CN110575371A - An intelligent blind guide stick and its control method - Google Patents

Abstract

An intelligent blind-guiding stick and a control method belong to the technical field of intelligent walking sticks. Technical solution: the handle is connected to the connection box through the cane bracket, the connection box is connected to the bottom wheel, the control system is set in one or more of the handle, the cane bracket, and the connection box, and the main controller is connected to the GPS positioning system, infrared Tracking system, fall detection system, ultrasonic barrier system, voice broadcast system, power supply system, wireless transmission system connection. Beneficial effects are: the intelligent blind guide stick described in the present invention is a multi-functional driven intelligent blind guide stick that integrates functions such as GPS positioning, wireless call for help, infrared tracking, ultrasonic obstacle avoidance, etc.; , the whole process of navigation and positioning, infrared tracing of the blind road during the journey, medium and long-distance ultrasonic obstacle avoidance, intimate voice and music broadcast function during the arrival process, anti-lost and anti-fall reminders, intelligent distress device, self-charging system, etc.

Description

An intelligent blind guide stick and its control method

technical field

The invention belongs to the technical field of smart walking sticks, in particular to an smart walking stick for guiding the blind and a control method.

Background technique

The current development status at home and abroad:

1.1 The development status of science and technology at home and abroad

(1) Development of infrared detection technology

In 2008, Yuan Hua and others conducted an analysis and research on infrared detection. It has excellent environmental adaptability and the advantages of small size and light weight, and it plays an excellent role in environmental issues, transportation issues, conference issues, conflict issues, armed conflict monitoring, and arms control. In order to meet the development needs of infrared detection in information collection technology, developed countries such as the United States are actively exploring spectral bands. and made great progress.

(2) Development of ultrasonic obstacle avoidance technology

In 2008, Borenstein J et al. developed a mobile robot system that can perform various tasks for the disabled. To avoid collisions with unexpected obstacles, mobile robots use ultrasonic range finders for detection and mapping. The robot's obstacle avoidance strategy relies heavily on the performance of the ultrasonic range finder.

(3) Development of wireless transmission technology

In 2011, Zhao Han analyzed the development of wireless transmission technology. The results show that with the advancement of human science, the application of wireless transmission technology is becoming more and more extensive, which usually consists of wireless base stations, wireless terminals and corridor management servers. Today, wireless transmission technology is mainly used in mobile communication, Bluetooth technology and wireless broadband.

(4) Development of GPS technology

In 2012, the United States successfully launched its third GPS IIF satellite, a step forward in its satellite constellation modernization program. Simultaneously with the launch of the GPS IIF satellites, the development and production of the new generation of GPS IIIA navigation satellites and the modernization of the ground segment are also underway. With the improvement of GPS navigation accuracy and the expansion of application scope, GPS is still the "big brother" in the field of global satellite navigation.

(5) Development of Mecanum Wheel

Based on the omnidirectional movement performance of the mecanum wheel, the main body can move in any direction, so it has considerable application prospects in the field of manufacturing and warehousing logistics automation. In 2013, Chen Boweng and others proposed a feasible wheel design method and manufacturing process, and based on the omni-directional mobile platform of the Mecanum wheel, the kinematics and theoretical model provided a theoretical basis for the control algorithm, and carried out independent design and development.

1.2 Development Status of Smart Walking Sticks at Home and Abroad

In 2011, Romteera Khlaikhayai et al. proposed a new concept—a walking stick for the elderly and the blind, which is composed of wireless sensors and can be used for safe navigation. The wireless sensors contain an ad hoc network that can be implemented within the cane to provide group communication between them and provide navigation information and networking. The advantage of this system is that it can provide safety protection for the elderly and the blind, and it can implement and realize special activities such as blind assemblies and disabled people's networks.

In 2015, Zhou Peng and others developed a multifunctional smart cane based on the combination of ultrasonic ranging technology and digital display function, as well as voice prompt function, which can display the distance between the current cane and the obstacle in front in real time. distance to the user of the cane. The cane is composed of three main modules: ultrasonic module, control processing module and information output module. The cane distance measurement only needs to be within a distance of 300 millimeters, and the error is about 2 millimeters.

In 2016, Kher Chaitrali and others proposed a navigation device for the visually impaired. The navigation device mainly uses infrared sensing technology, radio frequency identification technology and Android devices to provide voice output for obstacle prevention and navigation. The navigation device features proximity infrared sensors, RFID tags are installed in public buildings and on the blind's canes, and an app is designed for family members to access the location of the blind through a server when needed.

In 2017, Li Ke and others developed a multi-functional smart cane. The cane includes a handle part and a main part. There is a button on the handle, and a searchlight controlled by the button is embedded in the front end of the handle; a near-infrared blood glucose detection device is installed in the upper part of the front of the handle. , The middle part of the handle is provided with a hole for detecting blood pressure, and the handle is equipped with a battery box for powering electrical devices; the handle has a built-in GPS signal receiver and a microprocessor. The invention is equipped with a front searchlight, which can provide lighting functions; the rod body is designed as a telescopic rod, which can adjust the length of the rod body; it is equipped with a medicine box, which is convenient and beautiful; the connection built by the handle on the satellite positioning can detect the position of the blind at any time.

At present, the research on smart canes at home and abroad has been relatively in-depth, and there have been many canes with various functions. The more mature ones should be Fujitsu's new multi-functional smart canes. If the distance is less than 130 cm, the voice broadcast function of the cane will automatically broadcast the obstacle distance to remind the blind to pay attention to safety. You can broadcast the current direction, real-time time and send text messages for help by pressing the buttons. Connecting to the computer system can detect and view the current geographical location of the smart cane, and gives the relevant user's life characteristics, and can also provide the user's family and health data. If any problems are detected, the smart stick will automatically turn on emergency services and location guidance. The handle is equipped with GPS positioning module, 3G communication module and wireless network module. These features are designed to solve the problem of getting lost for middle-aged, elderly or visually impaired people.

Twenty-seven percent of the population in Japan is over 65 years old, and it is currently the country with the most aging population in the world. China is 11%, ranking tenth, and technology products for the elderly are equally important for the domestic market. Therefore, this article aims to retain the basic functions of the smart cane while innovating. The design and use cost is low, easy to promote, and has high commercial and social value.

Contents of the invention

In order to provide a full range of intelligent services for the blind to travel, the present invention proposes an intelligent blind-guiding cane and a control method. The cane and the method integrate functions such as GPS positioning, wireless call for help, infrared tracking, ultrasonic obstacle avoidance, etc., to facilitate the travel of the blind , to provide security, intelligence, and high-quality protection.

The technical solution is as follows:

An intelligent blind guide cane, comprising: a handle, a cane bracket, a connection box, a bottom wheel, and a control system, the handle is connected to the connection box through the cane bracket, the connection box is connected to the bottom wheel, and the control system The system is set in one or more of the handle, cane support, and connection box, and the control system includes: a main controller, a GPS positioning system, an infrared tracking system, a fall detection system, an ultrasonic barrier system, a voice Broadcasting system, power supply system, wireless transmission system, the main controller is respectively connected with the GPS positioning system, infrared tracking system, fall detection system, ultrasonic obstacle shielding system, voice broadcast system, power supply system, wireless transmission system.

Further, it also includes a two-dimensional code recognition system, a fault detection system, and an environment mode switching system, and the two-dimensional code recognition system, the fault detection system, and the environment mode switching system are all connected to the main controller.

Further, the ultrasonic obstacle shielding system includes two SSD-ME007TX ultrasonic ranging modules, and each SSD-ME007TX ultrasonic ranging module includes: an ultrasonic transmitter, a receiver and a controller, and the ultrasonic transmitter, receiver Connected with the controller; the infrared tracking system includes several infrared sensors and image recognition sensors, the infrared sensors are installed on the bottom wheel, and the image recognition sensors are installed at the connection between the handle and the cane support; The fall detection system includes a gyroscope and a pressure sensor, and the gyroscope and the pressure sensor are built into the cane support; the voice broadcast system is arranged at the connection between the handle and the cane support; the main controller is STM32f103zet6 controller; the power system is an LM2596 power module.

Further, the side of the bottom wheel close to the connection box is recessed downward, and the side away from the connection box protrudes upward.

Further, it also includes an infrared sensing lighting lamp installed on the connection box.

The present invention also includes a method for controlling an intelligent blind guide stick, comprising the following steps:

The ultrasonic obstacle avoidance system detects obstacles within 2cm to 3.5m around the cane, and gives voice prompts to obstacles entering the range. During the process of traveling, the GPS positioning system performs synchronous positioning, and the ultrasonic obstacle avoidance system detects the obstacles ahead. When there is an obstacle, the signal is transmitted to the GPS positioning system. The GPS positioning system plans a reasonable route in time according to the positioning situation, and then converts the geographical location and route information into a voice signal and transmits it to the voice module for voice broadcast prompts to guide the blind to move forward;

The infrared tracking system detects the reflected light of the blind road, the main controller receives different reflected light detection signals, and controls the forward direction of the car by processing the reflected light detection signals;

The gyroscope detects whether the cane is tilted, the pressure sensor detects the instantaneous impact force of the cane when it is under pressure, and combines the tilt angle and tilt speed of the gyroscope to judge whether the cane is placed or falls to the ground. If a fall is detected, send The signal is sent to the wireless transmission module, and the geographical location information is sent to the pre-set external receiving device in the form of a short message, and an automatic help call is performed in time.

Furthermore, the ultrasonic obstacle avoidance system performs a distance measurement every 50ms, and after the distance measurement is completed, the distance value is output in the form of a serial port; when no obstacle is detected in front, it continues to go straight; when an obstacle is detected in front, stop the rudder If there is no obstacle in the front, then continue to go straight; when there is an obstacle in the front, change the direction.

further,

When turning in a blind road: When turning left, the left side of the built-in motor of the blind guide stick vibrates strongly to indicate a left turn; when a right turn occurs, the right side of the built-in motor of the guide stick vibrates strongly to indicate a right turn ;

When the width and depth of the blind road increase, multiple fine adjustments are made by adjusting the two-wheel differential;

When encountering an intersection, the infrared sensor will turn on the zebra crossing recognition function. When the red sensor detects the white zebra crossing stripes on the ground, it will guide the blind to move forward from the zebra crossing;

When encountering a traffic light, the image recognition sensor is used. After the image captured by the sensor head passes through the lens, it is converted into an electrical signal through the light receiving element. The brightness and shape of objects; when the direction of travel is detected to be a red light, timely voice broadcasts will be made to remind the blind to stop and wait in place, and when the green light is detected, they will be prompted to continue moving forward; by defining the loop detection method, the number of seconds of the traffic light The information is stored, and the image information is processed through the camera. At this time, with the infrared sensor and the ultrasonic module, if it is a green light, it will be judged whether it can safely pass through the intersection in the remaining time; if it is a red light, the specific waiting time will be broadcast by voice; The camera analyzes moving vehicles and pedestrians in advance, and reports road condition information through voice broadcast in time.

Further, the infrared tracing steps are as follows:

S1. Initialize the task counter and set the initial value X;

S2. When the white line shifts to the right by ΔX, adjust the direction to the right, the right wheel decelerates, and the left wheel accelerates;

When the white line deviates to the left by ΔX, then adjust the direction to the left, the left wheel decelerates, and the right wheel accelerates;

S3. Determine whether the white line is in the middle, if yes, execute; if not, return to step S2.

Further, the fall detection steps are as follows:

T1. The gyroscope is powered on and vibrates;

T2. Detect whether the capacitance of the gyroscope changes;

T3. When the capacitance of the gyroscope changes, calculate the change value of the angular velocity;

T4. Determine whether the change in angular velocity exceeds 0.5πrad/s;

T5. If the change value of the angular velocity does not exceed 0.5πrad/s, trigger the mobile communication module to give an alarm.

The beneficial effects of the present invention are:

The intelligent blind guide stick described in the present invention is a multi-functional driven intelligent blind guide stick integrating functions such as GPS positioning, wireless call for help, infrared tracking, ultrasonic obstacle avoidance and the like. Starting from making a travel plan for the blind, the whole process of navigation and positioning, infrared tracing of the blind road during the trip, medium and long-distance ultrasonic obstacle avoidance, intimate voice and music broadcast function during the process, anti-lost and anti-fall reminders, intelligent call for help devices, automatic charging system, etc. It provides a comprehensive solution to the travel inconvenience of the blind. In a word, with a stick in hand, the whole journey is worry-free. It is convenient for the blind to travel and provides safe, intelligent and high-quality protection.

Description of drawings

Fig. 1 is a schematic diagram of the Fujitsu smart walking stick in the background technology;

Fig. 2 is a hardware function block diagram of the smart walking stick for the blind of the present invention;

Fig. 3 is the hardware circuit diagram of the SSD-ME007TX ultrasonic ranging module of the present invention;

Fig. 4 is the flow chart of ultrasonic obstacle avoidance of the present invention;

Fig. 5 is a hardware circuit diagram of the GPS navigation system of the present invention;

Fig. 6 is an overall structural diagram of the smart walking stick of the present invention;

Fig. 7 is a schematic diagram of the turning angle of the wheel of the present invention;

Fig. 8 is a flow chart of infrared tracking of the present invention;

Fig. 9 is a circuit diagram of infrared tracking hardware of the present invention;

Fig. 10 is a hardware circuit diagram of the fall detection system of the present invention;

Fig. 11 is a flowchart of the fall detection system of the present invention;

Fig. 12 is a structural diagram of the bottom wheel of the intelligent blind guide stick of the present invention;

Fig. 13 is a hardware circuit diagram of the power module of the present invention;

Fig. 14 is a schematic diagram of the input and output ports of the power supply of the present invention;

Fig. 15 is a circuit diagram of the MCU main control interface and each module interface of the present invention;

The reference signs in Fig. 6 are as follows: 1-handle, 2-cane support, 3-connection box, 4-bottom wheel, 5-voice broadcast system, 6-image recognition sensor, 7-gyroscope, 8-infrared sensor, 9 - Infrared sensor lighting.

Detailed ways

Below in conjunction with accompanying drawing 1-15, the intelligent guide stick and the control method are further described.

An intelligent blind guide cane, comprising: a handle 1, a cane support 2, a connection box 3, a bottom wheel 4, and a control system, the handle 1 is connected to the connection box 3 through the cane support 2, and the connection box 3 is connected to the connection box 3 The bottom wheel 4 is connected, and the control system is arranged in one or more of the handle 1, the cane support 2, and the connection box 3. The control system includes: a main controller, a GPS positioning system, and an infrared tracking system , a fall detection system, an ultrasonic barrier system, a voice broadcast system, a power supply system, and a wireless transmission system, the main controller is respectively connected with the GPS positioning system, an infrared tracking system, a fall detection system, an ultrasonic barrier system, Voice broadcast system, power supply system, wireless transmission system connection.

Further, it also includes a two-dimensional code recognition system, a fault detection system, and an environment mode switching system, and the two-dimensional code recognition system, the fault detection system, and the environment mode switching system are all connected to the main controller.

Further, the ultrasonic obstacle shielding system includes two HC-SR04 ultrasonic ranging modules, and each HC-SR04 ultrasonic ranging module includes: an ultrasonic transmitter, a receiver and a controller, and the ultrasonic transmitter, receiver connected to the controller.

Further, the side of the bottom wheel 4 close to the connection box 3 is recessed downward, and the side away from the connection box 3 protrudes upward.

Further, the infrared tracking system includes several infrared sensors 8 and image recognition sensors 6, the infrared sensors 8 are installed on the bottom wheel 4, and the image recognition sensors 6 are installed on the handle 1 and the cane support 2 Junction.

Further, the fall detection system includes a gyroscope 7 and a pressure sensor, and the gyroscope 7 and the pressure sensor are built in the cane support 2 .

Further, the voice announcement system 5 is arranged at the joint between the handle 1 and the cane support 2 .

Further, the main controller is an STM32f103zet6 controller.

Further, the power system is an LM2596 power module.

Further, it also includes an infrared sensing lighting lamp installed on the connection box.

1. Function introduction

The smart blind guide cane provides a full range of intelligent services for the blind to travel. The smart blind guide cane is a multi-functional drive smart blind guide cane that integrates GPS positioning, wireless call for help, infrared tracking, ultrasonic obstacle avoidance and other functions. . Starting from making a travel plan for the blind, the whole process of navigation and positioning, infrared tracing of the blind road during the trip, medium and long-distance ultrasonic obstacle avoidance, intimate voice and music broadcast function during the process, anti-lost and anti-fall reminders, intelligent call for help devices, automatic charging system, etc. It provides a comprehensive solution to the travel inconvenience of the blind. In a word, with a stick in hand, the whole journey is worry-free. It is convenient for the blind to travel and provides safe, intelligent and high-quality protection.

2. Intelligent blind guide stick includes the following functions

The smart blind guide stick uses STM32f103zet6 as the main controller, which integrates ultrasonic obstacle avoidance, infrared tracking system, GPS navigation and positioning system, environmental mode switching system, voice broadcast system, fall detection system, wireless transmission system and fault diagnosis system power module system, etc., the hardware function block diagram of the intelligent guide cane of the system is shown in Figure 2.

1. Obstacle avoidance function:

The blind guide cane uses an ultrasonic sensor array to detect obstacles within 2cm to 400cm around the cane, and gives voice prompts to obstacles entering the range. The ultrasonic ranging module is HC-SR04, which can provide 2CM-400CM non-contact distance sensing function, and the ranging accuracy can reach as high as 3mm, including ultrasonic transmitter, receiver and control circuit. The working principle of this module is: connect power and ground to the ultrasonic module. Input a high-level square wave with a length of 20us to the pulse trigger pin (trig); after inputting the square wave, the module will automatically emit eight 40KHz sound waves, and at the same time the level of the echo pin (echo) will change from 0 Change to 1; (at this time, the timer should be started for timing). When the ultrasonic return is received by the module, the level of the echo pin will change from 1 to 0; (the timer should stop counting at this time), and the time recorded by the timer is the total time from the ultrasonic wave to its return. . According to the speed of sound in the air is 344 m/s, the measured distance can be calculated.

After the distance measurement is completed, the distance value is output in the form of a serial port. By setting the height and angle of the ultrasonic obstacle avoidance module, the blind can effectively avoid obstacles such as vehicles and street lights in front of them during the forward process. Synchronous positioning, after the ultrasonic probe finds an obstacle ahead, the signal is transmitted to the GPS system in time, and the GPS plans a reasonable route in time according to the positioning situation, and then converts the geographical location and route information into voice signals and transmits them to the voice module for voice broadcast prompts. Guide the blind. The hardware circuit diagram of the ultrasonic obstacle avoidance system is shown in Figure 4. The main procedures of the ultrasonic obstacle avoidance system are as follows:

2. Navigation and positioning

The navigation and positioning system of the intelligent guide cane adopts the GPS navigation of the Global Positioning System (GLOBAL POSITIONING SYSTEM).

Navigation function and path planning:

Install the voice assistant on the cane terminal, you can voice input the target location, determine the target location, optimize and select the route by the GPS navigation system, and at the same time perform voice broadcast prompts.

In terms of intelligent crutch route planning, the Dijkstra algorithm is used to find the shortest route. The Dijkstra algorithm is a greedy algorithm, which can be used to find the shortest path between two specified points, or the shortest path from a specified point to all other points. According to the initial point of the smart crutch, find the points closest to the initial point one by one and add them to the set. The d[i] of all points in the set is the shortest path length from this point to the initial point.

Set two vertex sets T and S. S stores the vertices that have found the shortest path. Initially, there is only one vertex in the set S, that is, the source point V0. T stores the vertices that have not yet found the shortest path, and then in the set T Select the shortest path (V0...Vk) with the shortest current length, so as to add Vk to the vertex set S, and modify the shortest path length from the far point V0 to each vertex in T; repeat this step, Until all points join S. In the program, dist[n]:dist[i] indicates the length of the shortest path from the source point V0 to the end point Vi currently found. When initializing, dist[i]=edge[v0][i], S[n ]: S[i] is 0, indicating that the vertex Vi has not been added to the set S, S[v0]=1 during initialization, and the rest are 0, path[n]:path[i] indicates the vertex on the shortest path from V0 to Vi The previous vertex number of Vi. Using the "backtracking" method, determine each vertex on the shortest path from V0 to Vi. The main procedure is as follows:

In this way, the previous point and the path of each road can be found through the edge. If the adjacency matrix is used to store it, the node u can be directly stored here.

GPS:

After the cane is powered on, the system will locate the cane in real time, and at the same time provide the cane location information sharing service, which can share the position of the cane with relatives and police officers, providing humanized anti-lost and anti-lost functions. GPS hardware circuit diagram shown in Figure 5.

3. Infrared tracking system

The system is based on infrared sensor tracking. Its working principle is that the yellow color of the blind road and the dark color of the pedestrian road form a large color difference. Due to the difference in the reflection intensity of the infrared light between the dark color and the light color, the sensor receives different reflections. Light detection signal, the controller of the blind guide cane realizes the control of the forward direction of the car by obtaining different level signals.

When the cane is working, the wheel at the lower end of the intelligent blind guide cane is designed as a groove structure with a depth of 5mm, so that the blind path and the wheel form a good embedded structure and run stably. The overall structure of the blind guide cane is shown in Figure 6.

Special case handling:

When making a blind turn:

When a left turn occurs, the built-in motor on the left side of the walking stick vibrates strongly to prompt a left turn.

When the blind road parameters change slightly:

When the parameters change slightly, such as the increase in the width and depth of the blind road, and the position adjustment, multiple fine adjustments are made by adjusting the differential speed of the two wheels.

When encountering a zebra crossing:

When encountering an intersection or a crossroad, the infrared sensor will turn on the zebra crossing recognition function. When the red sensor detects the white zebra crossing stripes on the ground, it will guide the blind to move forward from the zebra crossing.

OpenMV QR code recognition

The QR code recognition uses the OpenMV4 module. The OpenMV4 camera is a small, low-power, and low-cost circuit board, which helps you easily complete machine vision (machine vision) applications. Through high-level language Python scripts (MicroPython to be precise), not C/C++. Python's advanced data structure makes it easy for you to process complex output in machine vision algorithms, you can easily use external terminals to trigger shooting or execute algorithms, and you can also use the results of algorithms to control IO pins. Using OpenMV Cam to read the QR code in its field of view, through QR code detection/decoding, it can read the labels in the environment, and transmit the read QR code information to the main control (MCU) through the serial port The STM32 chip, according to the received different information, sends out different instructions to realize different functions of the crutch. The main procedure is as follows:

Traffic light recognition:

With the image recognition sensor, the image captured by the sensor head (camera) passes through the lens and is converted into an electrical signal through the light receiving element (CMOS imaging sensor). Then, the brightness and shape of the target are discriminated based on the shading and shade information assigned to the number of pixels of the light receiving element. The light receiving element is a color type. Unlike the black-and-white type that uses black and white bipolar grayscales for recognition, the received light information is analyzed into the three primary colors (RGB) and each grayscale is recognized, so even colors with little difference in shade can be distinguished.

When encountering an intersection with traffic lights, the cane will detect red lights and green lights in two directions, and judge the detected colors. After identifying the result, give the corresponding instructions to the processor. If the direction of travel is detected to be a red light, a voice broadcast will be made in time to prompt the blind person to stop and wait in place. By defining a loop detection method, the digital information of the number of seconds of the traffic light is stored, and the image information is processed through the camera. At this time, with the infrared sensor and the ultrasonic module, if the light is green, it is judged whether it can safely pass through the intersection in the remaining time. If it is a red light, the specific waiting time will be announced by voice. In addition, the camera analyzes moving vehicles and pedestrians in advance, and reports road condition information through voice broadcast in time.

The infrared tracking flow chart is shown in Figure 8, and the hardware circuit diagram is shown in Figure 9.

4. Fall detection system

The fall detection system, through the installed gyroscope 7 (model MPU6050), reads the three-axis angular velocity value and the three-axis acceleration value transmitted back from the MPU6050, and performs an algorithm analysis on the collected Z-axis acceleration and angular velocity. When the Z-axis acceleration When the value and the angular velocity value suddenly increase to the set predetermined value, it is judged that the blind man holding the cane has fallen down. Set the acceleration full scale to ±4g. When the acceleration value of the Z axis reaches ±2g and the deflection angle calculated by the angular velocity reaches ±45°, the voice broadcast will ask if you have fallen. When the acceleration value and the deflection angle value exceed this value at the same time , immediately judge whether it has fallen.

If it is determined to fall, it will send an alarm in time, touch the mobile communication module, and send the location information to the pre-set external receiving device in the form of a short message, and automatically call for help in time, so that the blind person who fell can be in the first place. receive help. The circuit of the fall detection system is shown in Figure 9, and the program block diagram is shown in Figure 10.

The main procedures of fall detection gyroscope and accelerometer are as follows:

5. Voice broadcast

The voice broadcast system needs to cover all the functional systems in the connected cane. It can perform voice broadcast on the road conditions during the driving process, provide direction guidance for the forward route when obstacles in front are detected, and monitor the power of the cane in real time. voice alarm. At the same time, the voice system is equipped with a Bluetooth module, which can be connected to the headset through Bluetooth, so that the blind can receive information in time.

6. Movement system

According to the analysis of the following characteristics of the blind passage, the blind guide strips on the blind passage are 5mm above the ground, and the default blind passage strips are parallel to each other with equal spacing. The wheel structure as shown in Figure 12 is designed, which is similar to the wheels of the train, and can run stably on the blind curb similar to the train track. The contact between the wheel and the blind curb is an inclined contact, which reduces most of the sand and stones. The impact of walking with a blind cane improves the tracking accuracy.

The two-wheel differential movement method is used to realize the turning. When the blind guide cane moves forward, the two wheels rotate counterclockwise, and when it moves backward, the two wheels rotate clockwise.

To sum up the solution of the motion system: the two motors use Hall DC encoder motors, through the encoder mode of the main control STM32 timer, the M method is used to measure the speed, and the value of the motor encoder is read every 10ms, that is, detected High level time, you can calculate the speed of each wheel, calculate the encoder value obtained each time, and use the obtained speed as the actual value Encoder for incremental PID adjustment, and then do it with the actual value Target you want The deviation can be obtained by calculating the current variation Bias, the cumulative deviation Integral _bias , and the last deviation Last _bias , and then through the incremental PID control formula:

PWM _Δ ＝K _p *Bias+K _i *Intergral _bias +K _d *(Bias-Last _bias ) (1)

Get the target speed PWM of the motor, and then assign the corresponding PWM to the motor through STM32 to ensure that the two motors maintain the same speed in the process of going straight. When it is necessary to turn or track deviation, through the two-wheel differential method, change the speed of one motor to realize turning or adjustment, such as: when turning left, increase the target value Target of the right wheel motor, appropriate Reduce the target value of the left wheel motor, so as to achieve the purpose of turning or adjustment.

The differential speed control procedure is as follows:

7. Fault detection system

Diagnose whether each sensor is working normally by setting up a diagnostic program, and combine the knowledge reasoning of the trained neural network to analyze and detect the fault, broadcast the fault through the voice assistant, and transmit the location information and fault information through the communication module. To the emergency contacts set in advance.

8. Environment mode switching system

When a blind person needs to go to a public place such as a supermarket or a hospital, the artificial intelligence assistant will automatically identify the destination and switch the corresponding mode. The side shelf is detected to ensure that blind people can walk safely in the aisle of the shelf. At the same time, the two-dimensional code recognition module is turned on. By analyzing the two-dimensional code of the product on the shelf, the category of the product is judged, and then image recognition is performed. Through The internal neural network analyzes specific commodities by connecting to the Internet, including basic information on prices and commodities. After the shopping is completed, the built-in display screen of the walking stick automatically displays the payment code to complete the payment.

9. Power module system

The power supply adopts LM2596 power supply module, which can almost reach 75% power supply efficiency in general practical operation, and the cost performance is relatively high. This experiment chooses LM2596 as the power module. Input voltage 7-·12V, output voltage 5V, output current 1A, built-in AC-DC power converter. At the same time, the power supply part of the system uses solar panels for power complementation. There are photosensitive elements around the solar panels. By judging the intensity of light, the solar panels rotate with the direction of light intensity to obtain the largest area of light. . The hardware circuit diagram of the power module is shown in Figure 13. The power supply has two interfaces, one interface can input and output 3.3 or 5V voltage. The schematic diagram of the power input and output ports is shown in Figure 14.

3. Overall hardware design

The MCU main control interface and each module interface circuit are shown in Figure 15.

Example 2

A method for controlling an intelligent blind guide stick, comprising the following steps:

The ultrasonic obstacle avoidance system detects obstacles within 2cm to 3.5m around the cane, and gives voice prompts to obstacles entering the range. During the process of traveling, the GPS positioning system performs synchronous positioning, and the ultrasonic obstacle avoidance system detects the obstacles ahead. When there is an obstacle, the signal is transmitted to the GPS positioning system. The GPS positioning system plans a reasonable route in time according to the positioning situation, and then converts the geographical location and route information into a voice signal and transmits it to the voice module for voice broadcast prompts to guide the blind to move forward;

The infrared tracking system detects the reflected light of the blind road, the main controller receives different reflected light detection signals, and controls the forward direction of the car by processing the reflected light detection signals;

The gyroscope detects whether the cane is tilted, the pressure sensor detects the instantaneous impact force of the cane when it is under pressure, and combines the tilt angle and tilt speed of the gyroscope to judge whether the cane is placed or falls to the ground. If a fall is detected, send The signal is sent to the wireless transmission module, and the geographical location information is sent to the pre-set external receiving device in the form of a short message, and an automatic help call is performed in time.

Furthermore, the ultrasonic obstacle avoidance system performs a distance measurement every 50ms, and after the distance measurement is completed, the distance value is output in the form of a serial port; when no obstacle is detected in front, it continues to go straight; when an obstacle is detected in front, stop the rudder If there is no obstacle in the front, then continue to go straight; when there is an obstacle in the front, change the direction.

further,

When turning in a blind road: When turning left, the left side of the built-in motor of the blind guide stick vibrates strongly to indicate a left turn; when a right turn occurs, the right side of the built-in motor of the guide stick vibrates strongly to indicate a right turn ;

When the width and depth of the blind road increase, multiple fine adjustments are made by adjusting the two-wheel differential;

When encountering an intersection, the infrared sensor will turn on the zebra crossing recognition function. When the red sensor detects the white zebra crossing stripes on the ground, it will guide the blind to move forward from the zebra crossing;

When encountering a traffic light, the image recognition sensor is used. After the image captured by the sensor head passes through the lens, it is converted into an electrical signal through the light receiving element. The brightness and shape of objects; when the direction of travel is detected to be a red light, timely voice broadcasts will be made to remind the blind to stop and wait in place, and when the green light is detected, they will be prompted to continue moving forward; by defining the loop detection method, the number of seconds of the traffic light The information is stored, and the image information is processed through the camera. At this time, with the infrared sensor and the ultrasonic module, if it is a green light, it will be judged whether it can safely pass through the intersection in the remaining time; if it is a red light, the specific waiting time will be broadcast by voice; The camera analyzes moving vehicles and pedestrians in advance, and reports road condition information through voice broadcast in time.

Further, the infrared tracing steps are as follows:

S1. Initialize the task counter and set the initial value X;

S2. When the white line shifts to the right by ΔX, adjust the direction to the right, the right wheel decelerates, and the left wheel accelerates;

When the white line deviates to the left by ΔX, then adjust the direction to the left, the left wheel decelerates, and the right wheel accelerates;

S3. Determine whether the white line is in the middle, if yes, execute; if not, return to step S2.

Further, the fall detection steps are as follows:

T1. The gyroscope is powered on and vibrates;

T2. Detect whether the capacitance of the gyroscope changes;

T3. When the capacitance of the gyroscope changes, calculate the change value of the angular velocity;

T4. Determine whether the change in angular velocity exceeds 0.5πrad/s;

T5. If the change value of the angular velocity does not exceed 0.5πrad/s, trigger the mobile communication module to give an alarm.

The above is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Anyone familiar with the technical field within the technical scope disclosed in the present invention, according to the technical solution of the present invention Any equivalent replacement or change of the inventive concepts thereof shall fall within the protection scope of the present invention.

Claims (10)

1. An intelligent guide stick for the blind, comprising: a handle (1), a stick support (2), a connection box (3), a bottom wheel (4), a control system, and the handle (1) passes through the stick support (2) Connected with the connection box (3), the connection box (3) is connected with the bottom wheel (4), the control system is arranged on the handle (1), the cane support (2), the connection In one or more of the boxes (3), the control system includes: a main controller, a GPS positioning system, an infrared tracking system, a fall detection system, an ultrasonic barrier system, a voice broadcast system, a power supply system, a wireless transmission system, the main controller is respectively connected with the GPS positioning system, infrared tracking system, fall detection system, ultrasonic obstacle shielding system, voice broadcast system, power supply system, and wireless transmission system. 2. The intelligent guide stick for the blind as claimed in claim 1, further comprising a two-dimensional code recognition system, a fault detection system, and an environmental mode switching system, and the two-dimensional code recognition system, a fault detection system, and an environmental mode switching system The systems are all connected to the main controller. 3. The intelligent blind guide stick according to claim 1, wherein the ultrasonic barrier system includes two SSD-ME007TX ultrasonic ranging modules, and each SSD-ME007TX ultrasonic ranging module includes: an ultrasonic transmitter , receiver and controller, described ultrasonic transmitter, receiver are connected with described controller; Described infrared tracing system comprises several infrared sensors (8) and image recognition sensor (6), and described infrared sensor (8) Installed on the bottom wheel (4), the image recognition sensor (6) is installed at the joint between the handle (1) and the cane support (2); the fall detection system includes a gyroscope (7), a pressure The sensor, the gyroscope (7) and the pressure sensor are built in the cane support (2); the voice broadcast system (5) is arranged at the connection between the handle (1) and the cane support (2); the The main controller is the STM32f103zet6 controller; the power system is the LM2596 power module. 4. The intelligent walking stick for the blind according to claim 1, characterized in that, the bottom wheel (4) is recessed on the side of the connection box (3), away from the side of the connection box (3) Protrude upwards. 5. The intelligent walking stick for blindness according to claim 1, characterized in that it further comprises an infrared sensing lighting lamp (9), and the infrared sensing lighting lamp (9) is installed on the connection box (3). 6. An intelligent blind-guiding stick control method, comprising the following steps: The ultrasonic obstacle avoidance system detects obstacles within 2cm to 3.5m around the cane, and gives voice prompts to obstacles entering the range. During the process of traveling, the GPS positioning system performs synchronous positioning, and the ultrasonic obstacle avoidance system detects the obstacles ahead. When there is an obstacle, the signal is transmitted to the GPS positioning system. The GPS positioning system plans a reasonable route in time according to the positioning situation, and then converts the geographical location and route information into a voice signal and transmits it to the voice module for voice broadcast prompts to guide the blind to move forward; The infrared tracking system detects the reflected light of the blind road, the main controller receives different reflected light detection signals, and controls the forward direction of the car by processing the reflected light detection signals; The gyroscope detects whether the cane is tilted, the pressure sensor detects the instantaneous impact force of the cane when it is under pressure, and combines the tilt angle and tilt speed of the gyroscope to judge whether the cane is placed or falls to the ground. If a fall is detected, send The signal is sent to the wireless transmission module, and the geographical location information is sent to the pre-set external receiving device in the form of a short message, and an automatic help call is performed in time. 7. The intelligent blind-guiding cane control method as claimed in claim 6, wherein the ultrasonic obstacle avoidance system performs a distance measurement every 50 ms, and after the distance measurement is completed, the distance value is output in the form of a serial port; when it is detected that there is no obstacle ahead When an obstacle is detected in front, continue to go straight; when an obstacle is detected in front, stop the steering gear and change direction; detect after changing direction, when no obstacle is detected in front, continue to go straight; when an obstacle is detected in front, change direction . 8. The intelligent blind-guiding cane control method as claimed in claim 6, characterized in that, When turning in a blind road: When turning left, the left side of the built-in motor of the blind guide stick vibrates strongly to indicate a left turn; when a right turn occurs, the right side of the built-in motor of the guide stick vibrates strongly to indicate a right turn ; When the width and depth of the blind road increase, multiple fine adjustments are made by adjusting the two-wheel differential; When encountering an intersection, the infrared sensor will turn on the zebra crossing recognition function. When the red sensor detects the white zebra crossing stripes on the ground, it will guide the blind to move forward from the zebra crossing; When encountering a traffic light, the image recognition sensor is used. After the image captured by the sensor head passes through the lens, it is converted into an electrical signal through the light receiving element. The brightness and shape of objects; when the direction of travel is detected to be a red light, timely voice broadcasts will be made to remind the blind to stop and wait in place, and when the green light is detected, they will be prompted to continue moving forward; by defining the loop detection method, the number of seconds of the traffic light The information is stored, and the image information is processed through the camera. At this time, with the infrared sensor and the ultrasonic module, if it is a green light, it will be judged whether it can safely pass through the intersection in the remaining time; if it is a red light, the specific waiting time will be broadcast by voice; The camera analyzes moving vehicles and pedestrians in advance, and reports road condition information through voice broadcast in time. 9. The intelligent blind-guiding cane control method as claimed in claim 6, wherein the infrared tracing step is as follows: S1. Initialize the task counter and set the initial value X; S2. When the white line shifts to the right by ΔX, adjust the direction to the right, the right wheel decelerates, and the left wheel accelerates; When the white line deviates to the left by ΔX, then adjust the direction to the left, the left wheel decelerates, and the right wheel accelerates; S3. Determine whether the white line is in the middle, if yes, execute; if not, return to step S2. 10. The intelligent blind-guiding cane control method as claimed in claim 6, characterized in that the fall detection step is as follows: T1. The gyroscope is powered on and vibrates; T2. Detect whether the capacitance of the gyroscope changes; T3. When the capacitance of the gyroscope changes, calculate the change value of the angular velocity; T4. Determine whether the change in angular velocity exceeds 0.5πrad/s; T5. If the change value of the angular velocity does not exceed 0.5πrad/s, trigger the mobile communication module to give an alarm.