Robotic toolbox 'link' command outputs 5 values, not 4

Hi all

I am trying to create a robot link:

 A= Link ([0 0 0 0], 'modified')
A = 
 theta=q, d=          0, a=          0, alpha=          0, offset=          0 (R,modDH)

Why when inputting 4 0's I get 5 values back. My rotational link has only 1 variable theta and I thought d is the link offset. Also, if I didn't define the fifth variable why is the system creating it. In all the tutorials people get 4 values back according to DH parameters Please help and thanks for your time Regards Timur

Answer 1

[Zhankui Peng]

• Column Symbol Description
• 1 alphai link twist angle
• 2 Ai link length
• 3 sitai link rotation angle
• 4 Di link offset distance
• 5 sigmai joint type; 0 for revolute, non-zero for prismatic