Rotational speed

About: Rotational speed is a research topic. Over the lifetime, 23327 publications have been published within this topic receiving 151696 citations. The topic is also known as: speed of revolution & revolution rate.

Nonlinear speed observer for high-performance induction motor control

Abstract: In this paper, we consider the problem of estimating the angular velocity of an induction motor using encoder measurements. Two methods are compared. In the first method, the speed is found by calculating the backward difference of the position measurement and low-pass filtering the result. In the second method, the velocity is estimated using a nonlinear observer constructed using the known dynamic model of the induction motor. The performance of the two methods is evaluated in the context of their use for velocity feedback in a high-performance field-oriented control law. Experimental results demonstrate that the speed observer leads to a smoother operation of the motor in closed-loop. With the estimator based on differentiation, either the delay imposed by the low-pass filter is too large to maintain high bandwidth feedback, or the fluctuations in the estimated speed are so large that much more energy ends up being dissipated to achieve the same control task. >

Control motor integrated with a direct current motor and a speed control circuit

Abstract: A control motor comprising an integrated direct current motor and speed control circuit, the speed control circuit controlling a rotational speed of the direct current motor by means of changing a voltage applied to an armature by a chopping of a switching element, the speed control circuit being composed upon a printed circuit board, the printed circuit board being supported in the direct current motor by a case member formed of a heat-conducting material, and a radiation portion of the switching element which is closely contracted with a projection formed integrally with the case member and is installed in the projection.

Speed control circuit for an electric power tool

Abstract: A method and apparatus for controlling the rotational speed of an electronically controlled power tool in both the forward and reverse direction When the reversing switch is placed in the reverse direction, the electronic speed control circuit automatically limits the speed of the motor to a predetermined maximum value The speed control circuit also is adapted to sense a change in the state of the reversing switch and remove power to the motor until it coasts down to a relatively slow speed or to zero before reapplying power in the opposite direction The speed control circuit monitors the rotational speed of the motor by means of a tachogenerator comprising a ring magnet mounted on the rearward end of the rotor shaft of the motor outboard of the commutator-end bearings and a Hall effect device mounted to the peripheral flange of a carrier which encircles the ring magnet so that the ring magnet and Hall effect device are separated by a small radially extending gap

Quad tilt rotor vertical take off and landing (vtol) unmanned aerial vehicle (uav) with 45 degree rotors

Abstract: A system and method to control the stability and direction of a quad tilt vertical takeoff and landing (VTOL) unmanned aerial vehicle (UAV) by manipulating the rotational speed of propellers at each rotor while simultaneously tilting the rotors in a 45 degree configuration related to a central axis for directional control. Each rotor is attached to a tilting mechanism configured to be symmetrically aligned at a 45 degree angle from a central axis to manipulate a directional angle of each rotor along a first and second axis. The first and fourth rotors are aligned on the first axis while the second and third rotors are aligned on the second axis. A controller includes a first control loop for manipulating the rotational speed of the propellers to control the aircraft balance and a second control loop for controlling lateral movement by tilting the rotors along the first and second axis.

Drive state shift control apparatus and method for vehicle

Abstract: A drive state shift control apparatus and method switches a hybrid drive (HEV) mode to an electric drive (EV) mode without engine stoppage shock or eliminates gearshifting shock in an electric vehicle In response to a decrease in accelerator opening APO, a request for fourth-to-fifth upshift is issued, then request for HEV-to-EV mode shift is issued At the time of the upshift, a direct clutch D/C is disengaged At a first time interval after the mode shift is issued, a first clutch is disengaged At a second time interval after the mode shift is issued, the engine begins to stop and the rotational speed of the motor-generator is controlled so that the speed falls to a predetermined rotational speed close to an after-gearshift rotational speed within a target shifting time interval When the rotational speed reaches the predetermined rotational speed, a front brake Fr/B is engaged to perform a fourth-to-fifth upshift, and the torque of the motor is controlled so as to engage the one-way clutch smoothly