75 results about "Stationary Reference Frame" patented technology

A 3-dimensional sonar system having a fixed frame of reference including a transmitter and receiver array. The system may include a single ping processor for processing received echoes from a single transmission including methods to match filter sonar sensor data, to optionally compensate for self Doppler, beamform sonar sensor data, to extract bottom targets from beamformed data and to extract in-water targets from the beamformed data. The system may also include a multi ping processor to operate on the outputs of multiple pings from the single ping processor including methods to detect tracks from in-water targets.

An imaging sonar system develops three-dimensional images of the space below, to the sides, and forward of a ship relative to a fixed frame of reference. Various features permit the system to be used in non-military environments and make possible low cost with substantial capabilities.

A method of starting a permanent magnet machine. A machine stator voltage in a stationary reference frame is sensed. An initial speed of a rotor of the machine is estimated based on the sensed voltage, and state variables of control algorithms are initialized based on the estimated initial speed. This method can provide smooth startup and / or restart at any speed.

The present invention is related to a process for the acquisition of information intended for the insertion of a locking screw into a distal locking hole of an endomedullary device, comprising the following steps: taking of two images of different orientations of the distal part of the said endomedullary device using a radioscopic unit; acquisition of the projection parameters especially the position of the X-ray source and of the projection plane, of each image by locating a fixed reference frame on the said endomedullary device and another fixed reference frame on said radioscopic unit; correction of any distortion of the images; segmentation of the distal part of the said endomedullary device in each image and calculation of the attributes relating to the position of the said device and to that of the holes, said attributes comprising at least the contours of the said device, its centre of gravity and its principal axis; construction of the projection cone of the distal part of the device for each image; determination of the intersection of the two projection cones; modelling of the said endomedullary device on the basis of the said intersection obtained in the preceding step; determination of the centre of the locking hole with the aid of the modelling obtained in the preceding step and of the centres of gravity of the holes determined on the images; and determination of the orientation of the locking orifice in an iterative manner.

A controller (130) for compensating reactive power and selected current load harmonics in an unbalanced multi-phase power distribution system. Control current is injected from a multi-phase voltage source inverter (118) into the multi-phase power distribution system as a function of the voltage and current provided by the source inverter 118. The injected current is operative to balance the load seen by the power distribution system including non-linear / distorted and unbalanced loads in each phase. The controller includes an inner loop control processor (216), an outer loop control processor, and an adaptation processor. The adaptation processor (238) is operative to estimate a selected set of predetermined harmonic components in the periodic disturbance which is a function of the unknown system parameters, the source current, the source voltage, and their time derivatives in stationary coordinates.

A method of starting a permanent magnet machine. A machine stator voltage in a stationary reference frame is sensed. An initial speed of a rotor of the machine is estimated based on the sensed voltage, and state variables of control algorithms are initialized based on the estimated initial speed. This method can provide smooth startup and / or restart at any speed.

Continuous monitoring and fault diagnosis of rotating machinery during variable speed operation is performed using only a position feedback signal. The position sensor generates a periodic waveform having multiple pulses per revolution of the machine. A circuit is included to detect, for example, a zero crossing or edge of the periodic waveform. At each detected zero crossing or edge, the time and position of the event is stored in memory. Other data, such as the current in the motor, may also be sampled and stored in memory. Because the sampled data is triggered by repeated feature of the position feedback signal, the sampled data is in a stationary reference frame in the position domain. Frequency analysis is performed on the sampled data, and the frequency components present in either the sampled signal are analyzed to identify the presence of a fault in the rotating machinery.

A method and system to digitally measure area / volume and body surface area of a person and estimate corresponding density and composition as related to a fixed reference frame. This Digital Image Volume Assessment System (DIVAS™) has many desirable features, such as computerized accuracy, precision, convenience, minimal operator expertise and subject compliance is required, and it is economical and expeditious.

A system for compensating orientation of a portable device is provided with a processing unit for: determining a roll rotation angle of the portable device in a mobile reference system associated thereto; and applying a rotation matrix, which is a function of the roll rotation angle, for transforming relative displacements of the mobile device in the mobile reference system into corresponding displacements in a fixed reference system, of an inertial type, thus compensating the orientation of the portable device. The processing unit determines the roll rotation angle, in the presence of dynamic acceleration, by means of: acquisition of a roll angular velocity of the portable device by a gyroscopic sensor fixed with respect thereto; and time integration of the same roll angular velocity.

Provided is a method for suppressing a circulating current in a modular multi-level converter for a high voltage direction-current (HVDC) transmission system. The HVDC transmission system converts an alternating current (AC) into a direct current (DC) and vice versa, transmits energy using a DC cable, and including a modular multilevel converter generating a high voltage source by stacking a plurality of sub-modules in series. In the circulating current suppression method, a circulating current (idiffj; j=a,b,c) of a,b,c phase in an abc 3-phase stationary reference frame, a DC current (idc) flowing in a DC cable, a current reference value (i*dc) of a DC component that needs to flow in the DC cable are inputted. The circulating current (idiffj) of the a,b,c phase is controlled to become zero. A compensation value (V*diffj) for suppressing a harmonic component of the circulating current is outputted.

Methods, systems and apparatus are provided for estimating electrical angular speed of a permanent magnet machine based on two-phase stationary reference frame feedback stator current samples, and a dimensionless gain (K) that is computed based on a sampling time (T) and machine parameters.

There is provided a method for estimating the orientation of an accelerometer relative to a fixed reference frame, the method comprising obtaining signals from the accelerometer, the signals indicating the components of the acceleration acting on the accelerometer along three orthogonal axes; identifying the axis with the highest component of acceleration; and determining the orientation of the accelerometer by determining the angle between the acceleration acting on the accelerometer and the axis with the highest component of acceleration. There is further provided a method for estimating the vertical acceleration in the fixed reference frame using the estimated orientation.

The present invention relates to an electrical power supply and control device (10) for equipment (9) of a rotor (5), the device having a three-phase AC generator (20) in a stationary frame of reference. The device (10) comprises a rotary field transformer (30) having a stationary portion (31) connected to said generator (20) and a rotary portion (32) connected to a sequencer (50) that is arranged in a rotary frame of reference, said device (10) including control means (51) for controlling the sequencer (50) and located in said stationary frame of reference, the control means being connected to the sequencer (50) via contactless connection means (200), said sequencer (50) being suitable for electrically powering said equipment (9) on order of said control means (51).

A short distance positioning system for a mobile object with respect to a fixed reference system. The mobile object is equipped with a probe, and at least one resonant circuit enabling reception of a magnetic field. A detection and comparison circuit detects the amplitude of the voltage induced at the terminals of the resonant circuit, thereby deducing the displacement of the probe with respect to the reference system.

The present invention relates to the electric energy transformation technology field, in particular to a voltage drop detection method suitable for a power grid voltage large harmonic content. The method comprises the steps of real-timely detecting a power grid voltage, calculating a positive sequence module value eP and a negative sequence module value eN of the power grid voltage, and carrying out the steady state judgment according to a calculation result; real-timely detecting the power grid voltage, calculating the voltage components e alpha and e beta of the power grid voltage in an alpha-beta stationary reference frame, carrying out the instant judgment according to the calculation result. When the instant judgment is used to limit an instant overcurrent, and the steady state judgment is used to determine a reactive current, the instant judgment pays attention to the rapidity, and the steady state judgment pays attention to the stability and accuracy. The two methods are combined to use, and make up the insufficiency mutually, thereby guaranteeing the accuracy and the stability of a judgment result.

A scanning force microscope (10) sometimes referred to as an atomic force microscope employs a laser (32) and a cantilever (28) which move proportionally to a moving reference frame (64). A fixed reference frame (11) contains optical components. A scanning mechanism creates relative movement between the fixed and moving reference frames. An optical assembly (114) is included which comprises at least one optical device in the fixed reference frame. The optical assembly permits initial alignment of the laser beam onto the cantilever and also permit the laser beam to follow the moving cantilever.

The invention discloses an improved method and device for sensing orientation of an object in space in a Working Reference Frame. The device of the invention includes an angular velocity sensor with at least two sensing axes and a linear acceleration sensor with at least three sensing axes. The method used for sensing orientation of the object in space in the Working Reference Frame uses synthetic values of the gravity component of the acceleration of the object. It depends upon the number of sensing axes of the angular velocity sensor and upon the dynamicity of the movement of the object. The dynamicity of the movement of the object is tested to compute the synthetic values which are used. The method and device of the invention allow control of a cursor on a display, independently of the roll imparted to the device by a user, in a seamless manner which is greatly improved over the devices and methods of the prior art.

A brushless double feed motor control device and a direct torque control method thereof. The device comprises a brushless double feed motor, a flux linkage, a torque observer, etc., wherein the torque observation is calculated under the stationary reference frames of a power winding and a control winding. The method comprises the following steps: the voltage and the current of the control winding, as well as the power winding are observed under a three-phase coordinate system and coordinate transformation is performed, so as to get the voltage and the current of the control winding, as well as the power winding under respective stationary reference frame; the flux linkages and the torques of the control winding and the power winding are calculated; and the voltage vector is selected through the sector the flux linkage is positioned which is determined by the flux linkage of the control winding, and the torque and flux linkage increments obtained by the demand and feedback of the torque, and those of the flux linkage of the control winding. By adopting the invention, the torque observation of the brushless double feed motor can be realized under the stationary reference frames of the power winding and the control winding, so as to avoid unstable observation results caused by rotational coordinate transformation and measuring error due to rotor angular velocity. The control system has simple structure and higher control accuracy.

At least one example embodiment discloses a drive system including a motor including a rotor, the motor configured to receive a measured current, a controller configured to generate a voltage for the motor at a stationary reference frame, the voltage having a frequency and the measured current being based on the voltage, a filter configured to obtain position information of the rotor based on the measured current and a nonlinear observer configured to estimate a rotor position of the motor during the stationary reference frame based on the position information. The controller is configured to control the motor based at least in part on the estimated rotor position.

A method of driving an alternating-current (AC) motor while periodically obtaining a rotator angle of the AC motor. The method includes: (a) driving the AC motor by a dS-axis voltage, which is a voltage for an exciting current in a stationary reference frame, and a qS-axis voltage, which is a voltage for generating a rotational force in the stationary reference frame, while sequentially applying different the dS-axis voltages and different qS-axis voltages to the AC motor in a control injection period; and (b) obtaining a rotator angle by a dS-axis voltage value, a qS-axis voltage value, a dS-axis current value, and a qS-axis current value in the control injection period.

A method of driving an alternating-current (AC) motor while periodically obtaining a rotator angle of the AC motor. The method includes: (a) driving the AC motor by a dS-axis voltage, which is a voltage for an exciting current in a stationary reference frame, and a qS-axis voltage, which is a voltage for generating a rotational force in the stationary reference frame, while sequentially applying different dS-axis voltages and different qS-axis voltages to the AC motor in a control injection period; and (b) obtaining a rotator angle by a dS-axis voltage value, a qS-axis voltage value, a dS-axis current value, and a qS-axis current value in the control injection period.

The present invention relates to a wind turbine and a method of operating a wind turbine for reducing edgewise vibrations, wherein the wind turbine comprises a wind turbine control system having at least one vibration sensor for measuring the edgewise vibrations and a controller for receiving the vibration signal from the vibration sensor. The sensor unit is preferably an accelerometer arranged in a stationary frame of reference. The controller determines at least one whirling mode frequency and the vibration level thereof. The controller initiates a corrective action if the measured vibration level exceeds a threshold value. The corrective action is preferably an adjustment of the pitch angle of the wind turbine blades which in turn dampens the edgewise vibrations.

The invention belongs to the field of shock-absorbing technology researches, and specifically relates to a metal rubber shock-absorbing energy-consuming device controlled by a shape memory alloy structure in a vibration manner. The metal rubber shock-absorbing energy-consuming device consists of rubber elements, an upper layer connection steel plate, a lower layer connection steel plate, shape memory alloy wire bundles, smooth round rings and pulley wheels, the rubber elements are connected with the upper layer connection steel plate and the lower layer connection steel plate, the lower layer connection steel plate is connected with a fixed reference system, the upper layer connection steel plate is connected with a bearing object, the smooth round rings are uniformly distributed and welded on the upper layer connection steel plate and the lower layer connection steel plate and sleeved with the pulley wheels, and the shape memory alloy wire bundles and the pulley wheels are arranged on the periphery of a supporting seat through the smooth round rings. The invention combines characteristics of superelasticity and energy consumption of shape memory alloy and provides a novel shock-absorbing energy-consuming supporting seat made of the shape memory alloy. The metal rubber shock-absorbing energy-consuming device has the advantages that by means of the superelasticity and the energy consumption of the shape memory alloy, the multi-dimensional shock insulation of the structure is achieved, and shock insulation effects are improved.

A 3D pointing device utilizing an orientation sensor, capable of accurately transforming rotations and movements of the 3D pointing device into a movement pattern in the display plane of a display device is provided. The 3D pointing device includes the orientation sensor, a rotation sensor, and a computing processor. The orientation sensor generates an orientation output associated with the orientation of the 3D pointing device associated with three coordinate axes of a global reference frame associated with the Earth. The rotation sensor generates a rotation output associated with the rotation of the 3D pointing device associated with three coordinate axes of a spatial reference frame associated with the 3D pointing device itself The computing processor uses the orientation output and the rotation output to generate a transformed output associated with a fixed reference frame associated with the display device above. The transformed output represents a segment of the movement pattern.