CN102355183A - Method for detecting position of hub of hub motor of a PET-CT (positron emission tomography-computed tomography) machine - Google Patents

Abstract

The invention relates to a method for detecting the position of a hub of a hub motor of a PET-CT (positron emission tomography-computed tomography) machine. According to the method, an absolute position sensor is added on the hub motor of a PET-CT machine on the basis of original three position sensors with a reversing function, then the absolute position sensor controls the motor in cooperation with a position detection ring arranged on a rotor of the hub motor of the PET-CT machine so as to meet the position detection accuracy requirement. an electromagnetic signal is generated under the electromagnetic induction action between the absolute position sensor and a magnetic steel pole of the absolute position detection ring of the hub motor of the PET-CT machine, and the absolute position, rotating speed, precision and rotating direction of the hub motor of the PET-CT machine can be determined according to a relation between the electromagnetic signal and a signal of a reversing position sensor. By using the method provided by the invention, the hub motor of the PET-CT machine can be ensured to operate normally under the condition of high-precision positioning, and the real-time detection and position adjustment on the PET-CT machine can be realized, thereby facilitating the improvement of scanning precision, and greatly reducing the equipment cost.

Description

A kind of method for detecting position of PET-CT wheel hub motor wheel hub

Technical field

The present invention relates to motor location and rotating speed and detect applied technical field, particularly relate to a kind of method for detecting position of PET-CT wheel hub motor wheel hub.

Background technology

The PET-CT machine to the On-line Control of its motor speed and position, is that to guarantee that the PET-CT machine can form images when doing diagnosis to the patient clear, accurate in running, avoids taking place the mistaken diagnosis phenomenon.

In the PET-CT machine course of work; Rotary speed is extremely important and must a consider technological parameter; The precision of rotating speed and the stable correctness and the accuracy of judging pathology that is directly connected to the imaging of PET-CT machine; Therefore when the PET-CT machine is worked; To the accurate measurement and the control of wheel hub motor rotating speed on the PET-CT machine, seem particularly important.

At present, generally be that price is controlled rotating speed of motor with the motor speed regulation system of relatively costly photoelectric encoder on the PET-CT machine.Now; Along with the fast development of electrical technology, computer technology and control theory and perfect; Having promoted electric machines control technology develops towards high accuracy, high accuracy and high reliability direction; In addition; Because the continuous development of medical level and patient impel medicine equipment to develop towards high accuracy, high reliability and low-cost direction to the requirement of pathological diagnosis accuracy.At present, straight drive system is used on the PET-CT machine widely, because bore is big, resolution requirement is high, directly adopts photoelectric encoder, resolver or grating, then can cause use cost too high.Each factory commercial city is the various method for detecting position of research.

Summary of the invention

Technical problem to be solved by this invention provides a kind of method for detecting position of PET-CT wheel hub motor wheel hub, can be more accurately, more delicately wheel hub motor is controlled.

The technical solution adopted for the present invention to solve the technical problems is: a kind of method for detecting position of PET-CT wheel hub motor wheel hub is provided, may further comprise the steps:

(1) the motor position detection ring is installed on the rotor of wheel hub motor, and corresponding position transducer is installed on frame;

(2) start the PET-CT machine;

(3) position transducer detects electromagnetic signal; Judge through the position sensor signal of absolute position whether the PET-CT machine reaches its initial alignment position; If reach position location and rotating speed requirement then begin to get into next step; The PET-CT machine begins to get into detected state, otherwise PET-CT wheel hub motor continues operation and keep detected state to wait for;

(4) relative position sensor of Control current commutation calculates the mechanical angle that PET-CT machine rotor relative positioning position turns over through detecting electromagnetic signal; And judge that PET-CT machine rotating speed and angular displacement are whether in the error range that the PET-CT machine is allowed; If would get into next step, otherwise keep detected state;

(5) the motor speed control system is controlled motor speed, makes its stabilization of speed in the speed error scope that the PET-CT machine is allowed.

The relative position sensor of three commutator effects is separated by 120 ° and is placed in described step (1), and absolute position transducer aligns with initial position, guarantees installation accuracy.

In described step (1), the motor position detection ring being magnetized is absolute position detection ring and relative position detection ring, and wherein the absolute position detection ring has only a pair of magnetic pole.

Position transducer is N type Hall switch formula position transducer or variable reluctance position transducer in described step (3).

Absolute position transducer in described step (3) (N type Hall switch formula position transducer) changes the level saltus step that causes through the magnetic pole N utmost point to the S utmost point and confirms PET-CT machine rotor initial position through the detection to the absolute position detection ring.

Following equality is satisfied in the mechanical angle displacement of PET-CT machine in described step (4):

$\mathrm{\ψ}=\frac{\mathrm{\θ}}{6}=\frac{\mathrm{\α}}{6\·p}$

ε＝ψ·ρ

ε′＝K·ε

Wherein, ψ changes corresponding mechanical angle displacement for the relative position sensor signal; θ changes the mechanical angle displacement of one-period for the relative position sensor signal; α is an electrical degree; P is a relative position detection ring number of pole-pairs, and ρ is a control precision, and ε is the theoretical position precision; ε ' is the physical location precision, and K is a coefficient of safety.

Beneficial effect

Owing to adopted above-mentioned technical scheme, the present invention compared with prior art has following advantage and good effect: the present invention locatees and detects motor speed through the method that absolute position transducer is installed on the wheel hub motor wheel hub.Behind the starter motor; Will produce an electromagnetic signal and realize initial alignment through waiting for that the every fortune of absolute position detection ring circles motor rotation; Electromagnetic signal is converted into the rotating speed of motor signal; Can detect the speed of each commentaries on classics of motor fast, easily; Reach after the Testing requirement, PET-CT wheel hub motor stabilizing operates in the measurement state and begins and detects.In addition, the motor speed control system will be revised the rotating speed of each commentaries on classics of motor, in order to avoid the PET-CT machine rotating speed deviation occurs when operation, causes imaging inaccurate.Therefore; Detection method through absolute position transducer is installed on the wheel hub motor wheel hub has the control precision height; Response speed is fast; Characteristics such as stability is strong, and the position probing ring is easy for installation; Feasibility is high; Can realize the integrated of position transducer, simultaneously, utilization PET-CT wheel hub motor and control system thereof replace large photoelectric encoder motor and control system thereof greatly to reduce cost.

Description of drawings

Fig. 1 is PET-CT wheel hub motor position sensor work period figure of the present invention (p=2);

Fig. 2 is motor position detection ring figure of the present invention;

Fig. 3 is a motor position layout of the present invention.

Embodiment

Below in conjunction with specific embodiment, further set forth the present invention.Should be understood that these embodiment only to be used to the present invention is described and be not used in the restriction scope of the present invention.Should be understood that in addition those skilled in the art can do various changes or modification to the present invention after the content of having read the present invention's instruction, these equivalent form of values fall within the application's appended claims institute restricted portion equally.

Shown in Fig. 1-3; The present invention relates to a kind of method for detecting position of PET-CT wheel hub motor wheel hub; This method is on the position transducer basis of original three the commutation effects of PET-CT wheel hub motor, to increase an absolute position transducer, and collaborative PET-CT wheel hub motor position detection ring control motor is to reach the position detection accuracy requirement.This absolute position transducer and PET-CT wheel hub motor absolute position detection ring magnet steel magnetic pole produce electromagnetic signal through the electromagnetic induction effect, this signal through and the commutation position sensor signal between relation can confirm absolute position, rotating speed, the precision of PET-CT wheel hub motor and turn to.Before adopting this method to detect, need accurately locate the bulb of PET-CT machine, Dui Ying PET-CT wheel hub motor absolute position detection ring initial position also will be set with it.Adopt this method to detect and guarantee that not only PET-CT wheel hub motor can normally move under high-precision location positioning, also can realize simultaneously the real-time detection and the position adjustment of PET-CT machine are helped improving scanning accuracy, greatly reduced equipment cost.

Its concrete steps comprise:

(1) the motor position detection ring is installed on the rotor of wheel hub motor, and corresponding position transducer is installed on frame;

(2) start the PET-CT machine;

(3) position transducer detects electromagnetic signal; Judge through the position sensor signal of absolute position whether the PET-CT machine reaches its initial alignment position; If reach position location and rotating speed requirement then begin to get into next step; The PET-CT machine begins to get into detected state, otherwise PET-CT wheel hub motor continues operation and keep detected state to wait for;

(4) relative position sensor of Control current commutation calculates the mechanical angle that PET-CT machine rotor relative positioning position turns over through detecting electromagnetic signal; And judge that PET-CT machine rotating speed and angular displacement are whether in the error range that the PET-CT machine is allowed; If would get into next step, otherwise keep detected state;

(5) the motor speed control system is controlled motor speed, makes its stabilization of speed in the speed error scope that the PET-CT machine is allowed.

In conjunction with shown in Figure 1, behind the startup PET-CT wheel hub motor, aliging with absolute position transducer in wait motor initial alignment position, will satisfy the motor speed requirement simultaneously.After motor operating state meets the demands; The PET-CT machine gets into detected state; The operation of three the collaborative motor speed control system control of relative position sensor motors, absolute position transducer is revised motor speed after motor whenever turns around, and eliminates accumulation angular displacement error.Depending on the mechanical angular displacement

there

motor angular displacement absolute accuracy of mechanical angular displacement and control accuracy of the product.Meanwhile; Counter begins A position relative position sensor is wherein counted; It increases the then corresponding electrical angle of a numerical value and increases by 360 °, and mechanical angle increase

can calculate the relative angular displacement of PET-CT wheel hub motor thus accurately.

In addition, with angular displacement absolute measurement precision be ± 1 ' PET-CT wheel hub motor be example, satisfy according to the electromechanics angular displacement:

$\mathrm{\ψ}=\frac{\mathrm{\θ}}{6}=\frac{\mathrm{\α}}{6\·p}$

ε＝ψ·ρ

ε′＝K·ε

Get K=2 according to actual engine request, ρ=1%, ε '=1 ' time, calculating and answering power taking machine number of pole-pairs is 72 pairs.It is thus clear that on the basis that the transducer control precision does not promote, relative position detection ring number of pole-pairs is many more, the angular displacement precision of motor is also just high more.After rotor rotates a circle; Can utilize angular displacement and the speed of relation through closed-loop control adjustment motor between PET-CT wheel hub motor absolute position detection ring and the absolute position transducer, improve the positional precision of PET-CT wheel hub motor greatly.

Be not difficult to find; Compare with conventional detection; The maximum characteristics of the present invention are to detect the rotating speed of each commentaries on classics of wheel hub motor on the PET-CT machine; And in time the rotating speed of each commentaries on classics is revised through the motor speed control system; The rotating speed that guarantees each commentaries on classics of wheel hub motor can both be in the error range of predetermined set; Thereby guaranteed the accuracy of PET-CT machine imaging; Simultaneously, utilization PET-CT wheel hub motor and control system thereof replace large photoelectric encoder motor and control system thereof greatly to reduce cost.Characteristics such as therefore, be used in the detection method that absolute position transducer is installed on the PET-CT wheel hub motor outer shroud and have the control precision height, response speed is fast, and is stable strong, and cost is relatively low.

Claims (6)

1. the method for detecting position of a PET-CT wheel hub motor wheel hub is characterized in that, may further comprise the steps:

(1) the motor position detection ring is installed on the rotor of wheel hub motor, and corresponding position transducer is installed on frame;

(2) start the PET-CT machine;

(3) position transducer detects electromagnetic signal; Judge through the position sensor signal of absolute position whether the PET-CT machine reaches its initial alignment position; If reach position location and rotating speed requirement then begin to get into next step; The PET-CT machine begins to get into detected state, otherwise PET-CT wheel hub motor continues operation and keep detected state to wait for;

(4) relative position sensor of Control current commutation calculates the mechanical angle that PET-CT machine rotor relative positioning position turns over through detecting electromagnetic signal; And judge that PET-CT machine rotating speed and angular displacement are whether in the error range that the PET-CT machine is allowed; If would get into next step, otherwise keep detected state;

(5) the motor speed control system is controlled motor speed, makes its stabilization of speed in the speed error scope that the PET-CT machine is allowed.

2. the method for detecting position of PET-CT wheel hub motor wheel hub according to claim 1 is characterized in that, the relative position sensor of three commutator effects is separated by 120 ° and is placed in the described step (1), and absolute position transducer aligns with initial position.

3. the method for detecting position of PET-CT wheel hub motor wheel hub according to claim 1; It is characterized in that; In the described step (1) the motor position detection ring being magnetized is absolute position detection ring and relative position detection ring, and wherein the absolute position detection ring has only a pair of magnetic pole.

4. the method for detecting position of PET-CT wheel hub motor wheel hub according to claim 1 is characterized in that, position transducer is N type Hall switch formula position transducer or variable reluctance position transducer in the described step (3).

5. the method for detecting position of PET-CT wheel hub motor wheel hub according to claim 1; It is characterized in that absolute position transducer is that N type Hall switch formula position transducer is confirmed PET-CT machine rotor initial position through the detection and the magnetic pole N utmost point to the absolute position detection ring to the level saltus step that the transformation of the S utmost point causes in the described step (3).

6. the method for detecting position of PET-CT wheel hub motor wheel hub according to claim 1 is characterized in that, following equality is satisfied in the displacement of PET-CT machine mechanical angle in the described step (4):

$\mathrm{\ψ}=\frac{\mathrm{\θ}}{6}=\frac{\mathrm{\α}}{6\·p}$

ε＝ψ·ρ

ε′＝K·ε

Wherein, ψ changes corresponding mechanical angle displacement for the relative position sensor signal; θ changes the mechanical angle displacement of one-period for the relative position sensor signal; α is an electrical degree; P is a relative position detection ring number of pole-pairs, and ρ is a control precision, and ε is the theoretical position precision; ε ' is the physical location precision, and K is a coefficient of safety.

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