WO2003011482A1

WO2003011482A1 - Signal horn with adaptively modifiable operating variables

Info

Publication number: WO2003011482A1
Application number: PCT/DE2002/002483
Authority: WO
Inventors: Antonio Pérez BALLALTAS; Jacinto Martin Acero; Fernando Nozal Martin; Matias J. Garrido Gonzalez; Juan M. Meneses Chaus; César RODRIGUEZ LACRUZ; César SANZ ALVARO
Original assignee: Robert Bosch Gmbh
Priority date: 2001-07-25
Filing date: 2002-07-06
Publication date: 2003-02-13
Also published as: DE50205530D1; EP1414590A1; ES2254716T3; DE10136182C1; EP1414590B1; ATE314893T1; CN1301803C; CN1535187A; JP4076161B2; JP2004536355A

Abstract

The invention relates to a signal horn upon which external influences have an effect which is as minor as possible. The inventive signal horn comprises a control circuit for adaptively modifying an operating variable in order to bring it into line with a predefinable set-point value. A switch (6);controlled by a pulse generator (6); is used to control an excitation current (I) flowing through the signal horn in relation to the pulse frequency and/or pulse-scan ratio. Switching means (11) which detect one or several characteristic variables of the excitation current (I) are provided, in addition to other switching means (12) which provide one or several manipulated variables for the pulse generator (6) from the deviation between the characteristic variable(s) derived from the excitation current (I) and one or several set-point values.

Description

Signal horn with adaptively adjustable operating size

State of the art

The present invention relates to a horn with a control loop for adaptively tuning an operating variable of the signaling horn to a predefinable setpoint value, with a controlled from a pulse generator circuit with respect to its pulse frequency and / or its pulse-duty factor controls a current flowing through the horn excitation current ^"and wherein the control circuit Has circuit means which detect an operating variable of the signal horn and depending on it control the pulse generator so that the operating variable of the signal horn assumes the target value.

Such a signal horn with a control loop for adaptive tuning of its resonance frequency is known from US 5,414,406. The actual switching frequency of the signal horn is measured by means of an acoustic sound sensor (microphone) and the phase offset between this measured actual signal and the pulse sequence controlling the signal horn and generated by a pulse generator is determined. The pulse frequency of the pulse generator is adjusted so that the phase shift is minimal. With this activation of the signal horn, it reaches its optimal working frequency, namely its Resonanzrfrequenz. The detection of the actual operating variable of the signal horn by means of an acoustic sound sensor is technically relatively complex. In addition, the function of an acoustic sound sensor is very much dependent on temperature and aging influences; that is, the sound frequency of the signal horn measured by the sound sensor is falsified due to temperature and aging influences. The control loop will then no longer be able to correctly tune the signal horn to its resonance frequency.

The invention is therefore based on the object of specifying a signal horn of the type mentioned at the outset which can be implemented as simply as possible in terms of production technology and in which external influences have as little effect on the operating behavior.

Advantages of the invention

The stated object is achieved with the features of claim 1 in that circuit means are present which detect one or more characteristic quantities of the excitation current flowing through the signal horn and in that further circuit means are present which result from the difference between the excitation current (s) derived characteristic variable (s) and one or more setpoints provide one or more manipulated variables for a pulse generator which controls a switch which controls the excitation current with respect to its pulse frequency and / or its pulse duty cycle. Because the actual operating variable of the signal horn is derived from the excitation current in the control loop, a noise sensor susceptible to failure, which measures the sound frequency of the signal horn, can be dispensed with. Advantageous developments of the invention emerge from the subclaims.

It is expedient to use the resonance frequency or a variable proportional to it - preferably the excitation current - for the control process as the operating variable of the horn.

The characteristic variable (s) of the excitation current is (are) preferably the relative phase position of harmonic spectral components of the excitation current and / or the spectral distribution of the excitation current. These characteristic quantities of the excitation current can be detected by a frequency analyzer.

An advantageous arrangement is that there is a current-voltage converter that converts the excitation current into a voltage, that there is an analog-to-digital converter that digitizes the voltage, and that there is a digital frequency analyzer that a or several characteristic quantities of the digitized voltage curve derived from the excitation current are determined. A signal processor is expediently used which compares the characteristic quantity (s) of the excitation current or the voltage derived therefrom ascertained by the frequency analyzer with one or more nominal values and from the deviations between the characteristic quantity (s) ) and the setpoint (s) provides one or more manipulated variables for the pulse generator. The signal processor can carry out the setpoint comparison at periodically repeating time intervals.

One or more setpoints, which correspond to a fixed operating variable of the signal horn, can be be stored, or one or more changeable setpoints can be supplied to the signal processor. With this last-mentioned version, the signal horn can be varied in its sound.

drawing

The invention is explained in more detail below with the aid of two exemplary embodiments shown in the drawing. Show it:

1 shows a block diagram of a control circuit for adaptively tuning an operating variable of a signal horn, the control circuit being set to a fixed resonance frequency of the signal horn, and

FIG. 2 shows a control circuit for adaptively adjusting an operating variable of a signal horn, the sound of the signal horn being variable.

Description of exemplary embodiments

FIG. 1 shows a block diagram of a control circuit for adaptively tuning an operating variable of a signal horn. The signal horn 1 has a structure as described, for example, in US Pat. No. 5,414,406, of which only one excitation coil 2 is shown in FIG. 1, which causes a membrane of the signal horn to vibrate when current flows through it. The excitation coil 2 of the signal horn 1 is fed by an energy source 3, for example a vehicle battery. In the supply line between the energy source 3 and the excitation coil 2 there is a switch 4, the actuation of which activates the signal horn. The current I flowing through the excitation coil 2 is controlled by an electrically controllable switch 5 inserted into the circuit of the excitation coil 2. The control signal for the electrically controllable switch 5 comes from a pulse generator 6 which emits a pulse train with a specific pulse repetition frequency and with a specific pulse duty cycle. A driver 7 connected between the pulse generator 6 and the electrically controllable switch 5 brings the pulse sequence emitted by the pulse generator 6 to a suitable one for the electrically controllable switch 5

Level. The electrically controllable switch 5 is preferably a semiconductor switch, e.g. a field effect transistor. The electrically controllable switch 5 is therefore switched on and off in accordance with the pulse sequence generated by the pulse generator 6, and as a result the excitation current I flowing through the excitation coil 2 takes the form of a pulse sequence with the pulse frequency and pulse duty cycle predetermined by the pulse generator 6.

It is the task of the control loop described below to operate the signal horn constantly at its resonance frequency regardless of signs of aging or temperature influences or other external influences, which is caused by the entire structure of the signal horn, the excitation coil, a magnetic core, a membrane, the housing and other parts of the horn, depends. An operating variable of the horn 1 is recorded as the controlled variable. The operating variable of the signal horn 1 is advantageously its resonant frequency or a variable proportional to it, namely the excitation current I flowing through the excitation coil 2 and the electrically controllable switch 5.

In the exemplary embodiment shown in FIG. 1, the excitation current I itself is not supplied to the control loop as a control variable, but rather one from the excitation current I. derived voltage. U. the conversion of the excitation current I into the voltage U takes place by means of a current-voltage converter, which in the simplest case is an ohmic resistor 8.

In a circuit part 9 following the current-voltage converter 8, the voltage U is brought to a signal level suitable for a subsequent analog-digital converter 10. The analog-to-digital converter 10 is required if the further signal processing in the control loop is to take place digitally. In the case of analog signal processing, the analog-to-digital converter 10 can be dispensed with. The digitized controlled variable, namely the voltage U, is fed to a digital frequency analyzer 11. The frequency analyzer 11 determines one or more characteristic quantities of the voltage signal U. Characteristic quantities can be, for example, relative phase positions of certain harmonic spectral components and / or the spectral distribution of the signal U.

^'The frequency analyzer 11 from the determined one or more characteristic quantities of the signal U a signal processor 12 are supplied. In the signal processor 12 are stored desired values of these characteristic sizes, namely corresponding to a desired operation of a desired size ^'excitation current profile I of the horn. 1 The signal processor 12 determines deviations between the variable (s) determined by the frequency analyzer 11 and the target value (s) stored in the signal processor 12. The signal processor 12 provides one or more manipulated variables proportional to these deviations for the pulse generator 6. The one or more manipulated variables serve to control the pulse frequency and / or the pulse duty cycle of the pulse generator 6. The pulse rate and / or the pulse rate are Duty cycle of the pulse generator 6 is coordinated in such a way that "the deviations between the actual values and setpoints determined in the signal processor 12 become minimal, and thus the signal horn 1 is operated at its optimal frequency, namely the resonance frequency.

The signal processor 12 receives a start signal S when the switch 4 is actuated to activate the signal horn. The signal processor 12 preferably carries out the comparison between one or more stored nominal values and one or more actual values supplied by the frequency analyzer 11; i.e. the control process is not started permanently but at certain repeating intervals. Every time a control process is initiated by the signal processor 12, the latter reports to the

Analog-digital converter 10 from a start signal A, whereupon the analog-digital converter converts the analog input signal U into a digital signal for the frequency analyzer 11. The analog-to-digital converter 10 need not necessarily only in the times of the signal processor 12 initiated

Control process can be activated, but can carry out the analog-digital conversion continuously.

In the exemplary embodiment shown in FIG. 2, the control circuit has the same circuit parts as in the previously described exemplary embodiments in FIG. 1. Therefore, all switching blocks in FIG. 2 also have the same reference numerals as in FIG

The exemplary embodiment in FIG. 2 differs from that in FIG. 1 only in that the signal processor 12 has a separate signal input 13. In the description of the exemplary embodiment shown in FIG. 1, it was mentioned that one or more predefined setpoints are stored in the signal processor 12. The one indicated in FIG. 2 Signal input 13 for the signal processor 12 now makes it possible to supply setpoints from outside which allow the frequency of the signal horn 1 to be changed in deviation from its resonance frequency. Thus, the tone generated by the bugle 1 can be frequency and also in frequency

Volume can be varied. The changeable setpoints given to the signal input 13 of the signal processor 12 can come, for example, from a central control unit in the motor vehicle. In this case, the switch 4 shown in the exemplary embodiment in FIG. 1 is also omitted.

This is because the signal processor 12 also receives a start signal for the activation of the signal horn 1 via the signal input 13. The signal horn 1 is switched on in this case starting from the signal processor 12 via the pulse generator 6 and the electrically controllable switch 5, which closes the circuit of the excitation coil 2 ,

The circuit blocks 5, 6, 7 and 8, 9, 10, 11, 12 described above do not have to be separate circuits, but they can also be integrated with one another in a suitable manner.

Claims

Expectations

1. Signal horn with a control circuit for adaptively adjusting an operating variable of the signal horn (1) to a predeterminable target value, a switch (5) controlled by a pulse generator (6) having an excitation current (I) flowing through the signal horn (1) with respect to it

Controls pulse frequency and / or its pulse duty cycle and the control circuit has circuit means (8, 9, 10, 11, 12) which detect an operating variable of the signal horn (1) and, depending on this, control the pulse generator (6) so that the Company size of the

Signal horn (1) assumes the target value, characterized in that there are circuit means (11) which detect one or more characteristic quantities of the excitation current (I), and that there are further circuit means (12) which consist of the

Deviation between the characteristic variable (s) derived from the excitation current (I) and one or more setpoints provide one or more manipulated variables for the pulse generator (6).

2. Signal horn according to claim 1, characterized in that the operating variable of the signal horn (1) is its resonance frequency or a variable proportional to it - preferably the excitation current (I).

3. Signal horn according to claim 1, characterized in that the characteristic (n) size (s) of the excitation current (I), the relative phase position of harmonic spectral components of the excitation current (I) or a voltage derived therefrom (U) and / or the spectral distribution of the

Erre ^'gerst roms (I) or a voltage (U) derived from it is (are).

4. Signal horn according to one of claims 1 or 3, characterized in that a frequency analyzer (11) detects the characteristic (n) size (s) of the excitation current (I) or a voltage (U) derived therefrom.

5. Signal horn according to claim 1, characterized in that a current-voltage converter (8) is present, which

Excitation current (I) is converted into a voltage (U), that there is an analog-to-digital converter (10) that digitizes the voltage (U), and that a digital frequency analyzer (11) is available that has one or more characteristic quantities - preferably the relative phase position of harmonic spectral components and / or the spectral distribution - of the digital voltage curve (U) derived from the excitation current (I) is determined.

6. Signal horn according to one of claims 1, 4 or 5, characterized in that a signal processor (12) is present, which is determined by the frequency analyzer (11) (n) characteristic (n) size (s) of the excitation current (I) or compares the voltage (ü) derived therefrom with one or more target values and provides one or more manipulated variables for the pulse generator (6) from the deviations between the characteristic variable (s) and the target value (s).

7. Signal horn according to one of claims 1 or 6, characterized in that the signal processor (12) carries out the setpoint comparison at periodically repeating time intervals.

8. Signal horn according to one of claims 1 or 6, characterized in that one or more setpoints which correspond to a fixed operating variable of the signal horn (1) are stored in the signal processor (12).

9. Signal horn according to one of claims 1 or 6, characterized in that the signal processor (12) one or more variable setpoints can be supplied.