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Angular displacement

About: Angular displacement is a research topic. Over the lifetime, 5102 publications have been published within this topic receiving 46081 citations. The topic is also known as: rotational displacement.


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Patent
17 Nov 2009
TL;DR: In this article, a sensorless control system for an electrical machine is provided comprising a rotor and a stator having one or more phase windings for generating a rotating stator magnetic field.
Abstract: The present invention relates to control of synchronous machines. A sensorless control system for an electrical machine is provided comprising a rotor and a stator having one or more phase windings for generating a rotating stator magnetic field. The current in the phase windings is monitored to determine real and imaginary components of the current vector in a rotating reference frame, from which real and imaginary components of the emf vector rotating in the rotating reference frame can also be determined. The ratio of the real and imaginary emf components is calculated, and an angular position of the rotational emf vector is estimated from this ratio. An angular error signal indicative of the deviation of the estimated angular position from a desired position in line with the real axis of the rotating reference frame is determined, and the machine is controlled such that the error signal tends towards zero.

38 citations

Patent
05 Jun 2001
TL;DR: In this paper, a rotatable arc segment magnet is arranged to rotate about the stationary components of the sensor, which include a pair of stationary flux concentrators, separated by a Hall probe.
Abstract: A linear output and non-contacting angular position sensor has a rotatable arc segment magnet arranged to rotate about the stationary components of the sensor, which include a pair of stationary flux concentrators, separated by a Hall probe; or, the magnet may be arranged to rotate at the center of the sensor with the stationary components fixed outside the magnet. With either arrangement, the Hall probe produces a direct 0 to 5 V d.c. output which varies linearly with the rotational angle of the magnet as the magnet rotates through a predetermined angle. The predetermined angle of rotation is generally equal to the arc formed by the flux concentrators and the arc of the magnet is generally 20-40% greater than the arc of the flux concentrators.

38 citations

Patent
20 Nov 1996
TL;DR: In this paper, a position and speed sensor comprising a circular element (1) rotatably driven about its axis is presented, and an electrical signal is produced by the sensor means (5) corresponding to the passage of each of the sensed position indicators (3, 4).
Abstract: A position and speed sensor comprising a circular element (1) rotatably driven about its axis. The circular element (1) has two position indicators (3, 4) of different angular width. A sensor means (5) is fixed in position with respect to and adjacent to the circular element (1). The sensor means (5) has a sensing element for sensing the passage of each of the position indicators (3, 4) past the sensing element. An electrical signal is produced by the sensor means (5) corresponding to the passage of each of the sensed position indicators (3, 4). The signal has a duration corresponding to the angular widths of the sensed position indicators (3, 4). Also included is a means to process the electrical signal to produce information as to the angular position and angular velocity of the circular element. A method for reverse rotation detection using the position and speed sensor means (5) is also disclosed.

38 citations

Patent
23 May 1977
TL;DR: In this article, an optical radar is disclosed in which fine vernier range and angular displacement accuracy is achieved by projecting a burst of coherent pulses so as to strobe a target passing through the field of view of the projection apparatus.
Abstract: An optical radar is disclosed in which fine vernier range and angular displacement accuracy is achieved by projecting a burst of coherent pulses so as to strobe a target passing through the field of view of the projection apparatus. The use of the pulse burst permits the most recent information to be utilized in obtaining the target track. Prior to projection, the pulses in the burst are sampled. The resulting signal is delayed by an amount corresponding to course range and is directed down one of a pair of oppositely directed delay lines. The signals returned from the target are detected by a sectorized receiver, with an electrical output signal from a detector in one of the sectors being applied to the other delay line in the corresponding pair, such that the signal corresponding to the returned pulse propagates in a direction opposite to that of the sampled signal corresponding to the transmitted pulse. The delay lines are tapped at various points corresponding to vernier range and each pair of taps is coupled to a device which ascertains the coincidence of counter-propagating pulses, thereby to establish the vernier range of the target from the projection apparatus. Angular displacement from boresight is measured as a function of the sector occupied by the target, with the number of pairs of oppositely directed delay lines corresponding to the number of sectors in the receiving apparatus. In one embodiment, a waterfall type display is used which displays angular displacement versus vernier range such that an accurate target track may be obtained. The receiving apparatus may be provided with zoom optics so as to vary the vernier range and angular displacement scales.

38 citations

Journal ArticleDOI
Peter Swerling1
10 Apr 1956
TL;DR: In this article, the limits imposed by receiver noise on the accuracy with which the angular position of a target can be determined by a pulsed search radar were investigated. And the relation between the estimation of angular position and the problem of target detection is discussed.
Abstract: An investigation is made of the limits imposed by receiver noise on the accuracy with which the angular position of a target can be determined by a pulsed search radar. Using a result in the theory of statistical estimation, a lower bound is derived for the standard deviation of regular unbiased estimates of target angular position, for a large class of methods of angular position determination; the lower bound depends on scan rate, pulse repetition rate, beamwidth, beam shape, and signal-to-noise ratio. A similar analysis is made of the limits on angular accuracy imposed by a combination of receiver noise and one particular type of target cross section fluctuation. Operations which can be performed on the received signal to form an estimate of target angular position, the standard deviation of which approximately attains the theoretical lower bound, are discussed. The relation between the estimation of angular position and the problem of target detection is discussed. A graphical presentation of the main results is given.

38 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202339
202282
2021106
2020164
2019224
2018212