JPS62142213A - Circulation driving type rate gyro - Google Patents

Abstract

PURPOSE:To execute a detection of an inertia angular velocity of a high performance, which scarcely causes an error response against an input except an inertia angular velocity, by providing a fine adjustment mechanism for executing a fine adjustment in the direction of a detection sensitivity, in case of converting a force working on a mass element to an electric signal. CONSTITUTION:A driving direction of a simple harmonic motion is determined by a thickness direction of a driving use piezoelectric bimorph element 2, and also a thickness direction of a detection use piezoelectric element 1, therefore, in order to prevent an error response caused by a driving inertia force, an orthogonality of a junction of the elements 1, 2 becomes a key point. Also, joint members 3A, 3B are joined to the elements 1, 2, respectively. Also, the member 3A is provided with a working part which has been brought to tooth profile working, and a joint 3C is an adjusting screw which is meshed to said part and executes a fine adjustment to a joint angle of the members 3A, 3B. Also, it is fixed to 3B so as not to be shifted in its lengthwise direction, by a fixing spring 3D. By operating a rate gyro which has been constituted in this way, and adjusting the joint 3C so that an output of the element 1 becomes zero without inputting an inertia angular velocity, an error response caused by mixing a driving inertia force component into a deflection detecting signal is eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a rate gyro for detecting the inertial angular velocity of an object, and more particularly to a rate gyro driven by vibration or rotation.

2. Description of the Related Art There are various devices that measure the rotation rate with respect to an inertial system, which is generally referred to as the fit angular velocity.
gular rate 5 sensor or Ar+gu
lar ve-1oCity 5 sensor), rate gyro, angular velocity detector (8 ngular rat
It is called by various names such as e-sensing device (e-sensing device). Hereinafter, the term "rate gyro" will be used in the present invention.

Conventionally, various rate gyros have been proposed, but the operating principles common to all of them are: 1) The mass element is forcibly driven within the measured coordinate system, and 2) By that drive, the measured coordinate system 3) Detecting the force acting on the mass element, and detecting the deviation according to the Coriolis force from the displacement detection signal. It can be said that the components are extracted and subjected to No. 3 processing according to the generation mechanism of Coriolis force to obtain an output proportional to the inertial angular velocity.

By the way, the various rate gyros that have been proposed so far are characterized by their drive form (simple vibration drive, swing drive, rotational drive, linear drive), drive method (those using electromagnetic action, mass elements to which the Coriolis force is applied (e.g. cantilevers, tuning forks, vibrating parts of strings, rotor components, emitted gas, etc.)
There are also methods for detecting the force acting on the mass element (methods using electromagnetic action, methods using piezoelectric effect, methods using cantilevers, methods using torque springs, etc.), and the method of classification changes depending on the point of view. come.

The rate gyro device targeted by the present invention focuses on the drive method among the above-mentioned classification elements, and belongs to a cyclic drive type rate gyro such as a simple harmonic drive or a swing drive that is a two-dimensional combination thereof.

This circulation-driven rate gyro uses differences in the other factors mentioned above, such as vibrating a cantilever beam using electromagnetic force.
When an inertial angular velocity is input, a Coriolis force is applied to the tip and the resulting deviation is electromagnetically detected, or a piezoelectric effect is used for excitation, detection, or both ( Both are US Patent No. 2544646
(No.), and one that picks up the Coriolis force acting on a cantilever-shaped piezoelectric element by rotating it (US Pat. No. 2,716,893).

Here, the Coriolis force is proportional to the vector product of the human power inertial angular velocity and the drive speed, so in the above two cases as well as in other cases, if it is a circulation drive type sea 1-gyro, the above mass The Coriolis force acting on the element acts in a direction perpendicular to both the instantaneous driving speed and the human inertial angular velocity, and its magnitude depends on the driving speed (or its desired directional component)
changes alternately in synchronization with the changes in This is significantly different from a rotation-driven rate gyro, which converts the Coriolis force into DC torque by spatially integrating it).

Therefore, when configuring a circulation drive type rate gyro, when converting the force acting on the mass element into a deflection detection signal, the sensitivity direction is always the direction of the required component of the inertial angular velocity and the drive speed (in the case of swing drive, the component of interest) The driving speed (
It is common to perform synchronous detection using the component of interest) as a reference phase.

Problems to be Solved by the Invention According to such a configuration, it is possible to realize a device that can respond to human inertial angular velocity. However, the operation of the rate gyro is to respond to human inertia angular velocity, and at the same time,
It is equally important that it does not respond to inputs of other physical quantities (for example, gravity, forces such as inertia due to translational motion, temperature, humidity, etc.).

The first possible cause of such an error response is that a force outside the Coriolis force acts on the mass element.
This is because an error component is mixed into the deviation detection signal.

Forces outside the Coriolis force that act on the lff1 element include gravity, an inertial force as a reaction force based on the translational acceleration of the measured coordinate system with respect to the inertial frame, and an inertial force as a reaction force based on the acceleration associated with circulation drive (drive (inertial force), centrifugal force accompanying rotational movement, etc., but how these appear as error responses differs depending on the configuration of the rate gyro.

For example, in a simple harmonic drive type rate gyro, the direction of sensitivity when converting the force acting on the mass element into a deflection detection signal does not change over time with respect to the drive system (measured coordinate system), so it is The component mixed into the deflection detection signal due to acceleration has no causal relationship with the drive and can be almost completely separated from the component due to Coriolis force, so it hardly appears in the final error response. On the other hand, the drive inertia force (reaction force based on acceleration associated with simple harmonic motion) has a relatively large absolute value, and when it appears in the deviation detection signal, it is essentially the same frequency as the drive frequency, so it can be discriminated by frequency. Even a slight error in synchronous detection causes an extremely large offset, and fluctuations in circuit constants due to changes in temperature, humidity, etc. can cause drift, and even cause alternating current ripple.

The amplitude of this driving inertial force is 1/2ω (ω is the driving angular frequency) when converted into the inertial angular velocity required to generate a Coriolis force of the same amplitude, but this value is not practical for a rate gyro. Drive frequency, several hundred to several kHz (several blades to several hundred thousand”/5ec at angular frequency ω)
When considering the minimum resolution normally required for this type of device, 0.01 to 0.1°/sec % and the Guinamiso clean range ± 100°/sec,
You can see how big the value is.

On the other hand, in a swing-driven rate gyro that combines simple harmonic motion in two dimensions, the drive inertia becomes centrifugal force against the mass element and is converted to DC, so it is mixed into the deviation detection signal. is not a problem because it can be clearly separated from the component caused by the Coriolis force.

However, if there is a deviation between the direction of the rotation axis and the above-mentioned sensitivity direction, the sensitivity direction changes in synchronization with the drive system (coordinate system to be measured), so gravity, which was not a problem with the simple harmonic drive type, A component due to disturbance acceleration such as inertial force appears in the deviation detection signal in a form modulated by the drive frequency, and becomes a major error factor.

For example, if we convert gravity into the input inertial angular velocity required to generate the same Coriolis force as we did for the drive inertia force in the explanation of the simple harmonic drive type, then G/(
2rω) (here, G is the gravitational acceleration, r is the turning radius, and ω is the drive angular frequency).

This value is the turning drive angular velocity that is practical for the device, several thousand rpm (several hundred rad/5ec at angular frequency ω), turning radius r, several to dozens of fins, and gravitational acceleration G = 9.8 m/s.
Considering s, it is several thousand to several hundred'/sec, which is a much smaller value compared to the drive acceleration in a simple harmonic drive type, but if it is mixed into the deviation detection signal, it will cause the phase to be orthogonal as in a simple harmonic drive type. Since there is no guarantee of accuracy, removal by synchronous detection cannot be expected, and considering the accuracy required for the rate gyro mentioned above, this is still a large error factor.

In order to prevent these drive and synchronization error components from being mixed into the deviation detection signal, it is necessary to set the sensitivity direction setting accuracy (*orthogonality with the drive direction for vibration drive types, and in the direction of the rotation axis for swing drive types). There is no other way but to increase the consistency with

However, in the conventional cyclic drive type rate gyro, the setting accuracy simply relies on the processing accuracy and assembly accuracy of the parts, and therefore, the specified accuracy is not obtained, and the above-mentioned mechanism causes an error response, and the rate gyro At present, sufficient performance has not been achieved.

An object of the present invention is to provide a high-performance rate gyro without such error response.

Means for Solving the Problems The present invention solves the above problems by providing a fine adjustment mechanism for finely adjusting the direction of detection sensitivity when converting the force acting on the mass element into an electric signal. The goal is to achieve the goals of

According to the above-described means, it is possible to prevent drive and synchronization error components from being mixed into the deviation detection signal, and it is possible to achieve high performance with less error response to other rostral stars other than inertial angular velocity. characteristics can be obtained.

Embodiment Hereinafter, an embodiment of the present invention will be described with reference to the drawings, taking as an example a cantilever-shaped simple harmonic drive type rate gyro using piezoelectric bimorph elements for driving and sensing.

FIG. 1 shows the basic configuration of a simple harmonic drive type rate gyro taken as an example in this embodiment.

In Figure 1, 1 should cause the Coriolis force to act.
It is a detection piezoelectric bimorph element that constitutes the tffi element and detects the force acting on itself and generates an electric output (deviation detection signal) in accordance with it. It is joined.

Reference numeral 2 denotes a drive piezoelectric bimorph element for imparting simple harmonic motion to the detection piezoelectric bimorph element, and is supported at one end by a base 4.

5 is a drive circuit for exciting the cantilever constituted by the detection piezoelectric element 1, the drive piezoelectric element 2, and the joint 3 at its resonant frequency; This is an oscillation circuit that uses a frequency selection element.

Reference numeral 6 denotes a signal processing circuit for receiving the deviation detection signal 1' from the piezoelectric bimorph element for detection and outputting an inertial angular velocity signal, and is composed of a frequency discriminator, a synchronous detector, and the like.

With the above configuration, when the cantilever beam is excited and an inertial angular velocity is manually applied to its support pair, the Coriolis force acts on the detection bimorph element and the inertial angular velocity is detected.

Here, the driving direction of the simple harmonic motion is determined by the thickness direction of the drive piezoelectric bimorph element 2, and the sensitivity direction of the detection piezoelectric element is determined by the thickness direction of the detection piezoelectric element 1. In order to prevent the error response caused by the drive inertia force described in detail in the above-mentioned problem, the key point is the orthogonality of the junction between the detection piezoelectric bimorph element 1 and the drive piezoelectric bimorph element 2.

FIG. 2 shows a fine adjustment mechanism for finely adjusting the orthogonality,
FIG. 2 is an external view showing the configuration of a joint in an embodiment of the rate gyro of the present invention, which makes it possible to improve its accuracy.

In FIG. 2, 3A and 3B are joint members that are joined to the detection piezoelectric bimorph element 1 and the driving piezoelectric bimorph element 2, respectively, and 3A is provided with a tooth-shaped processed portion 3a.

3C meshes with the toothed part 3a of said 3A, and 3A and 3B
This is an adjustment screw for finely adjusting the joining angle of the joint angle, and is fixed to 3B by a fixing spring 3D so as not to shift in the length direction.

FIG. 3 shows a side view of a cantilever rate gyro using a joint configured as described above.

By operating the rate gyro configured as above and adjusting the adjustment screw 3C so that the output of the detection bimorph element becomes zero when no inertial angular velocity is input, the deviation detection signal of the driving inertial force component is obtained. It is possible to prevent the contamination of the gyro, and to realize a rate gyro without error response caused by the contamination.

Although one embodiment has been described above, taking as an example a simple harmonic drive type rate gyro, in particular a cantilever-shaped rate gyro using a piezoelectric bimorph element, the present invention is of course not limited to this. It is also possible to use other fine adjustment methods for cantilever rate gyros using piezoelectric bimorph elements, and similar or different methods for other simple harmonic drive type and swing drive type rate gyros. The same effect can be obtained by providing a fine adjustment mechanism in the sensitivity direction when generating the deviation detection signal (However, in the case of a rotation drive type rate gyro, since the drive is two-dimensional, the sensitivity direction fine adjustment mechanisms are also required in each of the two directions)
.

Effects of the Invention As is clear from the detailed explanation above, the circulation drive type rate gyro of the present invention is provided with a fine adjustment mechanism that finely adjusts the direction of detection sensitivity when converting the force acting on the mass element into an electric signal. By doing so, it is possible to prevent drive and synchronization error components from being mixed into the deviation detection signal, and it is possible to detect high-performance inertial angular velocity with less error response to physical quantity inputs other than inertial angular velocity. .

[Brief explanation of drawings]

FIG. 1 is a perspective view showing the basic configuration of an embodiment of the present invention, FIG. 2 is a perspective view showing the configuration of a fine adjustment mechanism in the sensitivity direction in an embodiment of the present invention, and FIG. FIG. 2 is a side view showing one embodiment of the invention. ■・・・Piezoelectric bimorph element for detection, 2...
...Piezoelectric bimorph element for driving, 3...Joint, 3A. 3B...Joint member, 3a...Tooth type processing part, 3C...Adjustment screw, 3D...
・・Fixing springs, 4・・Base, 5・・・・
Drive circuit, 6... Signal processing circuit. Name of agent: Patent attorney Toshio Nakao (1 person) Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] a cyclically driven mass element; a deflection detection signal source that detects a force acting on the mass element and outputs an electrical signal;
A circulation drive type rate gyro comprising: a fine adjustment mechanism that finely adjusts the direction of detection sensitivity when converting the force acting on the mass element into an electric signal.