the vector q (1xN).

For example:

trchain('Rx(q1)Tx(a1)Ry(q2)Ty(a3)Rz(q3)', [1 2 3])

is equivalent to computing:

trotx(1) * transl(a1,0,0) * troty(2) * transl(0,a3,0) * trotz(3)

Notes

• The string can contain spaces between elements or on either side of ARG.
• Works for symbolic variables in the workspace and/or passed in via the vector Q.
• For symbolic operations that involve use of the value pi, make sure you define it first in the workspace: pi = sym('pi');

See also

trchain2, trotx, troty, trotz, transl, SerialLink.trchain, ets

Robotics Toolbox for MATLAB © 1990-2014 Peter Corke.