FKine

RTSX Help: Compute forward kinematics from robot model

FKine

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

Syntax

  • T=FKine(robot,q)

Input Arguments

  • robot –a robot model
  • q –a 1 x nq vector of joint variable values, where nq = number of joint variables

Output Arguments

  • T — a 4×4 homogeneous transformation matrix representing tool frame w.r.t base

Description

A normal forward kinematics solution refers to a homogeneous transformation from the tool frame to base frame. FKine( ) simply calls Link2AT( ), extracts the transformation from top to bottom link, and then adjust for the base and tool frames of the robot. The return matrix is just a 4 x 4 homogenous transformation matrix from tool to base. Nothing else matters.

Examples

Goal: find forward kinematics from tool to base of an RRR robot.

-->clear L;
 -->d1 = 1; a2 = 1; a3 = 1;
 -->L(1)= Link([0 d1 0 pi/2]);
 -->L(2)=Link([0 0 a2 0]);    
 -->L(3)=Link([0 0 a3 0]);
 -->RRR_robot=SerialLink(L);
 -->q0 = [0 0 0];
 -->T=FKine(RRR_robot,q0)
 T  =
    1.    0.    0.    2.  
    0.    0.  - 1.    0.  
    0.    1.    0.    1.  
    0.    0.    0.    1.

See Also

  • Link2AT — Compute homogenous matrices from link data
  • Robot2hAT — Compute sequence of homogeneous matrices from robot model