Four-quadrant current-regulated DC servo drive using a fuzzy logic-based controller
DC servo drives normally employ an internal current loop as well as a speed control loop requiring the use of a speed transducer. This paper presents a fuzzy logic controlled DC servo drive without the need for mechanical speed sensors. Speed estimation is performed from measurements of the input current and voltage to the motor. The latter is driven by a current-regulated voltage source DC-DC converter capable of operating in all four quadrants of the torque-speed plane. The fuzzy controller uses the calculated rotor speed to produce the armature current command necessary for matching the reference speed profile. The proposed system is shown to track the dynamic input speed settings and to reject step load disturbances with largely reduced settling times and steady state errors.
We experimentally stabilize a chaotic output of a diode-laser-pumped Nd:yttrium–aluminum–garnet laser by using oscillation quenching. When the chaotic laser is mutually coupled with a Rossler oscillator that is implemented by an electronic circuit, both chaotic systems are stabilized to steady states. We experimentally study the route to the steady states as the coupling strength increases, and numerically confirm the route by coupling Lorenz and Rossler oscillators mutually.