阅读说明：本技术 基于声波反射强度分析的草地识别方法 (Grassland identification method based on sound wave reflection intensity analysis ) 是由 不公告发明人 于 2020-03-20 设计创作，主要内容包括：本发明公开一种基于声波反射强度分析的草地识别方法,包括运动平台,设置在内部的处理器,运动平台底部安装超声波收发模块,超声波收发模块连接信号驱动电路和信号放大电路,信号驱动电路和信号放大电路连接处理器,处理器内部设置草地识别算法,包括以下步骤：(1)处理器每隔固定时间,通过信号驱动电路和超声波收发模块发射超声波,超声波收发模块接收超声波反射信号,经过信号放大电路以后输出给处理器,处理器将信号放大电路输出信号经过AD采样转换为数字信号f(t)；(2)比较出数字信号f(t)的最大值Fmax；(3)如果最大值Fmax<K,则判断为草地；否则,则判断为非草地。(The invention discloses a grassland identification method based on sound wave reflection intensity analysis, which comprises a motion platform and a processor arranged in the motion platform, wherein an ultrasonic transceiver module is arranged at the bottom of the motion platform and is connected with a signal driving circuit and a signal amplifying circuit, the signal driving circuit and the signal amplifying circuit are connected with the processor, and a grassland identification algorithm is arranged in the processor, and the grassland identification method comprises the following steps: (1) the processor transmits ultrasonic waves through the signal driving circuit and the ultrasonic wave receiving and transmitting module at fixed time intervals, the ultrasonic wave receiving and transmitting module receives ultrasonic wave reflection signals, the ultrasonic wave reflection signals are output to the processor after passing through the signal amplifying circuit, and the processor converts signals output by the signal amplifying circuit into digital signals f (t) after AD sampling; (2) comparing the maximum value Fmax of the digital signal f (t); (3) if the maximum value Fmax is less than K, judging the lawn; otherwise, judging the lawn is not grassland.)

1. The grassland identification method based on the sound wave reflection intensity analysis comprises a motion platform capable of moving autonomously, wherein a processor is arranged in the motion platform, and the grassland identification method is characterized in that: the bottom of the motion platform is provided with an ultrasonic transceiver module, the ultrasonic transceiver module is connected with a signal driving circuit and a signal amplifying circuit, the signal driving circuit and the signal amplifying circuit are connected with the processor, a grassland identification algorithm is arranged in the processor to determine whether the position of the motion platform is grassland or not, and the grassland identification algorithm comprises the following steps:

(1) the processor transmits ultrasonic waves through the signal driving circuit and the ultrasonic wave transmitting and receiving module at fixed time intervals, the ultrasonic wave transmitting and receiving module receives ultrasonic wave reflection signals and outputs the ultrasonic wave reflection signals to the processor after the ultrasonic wave reflection signals pass through the signal amplifying circuit, and the processor converts signals output by the signal amplifying circuit into digital signals f (t) after AD sampling at an interval delta t after the ultrasonic wave signals are transmitted;

(2) comparing the maximum value Fmax of the digital signal f (t);

(3) if the maximum value Fmax is less than K, judging the lawn; otherwise, judging the lawn to be non-grassy, wherein K is an empirical threshold.

2. A method of grass identification based on analysis of the reflected intensity of sound waves as claimed in claim 1, characterized in that: the ultrasonic transceiver module is arranged into an ultrasonic transmitting probe and an ultrasonic receiving probe which are arranged side by side.

3. A method of grass identification based on analysis of the reflected intensity of sound waves as claimed in claim 1, characterized in that: the ultrasonic transceiver module is arranged as an ultrasonic probe integrating receiving and transmitting.

4. A grass identification method based on analysis of the reflected intensity of sound waves according to claims 1 and 3, characterized in that: the ultrasonic transceiver module is provided with a multi-way switch, the common end of the multi-way switch is connected with the ultrasonic probe, the input end of the multi-way switch is connected with the signal driving circuit, the output end of the multi-way switch is connected with the signal amplifying circuit, and the control end of the multi-way switch is connected with the processor.

Technical Field

The patent relates to a grassland identification method based on sound wave reflection intensity analysis, and belongs to the technical field of mobile robots.

Background

The mowing robot is an automated device that works on a lawn, keeps the lawn neat and uniform in height, and only needs occasional manual intervention, without posing a threat to the lawn and itself. The mowing robot must therefore be able to determine its own working area accurately and reliably, preventing border crossings and causing unexpected risks. While the greatest feature of lawns is green grass, the grass identification method is therefore spread around the grass. The existing method is based on the detection of the conductive characteristic, two electrodes are arranged at the bottom of the mowing robot, and when the mowing robot is on a lawn, blades of grass have certain conductivity due to the fact that the blades contain moisture and have obvious conductive characteristics relative to air. However, this method fails to detect sparse or overly dry lawns.

Disclosure of Invention

Aiming at the problems, the lawn recognition method based on the sound wave reflection intensity analysis is provided by adopting a sound wave reflection intensity method, and the lawn recognition is carried out according to the obvious difference of the lawn and the common ground on the ultrasonic wave reflection characteristics.

The technical scheme adopted by the patent for solving the technical problem is as follows:

the grassland identification method based on the sound wave reflection intensity analysis comprises a motion platform capable of moving autonomously, a processor is arranged in the motion platform, an ultrasonic transceiver module is installed at the bottom of the motion platform and is connected with a signal driving circuit and a signal amplifying circuit, the signal driving circuit and the signal amplifying circuit are connected with the processor, a grassland identification algorithm is arranged in the processor and is used for determining whether the position of the motion platform is grassland or not, and the grassland identification algorithm comprises the following steps:

(1) the processor transmits ultrasonic waves through the signal driving circuit and the ultrasonic wave transmitting and receiving module at fixed time intervals, the ultrasonic wave transmitting and receiving module receives ultrasonic wave reflection signals and outputs the ultrasonic wave reflection signals to the processor after the ultrasonic wave reflection signals pass through the signal amplifying circuit, and the processor converts signals output by the signal amplifying circuit into digital signals f (t) after AD sampling at an interval delta t after the ultrasonic wave signals are transmitted;

(2) comparing the maximum value Fmax of the digital signal f (t);

(3) if the maximum value Fmax is less than K, judging the lawn; otherwise, judging the lawn to be non-grassy, wherein K is an empirical threshold.

The ultrasonic transceiver module is arranged into an ultrasonic transmitting probe and an ultrasonic receiving probe which are arranged side by side.

The ultrasonic transceiver module is arranged as an ultrasonic probe integrating receiving and transmitting.

The ultrasonic transceiver module is provided with a multi-way switch, the common end of the multi-way switch is connected with the ultrasonic probe, the input end of the multi-way switch is connected with the signal driving circuit, the output end of the multi-way switch is connected with the signal amplifying circuit, and the control end of the multi-way switch is connected with the processor.

The beneficial effect of this patent mainly shows: by adopting the method of the sound wave reflection intensity, the grassland is identified by the obvious difference of the reflection characteristics of the grassland and the common ground to the ultrasonic wave, and the reliability is high.

Drawings

FIG. 1 is a functional block diagram of a first embodiment;

FIG. 2 is a lawn reflection signal;

FIG. 3 is a ground reflected signal;

fig. 4 is a schematic block diagram of the second embodiment.

Detailed Description

The invention is further described below with reference to the accompanying drawings:

referring to fig. 1-3, the first embodiment of this patent:

the grassland identification method based on the sound wave reflection intensity analysis comprises a motion platform capable of moving automatically, wherein the motion platform can be provided with a driving wheel and a supporting wheel, and can realize straight movement, backward movement and rotation at any angle. The motion platform inside set up treater 1, carry out centralized control, motion platform bottom installation ultrasonic transceiver module 2, ultrasonic transceiver module 2 set up to ultrasonic emission probe and the ultrasonic receiving probe who places side by side. Therefore, a signal driving circuit 3 is provided, the output end of which is connected with the ultrasonic transmitting probe, the input end of which is connected with the processor, and a signal amplifying circuit 4 is provided, the input end of which is connected with the ultrasonic receiving probe, and the output end of which is connected with the processor 1.

A grassland recognition algorithm is arranged in the processor 1 to determine whether the position of the motion platform is grassland or not, and the grassland recognition algorithm comprises the following steps:

(1) the processor 1 transmits ultrasonic waves through the signal driving circuit 3 and the ultrasonic wave transceiving module 2 at fixed time intervals, the ultrasonic wave transceiving module 2 receives ultrasonic wave reflection signals and outputs the ultrasonic wave reflection signals to the processor 1 after passing through the signal amplifying circuit 4, and the processor 1 converts signals output by the signal amplifying circuit 4 into digital signals f (t) after AD sampling at an interval of delta t after the ultrasonic wave signals are transmitted;

the processor 1 performs signal sampling after an interval of Δ t, so as to avoid direct interference of the ultrasonic transmitting probe to the ultrasonic receiving probe in the ultrasonic transceiver module 2, instead of reflected signals.

(2) Comparing the maximum value Fmax of the digital signal f (t);

the digital signal f (t) is a periodic attenuation signal, the maximum value of the periodic attenuation signal represents the emission coefficient of the reflecting surface, and the reflection coefficient reflects the characteristics of the reflecting surface, namely, the ground reflection coefficient is large, the grass reflection coefficient is small, and based on the characteristics, the grass can be distinguished from the common ground.

(3) If the maximum value Fmax is less than K, judging the lawn; otherwise, judging the lawn to be non-grassy, wherein K is an empirical threshold.

And taking the maximum value Fmax as a judgment basis.

As shown in fig. 4, the second embodiment of the present patent:

the difference from the first embodiment is that:

the ultrasonic transceiver module 2 is arranged as an ultrasonic probe integrating receiving and transmitting. The ultrasonic probe can be used as an ultrasonic transmitting probe and an ultrasonic receiving probe. Cost and installation space can be saved.

In order to realize time-sharing multiplexing of ultrasonic wave transmission and reception, a multi-way switch 5 is arranged, the common end of the multi-way switch 5 is connected with the ultrasonic probe, the input end of the multi-way switch is connected with the signal driving circuit 3, the output end of the multi-way switch is connected with the signal amplifying circuit 4, the control end of the multi-way switch is connected with the processor 1, and the processor 1 can control the common end of the multi-way switch 5 to be connected with the input end for ultrasonic wave transmission or connected with the output end for ultrasonic wave reception.

Also in step (1) of the grass identification algorithm, the processor 1 samples signals after an interval of Δ t, in order to avoid the influence of the self-oscillation of the ultrasonic probe on signal acquisition.