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Simple And Robust Method for Near-Minimum-Time Control of Electro Mechanical Actuators

IP.com Disclosure Number: IPCOM000101453D
Original Publication Date: 1990-Aug-01
Included in the Prior Art Database: 2005-Mar-16
Document File: 3 page(s) / 65K

Publishing Venue

IBM

Related People

Wong, D: AUTHOR [+2]

Abstract

Disclosed is a method to achieve the near minimum time control of electromechanical actuators. The method described is insensitive to system parameter variations and external load disturbances. In addition, it is simple to program in real time and enhances the accuracy of the actuator movements.

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This is the abbreviated version, containing approximately 78% of the total text.

Simple And Robust Method for Near-Minimum-Time Control of Electro Mechanical Actuators

       Disclosed is a method to achieve the near minimum time
control of electromechanical actuators.  The method described is
insensitive to system parameter variations and external load
disturbances.  In addition, it is simple to program in real time and
enhances the accuracy of the actuator movements.

      A control system including current feedback loop can reduce the
complexity of computation of the two switching times of
electromechanical actuators.  Simplified as a second-order system,
i.e., X(s)/ Ic(s) = Kt/s(M s + B), this method controls the actuator
to achieve minimum-time performance.  Assuming that there are no
viscous friction or load disturbances, switching time t1 is the time
required for the actuator to travel the first half of the desired
displacement (xf/2).  In other words, the actuator accelerates over
the first xf/2 and decelerates over the second xf/2 using rated
current.  The total traveling time is 2t1.  The velocity profile
(position increments) of the second half should be the mirror image
of the first half with respect to t1.  Thus, this simple and robust
controller applies the maximum calculated current to the actuators
and stores the position increments during the first xf/2 of travel.
In the second xf/2, the controller will compute the current command
according to the stored position increments using PD
(Proportional-plus-Derivative) or PI...