JPS62239010A - Circulation driving type rate gyro - Google Patents

Abstract

PURPOSE:To separate a component corresponding to a Coliolis force and a component corresponding to a disturbing inertial force with high accuracy by weighting and adding deviation detection signals obtained by detecting independently forces operating on a couple of mass elements which are driven symmetrically. CONSTITUTION:The piezoelectric elements 1a and 1b are driven cyclically in the opposite directions to make the Coliolis force operate, and detect the forces operating on them to generate the deviation detection signals 1a' and 1b'. The signals 1a' and 1b' contain components corresponding to inertial forces, disturbing inertial forces, etc., accompanying the driving. Preamplifiers 2a and 2b convert the signals 1a' and 1b' into low-impedance voltage signals 2a' and 2b'. An adder 4 weight and adds the signals 2a' and 2b'. A signal processing circuit 3 extracts and processes the component corresponding to the Coliolis force from the output signal of the adder 4 to generate an output proportional to an input angular velocity. Thus, the sensitivity variance of the elements 1a and 1b is compensated by the adder to compose the differential response between operating forces to both elements equally, thereby canceling the components corresponding to the disturbing inertial forces almost completely.

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 particularly to a cyclically driven rate gyro such as vibration or rotation.

2. Description of the Related Art There are various devices for measuring the rotation rate with respect to an inertial system, which is generally referred to as inertial angular velocity.
lar rate 5ensor or ^ngular
vel.

-city 5ensor), rate gyro,
Angular rate detector
It is called by various names such as ng 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. 2) The Q-drive moves the measured coordinate system. When the system rotates with respect to the inertial coordinate system, a Coriolis force is applied to the mass element; 3) The force acting on the mass element is detected, and the deviation detection signal is used to detect the Coriolis force in response to the Coriolis force. The components are extracted and subjected to signal processing according to the Coriolis force generation mechanism.
It can be said that an output proportional to the inertial angular velocity is obtained.

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).

One of the problems with such devices is the response to disturbance inertial force. That is, when a disturbance inertial force is applied to the device, this acts on the mass element and causes an error output.

Therefore, when configuring the device, the key point is how to separate the component corresponding to the Coriolis force and the component corresponding to the disturbance inertial force from the deflection detection signal, which is a response to the force acting on the mass element. Become.

Here, since the Coriolis force is proportional to the vector product of the input inertial angular velocity and the drive speed, the Coriolis force acting on the mass element acts in a direction perpendicular to both the instantaneous drive speed and the input inertial angular velocity.

Therefore, when configuring a circulation drive type rate gyro, a pair of mass elements are provided and the mass elements are driven symmetrically in opposite directions, and the difference between the deviation detection signals obtained by mechanical-electrical conversion of the forces acting on each is calculated. , it is common to add a component corresponding to the Coriolis force acting in the opposite direction to cancel out the disturbance inertia force acting in the same direction.

For example, by driving a cantilever-shaped piezoelectric element cyclically,
When the element itself is used as a mass element to which Coriolis force is applied, and at the same time as a deviation detection signal source that detects the force acting on itself and generates a deviation detection signal,
It is common to drive two piezoelectric elements as a pair in opposite directions and connect them in parallel so that the output charges (voltages) for forces acting in opposite directions are added. This pattern is shown in Figure 2 as a block diagram.

In FIG. 2, la and lb are a pair of cantilever-shaped piezoelectric elements that are cyclically driven in opposite directions, and each generates a deflection detection signal 1a'l according to the force acting on itself.
lb' is generated. Deviation detection signal 1a1. lb/ is combined by parallel connection to become 1' and sent to preamplifier 2.

2 is a preamplifier for converting the capacitive, high-impedance output impedance deviation detection signal 1' into a low-impedance voltage signal, and is a charge amplifier that extracts short-circuit charges or a voltage follower (impedance converter) that extracts open voltage. ).

3 is a signal processing circuit that extracts and processes a component corresponding to the Coriolis force from the output signal of the preamplifier 2 to generate an output proportional to the input angular velocity, and is usually constructed using a synchronous detector as a basic element.

According to this configuration, the component corresponding to the Coriolis force included in the deflection detection signal is added, and the component corresponding to the disturbance inertial force is subtracted, so it is true that the response to the disturbance inertial force is relatively attenuated. do.

Problem to be Solved by the Invention However, this damping effect is limited by the consistency of the sensitivity of each deflection sensing signal source in converting the force acting on the two mass elements into an electrical signal.

For example, when a cantilever-shaped piezoelectric element is used as in the above example, several to ten Sensitivity variations on the order of percent are unavoidable.

Furthermore, even if other sources are used as the deviation detection source, the same degree of misalignment is unavoidable.

For example, if this sensitivity mismatch is 10%, the attenuation effect of the disturbance inertial force component in this case is that the component corresponding to the Coriolis force is approximately 2 Although it is about twice as large, the disturbance inertial force component is about one-tenth, so it is relatively only about one-twentieth.

This value becomes a big problem especially in applications where insensitivity to disturbance inertia force is required.

Means for Solving the Problems The present invention solves the above problems by using a symmetrically driven motor.
The above object is achieved by providing an adding means that weights and adds the deflection detection signals obtained by independently detecting the forces acting on the paired mass elements.

Effect: According to the means described above, the component corresponding to the Coriolis force and the component corresponding to the disturbance inertial force included in the deviation detection signal can be limited by the consistency of the sensitivity of the deviation detection signal source. It is possible to perform high-precision separation without any interference, and it is possible to obtain high-performance characteristics with little error response to disturbance inertial force.

Embodiment Hereinafter, an embodiment of the present invention will be described with reference to the drawings, taking as an example a case where a piezoelectric element is used as a deviation detection signal source.

FIG. 1 is a block diagram showing the configuration of a circulation drive type rate gyro in this embodiment.

In Fig. 1, la and lb constitute mass elements on which the Coriolis force is applied, and detect the force acting on itself and generate an electric output (deviation detection signal) la
This is a pair of piezoelectric elements that generate ', lb' and are cyclically driven in opposite directions.

At this time, the deviation detection signals 1a' and 1b' include components corresponding to the Coriolis force as well as components corresponding to the inertia force accompanying the drive, disturbance inertia force, etc., which affect the sensitivity of the respective piezoelectric elements 1a and 1b. Included accordingly.

2a and 2b are piezoelectric elements 1a' which are preamplifiers for converting the deviation detection signals 1a' and 1b' into low impedance voltage signals 2a1 and 2b';

They are wired to output signals of the same polarity when a force in the opposite direction is applied to 1b, and have equal amplification.

Reference numeral 4 denotes an adder that weights and adds 2a' and 2b', and the weighting ratio can be finely adjusted around 1:1.

3 is a signal processing circuit that extracts and processes a component corresponding to the Coriolis force from the output signal of the adder 4 to generate an output proportional to the input angular velocity, and is usually constructed using a synchronous detector as a basic element.

With the above configuration, by compensating for variations in sensitivity between a pair of piezoelectric elements by weighting the adder, differential responses to forces acting on the piezoelectric elements 1a and lb can be equally synthesized, and therefore The component according to the disturbance inertia force can be almost completely canceled out.

In this embodiment, the fine adjustment of the weighting was made immediately after the preamplifier, but this may be done at any stage as long as the signal is being treated as an alternating current; for example, by finely adjusting the gain of the preamplifier. The adder may be fixed.

Furthermore, in this embodiment, a piezoelectric element was used as an example of the deviation detection signal source, but this can be used as long as it can detect the force acting on the driven mass element. For example, a displacement due to a force acting on a mass element may be detected as a capacitance change.

Effects of the Invention As is clear from the detailed explanation above, the circulation drive type rate gyro of the present invention has two units driven symmetrically in opposite directions.
By providing an adding means that weights and adds the deflection detection signals obtained by detecting the forces acting on the paired mass elements,
The components corresponding to the Coriolis force and the disturbance inertia force can be separated with high accuracy without being limited by the consistency of the sensitivity of the deflection detection signal source, resulting in high precision with little response to disturbance inertia force. characteristics can be obtained.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention, and FIG. 2 is a block diagram showing the configuration of a conventional example. la, lb...piezoelectric element, 2.2a, 2b...old...preamplifier, 3...signal processing circuit. Name of agent: Patent attorney Toshio Nakao Haka1 F

Claims (1)

[Claims] a pair of mass elements cyclically driven in opposite directions; a pair of deflection detection signal sources that independently detect forces acting on the pair of mass elements and output electrical signals; A cyclically driven rate gyro comprising: adding means for weighting and adding a pair of deviation detection signal sources.