Robot2hAT

RTSX Help: Compute sequence of homogeneous matrices from robot model

Robot2hAT

From a robot model and a sequence of joint variable values, compute homogeneous transformation matrices from each frame to base.

Syntax

  • [A,T] = Robot2hAT(robot,qs)

Input Arguments

    • robot –a robot model
    • q –a ns x nq matrix of joint variable values, where ns = number of setpoints (move steps) and nq = number of joint variables

    Output Arguments

    • A — a 4 x 4 x ns x (nq+2) homogeneous transformation hyper-matrix representing each frame w.r.t. frame below, where ns = number of setpoints (move steps) and nq = number of joint variables
    • T — a 4×4 x ns x (nq+2) homogeneous transformation matrix representing each frame w.r.t base

    Description

    Robot2hAT( ) can be thought of as an extension of Link2AT( ) to handle a sequence of joint variable values. The output matrices are now 4-dimensional. Another difference is Robot2hAT( ) accepts a robot model as input argument and takes into account the base and tool frame of the robot.

    Frankly, Robot2hAT( ) is designed to support animation functions and is somewhat too complicated for direct use. To solve a standard forward kinematics problem with a single set of joint variables, FKine( ) or Link2AT( ) suffices.

    Examples

    The following example shows how to compute hyper-matrices A and T from a two-link manipulater with a sequence of joint vairables.

    clear L;
    a1 = 1.2; a2 = 1;
    L(1)=Link([0 0 a1 0]);
    L(2)=Link([0 0 a2 0]);
    twolink=SerialLink(L);  // a 2-link manipulator
    // generate simple setpoints
    // both joints move full circle
    t = [0:0.01:1]';        // "time" data
    qs = [2*pi*t 2*pi*t];  
    [A,T]=Robot2hAT(twolink, qs);

    See Also

    • Link2AT — Compute homogenous matrices from link data
    • FKine — Compute forward kinematics from robot model