Mobile robot and motion positioning control system thereof

Abstract

The utility model discloses a mobile robot and a motion positioning control system thereof, and relates to the technical field of engineering machinery. The system comprises: a mobile chassis; the sensing assembly is mounted on the movable chassis and at least comprises a linear structure light sensor; and the control device is electrically connected with the sensing assembly and is configured to carry out posture adjustment and displacement adjustment on the movable chassis according to the linear structured light emitted to the target workpiece by the linear structured light sensor in the deviation threshold range of the target point position. And the emitted line structured light is aligned with the target workpiece, and the mobile chassis reaches the target point position. According to the embodiment of the invention, the wire structured light sensor is configured, so that the control device can be combined with the wire structured light to perform posture adjustment and displacement adjustment of the mobile robot, fine positioning of the mobile robot is realized, and the mobile robot can adapt to more scenes.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of engineering machinery, in particular to a mobile robot and a motion positioning control system thereof. BACKGROUND

[0002] In the field of engineering machinery, a large number of industrial robots replace part of high-intensity and batch human work, but there are still problems to be solved. For example, in the welding operation, there are problems such as: 1) in the open and semi-open structure space, there are still a large number of discrete, full-position and small-size welds that need to be completed by manual welding; 2) the space moving range of the traditional industrial robot and the welding workstation is limited by the external track, so the space working range is limited, and the size, weight, cost and energy consumption are high.

[0003] To this end, the mobile robot is favored due to its lightness, flexibility, convenience, portability and other characteristics. For example, for the welding of discrete, full-position welds on large structures, the previous large, heavy and high-cost, high-energy consumption gantry special machine structure is replaced by a light, flexible, low-cost and low-energy consumption mobile welding robot, which greatly improves the working space range of the robot, saves the site space and reduces the cost investment.

[0004] At present, there are many ways to position the motion of the mobile robot, such as electromagnetic guidance navigation, which needs to lay electromagnetic tracks on the ground, which is troublesome to lay and difficult to change and expand the path. For example, two-dimensional code guidance, which obtains current position information by scanning the ground two-dimensional code through a camera, but a large number of two-dimensional codes need to be laid on site, and the two-dimensional codes are easy to wear and the maintenance cost is high. CONTENT OF THE UTILITY MODEL

[0005] The purpose of the embodiment of the present application is to provide a mobile robot and a motion positioning control system thereof, which at least partially solve the above technical problems.

[0006] In order to achieve the above purpose, the first aspect of the present application provides a motion positioning control system of a mobile robot, comprising: a mobile chassis; a sensing assembly mounted on the mobile chassis, the sensing assembly comprising at least a line structured light sensor; and a control device. The control device comprises: a transmission control module electrically connected to the line structured light sensor, configured to control the line structured light sensor to emit line structured light to a target workpiece within a deviation threshold range of a target point position; and a posture adjustment module configured to adjust the posture and displacement of the mobile chassis according to the line structured light continuously emitted by the line structured light sensor, so that the line structured light emitted by the line structured light sensor is aligned with the target workpiece and the mobile chassis reaches the target point position.

[0007] In the embodiment of the present application, the deviation threshold range is determined so that the target workpiece is within the field of view range corresponding to the line structured light when placed within the specified threshold range.

[0008] In the embodiment of the present application, the sensing assembly further includes a multi-line laser radar sensor mounted on the mobile chassis and configured to assist the mobile chassis to move to within the deviation threshold range of the target point position.

[0009] In the embodiment of the present application, the sensing assembly further includes an ultrasonic sensor mounted on the mobile chassis and configured to assist the mobile chassis to avoid obstacles.

[0010] In the embodiment of the present application, the motion positioning control system further includes a power assembly for providing power to the mobile chassis.

[0011] In the embodiment of the present application, the power assembly includes a power column for providing power and a rope winding mechanism arranged on the mobile robot and electrically connected to the mobile chassis, for connecting the power column through a power supply line to obtain power and provide the power to the mobile chassis.

[0012] In the embodiment of the present application, the control device is a controller integrated in the mobile chassis or a remote controller.

[0013] In the embodiment of the present application, the mobile chassis is a double-wheel chassis, a four-wheel chassis or a wheel-tracked composite chassis.

[0014] The second aspect of the present application provides a mobile robot including the motion positioning control system of the mobile robot as described above.

[0015] In the embodiment of the present application, the mobile robot is a mobile welding robot.

[0016] Through the above technical solution, the motion positioning control system of the mobile robot in the embodiment of the present application is configured with a line structured light sensor, so that the control device can adjust the posture and displacement of the mobile robot in combination with the line structured light, so as to make the mobile robot finally reach the target point position, and realize the precise positioning of the mobile robot. Without the need for additional setting of electromagnetic tracks, ground two-dimensional codes, vehicle-mounted vision sensors and various navigation devices, etc., the positioning accuracy is improved, and more scenes can be adapted.

[0017] Other features and advantages of the embodiments of the present application will be described in detail in the following specific implementation part. BRIEF DESCRIPTION OF DRAWINGS

[0018] The accompanying drawings are included to provide a further understanding of embodiments of the application, and are incorporated in and constitute a part of this specification, illustrate embodiments of the application, and together with the description serve to explain embodiments of the application, but do not limit the present application. In the drawings:

[0019] Figure 1 A structural block diagram of a motion positioning control system of a mobile robot according to an embodiment of the present application is schematically shown;

[0020] Figure 2 A flowchart of the motion positioning control performed by the motion positioning control system according to an embodiment of the present application is schematically shown;

[0021] Figure 3 A structural diagram of an example of a mobile welding robot system according to an embodiment of the present application is schematically shown;

[0022] Figure 4 A mobile welding robot coarse positioning diagram according to an example of an embodiment of the present application is schematically shown;

[0023] Figure 5 A main flowchart of the motion positioning control of the mobile welding robot according to an example of an embodiment of the present application is schematically shown;

[0024] Figure 6 A flowchart of the navigation motion fine positioning control strategy adopted by the mobile welding robot according to an example of an embodiment of the present application is schematically shown;

[0025] Figure 7 A diagram of the path tracking of the mobile welding robot according to an example of an embodiment of the present application is schematically shown;

[0026] Figure 8 A displacement tracking corner calculation principle diagram of the mobile welding robot according to an example of an embodiment of the present application is schematically shown;

[0027] Figure 9 A diagram of the point cloud straight line fitting according to an example of an embodiment of the present application is schematically shown;

[0028] Figure 10 A diagram of the mobile chassis posture adjustment according to an example of an embodiment of the present application is schematically shown;

[0029] Figure 11 A diagram of the robot lateral movement according to an example of an embodiment of the present application is schematically shown;

[0030] Figure 12(1)-Figure 12(4) A diagram of the robot movement control principle in a first scenario according to an example of an embodiment of the present application is schematically shown; and

[0031] Figure 13(1)-Figure 13(4) A schematic diagram illustrating a principle of robot movement control in a second scenario according to an example of embodiments of the present application is shown.

[0032] Legend of reference signs

[0033] 100 Sensing assembly 200 Control device

[0034] 1 Box steel structure 2 Structure light beam

[0035] 3 Weld seam tracking sensor 4 Welding robot and welding torch

[0036] 5 Multi-line laser radar sensor 6 Line structure light sensor

[0037] 7 Ultrasonic sensor 8 Mobile chassis

[0038] 9 Welding machine and welding system 10 Rope winding and hoisting mechanism

[0039] 11 Power supply line 12 Power supply column

[0040] 13 Threshold area range 14 Deviation threshold range DETAILED DESCRIPTION

[0041] To make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. It should be understood that the specific implementation manners described herein are only used to explain and illustrate the embodiments of the present application, and should not be used to limit the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the scope of protection of the present application.

[0042] It should be noted that the acquisition, transmission, storage, use, processing, and the like of data in the technical solutions of the present application comply with relevant provisions of laws and regulations. In the embodiments of the present application, some industry existing solutions, such as software, components, models, and the like, may be mentioned, which should be considered as exemplary, and the purpose is only to illustrate the feasibility in the implementation of the technical solutions of the present application, but does not mean that the applicant has or will necessarily use the solutions.

[0043] It should be noted that if the embodiments of the present application involve directional indications (such as up, down, left, right, front, back, and the like), the directional indications are only used to explain the relative positional relationship, movement condition, and the like between components in a certain posture (as shown in the drawings), and if the certain posture changes, the directional indications also change accordingly.

[0044] Furthermore, if the embodiments of this application involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, features defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions of various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. If the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed in this application.

[0045] Figure 1 This illustration schematically depicts a motion positioning control system for a mobile robot according to an embodiment of this application. The system includes: a mobile chassis ( Figure 1 (Not shown in the image); a sensing assembly 100 mounted on the mobile chassis, the sensing assembly 100 including at least a line structured light sensor; and a control device 200. The control device 200 includes: a transmission control module 210, electrically connected to the line structured light sensor, for controlling the line structured light sensor to emit line structured light toward the target workpiece within a deviation threshold range of the target point position; and an attitude adjustment module 220, for adjusting the attitude and displacement of the mobile chassis based on the continuously emitted line structured light from the line structured light sensor, so that the line structured light emitted by the line structured light sensor is aligned with the target workpiece and the mobile chassis reaches the target point position.

[0046] That is, in the embodiments of this application, for a mobile robot that is within the deviation threshold range of the target point position, the mobile chassis is continuously adjusted in attitude and displacement by the structured light continuously emitted by its line structured light sensor, so that the emitted line structured light is aligned with the target workpiece and the mobile chassis reaches the target point position, thereby completing the positioning of the mobile robot.

[0047] For example, a mobile chassis can be used to refer to a mobile robot. Figure 2 This illustration schematically depicts a flow chart illustrating the motion positioning control system of a mobile robot according to an embodiment of this application, demonstrating the execution of motion positioning control. Figure 2 As shown, the following steps S100-S200 may be included.

[0048] Step S100: When the mobile robot reaches the target point position within the deviation threshold range, the attitude of the mobile robot is adjusted according to the point cloud data obtained by the mobile robot emitting line structured light to the target workpiece, so that the emitted line structured light is aligned with the target workpiece.

[0049] The "controlling the mobile robot to reach within the deviation threshold range of the target point position" belongs to the coarse positioning of the mobile robot. Moreover, the emitted line structured light is aligned to the target workpiece, specifically, the optical axis of the line structured light is perpendicular to the irradiated outer surface of the target workpiece. Therefore, step S100 is to adjust the pose of the mobile robot based on the coarse positioning of the mobile robot, so that the line structured light emitted by the mobile robot can be perpendicularly irradiated to the outer surface of the target workpiece.

[0050] Step S200, after the pose adjustment, controlling the mobile robot to move linearly parallel to the target workpiece and continuously emit line structured light, and adjusting the lateral position of the mobile robot relative to the target workpiece according to the position change of the continuously emitted line structured light relative to the target workpiece, so that the mobile robot reaches the target point position.

[0051] That is, after step S100, the mobile robot has reached within the deviation threshold range of the target point position, and the emitted line structured light can be perpendicularly irradiated to the outer surface of the target workpiece, so that in this step S200, the mobile robot is controlled to move laterally according to the position change of the continuously emitted line structured light relative to the target workpiece, so that the mobile robot finally reaches the target point position, realizing the fine positioning of the mobile robot. In this process, the pose adjustment and fine positioning of the mobile robot by the line structured light do not require additional electromagnetic tracks, ground two-dimensional codes, vehicle-mounted vision sensors, various navigation devices, etc., which not only improves the positioning accuracy, but also can adapt to more scenes.

[0052] It should be noted that in the above steps, the mobile robot is controlled by the emission control module 210 to emit line structured light to the target workpiece, and the pose adjustment module 220 receives and analyzes the point cloud data corresponding to the line structured light to adaptively adjust the pose and displacement of the mobile robot, so that the line structured light emitted by the mobile robot can be perpendicularly irradiated to the outer surface of the target workpiece and the mobile robot can accurately reach the preset target point position. It should be noted that the emission control module 210 and the pose adjustment module 220 have the instruction control function, data receiving and analysis function, and robot action adjustment function of the conventional controller implemented herein. For example, the emission control module 210 can be a first processor for executing instruction control of the line structured light sensor, which is electrically connected to the line structured light sensor; and the pose adjustment module 220 can be a second processor for executing action control of the mobile chassis, which is electrically connected to the line structured light sensor and the action execution mechanism of the mobile chassis.

[0053] Figure 3The schematic diagram of the motion positioning control system of the mobile robot according to the preferred embodiment of the present application is shown, wherein the mobile robot is a mobile welding robot, and a mobile chassis 8 is marked in the diagram, which can be a four-wheel chassis as shown in the diagram, but is not limited thereto, and can also be a two-wheel chassis or a wheel-track composite chassis, etc.

[0054] In the preferred embodiment, in addition to the line structured light sensor 6, the sensing assembly 100 further comprises a multi-line laser radar sensor 5 mounted on the mobile chassis 8 and configured to assist the mobile chassis 8 to move to the target point position within the deviation threshold range.

[0055] In a more preferred embodiment, the sensing assembly 100 further comprises an ultrasonic sensor 7 mounted on the mobile chassis 8 and configured to assist the mobile chassis to avoid obstacles.

[0056] In addition, the motion positioning control system further comprises a power assembly for providing power to the mobile chassis. As Figure 3 shown, the power assembly comprises a power column 12 for providing power, and a rope winding hoisting mechanism 10 arranged on the mobile robot and electrically connected with the mobile chassis, for connecting the power column 12 through a power supply line 11 to obtain power and provide the power to the mobile chassis 8.

[0057] Further, the control device 200 is a controller integrated in the mobile chassis 8 or a remote controller, for example, a vehicle controller (VCU) of the mobile chassis 8.

[0058] Continuing as Figure 3 shown, the entire mobile welding robot system is composed of a large box steel structure 1, a structured light beam 2, a weld tracking sensor 3, a welding robot arm and a welding torch 4, a multi-line laser radar sensor 5, a large field of view line structured light sensor 6, an ultrasonic sensor 7, a mobile chassis 8, a welding machine and a welding system 9, a rope winding hoisting mechanism 10, a power supply line 11 and a power column 12, etc.

[0059] Among them, Figure 4 The schematic diagram of the coarse positioning of the mobile welding robot according to the example of the embodiment of the present application is shown. In combination with Figure 3 and Figure 4The large box steel structure 1 is placed randomly in the threshold area range 13, the coordinate system origin O of the multi-line laser radar sensor 5 is on the vertical line in the mobile chassis 8, the mobile chassis 8 models the large scene environment through the multi-line laser radar sensor 5 and specifies the target point position B. A path tracking PID navigation control algorithm can be developed for the multi-line laser radar sensor 5 to assist in controlling the mobile chassis 8 to navigate, avoid obstacles and coarsely position at any position (start point A) in the workshop. The ultrasonic sensor 7 is used to assist in controlling the mobile chassis 8 to avoid obstacles and reduce the blind area. When the mobile chassis 8 moves in the path planned by the multi-line laser radar sensor 5, the ultrasonic sensor 7 and the multi-line laser radar sensor 5 detect obstacles, which can assist in controlling the mobile chassis 8 to bypass the obstacles and move to the target point position B. The mobile chassis 8 and the power supply line 11 of the welding machine and the welding system 9 are connected to the power supply column 12 through the rope winding and winding mechanism 10. The rope winding and winding mechanism 10 matches the movement speed of the mobile chassis 8 to release and wind the power supply line 11. The rope winding and winding mechanism 10 can rotate 360° around its own base to follow the mobile chassis 8, and ensure that the angle of releasing and winding the power supply line 11 is always along the direction of the power supply line 11.

[0060] As shown in Figure 4 , the mobile chassis 8 navigates from the start point A to the target point B. Due to the deviation threshold range 14 and the deviation of the placement position of the large box steel structure 1, and due to the fixed movement trajectory of the welding robot and the welding torch 4, the welding position of the welding robot and the welding torch 4 is unreachable, and the pose of the mobile chassis 8 needs to be corrected twice, that is, the posture adjustment of step S100 and the fine positioning of step S200 are performed.

[0061] In the preferred embodiment of the present application, the deviation threshold range is determined such that the target workpiece is placed within the specified threshold area range within the field of view range corresponding to the line structured light. That is, corresponding to Figure 4 , the deviation threshold range 14 is determined such that the large box steel structure 1 is placed within the threshold area range 13 within the field of view range corresponding to the line structured light sensor 6. In this way, the problem of low navigation positioning accuracy of the mobile chassis 8 can be solved, and the arbitrary placement of the large box steel structure 1 within the threshold area range 13 can be realized.

[0062] Further, for Figure 3 and Figure 4 , a mobile welding robot navigation motion secondary fine positioning control strategy can be developed based on the motion positioning control system of the embodiments of the present application to improve the navigation positioning accuracy of the mobile chassis 8. It should be noted that when developing this secondary fine positioning control strategy, the preferred embodiment scheme of the present application is involved, and these schemes should also belong to the protection scope of the embodiments of the present application.

[0063] Specifically, Figure 5 a schematic diagram of a main flow of an example mobile welding robot motion positioning control according to an embodiment of the present application is shown, Figure 6 a flow chart of a navigation motion fine positioning control strategy adopted by an example mobile welding robot according to an embodiment of the present application is shown. As Figure 5 shown, it can include the following eight steps S1-S8, and each step is adaptively combined with Figure 6 the steps of the navigation motion fine positioning control strategy.

[0064] The first step S1 is to develop a set of mobile welding robot path tracking control algorithm to perform path navigation.

[0065] For example, Figure 7 a schematic diagram of an example mobile welding robot path tracking according to an embodiment of the present application is shown, which is based on Figure 3 and Figure 4 the example, the mobile welding robot is a four-wheel vehicle, so it is also referred to as a vehicle hereinafter. As Figure 7 shown, O G XY is the world coordinate system; O R XY is the travel coordinate system of the mobile chassis 8, which takes the geometric center of the vehicle as the origin; (Xg, Yg) is the point closest to the geometric center of the vehicle on the planned path, r represents the closest distance; θ is the deviation angle of the current vehicle course and the direction of the point on the road.

[0066] In the preferred embodiment of the present application, the path tracking scheme adopted includes: determining the turning angle of the virtual wheel according to the deviation factor between the actual path and the planned path of the mobile robot, wherein the virtual wheel is located at the intermediate position of a pair of actual walking wheels of the mobile robot; solving the turning angle of the actual walking wheel of the mobile robot according to the determined turning angle of the virtual wheel; and performing path tracking according to the turning angle of the actual walking wheel to control the mobile robot to reach the deviation threshold range of the target point position.

[0067] For this path tracking scheme, for example, Figure 7 a virtual tire is proposed, which is located at the intermediate position of the tire M1 and the tire M4, δ represents the turning angle of the virtual tire, and after the multi-line laser radar sensor 5 performs large scene environment modeling, the optimal path is planned at the starting point A and navigated to the target point position B. As Figure 7 shown, the multi-line laser radar sensor 5 obtains r and θ in the actual path and the planned path, when r and θ are both 0, the turning angles of the tires M1 and M4 are adjusted by the deviation of r and θ, wherein the deviation e(t) = r + θ. According to the classic PID, the turning angle δ of the virtual tire can be obtained as follows:

[0068]

[0069] Further, Figure 8 A schematic diagram of a mobile welding robot displacement tracking corner calculation example according to an embodiment of the present application is shown. The virtual tire corner δ obtained according to equation (1) can be used to obtain the real-time corner δ1 of the actual tire M1 and the real-time corner δ2 of the actual tire M4 synchronously, as shown, so as to realize high-precision navigation tracking. The corresponding corner calculation formula is as follows: Figure 8

[0070]

[0071] Where D and d are the wheelbase between the front and rear wheels and the left and right wheels, respectively, and equations (2) and (3) show the conventional Ackerman chassis tire corner solving method.

[0072] The accuracy of the mobile chassis 8 in navigating and positioning to the target point position B is tested by experiment, and the deviation threshold range 14 of the navigation and positioning can be determined accordingly. Then, according to the deviation threshold range 14 and the field range of the large field line structured light sensor 6, the threshold area range 13 of the large box steel structure 1 is determined to ensure that the mobile chassis 8 navigates to the deviation threshold range 14 of the target point position B. In this way, the large box steel structure 1 is placed anywhere within the threshold area range 13, and is within the field range of the large field line structured light sensor 6.

[0073] In the second step S2, a single line structured light is emitted to scan the surface of the target workpiece.

[0074] As shown in Figure 4 Within the deviation threshold range of the target point position B, the large field line structured light sensor 6 is triggered once to obtain the effective point cloud data of the light irradiation of the outer surface of the large box steel structure 1 within the field range.

[0075] After the second step, the preferred embodiment of the present application adjusts the posture of the mobile robot by the following steps: performing straight line fitting on the point cloud data, and selecting a first straight line from the fitted straight lines; translating the first straight line along the Z-axis of the line structured light plane coordinate system to obtain a second straight line intersecting the X-axis of the line structured light plane coordinate system, wherein the optical axis corresponding to the line structured light is the Z-axis, and the axis perpendicular to the Z-axis is the X-axis; obtaining the included angle between the second straight line and the X-axis of the line structured light plane coordinate system as the body rotation angle; and controlling the mobile robot to rotate the body around the body axis by the body rotation angle to complete the posture adjustment. Wherein, as shown in Figure 9 10 ​​As shown, the line structured light plane coordinate system is an XOZ coordinate system, with the line structured light emission point O as the origin, the optical axis of the line structured light as the Z-axis, and the X-axis perpendicular to the Z-axis. It is easy to see that the X-axis corresponds to the edge line of the mobile robot. In its initial posture, the line structured light emitted by the mobile robot cannot be aligned with the target workpiece. However, after rotating the robot around its axis by the specified rotation angle, the X-axis of the robot's edge line becomes parallel to the target workpiece, allowing the emitted line structured light to be aligned with it.

[0076] When this posture adjustment scheme is applied to the above example, it may specifically include the following steps: S3, S4, and S5.

[0077] The third step, S3, involves processing the point cloud data.

[0078] The point cloud data undergoes secondary processing. For example, first, the density clustering algorithm DBSCN is used to classify the point clouds, and then a least-squares method is used to fit a straight line to the point clouds of each class. Figure 9 The illustration shows a schematic diagram of point cloud linear fitting according to an example embodiment of this application. For example... Figure 9 As shown, the point cloud set with the largest number of points, fg, is selected. c Z c ),(X c+1 Z c+1 ),……(X d Z d Furthermore, the slope k of the straight line can also be calculated. The straight line fg is the first straight line in the preferred embodiment of this application.

[0079] Step S4: Calculate the vehicle body rotation angle.

[0080] Figure 10 This diagram schematically illustrates an example of mobile chassis attitude adjustment according to an embodiment of this application. Figure 9 As shown, a straight line fg was obtained in the coordinate system O of the large box-shaped steel structure component 1 by triggering a single scan using structured light and processing the point cloud. The straight line fg was then translated along the Z-axis to intersect the X-axis at point f', thus obtaining the straight line f. ′ g ′ The straight line f ′ g ′ This is the second straight line in the preferred embodiment of this application. Based on the slope k, we obtain... Figure 9 The straight line f in ′ The angle between g′ and the X-axis of the large field-of-view structured light sensor 6 is:

[0081] θ = tan -1 k (4)

[0082] Step 5, S5: Adjust vehicle posture.

[0083] Figure 9 The straight line f in ′ The angle θ between g′ and the X-axis of the large field-of-view structured light sensor 6 is the angle by which the moving chassis 8 needs to rotate in place around the vehicle body axis. If θ > 0, the moving chassis 8 rotates clockwise around the vehicle body axis by θ°. If θ < 0, the moving chassis 8 rotates counterclockwise around the vehicle body axis by θ°, thus adjusting the attitude of the moving chassis 8 and obtaining position C. Figure 10 As shown, after rotating θ°, the straight line f obtained in the new attitude is... ′ g′ is parallel to the edge line of the mobile robot and the target workpiece.

[0084] After the posture adjustment is completed in the fifth step, the preferred embodiment of this application adjusts the lateral position of the mobile robot relative to the target workpiece through the following steps to achieve precise positioning: determining the transverse straight line intersecting the line structured light plane with the outer surface of the target workpiece; and controlling the mobile robot to move along the direction of the transverse straight line according to the current position of the mobile robot and the current position change of the line structured light relative to the transverse straight line, so that the mobile robot reaches the target point position.

[0085] When this precise positioning scheme is applied to the above example, it may specifically include the following steps: S6, S7, and S8.

[0086] Step S6: Determine the transverse straight line that intersects the line structured light plane with the outer surface of the target workpiece.

[0087] After adjusting the body posture of the mobile chassis 8, the large field-of-view structured light sensor 6 is continuously triggered to scan the outer surface of the large box-shaped steel structure component 1. Figure 11 The diagram illustrates an example of lateral movement of a robot according to an embodiment of this application. The large field-of-view line structured light sensor 6 is defined with respect to the origin O coordinate system and the plane formed by the X and Z axes, i.e., the line structured light plane coordinate system mentioned above. Through this coordinate system, the transverse straight line intersecting the outer surface of the large box-shaped steel structure 1 is denoted as ab, and the midpoint of ab is e.

[0088] Step 7, S7: Precise positioning and implementation.

[0089] After the sixth step of determining the cross straight line intersected by the plane of the line structured light and the outer surface of the target workpiece, the current position of the mobile robot and the position change of the current line structured light relative to the cross straight line are further determined to control the mobile robot to move along the direction of the cross straight line. In a preferred embodiment of the present application, the control of the mobile robot to move along the direction of the cross straight line can include the following first movement control step and second movement control step.

[0090] The first movement control step controls the mobile robot to move in a first direction until the corresponding line structured light covers the second end point of the cross straight line, and then controls the mobile robot to stop, in the case that the line structured light emitted by the mobile robot at the current position after the posture adjustment covers the first end point of the cross straight line and cannot cover the second end point of the cross straight line, wherein the first direction is the direction in which the first end point points to the second end point, and the second direction is opposite to the first direction.

[0091] The second movement control step controls the mobile robot to move in the second direction until the optical axis point of the corresponding line structured light coincides with the midpoint of the cross straight line, and then controls the mobile robot to stop, in the case that the line structured light emitted by the mobile robot at the current position after the posture adjustment cannot cover any end point of the cross straight line and cannot generate point cloud data, wherein the position of the mobile robot when the coincidence occurs is the target point position.

[0092] Further, in another preferred embodiment, the third movement control step and the fourth movement control step can also be included.

[0093] The third movement control step controls the mobile robot to move in the first direction until the corresponding line structured light covers the first end point, and then starts to execute the first movement control step, in the case that the line structured light emitted by the mobile robot at the current position after the posture adjustment cannot cover any end point of the cross straight line and cannot generate point cloud data.

[0094] The fourth movement control step controls the mobile robot to move in the second direction until the corresponding line structured light covers the first end point, and then starts to execute the first movement control step, in the case that the line structured light emitted by the mobile robot at the current position after the posture adjustment cannot cover any end point of the cross straight line and can generate point cloud data.

[0095] In addition, during the execution of any of the above movement control steps, the length of the cross straight line can be determined as the width of the target workpiece according to the moving distance of the mobile robot along the direction of the cross straight line and the distance of the end points of the cross straight line relative to the optical axis point of the current line structured light on the cross straight line, and the model of the target workpiece can be determined according to the width of the target workpiece.

[0096] Now back to the example of the seventh step, the control scenarios corresponding to the above four moving control steps are described in detail. In the seventh step, according to the fifth step, the chassis 8 adjusts the attitude of the vehicle body and obtains the position C. At this time, the large field of view line structured light sensor 6 is continuously triggered, and the continuously emitted current line structured light (light ray cd) will appear the following situations:

[0097] (1) Corresponding to the first moving control step, as shown in FIG. 12(1), if the position C of the chassis 8 is on the ae side, the point c is on the left side of the point a, and a is on the left side of the origin O, the large field of view line structured light sensor 6 is closed, and the chassis 8 is in a static state. Trigger the large field of view line structured light sensor 6 once, and record the distance of the point a on the line segment ao in the large field of view line structured light sensor 6. Continuously trigger the large field of view line structured light sensor 6, and control the chassis 8 to move linearly along the direction. When the point d in the light ray cd emitted by the large field of view line structured light sensor 6 is on the right side of the point b, and the point b is on the right side of the origin O, stop the chassis 8 at the position D. The wheel hub motor encoder of the chassis 8 records the moving distance CD. Close the large field of view line structured light sensor 6, and the chassis 8 is in a static state. Trigger the large field of view line structured light sensor 6 once, and record the distance of the point b on the line segment ob in the large field of view line structured light sensor 6. As shown in FIG. 12(1), the width size ab = ao+CD+ob of the large box steel structure 1 can be obtained. According to the width size, the model of the large box steel structure 1 can be confirmed. Finally, control the chassis 8 to move linearly from the position D to the position E along the direction, and the position E is at the midpoint of the line segment ab,

[0098] It is known that, corresponding to the first moving control step, the points a and b are the first end point and the second end point of the cross straight line respectively, and the first direction is the direction, and the second direction is the direction. It should be noted that, Figure 12(1)-Figure 12(4) the end points and the moving direction are defined similarly, and will not be repeated in the following description.

[0099] (2) Corresponding to the second moving control step, if the position C of the chassis 8 is on the ae side, the point c is on the left side of the point a, and the point a is on the right side of the origin O, and the point d is on the right side of the origin a. As shown in FIG. 12(2), according to the steps in the seventh step (1), the width size ab = CD-oa+ob of the large box steel structure 1 can be obtained. According to the width size, the model of the large box steel structure 1 can be confirmed. Finally, control the chassis 8 to move linearly from the position D to the position E along the direction, and the position E is at the midpoint of the line segment ab, DE = ab / 2-ob.

[0100] (3) Corresponding to the second moving control step, if the position C of the moving base 8 is at the ae side, the point d is at the left side of the point a. As shown in Fig. 12(3), the large field of view line structured light sensor 6 is continuously triggered, and the moving base 8 is controlled to move linearly along the direction of When the point d in the light ray cd emitted by the large field of view line structured light sensor 6 is at the right side of the point a, the moving base 8 is stopped, and the state is consistent with Fig. 12(2). According to the step in the seventh step (2), the width size ab of the large box steel structure 1 can be obtained by the same principle, ab = CD - oa + ob. According to the width size, the model of the large box steel structure 1 can be confirmed. Finally, the moving base 8 is controlled to move linearly from the position D to the position E along the direction of The position E is at the midpoint of the line segment ab, DE = ab / 2 - ob.

[0101] (4) Corresponding to the fourth moving control step, if the position C of the moving base 8 is at the ae side, the point c is at the right side of the point a. As shown in Fig. 12(4), the large field of view line structured light sensor 6 is continuously triggered, and the moving base 8 is controlled to move linearly along the direction of When the point c in the light ray cd emitted by the large field of view line structured light sensor 6 is at the left side of the point a, the moving base 8 is stopped. The state is consistent with Fig. 12(1), and according to the step in the seventh step (1), the width size ab of the large box steel structure 1 can be obtained by the same principle, ab = ao + CD + ob. According to the width size, the model of the large box steel structure 1 can be confirmed. Finally, the moving base 8 is controlled to move linearly from the position D to the position E along the direction of The position E is at the midpoint of the line segment ab, DE = ab / 2 - ob.

[0102] (5) The points c and a, the origin O and the point a, and the point d and the point a are exactly coincident. Since the sensor accuracy cannot achieve such ideal state, it is not considered.

[0103] (6) With respect to the endpoints and the moving direction of Figure 12(1)-Figure 12(4) Figure 13(1)-Figure 13(4) the opposite moving direction. That is, in Figure 13(1)-Figure 13(4) corresponding to the first moving control step, the points b and a are the first endpoint and the second endpoint of the cross straight line respectively, and the first direction is the direction, and the second direction is the direction.

[0104] ​Thus, corresponding to the first moving control step, as shown in Fig. 13(1), if the position C of the moving chassis 8 is at the be side, the point d is at the right side of the point b, and the point b is at the right side of the original point O, the large field of view line structured light sensor 6 is closed, and the moving chassis 8 is in a static state. The large field of view line structured light sensor 6 is triggered once, and the distance of the point b from the line segment bo in the large field of view line structured light sensor 6 is recorded. The large field of view line structured light sensor 6 is continuously triggered, and the moving chassis 8 is controlled to move linearly along the direction of When the point c in the light ray cd emitted by the large field of view line structured light sensor 6 is at the left side of the point a, and the point a is at the left side of the original point O, the moving chassis 8 is stopped, and is at the position D. The wheel hub motor encoder of the moving chassis 8 records the moving distance CD. The large field of view line structured light sensor 6 is closed, and the moving chassis 8 is in a static state. The large field of view line structured light sensor 6 is triggered once, and the distance of the point a from the line segment oa in the large field of view line structured light sensor 6 is recorded. As shown in Fig. 13(1), the width size ab = oa + CD + ob of the large box steel structure 1 can be obtained, and the type of the large box steel structure 1 can be confirmed according to the width size. Finally, the moving chassis 8 is controlled to move linearly along the direction of from the position D to the position E, and the position E is at the midpoint of the line segment ab, DE = ab / 2 - oa.

[0105] (7) Corresponding to the second moving control step, as shown in Fig. 13(2), if the position C of the moving chassis 8 is at the be side, the point d is at the right side of the point b, and the point b is at the left side of the original point O, and the point c is at the left side of the point b. According to the step in the seventh step (6), the width size ab = CD + oa - ob of the large box steel structure 1 can be obtained, and the type of the large box steel structure 1 can be confirmed according to the width size. Finally, the moving chassis 8 is controlled to move linearly along the direction of from the position D to the position E, and the position E is at the midpoint of the line segment ab, DE = ab / 2 - oa.

[0106] (8) Corresponding to the third moving control step, as shown in Fig. 13(3), if the position C of the moving chassis 8 is at the be side, the point c is at the right side of the point b, the large field of view line structured light sensor 6 is continuously triggered, and the moving chassis 8 is controlled to move linearly along the direction of When the point c in the light ray cd emitted by the large field of view line structured light sensor 6 is at the left side of the point b, the moving chassis 8 is stopped, and the state is consistent with that shown in Fig. 13(2). According to the step in the seventh step (7), the width size ab = CD + oa - ob of the large box steel structure 1 can be obtained, and the type of the large box steel structure 1 can be confirmed according to the width size. Finally, the moving chassis 8 is controlled to move linearly along the direction of from the position D to the position E, and the position E is at the midpoint of the line segment ab, DE = ab / 2 - oa.

[0107] (9) Corresponding to the fourth movement control step, as shown in Figure 13(4), if the position C of the moving chassis 8 is on the be side, and point d is to the left of point b. As shown in Figure 13(4), the large field-of-view structured light sensor 6 is continuously triggered, and the moving chassis 8 is controlled to move along the line. The direction is to move in a straight line. When point d in the light ray cd emitted by the large field-of-view structured light sensor 6 is to the right of point b, the moving chassis 8 stops. At this time, the state is consistent with that in Figure 13(1). According to the steps in step 7 (6), the width dimension ab = oa + CD + ob of the large box steel structure component 1 can be obtained. According to the width dimension, the model of the large box steel structure component 1 can be confirmed. Finally, control the moving chassis (8) to move along the direction of the structured light sensor 6. The direction is a straight line from position D to position E, and position E is the midpoint of line segment ab. DE = ab / 2 - oa.

[0108] (10) The case where point c and point b, origin O and point b, and point d and point b just coincide is not considered because the sensor accuracy cannot achieve such an ideal state.

[0109] Step 8, S8: Control the mobile robot to work.

[0110] Based on steps five and seven, Figure 12(1)-Figure 13(4) As shown, the current orientation of the mobile chassis 8 is such that its perpendicular bisector is perpendicular to the plane containing the straight line ab of the large box-shaped steel structure 1, and the position of the perpendicular bisector of the mobile chassis 8 is at the midpoint e of the straight line ab. At this point, the expected target point B has been reached. The large field-of-view structured light sensor 6 is triggered once to confirm the distance between the mobile chassis 8 and the large box-shaped steel structure 1, and the mobile chassis 8 is adjusted to move forward or backward to the preset position to begin work.

[0111] Therefore, the example of this application embodiment completes the pose adjustment of the mobile chassis 8 in eight steps, and realizes the model identification of the large box-shaped steel structure component 1 and the secondary precise positioning of the vehicle body, solving the problem of welding work that cannot be carried out according to the preset robot trajectory due to poor navigation accuracy, inaccurate positioning, and workpiece placement position deviation. Specifically, the example of this application embodiment includes at least the following innovative technical solutions:

[0112] 1. A proposal is made to create a virtual tire and simultaneously solve the actual tire turning angle through the virtual tire, thereby realizing PID closed-loop control for path tracking of mobile robots.

[0113] 2. Point cloud data is acquired by scanning the workpiece surface with line structured light. Interference point clouds are filtered using methods such as density clustering, and straight lines are fitted using the least squares method to obtain straight line point clouds. Then, the angle θ between the vehicle body and the horizontal plane of the workpiece is calculated, and the vehicle body is controlled to rotate around the predetermined angle θ to achieve attitude adjustment.

[0114] 3. The workpiece surface is continuously scanned by the line structured light, and the mobile robot is controlled to move linearly along the horizontal direction of the workpiece surface. The end position of the mobile robot in the horizontal direction of the workpiece is determined by the mutation of the point cloud data. Then, the coordinates in the sensor are obtained by the robot static shooting of the point cloud at both ends of the workpiece in the horizontal direction, and the encoder distance of the mobile robot is calculated. In this way, the distance size of the workpiece horizontal plane at both ends can be calculated, and the robot is controlled to move to the threshold range of the workpiece horizontal X axis. The point cloud data mutation can be understood with reference to the above, mainly referring to the process from nothing to something or from something to nothing, for example, in the field of view range of the line structured light, the point cloud is generated on the workpiece, or the point cloud disappears, showing the phenomenon of point cloud mutation.

[0115] 4. The workpiece is scanned by the line structured light, the distance of the workpiece from the Z axis direction of the mobile robot is determined, and the position of the mobile robot in the Z axis direction is controlled.

[0116] Therefore, in the application scene of the mobile welding robot system in this example, the embodiment scheme of the present application can solve the problems of low navigation accuracy, inability to converge to the target position, etc.; can realize large box steel structure type identification and body pose adjustment and then secondary precise positioning, solve the problem that the workpiece placement position offset cannot be welded according to the preset robot trajectory; can also solve the problems of the traditional workpiece identification and positioning scheme, such as large cost investment, large amount of point cloud data, complex algorithm, low stability, low registration success rate, etc.

[0117] It should be noted that in addition to the four-wheel mobile welding robot shown in the above example, the embodiment scheme of the present application can also be applied to two-wheel mobile robots, and can also be applied to mobile robots performing other work (such as wall painting, brick laying, and carrying).

[0118] In addition, the line structured light sensor in the above example is not limited to the type of line structured light, and other sensors that can obtain the point cloud coordinates (x, z) values of straight lines or planes can be substituted, and all should belong to the protection scope of the embodiment of the present application.

[0119] In summary, through the above example, the motion positioning control system of the mobile robot of the embodiment of the present application essentially provides a scheme of "target point position coarse positioning + robot pose adjustment + target point position precise positioning", which can be specifically described as:

[0120] First, a virtual tire of the mobile chassis is created, a three-dimensional visual sensor such as a laser radar sensor is used for environment scanning, an Ackerman chassis tire steering angle is planned and solved synchronously, and a target point position coarse positioning is realized through mobile robot path tracking PID closed loop control.

[0121] Second, the workpiece surface is scanned by using the line structure light at the position of the coarse positioning, noise is filtered by using a point cloud algorithm, and a straight line vector of the point cloud on the workpiece surface is obtained by fitting a straight line through a least square method, so that an included angle θ between a coordinate axis X axis vector of the line structure light and the straight line vector, i.e., a body posture angle, is solved, and the body posture adjustment is realized.

[0122] Third, after the body posture adjustment is completed, the workpiece surface is continuously scanned by using the line structure light, and a transverse straight line motion of the moving chassis is controlled along a horizontal direction of the workpiece surface, and whether the moving chassis reaches an end position of the workpiece is determined through a point cloud data mutation, and the moving chassis is stopped at the end position. The point clouds at two ends of the workpiece in the horizontal direction are scanned statically, coordinate points of the two ends of the workpiece in the sensor are obtained, and distances walked by the moving chassis when moving to the two ends are recorded synchronously, the distance between the two ends of the workpiece is calculated comprehensively, and the workpiece model is matched with a process library. In addition, a relative position relationship between the moving chassis and the workpiece in the X axis and Z axis coordinate systems is solved, the robot is controlled to move to a preset target position, and the secondary precise positioning of the moving chassis is realized.

[0123] Further, based on the scheme of "target position coarse positioning + robot posture adjustment + target position precise positioning", the embodiments of the present application have at least the following advantages:

[0124] First, the embodiments of the present application propose a scheme of realizing the navigation path PID closed-loop control based on the virtual tire path tracking control strategy, and solve the problems of low traditional navigation accuracy and the inability of the target position to converge.

[0125] Second, the embodiments of the present application propose a scheme of identifying the large workpiece model based on the visual sensor, and a set of mobile robot motion secondary precise positioning control strategy can be developed correspondingly, which can realize the model identification of the target workpiece, and can perform the secondary precise positioning based on the body posture adjustment, and solve the problem that the robot cannot work according to the preset robot track due to the poor navigation accuracy, inaccurate positioning, and workpiece placement position deviation.

[0126] Third, compared with the traditional workpiece identification and positioning scheme, the embodiments of the present application do not need to model the large workpiece in advance, and do not need to use multiple cameras and multiple shooting positions to shoot the workpiece to screen, splice and model point cloud data of a large number of workpieces. Compared with the traditional workpiece identification and positioning scheme, the embodiments of the present application have the advantages of low cost, small point cloud data, simple algorithm, high stability and high registration success rate.

[0127] The embodiments of the present application also provide a mobile robot, which comprises the motion positioning control system of the mobile robot. Figure 3The mobile welding robot shown can also be a mobile robot that performs wall painting, tile laying, carrying, and the like.

[0128] Those skilled in the art will understand that embodiments of the present application can be provided as methods, systems or computer program products. Thus, the present application can take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present application can take the form of a computer program product on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROMs, optical storage devices, etc.) embodying computer readable program code.

[0129] The present application is described in reference to the flow diagrams and / or block diagrams of the methods, apparatus (systems), computer program products according to embodiments of the application. It will be understood that each block of the flow diagrams and / or block diagrams, and combinations of blocks in the flow diagrams and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general purpose computer, special purpose computer, embedded processing device or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flow diagrams and / or block diagrams block or blocks. Figure 1 one or more functions specified in the flow diagram and / or block diagram block or blocks. Figure 1 means for performing each of the functions specified in the flow diagram and / or block diagram block or blocks.

[0130] These computer program instructions can also be stored in a computer- readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instructions which implement the flow diagrams and / or block diagrams block or blocks. Figure 1 one or more functions specified in the flow diagram and / or block diagram block or blocks. Figure 1 means for performing each of the functions specified in the flow diagram and / or block diagram block or blocks.

[0131] These computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the flow diagrams and / or block diagrams block or blocks. Figure 1 one or more functions specified in the flow diagram and / or block diagram block or blocks. Figure 1 means for performing each of the functions specified in the flow diagram and / or block diagram block or blocks.

[0132] In one typical configuration, the computing device includes one or more processors (CPUs), input / output interfaces, network interfaces, and memory.

[0133] Memory can include non-persistent memory, Random Access Memory (RAM), and / or non-volatile memory, such as Read Only Memory (ROM) or flash memory, in a computer readable medium. Memory is an example of computer readable media.

[0134] Computer readable media includes permanent and non-permanent, removable and non-removable media implemented in any method or technology for storage of information such as computer readable instructions, data structures, program modules or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read only memory (ROM), electrically erasable programmable read only memory (EEPROM), flash memory or other memory technology, compact disc read only memory (CD-ROM), digital versatile discs (DVDs) or other optical storage, magnetic cassettes, magnetic disks storage or other magnetic storage devices, or any other non-transmission medium that can be used to store information accessible to a computing device. According to the definition herein, computer readable media does not include transitory media, such as modulated data signals and carrier waves.

[0135] It should also be noted that the terms "comprising", "containing", or any other variant thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article or apparatus that comprises a list of elements does not include only those elements in the list, but can also include other elements not expressly listed or inherent to such process, method, article or apparatus. Without further limitation, an element defined by the statement "comprising a" does not exclude the presence of additional identical elements in the process, method, article or apparatus that includes the element.

[0136] The above merely provides an example of the present application and is not intended to limit the present application. The present application can have various modifications and changes for those skilled in the art. Any modification, equivalent replacement, improvement, etc. within the spirit and principle of the present application shall be included in the scope of claims of the present application.

Claims

1. A motion positioning control system for a mobile robot, characterized by, The motion positioning control system comprises: a mobile chassis; a sensing assembly mounted on the mobile chassis, the sensing assembly comprising at least a line structured light sensor; and a control device comprising: a transmission control module electrically connected to the line structured light sensor, configured to control the line structured light sensor to emit line structured light to a target workpiece within a deviation threshold range of a target point position; and a posture adjustment module configured to perform posture adjustment and displacement adjustment on the mobile chassis according to the line structured light continuously emitted by the line structured light sensor, so that the line structured light emitted by the line structured light sensor is aligned with the target workpiece and the mobile chassis reaches the target point position.

2. The motion positioning control system of claim 1, wherein, The deviation threshold range is determined so that the target workpiece is within the field of view of the line structured light sensor when placed within a specified threshold area range.

3. The motion positioning control system of claim 1, wherein, The sensing assembly further comprises a multi-line laser radar sensor mounted on the mobile chassis, configured to assist the mobile chassis to travel within the deviation threshold range of the target point position.

4. The motion positioning control system of claim 1, wherein, The sensing assembly further comprises an ultrasonic sensor mounted on the mobile chassis, configured to assist the mobile chassis to avoid obstacles.

5. The motion positioning control system of claim 1, wherein, The motion positioning control system further comprises: a power assembly configured to provide power to the mobile chassis.

6. The motion positioning control system of claim 5, wherein, The power assembly comprises: a power column configured to provide power; and a rope winding and hoisting mechanism arranged on the mobile robot and electrically connected to the mobile chassis, configured to connect the power column through a power supply line to obtain power and provide the power to the mobile chassis.

7. The motion positioning control system of claim 1, wherein, The control device is a controller integrated in the mobile chassis or a remote controller.

8. The motion positioning control system of any one of claims 1 to 7, wherein, The mobile chassis is a double-wheel chassis, a four-wheel chassis or a wheel-tracked composite chassis.

9. A mobile robot, characterized by The motion positioning control system comprises any one of claims 1 to 8.

10. The mobile robot of claim 9, wherein, The mobile robot is a mobile welding robot.

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