User manual

Barrett Technology, Inc.
BA4-310 System User Manual Version 1.1
69
Appendix B - Motor-to-Joint Position Transformations
The following transformations show the change in joint positions as a function of motor
positions. The input transmission ratios and the differential transmission ratios are calculated
from known pulley, pinion, and cable diameters.






































−−
−
−
=














3
2
1
0
4
2
3
2
3
22
1
4
3
2
1
1
000
0
22
0
0
2
1
2
1
0
000
1
θ
θ
θ
θ
θ
θ
θ
θ
M
M
M
M
N
N
n
N
n
NN
N
J
J
J
J
Equation 3:
Arm Motor-to-Joint position transformations
















=
















77.17
68.1
21.28
87.35
2
4
3
3
2
1
N
N
n
N
N
N
Equation 4:
Arm transmission ratios




























−
−
=










6
5
4
7
5
6
5
6
55
7
6
5
1
00
0
22
0
2
1
2
1
θ
θ
θ
θ
θ
θ
M
M
M
N
N
n
N
n
NN
J
J
J
Equation 5:
Wrist Motor-to-Joint position transformations