DE3805250C2 - Angular velocity detector device - Google Patents

Description

The invention relates to a Angular velocity detector device according to the Preamble of claim 1.

An angular velocity detector device of this kind is known from JP 61-193 019 A. With this device will determine the angular velocity a phase comparison. However, this will only receive a relatively weak measurement signal, which is the exact Determining the size of the angular velocity is difficult.

From US-PS 44 09 836 is a device for Determination of the immobility of an object known, the change when rotating a detector the amplitude of an output signal to generate a Detection signal is evaluated.

From US-PS 35 20 195 is one Known angular velocity detector device, at which is the angular velocity of a vibrating body also from the change in the amplitude of a Output signal is determined. With the one in it described device are the on the flanks of the Vibrating body provided piezoelectric Transducer elements divided in two in the longitudinal direction Suppress output signals as much as possible, if no torque acts on the vibrating body. A Circuit for evaluating the determined signals is there not specified.  

A conventional construction of an angular velocity detector device is described in more detail below with reference to FIG. 4 of the drawings. This device comprises a vibrating body ( 1 ) designed as a column with a square cross section and also referred to below as a support, a piezoelectric input transducer ( 2 a) which is attached to a central portion of a longitudinal surface ( 1 a) of the support ( 1 ), and a piezoelectric output transducer ( 2 b) which is attached to a central portion of a further longitudinal surface ( 1 b) of the carrier ( 1 ), the longitudinal surface ( 1 b) extending perpendicular to the longitudinal surface ( 1 a). The carrier ( 1 ) is held at fixed linear positions (a) and (b) by supporting elements ( 3 a, 3 b). The carrier ( 1 ) is driven in a sine wave form by a drive signal being supplied to the piezoelectric input converter ( 2 a). If an angular velocity is added to the carrier ( 1 ) about a central longitudinal axis (Z) of the carrier ( 1 ) while the carrier ( 1 ) is oscillating, a Coriolis force, which changes sinusoidally with an oscillation frequency, becomes perpendicular to the control surface ( 1 a) the carrier ( 1 ) generated. This Coriolis force generates an oscillation which has the same frequency as the control frequency of the carrier ( 1 ). The on the carrier ( 1 ) caused by the Coriolis vibration is detected by the piezoelectric output transducer ( 2 b), which is arranged on the longitudinal surface ( 1 b) perpendicular to the control surface ( 1 a) of the carrier ( 1 ). The detected signal is output to a display circuit (not shown).

A piezoelectric feedback converter ( 2 c), which is used to excite the carrier ( 1 ) with a mechanical resonance frequency, while its amplitude is kept limited to a certain size, is located on a central section of a further longitudinal surface ( 1 c) of the carrier ( 1 ) attached to the rear of the control surface ( 1 a) in parallel, and a piezoelectric damping transducer ( 2 d) is on a central portion of a further longitudinal surface ( 1 d) of the carrier ( 1 ) on the side opposite the longitudinal surface ( 1 b) in parallel attached.

In the known oscillation angular velocity detector device according to FIG. 4, a signal which is amplitude-modulated at an angular velocity and which is detected by the output converter is amplified and the amplified signal is then demodulated. The demodulated signal is then rectified, whereby a direct current signal is obtained which is of a size proportional to the angular velocity on the input side.

As described above, the known Angular velocity detector device Angular velocity by the size of the DC signal detected by demodulating the modulated in relation to the angular velocity Detector signal is obtained and it is a complicated one Signal processing required to change the direction of the capture angular velocity on the input side. As a result, the circuit arrangement becomes complicated.  

The invention has for its object a Angular velocity detector device of the beginning to create the kind that is simple and at the same time exactly how the angular velocity is determined.

According to the invention, this object is achieved with a device solved the features of claim 1.

Further developments of the invention result from the Subclaims.

A preferred embodiment of the invention is described below with reference to FIGS. 1 to 3 of the drawings.

In the drawings shows

Fig. 1 is a block diagram of an inventive angular velocity detecting means,

Fig. 2 shows waveforms for explaining the operation of the apparatus of Fig. 1,

Fig. 3 other waveforms for explaining the operation of the apparatus of Fig. 1 and

Fig. 4 parts of a known angular velocity detector device in a perspective view.

The parts of a known angular velocity detector device shown in FIG. 4 are also used in the embodiment of the angular velocity detector device according to the invention described below and are therefore no longer shown to describe this embodiment.

Referring to FIGS. 1 and 4, the piezoelectric input transducers (2 a) and the piezoelectric feedback transducer (2 c) secured to the carrier (1), that the polarities of their piezoelectric elements can be reversed and as a result, when a drive signal to the piezoelectric input converter ( 2 a) is applied, a feedback signal with a phase shifted by 90 ° compared to the driver signal from the piezoelectric feedback converter ( 2 c).

The feedback signal is fed to an amplifier ( 10 ) for amplification thereof, and then the amplified feedback signal is fed to an automatic gain control ( 11 ), which is subsequently referred to as AGC, in which the level of the amplified feedback signal is kept at a predetermined value. A stabilized feedback signal output from the AGC ( 11 ) is fed to the phase shifter ( 12 ) for shifting the phase of the stabilized feedback signal.

A phase-shifted feedback signal output from the phase shifter ( 12 ) is fed as a control signal to the piezoelectric input converter ( 2 a) and also to a rectifier ( 13 ). The rectified feedback signal is fed from the rectifier ( 13 ) to an input of a comparator ( 14 ). In the comparator ( 14 ), the rectified feedback signal is compared with a reference voltage (V _R ) which is fed to another input of the comparator ( 14 ), and a comparison result is fed from the comparator ( 14 ) to the AGC ( 11 ) in order to amplify it Taxes. Accordingly, the AGC ( 11 ) can output a stabilized feedback signal, the level of which is kept at a certain level corresponding to the reference voltage (V _R ) and thus the control of the carrier ( 1 ), which is controlled by the piezoelectric input transducer ( 2 a), always be performed stably with a certain amplitude. The phase shifted feedback signal is further supplied as a reference phase signal from the phase shifter ( 12 ) to an input of a phase detector ( 15 ).

The output signal output from the piezoelectric display transducer ( 2 b) is fed to an amplifier ( 16 ) for amplifying the output signal. An amplified output signal is fed from the amplifier ( 16 ) to a filter ( 17 ) to remove unnecessary components of the amplified output signal, and a filtered output signal is sent to an amplitude detector ( 18 ) which detects an amplitude of the filtered output signal and an AC signal (∼) accordingly provides the amplitude of the output signal.

The amplified output signal of the amplifier ( 16 ) is further fed to a further input of the phase detector ( 15 ) which compares the phase of the output signal supplied by the amplifier ( 16 ) with the phase of the reference phase signal supplied by the phase shifter ( 12 ) and an AC signal (∼) accordingly of the phase shift between the output signal and the reference phase signal and the direction of the phase shift.

The AC signal outputs from the phase detector ( 15 ) and from the amplitude detector ( 18 ) are each fed to the AC / DC converters ( 19, 20 ), in which the AC signals are converted to DC signals, whereupon the two DC signals are then converted into associated analog / digital converters ( 21, 22 ), which are subsequently referred to as A / D converters, for converting the analog signals into digital signals. The digital signals obtained are fed from the A / D converters ( 21, 22 ) to a signal processor ( 23 ) which comprises, for example, a microcomputer in which the digital signals are processed and the results of this processing are shown on a display ( 24 ) . The converters ( 19, 20 ) and the signal processor ( 23 ) thus form signal processing devices.

The operation of the above-described angular velocity detector device according to the present invention will now be described in detail with reference to FIGS. 2 and 3.

First, a method for detecting the angular velocity based on the phase of the output signal will be described. A waveform (f _F (t)) of the piezoelectric input converter (2 a) to be supplied to the drive signal is given in Fig. 2a by a solid line, and the piezoelectric input converter (2 a) controls the carrier (1) depending on the driving signal and causes it to vibrate according to the waveform of the drive signal. The vibration of the carrier ( 1 ) is stabilized by the AGC ( 11 ). A waveform (f _po (t)), which is indicated in Fig. 2a by a dotted line, is a vibration waveform of the output signal from the piezoelectric output transducer (2 b) is output when no torque is applied to the carrier (1). As can be seen from the comparison between these two waveforms, the phase of the output signal is shifted by 90 ° compared to that of the driver signal.

If a torque is now added to the carrier ( 1 ) in the clockwise direction and this is given an angular velocity (omega₁), the piezoelectric output transducer ( 2 b) delivers an output signal with a waveform (f _{p omega 1} (t)), which is shown in FIG. 2a is indicated by a dashed line. If, on the other hand, a torque is added to the carrier ( 1 ) in the counter-clockwise direction and this is given an angular velocity (omega ₂ ), the phase of the output signal is shifted in the opposite direction to a clockwise rotation and the piezoelectric output transducer ( 2 b) also provides an output signal a waveform (f _{p omega 2} (t)), which is indicated in FIG. 2a by a further broken line.

The driver signal (f _F (t)) and the output signals (f _po (t), f _{p omega 1} (t) and f _{p omega 2} (t)) are fed to the phase detector ( 15 ), in which these waves are square wave as signals (f _F (t) ', f _po (t)', f _{p omega 1} (t) 'and f _{p omega 2} (t)') are transformed, as shown in Fig. 2b. Then the square wave signal (f _F (t) ') with the respective square wave signal (f _po (t)', f _{p omega 1} (t) 'or f _{p omega 2} (t)') is compared and the sections from the same polarity of each of the square wave signals are detected, which means that the phase detector ( 15 ) emits similar square wave signals as shown in FIG. 2c. In Fig. 2c, the wave signal indicated by a solid line is obtained from the two wave signals (f _F (t) 'and f _po (t)') and each of the other wave signals indicated by broken lines is from the two Wave signals (f _F (t) ′ and f _{p omega 1} (t) ′) obtained or from (f _F (t) ′ and f _{p omega 2} (t) ′). It can be seen from Fig. 2c that the continuous time period of the positive and negative levels of each of the square wave signals in which rotational forces are added is longer or shorter than that in the square wave signal in which no torque is added.

The square wave signals shown in Fig. 2c are fed to the AC / DC converter ( 19 ), in which full wave rectification of the square wave signals is performed to obtain signals having the waveforms shown in Fig. 2d, and then the full wave rectified signals are smoothed to obtain the smoothed DC signals shown in Fig. 2e. In Fig. 2e (V ₀₁ ) represents the level of the DC signal when no torque is added. Subsequently, the smoothed DC signals are converted into other DC signals shown in Fig. 2f such that the level (V ₀₁ ) of the DC signal can be set to a zero level, and the converted DC signals shown in Fig. 2f are replaced by the AC / DC converter ( 19 ) issued. In Fig. 2f two DC signals (V₁, V₂) are shown, in which a torque on the carrier ( 1 ) was added clockwise or counterclockwise and the output levels of the DC signals (V₁, V₂) are (V _{omega 1} and V _{omega 2} ). The size and direction of the angular velocities can therefore be determined by the size of the output level (V _{omega 1} , V _{omega 2} ) and their polarities.

Second, a method for detecting the angular velocity based on the amplitude of the display signal is described. In Fig. 3a, three waveforms (f _po (t), f _{p omega 1} (t), f _{p omega 2} (t)) of the output signals represented by a full line and two dotted lines when each no torque to the support ( 1 ) is added when a torque on the carrier ( 1 ) is effective in the clockwise direction and when a torque on the carrier ( 1 ) is effective in the counterclockwise direction. In this case, since it is unnecessary to detect the phase differences of these signals when detecting the amplitude, the three waveforms are shown with the same phase for the sake of simplicity, as can be seen from FIG. 3a. However, the phase signals are actually often different from one another, as can be seen from FIG. 2a. Furthermore, the amplitude changes of the signals are not always determined in accordance with f _{p omega 1} (t) <f _po (t) <f _{p omega 2} (t), as can be seen from FIG. 3a and vice versa. The amplitudes of the waveforms (f _{p omega 1} (t), f _{p omega 2} (t)) can be larger or smaller than those of the waveform (f _po (t)).

The output signals with the waveforms shown in Fig. 3a are supplied from the piezoelectric output transducer ( 2 b) to the amplitude detector ( 18 ) for detecting the amplitudes of the output signals via the amplifier ( 16 ) and the filter ( 17 ), and then the output signals from Amplitude detector ( 18 ) supplied to the AC / DC converter ( 20 ). The full-wave rectification of these signals is carried out in the AC / DC converter ( 20 ), as a result of which the rectified signals shown in FIG. 3b are obtained. The rectified signals are then smoothed in order to achieve the direct current signals shown in FIG. 3c. Then, the smoothed DC signals are converted to other DC signals shown in Fig. 3d so that the level (V ₀₂ ) of the DC signal can be changed to zero level when no torque is added, and the converted DC signals shown in Fig. 3d output by the AC / DC converter ( 20 ).

In Fig. 3d two DC signals (V ₁ ', V ₂ ') are shown, according to which torques are added to the carrier ( 1 ) clockwise and counter-clockwise and the output levels of the DC signals (V ₁ ', V ₂ ') are in each case V _{omega 1} ′, V _{omega 2} ′). Thus, the size of the angular velocity can be detected by means of the size of the output level (V _{omega 1} ', V _{omega 2} '). Further, in the amplitude variations of the output signals obtained when torque is added to the carrier ( 1 ) clockwise and counterclockwise, one is larger and another smaller than that of the output signal obtained when the carrier ( 1 ) is not Torque acts, which is apparent from Fig. 3a, with which the directions of the angular velocity can be detected at the same time by the polarities of the output level (V _{omega 1} ', V _{omega 2} ').

In this embodiment, however, if the amplitude changes of the signals (f _{p omega 1} (t), f _{p omega 2} (t)) are both larger or smaller than that of the signal (f _po (t)), the directions of the angular velocities cannot be recorded.

The DC signal outputs from the AC / DC converters ( 19, 20 ) are supplied to the associated A / D converters ( 21, 22 ) to convert the DC signals into digital signals, and the digital signals are then sent to the signal processor ( 23 ). In the signal processor ( 23 ), the absolute values of the output signals of the A / D converters ( 21, 22 ) are added, and the size of the angular velocities is detected based on the added values. The directions of the angular velocities are also determined by means of the polarities of the output signals of the A / D converter ( 21 ). As described above, the size of the angular velocities

| V _{omega 1} | + | V _{omega 1} ′ | and | V _{omega 2} | + | V _{omega 2} ′ |

can be obtained are the received values around the contributions

| V _{omega 1} ′ | or | V _{omega 2} ′ |

larger than

| V _{omega 1} | and | V _{omega 2} |,

compared with the values from the phase comparison according to FIG. 2, in which the size of the angular velocities can be determined from the phase of the output signal, and therefore a more precise detection of the angular velocity can be achieved with the device according to the invention.

From the foregoing description of the preferred Embodiment it can be seen that because the angular velocities from the phases and the Amplitudes of the display signals are detected by the piezoelectric output transducer attached to the oscillating body read out, strong signals are obtained, which indicate the size of the angular velocity, so that the Accuracy in the detection of angular velocities strong can be improved. Furthermore, the Directions of angular velocities in simple way without complicated signal acquisition be determined.

Claims (8)

1. An angular velocity detector device comprising

• (a) a columnar vibrating body ( 1 ),
• (b) a first on a side face of the vibrating body (1) arranged piezoelectric input converter (2 a) for supplying a driving signal (f _F (t)) for driving the oscillating body (1),
• (c) a piezoelectric output transducer ( 2 b) arranged on a second side surface of the vibrating body ( 1 ) perpendicular to the first side surface for outputting an output signal (f _{p l} ₁ (t), f _{p ω} ₂ (t)) corresponding to an angular velocity ( ω1, ω2) of the vibrating body ( 1 ),
• (d) a phase detector device ( 15 ) for comparing the phase of the output signal (f _{p ω} ₁ (t), f _{p ω} ₂ (t)) with the phase of the drive signal (f _F (t)) and for forming a phase comparison signal and
• (e) a first signal processing device ( 19 ) for forming a first evaluation signal (V₁, V₂) from the phase comparison signal,

marked by

• (f) an amplitude detector device ( 18 ) for forming an amplitude signal from the amplitude of the output signal (f _{p ω} ₁ (t), f _{p l} ₂ (t)),
• (G) a second signal processing device ( 20 ) for forming a second evaluation signal (V₁ ', V₂') from the amplitude signal and
• (h) a third signal processing device ( 23 ) for summing the first and second evaluation signal (V₁, V₂; V₁ ', V₂') and for calculating the size of the angular velocity (ω1, ω2) of the vibrating body ( 1 ) from the sum of the first and second evaluation signal and for calculating the direction of the angular velocity (ω1, ω2) from the first evaluation signal (V₁, V₂).

2. angular velocity detector device according to claim 1, characterized by a gain controller ( 11 ) for stabilizing the applied to the piezoelectric input transducer ( 2 a) driver signal (f _F (t)). 3. angular velocity detector device according to claim 1 or 2, characterized in that the phase detector device ( 15 ) forms the phase comparison signal from signal sections in which the driver signal (f _F (t)) and the output signal (f _{p ω} ₁ (t) , f _{p ω} ₂ (t)) each have the same polarity after conversion into square wave signals. 4. Angular velocity detector device according to claim 3, characterized in that the first signal processing device ( 19 ) forms the first evaluation signal (V₁, V₂) by rectifying and smoothing the phase comparison signal of the phase detector device ( 15 ). 5. Angular velocity detector device according to one of the preceding claims, characterized in that the second signal processing device ( 20 ) forms the second evaluation signal (V₁ ', V₂') by rectifying and smoothing the amplitude signal of the amplitude detector device ( 18 ). 6. Angular velocity detector device according to one of the preceding claims, characterized in that the first signal processing device ( 19 ) and the second signal processing device ( 20 ) set the first and the second evaluation signal such that they each assume the value zero when the angular velocity of the vibrating body Is zero. 7. angular velocity detector device according to one of the preceding claims, characterized in that the third signal processing device ( 23 ) delivers signals corresponding to the determined size and direction of the angular velocity (ω1, ω2) of the vibrating body ( 1 ) to a display device ( 24 ).