Plot Frame

RTSX Help: Plot frames in a transformation chain

PlotFrame

PlotFrame( ) provides a more systematic way to visualize a sequence of homogeneous transformations than trplot( ). A tranformation chain must be passed to the function instead of a homogeneous transformation matrix.

Syntax

  • PlotFrame(fc, options)

Input Arguments

  • fc  — a chain of completed coordinate frames created by SerialFrame( )

Output Arguments

  • none

Options

Note : options in [ ] must be passed to the function in pairs.

  • ‘grid’ — show grid
  • ‘oinfo’ — show origin location (could look messy when several frames are condensed together)
  • [ ‘figure’, fnum] — command the plot to a particular window indicated by fnum

Description

To study robot kinematics, one must understand clearly the basic of kinematic chain connecting coordinate frames together. PlotFrame( ) serves as a convenient graphical tool to visualize such a chain. The function accepts a completed chain created by SerialFrame( ) . An incomplete chain must be resolved first by ResolveFrame( ), if possible. Unlike trplot( ) where a user has control over a frame’s axis color and line style, PlotFrame( ) assigns colors to frames automatically depending on their positions in the chain.

Examples

The example below shows the necessary steps from frame creation to plotting. The result is shown in Figure 1 below.

// first create a sequence of frames
clear F;
F(1)=Frame(eye(4,4),'name','U');  
F(2)=Frame(trotx(pi/2)*transl([0 1 1]),'name','V'); 
F(3)=Frame(trotz(pi/4)*transl([2 3 -1]),'name','W');  
F(4)=Frame(troty(pi/3),'name','Y');  
fc=SerialFrame(F,'name','Chain 1');
PlotFrame(fc);


Figure 1: transformation chain plot example with PlotFrame( )

See Also