CN111930106A - Mobile robot and control method thereof - Google Patents

Abstract

The invention provides a mobile robot and a control system thereof, wherein the mobile robot comprises a liftable laser radar and a binocular camera, the laser radar detects the distance from a barrier on a forward line to the mobile robot in an effective detection range of the laser radar and controls the laser radar to descend into a robot body, the binocular camera detects the minimum allowable passing height of the barrier after reaching the effective detection range and judges whether the barrier is allowed to pass, the laser radar and the binocular camera are matched with each other to ensure that the lifting time of the laser radar is determined in advance under the condition that the mobile robot does not need to decelerate or stop, and the barrier with height limitation is passed efficiently.

Description

Mobile robot and control method thereof

Technical Field

The invention relates to a mobile robot and a control method thereof, belonging to the field of household robots.

Background

Mobile robots for domestic use, typically including floor sweepers, mopping machines, mowers, etc., are becoming increasingly popular in modern life. In order to obtain better performance and better user experience, the arrangement of the liftable laser radar device on the mobile robot is the choice of more and more manufacturers, and the advantage is that even the liftable laser radar can be retracted into the robot body in a narrow space-limited area to reduce the overall height, so that the liftable laser radar device can smoothly pass through a barrier with limited height, and the laser radar device is prevented from being blocked.

In the prior art, an intelligent cleaning device is disclosed in CN108652532A, which discloses an optimized movement method for preventing jamming when contacting a high obstacle, but a significant technical solution is lacking for the control method of laser radar elevation, especially for the timing of elevation.

Disclosure of Invention

The invention provides a mobile robot and a control method thereof, which change the prior art that lifting control is determined only after physical collision with an obstacle by determining the lifting time in advance under the combined action of a binocular camera and a laser radar.

The solution proposed by the invention is as follows: a control method of a mobile robot with a liftable laser radar on the top comprises the following steps: detecting the distance from an obstacle on the forward route to the mobile robot through the laser radar, and if the distance is less than the distance L1, controlling the laser radar to retract into the body of the mobile robot; detecting the minimum height of an obstacle on a forward route through a binocular camera, if the minimum height is greater than a distance L2, controlling the mobile robot to run through the obstacle along the current direction, and otherwise, controlling to execute an avoidance action; the distance L1 is the speed of the mobile robot multiplied by the time of the laser radar shrinking into the mobile robot body, and the distance L2 is the height of the mobile robot after the laser radar shrinks into the mobile robot body.

Furthermore, the laser radar is a linear laser radar which can be rotatably installed on the mobile robot and comprises a transmitting end and a receiving end, wherein the transmitting end and the receiving end are close to the top end of the laser radar.

Furthermore, the binocular camera is an image sensor and is fixedly installed in the advancing direction of the mobile robot, and the two cameras are located at the same horizontal position.

Further, the binocular camera comprises an image processing module for processing the acquired image information.

Further, the binocular camera system further comprises an image processing module which is independently arranged in the mobile robot or the server and is indirectly or directly connected with the binocular camera through a wireless communication system.

Further, the avoidance operation includes turning, reversing, or stopping of the robot.

Further, after laser radar contracts to the mobile robot body, when binocular camera detected that the space height that can pass is greater than the total height of mobile robot when laser radar rose, the mobile robot was at least along the way distance D when passing through the barrier, and distance D is the linear distance of mobile robot front end to the laser radar end.

The invention also provides a mobile robot, which comprises a robot body, a liftable laser radar and a binocular camera, wherein when the distance from a barrier on a forward line detected by the laser radar to the mobile robot is less than L1, the barrier is retracted into the mobile robot body; when the binocular camera detects that the minimum height between the obstacle on the forward route and the ground is less than the distance L2, the mobile robot is controlled to execute the avoidance action; the distance L1 is the speed of the mobile robot multiplied by the time of the laser radar shrinking into the mobile robot body, and the distance L2 is the height of the mobile robot after the laser radar shrinks into the mobile robot body.

The invention has the beneficial effects that: the laser radar detects the distance from the barrier located on the forward route to the mobile robot in the effective detection range of the laser radar and controls the laser radar to descend to the robot body, the binocular camera detects the minimum height of the barrier allowed to pass after the binocular camera reaches the effective detection range and judges whether the barrier is allowed to pass, the mutual cooperation of the laser radar and the binocular camera enables the mobile robot to determine the lifting opportunity of the laser radar in advance under the condition of not reducing speed or stopping, and the barrier with height limitation is efficiently passed through.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required in the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it should be obvious for those skilled in the art that other embodiments obtained by the drawings should be included in the technical solutions of the present invention without creative efforts.

FIG. 1 is a schematic view of the construction of the present invention;

FIG. 2 is a signal logic diagram of the present invention;

fig. 3 is a schematic view of the mobile robot in embodiment 1 before detecting an obstacle;

FIG. 4 is a schematic view of a first state of embodiment 1;

FIG. 5 is a diagram showing a second state of embodiment 1;

FIG. 6 is a schematic view showing a third state of embodiment 1;

FIG. 7 is a schematic view showing a fourth state of embodiment 1;

fig. 8 is a state diagram of embodiment 2.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiment is only one embodiment of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example 1

As shown in fig. 1, the mobile robot includes a laser radar 1, a binocular camera 2 and a robot body 3, where the binocular camera 2 includes a first camera 201 and a second camera 202, and the cameras are different names of image capturing devices, and may be functional modules packaged by a CCD or a CMOS or other similar photosensitive elements. As shown in fig. 2, the signal direction of the mobile robot is shown, the first information M1 is distance sampling information obtained by the laser radar 1, and the laser radar 1 adopts a two-dimensional linear radar rotatably mounted on the mobile robot and can detect an obstacle signal at the same height as the radar within an effective detection range; second information M2 acquired by the binocular camera 2 is transmitted to the controller, the second information M2 is obtained through calculation of an image processing module, and the image processing module is integrated in the binocular camera so as to process data information in real time; the third information M3 is a lifting control signal sent by the controller to the laser radar 1. The preferred scheme can also include signals obtained by other external sensors as reference signals, such as infrared sensors, ultrasonic sensors and the like. In a preferred scheme, the image processing module can be independently arranged in the mobile robot or a remote server (a physical server or a cloud server), and is indirectly or directly connected with the binocular camera 2 through a wireless communication system so as to interact signals. According to the optimal scheme, the laser radar is provided with the data processing module, the lifting signal can be directly sent to the controller, and the binocular camera is provided with the data processing module.

As shown in fig. 3 to 5, for the schematic operation of the lidar lifting control system of the mobile robot according to the present invention, the mobile robot runs along direction F, and includes lidar 1, binocular camera 2 and obstacle 4, height mark H0 is a schematic diagram of the minimum height between obstacle 4 and the running ground, and under different conditions, such as obstacles with different shapes, sizes and heights, the minimum height between the connection line of the lowest point or points and the running ground is considered. When the laser radar 1 of the mobile robot is in a working position (namely, the position shown in the figure), the laser radar 1 comprises at least one transmitting end and at least one receiving end, and the mounting positions of the transmitting end and the receiving end are as close to the top position as possible, so that when the laser radar 1 receives the distance information of the obstacle, the signal that the obstacle can pass through only by reducing the height of the radar is represented to the greatest extent. The binocular camera 2 can obtain the size, shape and height of the barrier 4 and the distance from the mobile robot according to the existing positioning method, and in order to further understand the working principle of the binocular camera 2, the implementation process of the positioning method of the binocular camera 2 is specifically described: the binocular camera 2 respectively and independently obtains two image information of the same barrier at different angles at the same time for stereo matching, an image processing system can carry out data processing on the two images, the specific process is that binarization processing, Gaussian blur and canny operator contour detection are carried out on an original image, the contour of the barrier is searched, the barrier is completely framed out by a minimum quadrangle, the pixel size of the barrier is obtained by calculating four vertex coordinates of the quadrangle, the width and the height of the barrier can be calculated according to the triangle principle, and the size measurement of an allowed space is realized; the pixel coordinates of the center point of the object are obtained by calculating the coordinates of the four vertexes of the quadrangle, and the distance between the center point of the obstacle and the camera is obtained by a distance measurement principle. In order to further understand the working principle of the laser radar 1, the implementation process of the distance measuring method of the laser radar 1 is specifically described. Adopting TOF principle (abbreviation of Time of Flight), namely that the laser radar 1 emits modulated near infrared light, and reflects the light after encountering an object, and the sensor converts the distance of a target scenery by calculating the Time difference or phase difference between light emission and reflection so as to generate depth information; there are generally two methods of obtaining range information, the impulse method and the continuous wave method. The controller respectively acquires signals of the laser radar 1 and the binocular camera 2 in sequence, and the specific implementation process is that first information M1 such as distance and direction acquired by the laser radar 1 is collected and fed back to the controller, whether an obstacle 4 exists or not and the distance between the obstacle 4 are judged, and if the total height of the mobile robot after the laser radar 1 is lifted up is larger than the minimum height H0, the controller controls the laser radar 1 to do descending motion; second information M2 such as the shape, the height and the distance obtained by the binocular camera 2 is obtained and fed back to the controller, the controller obtains third information M3 containing the relative distance, the direction and the height value of an obstacle with accuracy, high precision and high reliability, the third information is further fed back to the laser radar 1, and if the height of the robot body 3 is smaller than the minimum height H0, the robot body smoothly passes through the obstacle. This has the advantage that, for example, the second information M2 of the binocular camera 2 is usually a stereo image source, and the viewing angle is shown as β, which results in that the binocular camera 2 can collect a short-distance and wide-range obstacle, but since the time consumed for the laser radar 1 to descend in the time operation process is usually more than 5 seconds, and the robot operation speed is usually 0.5M/s, it is usually necessary to judge the descending time in advance (before the mobile robot operates to the obstacle) in order to improve the efficiency, and therefore an obstacle collecting device with a longer distance is needed to realize the operation; the laser radar 1 (two-dimensional linear laser radar) can detect the obstacle signal with the same height as the radar within the range of about 10m, which greatly enhances the grasp of the descending time of the laser radar 1, but is limited by the information acquisition on the same horizontal plane and has low precision, so that only the direction and the approximate obstacle distance can be determined; it can be known that the fusion use of the binocular camera 2 and the laser radar 1 can be complemented and an unexpected technical effect can be obtained, namely, the laser radar 1 feeds back a signal to the controller for early warning in advance under the condition that the laser radar 1 accurately judges the relative direction and the long-distance first information M1 of the obstacle, when the mobile robot runs to the first position B1, the laser radar 1 descends, and the first position B1 is characterized in that the time required by the mobile robot to drive to the obstacle at a constant speed is just equal to the descending time of the laser radar 1, namely, the distance L1 of the mobile robot from the obstacle at the first position B1 is the time of multiplying the speed of the mobile robot by the time of the laser radar to retract into the body of the mobile robot; after the robot runs to the second position B2, the binocular camera 2 also acquires second information M2 of the obstacle and accurately knows the information of the minimum height, the shape, the distance and the like of the obstacle, the second position B2 is the position A of the obstacle which can be detected in the process that the binocular camera 2 is close to the position A of the obstacle, the controller obtains more complete information after processing and feeds the information back to the mobile robot to realize corresponding movement, namely, the mobile robot is controlled to execute avoidance actions such as halt, retreat or steering if the minimum height of the obstacle allowed to pass through is larger than the overall height of the robot body 3. According to the implementation process, the whole mobile robot does not need to be decelerated or stopped in the process of passing through the barrier space, and the descending time of the laser radar can be mastered in advance. To show the implementation more clearly, as shown in fig. 4 and 5, the first position B1 is at a distance L1 from the obstacle position a, and the maximum detection distance of the lidar 1 is greater than L1, so that the mobile robot is able to achieve descent of the lidar 1 without slowing down or stopping the mobile robot when it is between the first position B1 and the maximum effective detection position; the distance from the second position B2 to the obstacle position a is L3, and it is also possible to implement a brake stop if it is determined that the obstacle cannot pass within the distance of L3.

As shown in fig. 6 and 7, a specific embodiment of example 1 is shown. The mobile robot runs along the direction F, firstly, the laser radar 1 acquires information of an obstacle 41, when the detected obstacle information is coincident with a running path, the controller sends third information M3 to reduce the height of the laser radar 1, and at the moment, the mobile robot does not perform deceleration movement; when the robot continuously moves forwards towards the obstacle 41, the robot enters the effective detection range of the binocular camera 2 to obtain second information M2, wherein the second information M2 comprises the distance from the obstacle 41 and the minimum height H1 of the obstacle 41 from the ground, if the height (distance) L2 of the robot body 3 is smaller than the minimum height H1 of the obstacle 41 allowing the robot to pass through, the robot continuously moves forwards towards the obstacle 41 and passes through, otherwise, the controller controls to execute avoidance actions such as stopping or turning movement, the turning movement is movement towards other directions, and the radar is controlled to ascend to continuously move forwards as required after the robot is far away from the obstacle. The height of the robot body 3 is a distance L2 from the ground to the top of the robot body 3 after the laser radar 1 is retracted into the robot body 3.

After the laser radar 1 retracts into the robot body 3, the first signal M1 stops being acquired, and at the moment, the second signal M2 still keeps collecting and feeding back to the controller, so that the function of judging whether the whole robot completely passes through the obstacle in real time is realized. In the process, the mobile robot can record the running distance to ensure that the laser radar 1 can rise to the working position after smoothly passing through the obstacle after the second signal M2 is sent out, specifically, when the binocular camera 2 cannot detect the obstacle, the second signal M2 is sent out and fed back to the controller, when the controller sends out a rising instruction of the laser radar 1 after operation, the mobile robot further at least forwards runs the distance D to ensure that the laser radar 1 completely runs out of the obstacle 4 and then rises the laser radar 1 and continues to move forwards, the distance D is the distance from the front end of the mobile robot to the tail end (shown in figures 6 and 7) of the laser radar 1, and the tail end is the position where the laser radar 1 is far away from the maximum distance of the front end of the mobile robot. The precondition of this kind of scheme is that, after laser radar 1 contracts to mobile robot body 3 in, binocular camera 2 detects the total height that mobile robot when the space height that can pass is greater than laser radar 1 and rises, and laser radar 1 rises to normal operating condition can not take place in barrier collision scheduling problem this moment.

Example 2

As shown in fig. 8, this embodiment is a specific embodiment of embodiment 2, and the difference between this embodiment and embodiment 1 is that the laser radar 1 does not need to be lowered, and the other processes are the same as those of embodiment 1. When the minimum height H2 of the obstacle 42 from the running ground is larger than the total height of the mobile robot when the laser radar rises, the first information M1 cannot detect the obstacle, and the second information M2 detects that the height allows the mobile robot to pass through, so that the first information M1 and the second information M2 generate information fed back to the controller, the controller also passes through, and the controller sends a normal running instruction through the third information M3, so that the mobile robot smoothly passes through the obstacle 42 and continues to travel forwards.

The embodiments of the present invention disclosed herein are merely exemplary for the purpose of clearly illustrating the invention, and should not be considered as limiting the scope of the invention, and certainly not limiting the scope of the invention as claimed herein, it will be apparent to those skilled in the art that equivalent changes, modifications, variations, etc. made in the claims herein are intended to be included within the scope of the invention as defined in the appended claims.

Claims (8)

1. A method for controlling a mobile robot, comprising:

detecting the distance from an obstacle on the forward route to the mobile robot through the laser radar, and if the distance is less than the distance L1, controlling the laser radar to retract into the body of the mobile robot;

detecting the minimum height of the ground and the obstacle on the advancing route through a binocular camera, if the minimum height is greater than a distance L2, controlling the mobile robot to run through the obstacle along the current direction, and otherwise, controlling to execute an avoidance action;

the distance L1 is the speed of the mobile robot multiplied by the time of the laser radar shrinking into the mobile robot body, and the distance L2 is the height of the mobile robot after the laser radar shrinks into the mobile robot body.

2. The control method according to claim 1, characterized in that: the laser radar is a linear laser radar which can be rotatably installed on the mobile robot and comprises a transmitting end and a receiving end, wherein the transmitting end and the receiving end are close to the top end of the laser radar.

3. The control method according to claim 1, characterized in that: binocular camera fixed mounting is in mobile robot's direction of advance and two cameras are in same horizontal position.

4. The control method according to claim 3, characterized in that: the binocular camera comprises an image processing module used for processing the acquired image information.

5. The control method according to claim 3, characterized in that: the binocular camera system further comprises an image processing module which is independently arranged in the mobile robot or the server and is indirectly or directly connected with the binocular camera through a wireless communication system.

6. The control method according to claim 1, characterized in that: the avoidance operation includes turning, reversing, or stopping of the robot.

7. The control method according to claim 1, characterized in that: after laser radar contracts to the mobile robot body, when binocular camera detected that the space height that can pass through is greater than the total height of mobile robot when laser radar rose, the mobile robot was at least along the way distance D of moving when passing through the barrier, and distance D is the terminal linear distance of mobile robot front end to laser radar.

8. The utility model provides a mobile robot, includes robot body, liftable laser radar and binocular camera, its characterized in that:

the laser radar is used for detecting the distance from an obstacle to the mobile robot, and when the distance is less than L1, the laser radar is retracted into the mobile robot body;

the binocular camera is used for detecting the minimum height between the ground and the obstacle, and when the minimum height is less than the distance L2, the mobile robot is controlled to execute the avoidance action;

the distance L1 is the speed of the mobile robot multiplied by the time of the laser radar shrinking into the mobile robot body, and the distance L2 is the height of the mobile robot after the laser radar shrinks into the mobile robot body.

Images