Mobile chassis obstacle early warning system and early warning method based on ultrasonic sensor

Abstract

The invention relates to the technical field of obstacle early warning, in particular to a mobile chassis obstacle early warning system and early warning method based on an ultrasonic sensor, and the system comprises a data collection module which collects obstacle data by emitting ultrasonic waves and receiving feedback ultrasonic data; the data analysis module is used for screening the acquired data according to a preset measurement value range and acquiring distance information of the obstacle according to the screened data; the early warning module is used for judging whether the distance information is smaller than a preset threshold distance or not, and if yes, a stop instruction is sent out. Obstacles are detected based on the ultrasonic sensor, and the influence of illumination and weather conditions is effectively overcome; the communication delay of the ultrasonic sensor is compensated, errors are effectively reduced, and a method for integrating the speed of the mobile chassis in the communication delay process of the ultrasonic sensor is adopted, so that interpolation processing of the delay condition is realized, the delay problem is relieved, an emergency stop instruction is sent in time, and obstacles are effectively avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of obstacle warning, in particular to a mobile chassis obstacle warning system and a warning method based on an ultrasonic sensor. Background Art

[0002] Traditional mobile chassis obstacle warning systems usually use technologies such as cameras and lidar to detect the surrounding environment to help vehicles or robots avoid obstacles; however, these technologies have some limitations and are easily interfered by lighting and weather conditions, resulting in inaccurate detection; secondly, these traditional systems are usually complex and require a large number of sensors and advanced algorithms to implement, making the cost relatively high. Summary of the invention

[0003] In view of the problems in the prior art, the present invention provides a mobile chassis obstacle warning system and a warning method based on ultrasonic sensors. The specific technical solutions are as follows:

[0004] Mobile chassis obstacle warning system based on ultrasonic sensors, including:

[0005] Data acquisition module: collects obstacle data by emitting ultrasonic waves and receiving the feedback ultrasonic data;

[0006] Data analysis module: Filter the collected data through the preset measurement value range, and obtain the distance information of obstacles through the filtered data;

[0007] Early warning module: used to determine whether the distance information is less than the preset threshold distance. If so, a stop command is issued.

[0008] As a further technical solution of the present invention, the distance information of the obstacle is obtained by relying on the following formula:

[0009]

[0010] Where S is the distance between the carrier and the obstacle, and T is the duration of the high level of the reverberation.

[0011] As a further technical solution of the present invention, the preset threshold distance depends on the following formula:

[0012] S 阈 >V(t 1 +t 2 )

[0013] Among them, S 阈 is the preset threshold distance, V is the current speed of the mobile chassis, t 1 is the braking time required based on the current speed, t 2 It is the communication delay time.

[0014] As a further technical solution of the present invention, the data analysis module and the early warning module are further provided with:

[0015] Data processing module: obtains the distance between the mobile chassis and the obstacle at the current moment by interpolating the distance information of the obstacle.

[0016] As a further technical solution of the present invention, the distance information interpolation processing relies on the following formula:

[0017] d now =d last -cos(ω last Δt)v last t

[0018] Among them, d now is the distance of the obstacle at the current moment, d last is the distance of the obstacle at the last moment, ω last is the angular velocity of the mobile chassis at the last moment, v last is the linear velocity of the mobile chassis at the previous moment, and Δt is the time difference between the current moment and the previous moment.

[0019] The mobile chassis obstacle warning method based on ultrasonic sensors, according to the mobile chassis obstacle warning system based on ultrasonic sensors, has the following specific steps:

[0020] S1, collecting obstacle data at a certain frequency through ultrasonic waves, and generating several distance values ​​according to the distance formula between the carrier and the obstacle;

[0021] S4, interpolating the current time value according to the distance information, and checking whether the interpolated distance is less than a preset threshold distance, and if so, sending a stop signal.

[0022] As a further technical solution of the present invention, there is further provided between S1 and S4:

[0023] S3, determine whether the current time value is 0, if not, enter S4.

[0024] As a further technical solution of the present invention, there is further provided between S1 and S3:

[0025] S2, for two consecutive sets of distance values, determine whether the current time value is less than the previous time value, if so, enter S3.

[0026] The beneficial effects of the present invention are as follows:

[0027] (1) This application uses ultrasonic sensors to detect obstacles, effectively overcoming the influence of lighting and weather conditions, and has a simple structure and low cost.

[0028] (2) By compensating for the communication delay of the ultrasonic sensor, the error is effectively reduced. The method of integrating the speed of the mobile chassis during the communication delay of the ultrasonic sensor is adopted to realize interpolation processing of the delay situation, alleviate the delay problem, issue an emergency stop command in time, and effectively avoid obstacles. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 The schematic diagram of the process structure of the mobile chassis obstacle warning system based on ultrasonic sensors is shown. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solution and advantages of the embodiments of the present invention more clear, the technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments.

[0031] Embodiment 1

[0032] Traditional mobile chassis obstacle warning systems usually use technologies such as cameras and lidar to detect the surrounding environment to help vehicles or robots avoid obstacles; however, these technologies have some limitations and are easily interfered by lighting and weather conditions, resulting in inaccurate detection; secondly, these traditional systems are usually complex and require a large number of sensors and advanced algorithms to implement, making the cost relatively high.

[0033] In view of the above technical problems, this application provides a mobile chassis obstacle warning system based on ultrasonic sensors. Figure 1 The schematic diagram of the process structure of the mobile chassis obstacle warning system based on ultrasonic sensors is shown. It should be noted that the figure has A ultrasound, B ultrasound and C ultrasound as conventional options for this implementation. In some other embodiments, the number of ultrasounds is not limited. Therefore, the number of ultrasounds is also a limitation of this application. The mobile chassis obstacle warning system based on ultrasonic sensors includes:

[0034] Data acquisition module: used to collect obstacle data;

[0035] Obstacle data is collected by emitting ultrasonic waves and receiving feedback ultrasonic data;

[0036] Data analysis module: Filter the collected data through the preset measurement value range, and obtain the distance information of obstacles through the filtered data;

[0037] The distance information of the obstacle is obtained based on the following formula:

[0038]

[0039] Where S is the distance between the carrier and the obstacle, and T is the duration of the high level of the reverberation.

[0040] A range of measurement values ​​is preset according to the characteristics of ultrasonic obstacle determination, and values ​​that do not belong to the measurement range are filtered. For example, the longer the ultrasonic distance, the greater the measurement error. Therefore, values ​​exceeding 1m are filtered to avoid excessive values ​​affecting subsequent data processing.

[0041] By recording the time when the ultrasonic wave is emitted and the time when the ultrasonic wave is received as feedback, the distance between the carrier and the obstacle is calculated using the propagation speed of the ultrasonic wave in the air.

[0042] It can be seen from the above distance measurement formula that since the sound wave transmission takes time, and the mobile chassis does not stop moving during this process, there is a communication delay between the two, so the calculated distance information is not accurate enough;

[0043] Based on the above problems, the present application proposes a data processing module: by interpolating the distance information of the obstacle, the distance between the mobile chassis and the obstacle at the current moment is obtained;

[0044] The distance information interpolation process relies on the following formula:

[0045] d now =d last -cos(ω last Δt)v last t

[0046] Among them, d now is the distance of the obstacle at the current moment, d last is the distance of the obstacle at the last moment, ω last is the angular velocity of the mobile chassis at the last moment, v last is the linear velocity of the mobile chassis at the previous moment, and Δt is the time difference between the current moment and the previous moment.

[0047] By subtracting the distance traveled by the car within a certain period of time from the distance at the previous moment, the distance between the moving chassis and the obstacle at the current moment can be calculated, solving the communication delay problem of traditional ultrasonic sensors.

[0048] Early warning module: used to determine whether the distance information after interpolation processing is less than the preset threshold distance. If so, a stop command is issued;

[0049] The preset threshold distance depends on the following formula:

[0050] S 阈 >V(t 1 +t 2 )

[0051] Among them, S 阈 is the preset threshold distance, V is the current speed of the mobile chassis, t1 is the braking time required based on the current speed, t 2 It is the communication delay time.

[0052] The threshold distance of the dangerous obstacle distance is different according to the current speed of the mobile chassis. The faster the chassis speed, the longer it takes to decelerate. Let the time to decelerate to stop be t 1 , and there will be a communication delay when the chassis receives the emergency stop command. Let the communication delay time be t 2 , when the chassis moves forward at a speed V from the time the emergency stop command is issued to the time it stops completely, it will also move forward V (t 1 +t 2 ), then the set dangerous obstacle distance threshold must be greater than this distance, that is, S 阈 >V(t 1 +t 2 ) to overcome communication delays and ensure that the mobile chassis avoids obstacles.

[0053] Embodiment 2

[0054] The mobile chassis obstacle warning method based on ultrasonic sensor has the following specific steps:

[0055] S1, collecting obstacle data at a certain frequency through ultrasonic waves, and generating several distance values ​​according to the distance formula between the carrier and the obstacle;

[0056] S2, for two consecutive sets of distance values, determine whether the current time value is less than the previous time value, if so, enter S3;

[0057] S3, determine whether the current value is 0, if not, enter S4;

[0058] S4, interpolating the current time value according to the distance information, and checking whether the interpolated distance is less than a preset threshold distance, and if so, sending a stop signal.

[0059] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them.

Claims

1. The mobile chassis obstacle warning system based on ultrasonic sensors is characterized by: include: Data acquisition module: collects obstacle data by emitting ultrasonic waves and receiving the feedback ultrasonic data; Data analysis module: Filter the collected data through the preset measurement value range, and obtain the distance information of obstacles through the filtered data; Early warning module: used to determine whether the distance information is less than the preset threshold distance. If so, a stop command is issued.

2. The mobile chassis obstacle warning system based on ultrasonic sensors according to claim 1 is characterized in that: The distance information of the obstacle is obtained based on the following formula: S= 1 *340m / s 2T Where S is the distance between the carrier and the obstacle, and T is the duration of the high level of the reverberation.

3. The mobile chassis obstacle warning system based on ultrasonic sensors according to claim 1 is characterized in that: The preset threshold distance depends on the following formula: S 阈 >V(t1+t2) Among them, S 阈 is the preset threshold distance, V is the current speed of the mobile chassis, t1 is the braking time required based on the current speed, and t2 is the communication delay time.

4. The mobile chassis obstacle warning system based on ultrasonic sensors according to claim 3 is characterized in that: The data analysis module and the early warning module are further provided with: Data processing module: obtains the distance between the mobile chassis and the obstacle at the current moment by interpolating the distance information of the obstacle.

5. The ultrasonic sensor-based mobile chassis obstacle warning system according to claim 3, characterized in that: The distance information interpolation process relies on the following formula: d now =d last -cos(ω last Δt)v last t Among them, d now is the distance of the obstacle at the current moment, d last is the distance of the obstacle at the last moment, ω last is the angular velocity of the mobile chassis at the last moment, v last is the linear velocity of the mobile chassis at the previous moment, and Δt is the time difference between the current moment and the previous moment.

6. A mobile chassis obstacle warning method based on an ultrasonic sensor, according to the mobile chassis obstacle warning system based on an ultrasonic sensor according to any one of claims 1 to 5, characterized in that: The specific steps are as follows: S1, collecting obstacle data at a certain frequency through ultrasonic waves, and generating several distance values ​​according to the distance formula between the carrier and the obstacle; S4, interpolating the current time value according to the distance information, and checking whether the interpolated distance is less than a preset threshold distance, and if so, sending a stop signal.

7. The mobile chassis obstacle warning method based on ultrasonic sensors according to claim 6 is characterized in that: There is also between S1 and S4: S3, determine whether the current time value is 0, if not, enter S4.

8. The method for early warning of obstacles in a mobile chassis based on ultrasonic sensors according to claim 7, characterized in that: There is also between S1 and S3: S2, for two consecutive sets of distance values, determine whether the current time value is less than the previous time value, if so, enter S3.

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