JPH01224672A - angular accelerometer - Google Patents

Abstract

PURPOSE:To obtain accurate angular acceleration with good frequency characteristics without being affected by temperature and noise by differentiating and integrating the voltages of two power generating coils which are induced at different timing by the rotation of a rotor according to the rotation angle position of the rotor. CONSTITUTION:A rotary encoder (RE) 1 detects the rotation angle theta position of the rotor 4a of a rotating machine. A power generator 2 is equipped with two power generating coils 2a and 2b, which are arranged at fixed positions facing a magnet 2c fitted on the side of the rotor 4a while shifting by 90 deg. in the rotating direction of the magnet 2c. The voltages Va and Vb which are induced at the power generating coils 2a and 2b are Va=omegacostheta and Vb=omegasintheta, where omega is the rotating speed of the rotor 4a. The rotation angle position thetaof the rotor 4a which is detected by the RE 1 and the induced voltages Va and Vb of the power generating coils 2a and 2b are inputted to an arithmetic circuit 3. The arithmetic circuit 3 substitutes those values in a=costheta.dVa/dt+ sintheta.dVb/dt to calculate the angular acceleration (a).

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to an angular accelerometer that detects the angular acceleration of a rotor.

[Prior Art] Conventionally, there is control of angular velocity and angular acceleration as control of rotating machines.

There are various types of angular velocity meters that detect the angular velocity of a rotating machine, such as a generator type, a magnetic type, a photoelectric type, and a centrifugal type. For example, in the case of a generator type, the rotor is Measure angular velocity.

E=-dφ/dt On the other hand, an angular accelerometer that detects the angular acceleration of a rotating machine measures the torsion of the rotor of the rotating machine using a strain gauge.
The angular acceleration of the rotor was determined from the twist.

[Problems to be Solved by the Invention] Conventional angular accelerometers for rotating machines are highly temperature dependent, sensitive to noise, and sensitive to low frequencies because they are strain gauges that measure the torsion of the rotor. Responsiveness was poor. Therefore, it is difficult to accurately control the angular acceleration of a rotating machine using such an angular accelerometer.

This invention solves these problems.

Means for Solving Lesson 5] The angular accelerometer of the present invention includes a rotational position detector that detects the rotational angular position of the rotor, and two power generation coils that are excited with voltages at different timings by the rotation of the rotor. and the rotational angular position θ of the rotor detected by the rotational position detector.
and the voltages Va, Vb excited in the two generating coils.
a”cosθ・dV a /dt +sinθ−dVb
It is characterized by comprising an arithmetic circuit that calculates the angular acceleration a of the rotor by substituting it into the formula /dt.

Further, the angular accelerometer of the present invention includes: a rotational position detector that detects the rotational angular position of the rotor; two power generation coils that are excited with voltages at different timings due to the rotation of the rotor; and the rotational position detector. Rotation angle position θ of rotor to be detected
and the voltages Va, Vb excited in the two generating coils.
a = d/dt (V a - cos θ + V b -si
and an arithmetic circuit that calculates the angular acceleration a of the rotor by substituting it into the equation nθ).

Further, the angular accelerometer of the present invention includes an angular velocity detector that detects the angular velocity of the rotor, and an angular velocity ω of the rotor detected by the angular velocity detector as follows: a = 1/2 ω ・d/dt (ω'
) for calculating the angular acceleration a of the rotor.

[Operation] The angular accelerometer of the present invention has the rotational angular position θ of the rotor;
2 induced at different timings due to the rotation of the rotor
Accurate angular acceleration a is determined by differentiating and integrating the voltages Va and Vb of the two power generating coils. Alternatively, the accurate angular acceleration a is obtained by calculating the angular velocity ω of the rotor.

[Example] Hereinafter, one embodiment of the present invention will be described based on the drawings.

The angular accelerometer of this embodiment is composed of a rotary encoder (rotational position detector) 1, a generator 2, and an arithmetic circuit 3, and is incorporated into the control system of a rotating machine (motor) 4 (Fig. reference).

The rotary encoder l is connected to the drive shaft of the rotating machine 4 (
The rotation angle position θ of the rotor 4a is detected.

The generator 2 includes two generator coils 2a and 2b whose voltage is excited by the rotation of the drive shaft 4a of the rotary machine 4. These power generation coils 2a, 2b are arranged so that voltages are excited at different timings. In the case of this embodiment, as shown in FIG.
Attach a magnet 2c to the side, and place it at a fixed position facing the magnet 2c at 90° in the direction of rotation of the magnet 2c.
It is placed out of alignment. Therefore, the generating coil 2a,
An electromotive voltage Va induced in 2b.

vb is expressed by the following formulas (1) and (2).

Va=ωaosθ (1) Vb=ω
sin θ −・−・(2>ω: Drive shaft 4a
Rotation speed θ: Rotation angle position of drive shaft 4a Rotary encoder! The rotation angle position θ of the drive shaft 3a detected by
, Vb are input to the arithmetic circuit 3. The arithmetic circuit 3 calculates the rotation angle position θ and the electromotive force Vu, vb using the following equations (3) and (4
) to calculate the angular velocity ω and angular acceleration a of the drive shaft 3a.

ω=V a cosθ+Vbsinθ...
...(3) a=cosθ・dV a /dt +s
inθ-dVb/dt...(4) "Proof of the above equation (3)" The following equation (5), which multiplies both sides of equation (1) by cos θ, and (2
) The above equation (3) can be found by adding the below equation (6), which is obtained by multiplying both sides of the equation by sin θ.

V a cosθ=ωcO32θ ,・,・(5)V
bsinθ=ω5in2θ −・・−(6)(5)
Formula + (6) Formula V a cosθ+Vbsinθ−ω(CO5”θ+s
in'θ)=ω "Proof of the above equation (4)" Differentiate equation (3) with respect to time t.

a=dω/dt = cosθ・dV a/dt−sinθ・dθ/dt
-Va+sin θ ・dV b /dt +c
os θ −d θ /dmu ・V bVa in this equation,
By replacing Vb with the above equations (1) and (2), the second term and the fourth term disappear, and the above equation (4) is obtained.

The angular velocity ω of the drive shaft 3a determined by the calculation circuit 3
and angular acceleration a are manually input to the motor drive unit 5 and the display section 6. The motor drive unit 5 controls the angular velocity and angular acceleration of the rotating machine 3 based on the angular velocity ω and the angular acceleration a, and the display unit 6 displays the angular velocity ω and the angular acceleration a digitally or in analog form in a rod format.

In this way, the angular acceleration Y is determined by the rotational angular position θ from the rotational position detector I and the generator coil 2a.

2 b +,: The induced voltages Va and Vb are calculated by the calculation circuit 3.
The angular acceleration a is obtained by performing differentiation and integration processing at , and the display section 6 displays the angular acceleration a.

Note that the arithmetic circuit 3 can be incorporated into, for example, a semiconductor IC (gate array IC), thereby realizing a highly reliable angular accelerometer with a single chip at low cost. Alternatively, the magnet 2c may be placed at a fixed position to rotate the power generation coils 2a, 2b. In short, any configuration is sufficient as long as voltages are induced in the generator coils 2a, 2b at shifted timings by the rotation of the drive shaft 4a.

Further, as another embodiment of the present invention, the arithmetic circuit 3 may calculate the angular acceleration a using the following equation (7) instead of the above equation (4).

a = d/dt (V a II cos θ + Vb・Si
nθ)...(7) The above equation (7) is a modification of equation (4), and this (
7) When arithmetic processing is performed using a formula, it becomes a simple differential form, which simplifies and speeds up the arithmetic processing.Additionally, there are parts that are canceled in the addition process of differential moe, resulting in fewer digits being lost. .

Furthermore, as another embodiment of the present invention, it is also possible to use an arithmetic circuit 3 that squares the angular velocity of the rotor and performs differential processing.

In this case, an angular velocity detector that detects the angular velocity of the rotor and an arithmetic circuit 3 that calculates the angular acceleration a by substituting the angular velocity ω of the rotor detected by the angular velocity detector into the following equation (8) are used. The angular velocity ω is obtained from a tacho generator or a rotary encoder.

a=1/2cc+・d/dt (ω') --(
8) When the calculation process is performed using the above equation (8), the number of calculations is small and there is no trigonometric function, so the calculation process can be simplified and speeded up, and the memory capacity can be reduced. Furthermore, since the angular velocity ω can be squared and the high frequency components can be removed by a filter, noise is reduced.

FIG. 3 is a diagram showing a concrete implementation result of the present invention.

In this specific example, a 70W glue, a tacho generator (equivalent to "generator 2") and a rotary encoder (equivalent to "rotation/position detector!") are mounted on the shaft of a C-branchless motor.
connected. The motor drive unit (corresponding to "motor drive unit 5") includes an arithmetic circuit ("
A digital display device (corresponding to the "display section 6") was connected to the arithmetic circuit.

Then, the angular velocity ω and angular acceleration a obtained by the arithmetic circuit were fed back to the motor drive unit, thereby constructing a control system for the angular velocity and angular acceleration of the motor.

Such a system controls the angular velocity and angular acceleration of the motor, and as shown in A in the figure, the speed is 0.4 in 3 seconds.
Control was carried out to start up to N, m, and control to start up to 0.5 N, m at I sec as shown in B in the figure. In both cases, smooth control was achieved.

[Effects] As explained above, the angular accelerometer of the present invention has the advantage that the voltages Va and Vb of the two power generating coils induced at different timings due to the rotational angular position θ of the rotor and the rotation of the rotor are
Since the angular acceleration a is obtained by performing differentiation and integration processing, it is less susceptible to temperature and noise effects and has better frequency characteristics than a conventional angular accelerometer using a strain gauge.

Further, when the angular velocity is squared and differentiated, it is possible to reduce noise and obtain accurate angular acceleration 1.

Further, the angular accelerometer of the present invention can be used for controlling various types of machinery such as the movable parts of robots using rotating machines, and has an extremely wide range of applications. For example, it is also possible to follow-up control of the rotational force in response to changes in the rotational force in a lathe or the like.

[Brief explanation of the drawing]

The drawings are diagrams for explaining the invention in detail.
The figure is a block configuration diagram, FIG. 2 is an explanatory diagram of a power generation coil, and FIG. 3 is a diagram for explaining specific implementation results. ! ...Rotary encoder (rotary position detector), 2... Generator, 2a, 2b...
Generator coil, 2c... Magnet, 3...
...Arithmetic circuit, 4...Rotating machine (motor), 4a...II shaft (rotor), 5...
...Motor drive unit, 6...Display section.

Claims (1)

[Claims] (1) A rotational position detector that detects the rotational angular position of the rotor; two power generation coils whose voltages are excited at staggered timings due to the rotation of the rotor; and the rotational angular position of the rotor that is detected by the rotational position detector. θ
and the voltages Va, Vb excited in the two generating coils.
a=cosθ・dVa/dt+sinθ・dVb/dt
(2) a rotational position detector for detecting the rotational angular position of the rotor; Two generator coils whose voltage is excited at the right timing, and the rotational angular position θ of the rotor detected by the rotational position detector.
and the voltages Va, Vb excited in the two generating coils.
(3) Angular velocity detection for detecting the angular velocity of the rotor and an arithmetic circuit that calculates the angular acceleration a of the rotor by substituting the angular velocity ω of the rotor detected by the angular velocity detector into the formula a=1/2ω・d/dt(ω＾2). angular accelerometer