Robot repositioning method based on specific medium area, robot and chip

Abstract

This invention discloses a robot relocalization method, a robot, and a chip based on a specific medium region. At least two ultrasonic sensors are fixedly mounted on both sides of the robot's bottom. The robot relocalization method includes step 1: the robot walks within the specific medium region to the boundary line of the specific medium region, and then adjusts the two ultrasonic sensors to be positioned on either side of the boundary line of the specific medium region; step 2: the robot walks while maintaining the two ultrasonic sensors positioned on either side of the boundary line of the specific medium region, so that the robot walks along the boundary line of the specific medium region until it reaches a corner point. The pose information of the corner point is then used to update the robot's current pose information, completing the robot's relocalization. The pose information of each boundary line forming the specific medium region is pre-stored in the robot's memory, and the corner point is the endpoint of the boundary line forming the specific medium region.

Description

Technical Field

[0001] This invention relates to the technical field of robot relocation, and in particular to a robot relocation method, robot, and chip based on a specific medium region. Background Technology

[0002] In indoor environments, robotic vacuum cleaners may experience walking errors during cleaning due to slippage of inertial sensors such as gyroscopes or encoders on carpet surfaces. These errors accumulate over time, leading to significant inaccuracies in the map built by the robot. For example, the map may be inaccurate or even fail to close boundaries. Therefore, to overcome these errors, if the robotic vacuum cleaner does not calculate its own pose information (including position coordinates and angles) on flexible surfaces such as carpets and does not build a map in real time, it will lose its pose information on the carpet surface, which is detrimental to path planning and navigation after leaving the carpet. Summary of the Invention

[0003] To obtain the position of a robot in a slippery surface area, this invention discloses a robot relocalization method based on a specific surface area. This method is applicable to relocalization operations performed after a robot has traversed a specific slippery surface area. The specific technical solution is as follows: A robot relocalization method based on a specific medium region is applicable to robots equipped with inertial sensors and ultrasonic sensors. At least two ultrasonic sensors are fixedly mounted on both sides of the robot's bottom, located on either side of the robot's central axis, which is parallel to the direction of travel. Before executing the relocalization method, the robot travels within the specific medium region. The relocalization method includes: Step 1, the robot travels within the specific medium region to the boundary line of the region, and then adjusts the two ultrasonic sensors to be positioned on either side of the boundary line; Step 2, the robot continues to travel along the boundary line while maintaining the two ultrasonic sensors positioned on either side of the boundary line, until it reaches a corner point. The pose information of this corner point is then used to update the robot's current pose information, completing the relocalization. The pose information of each boundary line forming the specific medium region is pre-stored in the robot's memory, and the corner point is the endpoint of the boundary line forming the specific medium region.

[0004] Further, in step 1, the method of adjusting the two ultrasonic sensors to be positioned on opposite sides of the boundary line of the specific medium area includes: when the robot walks to the boundary line of the specific medium area, the robot rotates its body to adjust its walking direction until the intensity of the ultrasonic reflected signal received by the first ultrasonic sensor is not within a preset intensity threshold range, the intensity of the ultrasonic reflected signal received by the second ultrasonic sensor is within a preset intensity threshold range, and the attitude angle measured by the inertial sensor is less than or equal to a preset angle threshold. Then, the robot does not detect the specific medium area on the side corresponding to the first ultrasonic sensor, and the robot detects the specific medium area on the side corresponding to the second ultrasonic sensor, thereby determining that the robot is in a state where the two ultrasonic sensors are positioned on opposite sides of the boundary line of the specific medium area. The preset angle threshold is determined by the inverse trigonometric function result of the maximum allowable height that the robot can cross over the obstacle. The two ultrasonic sensors are the first ultrasonic sensor and the second ultrasonic sensor, respectively. The first ultrasonic sensor and the second ultrasonic sensor are fixedly mounted on opposite sides of the robot's central axis.

[0005] Further, in step 1, the method for determining the boundary line of the specific medium area where the robot walks within the specific medium area includes determining that the robot has walked to the boundary line of the specific medium area when the intensity of the ultrasonic reflected signal received by the ultrasonic sensor is not within a preset intensity threshold range during the robot's movement within the specific medium area; wherein, the preset intensity threshold range is a pre-set signal intensity threshold range used to represent the signal intensity range of the ultrasonic reflected signal fed back from the specific medium area; wherein, the ultrasonic sensor is a first ultrasonic sensor or a second ultrasonic sensor.

[0006] Further, in step 2, the robot walks while maintaining the two ultrasonic sensors positioned on either side of the boundary line of the specific medium region, allowing the robot to walk along the boundary line of the specific medium region until it reaches a corner point. The method of updating the robot's current pose information using the pose information of this corner point includes: starting from the position point where the robot initially maintains the two ultrasonic sensors positioned on either side of the boundary line of the specific medium region, the robot walks in a preset clockwise direction to maintain its position along the boundary line of the specific medium region, and uses an inertial sensor to detect the angle change; when the robot detects that the angle change reaches a reference angle, the robot reaches the corner point, and the pose information of this corner point is used to update the robot's current pose information, thereby enabling the robot to regain its pose information within the specific medium region; wherein, the angle change is the change in the robot's heading angle, used to represent the change in the robot's walking direction; wherein, the corner point is the common endpoint of the two boundary lines of the specific medium region, and is a position point where the robot maintains its movement along the boundary line of the specific medium region by rotating the reference angle; wherein, the preset clockwise direction is either clockwise or counterclockwise.

[0007] Further, in step 1, before adjusting the two ultrasonic sensors to be positioned on either side of the boundary line of the specific medium area, the robot walks along the target direction to the target boundary line within the specific medium area; wherein, the target direction is within the angle formed by the lines connecting the preset starting point and the two endpoints of the target boundary line; wherein, the target direction is the walking direction of the robot when it begins to execute the robot relocation method, or the direction that forms a preset target angle with the walking direction of the robot when it begins to execute the robot relocation method; the target boundary line is any boundary line that encloses the specific medium area; wherein, the preset starting point is the starting position point of the robot's movement within the specific medium area before executing the robot relocation method; the preset starting point is a pre-set fixed position point; the orientation information of each boundary line enclosing the specific medium area relative to the preset starting point is pre-obtained fixed information.

[0008] Furthermore, the reference angle is the angle between the target boundary line and its boundary line connected in a preset clockwise direction, and the corner point is the common endpoint of the target boundary line and its boundary line connected in a preset clockwise direction; wherein, the planar shape of the specific medium region is a polygon, the corner point is a vertex of the polygon, and the boundary line is an edge of the polygon, such that each boundary line of the specific medium region is a straight line segment.

[0009] Furthermore, the specific medium region is a rectangular region whose surface is covered with a specific medium, the corner point is the vertex of the rectangular region, and the reference angle is 90 degrees, so that after the robot rotates a right angle in a preset clockwise direction, the pose information of the vertex of the right angle is used to update the robot's current pose information; wherein, the pose information of the vertex of the right angle includes the coordinate information and angle information of the vertex of the right angle; each side of the rectangular region is a boundary line, and the rectangular region is enclosed by four boundary lines.

[0010] Furthermore, when the robot detects an angle change reaching the reference angle from the repositioning starting point, it determines that the robot has walked to the corner point and rotated through the reference angle in a preset clockwise direction at the corner point. Then, the robot uses the pose information of the corner point to update the robot's current pose information. Here, the repositioning starting point is the position point where the robot begins to maintain the state where the two ultrasonic sensors are located on both sides of the boundary line of the specific medium region. Here, the corner point and the repositioning starting point are located on the same boundary line of the specific medium region, which is located between the two ultrasonic sensors. Among the two ultrasonic sensors, one ultrasonic sensor is located above the specific medium region, and the other ultrasonic sensor is located above an area outside the specific medium region.

[0011] Furthermore, when the robot walks within the specific medium area, the robot controls the ultrasonic sensor to emit ultrasonic waves and receive reflected ultrasonic signals, and controls the inertial sensor to measure the robot's attitude angles, but stops marking the grid on the global map; after the robot updates its current pose information using the pose information of the corner points, the robot walks to an area outside the specific medium area, and at the same time, the robot acquires its pose information and marks the corresponding grid in the global map; wherein, the surface covering medium of the area outside the specific medium area is different from the specific medium covering the surface of the specific medium area; wherein, the specific medium area is a closed area that causes the robot to slip.

[0012] A robot is provided, the robot being equipped with at least one inertial sensor, at least two ultrasonic sensors, and at least one processor, wherein at least two ultrasonic sensors are fixedly mounted on both sides of the bottom of the robot, and are located on both sides of the robot's central axis, the robot's central axis being parallel to the direction of travel; the processor is used to control the robot to execute the robot repositioning method.

[0013] A chip storing a program that, when executed by the chip, implements the robot relocation method.

[0014] The present invention relates to a robot that, after cleaning a carpet, moves along the boundary of a specific media area by keeping its ultrasonic sensors on both sides positioned on either side. Based on this boundary, the robot searches for a corner point within the area by measuring angular changes, thus repositioning its current location to the location of that corner point recorded on the map. This improves the accuracy of the repositioning calculation while reducing computational load. It avoids mapping errors caused by the robot's drive wheels slipping on the carpet surface and facilitates subsequent path planning using the accurately repositioned location. Attached Figure Description

[0015] Figure 1 This is a flowchart of a robot relocation method based on a specific medium region, as disclosed in one embodiment of the present invention. Detailed Implementation

[0016] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application may also be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods have been omitted so as not to obscure the description of this application with unnecessary detail.

[0017] It should be understood that, when used in this application, the term "comprising" indicates the presence of the described feature, integral, step, operation, element, and / or component, but does not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components, and / or collections thereof. It should also be understood that, as used in this application, the term "and / or" refers to any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0018] As used in this application, the term "if" may be interpreted, depending on the context, as "when," "once," "in response to determination," or "in response to detection." Similarly, the phrase "if determined" or "if [the described condition or event] is detected" may be interpreted, depending on the context, as "once determined," "in response to determination," "once [the described condition or event] is detected," or "in response to detection of [the described condition or event]."

[0019] Furthermore, in the description of this application, the terms "first," "second," "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance. References to "one embodiment" or "some embodiments" in this specification mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized.

[0020] It's important to note that while inertial sensor navigation is a low-cost and practical method for intelligent mobile robots, it also has significant drawbacks, primarily low navigation accuracy. Gyroscope drift and encoder drift are the main causes affecting navigation accuracy. During the operation of a robotic vacuum cleaner, complex factors such as wheel slippage can cause errors in the gyroscope and encoder. If these errors are not corrected, the robot will gradually deviate from its path. Considering that when the robot is in a normal operating state, the drive wheels propel the robot's displacement, meaning the distance traveled by the drive wheels is consistent with the robot's displacement, if the robot is slipping, the drive wheels will rotate, but the robot's displacement will remain unchanged.

[0021] Inertial navigation is a low-cost and practical navigation method for intelligent mobile robots, but its drawbacks are also significant, primarily manifested in low navigation accuracy. Gyroscope drift and encoder drift are the main causes affecting navigation accuracy. When intelligent mobile robots operate on soft surfaces such as carpets (floor coverings in indoor environments), complex factors such as wheel slippage cause errors in the gyroscope and encoder. Accumulated errors over time lead to significant inaccuracies in the map constructed by the robot, such as map deviations. If these errors are not corrected, the intelligent mobile robot will gradually deviate from its path; the longer the robot travels, the greater the errors become. Furthermore, if the intelligent mobile robot chooses not to calculate its own pose information (including position coordinates and angles) on soft surfaces like carpets and does not build a map in real time (i.e., does not add new grids to the global map), it will lose its pose information (including position coordinates) on the carpet surface. In order to re-acquire its own pose information (i.e., relocalization) when the robot is about to leave the carpet for path planning in areas outside the carpet, this invention discloses a robot relocalization method based on a specific medium region. This robot relocalization method is applicable to robots equipped with inertial sensors and ultrasonic sensors. The inertial sensors are located inside the robot and include an encoder, an accelerometer, and a gyroscope. The accelerometer is a sensor that senses axial acceleration and converts it into a usable output signal; the gyroscope is a sensor that can sense the angular velocity of the robot's motion in a specific medium region. The encoder, accelerometer, and gyroscope form an inertial navigation system, which is an autonomous navigation system that does not rely on external information and does not radiate energy to the outside. In this embodiment, at least two ultrasonic sensors are fixedly mounted on both sides of the bottom of the robot, located on both sides of the robot's central axis. The ultrasonic sensors are generally installed at the front of the robot's bottom to cooperate with the inertial sensor to detect in a timely manner whether the specific medium area exists in front of the robot. This front refers to the robot's walking direction, and the robot's central axis is parallel to the walking direction. Preferably, one ultrasonic sensor is installed on the left and one on the right side of the robot's central axis, and the vertical distance between each ultrasonic sensor and the central axis is between 2 cm and 3 cm.

[0022] It should be noted that before executing the robot relocalization method, the robot remains within a specific medium area. This specific medium area is a closed region where the robot may slip, such as a carpet or other surface layer. Specifically, the robot can start from a preset starting point and walk within this specific medium area according to a preset planned path. During the walking process, the robot does not calculate its own pose information (including position coordinates and angle information) and does not build a map in real time. The robot can change its walking direction at predetermined time intervals. This allows the robot to adjust the preset planned path before it accumulates a sufficiently large offset error due to slippage within the specific medium area. This prevents the robot from deviating too far from the original preset planned path while still providing relatively comprehensive coverage of the specific medium area. At this point, the robot is still within the specific medium area, but it has not calculated and obtained the relevant pose information of its current position point. The robot has not updated the global map and therefore cannot obtain real-time positioning information from the global map, necessitating the execution of the robot relocalization method. In some embodiments, the robot begins to execute the robot relocation method when the robot records that its walking time in a specific medium area has reached a predetermined end time, and it is determined that the robot has traversed the specific medium area.

[0023] The robot relocation method includes: Step 1: The robot walks within the specified medium area to the boundary line of the specified medium area, and then adjusts the two ultrasonic sensors to be positioned on either side of the boundary line of the specified medium area. When starting Step 1, the robot can be already on the boundary line of the specified medium area, or it can be in the vicinity of the center point of the specified medium area (which can be a local area 30 cm away from the center point). Generally, as the robot moves along a pre-planned path (which can be the zigzag path often used by robotic vacuum cleaners) within a specific area, it detects the boundary line of the specific area by combining the intensity of the ultrasonic reflected signals received by the ultrasonic sensors and the angle information measured by the inertial sensors. Then, on or near the boundary line (which can be a distance from the boundary line but within the detection range of the ultrasonic sensors), the robot begins to adjust the two ultrasonic sensors to be positioned on either side of the boundary line. In some implementations, after the robot adjusts the two ultrasonic sensors to be positioned on either side of the boundary line, the robot's current position is located on the boundary line. It should be noted that the robot's current position is the center point of the robot's body. The method of adjusting the two ultrasonic sensors to be positioned on either side of the boundary line can be that the robot rotates its body and changes its direction of travel until each ultrasonic sensor detects the corresponding ground medium type information.

[0024] Step 2: The robot walks while maintaining the two ultrasonic sensors positioned on either side of the boundary line of the specific medium region. The robot moves along the boundary line until it reaches a corner. The pose information of this corner is then used to update the robot's current pose, completing the robot's relocalization. It should be noted that the pose information of each boundary line forming the specific medium region is pre-stored in the robot's memory. This is achieved by marking the corresponding grids on the global map and recording the pose information before the robot enters the specific medium region. A corner is the endpoint of a boundary line forming the specific medium region, i.e., the common endpoint of two adjacent boundary lines; its pose information is also pre-stored in the robot's memory. In this embodiment, whether the robot has reached a corner can be determined by the change in rotation angle over a certain period of time, the relationship between the rotation angle and the pre-stored grid positions, the relationship between the starting point of the robot's movement along the boundary line of the specific medium region and the position of the first corner reached, or a combination of these factors for a comprehensive judgment, etc. Thus, without real-time mapping of new grid information or real-time calculation of robot pose information, the robot's current position can be repositioned to the pre-recorded position of this corner point within the robot.

[0025] Specifically, the two ultrasonic sensors, positioned on either side of the boundary line of the specific medium area, are located on the left and right sides of the robot's central axis. When the specific medium area is polygonal and the two ultrasonic sensors are configured to be mounted on either side of the robot's central axis, in order to maintain the two ultrasonic sensors positioned on either side of the boundary line of the specific medium area, the robot will rotate its body once or multiple times during movement. During this process, the robot's body (including the drive wheels and ultrasonic sensors) inevitably repeatedly enters and exits the specific medium area. The robot's movement trajectory forms a trajectory line intersecting with the boundary line of the specific medium area. In this implementation, the robot walks along the boundary line of the specific medium area. When the robot is a vacuum cleaner, it can perform staggered cleaning of the specific medium area, moving in a preset clockwise direction within the specific medium area to achieve edge-to-edge movement around the center of the specific medium area in a fixed direction.

[0026] In one embodiment, the two ultrasonic sensors are symmetrically mounted on the left and right sides of the robot's central axis in some implementations, making it easier to control the robot to walk along the boundary line of a specific medium area. The robot's left and right drive wheels are preferably positioned on either side of the boundary line of the specific medium area. When the shape of the specific medium area is rectangular, if the robot walks while maintaining the two ultrasonic sensors positioned on either side of the boundary line, the robot's central axis is parallel to the boundary line of the specific medium area it traverses. The robot is then controlled to walk along the boundary line of the specific medium area in this manner until it determines, based on the angle information detected by the robot, that it has reached the corner point, which corresponds to the vertex of the rectangle. Since the robot walks on or near the boundary line, and the displacement information measured by the encoder or odometer in the inertial sensor within the specific medium area exhibits slippage error, the robot generates walking errors at the corresponding boundary segments, making positioning difficult. It is not suitable to use boundary points other than the corner points as references for repositioning, as the robot needs to rotate at a specific angle in its walking direction at the corner point. A suitable reference angle for repositioning can be a reference angle set within a pre-defined range of allowable slippage error.

[0027] It should be noted that the pose information of the corner points is pre-stored in the robot's memory. Similarly, the global map is pre-stored in the robot's memory. This global map is created before the robot enters the specific medium area by using its onboard sensors (e.g., accelerometers, gyroscopes, ultrasonic rangefinders, etc.) to search the movement area of ​​each room, sensing the position, shape, and size of each room, as well as the position, shape, and size of any obstacles encountered, and based on this, drawing a global map containing environmental boundary information.

[0028] As one embodiment, in step 1, the method of adjusting the two ultrasonic sensors to be positioned on either side of the boundary line of a specific medium region includes: When the robot walks to the boundary line of a specific medium area, it rotates its body to adjust its walking direction. The robot can rotate its body in place and its body can cover the boundary line until the intensity of the ultrasonic reflected signal received by the first ultrasonic sensor is not within the preset intensity threshold range, the intensity of the ultrasonic reflected signal received by the second ultrasonic sensor is within the preset intensity threshold range, and the attitude angle measured by the inertial sensor is less than or equal to a preset angle threshold. Then, the robot does not detect the specific medium area on the side corresponding to the first ultrasonic sensor, and the robot detects the specific medium area on the side corresponding to the second ultrasonic sensor. The first ultrasonic sensor and the second ultrasonic sensor are located on opposite sides of the boundary line of the specific medium area, thus determining the state of the robot being located on opposite sides of the boundary line of the specific medium area. The preset angle threshold is determined by the inverse trigonometric function result of the maximum allowable height that the robot can cross over the obstacle. The first ultrasonic sensor and the second ultrasonic sensor are fixedly mounted on both sides of the robot's central axis. There is a boundary line of the specific medium area between the first ultrasonic sensor and the second ultrasonic sensor. Preferably, when the first ultrasonic sensor and the second ultrasonic sensor are symmetrically arranged on the left and right sides of the robot's central axis, the first ultrasonic sensor and the second ultrasonic sensor can be symmetrically arranged about the boundary line of the specific medium area along which the robot is moving.

[0029] During the execution of the robot relocalization method, the robot controls each ultrasonic sensor to emit ultrasonic waves and receive reflected ultrasonic signals, while simultaneously controlling inertial sensors to measure the robot's attitude angles. Corresponding to step 1, before the robot begins walking along the boundary line of a specific medium region or during the process of the robot rotating its body to adjust its walking direction, the following detection results are included: When the intensity of the ultrasonic reflected signal received by the ultrasonic sensor is not within a preset intensity threshold range, the robot has not detected a specific medium area; specifically, the surface of the area in front of the robot does not contain a specific medium, and the robot is not in a state of crossing the first target obstacle. It should be noted that the ultrasonic sensor provides ultrasonic signals with different intensities based on the surface density of different cleaning objects. The value within the preset intensity threshold range is related to the type of medium on the surface of the specific medium area. It should be noted that the state of the robot crossing the first target obstacle is relative to a horizontal plane, with the robot's body tilted on the surface of the first target obstacle; the state of the robot not crossing the first target obstacle is relative to a horizontal plane, with the robot horizontally positioned on the surface of the first target obstacle, or the robot not in contact with the first target obstacle. In this embodiment, the horizontal plane is equivalent to a horizontal ground surface. The ultrasonic sensor is either a first ultrasonic sensor or a second ultrasonic sensor. Therefore, when the intensity of the ultrasonic reflected signal received by the first ultrasonic sensor is not within the preset intensity threshold range, it is determined that the robot has not detected a specific medium area on the side corresponding to the first ultrasonic sensor; specifically, the robot has not detected a specific medium area in front of the side corresponding to the first ultrasonic sensor.

[0030] In practical applications, the intensity of the ultrasonic signals fed back by carpets and obstacles climbed by robots is lower than that fed back by the floor. Based on this, an angle threshold or angle threshold range can be set. Using the angle threshold range corresponding to the attitude angle measured by the inertial sensor, the robot can distinguish whether the walking environment is located in a specific medium area or a raised obstacle that it can climb. Specifically, the first target obstacle protrudes from the horizontal plane, and its height is greater than the maximum allowable height for the robot to cross. When the robot is crossing the first target obstacle, there is a risk of slipping or spinning on its surface. Therefore, the robot must break free from the first target obstacle to avoid slipping or spinning.

[0031] When the intensity of the ultrasonic reflected signal received by the ultrasonic sensor is within a preset intensity threshold range, and the attitude angle measured by the inertial sensor is within a first preset angle threshold range, the robot detects the presence of the specific medium (such as a carpet) on the surface in front of it. The robot detects the specific medium area, which can be a localized region of the specific medium area. Simultaneously, the robot is not in a state of crossing obstacles, including not crossing the first target obstacle. This allows for the detection of the specific medium area and the first target obstacle within a signal intensity range of the ultrasonic reflected signal (within the preset intensity threshold range), thus distinguishing between the specific medium area and the first target obstacle and avoiding misjudgment. In this embodiment, "not crossing obstacles" means that the robot is not in inclined contact with the surface of the obstacle; the robot can be horizontally positioned on the surface of the obstacle. The ultrasonic sensor is either a first ultrasonic sensor or a second ultrasonic sensor. Therefore, when the intensity of the ultrasonic reflected signal received by the second ultrasonic sensor is within the preset intensity threshold range, and the attitude angle measured by the inertial sensor is less than or equal to the preset angle threshold, it is determined that the robot has detected the specific medium area on the side corresponding to the second ultrasonic sensor; specifically, the robot has detected the specific medium area in front of the side corresponding to the second ultrasonic sensor.

[0032] In the above embodiments, when the intensity of the ultrasonic reflected signal received by the ultrasonic sensor is not within a preset intensity threshold range, and the attitude angle measured by the inertial sensor is less than or equal to a preset angle threshold, the robot is not in a state of crossing obstacles. The attitude angle measured by the inertial sensor may be equal to 0, causing the robot to be horizontally positioned on the surface of the obstacle or not in contact with the obstacle protruding from the horizontal ground. Here, "not in a state of crossing obstacles" means that the robot is horizontally positioned on the surface of the obstacle relative to the horizontal plane, or the robot is not in contact with the obstacle. The obstacle includes a first target obstacle, a second target obstacle, and other obstacles protruding from the horizontal ground at other heights. In this embodiment, the horizontal plane is equivalent to the horizontal ground.

[0033] It should be noted that the first preset angle threshold range is an angle range less than or equal to the preset angle threshold. The preset angle threshold is determined by the inverse trigonometric function result of the maximum allowable height that the robot can cross over obstacles. The specific calculation method is conventional trigonometric geometry calculation. According to the definitions of pitch angle and roll angle, there can be various conversion methods. Among them, the preset angle threshold and the maximum allowable height can be positively correlated. The specifics will not be elaborated here. When the attitude angle measured by the inertial sensor is the pitch angle, the preset angle threshold is the pitch angle converted from the maximum allowable height through the inverse trigonometric function; when the attitude angle measured by the inertial sensor is the roll angle, the preset angle threshold is the roll angle converted from the maximum allowable height through the inverse trigonometric function. The result of the inverse trigonometric function calculation only needs to retain a certain degree of accuracy. Therefore, in this embodiment, the preset angle threshold is configured as a value within a pre-set error order of magnitude. The pre-set error order of magnitude is preferably 0.1, so that the preset angle threshold is retained to the order of magnitude of 0.1. When the preset angle threshold calculated using the aforementioned inverse trigonometric function has multiple decimal places, the preset angle threshold, within an allowable error range of 0.1 on the order of magnitude, is used to obtain a single value by retaining one decimal place, which serves as the unique angle value. This is to meet the navigation accuracy requirements of the inertial sensor.

[0034] It is worth noting that in this embodiment, the acceleration information or the angle transformation result of the acceleration information measured by the inertial sensor is not further accumulated into an integral value, and the robot does not assist in building a global map in the specific medium area, so as to reduce the error caused by robot slippage.

[0035] It should be noted that the specific medium is carpet, and the specific medium area is the area covered by the carpet. Each closed area that makes up the specific medium area can be regarded as a carpet block, and the grid corresponding to the points on the edge of the carpet has been marked in the global map. Each closed area that makes up the specific medium area can be a rectangular partition covering the carpet, or it can be carpet of other shapes. Here, the shape refers to the shape of the horizontal plane of the relevant area. When the specific medium area is covered in an indoor environment, the shape of each closed area that makes up the specific medium area is associated with the planar shape of the room it actually covers. The grid corresponding to the boundary point of each closed area is marked in the global map. Even if the boundary points obtained by the robot are discrete points, they can form a closed area (equivalent to a closed area) within the allowable error range. In some embodiments, the carpet area consists of multiple carpet blocks, with two carpet blocks isolated from each other and located in different room areas. Each carpet block is marked as a closed grid area on the global map. The floor of a room area is covered by one carpet block, and the shape of the carpet block is the same as the shape of the floor of the room area (the shape of the area enclosed by the boundary of the room). For example, when a room area is composed of a connected large rectangle and a small rectangle, the shape of a carpet block is also the shape of the combined shape of a connected large rectangle and a small rectangle. The boundary points that form the boundary line of the specific medium area are points on the edge line of the specific medium area, which can also be understood as points on the outline of the planar area covered by the specific medium. These points can be derived from the point cloud information received by the ultrasonic sensor, specifically calculated from the distance measurement information fed back by the ultrasonic reflection signal from the surface of the specific medium area, and are data recorded in the robot's memory before executing the robot relocalization method.

[0036] As one embodiment, in step 1, the method for determining the boundary line of the specific medium area where the robot has walked includes: during the robot's movement within the specific medium area, when the intensity of the ultrasonic reflected signal received by the ultrasonic sensor is not within a preset intensity threshold range, the robot determines that it has reached the boundary line of the specific medium area; wherein, the preset intensity threshold range is used to represent the signal intensity range of the ultrasonic reflected signal fed back from the specific medium area. The ultrasonic sensor is a first ultrasonic sensor or a second ultrasonic sensor, that is, during the robot's movement within the specific medium area, as long as the intensity of the ultrasonic reflected signal received by the ultrasonic sensor on one side (left or right) of the robot is not within the preset intensity threshold range, it can be determined that the robot has reached the boundary line of the specific medium area.

[0037] In some embodiments, the robot walks within a specific medium area according to a pre-planned path. The robot controls ultrasonic sensors to emit ultrasonic waves and receive reflected ultrasonic signals. Excluding interference from the signal strength of reflected ultrasonic signals from obstacles at a specific height (where the attitude angle measured by the inertial sensor is less than or equal to a preset angle threshold), if the intensity of the reflected ultrasonic signal received by the ultrasonic sensor is within a preset intensity threshold range, it is determined that the robot has detected a specific medium, such as a carpet, on the surface in front of it; that is, the robot has detected the specific medium area. However, if, during the robot's movement within the specific medium area, the intensity of the reflected ultrasonic signal received by one ultrasonic sensor is not within the preset intensity threshold range, the robot has detected the specific medium area in front of it. The surface of the domain lacks a specific medium. Since the robot walks within the area of ​​the specific medium, when the robot detects the absence of a specific medium on the surface of the area in front of it, the detection range of the ultrasonic sensor is outside the specific medium area. The ultrasonic sensor may be located outside the specific medium area. In this embodiment, the robot detects the boundary line of the specific medium area and determines that it has reached the boundary line. Then, the robot adjusts its walking direction, i.e., adjusts its walking angle, moving towards the interior of the specific medium area to prevent the robot from completely leaving the boundary line. Part of the robot can be allowed to protrude outside the specific medium area, but the walking direction needs to be adjusted to guide the robot along the boundary line. In summary, without calculating the robot's pose or using global map positioning, the robot controls its contact with the boundary line of the specific medium area by using the signal strength information of the ground medium sensed by the ultrasonic sensor. This avoids the slippage and misjudgment caused by the inertial sensor within the specific medium area and ensures that the robot searches for the pre-saved boundary line within the specific medium area for subsequent repositioning.

[0038] It should be noted that the inertial sensor includes a six-axis gyroscope. A three-axis gyroscope senses omnidirectional dynamic information in Roll (left / right tilt), Pitch (backward / forward tilt), and Yaw (left / right sway). A six-axis gyroscope refers to the combination of a three-axis accelerometer (which senses acceleration along the XYZ axes in three-dimensional space) and a three-axis gyroscope, forming an inertial navigation system. This system is an autonomous navigation system that does not rely on external information and does not radiate energy externally. The six-axis gyroscope can measure the robot's pose information, primarily its own pose, which includes position and orientation.

[0039] In the foregoing embodiments, the attitude angles measured by the inertial sensor are pitch angles or roll angles to obtain the robot's angle information on the obstacle. Preferably, the robot's angle information on the obstacle can include the changes in attitude angles generated during the robot's traversal of the obstacle from an initial value, specifically changes within a specific sampling time period. The sampling time period is related to the robot's traversal capability and also to the rotational speed of the drive wheels. In the foregoing embodiments, the pitch angle represents the angle between the contact surface between the robot and the obstacle and the horizontal plane, which is also equivalent to the angle between the robot's walking direction and the horizontal plane; the roll angle represents the angle between the robot's wheel axis and the horizontal plane; the robot's wheel axis is the axis of the drive wheels mounted on both sides of the robot's body, that is, the line connecting the centers of the drive wheels mounted on both sides.

[0040] As one example, such as Figure 1 As shown, the robot relocalization method based on a specific medium region includes the following steps: Step D101: The robot walks within the specific medium area to the boundary line of the specific medium area, and then adjusts the two ultrasonic sensors to be positioned on either side of the boundary line of the specific medium area; then the robot executes step D102. Related implementation methods can be found in the method described in step 1 above.

[0041] In some embodiments of step D101, before the robot adjusts the two ultrasonic sensors (the first and second ultrasonic sensors described in the aforementioned embodiments) to be positioned on either side of the boundary line of the specific medium region, the robot walks along the target direction within the specific medium region to the target boundary line. That is, the robot walks along the target direction from its position within the specific medium region when it begins executing the robot relocation method. The target direction is defined as falling within the angle formed by the lines connecting the preset starting point and the two endpoints of the target boundary line. The target boundary line is any boundary line that encloses the specific medium region. Its related pose information is pre-stored in the robot for easy retrieval and corresponds to the direction of the target direction. The robot's memory stores a mapping relationship between the target boundary line and the target direction, i.e., a correspondence between one target direction and one target boundary line, with one target direction pointing to the corresponding target boundary line.

[0042] Specifically, the preset walking starting point is the starting position point for the robot to walk within a specific medium area before executing the robot relocation method; the preset walking starting point is a pre-set fixed position point; in an indoor environment, since the shape of the specific medium area is adapted to the plan shape of the room it actually covers, the boundary line of the specific medium area can coincide with the boundary line of a room to cover the floor area of ​​that room. Therefore, each boundary line enclosing the specific medium area is fixed, and the orientation information of each boundary line enclosing the specific medium area relative to the preset walking starting point is pre-obtained fixed information, including the angle information and distance information of the boundary points (including endpoints) on each boundary line enclosing the specific medium area relative to the preset walking starting point.

[0043] Preferably, the preset walking starting point is set within a specific medium area. The robot walking within the specific medium area according to a preset planned path can also be described as the robot walking along a preset planned path within the specific medium area. Before executing the robot relocalization method, to ensure that the robot does not easily leave the specific medium area and that there is a sufficiently open walking area within the specific medium area, the robot sets the preset walking starting point to the center point of the specific medium area; then, the robot is controlled to start walking from the center point of the specific medium area according to the preset planned path. The center point of the specific medium area can refer to the exact center point of a regular shape. When the shape of the specific medium area is irregular, the grid coordinates corresponding to the center point of the specific medium area are calculated through the boundary points on the boundary line of the specific medium area.

[0044] In some embodiments, the target direction is the walking direction when the robot begins to execute the robot relocation method so as to enable the robot to walk in a straight line to the target boundary line; or, the target direction is a direction at a preset target angle to the walking direction when the robot begins to execute the robot relocation method so that the robot can avoid obstacles in a specific medium area by adjusting the preset target angle and then walking in a straight line to the target boundary line, wherein the preset target angle is related to the obstacles distributed in the walking direction when the robot begins to execute the robot relocation method.

[0045] In step D101, before adjusting the two ultrasonic sensors to be positioned on either side of the boundary line of the specific medium area, the robot uses an inertial sensor to measure the angle formed by the robot's latest walking direction relative to the line connecting one endpoint of the target boundary line and the preset walking starting point in a preset clockwise direction. This endpoint connects to the other endpoint on the target boundary line in a preset clockwise direction. When the target boundary line is a line segment, above the preset walking starting point, the endpoint extends counterclockwise from the left to the right, or clockwise from the right to the left. When the target boundary line is a line segment, below the preset walking starting point, the endpoint extends clockwise from the left to the right, or counterclockwise from the right to the left.

[0046] When the robot detects that the angle (the angle formed by the line connecting one endpoint of the target boundary line and the preset starting point of the walking direction in a preset clockwise direction relative to the robot's latest walking direction) is less than or equal to the angle formed by the lines connecting the two endpoints of the preset starting point of the walking direction and the target boundary line, it determines that the robot is walking along the target direction within a specific medium area. This allows the robot to walk along the target direction until it detects the boundary line (in the aforementioned embodiment, when the intensity of the ultrasonic reflection signal received by the ultrasonic sensor is not within a preset intensity threshold range, the robot determines that it has walked to the boundary line of the specific medium area). Then, the robot determines that its current boundary line (the boundary line reached along the target direction) is the target boundary line based on the pre-saved mapping relationship between the target boundary line and the target direction.

[0047] When the planar shape of a specific medium area is a square, and the preset walking starting point is the center point of the specific medium area, the line connecting the left endpoint of the target boundary line and the preset walking starting point is located on a diagonal of the square. Furthermore, whenever the angle formed by the robot's latest walking direction relative to the line connecting the left endpoint of the target boundary line and the preset walking starting point in the clockwise direction increases by 90 degrees, the target boundary line changes once, becoming a boundary line perpendicular to the right endpoint of the original target boundary line. Whenever the angle formed by the robot's latest walking direction relative to the line connecting the left endpoint of the target boundary line and the preset walking starting point in the clockwise direction is less than 90 degrees, the target boundary line is determined.

[0048] In step D102, the robot sets its position when it begins to maintain the state where the two ultrasonic sensors are positioned on either side of the boundary line of the specific medium region as the relocation starting point, and determines that the robot has begun to maintain the state where the two ultrasonic sensors are positioned on either side of the boundary line of the specific medium region. Then, the robot executes step D103 so that the robot can walk along the boundary line of the specific medium region, that is, walk along the target boundary line disclosed in some embodiments of step D101. When the robot's current position is the robot's body center point, especially when the two ultrasonic sensors are symmetrically positioned on either side of the boundary line of the specific medium region, the robot's body center point moves along the target boundary line disclosed in some embodiments of step D101.

[0049] Step D103: While maintaining the two ultrasonic sensors positioned on either side of the boundary line of the specific medium area, the robot begins to move clockwise from the repositioning starting point, ensuring it travels along the boundary line of the specific medium area. When the robot's current position is its center point, especially when the two ultrasonic sensors are symmetrically positioned on either side of the boundary line, the trajectory of the robot's center point is parallel to the boundary line of the specific medium area. Simultaneously, the robot uses inertial sensors to detect angle changes. Specifically, the robot uses a gyroscope to detect the angle changes generated from the repositioning starting point. These angle changes represent the robot's heading angle, indicating a change in its direction of travel, specifically a change in its direction of travel on the horizontal plane of the specific medium area. Step D104 is then executed to simultaneously determine the magnitude of the angle change.

[0050] Step D104: Determine whether the angle change detected by the robot from the repositioning starting point reaches the reference angle. If yes, proceed to step D106; otherwise, proceed to step D105. Preferably, the reference angle is within the allowable angle range for the robot's slippage error within the specific medium area, allowing the robot to maintain its movement along the boundary line of the specific medium area by rotating at the corner point using the reference angle. In this embodiment, the robot's adjustment of its walking direction to maintain the state where the two ultrasonic sensors are positioned on opposite sides of the boundary line of the specific medium area can, to some extent, correct the slippage error that exists when the gyroscope detects the angle.

[0051] It should be noted that within a short time interval, the accumulated slippage and drift error of the robot is not very large and there is no need to reposition. After all, frequent repositioning will reduce the robot's walking efficiency. Therefore, in order to achieve the best positioning effect for the robot, when it is determined in step D104 that the angular change detected by the robot from the repositioning starting point reaches the reference angle, step D106 is executed to update the pose information of the robot's current position.

[0052] Preferably, the reference angle is the angle between the target boundary line and its boundary line connected in a preset clockwise direction, and the corner point is the common endpoint of the target boundary line and its boundary line connected in a preset clockwise direction; wherein, the planar shape of the specific medium region is a polygon, the corner point is a vertex of the polygon, and the boundary line is an edge of the polygon, such that each boundary line of the specific medium region is a straight line segment. The grid corresponding to the boundary points of the specific medium region is marked in the global map. The boundary points of the specific medium region include corner points. When the planar shape of the specific medium region is a polygon, the corner points of the specific medium region are vertices of the specific medium region, and the boundary lines of the specific medium region are the edges that enclose the polygon. The specific medium region is equivalent to a closed figure composed of multiple boundary line segments connected end to end in sequence, corresponding to a closed region. The polygon can be divided into regular polygons and non-regular polygons, convex polygons and concave polygons, and is preferably a rectangle. Due to the influence of walking errors, if the reference angle is set too small, it is difficult to find a suitable repositioning position; if the reference angle is set too large, the accuracy of the found object is relatively low. Therefore, in this embodiment, the reference angle can be set to allow the robot to walk to a corner position, such as the endpoint of a line segment or the common endpoint of two boundary lines. Since these types of points are pre-saved in the robot's memory, and the boundary lines where they are located are known in step D101, optimal repositioning matching effect can be achieved. This embodiment uses corner points for repositioning to improve the robot's positioning accuracy in specific medium areas where slippage is likely.

[0053] Step D106: The robot walks to a corner point, and then uses the pose information of that corner point to update the robot's current pose information. The grid coordinates currently stored by the robot to mark its current position are replaced with the grid coordinates already stored in the corresponding grid of the corner point. This enables the robot to reposition itself and regain its pose information within the specific medium area. It should be noted that the corner point is the common endpoint of the two boundary lines of the specific medium area. It is a position point where the robot maintains its movement along the boundary lines of the specific medium area by rotating the reference angle. That is, when the robot walks to or near the corner point while maintaining the state where the two ultrasonic sensors are positioned on either side of the boundary lines of the specific medium area, in order to maintain its movement along the boundary lines of the specific medium area (continuing to maintain the state where the two ultrasonic sensors are positioned on either side of the boundary lines of the specific medium area), the robot needs to rotate the reference angle in the preset clockwise direction. This is an adjustment of the reference angle in the robot's walking direction. The boundary lines forming the specific medium area are pre-marked in the corresponding grids of the global map, which is pre-stored in the robot's memory.

[0054] Then, the robot does not continue to maintain the state where the two ultrasonic sensors are on opposite sides of the boundary line of the specific medium area, so that the robot does not walk along the boundary line of the specific medium area; if the robot subsequently enters a new specific medium area, the angular change detected by the robot from the repositioning starting point disclosed in the aforementioned steps D103 and D104 is cleared to avoid misjudgment.

[0055] Specifically, when the robot detects an angle change reaching the reference angle from the repositioning starting point, it determines that the robot has walked to the corner point and rotated through the reference angle in a preset clockwise direction at the corner point. Then, the robot uses the pose information of the corner point to update the robot's current pose information. The repositioning starting point is the position point where the robot begins to maintain the state where the two ultrasonic sensors are located on opposite sides of the boundary line of the specific medium region. The corner point and the repositioning starting point are located on the same boundary line of the specific medium region, which is located between the two ultrasonic sensors. Among the two ultrasonic sensors, one ultrasonic sensor is located above the specific medium region, and the other ultrasonic sensor is located above an area outside the specific medium region.

[0056] In step D105, while keeping the two ultrasonic sensors on either side of the boundary line of the specific medium area, the robot continues to walk in a preset clockwise direction, so that the robot continues to walk along the boundary line of the specific medium area in a preset clockwise direction, and then returns to step D104, thus realizing the execution of step D104 while walking along the boundary line of the specific medium area.

[0057] It should be noted that the preset clockwise direction is either clockwise or counterclockwise. When the robot walks along the boundary line of a specific medium area, walking below the preset starting point of the specific medium area is manifested as walking clockwise towards the lower left boundary line of the specific medium area, or walking below the preset starting point of the specific medium area is manifested as walking counterclockwise towards the lower right boundary line of the specific medium area, or walking above the preset starting point of the specific medium area is manifested as walking counterclockwise towards the upper left boundary line of the specific medium area, or walking above the preset starting point of the specific medium area is manifested as walking clockwise towards the upper right boundary line of the specific medium area.

[0058] Preferably, the specific medium region is a rectangular region whose surface is covered with a specific medium. The corner point is the vertex of the rectangular region, and the reference angle is 90 degrees. This allows the robot to rotate a right angle in a preset clockwise direction, and then update the robot's current pose information using the pose information of the vertex of that right angle. Each side of the rectangular region is a boundary line, and the rectangular region is enclosed by four boundary lines. The pose information of the vertex of the right angle includes the coordinates and angle information of that vertex, both of which are pre-saved pose information for subsequent repositioning operations. Corresponding to an indoor environment, the robot's walking environment covers the floor of the indoor environment, where the walls are perpendicular to the floor. If the specific medium region covers the floor of the indoor environment, then all turns in the robot's trajectory along the specific medium region are right angles, and the angles between the intersecting boundary lines of the specific medium region are also right angles.

[0059] In summary, when the robot navigates along the boundary line of a specific medium area, slippage errors occur. Therefore, it does not search for a grid path in the global map. Instead, it adjusts its walking direction according to step 1 or step D101 of the aforementioned embodiment, maintaining the two ultrasonic sensors on either side of the boundary line of the specific medium area. It then walks along the boundary line, point by point, until it reaches the corner point mentioned in step D106. That is, the robot detects an angle change from the repositioning starting point that reaches the reference angle. When the robot is cleaning a carpet, it maintains the ultrasonic sensors on both sides of the boundary line, ensuring stable movement along the boundary line. Based on this, it searches for a corner point in the specific medium area by measuring the angle change, thus repositioning the robot's current position to the location recorded on the map for that corner point. This improves the accuracy of the repositioning location information while reducing computational load. It avoids mapping errors caused by the robot's drive wheels slipping on the carpet surface and facilitates subsequent path planning using the accurately repositioned location. The beneficial effects of the present invention include: by using the path of the robot walking along the edge of the specific medium area as a reference, the positional deviation caused by excessive accumulation of robot walking errors can be corrected, and repositioning can be achieved, thereby improving the accuracy of robot positioning and walking efficiency during subsequent navigation.

[0060] Based on the aforementioned embodiments, when the robot walks within the specific medium area, the robot controls the ultrasonic sensor to emit ultrasonic waves and receive reflected ultrasonic signals, and controls the inertial sensor to measure the robot's attitude angles, including the pitch angle or roll angle used to detect the specific medium area in conjunction with the ultrasonic sensor, and the heading angle used to detect the change in angle when proceeding to step 2 or step D103, but stops marking the grid on the global map. After the robot updates its current pose information using the pose information of the corner points, the robot walks to an area outside the specific medium area. At the same time, the robot acquires its pose information and marks the corresponding grid on the global map for map building operations. The surface covering medium of the area outside the specific medium area is different from the specific medium covering the surface of the specific medium area. The specific medium area is a closed area that causes the robot to slip, such as a carpet area, while the area outside the specific medium area is a closed area that is less likely to cause the robot to slip.

[0061] Based on the foregoing embodiments, the present invention also discloses a robot equipped with at least one inertial sensor, at least two ultrasonic sensors, and at least one processor. At least two ultrasonic sensors are fixedly mounted on both sides of the robot's bottom, located on either side of the robot's central axis, which is parallel to the walking direction. When the processor executes the computer program, it implements the aforementioned robot repositioning method. After cleaning a carpet, the robot walks along the boundary line of a specific medium area by keeping the ultrasonic sensors on its left and right sides positioned on either side. Based on this boundary line, the robot searches for a corner point within the specific medium area using angle changes, thereby repositioning the robot's current position to the location recorded on the map for that corner point. This improves the accuracy of the repositioning calculation while reducing computational load; it avoids mapping errors caused by the robot's drive wheels slipping on the carpet surface and facilitates subsequent path planning using the accurately repositioned location.

[0062] Inertial sensors are housed inside the robot and include an encoder, accelerometer, and gyroscope. The accelerometer is a sensor that senses axial acceleration and converts it into a usable output signal; the gyroscope is a sensor that senses the robot's angular velocity in a specific medium area. The encoder, accelerometer, and gyroscope together form an inertial navigation system, enabling autonomous navigation that does not rely on external information or radiate energy externally. In this embodiment, at least two ultrasonic sensors are fixedly mounted on both sides of the robot's bottom, located on either side of the robot's central axis. The ultrasonic sensors are generally installed at the front of the robot's bottom to cooperate with the inertial sensors in timely detecting the presence of the specific medium area in front of the robot. This "front" points to the robot's walking direction, and the robot's central axis is parallel to the walking direction. Preferably, one ultrasonic sensor is installed on each of the left and right sides of the robot's central axis, with each ultrasonic sensor's vertical distance from the central axis between 2 and 3 centimeters. The inertial sensors include a six-axis gyroscope. It's important to note that a three-axis gyroscope senses omnidirectional dynamic information in Roll (tilt left / right), Pitch (tilt forward / backward), and Yaw (sway left / right). A six-axis gyroscope, on the other hand, refers to a combination of a three-axis accelerometer (which senses acceleration along the XYZ axes in three-dimensional space) and a three-axis gyroscope, forming an inertial navigation system. This system is an autonomous navigation system that does not rely on external information or radiate energy externally. The six-axis gyroscope can measure the robot's pose information, primarily its own pose, which includes position and orientation.

[0063] In this embodiment, the robot may be a cleaning robot. The cleaning robot includes a main body, a sensing system, a control system, a drive system, a cleaning system, and an energy system. The main body of the cleaning robot includes a forward portion and a rearward portion, and has an approximately circular shape (both front and rear are circular). It may also have other shapes, including but not limited to an approximately D-shaped shape with a circular front and rear, or a rectangular or square shape with a circular front and rear. In some embodiments, collision sensors and proximity sensors are disposed on the forward portion of the robot's main body, cliff sensors are disposed on the lower part of the robot's main body, and a controller, magnetometer, accelerometer, gyroscope, and odograph (ODO) installed inside the drive wheels, and drop sensors are installed in slots connecting the left and right drive wheels to the chassis of the robot body. These sensing devices provide the processor with various position and motion state information of the machine. The processor can manipulate the robot to traverse different types of terrain based on drive commands with distance and angle information (e.g., x, y, and z components). The processor includes a drive wheel module that can simultaneously control the left and right drive wheels. For more precise control of the robot's movement, preferably, the drive wheel module includes a left drive wheel module and a right drive wheel module, symmetrically arranged along a transverse axis defined by the robot body. To enable the robot to move more stably or with greater mobility on the ground, the robot may include one or more driven wheels, including but not limited to omnidirectional wheels for changing direction. The drive wheel module includes drive wheels, drive motors, and control circuitry for controlling the drive motors. The drive wheel module may also be connected to circuitry for measuring drive current, an odometer, and a gyroscope.

[0064] This invention also discloses a chip storing a program that, when executed by the chip, implements the robot relocalization method disclosed in the foregoing embodiments. When this chip is mounted on the robot described in the foregoing embodiments, it controls the robot to walk with its left and right ultrasonic sensors positioned on either side of the boundary line of a specific medium area. By searching for a corner point within the specific medium area through angle changes, the robot's current position is relocated to the position of this corner point recorded on the map. This improves the accuracy of the relocated position information while reducing computational load, facilitating the robot's subsequent path planning using the accurately relocated position.

[0065] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A robot relocalization method based on a specific medium region, characterized in that, This robot repositioning method is applicable to robots equipped with inertial sensors and ultrasonic sensors, wherein at least two ultrasonic sensors are fixedly mounted on both sides of the bottom of the robot, and are located on both sides of the robot's central axis, which is parallel to the direction of travel. Before implementing this robot relocation method, the robot travels within a specific medium area; The robot relocation method includes: Step 1: The robot walks to the boundary line of the specific medium area, and then adjusts the two ultrasonic sensors to be positioned on both sides of the boundary line of the specific medium area. Step 2: The robot walks while keeping the two ultrasonic sensors on either side of the boundary line of the specific medium area, so that the robot walks along the boundary line of the specific medium area until it reaches a corner. Then, the pose information of the corner is used to update the robot's current pose information to complete the robot's relocalization. The pose information of each boundary line that encloses the specific medium region is pre-stored in the robot's memory, and the corner points are the endpoints of the boundary lines that enclose the specific medium region. In step 1, the method of adjusting the two ultrasonic sensors to be positioned on either side of the boundary line of a specific medium region includes: When the robot walks to the boundary line of a specific medium area, the robot rotates its body to adjust its walking direction until the intensity of the ultrasonic reflected signal received by the first ultrasonic sensor is not within the preset intensity threshold range, the intensity of the ultrasonic reflected signal received by the second ultrasonic sensor is within the preset intensity threshold range, and the attitude angle measured by the inertial sensor is less than or equal to the preset angle threshold. Then, the robot does not detect the specific medium area on the side corresponding to the first ultrasonic sensor, and the robot detects the specific medium area on the side corresponding to the second ultrasonic sensor. Thus, it is determined that the robot is in a state where the two ultrasonic sensors are located on both sides of the boundary line of the specific medium area. The preset angle threshold is determined by the inverse trigonometric function of the maximum allowable height that the robot can cross over obstacles; the two ultrasonic sensors are a first ultrasonic sensor and a second ultrasonic sensor; the first ultrasonic sensor and the second ultrasonic sensor are fixedly mounted on both sides of the robot's central axis.

2. The robot relocation method according to claim 1, characterized in that, In step 1, the method for determining the boundary line of the specific medium region where the robot travels includes: When the intensity of the ultrasonic reflected signal received by the ultrasonic sensor is not within the preset intensity threshold range during the robot's movement within a specific medium area, the robot determines that it has walked to the boundary line of the specific medium area. The preset intensity threshold range is a pre-defined signal intensity threshold range used to represent the signal intensity range of the ultrasonic wave reflected signal fed back from the specific medium region. The ultrasonic sensor is either a first ultrasonic sensor or a second ultrasonic sensor.

3. The robot relocation method according to claim 1, characterized in that, In step 2, the robot walks while maintaining the two ultrasonic sensors positioned on either side of the boundary line of a specific medium region, allowing the robot to walk along the boundary line of the specific medium region until it reaches a corner point. The method of updating the robot's current pose information using the pose information of this corner point includes: Starting from the position where the robot initially maintains the state where the two ultrasonic sensors are positioned on either side of the boundary line of the specific medium area, the robot moves in a preset clockwise direction to move along the boundary line of the specific medium area, and uses inertial sensors to detect the change in angle. When the robot detects that the angle change has reached the reference angle, the robot moves to the corner point and then uses the pose information of the corner point to update the robot's current pose information, so as to enable the robot to regain its pose information in the specific medium area; wherein, the angle change is the change in the robot's heading angle, which is used to represent the change in the robot's walking direction. The corner point is the common endpoint of two boundary lines of a specific medium region, and is the position point where the robot maintains its movement along the boundary line of the specific medium region by rotating the reference angle. The preset clockwise direction is either clockwise or counterclockwise.

4. The robot relocation method according to claim 3, characterized in that, In step 1, before adjusting the two ultrasonic sensors to be positioned on either side of the boundary line of the specific medium area, the robot walks along the target direction to the target boundary line within the specific medium area; The target direction is within the angle formed by the lines connecting the two endpoints of the preset starting point and the target boundary line. Wherein, the target direction is the walking direction of the robot when it starts to execute the robot relocation method, or the direction that forms a preset target angle with the walking direction of the robot when it starts to execute the robot relocation method; the target boundary line is any boundary line that encloses a specific medium region; The preset walking starting point is the starting position point of the robot's movement within a specific medium area before the robot executes the robot relocation method; the preset walking starting point is a fixed position point that is set in advance; the orientation information of each boundary line enclosing the specific medium area relative to the preset walking starting point is fixed information obtained in advance.

5. The robot relocation method according to claim 4, characterized in that, The reference angle is the angle between the target boundary line and its boundary line connected in a preset clockwise direction, and the corner point is the common endpoint of the target boundary line and its boundary line connected in a preset clockwise direction. The planar shape of the specific medium region is a polygon, the corner points are vertices of the polygon, and the boundary lines are edges of the polygon, such that each boundary line of the specific medium region is a straight line segment.

6. The robot relocation method according to claim 5, characterized in that, The specific medium region is a rectangular region whose surface is covered with a specific medium. The corner point is the vertex of the rectangular region. The reference angle is 90 degrees, so that after the robot rotates a right angle in a preset clockwise direction, the pose information of the vertex of the right angle is used to update the robot's current pose information. The pose information of the vertex of the right angle includes the coordinate information and angle information of the vertex of the right angle; each side of the rectangular region is a boundary line, and the rectangular region is enclosed by four boundary lines.

7. The robot relocation method according to claim 3, characterized in that, When the robot detects that the angle change reaches the reference angle from the repositioning starting point, it determines that the robot has walked to the corner point and rotated through the reference angle in a preset clockwise direction at the corner point. Then the robot uses the pose information of the corner point to update the robot's current pose information. The repositioning starting point is the position of the robot when it begins to maintain the state where the two ultrasonic sensors are located on opposite sides of the boundary line of a specific medium area. The corner point and the repositioning starting point are located on the same boundary line of the specific medium region, which is located between the two ultrasonic sensors. Among the two ultrasonic sensors, one ultrasonic sensor is located above the specific medium region, and the other ultrasonic sensor is located above an area outside the specific medium region.

8. The robot relocation method according to claim 1, characterized in that, When the robot walks within the specified medium area, the robot controls the ultrasonic sensor to emit ultrasonic waves and receive ultrasonic reflection signals, and controls the inertial sensor to measure the robot's attitude angles, but stops marking the grid of the global map. After the robot updates its current pose information using the pose information of the corner points, the robot walks to an area outside the specific medium area. At the same time, the robot acquires its pose information and marks the corresponding grid in the global map. Wherein, the medium covering the surface of the area outside the specific medium area is different from the specific medium covering the surface of the specific medium area; The specific medium region is a closed area that causes the robot to slip.

9. A robot, characterized in that, The robot is equipped with at least one inertial sensor, at least two ultrasonic sensors and at least one processor. At least two ultrasonic sensors are fixedly mounted on both sides of the bottom of the robot and are located on both sides of the robot's central axis, which is parallel to the direction of travel. The processor is used to control the robot to perform the robot relocation method according to any one of claims 1 to 8.

10. A chip, wherein a program is stored on the chip, characterized in that, When the program is executed by the chip, it implements the robot relocation method as described in any one of claims 1 to 8.

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