Dissecting someone elses Matlab code

Recently I've tried to dissect this code http://benjamin-goldberg.com/Robot_Arm_Inverse_Kinematics.m

But to no avail, however, I will tell you what I know and what I want to know:

a. This code attempts to have the end of the 'arm' reach (0,0) b. The angles between each link is limited, hence why when Theta# is changed, it will sometimes not reach (0,0) (I think?) c. Arm lengths are changed in lines 11 and 13, Axis located at 42 d. He's working in radians e. Lines 14 - 16 allows the free motion of the links of the arms

That's pretty much all I know so far, things I would like to know are:

Pretty much what is happening in that For-Loop.

These are some things I want to do to the code after I've understood it:

Change the angle limitations

Lose the arm trail (But display the 'hand' trail)

Put this in a GUI so that it will follow my mouse constantly until I click it. It'll be impossible for it to reach some places (it'll only reach a distance of 3 units from the centre, hence a circle), so instead, it'll keep following it the best it can whilst fully intact.

All help very much appreciated, thanks!

Answer 1

[per isakson]

Are you posing this question to experts of robot arm kinematics? Do you have a problem using the tools of Matlab?

Did you ask Goldberg? He writes: "If you have any questions, please don’t hesitate to email me at ***."

Edit [13 May 2012, 11:32 BST - OK] Erased email.

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There are a few videos on youtube, which address debugging in Matlab. (There should be demos/videos, which focus on debugging, on The Mathworks website, but I fail to find one now.) See e.g. Matlab Debugger tutorial, Part A. and MATLAB Tutorial: Debugger to walk through code. The latter is presented by Doug Hull of The Mathworks. He has a blog with hundreds of videos on The Mathworks website. If you are not comfortable with the debugging tools you might want to watch a couple of videos.

What I would have done

1. make sure the Command Window and the Editor are docked in the Desktop, i.e. visible simultaneously.
2. turn the code into a function, i.e add the line "function a_good_name()" at the top of the code and "end" at the end. Save the function.
3. start explore the code

[Aaron]

Erm, I guess. I'm just not 100% familiar with Matlab yet, but this is a start to my attempts to one of my Uni assignments.

[Aaron]

I've just emailed him, however, he did submit his code almost 2 years ago. Hope he responds.