JP2006349591A - Rotary sensor and mobile body system for vehicle using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rotary sensor with high resolution using a resolver for position detection. <P>SOLUTION: The rotary sensor comprises: the resolver 2 outputting sine wave and cosine wave voltages by input of one phase of sinusoidal voltage; an A/D converter 18 A/D converting the output; a calculation part 17 calculating an angle of a drive shaft from the output; a rectangular wave generation part 14 generating a rectangular wave synchronously with the A/D converter 18; and an excited wave generation part 1 generating the sinusoidal voltage to be input to the resolver 2 from the rectangular wave. In this sensor, after the first step of determining a quadrant of rotating angle of the drive shaft and the second step of determining on which side the rotating angle of the drive shaft is present when the determined quadrant is further equally halved are performed, the angle of the drive shaft is calculated according to the determination result. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a rotation sensor and a vehicle moving body system using the rotation sensor. More specifically, the present invention relates to a rotation sensor for detecting a rotation angle of a shaft using a resolver, and a vehicle moving body system for driving a moving body such as a slide door using the sensor.

  For the detection of the position of the sliding door, the speed control for opening and closing the sliding door performed based on the position detection, and the reversal control at the time of pinching, a drive element such as a motor shaft of the sliding door has a hall element or an optical type Detection devices such as pulse encoders are used. On the other hand, as a rotation sensor, there is one using a resolver as a motor position detection device in addition to a Hall element or an optical pulse encoder. This includes an R / D (resolver / digital) converter for digital conversion of analog output output from the resolver, a motor shaft angle calculation unit, an excitation sine wave generation unit, and the like.

  The angle of the motor rotation shaft can be detected with high resolution by using a device using a Hall element or an optical pulse encoder as described above. However, if the resolution is to be increased, the number of Hall elements, etc. In addition, the accuracy of the arrangement and the like is required. In order to solve such a problem, a high resolution can be obtained by using a detection device such as a resolver. However, such a detection device is provided with an expensive DSP (digital signal processor) or the like. Therefore, the resolution obtained from the rotation is 4000 divisions per rotation, which is unsuitable and expensive for a vehicle door that does not require such high resolution.

  However, in addition to the sliding door driven by the motor, in order to ensure the safety of the back door and the trunk lid behind the vehicle, it is necessary to reduce the pinching load based on high resolution and positional accuracy. In order to be mounted on a vehicle, a small and highly reliable sensor is required.

  With this background, the present invention uses a resolver to detect the position of a vehicle moving body, and does not use an expensive device such as a DSP as an R / D converter. Another object of the present invention is to provide a rotation sensor that is a small, highly reliable, and high-resolution position detecting device, and thereby to provide a vehicle moving body system with high safety.

  A rotation sensor according to the present invention (Claim 1) includes a resolver that outputs a sine wave and a cosine wave voltage by a one-phase sine wave voltage input and a sine of the drive shaft in order to detect a rotation angle of the drive shaft An A / D converter for A / D converting the output of the wave and cosine wave voltage, a calculation unit for calculating the angle of the drive shaft from the output of the A / D converter, and a rectangular wave in synchronization with the A / D converter And an excitation wave generation unit that generates a sine wave voltage to be input to the resolver from the rectangular wave, and the A / D converter, the calculation unit, and the rectangular wave generation unit are configured by a microcomputer. When the calculation unit divides the quadrant of the rotation angle of the drive shaft from the output of the A / D converted sine wave and cosine wave voltage and further divides the determined quadrant into two equal parts Of the drive shaft Rolling after the angle has undergone the second stage determines whether to either side, and calculates the angle of the drive shaft in accordance with the determination result.

  In such a rotation sensor, the microcomputer stores a table for searching the drive shaft angle corresponding to the sine wave and cosine wave voltages in the calculation unit according to the determination result. What has a memory | storage part (Claim 2) is preferable.

  A vehicle moving body system according to the present invention (Claim 3) includes the above-described rotation sensor, a drive motor for driving the drive shaft, a vehicle moving body operated by the drive motor, and opening and closing of the vehicle moving body. It is characterized by having a control part which controls. Further, the vehicle moving body in the vehicle moving body system using such a rotation sensor may be either a slide door provided on the side surface of the vehicle, a back door provided on the rear side of the vehicle, or a trunk lid. Item 4).

  Since the rotation sensor of the present invention (claim 1) processes the sine wave and cosine wave voltage output of the resolver using a microcomputer, it can detect the position with high resolution with a simple configuration and is an inexpensive sensor.

  In addition, the microcomputer includes a storage unit that stores a table for searching the angle of the drive shaft corresponding to the sine wave and cosine wave voltages of the drive shaft in the calculation unit according to the determination result. (Claim 2) enables a high-speed response.

  In the vehicle moving body system according to the present invention (Claim 3), the position of the moving body is detected by the above-described rotating sensor, so that the position detection accuracy of the vehicle moving body can be improved. For this reason, it is possible to control the speed with high accuracy, and it is also possible to reduce the detection load of pinching. Further, the size of the position detection device can be reduced.

  When the vehicle moving body is a slide door, a back door or a trunk lid provided at the rear side of the vehicle (Claim 4), the position detection accuracy of the moving body can be improved similarly to the above, By reducing the detected load, a safe vehicle moving body system is obtained.

  Next, an embodiment of the rotation sensor of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of a rotation sensor of the present invention, FIG. 2 is a partially cutaway perspective view showing an example of a resolver, and FIG. 3 is a flowchart showing a first stage of a calculation unit of the rotation sensor of FIG. 4 is a flowchart showing the first quadrant of the second stage of the calculation unit of the rotation sensor of FIG. 1, and FIG. 5 is a flowchart showing the third quadrant of the second stage of the calculation unit of the rotation sensor of FIG. .

  First, the rotation sensor A of the present invention will be described with reference to FIGS. The rotation sensor A includes an excitation wave generator 1, a resolver 2 excited by the excitation wave generated by the excitation wave generator 1, an output circuit 3 for processing an output from the resolver 2, and an output circuit thereof 3 is a microcomputer 4 that calculates an output obtained from the computer 3.

  An excitation wave generating unit 1 shown in FIG. 1 has a frequency dividing circuit 15 that divides a rectangular wave generated by a rectangular wave generating unit inside a microcomputer, which will be described later, and a low-pass filter 16 (hereinafter referred to as LPF) following the frequency dividing circuit 15. And a buffer amplifier 7 following the LPF 16. The generated rectangular wave is divided by the frequency dividing circuit 15. This frequency-divided rectangular wave becomes an input sine wave 11 by the LPF 16 and the subsequent buffer amplifier 7. A sine wave can be generated directly from the microcomputer 4 instead of the rectangular wave.

  FIG. 2 shows an example of a brushless resolver. This has a shaft 20 and a resolver 2 disposed at the rear end of the shaft 20. The resolver 2 includes a stator 5 and a rotor 6. The stator 5 has a cylindrical shape having an opening for rotatably holding the rotor 6 at the center, and two sets of output coils 8 and 9 are arranged at an angle of 90 degrees on the peripheral edge of the cylindrical shape. ing. The rotor 6 is provided with an exciting coil 10 that rotates as the rotor 6 rotates.

  In the brushless resolver configured as described above, when an AC voltage is applied to the rotor 6 and the rotor 6 is rotated together with the shaft 20, a voltage having a phase difference corresponding to the rotation angle is induced in the stator 5. The rotation angle is obtained by taking out this phase difference. The output circuit 3 amplifies the output voltage having such a phase difference, and then transmits the output to the microcomputer 4.

  The microcomputer 4 includes an A / D converter 18, a calculation unit 17, an output port 19, and a rectangular wave generation unit 14 therein. The microcomputer 4 has a central processing unit and peripheral circuits of a computer integrated on a single chip IC, for example, RAM, ROM, CPU, A / D converter, and time interval, and counts external signal pulses. Timers, counters, etc. are arranged. The microcomputer 4 can also serve as a motor control microcomputer.

  The output obtained from the output circuit 3 is first A / D converted by the A / D converter 18. Next, the rotation angle is calculated from the A / D converted information obtained by the calculation unit 17. The calculation unit 17 includes a calculation unit 21 for determining a rotation angle based on information obtained from the A / D converter 18 and a table 22 that is referred to based on the obtained information and the calculation result of the calculation unit 21. is there. The table 22 is composed of several types of tables in which the relationship between the obtained information and the rotation angle is accumulated. The rectangular wave generator 14 generates a rectangular wave at every time interval generated by a counter or the like inside the microcomputer, and the generated rectangular wave is sent to the excitation wave generator 1 described above. The excitation sine wave is input to the rotor 6 of the resolver 2.

  Returning to FIG. 1, the operation of the rotation sensor A configured as described above will be described. First, the rectangular wave generated by the rectangular wave generator 14 inside the microcomputer 4 is sent to the excitation wave generator 1. In the excitation wave generating unit 1, the generated rectangular wave is frequency-divided by the frequency dividing circuit 15, and then a sine wave is generated via the LPF 16 and becomes the excitation sine wave input 11 via the buffer amplifier 7.

The excitation sine wave input 11 (sin ωt) is supplied to the excitation coil 10 that is locked to the rotor 6 of the resolver 2 described above. A set of two output coils 8 and 9 that are locked to the stator 6 are arranged 90 degrees out of phase with respect to the rotational direction of the exciting coil 10 that is locked to the rotor 6. When the excitation sine wave input 11 sent from the excitation wave generator 1 is input to the excitation coil 10 arranged in this way, two SIN outputs 12 and COS outputs 13 shown below are obtained from the output coils 8 and 9, respectively. It is done.
SIN = Asinθsinωt
COS = A cos θ sin ωt
Where A: Resolver excitation amplitude
θ: Rotor angle
ω: Excitation frequency.

  Next, the SIN output 12 and the COS output 13 obtained as the output of the resolver 2 are input to the output circuit 3. The output circuit 3 is an amplifier circuit for amplifying the two outputs, and is used before the analog SIN output 12 and COS output 13 obtained by the microcomputer 4 are converted into digital signals.

  The SIN output 12 and the COS output 13 amplified by the output circuit 3 are A / D converted by the A / D converter 18 in the microcomputer 4. The A / D conversion timing is synchronized with the sine wave input 11 by a timer of the microcomputer 4 or the like. That is, since the timing for taking in data for A / D conversion is synchronized with the frequency of the excitation sine wave input 11 described above, sin ωt in the above equation can be regarded as a constant. Then, the A / D conversion values of the SIN output 12 and the COS output are determined by sin θ and cos θ.

  The rotation angle of the motor is calculated by the calculation unit 17 inside the microcomputer 4 based on the thus obtained A / D converted sin θ and cos θ. The internal operation of the microcomputer 4 including the calculation unit 17 is shown in the flowchart shown in FIG. First, when the SIN output 12 and the COS output 13 are inputted into the microcomputer 4, after the initial excitation is performed for a predetermined time in order to stabilize the excitation of the resolver (S1), as described above, the excitation sine wave input 11 is input. A / D conversion is performed by the A / D converter 18 in synchronization with the frequency (S2). Thereafter, AD conversion value voltage adjustment, AD conversion value hysteresis setting, and the like are performed. From the sin θ and cos θ obtained in this way, it is first determined where in the first to fourth quadrants the angle of the rotating shaft of the motor (S3). This determination is made based on the signs of sin θ and cos θ.

  From here, it demonstrates based on FIG. FIG. 4 shows a flowchart when it is determined in the above-described quadrant determination step (S3) that the angle of the rotation shaft of the motor is in the first quadrant. First, it is determined whether or not the obtained sin θ value is 0.707 (θ is 45 degrees) or less (S4). That is, in the range where sin θ is larger than 0.707, the change amount of the sin θ value with respect to the change amount of the θ value becomes large. In this case, the value of θ is calculated with reference to the value of cos θ.

When sin θ is 0.707 or less, after setting the hysteresis of sin θ, the value of θ is set from the table 23 of sin θ and θ (S5). Such a table 22 can be stored in advance in a ROM or the like in the microcomputer 4. Next, in step (S7), the obtained value of θ is transferred to the next process for controlling the vehicle door, trunk lid, and the like.

  As described above, when the value of sin θ is 0.707 or more, the value of cos θ is used. First, after setting the hysteresis of the obtained cos θ, θ is determined based on the normalization table 24 of cos θ vs. θ (S6). The table 24 can also be stored in advance in a ROM or the like inside the microcomputer 4 as described above, and can be referred to as external data. Thereafter, the process proceeds to a step (S7) of transferring the obtained θ information to the next process. In step (S6) in which θ is determined based on the normalization table 24 of cos θ vs. θ, the value of sin θ is obtained from the value of cos θ, and the sin θ and θ table 23 are used to determine the value of sin θ. It is also possible to determine the value of θ (S5).

  Next, a flowchart when it is determined that the angle of the rotation shaft of the motor is in the third quadrant is shown in FIG. Even in the third quadrant, since it is almost the same as the first quadrant described above, the description of the overlapping parts is omitted. Unlike the case of the first quadrant, the values of sin θ and cos θ are negative in the third quadrant. Therefore, a step for obtaining the absolute value is newly inserted (S8). The step of obtaining the absolute value of sin θ (S8a) is inserted before the step of determining whether the value of sin θ is 0.707 (θ is 45 degrees) or less (S4), and the step of obtaining the absolute value of cos θ ( S8b) is inserted before the normalization table search step (S7) of cos θ and θ. Similarly, in the second quadrant or the fourth quadrant, the absolute value is used to set the value of sin θ or cos θ to a positive value, and the same processing is performed. By doing in this way, the data amount of a normalization table can be reduced and the load concerning a table search can be made small.

  Since the drive shaft angle is determined using the normalization table 22 in this way, a large burden is not imposed on the calculation unit 17. Therefore, a high-speed response can be achieved to some extent without using an expensive DSP.

  Further, when the system of the present invention is used for a vehicle door, for example, a slide door for opening and closing a side surface of a vehicle or a back door provided at the rear, a resolution of about 100 can be obtained with an easy configuration. Can be realized at a low price. For example, if the resolution is 100 or more per rotation of the rotary shaft, the door position and the door speed can be detected for each of the 100 divisions, so even if a human body or an object is sandwiched The detection of pinching is performed promptly, and the load of pinching the door is not easily transmitted to the human body or objects, so that a safe door system can be constructed.

FIG. 1 is a block diagram of this embodiment. FIG. 2 is a schematic diagram showing an example of a resolver. FIG. 3 is a flowchart of the first stage of the calculation unit of the rotation sensor of FIG. FIG. 4 is a flowchart of the first quadrant of the second stage of the calculation unit of the rotation sensor of FIG. FIG. 5 is a flowchart of the third quadrant of the second stage of the calculation unit of the rotation sensor of FIG.

Explanation of symbols

S1 initial excitation step S2 A / D conversion step S3 quadrant determination step S4 sin θ ≦ 0.707 step S5 sin θ vs. θ table search step S6 cos θ vs. θ table search step S7 next processing delivery step S8a step for obtaining ABS (sin θ) S8b ABS Step (1) for obtaining (cos θ) Excitation power supply 2 Resolver 3 Output circuit 4 Microcomputer 5 Stator 6 Rotor 7 Buffer amplifier 8 Output coil 9 Output coil 10 Excitation coil 11 Input sine wave 12 SIN output 13 COS output 14 Rectangular wave generator 15 Frequency division Circuit 16 Low-pass filter 17 Calculation unit 18 A / D converter 20 Shaft 21 Calculation unit 22 Table 23 Table (sin θ, θ)
24 tables (cos θ, θ)

Claims (4)

A drive shaft;
A resolver that detects a rotation angle of the drive shaft and outputs a sine wave and a cosine wave voltage by a one-phase sine wave voltage input;
An A / D converter for A / D converting the output of the sine wave and cosine wave voltage;
A calculation unit for calculating the angle of the drive shaft from the output of the A / D converter;
A rectangular wave generator that generates a rectangular wave in synchronization with the A / D converter;
An excitation wave generation unit that generates a sine wave voltage input to the resolver from the rectangular wave,
The A / D converter, the calculation unit, and the rectangular wave generation unit are configured by a microcomputer,
When the calculation unit divides the determined quadrant into two equal parts, and a first step of determining a quadrant of the rotation angle of the drive shaft from the output of the A / D converted sine wave and cosine wave voltage In addition, after passing through a second step of determining which side the rotation angle of the drive shaft is, the rotation sensor calculates the angle of the drive shaft according to the determination result.   The microcomputer includes a storage unit storing a table for searching the drive shaft angle corresponding to the sine wave and cosine wave voltages of the drive shaft in the calculation unit according to the determination result. Item 10. The rotation sensor according to Item 1.   A vehicle moving body comprising: the rotation sensor according to claim 1; a drive motor for driving the drive shaft; a vehicle moving body operated by the drive motor; and a control unit for controlling opening and closing of the vehicle moving body. system.   The vehicle moving body system according to claim 3, wherein the vehicle moving body is one of a slide door provided on a side surface of the vehicle and a back door or a trunk lid provided behind the vehicle.

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