JPS62237302A - Rotational position detector for rotary oscillatory actuator - Google Patents

Abstract

PURPOSE:To speed up the response of a rotary oscillatory actuator to a rotation control signal by providing a magnet part at an end surface of an output shaft and a magnetic sensor at the opposite position of the end surface. CONSTITUTION:This device consists of a rotational force generation part 1 which controls the device electrically, the output shaft 2, a rotational position detection part 3, the magnet part 4 provided on the end surface 2a of the output shaft 2, and the electric sensor 5 provided at the opposite position. The sensor 5 utilizes ferromagnetic magneto-resistance effect and a pattern of ferromagnetic metal is provided on the opposite surface of the magnet part 4, so that the sensor operates as a magnetic flux response type sensor. Then a reference position is set when the border line A of the magnet part 4 is positioned as shown by a double dotted chain line for the sensor 5 and a bias voltage is impressed to obtain a sinewave output voltage. This output voltage varies almost linearly within a range shown by a solid line and an angle of rotating and an output voltage vary linearly. Therefore, the angle of rotation of the output shaft 2 is detected from the output voltage.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a rotational position detection device for a rotary swing actuator for detecting the rotational position of an output shaft.

[Summary of the Invention] The present invention provides a rotational position detection device for a rotary oscillating actuator that detects the rotational position of an output shaft. By providing this, the inertia of the output shaft is reduced and the response of the rotary swing actuator to the rotation control signal can be increased.

[Prior Art] For example, a galvano scanner reflects a laser beam on a mirror and irradiates the photosensitive area of a printer with the reflected light. By changing the rotational position of the mirror, the laser beam can be directed to a desired position on the photosensitive area. irradiate. In order to regulate the rotational position of the mirror, a rotational position detection device is provided on the output shaft of the rotary swing actuator that rotates the mirror.

In such a conventional rotational position detection device, as shown in FIG. 6, a rotor 21 is provided on the circumferential surface of the output shaft 2 so as to protrude in the radial direction. The four stators 22 have an arcuate shape and are disposed on the circumference of the output shaft 2 to form a substantially circular shape as a whole. The four stators 22 are connected to each other at opposing positions, and the four stators 22 and the rotor 21 constitute two capacitors.

When the output shaft 2 rotates and comes to the position shown by the two-dot chain line in FIG. The capacity of the capacitor is also different. Therefore, since the rotation angle of the output shaft 2 is proportional to the capacitance of the capacitor, the rotation angle of the output shaft 2 is detected by comparing the capacitances of both capacitors (U.S. Pat.
42゜144).

[Problems to be Solved by the Invention] However, in the above-mentioned rotational position detection device, since the rotor 21 that protrudes in the radial direction of the output shaft 2 is attached, the inertia of the output shaft 2 becomes large and the rotation control signal is The rotary swing actuator had a drawback of poor response.

In particular, the output shaft 2 for mirror rotation used in a galvano scanner has a vibration period of 30 hertz or more, for example, and is required to have a fast response.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a rotational position detection device for a rotary and oscillating actuator that can increase the responsiveness of a rotary and oscillating actuator to a rotational control signal.

[Means for Solving the Problems] Accordingly, the configuration of the present invention for achieving the above-mentioned object is such that the end face of the output shaft of the electrically controllable rotational force generating section and the opposing position of this end face, It is characterized in that a magnet section is provided on one side, and a magnetic sensor that outputs an output according to a change in the magnetic field direction of the magnet section is provided on the other side.

[Operation] Therefore, even if the output shaft rotates, since the magnet portion or the magnetic sensor is provided on the end face of the output shaft, the rotational torque of the portion that does not contribute to torque generation is small, and the inertia of the output shaft is small.

[Example] Embodiments of the present invention will be described below based on the drawings.

In FIG. 1, an electrically controllable rotational force generating section 1 is constituted by a coreless motor in this embodiment. This motor has an output shaft 2 protruding from both end faces, a mirror (not shown) that reflects laser light at one end, and a rotational position detection device 3 at the other end. .

This rotational position detecting device 3 has a magnet part 4 provided on one end face 2a of the output shaft 2 and a position opposite to this end face 2a, and a magnet part 4 provided on the other hand that responds to a change in the direction of the magnetic field. It is composed of a magnetic sensor 5 that outputs an output. In this embodiment, a magnet part 4 is provided on the end surface 2a of the output shaft 2, and a magnetic sensor 5 is provided at a position opposite to the magnet part 4.

The magnet section 4 has a cylindrical shape and has two poles, an S pole and an N pole, on its upper surface with a boundary line A interposed therebetween.

The magnetic sensor 5, as shown in detail in FIG.
It utilizes the ferromagnetic magnetoresistance effect, and a ferromagnetic metal pattern is provided on the opposing surface of the magnet portion 4, so that it operates as a magnetic flux responsive sensor.

When the magnetic sensor 5 is set to the basic position (rotation angle 0°) when the boundary line of the magnet portion 4 is at the position indicated by the two-dot chain line in FIG. A sinusoidal output voltage as shown is obtained. This output voltage changes almost linearly in the range shown by the solid line in Figure 3.
Rotation angle and output voltage are linearly proportional. Since it is linearly proportional to this, the rotation angle of the output shaft 2 can be known from the output voltage.

As shown in FIGS. 4 and 5, the drive control circuit of the rotational force generating section 1 includes an amplifier circuit 6 that amplifies the output voltage of the magnetic sensor 5.

The amplifier circuit 6 differentially amplifies both output signals of the magnetic sensor 5 and outputs an angle signal Vo, and has two operational amplifiers 7.8, and has resistors R, , R, at their input terminals. Output terminals a and b of the magnetic sensor 5 are connected through the magnetic sensor 5, respectively. The output terminals of both operational amplifiers 7.8 are connected to one input terminal of each through resistors Ra and R4, and each operational amplifier 7.8 amplifies the respective output voltage of the magnetic sensor 5.

A common connection point between the output terminal of one operational amplifier 7 and resistor R8 is connected to one input terminal of operational amplifier 9 via resistor R5. The output terminal of the other operational amplifier 8 and the resistor R
A common connection point between the operational amplifier 9 and the resistor R0 is connected to the tenth input terminal of the operational amplifier 9 via a resistor R6, and a common connection point between the tenth input terminal of the operational amplifier 9 and the resistor R0 is grounded through a resistor R1.

The output terminal of this operational amplifier 9 is subjected to negative feedback to one input terminal via a resistor R, and the difference between the two input voltages is amplified. The output voltage of the operational amplifier 9 is output to the differentiator circuit 1q and also to the adder circuit 11.

Note that R8 is a resistor for adjusting the reference value of both operational amplifiers 7.8.

The differentiating circuit 10 converts the angle signal Vθ, which is the output signal of the amplifier circuit 6, into an angular velocity signal Vw.The output terminal of the operational amplifier 9 is connected to one input terminal of the operational amplifier 12 via a capacitor C3, and the operational amplifier The 12 input terminals are grounded.

The output terminal of this operational amplifier 12 is connected to a common connection point between one input terminal of the operational amplifier 12 and the capacitor C1 via a series circuit of a resistor RIo and a variable resistor R11, and this operational amplifier 12 differentiates the input voltage. Outputs a signal (angular velocity signal).

Further, a capacitor C2 is interposed between the output terminal and one input terminal of the operational amplifier 12 to form a band pass filter to cut signals exceeding a predetermined value.

The output terminal of the operational amplifier 12 is connected to a resistor RI! And variable resistance! Se1. It is connected to one input terminal of the operational amplifier 13 via a series circuit with.

This operational amplifier 13 has one input terminal grounded and an output terminal connected to one input terminal via a resistor R14 to amplify the output signal of the operational amplifier 12.

The adder circuit 11 adds the input signal Vi (negative value), the angle signal Ve (negative value), and the angular velocity signal Vw (positive value) to form the input signal Vi, the angle signal We, and the angular velocity signal Yw. It outputs the difference, and is configured to feed back the angular velocity signal Vw together with the angle signal We so that the rotational speed of the output shaft 2 is almost constant.

The adder circuit 11 includes an operational amplifier 14. The output terminal of the operational amplifier 9 is connected to one input terminal of the operational amplifier 14 through a resistor RI5, and the output terminal of the operational amplifier 13 is connected to one input terminal of the operational amplifier 14 through a resistor R+.
The input power is amplified by the operational amplifier 15 via a,
The output terminal of this operational amplifier 15 is connected via a resistor R17,
each connected. The child terminal of this operational amplifier 14 is grounded via the resistor R111, and the output terminal is connected to the resistor R111.
It is connected to one input terminal via 18.

The drive circuit 16 controls the rotation speed of the motor, forwards and reverses, etc. according to the output signal of the adder circuit 11, and the output terminal of the operational amplifier 14 is connected to the input terminal of the operational amplifier 17.

One input terminal of this operational amplifier 17 is grounded through a series circuit of a motor coil L and a resistor of 1° to 1°, and its output terminal is connected to the first and second Darlington circuits 18 and 19.

In the first Darlington circuit 18, the base terminal of the transistor Tr+ is connected to the output terminal of the operational amplifier 17 via the diode D, and the collector terminal is connected to an external power supply (for example, +15V
) are connected to each other. Further, a resistor R2l is interposed between the base terminal and collector terminal of this transistor Trt, and the emitter terminal is connected to the base terminal of the transistor Try.

This transistor Trt has a collector terminal connected to an external power supply (
For example, +15V), and the emitter terminal is connected to the resistor R0.
One input terminal of the operational amplifier 17 and the motor coil L
connected to a common connection point with

In the second Darlington circuit 19, the base terminal of the transistor Trs is connected to the output terminal of the operational amplifier 17 via a series circuit of diodes D, D, and the collector terminal is connected to an external power supply (for example, -15V). . Further, a resistor R23 is interposed between the base terminal and collector terminal of this transistor Tr+, and the emitter terminal is connected to the base terminal of the transistor Tr.

This transistor Tr4 has a collector terminal connected to an external power supply (
For example, the emitter terminal is connected to the resistor 11
It is connected to a common connection point between one input terminal of the operational amplifier 17 and the motor coil L via the ffia.

Therefore, the first Darlington circuit 18 and the second Darlington circuit 19 are activated by the output voltage of the operational amplifier 17, and the first Darlington circuit 18 is connected to the motor coil.
Therefore, a current tends to flow in the direction shown by the solid line in FIG. 5 and corresponding to the difference between the output voltage of the operational amplifier 17 and the external power supply (for example, +15 cm). Furthermore, a current will flow through the motor coil in the direction shown by the broken line in FIG. shall be. Therefore, the current actually flows through the motor coil in the direction of the larger current and by the subtracted amount.

For example, when the absolute values of the input signal Vi and the angle signal Ve are equal (at this time, the angular velocity signal Vw becomes 0), the output voltage of the operational amplifier 17 becomes 0, and the second and second Darlington circuits 18, 19 Both currents flowing to the motor coil cancel each other out, and the 7ri current does not flow.

In the above tank configuration, when an input voltage corresponding to a desired rotation angle is applied, the motor serving as the torque generating section I is driven by the drive control circuit, and the output shaft 2 is rotated at a substantially constant speed to the desired rotation angle.

When the output shaft 2 rotates, the output shaft 2 has an end surface 2a.
A magnet part 4 is fixed to the magnet part 4, and the magnet part 4, which does not contribute to the generation of torque, rotates in the same way. However, since it is provided on the end surface 2a of the output shaft 2 and the rotational torque is small, the inertia is also small and the response to the rotation control signal is fast.

[Effects of the Invention] As described above, according to the present invention, the inertia of the output shaft can be reduced because a magnet portion is provided on one side and a magnetic sensor is provided on the other side of the end face of the output shaft and the opposing face of this end face. This has the effect of increasing the responsiveness of the rotary swing actuator to the rotation control signal.

[Brief explanation of drawings]

1 to 5 show embodiments of the present invention, in which FIG. 1 is a perspective view of the rotational position detection device, FIG. 2 is a bottom view of the magnetic sensor, FIG. 3 is an output waveform diagram of the magnetic sensor, and FIG. FIG. 4 is a block diagram of the drive control circuit, FIG. 5 is a drive control circuit diagram, and FIG. 6 is a perspective view of a conventional rotational position detection device. ■... Rotational force generating section, 2... Output shaft, 2a... End face of output shaft, 3... Rotational position detection device, 4... Magnet part, 5... Magnetic sensor. 1---rfIJ Wholesaler↑Reflection hard soil AL inspection diagram Figure 1 Calculate pumping soil 77 Liquid form diagram Figure 3 Intermediate movement system field rotation flow 1. , Figure 4 Bali 4 country f cho rK, lin 2 Lz fogging device dotsu perspective β
Mouth (Conventional f IJ) Figure 6

Claims (1)

[Claims] A magnet section is provided on one end of the output shaft of the electrically controllable rotational force generating section and a position opposite this end surface, and a magnetic sensor that outputs an output according to a change in the direction of the magnetic field of this magnet section is provided on the other side. A rotational position detection device for a rotary swing actuator, characterized in that: