updating comments on leg matrix t01 to show differences between origi…

[MZandtheRaspberryPi]

Thanks for going through the paper and finding the discrepancies with matrix t01 and t12. It helped me a lot as I was looking through this. I found one typo I think in the comments of your code, where the paper t01 matrix i see here https://www.ijstr.org/final-print/sep2017/Inverse-Kinematic-Analysis-Of-A-Quadruped-Robot.pdf in row index 1 col index 1 has positive cos(theta1).

The matrix in the paper still has weird stuff going on in the row index 2. I only threw this PR out as the comments confused me slightly as I was comparing the matrices in your comments to the paper.

I agree with you, and did out the matrix math using their DH parameters and arrive at the same thing you got.
https://wikimedia.org/api/rest_v1/media/math/render/svg/6963d0c47a3a894ff0719c8df348d188b996074e

joint i	theta i (degree)	alpha i (degree)	r i (meters)	d i (meters)
0-1	theta1	0	l1	0

Looking at t01:

cos(theta1)	-sin(theta1)*cos(0)	sin(theta1) * sin(0)	-l1 * cos(theta1)
sin(theta1)	cos(theta1) * cos(0)	-cos(theta1) * sin(0)	-l1 * sin(theta1)
0	sin(0)	cos(0)	0
0	0	0	1

so that is:

cos(theta1)	-sin(theta1)* 1	sin(theta1) * 0	-l1 * cos(theta1)
sin(theta1)	cos(theta1) * 1	-cos(theta1) * 0	-l1 * sin(theta1)
0	0	1	0
0	0	0	1

so that is:

cos(theta1)	-sin(theta1)	0	-l1 * cos(theta1)
sin(theta1)	cos(theta1)	0	-l1 * sin(theta1)
0	0	1	0
0	0	0	1

I did the same thing for matrix t12, and also got something that agrees with you, just with a different sign on the 1 in row index 2. This is probably do to spot micro doing legs pointing back, and alpha being positive pi/2 instead of -pi/2 as in the paper model.