Printing operation method of mobile robot

Abstract

The invention discloses a mobile robot printing operation method, which comprises the following steps of: 1, starting and initializing a mobile robot, automatically calibrating a zero position of a spraying printing head, and extracting data information of an operation map; 2, determining a laser positioning placing position, completing leveling of laser positioning equipment, and measuring and tracking the position of the robot through a target ball installed on the robot; 3, generating an automatic operation path: selecting a to-be-operated map, aligning a reference, mapping a map coordinate system to a ground operation area, editing the map to set obstacle information, selecting part or all of the operation range, setting parameters, calling a path planning algorithm to generate the operation path and printing process information; step 4, the robot performs printing operation in the operation area according to the operation path and the printing process information; finishing the automatic operation flow after the printing operation is finished; the absolute positioning device is used for measuring the reflection device installed at the mobile robot end, and the position precision of spraying, printing and positioning of the mobile robot is optimized.

Description

Technical Field

[0001] The invention belongs to the technical field of mobile printing, and in particular relates to a mobile robot printing operation method. Background Art

[0002] Mobile robots with spray printing functions can be used in a variety of scenarios, mainly in building construction site layout, factory planning and positioning layout, exhibition venue planning and layout, road sign and marking construction, etc. The technology of this application is a mobile robot that is used to spray or print symbols, text, curves and other marks with specified meanings on a flat surface (such as the ground for construction of building decoration, the ground for factory equipment installation, the ground for exhibition hall layout, the ground for road construction sign and marking, etc.).

[0003] The most difficult challenge for such mobile robots is how to accurately and accurately transmit design information on a plane. In actual engineering applications, the accuracy required by the construction party is generally at the centimeter or even millimeter level. However, it is difficult for mobile robots to position so accurately. The commonly used method for positioning a mobile robot in space is to use sensors (usually lidar) to perceive the distance between the robot and the known surrounding environment, i.e., the map (such as walls and columns) in real time. At present, the top sensors can only achieve centimeter-level accuracy positioning. Even when the mapping and positioning algorithms are repeatedly optimized, this limits the positioning ability of the mobile robot. At present, in the above-mentioned application scenarios, manual physical marking is usually used to present paper design drawings and digital requirements on the construction ground. In actual operation, engineers mainly use manual measurement and physical marking, such as measuring the distance between columns and walls, and pulling ink lines to lay out the lines on the work surface. In this process, a total station is usually used for precise guidance to improve work efficiency and positioning accuracy.

[0004] Absolute positioning devices are generally based on light and automatic control technology to achieve high-precision three-dimensional measurement. They are portable and are mainly used in the field of large-scale spatial coordinate measurement. Advanced technologies such as laser interference distance and angle measurement are usually used. Based on the measurement principle of the spherical coordinate method, accurate measurement of three-dimensional coordinates can be achieved by measuring angles and distances. At present, in the field of large-scale precision measurement, laser trackers with the advantages of wide measurement range, high precision, multiple functions, and on-site measurement are generally used. It can replace many traditional measuring equipment, such as large fixed three-dimensional coordinate measuring machines, theodolites and total stations, and show high measurement accuracy and efficiency in application fields such as equipment calibration, parts inspection, tooling manufacturing and debugging, integrated assembly and reverse engineering. In the field of precision engineering measurement or deformation monitoring such as general large-scale buildings, underground tunnel construction, and venue construction, total stations (total station electronic tachometers) with multiple functions such as angle measurement, distance (slant distance, horizontal distance, height difference) measurement, three-dimensional coordinate measurement, wire measurement, intersection point measurement, and layout measurement are widely used. Summary of the invention

[0005] The purpose of the present invention is to design a mobile robot printing operation method, wherein the mobile robot has the function of moving along any planned trajectory in a plane and can draw the contour of the moving trajectory.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0007] A mobile robot printing operation method, characterized in that: the method is as follows:

[0008] Step 1: Start and initialize the mobile robot, automatically calibrate the zero position of the spray print head, and extract data information of the operation map;

[0009] Step 2: Determine the laser positioning position, complete the leveling of the laser positioning equipment, and measure and track the position of the robot through the target ball installed on the robot;

[0010] Step 3: Generate automatic operation path: select the map to be operated, align the benchmark, map the map coordinate system to the ground operation area, edit the map to set obstacle information, select part or all of the operation range, set parameters, call the path planning algorithm to generate the operation path and print process information;

[0011] Step 4: The robot performs printing in the working area according to the working path and printing process information; when the printing job is completed, the automatic working process ends.

[0012] Furthermore, the mobile printing robot communicates with the terminal, receives and executes the control instructions issued by the terminal, and feeds back the robot status and automatic operation results; the laser positioning device tracks the positioning target ball on the printing robot, and measures the coordinates of the current mobile printing robot relative to the laser positioning device, and then sends position measurement information to the mobile printing robot.

[0013] Furthermore, in step 1, the mobile robot is started, and a command for the print head to return to zero is sent to the robot through the terminal. When the return to zero action is completed, the control unit automatically notifies the distance measuring sensor to measure the actual zero position of the print head.

[0014] Furthermore, the control unit performs several measurements and transmits the measurement data to the algorithm module for filtering to obtain accurate measurement values, and then calculates the actual zero-position deviation and stores it. When controlling the movement of the print head in subsequent operations, the deviation can be subtracted or added to the control amount to improve the accuracy of the spraying operation.

[0015] Furthermore, after the three-dimensional measuring device is started and initialized in step 1, the initial aiming of the reflection device and the three-dimensional measuring device is completed with manual assistance. After the initial aiming is completed, the mobile robot is started and initialized, and the three-dimensional measuring device sends the measured coordinate data of the reflection device to the mobile robot control unit in real time through the wireless communication device. The control unit parses and saves the received data. The data is parsed and saved when it is received for the first time. Starting from the second time the data is received, each time the rotation angle θ between two adjacent moments is calculated, and finally the reflection device is controlled to rotate the corresponding angle value to realize the active aiming of the reflection device to the three-dimensional measuring device.

[0016] Furthermore, the 3D measuring device can actively aim at the reflector, and the reflector reflects the laser beam within ±45°, so when θ is less than the threshold θ e, the reflection device is not rotated.

[0017] Furthermore, the method for calculating the rotation angle θ between two adjacent moments is as follows:

[0018] vector It can be calculated from the coordinates of the reflection device at A, that is, vector It can be calculated from the coordinates of the reflection device at B, that is, Further calculate the cross product vector of two vectors:

[0019]

[0020] Then the rotation angle θ can be calculated as:

[0021]

[0022] The result of the vector cross product It is a vector, which is defined as positive when the angle between its direction and the Z axis of the 3D measuring device is less than 90°, and negative when it is greater than 90°. The angle between the direction of and the Z axis of the three-dimensional measuring device is greater than 90°, so the value of θ is negative; it is defined that the reflection device is positive when it rotates counterclockwise around its central axis, and negative when it rotates clockwise.

[0023] The following beneficial effects can be obtained through the above technical solution:

[0024] The present invention utilizes an absolute positioning device to measure a reflection device installed at the end of a mobile robot, thereby optimizing the position accuracy of the mobile robot's spray printing positioning.

[0025] At the same time, the present invention calculates the actual zero position deviation, and can subtract or add the deviation to the control amount when controlling the movement of the print head in the subsequent operation process, so as to eliminate the system error and achieve the purpose of improving the operation accuracy.

[0026] The present invention can realize automatic aiming of the reflection device at the three-dimensional measuring device during the operation of the robot only through the measurement data of the three-dimensional measuring device, which can reduce the cost of the robot. The method is very simple and more importantly, has high accuracy and no cumulative error. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a flow chart of the present invention.

[0028] Figure 2 This is the system composition relationship diagram of the present invention

[0029] Figure 3 It is a schematic diagram of a mobile robot.

[0030] Figure 4 It is a coordinate diagram.

[0031] Figure 5 is a schematic diagram of the rotation angle θ. DETAILED DESCRIPTION

[0032] The present invention will be further described below in conjunction with the accompanying drawings:

[0033] like Figure 1 and 2 As shown, start the mobile robot, extract the straight lines (solid lines, dotted lines), circles, curves, symbols, texts, graphics, QR codes and color data information on the CAD drawings or BIM; determine the laser positioning placement, complete the leveling of the laser positioning equipment, and measure and track the position of the robot through the target ball installed on the robot; generate an automatic operation path: select the map to be operated, align the benchmark, map the map coordinate system to the ground operation area, edit the map to set obstacle information, select part or all of the operation range, set parameters, call the path planning algorithm to generate the operation path and printing process information; the robot performs printing in the operation area according to the operation path and printing process information; the printing operation is completed, and the automatic operation process ends.

[0034] The automatic operation route can avoid set obstacles. At the same time, during the movement of the robot, the ultrasonic sensor can sense the temporary appearance of people or other objects, as well as potholes around it in real time, stop at obstacles and activate voice alarm.

[0035] By operating the terminal APP terminal software, you can set parameters, display the robot status, coordinate position, movement speed, angular velocity; control the chassis, pan / tilt motor, traverse motor, inkjet test, import operation data, generate operation paths, and issue automatic operation tasks.

[0036] Mobile printing robot: The mobile printing robot communicates with the APP, receives and executes the control instructions under the APP, and feedbacks the robot status and automatic operation results; the laser positioning device tracks the positioning target ball on the printing robot, measures the coordinates of the current mobile printing robot relative to the laser positioning device, and then sends position measurement information to the mobile printing robot.

[0037] like Figure 3 As shown, in the embodiment of this patent, the spray printing system carried by the mobile robot is composed of a spray print head, a print head control mechanism, a print head lateral movement mechanism and a distance sensor. During the spraying operation, the mobile robot calculates the position of the print head in real time based on the received position information and the algorithm module in the control unit, and finally drives the spray print head to move along the print head lateral movement mechanism through the print head control mechanism to achieve the purpose of precise spraying operation. From the above description, it can be seen that the movement accuracy of the spray print head on the lateral movement mechanism plays a vital role in the operation accuracy.

[0038] like Figure 4 As shown in the figure, the robot's own coordinate system is constructed with the centers of the two wheels as the coordinate origin, the robot's central axis along the forward direction as the X-axis, and the Y-axis defined by the right-hand rule. Figure 4 L in the left figure represents the distance from the ranging sensor to the robot's X-axis, and the width of the print head is defined as W. When the mobile robot commands the spray print head to return to zero, according to the design and control principles, the print head should be on the central axis of the mobile robot, that is, the theoretical zero position of the print head. However, in actual operations, robots often have uncontrollable system errors, such as manufacturing errors, installation errors, errors caused by transportation vibrations, and wear of parts after long-term operation. When the mobile robot executes the return to zero command, if the actual zero position of the print head is not calibrated, but the theoretical zero position is still used, these errors will obviously be introduced in subsequent operations. Figure 4 As shown in the right figure, the actual zero position of the print head has deviated to the right from the center axis position. The zero position deviation at this time is:

[0039] e=d-L+w / 2

[0040] Where d is the actual measurement value of the distance sensor.

[0041] When e>0, it means that the distance from the actual zero position of the print head to the distance measuring sensor is larger than the theoretical zero position, and is close to the negative half axis of the robot's Y axis.

[0042] When e<0, it means that the distance from the actual zero position of the print head to the distance measuring sensor is smaller than the theoretical zero position, and is close to the positive half axis of the robot's Y axis.

[0043] After starting the mobile robot, a command to return the print head to zero can be sent to the robot through a portable computing device. When the return to zero action is completed, the control unit automatically notifies the distance measuring sensor to measure the actual zero position of the print head. Since the sensor often has measurement noise, the control unit will notify multiple measurements and pass the measurement data to the algorithm module for filtering to obtain a more accurate measurement value, and then further calculate the actual zero position deviation and store it. In the subsequent operation process, when controlling the movement of the print head, the deviation can be subtracted or added to the control amount to improve the accuracy of the spraying operation.

[0044] Figure 5 As shown, it is assumed that the reflection device of the mobile robot at position A has been accurately aimed, that is, the laser beam (indicated by the dotted line) emitted by the three-dimensional measuring device can be accurately reflected by the reflection device. When the mobile robot moves from position A to position B along an arbitrary trajectory, the reflection device undergoes a large position change around the origin of the three-dimensional measuring device, thereby causing a change in the mutual aiming direction between the reflection device and the three-dimensional measuring device. In order to enable the three-dimensional measuring device to quickly and accurately track the position of the measurement reflection device, the present invention actively controls the reflection device to rotate a certain angle θ so that it always faces the origin of the three-dimensional measuring device. The calculation method of the rotation angle θ is as follows:

[0045] vector It can be calculated from the coordinates of the reflection device at A, that is, vector It can be calculated from the coordinates of the reflection device at B, that is, Further calculate the cross product vector of two vectors:

[0046]

[0047] Then the rotation angle θ can be calculated as:

[0048]

[0049] The result of the vector cross product is a vector. The invention patent defines that when its direction is less than 90° with the Z axis of the 3D measuring device, it is positive, and when it is greater than 90°, it is negative. Figure 5 In the case shown in The angle between the direction of and the Z axis of the three-dimensional measuring device is greater than 90°, so the value of θ is negative. The present invention defines that the counterclockwise rotation of the reflection device around its central axis is positive, and the clockwise rotation is negative. Figure 5 In the case shown, θ is negative, so the origin of the three-dimensional measurement device can be actively aimed at by controlling the reflection device to rotate clockwise to a corresponding angle value.

[0050] It can be seen from the above calculation equation that the method of the present invention has the advantages of simple calculation, numerical stability, no cumulative error, no dependence on any other sensors, and no need to classify the robot's motion trajectory. It has application value in the scenario of positioning the mobile robot through three-dimensional equipment and reflection devices.

[0051] The specific solution is as follows: after starting the three-dimensional measuring device and initializing it, the initial aiming of the reflector and the three-dimensional measuring device is completed with manual assistance. After the initial aiming is completed, the mobile robot is started and initialized, and the three-dimensional measuring device sends the measured coordinate data of the reflector to the mobile robot control unit in real time through the wireless communication device. The control unit parses and saves the received data. It parses and saves the data when it is received for the first time. Starting from the second time the data is received, the rotation angle θ of two adjacent moments is calculated each time by the above equation. Finally, by controlling the reflector to rotate to the corresponding angle value, the reflector can be actively aimed at the three-dimensional measuring device. Furthermore, because the three-dimensional measuring device can actively aim at the reflector, and the reflector reflects the laser beam within ±45°, when |θ| is less than the threshold θ e (must be less than 45°), the reflection device does not need to be rotated.

[0052] Only through the measurement data of the three-dimensional measuring device, the reflection device can automatically aim at the three-dimensional measuring device during the operation of the robot, which can reduce the cost of the robot, and the method is very simple. More importantly, it has high accuracy and no cumulative error. The present invention includes a mobile robot and a three-dimensional measuring device. Typical three-dimensional measuring devices include total stations, trackers, position monitoring devices, etc. The three-dimensional measuring device emits a laser beam to illuminate a device with a reflection function on the mobile robot, and the device with a reflection function is fixed on the mobile robot, so as to reflect the position of the device in real time. The above-mentioned connection method is not limited to detachable or permanently fixed methods. The measurement information collected by the three-dimensional measuring device is transmitted to the mobile robot by wireless means, such as WIFI, radio waves, optics, etc. The transmission of the measurement information needs to have low latency and low packet loss rate, that is, real-time and accuracy of the transmission. Low latency can ensure that the mobile robot responds promptly and quickly, and accuracy can ensure that the trajectory of the mobile robot is closer to the theoretical value.

[0053] The above are all preferred embodiments of the present invention. For ordinary technicians in this technical field, without departing from the principle of the present invention, various equivalent modifications to the present invention belong to the protection scope of the claims attached to this application.

Claims

1. A mobile robot printing method, characterized in that: The method is as follows: Step 1: Start and initialize the mobile robot, automatically calibrate the zero position of the spray print head, and extract data information of the operation map; Step 2: Determine the laser positioning position, complete the leveling of the laser positioning equipment, and measure and track the position of the robot through the target ball installed on the robot; Step 3: Generate automatic operation path: select the map to be operated, align the benchmark, map the map coordinate system to the ground operation area, edit the map to set obstacle information, select part or all of the operation range, set parameters, call the path planning algorithm to generate the operation path and print process information; Step 4: The robot performs printing in the working area according to the working path and printing process information; The print job is completed, ending the automatic job process.

2. A mobile robot printing method according to claim 1, characterized in that: The mobile printing robot communicates with the terminal, receives and executes the control instructions issued by the terminal, and feeds back the robot status and automatic operation results; the laser positioning device tracks the positioning target ball on the printing robot, measures the coordinates of the current mobile printing robot relative to the laser positioning device, and then sends position measurement information to the mobile printing robot.

3. A mobile robot printing method according to claim 1, characterized in that: In step 1, the mobile robot is started, and a command for the print head to return to zero is sent to the robot through the terminal. When the return to zero action is completed, the control unit automatically notifies the distance measuring sensor to measure the actual zero position of the print head.

4. A mobile robot printing method according to claim 3, characterized in that: The control unit performs several measurements and transmits the measurement data to the algorithm module for filtering to obtain accurate measurement values, and then calculates the actual zero position deviation and stores it. When controlling the movement of the print head in subsequent operations, the deviation can be subtracted or added to the control amount to improve the accuracy of the spraying operation.

5. A mobile robot printing method according to claim 1, characterized in that: After the three-dimensional measuring device is started and initialized in step 1, the initial aiming of the reflector device and the three-dimensional measuring device is completed with manual assistance. After the initial aiming is completed, the mobile robot is started and initialized, and the three-dimensional measuring device sends the measured reflector device coordinate data to the mobile robot control unit in real time through the wireless communication device. The control unit parses and saves the received data. The data is parsed and saved when it is received for the first time. Starting from the second time the data is received, each time the rotation angle θ between two adjacent moments is calculated, and finally the reflector device is controlled to rotate the corresponding angle value to realize the active aiming of the reflector device to the three-dimensional measuring device.

6. A mobile robot printing method according to claim 5, characterized in that: The 3D measurement device can actively aim at the reflector, and the reflector reflects the laser beam within ±45°, so when |θ| is less than the threshold θ e The reflector device is not rotated.

7. A mobile robot printing method according to claim 5, characterized in that: The method for calculating the rotation angle θ between two adjacent moments is as follows: vector It can be calculated from the coordinates of the reflection device at A, that is, vector It can be calculated from the coordinates of the reflection device at B, that is, Further calculate the cross product vector of the two vectors: Then the rotation angle θ can be calculated as: The result of the vector cross product It is a vector, which is defined as positive when the angle between its direction and the Z axis of the 3D measurement device is less than 90°, and negative when it is greater than 90°. The angle between the direction of and the Z axis of the three-dimensional measuring device is greater than 90°, so the value of θ is negative; it is defined that the counterclockwise rotation of the reflection device around its central axis is positive, and the clockwise rotation is negative.

8. A mobile robot printing method according to claim 1, characterized in that: The data information includes one or more combinations of straight lines, circles, curves, symbols, text, graphic information and colors.

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