This thesis presents the design of various closed-loop real-time control of a novel
linear magnetostrictive actuator. The novel linear magnetostrictive actuator which uses
Terfenol-D as the magnetostrictive material was developed by Sadighi. It solves the
problem of power consumption in a conventional magnetostrictive actuator. However,
the control system of this magnetostrictive actuator cannot control the current in the coils,
which limits the performances of the real-time position control. In the closed-loop
real-time control system proposed in this thesis, the controller is designed depending on
the change of current.
The closed-loop real-time control design focused on the position control of the
active element in the novel linear magnetostrictive actuator. The closed-loop
position-control system of the linear magnetostrictive actuator was successfully designed
by implementing a closed-loop current-control system as an inner loop of the entire
control system. This design offers the flexibility to design various position controllers in
the closed-loop position-control system.
The closed-loop current-control design uses pulse-width modulation (PWM)
signal to change the current in the coils of the novel linear magnetostrictive actuator. By
changing the duty ratio of the PWM signal, the current in the coils can be changed from
zero to its maximum value. With a current controller using an integrator with a gain of
10, the current can be controlled with high response time and an error of /- 0.01 A.
The position-controller design was successfully conducted by using four different
approaches. First, a proportional-integral-derivative (PID) controller which was designed
by relay-auto tuning method with experiments exhibited a position error of ±1 μm with a
5 μm peak-to-peak position noise. Second, a PID controller which was designed by
root-locus can control the position with a position error of /- 3-4 μm with a 5 μm
peak-to-peak position noise. Third, a linear variable velocity controller exhibited a
position error of /-5 μm with a 5 mu m peak-to-peak position noise. Then, the sliding mode
control (SMC) exhibited a position error of /-5 μm with a 5 μm peak-to-peak position
noise.
| Identifer | oai:union.ndltd.org:tamu.edu/oai:repository.tamu.edu:1969.1/ETD-TAMU-2010-08-8470 |
| Date | 2010 August 1900 |
| Creators | Chen, Chien-Fan |
| Contributors | Kim, Won-jong |
| Source Sets | Texas A and M University |
| Language | en_US |
| Detected Language | English |
| Type | Book, Thesis, Electronic Thesis, text |
| Format | application/pdf |
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