Automating Manufacturing Systems - Process Control and ...

continuous actuators - 24.23
e f
= r f
i f
+ l f
i f
D
T
=
K T
i f
T
-- = JD 2 + BD
θ
--
θ
T
θ
--
i f
1
= -----------------------
JD 2 + BD
K T
θ
= -- --
T = -----------------------
Ti f JD 2 + BD
K T
θ θ
--- -- i f
---
e f
i f
e f
T
---
T
--
⎛ ⎞ 1
-----------------------
i
JD 2 ⎟ ⎜
----------------- ⎛ ⎞
= =
+ BD ⎝ ⎠ r f
+ l f
D ⎝ ⎠
f
--- ⎞ ⎛ 1
= = K
e f
i f
e T
-----------------
f
r f
+ l f
D
⎝
⎠
Figure 24.20
Equations for a controlled field motor
24.3 HYDRAULICS
Hydraulic systems are used in applications requiring a large amount of force and
slow speeds. When used for continuous actuation they are mainly used with position feedback.
An example system is shown in Figure 24.21. The controller examines the position
of the hydraulic system, and drivers a servo valve. This controls the flow of fluid to the
actuator. The remainder of the provides the hydraulic power to drive the system.