CN109032133B - Indoor Mobile Robot Based on Sound Source Localization - Google Patents

Abstract

The invention provides an indoor mobile robot based on sound source positioning, wherein a power supply realizes voltage conversion through a power supply module, the power supply module supplies power to a chassis motor through a motor driving module, a rotating shaft of the chassis motor is connected with a driving wheel, the power supply module also respectively supplies power to an ultrasonic ranging module, an ultrasonic receiving module, a microphone and a singlechip, an ultrasonic signal sent by the ultrasonic ranging module is returned by an obstacle and received by the ultrasonic receiving module, the ultrasonic receiving module sends the signal to the singlechip, and the singlechip realizes obstacle avoidance through the driving wheel by calculation. According to the invention, the three-dimensional coordinate calculation of the sound source position can be realized according to sound localization and under the indoor environment, the trolley is controlled to start from the initial position and automatically draw close to the sound source position, and the function of autonomous obstacle avoidance is realized in the moving process.

Description

Indoor Mobile Robot Based on Sound Source Localization

technical field

The invention belongs to the field of robots, in particular to an indoor mobile robot based on sound source localization.

Background technique

As an intelligent individual facing complex environmental backgrounds, robots are faced with a world of multi-modal information. For various application environments, they have corresponding information processing systems and information acquisition methods, and can make corresponding decisions according to changes in the environment. Equipping robots with various external sensors to enable them to have higher performance indicators and wider application ranges is an important means for robots to develop intelligently.

Robot vision technology has greatly broadened the application range of robots and improved the working efficiency of robots. However, visual perception is limited by line of sight and visibility, and visual perception will fail when the light conditions are poor or obstructed by obstacles.

Contents of the invention

The purpose of the present invention is to solve the above-mentioned defects in the prior art, and to provide an indoor mobile robot based on sound source positioning, which can realize the three-dimensional coordinate calculation of the sound source position in an indoor environment, and control the car to start from the initial position and automatically move to the sound source. The source position is close to realize the function of autonomous obstacle avoidance during the movement.

The present invention adopts following technical scheme:

In the indoor mobile robot based on sound source positioning, the power supply realizes the voltage conversion through the power module, and the power module supplies power to the chassis motor through the motor drive module, and the rotating shaft of the chassis motor is connected to the driving wheel. Ultrasonic receiving module, microphone and single-chip microcomputer. The microphone locates the sound source and sends a signal to the single-chip microcomputer. The single-chip microcomputer sends a signal to the motor drive module, thereby driving the car to move to the position of the sound source. The ultrasonic signal sent by the ultrasonic ranging module is returned by obstacles And received by the ultrasonic receiving module, the ultrasonic receiving module sends the signal to the single-chip microcomputer, and the single-chip microcomputer sends the signal for robot obstacle avoidance through calculation. The array delay estimation algorithm obtains the position of the sound source.

The further technical solution is that the motor drive module includes P3 drive signal interface, P2 motor power interface, P1 motor interface, BTS7960 chip U2, BTS7960 chip U3, 74AHC244 latch U1, P3 drive signal interface and 74AHC244 latch U1, BTS7960 chip U2 and BTS7960 chip U3 are connected, P2 motor power interface is connected with BTS7960 chip U2 and BTS7960 chip U3, P1 motor interface is connected with BTS7960 chip U2 and BTS7960 chip U3, BTS7960 chip U2 is connected with 74AHC244 latch U1, BTS7960 chip U3 is connected with 74AHC244 latch U1 connected.

A further preferred technical solution is that the power supply is equipped with a power supply anti-overvoltage protection circuit, the power supply is a battery, and the battery positive pole of the power supply anti-overvoltage protection circuit is connected to one end of the sliding rheostat resistor R2 and the source of the PMOS transistor Q1, The drain of the PMOS transistor Q1 is connected to the source of the NMOS transistor Q3, the gate of the PMOS transistor Q1 is connected to one end of the resistor R1 and one end of the resistor RL1, the other end of the resistor R1 is connected to the anode of the light-emitting diode D1, and the light-emitting diode D1 The negative pole is connected to the source of MOSFET Q2, the drain of MOSFET Q2 is connected to the other end of sliding rheostat R2 and one end of resistor R3, the gate of MOSFET Q2 is connected to the other end of resistor R3, and the other end of resistor RL1 It is connected to the other end of the resistor R3, the gate of the NMOS transistor Q3 is connected to the resistor R3, the drain of the NMOS transistor Q3 is connected to the other end of the sliding rheostat R2, and the other end of the sliding rheostat R2 is also connected to the resistor R4, The negative electrode of the battery is connected with the other end of the resistor R4 and the other end of the resistor R3.

A further preferred technical solution is that the power supply module includes a 12V voltage stabilizing circuit, a 5V voltage stabilizing circuit, and a 3.3V voltage stabilizing circuit, wherein the 12V voltage stabilizing circuit includes an XL6009 current conversion chip, a 10V power supply input terminal and an input capacitor C1. , one end of the capacitor C2, one end of the inductor L1, and the VIN interface of the XL6009 current conversion chip. One end of capacitor C4 is connected to one end of resistor R2, the other end of resistor R2 is connected to the FB port of XL6009 current conversion chip, FB of XL6009 current conversion chip is connected to one end of resistor R1, the input end of 10V power supply is connected to the other end of input capacitor C1, capacitor The other end of C2, the GND port of the XL6009 current conversion chip, the other end of the resistance wire R1, the other end of the capacitor C3, and the other end of the output capacitor C4 are connected;

The 12V power supply input terminal is connected to one end of capacitor C5 and the VIN of the A1212S-2W isolated power supply module, the other end of capacitor C5 is connected to the GND of the A1212S-2W isolated power supply module and grounded, and the +V and 0V of the A1212S-2W isolated power supply module are connected through The resistor R3 is connected, the -V and 0V of the A1212S-2W isolated power module are connected through the resistor R4, and the A1212S-2W isolated power module is grounded;

The 5V regulated power supply includes the LM2596 chip, the power input terminal is connected to the VIN of the LM2596 chip, and connected to one end of the capacitor C6, the OUT of the LM2596 chip is connected to the inductor L2 and the negative pole of the Zener diode D2, the sliding rheostat RV1, one end of the capacitor C7, and the sliding rheostat RV1 The other end is connected to one end of the resistor R5, the other end of the capacitor C7 is connected to the other end of the resistor R5, the other end of the inductor L2, and one end of the capacitor C8. The FB port of the LM2596 chip is connected to the OUT port and one end of the resistor R6. The OFF port of the LM2596 chip is connected to the GND, the other end of the resistor R6, the other end of the Zener diode D2, the other end of the capacitor C8 are connected, and grounded;

The 3.3V regulated power supply includes AMS1117-3.3V linear voltage regulator, the power input terminal is connected to one end of capacitor C9, one end of capacitor C10, the IN port of AMS1117-3.3V linear voltage regulator, and the OUT port of AMS1117-3.3V linear voltage regulator The terminal is connected to one end of capacitor C11 and one end of capacitor C12, and the terminal of ADJ of AMS1117-3.3V linear voltage regulator is connected to the other end of capacitor C9, the other end of capacitor C10, the other end of capacitor C11, and the other end of capacitor C12, and grounded.

A further preferred technical solution is that the ultrasonic ranging module includes a STC11 single-chip microcomputer, a MAX232 chip amplifier, and a piezoelectric crystal, and the STC11 single-chip microcomputer generates a signal and sends it to the MAX232 chip amplifier, and the MAX232 chip amplifier is connected with the piezoelectric crystal signal to drive the piezoelectric crystal. The crystal generates an ultrasonic signal.

A further preferred technical solution is that the ultrasonic receiving module includes a TLO84 low-noise operational amplifier and a piezoelectric chip, and the piezoelectric chip is connected with the TLO84 low-noise operational amplifier.

A further preferred technical solution is that it also includes a high-pass filter, an amplification filter circuit, and a low-pass filter, and the high-pass filter, the amplification filter circuit, and the low-pass filter are installed in the circuit where the power module is connected to the microphone.

The invention is an indoor mobile robot based on sound positioning, which can realize the three-dimensional coordinate solution of the sound source position in the indoor environment, and control the car to start from the initial position, automatically move closer to the sound source position, and realize the function of autonomous obstacle avoidance during the moving process .

Description of drawings

Fig. 1 is a schematic diagram of a four-wheel differential steering chassis;

Figure 2 is a connection diagram of the motor drive circuit;

Figure 3 is a circuit diagram of the power supply anti-over-discharge protection;

Figure 4 is a 12V power supply voltage regulator circuit XL6009 automatic boost circuit diagram;

Figure 5 is a 12V to 12V power supply for the 12V power supply voltage regulator circuit;

Figure 6 is a step-down circuit diagram of 5VLM2596;

Figure 7 is a 3.3VAMS1117-3.3 step-down circuit diagram;

Fig. 8 is the ultrasonic transmission circuit diagram of ultrasonic ranging module;

Fig. 9 is an ultrasonic receiving circuit diagram;

Fig. 10 is a high-pass filter circuit diagram;

Figure 11 is a schematic diagram of the amplification filter circuit;

Fig. 12 is a schematic diagram of a low-pass filter circuit;

Fig. 13 is a schematic diagram of the structure of an array microphone.

Detailed ways

In order to make the purpose, technical solutions and advantages of the present invention clearer, the following technical solutions in the present invention are clearly and completely described. Apparently, the described embodiments are some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

The indoor mobile robot based on sound source positioning of the present invention includes a chassis mechanism, a power supply, a power supply module, a motor drive module, an ultrasonic obstacle avoidance module, and a single-chip microcomputer. As shown in Figure 1, it is a schematic diagram of a four-wheel differential steering chassis. The chassis mechanism includes the driving wheel and the chassis. The chassis realizes steering through the different speeds of the left and right driving wheels, that is, the speed difference between the driving wheels of the chassis will cause side slip, and the side slip is used for steering.

Four independent driving wheels are installed on the chassis. When the chassis is differentially turned, the speed of the two driving wheels on the right is the same, and the speed of the two driving wheels on the left is the same. The deflection angle of the left driving wheel is α, and the two directions are opposite. =, the chassis will move in a straight line; ->0, the chassis will rotate around the right rotation center; -<0, the chassis will rotate around the left rotation center. The four-wheel differential steering can turn around any radius by using the speed difference between the left and right wheels, and has the advantages of flexible steering, high precision and simple structure.

The power supply, power supply module, motor drive module, ultrasonic obstacle avoidance module and single-chip microcomputer are all arranged on the chassis.

As shown in Figure 2, it is the chassis motor drive circuit diagram. The motor drive module includes P3 drive signal interface, P2 motor power interface, P1 motor interface, BTS7960 chip U2, BTS7960 chip U3, 74AHC244 latch U1, the 1# interface of P3 drive signal interface and the A1 terminal of 74AHC244 latch U1 Connected, the 2# interface of the P3 drive signal interface is connected to the A3 terminal of the 74AHC244 latch U1, the 3# interface of the P3 drive signal interface is connected to the A2 terminal of the 74AHC244 latch U1, and the 4# interface of the P3 drive signal interface is connected to the 74AHC244 latch The A4 terminal of U1 is connected, the 5# interface of the P3 drive signal interface is connected with the IS terminal of the BTS7960 chip U2, the 6# interface of the P3 drive signal interface is connected with the IS terminal of the BTS7960 chip U3, and the Y1 terminal of the 74AHC244 latch U1 is connected with the BTS7960 chip The IN terminal of U2 is connected, the Y2 terminal of the 74AHC244 latch U1 is connected with the INH terminal of the BTS7960 chip U2, the Y3 terminal of the 74AHC244 latch U1 is connected with the IN terminal of the BTS7960 chip U3, and the Y4 terminal of the 74AHC244 latch U1 is connected with the BTS7960 chip U3. The INH terminal is connected; the P2 motor power interface is connected to the OUT terminal of the BTS7960 chip U2 and the OUT terminal of the BTS7960 chip U3; the VS terminal of the BTS7960 chip U2 and the VS terminal of the BTS7960 chip U3 are connected to the P1 motor interface.

The BTS7960 chip consists of a P-type channel high-potential field effect transistor and a N-type channel low-potential field effect transistor to form a fully integrated high-current half-bridge.

Its internal power switch ensures the best resistance state, using advanced vertical field effect transistor technology. Because the switch of the P-type channel is high potential, a charge pump is designed inside to eliminate electromagnetic interference and ensure the stable and reliable operation of the channel.

Internally, the logic level input terminal, current sampling diagnosis, failure time generator, slew rate regulator, protection against undervoltage, slew rate regulator overcurrent, and short circuit structure are connected to a microprocessor through drive integration technology.

Two BTS700 chips are used to form a full-bridge circuit, and a 74AHC244 is added as a data buffer or latch, so that the single-chip microcomputer can change the chip data latch state, release the port data value, and use it to drive other loads.

The rotating shaft of driving wheel is connected with chassis motor rotating shaft.

The chassis motor uses a PWM controller to adjust the motor drive voltage. It is an effective technology that uses the digital output of the microprocessor to control the voltage of the analog circuit. It is applied in the field of motor drive, and the motor drive voltage is adjusted by the width of the pulse signal output by the microprocessor.

In the PWM speed control system, there are generally three ways to change the pulse width, that is, fixed-width frequency modulation, frequency modulation width modulation, and fixed-frequency width modulation. However, fixed-width frequency modulation and frequency modulation width modulation will change the frequency of the control pulse width during speed regulation.

And if the frequency is close to the natural frequency of the system, it will cause resonance, which will cause the motor to vibrate greatly. In order to avoid this situation in actual use, most of them use a method of fixing the natural frequency and adjusting the duty cycle to adjust the voltage at both ends of the DC motor. The formula for its output voltage is T is the period of the pulse signal, and t is the duration of the high level. In order to make the motor work stably and reduce noise, the frequency must be far away from the natural frequency of the motor.

Therefore, the frequency of the motor is generally selected to be at least above 1KHz, and there is generally no obvious motor noise within 10KHz to 20KHz. The selection of the duty cycle is determined by the minimum driving voltage of the motor, and it is generally selected above 20%.

The chassis motor control of the present invention adopts the STM32F103 chip of ARM series for control. Cortex-M3 core with ARM32 bits, 112 fast I/O ports, 11 timers, 13 communication interfaces, 3 12-bit analog-to-digital converters, 2-channel 12-bit D/A converter and 12-channel DMA control device.

As shown in Figure 3, the power supply is equipped with a power supply anti-over-discharge protection circuit.

The power supply is equipped with a power supply anti-overvoltage protection circuit, the power supply is a battery, the positive electrode of the battery in the power supply anti-overvoltage protection circuit is connected to one end of the sliding rheostat resistor R2, and the source of the PMOS transistor Q1, and the drain of the PMOS transistor Q1 is connected to the NMOS. The source of the tube Q3 is connected, the gate of the PMOS tube Q1 is connected to one end of the resistor R1 and one end of the resistor RL1, the other end of the resistor R1 is connected to the anode of the light-emitting diode D1, and the cathode of the light-emitting diode D1 is connected to the source of the MOSFET tube Q2 The drain of the MOSFET Q2 is connected to the other end of the sliding rheostat R2 and one end of the resistor R3, the gate of the MOSFET Q2 is connected to the other end of the resistor R3, and the other end of the resistor RL1 is connected to the other end of the resistor R3 , the gate of the NMOS transistor Q3 is connected to the resistor R3, the drain of the NMOS transistor Q3 is connected to the other end of the sliding rheostat R2, the other end of the sliding rheostat R2 is also connected to the resistor R4, and the negative electrode of the battery is connected to the other end of the resistor R4 , The other end of the resistor R3 is connected.

When the battery voltage is discharged too low, the battery cannot be activated because the internal primary battery reaction is too weak.

The power supply anti-overvoltage protection circuit of this device uses high-power NMOS and PMOS tubes to form a power switch circuit. When the power supply voltage is lower than the set value, the NMOS is cut off when the resistance is sealed and the PMOS is cut off. When the battery voltage is at the threshold of the over-discharge protection voltage , the LED light will go out, and the current should be removed in time for charging.

A further preferred technical solution is that the power module includes a 12V voltage stabilizing circuit, a 5V voltage stabilizing circuit, and a 3.3V voltage stabilizing circuit.

The 12V regulator circuit is, as shown in Figure 4, the 12V power supply module includes a 12V regulator circuit, a 5V regulator circuit, and a 3.3V regulator circuit, wherein the 12V regulator circuit includes an XL6009 current conversion chip, and a 10V power supply The input end is connected to one end of the input capacitor C1, one end of the capacitor C2, one end of the inductor L1, and the VIN interface of the XL6009 current conversion chip. The other end of the inductor L1 is connected to the positive pole of the Zener diode D1 and the SW port of the XL6009 current conversion chip. The negative electrode is connected to one end of capacitor C3, one end of output capacitor C4, and one end of resistor R2. The other end of resistor R2 is connected to the FB port of the XL6009 current conversion chip. The FB of the XL6009 current conversion chip is connected to one end of the resistor R1. The other end of the input capacitor C1, the other end of the capacitor C2, the GND port of the XL6009 current conversion chip, the other end of the resistance wire R1, the other end of the capacitor C3, and the other end of the output capacitor C4 are connected.

Because the battery voltage output is unstable and fluctuates around 11V, and because the start and stop of the chassis motor will form a pulse voltage, the circuit needs an automatic boost circuit.

The XL6009 current conversion chip has a wide input voltage range of 5-32V, a switching frequency of 400KHz, a maximum switching current of 4A, a conversion efficiency of 94%, and software startup.

As shown in Figure 5, after the 12V voltage is obtained, the power input terminal is connected to one end of the capacitor C5 and the VIN of the A1212S-2W isolated power module, and the other end of the capacitor C5 is connected to the GND of the A1212S-2W isolated power module and grounded, and the A1212S-2W isolated power module The +V and 0V of the power module are connected through the resistor R3, the -V and 0V of the A1212S-2W isolated power module are connected through the resistor R4, and the A1212S-2W isolated power module is grounded.

The positive and negative 12V power supply can be obtained by means of switching power supply isolation from the 12V power supply. Using isolated power module A1212S-2W, the conversion efficiency is above 80%, the output voltage range is ±12V±3%, the ripple coefficient and quiescent current are low, and it has its own input and output filters.

As shown in Figure 6, the 5V regulated power supply includes the LM2596 chip. The input terminal of the power supply is connected to the VIN of the LM2596 chip and connected to one end of the capacitor C6. One end of C7, the other end of sliding rheostat RV1 is connected to one end of resistor R5, the other end of capacitor C7 is connected to the other end of resistor R5, the other end of inductor L2, and one end of capacitor C8. The FB port of LM2596 chip is connected to OUT port and one end of resistor R6. One end of C6 is connected to the OFF port of the LM2596 chip and the GND of the LM2596 chip, the other end of the resistor R6, the other end of the Zener diode D2, the other end of the capacitor C8, and grounded.

The 5V regulated power supply is obtained from the 12V power supply. The LM2596 chip is used. The performance is superior. The error of the output voltage can be guaranteed within the range of ±4%, and the error of the oscillation frequency is within the range of ±15%. The step-down circuit uses LM2596 as the core.

As shown in Figure 7, the 3.3V regulated power supply includes an AMS1117-3.3V linear regulator. The OUT terminal of the voltage regulator is connected to one end of the capacitor C11 and one end of the capacitor C12, and the ADJ terminal of the AMS1117-3.3V linear regulator is connected to the other end of the capacitor C9, the other end of the capacitor C10, the other end of the capacitor C11, and the other end of the capacitor C12 and ground.

The 3.3V regulated power supply is obtained from the 5V power supply. The chip selects the linear voltage regulator AMS1117-3.3V. This chip is the best among the regulated chips and has better performance. The accuracy of the voltage regulation is within 1.5%, and almost no external devices are needed, but in general use, capacitors are used to improve the output voltage pulse curve.

In order to ensure the maximum output current, the voltage difference between the input and output should be at least 1.3V, which should not be too high, which is quite reasonable for an input voltage of 5V. AMS117 has a wide market share, and the package generally adopts SOT-223.

The 3.3V power supply supplies power to the STM32 microcontroller, which has low power consumption and meets the requirements. The single-chip microcomputer requires the power supply ripple to be small, so the combination of large capacitors and small capacitors can be used to improve the power supply ripple.

As shown in Figure 8, it is an ultrasonic ranging module. The ultrasonic ranging module includes an STC11 single-chip microcomputer, a MAX232 chip amplifier, and a piezoelectric crystal. The STC11 single-chip microcomputer generates a signal and sends it to the MAX232 chip amplifier, and the MAX232 chip amplifier drives the piezoelectric crystal to generate Ultrasonic signal.

The ultrasonic transmitting circuit adopts STC11 single-chip microcomputer to generate signal, and the MAX232 chip amplifies it to drive the piezoelectric crystal. When it is detected that the TX pin level is high, STC11 microcontroller P1.6 and P1.7 generate eight 40KHz pulse waves with a phase difference of 180°, which are amplified by MAX232 to make the piezoelectric crystal oscillate to generate ultrasonic signals.

When using the ultrasonic ranging module for distance measurement, the TX input needs a high level of at least 20us. After the transmission is completed, turn on the microcontroller timer for timing. When it is detected that the RX transitions from a high level to a low level, the timer is turned off, the timer value is taken out, and the timing time is calculated. Then the distance can be obtained by multiplying the timing time by the speed of sound 340m/s, and this distance is the actual distance of ultrasonic ranging.

As shown in FIG. 9 , it is an ultrasonic receiving module. The ultrasonic receiving module includes a TLO84 low-noise operational amplifier and a piezoelectric wafer, and the piezoelectric wafer is connected with the TLO84 low-noise operational amplifier.

The single-chip microcomputer opens P1.0 and P1.1 port detection, and sets this port as high level. When it is detected that the P1.1 port signal is pulled low, the RX high level signal is output. Here, it is required that the RX signal terminal remains in a low level state when it is usually idle. The ultrasonic receiving circuit is composed of TLO84 low-noise op amp. After preamplification, second-order active filtering, amplification, voltage comparison, and triode switching circuit output ultrasonic signals. After the module does not receive feedback data for 38ms, it defaults to timeout.

Based on the time delay estimation algorithm _of the spatial five-element _microphone array, _a spatial five- _element microphone array as shown in Figure _{13 is} established. , N ₂ , N ₃ , and N ₄ have a side length of 2L, the distance from the microphone N ₅ to the origin of the coordinates is L, and the center of the square matrix is the origin of the coordinates O, and establish a space Cartesian coordinate system as shown in Figure 13. Assuming that the location of the target is located at S(x,y,z), the distance between the target and the origin of the coordinates is r, and the azimuth of the target is is the elevation angle θ.

The coordinates of each element of the spatial five-element microphone array are: N ₁ (L,L,0), N ₂ (-L,L,0), N ₃ (-L,-L,0), N ₄ (L ,-L,0), N ₅ (0,0,L), R _i is the distance from the target S to the array element N _i (i=1,2,3,4,5), d ₁₂ , d ₁₃ , d ₁₄ is the sound path difference between the reference array element N ₁ and N ₂ , N ₃ , N ₄ , and C represents the propagation speed of sound in the air. The formula for calculating the sound path difference is as follows:

d _1i =R _i -R ₁ =C*t _i1 (i=2,3,4) (1)

In the formula, t _i1 is the time delay between the reference array element N ₁ and N ₂ , N ₃ , N ₄ .

According to the geometric position relationship between the target and the sound array:

Arranging and simplifying the equation group (2) can get:

Substituting equation (3) into equation group (2) and sorting out:

Through the above equations (4) and equations (1), as long as the time delay is estimated, x, y, z and R ₁ can be obtained, and the azimuth angle can be obtained at the same time:

The elevation angle is:

According to the geometric position of the sound array and the equation group (4), it can be obtained;

If R ₅ >r, it proves that the sound source coordinates are above the XOY plane; if R ₅ <r, it proves that the sound source coordinates are below the XOY plane.

This method can solve the problem that the obtained sound source coordinates may have two mirror coordinates, due to the defects of the planar quaternary matrix itself, but the calculation amount does not increase much compared with the planar quaternary matrix, which is very practical sex.

As shown in Figure 10, it is a short circuit diagram of a high-pass filter. When using a microphone, it is necessary to filter the DC component in the microphone signal, and the low frequency component in the signal should also be filtered out, otherwise 50Hz power frequency interference will be introduced into the latter part of the circuit.

As shown in Figure 11, it is an amplification filter circuit. The frequency of human speech is 300Hz-3400Hz, and the frequency band is relatively narrow, so it is realized by multi-stage band-pass filter. And because the electrical signal current obtained by the microphone is small, it needs to be amplified and filtered. The form of passive filtering has a wider bandwidth at the same frequency. Therefore, the signal is amplified and filtered in the form of an active filter. The amplified signal is composed of OP07 op amp, and of course integrated filters provided by some manufacturers can also be used.

The OP07 is a low noise, non-chopper-zero-stable, bipolar operational amplifier. The input offset voltage of OP07 is very low, no additional zero adjustment measures are required, the input bias current of OP07 is low, and the open-loop gain is high, so OP07 is suitable for high-gain measurement equipment and weak signals of amplified sensors. The positive and negative 12V power supply is filtered with a 0.1uF capacitor to avoid low-frequency interference caused by power supply noise. Resistor R8 is used to adjust the gain.

The circuit adopts differential amplification to form instrument amplification, which can effectively suppress common-mode noise and improve differential-mode amplification capability. The amplification factor is 1+2R7/R8, and the minimum gain is more than 100 times.

As shown in Figure 12, it is a circuit diagram of a low-pass filter. The frequency of human voice is generally within 30 to 3400HZ. Combined with the high-pass filter designed at the front end, a low-pass filter needs to be designed here. It is generally believed that a signal passing through a filter will generate a phase offset related to its frequency. If the relationship between the phase offset and the signal frequency is linear, then the filter will only delay the signal by a constant amount. However, if the offset is nonlinear relative to the change with the signal frequency, that is, signals with different frequencies will have different displacements after passing through the filter, then the non-sinusoidal signal will produce serious distortion when passing through this filter. Therefore, a Chebyshev low-pass filter is used in the design, the passband gain is less than -5dB, the stopband gain is 10KHz, the attenuation is greater than -50dB, and the rated load of the filter is 50Ω. The filter does not use the amplification function, the amplification factor is 1, the internal circuit uses a resistance of 51Ω, the precision is 5%, the filter capacitor adopts a monolithic capacitor, and the mobility is 1%.

Working process of the present invention:

Turn on the power supply, the microphone array receives the sound source signal, and judges the position of the sound source to calculate the coordinates, and drives the chassis motor to move through the single-chip microcomputer. During the movement, the ultrasonic ranging module and the ultrasonic receiving module receive signals to judge whether obstacles are on the traveling route, and the single-chip microcomputer controls the chassis. The motor turns accordingly, and the robot arrives at the sound source after avoiding obstacles several times.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: it can still be Modifications are made to the technical solutions described in the foregoing embodiments, or equivalent replacements are made to some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims (4)

1. The indoor mobile robot based on sound source localization is characterized in that a power supply realizes voltage conversion through a power supply module, the power supply module supplies converted electric energy to a chassis motor through a motor driving module, a rotating shaft of the chassis motor is connected with a driving wheel, the power supply module also respectively supplies electric energy with different voltage requirements to an ultrasonic ranging module, an ultrasonic receiving module, a microphone and a singlechip, the microphone localizes a sound source and sends signals to the singlechip, the singlechip sends signals to the motor driving module so as to drive a trolley to move to the sound source position, ultrasonic signals sent by the ultrasonic ranging module are returned by an obstacle and received by an ultrasonic receiving module, the ultrasonic receiving module sends the signals to the singlechip, the singlechip sends signals to the robot for obstacle avoidance through calculation, the number of microphones is 5, a quadrangular pyramid microphone array is formed, and the position of the sound source is obtained by adopting a space five-membered microphone array time delay estimation algorithm;

the motor driving module comprises a P3 driving signal interface, a P2 motor power interface and a P1 motor interface, wherein the P3 driving signal interface is connected with the 74AHC244 latch U1, the BTS7960 chip U2 and the BTS7960 chip U3, the P2 motor power interface is connected with the BTS7960 chip U2 and the BTS7960 chip U3, the P1 motor interface is connected with the BTS7960 chip U2 and the BTS7960 chip U3, the BTS7960 chip U2 is connected with the 74AHC244 latch U1, and the BTS7960 chip U3 is connected with the 74AHC244 latch U1;

the power supply is provided with a power supply overvoltage protection circuit, the power supply is a battery, the positive electrode of the battery of the power supply overvoltage protection circuit is connected with one end of a sliding rheostat resistor R2 and the source electrode of a PMOS tube Q1, the drain electrode of the PMOS tube Q1 is connected with the source electrode of an NMOS tube Q3, the grid electrode of the PMOS tube Q1 is connected with one end of the resistor R1 and one end of a resistor RL1, the other end of the resistor R1 is connected with the positive electrode of a light-emitting diode D1, the negative electrode of the light-emitting diode D1 is connected with the source electrode of a MOSFET tube Q2, the drain electrode of the MOSFET tube Q2 is connected with the other end of the sliding rheostat R2 and one end of the resistor R3, the grid electrode of the MOSFET tube Q2 is connected with the other end of the resistor R3, the drain electrode of the NMOS tube Q3 is connected with the other end of the sliding rheostat R2, the other end of the sliding rheostat R2 is also connected with the resistor R4, and the negative electrode of the battery is connected with the other end of the resistor R3;

the power module comprises a 12V voltage stabilizing circuit, a 5V voltage stabilizing circuit and a 3.3V voltage stabilizing circuit, wherein the 12V voltage stabilizing circuit comprises an XL6009 current conversion chip, a 10V power input end is connected with one end of an input capacitor C1, one end of a capacitor C2, one end of an inductor L1 and a VIN interface of the XL6009 current conversion chip, the other end of the inductor L1 is connected with the anode of a voltage stabilizing diode D1 and the SW port of the XL6009 current conversion chip, the cathode of the voltage stabilizing diode D1 is connected with one end of a capacitor C3, one end of an output capacitor C4 and one end of a resistor R2, the other end of the resistor R2 is connected with the FB port of the XL6009 current conversion chip, the 10V power input end is connected with the other end of the input capacitor C1, the other end of the capacitor C2, the GND port of the XL6009 current conversion chip, the other end of a resistance wire R1, the other end of the capacitor C3 and the other end of the output capacitor C4;

the 12V power input end is connected with one end of a capacitor C5 and VIN of an A1212S-2W isolation power supply module, the other end of the capacitor C5 is connected with GND of the A1212S-2W isolation power supply module and grounded, +V and 0V of the A1212S-2W isolation power supply module are connected through a resistor R3, and-V and 0V of the A1212S-2W isolation power supply module are connected through a resistor R4, and a 0V port of the A1212S-2W isolation power supply module is grounded;

the 5V stabilized voltage power supply comprises an LM2596 chip, wherein the power supply input end is connected with VIN of the LM2596 chip and is connected with one end of a capacitor C6, OUT of the LM2596 chip is connected with an inductor L2 and the negative electrode of a voltage stabilizing diode D2, a sliding rheostat RV1 and one end of a capacitor C7, the other end of the sliding rheostat RV1 is connected with one end of a resistor R5, the other end of the capacitor C7 is connected with the other end of the resistor R5, the other end of the inductor L2 and one end of a capacitor C8, the FB port of the LM2596 chip is connected with the OUT port and one end of the resistor R6, the other end of the capacitor C6 is connected with the OFF port of the LM2596 chip, the GND port of the LM2596 chip, the other end of the resistor R6 and the other end of the voltage stabilizing diode D2, and the other end of the capacitor C8;

the 3.3V stabilized voltage power supply comprises an AMS1117-3.3V linear voltage stabilizer, wherein the power supply input end is connected with one end of a capacitor C9, one end of a capacitor C10 and an IN port of the AMS1117-3.3V linear voltage stabilizer are connected, an OUT end of the AMS1117-3.3V linear voltage stabilizer is connected with one end of a capacitor C11 and one end of a capacitor C12, and an ADJ end of the AMS1117-3.3V linear voltage stabilizer is connected with the other end of the capacitor C9, the other end of the capacitor C10, the other end of the capacitor C11 and the other end of the capacitor C12 and grounded.

2. The indoor mobile robot based on sound source localization of claim 1, wherein the ultrasonic ranging module comprises an STC11 single-chip microcomputer and a MAX232 chip amplifier, the piezoelectric crystal generates a signal and sends the signal to the MAX232 chip amplifier, and the MAX232 chip amplifier is connected with the piezoelectric crystal signal to drive the piezoelectric crystal to generate an ultrasonic signal.

3. The indoor mobile robot based on sound source localization of claim 1, wherein the ultrasonic receiving module comprises a TLO84 low noise op-amp, a piezoelectric wafer, and the piezoelectric wafer is connected with the TLO84 low noise op-amp.

4. The sound source localization-based indoor mobile robot of claim 1, further comprising a high-pass filter, an amplifying filter circuit, and a low-pass filter, wherein the high-pass filter, the amplifying filter circuit, and the low-pass filter are installed in a circuit in which the power module is connected to the microphone, and the low-pass filter is a chebyshev low-pass filter.