A lawn mowing robot control system and control method

Abstract

The present invention discloses a lawn mowing robot control system and control method, relating to the field of robot control technology. The control system includes: an industrial computer, a positioning module, and a control module; the industrial computer is connected to the control module and the positioning module; the industrial computer transmits control instructions to the control module and the positioning module; the positioning module includes a laser scanning module, a measurement and positioning module, and a visual analysis module, wherein the visual analysis module identifies obstacles, and based on the identification results, measures the distance between the lawn mowing robot and the obstacle in real time through the laser scanning module, and automatically navigates and performs obstacle avoidance operations according to the obstacle avoidance path through the measurement and positioning module and the control module; the control module is used to receive control instructions to control the drive device and input and output devices. Through the obstacle avoidance and positioning functions, the present invention can accurately and automatically identify and operate obstacles and plants to be cut, thereby improving environmental adaptability and reducing the probability of missed or incorrect cutting.

Description

Technical Field

[0001] The present invention relates to the technical field of robot control, and in particular to a lawn mowing robot control system and a control method. Background Art

[0002] The statements in this section merely provide background information related to the present invention and do not necessarily constitute prior art.

[0003] With the rapid development of intelligent machines, mobile robots have found widespread application in agriculture. However, mowing still primarily relies on traditional handheld internal combustion engine lawn mowers. Due to the high labor intensity and repetitive nature of mowing, robots are more suitable for this type of work than traditional manual labor. However, mowing is subject to numerous uncertainties, making robots ineffective. These uncertainties primarily include complex mowing terrain, unstable battery life, and unknown cutting targets. While mowing robots are primarily used in public green spaces and agricultural production, their practical application requires consideration of a wide range of operating conditions.

[0004] Most existing robotic lawn mowers have complex mechanical structures, high hardware costs, and are prone to environmental pollution. Furthermore, most current robotic lawn mowers are designed for use on flat ground and cannot operate at full speed on slopes. Long operating times also reduce their battery life, lowering efficiency and limiting their applicability. Some robots also experience errors when identifying plants to cut, resulting in missed or mis-cuts. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention provides a robotic lawn mower control system and method. This system utilizes a DC motor as its primary driving force, resulting in minimal mowing pollution. Through obstacle avoidance and positioning capabilities, the robot accurately identifies obstacles and the plants it needs to cut, improving its adaptability to environmental conditions and reducing the chance of missed or incorrect cuts.

[0006] In order to achieve the above object, the present invention is implemented through the following technical solutions:

[0007] A first aspect of the present invention provides a lawn mowing robot control system, comprising:

[0008] An industrial computer, a positioning module and a control module; the industrial computer is connected to the control module and the positioning module; the industrial computer is used to receive signals from each module and generate control instructions after processing the signals, and the industrial computer transmits the control instructions to the control module and the positioning module; the positioning module includes a laser scanning module, a measurement and positioning module and a visual analysis module, wherein the visual analysis module identifies obstacles, and according to the identification results, the distance between the lawn mowing robot and the obstacle is measured in real time through the laser scanning module, and the lawn mowing robot automatically navigates and performs obstacle avoidance operations according to the obstacle avoidance path through the measurement and positioning module and the control module; the control module is used to receive control instructions from the industrial computer and control the drive equipment and input and output devices according to the control instructions.

[0009] Furthermore, the specific steps for the visual analysis module to identify obstacles are as follows:

[0010] Obtain obstacle images and perform color and shape recognition on the obstacle images;

[0011] If a plant suitable for cutting is identified, the cutting operation is carried out according to the path planning;

[0012] If uncuttable plants are identified, they are recorded as obstacles and obstacle avoidance is performed.

[0013] Furthermore, the specific steps of automatically navigating and performing obstacle avoidance operations according to the obstacle avoidance path through the measurement and positioning module and the control module are as follows:

[0014] Obtain the distance between the mowing robot and obstacles obtained by the laser scanning module in real time;

[0015] When the distance between the mowing robot and the obstacle reaches the set minimum distance;

[0016] The control module controls the mowing robot to turn and avoid obstacles, and selects the path in real time according to the dynamic window algorithm (DWA);

[0017] After completing the turn to avoid the obstacle, continue driving along the planned path.

[0018] Furthermore, the specific steps for selecting a path in real time according to the dynamic window algorithm are as follows:

[0019] The dynamic window algorithm traverses all trajectories between the maximum angle and the minimum angle, and selects the optimal trajectory based on the set heading score, distance score, and speed score.

[0020] Furthermore, when the obstacle is too large to be avoided by a single turn, the control module controls the mowing robot to locate itself according to the measurement and positioning module and to travel along the obstacle at a set distance.

[0021] Furthermore, the laser scanning module adopts SLAM based on laser radar to scan obstacles in the planned path and build a map in real time. When the existence of an obstacle is scanned, the target trajectory and map information are updated in real time to bypass the obstacle.

[0022] Furthermore, a remote control module is included, which includes a remote controller and a wireless communication module. The remote controller is connected to the control module via the wireless communication module and is used for wireless remote control of the lawn mowing robot.

[0023] Furthermore, it also includes a host computer, which is a PC device connected to the industrial computer and is used to monitor the control status of the lawn mowing robot.

[0024] Furthermore, it also includes a battery management module, which is a BMS battery management system connected to the industrial computer and is used to provide power and manage the power.

[0025] A second aspect of the present invention provides a control method for a lawn mowing robot, comprising the following steps:

[0026] Acquire the working environment and build a map;

[0027] Scan the working environment and identify and classify the scanned objects according to the cutting standards; treat the scanned objects that cannot be cut as obstacles and the scanned objects that can be cut as cutting targets;

[0028] Path planning based on the distribution of obstacles and cutting targets;

[0029] Control the mowing robot to perform cutting and obstacle avoidance operations according to path planning.

[0030] One or more of the above technical solutions have the following beneficial effects:

[0031] This invention discloses a control system and method for a lawn mower robot. While traditional lawn mowers powered by internal combustion engines consume fuel and have low energy conversion rates, resulting in unnecessary energy waste, this new robot utilizes a DC motor as the primary driving force, resulting in minimal lawn mowing pollution. Through obstacle avoidance and positioning capabilities, this robot accurately identifies obstacles and plants to be cut, and creates a map and performs path planning based on the overall working environment, improving its environmental adaptability and reducing the chance of missed or erroneous cuts.

[0032] Advantages of additional aspects of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The accompanying drawings, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0034] Figure 1 This is a framework diagram of the control system of the lawn mowing robot in Example 1 of the present invention;

[0035] FIG2( a ) is a diagram showing the overall structure of the lawn mowing robot in the first embodiment of the present invention;

[0036] FIG2( b ) is a rear view of the lawn mowing robot in the first embodiment of the present invention;

[0037] FIG2( c ) is a top view of the lawn mowing robot in the first embodiment of the present invention;

[0038] FIG2( d ) is a side view of the lawn mowing robot in the first embodiment of the present invention;

[0039] Figure 3 This is a schematic diagram of controlling the height adjustment of the mowing disc of a lawn mowing robot in the first embodiment of the present invention.

[0040] Figure 4 This is a schematic diagram of control when the control system detects a small obstacle in Example 1 of the present invention;

[0041] Figure 5 Schematic diagram of controlling the steering and steering angle of the lawn mowing robot in the first embodiment of the present invention;

[0042] Figure 6 This is a schematic diagram of controlling the lawn mowing robot to turn and avoid obstacles in the first embodiment of the present invention;

[0043] Figure 7 This is a schematic diagram of controlling the lawn mowing robot to reverse direction in the first embodiment of the present invention;

[0044] Figure 8 This is a schematic diagram of controlling the lawn mowing robot to move forward in the first embodiment of the present invention;

[0045] Figure 9 This is a schematic diagram of control when the control system detects a large obstacle in Example 1 of the present invention;

[0046] Figure 10 This is a schematic diagram of controlling a lawn mowing robot to move along an obstacle in the first embodiment of the present invention;

[0047] Figure 11 This is a schematic diagram of force analysis when running upward on a slope in the first embodiment of the present invention;

[0048] Figure 12 This is a schematic diagram of force analysis when running downward uphill in Example 1 of the present invention. DETAILED DESCRIPTION

[0049] It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present application belongs.

[0050] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is intended to include the plural form. In addition, it should be understood that when the terms "include" and / or "comprising" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or their combinations;

[0051] Example 1:

[0052] The first embodiment of the present invention provides a lawn mowing robot control system, such as Figure 1 Shown, including:

[0053] The system consists of an industrial computer, a positioning module, a remote control module host computer, a battery management module, and a control module. The industrial computer is connected to the control module and the positioning module. The industrial computer receives signals from each module, processes them, and generates control commands, which it then transmits to the control module and the positioning module. The positioning module includes a laser scanning module, a measurement and positioning module, and a visual analysis module. The visual analysis module identifies obstacles and uses the laser scanning module to measure the distance between the robot and obstacles in real time based on the identification results. The robot then automatically navigates along an obstacle avoidance path and performs obstacle avoidance operations using the measurement and positioning module and the control module. The control module receives control commands from the industrial computer and controls the drive devices and input and output components accordingly. The remote control module includes a remote controller and a wireless communication module. The remote controller connects to the control module via the wireless communication module and is used for wireless remote control of the robot. The host computer is a PC connected to the industrial computer and monitors the robot's control status. Path planning and debugging are performed through the host computer. The battery management module, a conventional BMS (Battery Management System), connects to the industrial computer via Bluetooth. It provides power and manages the power supply, enabling intelligent management and maintenance of each battery cell, preventing overcharge and over-discharge, extending battery life, and monitoring battery status. In this embodiment, lithium batteries serve as the primary power source for the robot's control modules. This embodiment employs a redundant power supply design, utilizing both solar charging and low-voltage external power charging. This, in conjunction with the BMS power management system, extends the robot's operating time.

[0054] In one specific embodiment, the controller receives signals from a wireless remote control and an industrial computer, and sends signals to the DC motor, servo, and servo linear motor. The controller also controls the connection of input and output components such as angle sensors and encoders, and implements speed control through speed feedback. The drive device includes a driver, an analog encoder, a DC motor, a servo, and a servo linear motor. In this embodiment, the industrial computer primarily implements intelligent control of the lawn mower robot. In the event of conflicting commands between the remote control and the industrial computer, the remote control's command takes precedence.

[0055] The DC motor realizes the steering and provides the main power for the mower robot. The DC motor consists of a steering motor and a main motor. The steering motor realizes the steering movement of the mower robot, while the main motor simultaneously realizes the walking and mowing movements of the mower robot. The driver provides driving power for the DC motor. In this embodiment, the DC motor and hydraulic pump are used to simultaneously provide power for the walking and mowing blades.

[0056] The servos are brake clutch servos and variable pump servos. The lawn mower robot in this embodiment has a single main motor, and its structure is shown in Figures 2(a), 2(b), 2(c) and 2(d). In this embodiment, only a lawn mower robot with an existing single main motor structure is provided. At the same time, the technical solution of the present invention can also be applied to other single main motor robots. The power of the lawn mower disc and the walking power of the robot are both realized by DC motors and servos. The servos include brake clutch servos and variable pump servos. The variable pump servos realize the speed control of the lawn mower disc. The steering motor realizes the steering action of the lawn mower robot and feeds back the steering angle to the magnetic encoder. The brake clutch servo realizes the braking and deceleration action of the robot to achieve the function of main shaft braking control.

[0057] The servo linear motor enables the height of the mowing disc of the mowing robot to be adjusted to suit different working environments, such as Figure 3 The servo motor's height control information comes from the staff's settings. After the mowing height is set, the linear servo motor adjusts the height of the mowing disc.

[0058] The analog encoder is a magnetic encoder, enabling control of the robot's angle. This magnetic encoder controls turning angles, and in conjunction with the SLAM laser scanning module, the RTK positioning of the measurement and positioning module, and the vision analysis module's visual solution, enables path planning and obstacle avoidance. The PLC controls and monitors the robot's operating angle, speed, and mowing disc height.

[0059] In one specific embodiment, the control module is a PLC controller. The processor of this embodiment communicates information between the various modules using a 485 bus. The PLC controller receives control commands from an industrial computer and transmits them to drivers, input / output components, and the like. The motor driver converts the controller's signals into electrical drive signals to drive DC motors, steering gears, and servo linear motors. Input / output components include switches and sensors. The controller exchanges data with these input / output (IO) components to start and stop the robot. If the robot fails to follow instructions due to factors such as the working environment, timely protective measures such as collision warnings and emergency stops are implemented.

[0060] In a specific embodiment, the remote controller wirelessly sends input and output control signals such as start and stop, travel and steering operation signals, working mode adjustment signals, power-on self-test and fault detection signals, etc. to the controller.

[0061] In one specific embodiment, visual analysis utilizes a visual camera solution. Using digital image processing technology, the robot mower's working environment is characterized by identifying obstacles in its path. If an obstacle is present, the robot avoids the obstacle; otherwise, the robot follows the planned path. Obstacle images are captured and their color and shape are identified. If suitable plants are identified, the robot cuts according to the planned path. If uncuttable plants (commonly lawn shrubs) are identified, they are marked as obstacles and obstacle avoidance is performed.

[0062] Color and shape recognition of obstacle images is achieved through digital image processing:

[0063] The collected obstacle images are preprocessed by grayscale conversion and filtering.

[0064] The preprocessed image is binarized using the maximum between-class variance method (OTSU). The OTSU algorithm is an efficient image binarization algorithm that uses a threshold to separate the original image into two images: foreground and background. The basic idea is to divide the image into two types based on a certain threshold: one in which the grayscale of all image pixels is lower than this threshold, and the other in which the grayscale of all image pixels is greater than or equal to this threshold. If the grayscale difference between the two types of pixels is large, it indicates that the threshold value obtained is effective for image segmentation. Using this threshold value, the image can be divided into two areas: lawn and obstacle.

[0065] In one specific implementation, the laser scanning module uses LiDAR-based Simultaneous Localization and Mapping (SLAM) to scan for obstacles along a planned path and construct a map in real time. When an obstacle is detected, the target trajectory and map information are updated in real time to circumvent the obstacle. Specifically, the target trajectory uses a DWA algorithm to select the optimal path through real-time path planning, and the SLAM LiDAR and GPS positioning are used to map the target in real time to update the obstacle information on the map.

[0066] Furthermore, the Dynamic Window Approach (DWA) algorithm is a local path planning algorithm commonly used for local obstacle avoidance. The DWA algorithm traverses all trajectories between the maximum and minimum angles, selects the optimal trajectory based on the set heading score, distance score, and speed score, and also determines the steering angle used during obstacle avoidance.

[0067] LiDAR is based on time of flight, which measures the distance by measuring the flight time of the laser: Where d is the distance, c is the speed of light, and t is the time interval from transmission to reception. The laser radar consists of a transmitter and a receiver. The transmitter illuminates the target with laser light, and the receiver receives the reflected light waves and obtains the distance between the mowing robot and the obstacle in real time from the laser scanning module. When the distance between the robot and the obstacle reaches the set minimum distance, such as Figure 4 As shown, the control module controls the mowing robot to turn to avoid obstacles, and the steering angle is a, as shown in Figure 5 As shown in Figure 1, the steering angle control is monitored by a magnetic encoder. The robot plans the path in real time according to the DWA algorithm and selects its optimal path. The steering angle a also changes in real time, as shown in Figure 1. Figure 6 As shown, after driving to a point where it is safe to avoid obstacles, reverse steering is performed, as shown in Figure 7 After turning, continue driving to complete the obstacle avoidance, as shown in Figure 8 When the obstacle is too large to avoid by turning, as shown in Figure 9 As shown in Figure 2, the control module controls the mowing robot to locate according to the measurement and positioning module, and to drive along the obstacle according to the set distance according to the A* (A-Star) algorithm, as shown in Figure 2. Figure 10 As shown in the figure, the map is constructed and obstacle avoidance is finally achieved. The A-Star algorithm is the most effective direct search method for finding the shortest path in a static road network.

[0068] In one specific implementation, the measurement and positioning module uses real-time kinematic (RTK) positioning technology, specifically using GPS and Internet positioning, to ensure accurate positioning. The work area is planned on a PC, and the SLAM module is used to improve the map obstacle and record the operation trajectory, enabling automatic navigation and obstacle avoidance.

[0069] There is a body tilt sensor on the robot body. When the slope is small (less than 15°), the robot can be driven by the main motor to climb the slope because the mechanical structure of the robot adopts a hydraulic variable pump drive. When the slope is large (greater than 15°), a winch is used to assist in climbing. The force that should be matched to the winch at different angles is calculated. The schematic diagrams of the upward and downward movements and their force analysis are shown below. Figure 11 、 12 As shown, the inclination angle is b, F is the driving force, Fd is the motor driving force, Fj is the winch driving force, Fa is the acceleration resistance, Fp is the ramp resistance, Ff is the rolling resistance, f is the rolling friction coefficient, m is the mass of the robot, and a is the acceleration.

[0070] Ff=f·Fn

[0071] Fa=m·a

[0072] Fp=G·sinb

[0073] When the robot moves upward at a constant speed, the robot wheels and the winch work together to make the robot move upward. According to the force analysis, we can get:

[0074] Ff+Fa+Fp=Fd+Fj,

[0075] When the robot moves downward at a constant speed, the upward driving force of the winch causes the robot to move downward. According to the force analysis, it can be obtained that:

[0076] Fd+Fj+Fp=Ff+Fa.

[0077] Example 2:

[0078] A second embodiment of the present invention provides a control method for a lawn mowing robot, comprising the following steps:

[0079] Acquire the working environment and build a map;

[0080] Scan the working environment and identify and classify the scanned objects according to the cutting standards; treat the scanned objects that cannot be cut as obstacles and the scanned objects that can be cut as cutting targets;

[0081] Path planning based on the distribution of obstacles and cutting targets;

[0082] Control the mowing robot to perform cutting and obstacle avoidance operations according to path planning.

[0083] The steps involved in the above embodiment 2 correspond to those in the method embodiment 1. For the specific implementation method, please refer to the relevant description part of the embodiment 1.

[0084] Although the above describes the specific embodiments of the present invention in conjunction with the accompanying drawings, it is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art on the basis of the technical solution of the present invention without any creative work are still within the scope of protection of the present invention.

Claims

1. A lawn mowing robot control system, characterized in that: include: An industrial computer, a positioning module, and a control module; the industrial computer is connected to the control module and the positioning module; the industrial computer is used to receive signals from each module and generate control instructions after processing the signals, and the industrial computer transmits the control instructions to the control module and the positioning module; the positioning module includes a laser scanning module, a measurement and positioning module, and a visual analysis module, wherein the visual analysis module identifies obstacles, and based on the identification results, the laser scanning module measures the distance between the mowing robot and the obstacle in real time, and the measurement and positioning module and the control module automatically navigate and perform obstacle avoidance operations according to the obstacle avoidance path; the specific steps of automatically navigating and performing obstacle avoidance operations according to the obstacle avoidance path by the measurement and positioning module and the control module are as follows: Obtain the distance between the mowing robot and obstacles obtained by the laser scanning module in real time; When the distance between the mowing robot and the obstacle reaches the set minimum distance; The control module controls the mowing robot to turn and avoid obstacles, and selects the path in real time based on the dynamic window algorithm; After completing the steering and obstacle avoidance, continue driving along the planned path; The specific steps for selecting a path in real time according to the dynamic window algorithm are as follows: The dynamic window algorithm traverses all trajectories between the maximum angle and the minimum angle, and selects the optimal trajectory based on the set heading score, distance score, and speed score; The control module is used to receive control instructions from the industrial computer and control the drive equipment and input and output devices according to the control instructions.

2. The lawn mowing robot control system according to claim 1, characterized in that: The specific steps for the visual analysis module to identify obstacles are: Obtain obstacle images and perform color and shape recognition on the obstacle images; If a plant suitable for cutting is identified, the cutting operation is carried out according to the path planning; If uncuttable plants are identified, they are recorded as obstacles and obstacle avoidance is performed.

3. The lawn mowing robot control system according to claim 1, wherein: When the obstacle is too large to be avoided by turning once, the control module controls the mowing robot to locate according to the measurement and positioning module and travel along the obstacle according to the set distance.

4. The lawn mowing robot control system according to claim 1, wherein: The laser scanning module adopts SLAM based on laser radar to scan obstacles in the planned path and build a map in real time. When the existence of an obstacle is scanned, the target trajectory and map information are updated in real time to bypass the obstacle.

5. The lawn mowing robot control system according to claim 1, wherein: It also includes a remote control module, which includes a remote controller and a wireless communication module. The remote controller is connected to the control module via the wireless communication module and is used for wireless remote control of the lawn mowing robot.

6. The lawn mowing robot control system according to claim 1, wherein: It also includes a host computer, which is a PC device connected to the industrial computer and is used to monitor the control status of the lawn mowing robot.

7. The lawn mowing robot control system according to claim 1, wherein: It also includes a battery management module, which is a BMS battery management system connected to the industrial computer and is used to provide power and manage the power.

8. A control method based on the lawn mowing robot control system according to any one of claims 1 to 7, comprising the following steps: Acquire the working environment and build a map; Scan the working environment and identify and classify the scanned objects according to the cutting standards; treat the scanned objects that cannot be cut as obstacles and the scanned objects that can be cut as cutting targets; Path planning based on the distribution of obstacles and cutting targets; Control the mowing robot to perform cutting and obstacle avoidance operations according to path planning.

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