1. A valve position controller comprising:
a brushless motor having three-phase stator coils constituting an armature winding, and a magnet rotor disposed so as to rotate relative to the stator coils and holding a plurality of permanent magnets for constituting field poles;
a valve driven by the brushless motor;
rotor position detection means for producing signals corresponding to the rotational position of the magnet rotor relative to the three-phase stator coils;
valve position calculation means for calculating the present position of the valve based on the signals output from the rotor position detection means;
control quantity calculation means for calculating the valve position control quantity to eliminate the difference between the present position of the valve calculated by the valve position calculation means and the target control value, and for calculating the motor current control quantity based on the calculated valve position control quantity; and
a motor drive circuit for selectively driving the stator coils of two phases among the stator coils of the three phases based on signals output from the rotor position detection means and on the motor current control quantity calculated by the control quantity calculation means.
2. A valve position controller according to claim 1, wherein
the motor current control quantity includes the duty ratio and the direction of current or includes the amount of current and the direction of current of the motor driving current fed to the stator coils of two phases among the three-phase stator coils, which is set to eliminate the difference between the present position of the valve calculated by the valve position calculation means and the target control value.
3. A valve position controller according to claim 1, wherein
the rotor position detection means has noncontact-type magnetic detector elements that generate an electromotive force upon sensing a magnetic field generated by the plurality of permanent magnets, or produce electric signals corresponding to the density of a magnetic flux that intersects; and
the magnetic detector elements are arranged in a plural number so as to face the magnet rotor.
4. A valve position controller according to claim 3, wherein
the valve position calculation means has a counter for counting the number of shifts of the conditions of electric signals output from the magnetic detector elements; and
the present position of the valve is calculated based on the counted number of the counter.
5. A valve position controller according to claim 4, wherein
when the shifts of the states of electric signals output from the magnetic detector elements are skipped, the valve position calculation means increases or decreases the counted number of the counter by an amount that is skipped.
6. A valve position controller according to claim 4, further comprising:
first malfunction discrimination means for discriminating whether the conditions of electric signals output from the magnetic detector elements are abnormal or normal; and
second malfunction discrimination means for discriminating whether the order of shifts of the conditions of electric signals output from the magnetic detector elements is abnormal or normal,
wherein when the order of shifts of the conditions of electric signals output from the magnetic detector elements is determined by the second malfunction discrimination means to be abnormal, the valve position calculation means executes again or learns again the reference position learn control to learn the reference position of the magnet rotor.
7. A valve position controller according to claim 1, further comprising:
malfunction detection means for detecting abnormal input that greatly exceeds an estimated load torque based on a counter electromotive force produced by the motor driving current flowing into the three-phase stator coils,
wherein, when the abnormal input greatly exceeding the estimated load torque is detected by the malfunction detection means, the valve position calculation means executes again or learns again the reference position learn control to learn the reference position of the magnet rotor.
8. A valve position controller according to claim 4, further comprising:
a power transmission mechanism for transmitting the rotational output of the brushless motor to the valve; and
malfunction detection means for detecting the malfunction in the power transmission mechanism when the counted number of the counter is deviated from the predetermined range or when the electric signals output from the magnetic detector elements continue to shift the conditions for longer than a predetermined period of time during the reference position learn control for learning the reference position of the magnet rotor.
9. A valve position controller according to claim 3, wherein the valve position calculation means shortens the period for sampling the electric signals output from the magnetic detector elements to be shorter than a minimum period of shift of the conditions of electric signals output from the magnetic detector elements.
10. A valve position controller according to claim 1, wherein
the rotor position detection means includes three magnetic detector elements that generate an electromotive force upon sensing a magnetic field generated by the plurality of permanent magnets, or produce electric signals corresponding to the density of a magnetic flux that intersects; and
when one magnetic detector element is detected to be malfunctioning among the three magnetic detector elements, the valve position calculation means counts the number of shifts of the conditions of electric signals output from the remaining two magnetic detector elements to calculate the present position of the valve.
11. A valve position controller according to claim 1, wherein
at least two or more functions of the valve position calculation means, the control quantity calculation means, and the motor drive circuit are integrated on one chip.
12. A valve position controller according to claim 11, wherein
the brushless motor has a motor shaft that is integral with the magnet rotor, and a cylindrical motor housing that rotatably supports both ends of the motor shaft in the axial direction; and
at least two or more functions of the valve position calculation means, the control quantity calculation means and the motor drive circuit integrated on one chip, as well as the function of the rotor position detection means, are contained in the motor housing.
13. A valve position controller according to claim 1, further comprising:
a reduction gear mechanism which reduces the rotational speed of the magnet rotor by a predetermined reduction ratio and transmits it to the valve, and a spring for urging the valve in a direction in which it opens or in a direction in which it closes, wherein
the valve position calculation means executes a reference position learn control to learn the reference position of the magnet rotor in a state where the valve is positioned in a direction against the urging direction of the spring.
14. A valve position controller according to claim 1, further comprising a valve housing forming an air passage through which the air flows, wherein
the valve is a flow rate control valve for controlling the flow rate of the air that flows through the air passage.
15. A valve position controller according to claim 1, further comprising a valve housing forming an intake air passage communicated with the intake ports of an internal combustion engine, wherein
the valve is an air control valve that produces a swirling stream of the air flowing into the combustion chamber from the intake port of the internal combustion engine.
16. A valve position controller according to claim 1, further comprising an intake manifold forming an intake air passage communicated with the combustion chambers of an internal combustion engine, wherein
the valve is a variable intake valve which opens and closes the intake air passage to vary the length or the opening area of the intake air passage.
17. A valve position controller according to claim 1, further comprising a throttle body forming a throttle bore of a circular shape in cross section communicated with the combustion chambers of an internal combustion engine, wherein
the valve is a disk-shaped throttle valve for adjusting the amount of the intake air flowing through the throttle bore.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A method for measuring of arterial pulse comprising steps of:
obtaining a sequence of thermal infrared images from a subject, wherein each said thermal infrared image is obtained without skin contact with said subject;
performing a first analysis of said sequence of obtained thermal infrared images to detect at least one region of interest for further analysis;
performing a second analysis of said sequence of obtained thermal infrared images to track said at least one region of interest, wherein said second analysis includes detecting a corresponding spatial location of each of said at least one region of interest;
performing a third analysis of said at least one region of interest to select at least one configuration of a region of measurement of arterial pulse within said corresponding region of interest; and
determining at least one arterial pulse waveform from said selected configuration of region of measurement.
2. The method according to claim 1, wherein said first analysis includes automatic selection of a pixel area using multiscale image decomposition and multiresolution analysis.
3. The method according to claim 2, wherein:
said multiscale decomposition analysis includes at least one of the following: Laplacian pyramid structures, Gaussian pyramid structures, Gradient Pyramid structures, ratio-of-low pass pyramid structures and wavelet decomposition schemes; and
said multiresolution analysis includes application of convolution filters to determine said at least one region of interest.
4. The method according to claim 1, wherein said second analysis automatically tracks said at least one region of interest on every thermal infrared image using at least one of the following: Laplacian pyramid structures, Gaussian pyramid structures, gradient pyramid structures, ratio-of-low pass pyramid structures and wavelet decomposition schemes; and
said multiresolution analysis includes application of convolution filters to \u201cdetermine salient, robust and permanent features for tracking of said region of interest.
5. The method according to claim 1, wherein said second analysis automatically tracks said at least one region of interest on every thermal infrared image using at least one of the following: Laplacian pyramid structures, Gaussian pyramid structures, gradient pyramid structures, ratio-of-low pass pyramid structures and wavelet decomposition schemes; and
said multiresolution analysis includes application of convolution filters for identification and configurations of said region of measurement.
6. The method according to claim 1, wherein said second analysis automatically tracks said at least one region of interest on every thermal infrared image using at least one of the following: Laplacian pyramid structures, Gaussian pyramid structures, gradient pyramid structures, ratio-of-low pass pyramid structures and wavelet decomposition schemes; and
said multiresolution analysis includes application of convolution filters for identification of arterial pulse structures in measurement of arterial pulse waveforms.
7. The method according to claim 1, wherein said second analysis automatically tracks said at least one region of interest on every thermal infrared image using at least one of the following: Laplacian pyramid structures, Gaussian pyramid structures, gradient pyramid structures, ratio-of-low pass pyramid structures and wavelet decomposition schemes; and
said multiresolution analysis includes application of convolution filters for determining periodicity measures for the arterial pulse waveforms measured from a plurality of said configurations.
8. The method according to claim 1, wherein said second analysis automatically tracks said at least one region of interest on every thermal infrared image using at least one of the following: Laplacian pyramid structures, Gaussian pyramid structures, gradient pyramid structures, ratio-of-low pass pyramid structures and wavelet decomposition schemes; and
said multiresolution analysis includes application of convolution filters for filtering the arterial pulse waveforms to minimize noise and data irrelevant to arterial pulse structures.
9. The method according to claim 1, wherein said second analysis automatically tracks said at least one region of interest on every thermal infrared image using at least one of the following: Laplacian pyramid structures, Gaussian pyramid structures, gradient pyramid structures, ratio-of-low pass pyramid structures and wavelet decomposition schemes; and
said multiresolution analysis includes application of convolution filters for accurate localization of arterial pulse peaks within the arterial pulse waveform.
10. The method according to claim 1, wherein said second analysis automatically tracks said at least one region of interest on every thermal infrared image to establish a spatial location of said at least one region of interest on every frame.
11. The method according to claim 1, wherein said second analysis comprises:
making use of a global and local tracker to perform a robust tracking of said at least one region of interest.
12. The method according to claim 1, wherein said third analysis automatically identifies said at least one configuration of a region of measurement of the arterial pulse using quasi-periodic nature of the arterial pulse.
13. The method according to claim 1, wherein said at least one region of interest is a region in a vicinity of major superficial arteries of said subject
14. The method according to claim 13, wherein said region of interest corresponds to one of the following: a superficial temporal artery, a frontal branch of a superficial temporal artery, a carotid artery, a radial artery of an arm and a brachial artery of an arm.
15. The method according to claim 1, wherein said third analysis comprises:
performing at least one multiscale decomposition with at least one appropriate decomposition function at each frame of said thermal infrared images;
constructing various configurations of said region of measurement in terms of at least one of scale, orientation, size and location, within limits of said at least one tracked region of interest;
computing the arterial pulse waveform from every said region of measurement configuration;
applying continuous wavelet analysis to every said arterial pulse waveform to detect arterial pulse structures;
running a periodicity detection algorithm on every set of said detected arterial pulse structures;
computing a periodicity measure for every said set of detected arterial pulse structures; and
selecting and outputting at least one optimal region of measurement configurations based on said computed periodicity measure.
16. The method according to claim 1, wherein said third analysis comprises:
performing analysis of said sequence of obtained thermal infrared images to identify heat patterns which are triggered by effects of arterial pulse propagation;
computing raw arterial pulse waveforms from a plurality of configurations of said region of measurement based on at least one of: scale, orientation, topology, size, location;
estimate a confidence score for every computed raw arterial pulse waveform, where said confidence score represents a certain degree of relevance to pulsatile nature of arterial pulse phenomena;
identifying at least one appropriate configuration of region of measurement based on comparing said estimated confidence scores for every configuration of region of measurement;
outputting one or more of said appropriate configurations of region of measurement for determining the arterial pulse.
17. The method according to claim 1, wherein said step of obtaining a sequence of infrared thermal images is performed by measuring and imaging the thermal infrared energy naturally radiated from said subject, without projecting any kind of energy to said subject.
18. The method according to claim 1, wherein said step of determining an arterial pulse waveform determines the arterial pulse waveform based on measurement of thermal variations caused by arterial blood pressure wave propagation.
19. A system for obtaining an arterial pulse waveform comprising:
a non-contact and passive thermal radiation imaging sensor configured and arranged to obtain a sequence of thermal infrared images of a subject containing one or more regions of interest;
means for thermal infrared data translation, storing, processing and retrieving of the obtained sequence of thermal infrared images;
means for detecting at least one region of interest in the obtained sequence of thermal infrared images means for tracking aid at least one region of interest in the obtained sequence of thermal IR images
means for identification of one or more of faithful configurations of region of measurement using pulsatile nature of arterial pulse phenomena; and
means for determining the arterial pulse by analyzing the faithful configuration of region of measurement.
20. The system according to claim 19, wherein said thermal infrared images comprise electromagnetic wavelengths between approximately 3-5 \u03bcm and 8-14 \u03bcm.
21. A system for obtaining a pulse waveform comprising:
a thermal sensor configured and arranged to obtain an image of an observation area of skin;
means for automatically detecting a region of measurement, which is defined as a smaller area within said observation area, using the quasi-periodic nature of thermal patterns obtained from said thermal sensor; and
means for determining a pulse waveform by analyzing said region of measurement.
22. The system according to claim 21, wherein:
said thermal patterns comprise wavelengths between approximately 8 \u03bcm and approximately 14 \u03bcm; and
said thermal patterns are arterial thermal patterns.
23. A method for measuring heart function, comprising the steps of:
obtaining a sequence of infrared thermal images of an observation area of skin;
decomposing said sequence of infrared thermal images into a set of representations of a plurality of different scales;
selecting an appropriate scale representation on the basis of amount of heat information relevant to a pulse waveform; and
determining a pulse waveform using said selected scale representation.
24. The method according to claim 23, wherein:
said plurality of different scales includes at least a first scale and a second scale, where said second scale is more fine than said first scale;
said second scale is selected during said selecting step; and
using said first scale for tracking, from frame to frame, a region of interest within the observation area.