Harmonic Drive FHA Mini Series, Руководство пользователя

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Chapter 1 Overview of the FHA-C mini series
FHA-C mini
16
1-9-2 Torsional stiffness
When a torque is applied to the output flange of the actuator with the motor locked, the resulting torsional
wind up is near proportional to the torque.
The upper right figure shows the torsional stiffness
characteristics of the output flange applying torque starting
from zero to plus side [+T
0
] and minus side [–T
0
]
.
This
trajectory is called torque-torsion characteristics which
typically follows a loop 0
→ A → B → A’ → B’ → A as illustrated.
The torsional stiffness of the FHA-C mini actuator is
expressed by the slope of the curve that is a spring rate
(wind-up)
(unit: N
･ m/rad).
The torsional stiffness may be evaluated by dividing torque-
torsion characteristics curve into three major regions. The
spring rate of each region is expressed K
1,
K
2,
and K
3
respectively.
K
1
: spring rate for torque region 0-T
1
K
2
: spring rate for torque region T
1
-T
2
K
3
: spring rate for torque region over T
2
The wind-up for each region is expressed as follows:
◆ wind-up for torque region 0-T
1:
θ
1
T < T
1
◆
wind-up for torque region T
1
-T
2:
θ
2
=
θ
1
T
1
< T < T
2
◆
wind-up for torque region over T
2:
θ
3
=
θ
2
θ
: Wind up
T
2
< T
The table below shows T
1
-T
3
, K
1
-K
3
, and
θ
1
-
θ
2
values of each actuator.
Model FHA-8C FHA-11C FHA-14C
Reduction ratio 1:30 1:50 1:100 1:30 1:50 1:100 1:30 1:50 1:100
T
1
N
･
m
0.29 0.29 0.29 0.80 0.80 0.80 2.0 2.0 2.0
kgf ･ m
0.030 0.030 0.030 0.082 0.082 0.082 0.20 0.20 0.2
K
1
x10
4
N
･
m/rad
0.034 0.044 0.091 0.084 0.22 0.27 0.19 0.34 0.47
kgf
･
m/arc min
0.010 0.013 0.027 0.025 0.066 0.080 0.056 0.10 0.14
θ
1
x10
-4
rad 8.5 6.6 3.2 9.5 3.6 3.0 10.5 5.8 4.1
arc min 3.0 2.3 1.1 3.3 1.2 1.0 3.6 2.0 1.4
T
2
N
･
m
0.75 0.75 0.75 2.0 2.0 2.0 6.9 6.9 6.9
kgf
･
m
0.077 0.077 0.077 0.20 0.20 0.20 0.70 0.70 0.7
K
2
x10
4
N
･
m/rad 0.044 0.067 0.10 0.13 0.30 0.34 0.24 0.47 0.61
kgf ･ m/arc min
0.013 0.020 0.031 0.037 0.090 0.10 0.07 0.14 0.18
θ
2
x10
-4
rad 19 13 8 19 8 6 31 16 12
arc min 6.6 4.7 2.6 6.5 2.6 2.2 10.7 5.6 4.2
K
3
x10
4
N ･ m/rad
0.054 0.084 0.12 0.16 0.32 0.44 0.34 0.57 0.71
kgf ･ m/arc min
0.016 0.025 0.036 0.047 0.096 0.13 0.10 0.17 0.21
The table below shows torque-wind-up relation for reference. （ unit: N ･ m ）
Model FHA-8C FHA-11C FHA-14C
Reduction ratio 1:30 1:50 1:100 1:30 1:50 1:100 1:30 1:50 1:100
2 0.20 0.25 0.56 0.49 1.3 1.8 1.1 2.0 3.0
4 0.42 0.63 1.2 1.1 3.3 4.2 2.3 4.7 6.5
6 0.68 1.1 1.9 1.8 5.2 6.8 3.6 7.6 11
1
K
T
= 
+
T – T
1
K
2
+
T – T
2
K
3
B