Path Planning Method, Electronic Device and Storage Medium of Legged Robot

Abstract

The present application provides a path planning method, an electronic device, and a storage medium for a legged robot. The method includes: obtaining starting position information, target position information, and a global map of the surrounding environment, and planning a global path for the legged robot, where the global path includes at least one node; obtaining sensing information of the surrounding environment and constructing a local map that covers at least one node; constructing a local passable map based on the motion performance parameters of the legged robot and the local map; determining a local target node of the legged robot based on the global path and the current position of the legged robot; planning a local path for the legged robot based on the local map, the local passable map, the local target node, and the current position of the legged robot; and updating the local path until the legged robot reaches the target position. Through the path planning that combines global and local aspects, the legged robot in the present application can autonomously pass through or avoid complex terrains.

Description

Technical Field

[0001] The present application relates to the technical field of robotics, and particularly to a path planning method, an electronic device, and a storage medium for a legged robot. Background Art

[0002] With the development of Artificial Intelligence (AI) technology, robots are increasingly widely used in daily production and life. Common robots include robotic arms, Automatic Guided Vehicles (AGVs), automated forklifts, etc. With the growth of actual demands, in order to apply robots in a wider range, the application demands for legged robots, especially quadruped robots, are continuously increasing. Compared with wheeled robots, quadruped robots can traverse more complex road conditions and perform more complex tasks.

[0003] Compared with the application scenarios of wheeled robots, which are usually in small indoor environments, an important application scenario for legged robots is large outdoor environments, such as a range with a radius greater than 10 kilometers. For autonomous movement in large outdoor environments, legged robots mainly navigate based on topological maps. However, outdoor environments often include complex terrains such as steps, stairs, slopes, suspended obstacles, holes, gravel roads, etc., and topological maps cannot describe complex terrains. Thus, legged robots cannot autonomously pass through or avoid the above complex terrains. Summary of the Invention

[0004] In view of this, it is necessary to provide a path planning method, an electronic device, and a storage medium for a legged robot to solve the technical problem that legged robots cannot autonomously pass through or avoid complex terrains.

[0005] The present application provides a path planning method for a legged robot, the method comprising:

[0006] Obtaining starting position information, target position information, and a global map of the surrounding environment, and planning a global path for the legged robot, the global path including at least one node;

[0007] Obtaining sensing information of the surrounding environment, and constructing a local map, the local map covering at least one of the nodes;

[0008] Constructing a local passable map based on the motion performance parameters of the legged robot and the local map;

[0009] Determining a local target node of the legged robot based on the global path and the current position of the legged robot;

[0010] Plan a local path for the legged robot based on the local map, the locally passable map, the local target node, and the current position of the legged robot; and

[0011] Update the local path until the legged robot reaches the target position.

[0012] Optionally, the motion performance parameters of the legged robot include at least one of a height threshold for crossing a step, a roughness threshold for passing through the ground, a slope threshold for passing through a ramp, and a height threshold for passing through a suspended object.

[0013] Optionally, the local map is a local elevation map, and constructing the locally passable map based on the motion performance parameters of the legged robot and the local map includes:

[0014] Divide the projection plane of the local map into a plurality of cells;

[0015] Calculate the passability parameter of each cell, where the passability parameter t = 1 - d, and d is a danger value. where, α 1 、α 2 、α 3 and α 4 are preset coefficients, α 1 +α 2 +α 3 +α 4 = 1, s is the slope of the ramp, s crit is the slope threshold, r is the ground roughness, r crit is the ground roughness threshold, h is the step height, h crit is the step height threshold, f is the suspended height, f ceil is the upper limit value of the suspended height of the cell from the ground, f floor is the lower limit value of the suspended height of the cell from the ground;

[0016] If the passability parameter of the cell is greater than or equal to 0 and less than or equal to 1, determine that the cell is a passable cell; or

[0017] If the passability parameter of the cell is less than 0, determine that the cell is an impassable cell.

[0018] Optionally, constructing the locally passable map based on the motion performance parameters of the legged robot and the local map further includes:

[0019] Calculate the average value of the passability parameters of all cells within the projection range of the legged robot, where the projection range is the range enclosing the projected area of the legged robot on the horizontal plane;

[0020] Determine the passability of the projection range based on the average value;

[0021] If the average value is greater than or equal to 0 and less than or equal to 1, determine that the projection range is passable; or

[0022] If the average value is less than 0, determine that the projection range is impassable;

[0023] Construct the local passable map based on the passability of all projection ranges within the local map.

[0024] Optionally, the constructing of the local passable map based on the motion performance parameters of the legged robot and the local map further includes:

[0025] Set a slope filter to calculate the slope of the ramp, set a terrain roughness filter to calculate the ground roughness, set a step height filter to calculate the step height, and set a suspended layer height filter to calculate the suspended height.

[0026] Optionally, the setting of the slope filter to calculate the slope of the ramp includes:

[0027] The slope filter fits a circular plane with the center of the cell as the center and a preset radius in the surrounding area of the cell, and calculates the angle between the normal of the circular plane and the z-axis of the global coordinate system as the slope of the ramp.

[0028] Optionally, the setting of the terrain roughness filter to calculate the ground roughness includes:

[0029] The terrain roughness filter fits a circular plane with the center of the cell as the center and a preset radius in the surrounding area of the cell, and calculates the standard deviation of the heights of all cells within the circular plane as the ground roughness.

[0030] Optionally, the setting of the step height filter to calculate the step height includes:

[0031] The step height filter fits a circular plane with the center of the cell as the center and a preset radius in the surrounding area of the cell;

[0032] Calculate the local height differences of multiple cells within a preset window around each cell within the circular plane, where the preset window includes x * x cells and x is an odd number;

[0033] If the maximum height difference between any cell within the preset window and the central cell of the preset window is greater than the step height critical value h crit and the slope between the corresponding two terrains is greater than the slope critical value s crit, store the maximum height difference as the temporary step height h of the central cell of the preset window temp ;

[0034] Calculate the step height of the central cell in the circular plane h max is the maximum value of the temporary step height h of the cells in the circular plane, and n temp is the number of cells in the circular plane where the temporary step height h st is higher than the step height critical value h temp , and n crit is the number of valid cells where the temporary step height h crit is higher than the step height critical value h temp . crit

[0035] Optionally, the setting of the overhang layer height filter to calculate the overhang height includes:

[0036] The overhang layer height filter fits a circular plane with the center of the cell as the center and a preset radius in the area around the cell;

[0037] Calculate the local height differences of multiple cells within a preset window around each cell in the circular plane, where the preset window includes x * x cells and x is an odd number;

[0038] If the maximum height difference between any cell in the preset window and the central cell of the preset window is greater than the critical value f of the overhang height from the ground crit , and the slope between the corresponding two terrains is greater than the critical value s of the slope crit , store the maximum height difference as the temporary overhang height f from the ground of the central cell of the preset window temp ;

[0039] Calculate the overhang height from the ground of the central cell of the circular plane f max is the maximum value of the temporary overhang height f from the ground of the cells in the circular plane, and n temp is the number of cells in the circular plane where the temporary overhang height h from the ground st is higher than the critical value h of the overhang height from the ground temp , and n crit is the number of cells where the temporary overhang height h from the ground crit is higher than the critical value h of the overhang height from the ground temp . crit

[0040] Optionally, the method further includes:

[0041] When constructing the local map, if a convex obstacle and / or a hole is detected, screen the convex obstacle and / or the hole on the local map, and mark the screened convex obstacle and / or hole as an impassable obstacle.

[0042] Optionally, the legged robot has a preset step length, and the constructing of the local passable map further includes:

[0043] Judge whether the legged robot can pass based on a plurality of preset constraint conditions, and the plurality of preset constraint conditions include:

[0044] If the width of the hole is less than the preset step length, determine that the legged robot can pass through the hole;

[0045] If the inclination of the terrain where the legged robot is located is greater than the preset inclination limit value, determine that the legged robot cannot pass through the terrain;

[0046] If the width of the slope area with an inclination greater than the preset inclination limit value is less than the preset step length, determine that the legged robot can pass through the slope area;

[0047] If the width of the ground area with a roughness greater than the roughness critical value is less than the preset step length, determine that the footprint of the legged robot can pass through the ground area.

[0048] Optionally, the determining of the local target node of the legged robot includes:

[0049] Taking the current position of the legged robot as the center, determine a preset radius range including at least one node on the global path, and determine the node farthest from the legged robot within the preset radius range as the local target node.

[0050] This application also provides an electronic device, and the electronic device includes:

[0051] A processor; and

[0052] A memory, and a plurality of program modules are stored in the memory, and the plurality of program modules are loaded and executed by the processor to perform the above-mentioned path planning method of the legged robot.

[0053] This application also provides a computer-readable storage medium, on which at least one computer instruction is stored, and the instruction is loaded and executed by the processor to perform the above-mentioned path planning method of the legged robot.

[0054] The path planning method, electronic device, and storage medium of the legged robot of the present application can plan the global topological path. At the same time, it can also identify complex terrains on the running path through the sensing information of the legged robot, and intelligently analyze whether the legged robot can pass through the complex terrain. Based on the passability, the real-time position of the robot, and the target nodes of the global topological path, it plans and updates the local path until the legged robot reaches the target position, enabling the legged robot to autonomously pass through or avoid complex terrains and improving the adaptability of the legged robot to the outdoor environment. Description of the Drawings

[0055] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only the embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on the provided drawings.

[0056] Figure 1 It is a schematic diagram of the application environment architecture of the path planning method of the legged robot provided by a preferred embodiment of the present application.

[0057] Figure 2 It is a schematic diagram of the modules of the legged robot provided by a preferred embodiment of the present application.

[0058] Figure 3 It is a three-dimensional schematic diagram of the legged robot provided by a preferred embodiment of the present invention.

[0059] Figure 4 It is a flowchart of the path planning method of the legged robot provided by a preferred embodiment of the present application.

[0060] Figure 5 It is a schematic diagram of the topological map provided by a preferred embodiment of the present application.

[0061] Figure 6 It is a schematic diagram of the local map provided by a preferred embodiment of the present application.

[0062] Figure 7 It is a flowchart of constructing the local passable map provided by a preferred embodiment of the present application.

[0063] Figure 8 It is a schematic diagram of the height line during the movement of the legged robot provided by a preferred embodiment of the present application.

[0064] Figure 9 It is a schematic diagram of the structure of the electronic device provided by a preferred embodiment of the present application.

[0065] Main Component Symbol Description

[0066] Electronic device 1

[0067] Processor 10

[0068] Memory 20

[0069] Computer program 30

[0070] Legged robot 100

[0071] Mechanical unit 101

[0072] Communication unit 102

[0073] Audio output unit 103

[0074] Sensing unit 105

[0075] Display unit 106

[0076] User input unit 107

[0077] Interface unit 108

[0078] Storage unit 109

[0079] Main control unit 110

[0080] Power supply 111

[0081] Drive unit 1011

[0082] Power module 1012

[0083] Mechanical structure module 1013

[0084] Airframe 10131

[0085] Leg structure 10132

[0086] Foot structure 10134

[0087] Display panel 1061

[0088] Touch panel 1071

[0089] Input device 1072

[0090] Server 2

[0091] The following specific embodiments will further illustrate the present application in conjunction with the above-mentioned drawings. Specific embodiments

[0092] In order to more clearly understand the above objects, features, and advantages of the present application, the present application will be described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, without conflict, the embodiments of the present application and the features in the embodiments may be combined with each other.

[0093] In the following description, many specific details are set forth in order to provide a thorough understanding of the present application. The described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present application without creative efforts shall fall within the scope of protection of the present application.

[0094] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which this application belongs. The terms used in the specification of this application herein are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0095] In the subsequent description, suffixes such as "module", "component", or "unit" used to represent components are only for the convenience of describing the present invention, and they have no specific meaning in themselves. Therefore, "module", "component", or "unit" can be used interchangeably.

[0096] Please refer to Figure 1 As shown, it is a schematic diagram of the application environment architecture of the path planning method for a legged robot provided by a preferred embodiment of the present application.

[0097] The path planning method for the legged robot in the present application is applied in the electronic device 1, and the electronic device 1 can establish a communication connection with at least one legged robot 100 and at least one server 2 through a network. The network can be a wired network or a wireless network, such as radio, Wireless Fidelity (WIFI), cellular, satellite, broadcast, etc. The cellular network can be a 4G network or a 5G network.

[0098] The electronic device 1 can be an electronic device installed with a path planning program, such as a smart phone, a personal computer, a server, etc. Among them, the server can be a single server, a cloud server, or a server cluster, etc. The server 2 can be a single server, a cloud server, or a server cluster, etc.

[0099] Please refer to Figure 2As shown, it is a schematic diagram of the hardware structure of a legged robot 100 for implementing a preferred embodiment of the present application. The legged robot 100 may include: a mechanical unit 101, a communication unit 102, an audio output unit 103, a sensing unit 105, an interface unit 108, a storage unit 109, a main control unit 110, and a power supply 111 and other components. The various components of the legged robot 100 can be connected in any way, including wired or wireless connections, etc. Those skilled in the art can understand that Figure 2 The shown structure of the legged robot 100 does not constitute a limitation on the legged robot 100. The legged robot 100 may include more or fewer components than shown, and some components are not essential components of the legged robot 100 and can be omitted or combined with some components entirely according to needs within the scope of not changing the essence of the invention.

[0100] Next, in combination with Figure 3 Specific introductions will be made to the various components of the legged robot 100:

[0101] The mechanical unit 101 is the hardware of the legged robot 100. The mechanical unit 101 may include at least one driving unit 1011, at least one power module 1012, and a mechanical structure module 1013. The power module 1012 may include a motor and a speed reducer. As Figure 3As shown, the mechanical structure module 1013 may include a fuselage 10131, an extendable leg structure 10132, and a foot structure 10134. In other embodiments, the mechanical structure module 1013 may further include an extendable robotic arm, a rotatable head structure, a wagging tail structure, a load-carrying structure, a saddle structure, a camera structure, etc. It should be noted that each component module of the mechanical unit 101 may be one or multiple, which can be set according to specific situations. For example, the leg structure 10132 is generally 4, and each leg structure 10132 is configured with 3 power modules 1012, which respectively correspond to the side-swing leg joint, the thigh joint, and the calf joint. The number of power modules 1012 corresponding to the legged robot 100 is 12. The drive unit 1011 drives the corresponding power module 1012 to work by outputting a driving torque. Multiple power modules 1012 cooperate with each other to control the mechanical structure module 1013 to perform quadruped walking. In at least one embodiment of the present invention, the motor in the power module 1012 is a high-torque three-phase DC motor. In other embodiments, the motor in the power module 1012 may also be a single-phase motor. The operating voltage range of the motor of the power module 1012 is 36 - 48 volts (V). The rated drive current of the motor of the power module 1012 is 5 amperes (A), and the maximum torque can reach 6 newton-meters (NM). The maximum rotational speed of the motor of the power module 1012 can be 2000 revolutions per minute (RPM). The rated power of the motor of the power module 1012 is 600 watts (W). In at least one embodiment of the present invention, multiple power modules 1012 may correspond to the same drive unit 1011. In other embodiments, each power module 1012 may correspond to a drive unit 1011, that is, the number of drive units 1011 is the same as the number of power modules 1012.

[0102] The communication unit 102 can be used for signal reception and transmission, and can also communicate with the network and other devices. For example, after receiving instruction information sent by a remote control or other legged robots 100 to move in a specific gait at a specific speed in a specific direction, it transmits it to the main control unit 110 for processing. The communication unit 102 includes, such as, a WiFi module, a 4G module, a 5G module, a Bluetooth module, an infrared module, etc.

[0103] The audio output unit 103 can convert the audio data received by the communication unit 102 or stored in the storage unit 109 into an audio signal and output it as sound. The audio output unit 103 may include a speaker, a buzzer, etc.

[0104] The sensing unit 105 is configured to obtain information data of the surrounding environment of the legged robot 100 and monitor the motion parameters of each component inside the legged robot 100, and send them to the main control unit 110. The sensing unit 105 includes a variety of sensors, such as sensors for obtaining surrounding environment information: lidar (for remote object detection, distance determination, and / or speed determination), millimeter-wave radar (for short-range object detection, distance determination, and / or speed determination), cameras, infrared cameras, Global Navigation Satellite System (GNSS), etc. Such as sensors for monitoring each component inside the legged robot 100: Inertial Measurement Unit (IMU) (for measuring values of speed, acceleration, and angular velocity), sole sensors (for monitoring the position of the sole contact point, sole posture, magnitude and direction of the ground contact force), and temperature sensors (for detecting the temperature of components), but not limited thereto. As for other sensors that the legged robot 100 may also be configured with, such as load sensors, touch sensors, motor angle sensors, torque sensors, etc., they will not be elaborated here.

[0105] The display unit 106 is configured to display information input by the user or information provided to the user. The display unit 106 may include a display panel 1061, and the display panel 1061 can be configured in forms such as a Liquid Crystal Display (LCD), an Organic Light-Emitting Diode (OLED), etc.

[0106] The user input unit 107 can be used to receive input digital or character information. Specifically, the user input unit 107 may include a touch panel 1071. The touch panel 1071, also known as a touch screen, can collect the user's touch operations (such as operations of the user using the palm, finger, or suitable accessory on or near the touch panel 1071), and drive the corresponding connection device according to a pre-set program. The touch panel 1071 may include two parts: a touch detection device and a touch controller. Among them, the touch detection device detects the user's touch position and detects the signal brought by the touch operation, and transmits the signal to the touch controller. The touch controller receives the touch information from the touch detection device, converts it into contact coordinates, and then sends it to the main control unit 110, and can receive and execute the commands sent by the main control unit 110. In addition to the touch panel 1071, the user input unit 107 may also include other input devices 1072. Specifically, the other input devices 1072 may include, but are not limited to, one or more of a remote control operation handle, etc., and are not specifically defined here.

[0107] Further, the touch panel 1071 may cover the display panel 1061. After the touch panel 1071 detects a touch operation on or near it, it transmits the touch operation to the main control unit 110 to determine the type of touch event. Subsequently, the main control unit 110 provides a corresponding visual output on the display panel 1061 according to the type of touch event. Although in Figure 1 , the touch panel 1071 and the display panel 1061 are implemented as two independent components to separately perform input and output functions, in some embodiments, the touch panel 1071 and the display panel 1061 may be integrated to implement input and output functions, and specific details are not limited herein.

[0108] The interface unit 108 can be used to receive inputs from external devices (such as data information, power, etc.) and transmit the received inputs to one or more components within the legged robot 100, or can be used to output to external devices (such as data information, power, etc.). The interface unit 108 may include a power port, a data port (such as a USB port), a memory card port, a port for connecting a device with an identification module, an audio input / output (I / O) port, a video I / O port, etc.

[0109] The storage unit 109 is used to store software programs and various data. The storage unit 109 may mainly include a program storage area and a data storage area. Among them, the program storage area may store an operating system program, a motion control program, application programs (such as a text editor), etc.; the data storage area may store data generated during the use of the legged robot 100 (such as various sensing data obtained by the sensing unit 105, log file data), etc. In addition, the storage unit 109 may include a high-speed random access memory, and may also include a non-volatile memory, such as a disk memory, a flash memory, or other non-volatile solid-state memories.

[0110] The main control unit 110 is the control center of the legged robot 100, connecting various components of the entire legged robot 100 through various interfaces and lines. By running or executing the software programs stored in the storage unit 109 and calling the data stored in the storage unit 109, the main control unit 110 performs overall control of the legged robot 100.

[0111] The power supply 111 is used to supply power to each component. The power supply 111 includes a battery and a power control board. The power control board is used to control functions such as battery charging, discharging, and power consumption management. Optionally, the power supply 111 can be electrically connected to the main control unit 110, the drive unit 1011, and the sensing unit 105 (such as a camera, radar, speaker, etc.). It should be noted that each component can be connected to different power supplies 111 respectively, or powered by the same power supply 111.

[0112] Please refer to Figure 4 As shown, it is a flowchart of the path planning method for a legged robot provided by a preferred embodiment of the present application. According to different requirements, the order of steps in the flowchart can be changed, and some steps can be omitted.

[0113] In an embodiment of the present application, the path planning method for the legged robot is applied to an electronic device 1 wirelessly communicatively connected to the legged robot 100.

[0114] S401, obtain the starting position information, the target position information, and the global map of the surrounding environment, and plan the global path of the legged robot.

[0115] In an embodiment, the surrounding environment of the legged robot is an indoor environment, an outdoor environment, or a combination of an indoor environment and an outdoor environment, and the global map of the surrounding environment is a global topological map.

[0116] In an embodiment, obtaining the starting position information, the target position information, and the global map of the surrounding environment includes: before the electronic device performs path planning, obtaining the starting position information and the target position information input by the user, and downloading at least one global topological map of the indoor movement environment and / or the outdoor movement environment of the legged robot from the server. In other embodiments, the electronic device can also pre-store at least one global topological map of the indoor movement environment and / or the outdoor movement environment of the legged robot. Among them, the topological map is composed of elements such as nodes, ways, relations, and tags. Among them, the node represents the coordinate point of a certain position (such as the coordinates of an intersection, any point on a road, a building, etc.). The way is composed of several nodes and is used to represent streets, parks, sidewalks, etc. The relation represents the relationship between several nodes and ways and is used to create complex shapes, etc. The tag is used for information of nodes or ways, such as a certain road being a one-way street, the maximum speed of a certain road, etc. The starting position information and the target position information can be longitude and latitude information or node information.

[0117] In one embodiment, the global path includes at least one node, which is a node in the global topological map. Planning the global path of the legged robot includes: through a path planning algorithm, based on multiple nodes in the at least one global topological map, planning the shortest path from the starting position to the target position as the global path. Please refer to Figure 5 As shown, assuming the starting position is node A and the target position is node B, route a is the shortest path from the starting position node A to the target position node B, that is, the global path.

[0118] In one embodiment, the path planning algorithm is the A* algorithm. The A* algorithm is a heuristic search algorithm that establishes heuristic search rules during the search process to measure the distance relationship between the real-time position and the target position, so that the search direction preferentially faces the direction of the target point. In other embodiments, the path planning algorithm can also be the Dijkstra algorithm, D* algorithm, LPA* algorithm, or D*lite algorithm.

[0119] S402, obtain the sensing information of the surrounding environment and construct a local map.

[0120] In one embodiment, the local map covers at least one node on the global path.

[0121] In one embodiment, obtaining the sensing information of the surrounding environment includes: when the legged robot starts to move in the surrounding environment from the starting position node A, obtaining the sensing information of the surrounding environment at preset time intervals through the sensing unit, and transmitting the sensing information to the electronic device through the wireless communication network. Optionally, the preset time interval is thirty seconds.

[0122] In one embodiment, the local map is a height map. Constructing the local map includes: based on the height information within a preset range sensed by the sensing unit of the legged robot and the preset resolution, constructing the local map. Wherein, the height information is the terrain height information within the preset range and / or the height information of any building or structure presented on the terrain. Optionally, the preset range is a range of 20m * 20m, and the preset resolution is 5cm.

[0123] Specifically, the sensing unit can include a lidar and a camera. During the movement of the legged robot, the surrounding environment is scanned and photographed through the lidar and the camera to obtain the landform features of the surrounding environment, extract the terrain height information within the surrounding environment, and construct a local map as Figure 6 shown.

[0124] Further, in one embodiment, constructing the local map further includes: when constructing the local map, if a raised obstacle and / or a hole is detected, screening the raised obstacle and / or the hole on the local map, and marking the screened raised obstacle and / or hole as an impassable obstacle.

[0125] Specifically, when constructing the local map, the legged robot can detect raised obstacles based on the ground segmentation and settlement collision detection method and sensing information, and search for surface discontinuities in the lidar point cloud generated based on the sensing information to detect holes. If a raised obstacle and / or a hole is detected, screen the raised obstacle and / or the hole on the local map, and mark the raised obstacle and / or the hole on the local map. For example, semantic information is used for marking, that is, the text "obstacle" is marked in the area of the raised obstacle and / or the hole on the local map. In this way, raised obstacles such as walls and large stones, and holes such as large pits and uncovered sewers can be directly regarded as obstacles and displayed on the local map, and subsequent analysis of the obstacle area is not required, thus greatly reducing the calculation time consumption.

[0126] S403. Construct a local passable map based on the motion performance parameters of the legged robot and the local map.

[0127] In one embodiment, the motion performance parameters of the legged robot include at least one of a height threshold for crossing a step, a roughness threshold for passing through the ground, a slope threshold for passing through a slope, and a height threshold for passing through a suspended object.

[0128] Please refer to Figure 7 As shown, the detailed process of constructing a local passable map based on the motion performance parameters of the legged robot and the local map includes:

[0129] S4031. Divide the projection plane of the local map into multiple cells.

[0130] In one implementation, as Figure 6 shown, divide the projection plane of the local map on the XY plane of a three-dimensional rectangular coordinate system (global coordinate system) into the multiple cells. Optionally, the size of the cell is the same as the resolution of the local map, which is also 5 cm * 5 cm.

[0131] S4032. Based on the motion performance parameters, set a slope filter to calculate the slope of the slope, set a terrain roughness filter to calculate the ground roughness, set a step height filter to calculate the step height, and set a suspended layer height filter to calculate the suspended height.

[0132] In one embodiment, the slope filter is used to filter out slopes that a legged robot can pass through in the local map, the terrain roughness filter is used to filter out road surfaces such as gravel that the legged robot can cross in the local map, the step filter is used to filter out steps or stairs that the legged robot can cross in the local map, and the suspended layer height filter is used to filter out suspended objects (such as under a table, under a bridge, an underground passage, etc.) that the legged robot can cross in the local map.

[0133] Specifically, setting the slope filter to calculate the slope of the slope includes: the slope filter fits a circular plane with the center of the cell as the center and a preset radius in the area around the cell, and then calculates the angle between the normal of the circular plane and the Z-axis of the global coordinate system as the slope of the slope. Wherein, the preset radius is greater than the radius of the inscribed circle of the projection formed after the projection of the legged robot on the XY plane of the global coordinate system.

[0134] Setting the terrain roughness filter to calculate the ground roughness includes: the terrain roughness filter fits a circular plane with the center of the cell as the center and a preset radius in the area around the cell, and calculates the standard deviation of the heights of all cells in the circular plane as the ground roughness.

[0135] Setting the step height filter to calculate the step height includes: the step height filter fits a circular plane with the center of the cell as the center and a preset radius in the area around the cell, and calculates the local height difference of multiple cells in a preset window around each cell in the circular plane. The preset window includes x * x cells, and x is an odd number; if the maximum height difference between any cell in the preset window and the central cell of the preset window is greater than the step height critical value h crit and the slope between the corresponding two terrains is greater than the slope critical value s crit , store the maximum height difference as the temporary step height h of the central cell of the preset window temp ; calculate the step height of the central cell in the circular plane Wherein, h max is the maximum value of the temporary step height h of the cells in the circular plane temp , n st is the number of cells in the circular plane whose temporary step height h temp is higher than the step height critical value h crit , n crit is the number of valid cells whose temporary step height h temp is higher than the step height critical value h crit . Optionally, the number of valid cells is 10.

[0136] Setting the overhanging layer height filter to calculate the overhanging height includes: The overhanging layer height filter fits a circular plane with the center of the cell as the center and a preset radius in the area around the cell, calculates the local height differences of multiple cells within a preset window around each cell in the circular plane, the preset window includes x * x cells, and x is an odd number; if the maximum height difference between any cell in the preset window and the central cell of the preset window is greater than the critical value f of the overhanging height from the ground crit , and the slope between the corresponding two terrains is greater than the critical value s of the slope crit , store the maximum height difference as the temporary overhanging height f from the ground of the central cell of the preset window temp ; calculate the overhanging height from the ground of the central cell of the circular plane where f max is the maximum value of the temporary overhanging height f from the ground of the cells in the circular plane, n temp is the number of cells in the circular plane whose temporary overhanging height h from the ground st is higher than the critical value h of the overhanging height from the ground, n temp is the number of valid cells whose temporary overhanging height h from the ground crit is higher than the critical value h of the overhanging height from the ground crit is the number of valid cells whose temporary overhanging height h from the ground temp is higher than the critical value h of the overhanging height from the ground crit . Optionally, the number of valid cells is 10.

[0137] S4033. Calculate the passability parameter of each cell according to the motion performance parameter and the local map.

[0138] In one embodiment, the passability parameter t = 1 - d, where d is the danger value where α 1 , α 2 , α 3 and α 4 are preset coefficients, α 1 +α 2 +α 3 +α 4 = 1, s is the slope of the cell, s crit is the critical value of the slope, r is the ground roughness, r crit is the critical value of the ground roughness of the cell, h is the step height of the cell, h crit is the critical value of the step height, f is the overhanging height of the cell, f ceil is the upper limit value of the overhanging height from the ground of the cell, f floor is the lower limit value of the overhanging height from the ground of the cell.

[0139] In one embodiment, refer to Figure 8 As shown, the solid line c represents the ground, the dashed line a represents the upright walking height line of the legged robot, the dashed line b represents the crawling walking height line of the legged robot, and the solid line d represents the actual suspended layer height, and the suspended layer height is determined based on the local map. If the suspended layer height is greater than the upper limit value f of the suspended height of the cell from the ground ceil , then the legged robot can pass through the suspended layer. If the suspended layer height is less than the lower limit value f of the suspended height of the cell from the ground floor , then the legged robot cannot pass through the suspended layer. The difference between the upper limit value f of the suspended height of the cell from the ground and the actual suspended layer height can be used to determine whether the legged robot can pass through the suspended layer. ceil

[0140] S4034, if the passability parameter of the cell is greater than or equal to 0 and less than or equal to 1, determine that the cell is a passable cell, that is, the legged robot can pass through the cell. It should be noted that the greater the danger value, the smaller the passability parameter, indicating that it is more difficult for the legged robot to pass through.

[0141] S4035, if the passability parameter of the cell is less than 0, determine that the cell is an impassable cell, that is, the legged robot cannot pass through the cell.

[0142] In one embodiment, if the danger value is infinite, the passability parameter of the cell is less than 0 and infinitesimal, determine that the legged robot cannot pass through the cell. Specifically, if any of the following conditions is met: the slope gradient is greater than the slope critical value, the ground roughness is greater than the ground roughness critical value, the step height is greater than the step height critical value, and the difference between the upper limit value of the suspended height of the cell from the ground and the suspended height is greater than the difference between the upper limit value of the suspended height of the cell from the ground and the lower limit value of the suspended height of the cell from the ground, determine that the danger value is infinite.

[0143] S4036, calculate the average value of the passability parameters of all cells within the projection range of the legged robot.

[0144] In one embodiment, the projection range is the range that envelopes the projected area of the legged robot on the horizontal plane.

[0145] S4037, determine the passability tf of the projection range based on the average value.

[0146] In one embodiment, the passability tf of the footprint is represented by 0 or 1. If the average value is greater than or equal to 0 and less than or equal to 1, it is determined that the projection range is passable, and the passability tf of the projection range is set to 1. If the average value is less than 0, it is determined that the projection range is impassable, and the passability tf of the projection range is set to 0.

[0147] S4038. Construct the local passable map based on the passabilities of all projection ranges within the local map.

[0148] In one embodiment, mark the passabilities of all footprints on the local map, and combine the footprints with a passability tf of 1 to construct the local passable map.

[0149] The legged robot has a preset step length, which is the maximum distance that the foot structure of the legged robot can span in each step during movement.

[0150] In other embodiments, the constructing of the local passable map further includes: judging whether the legged robot can pass based on a plurality of preset constraint conditions. The plurality of preset constraint conditions include: if the width of the hole is less than the preset step length, it is determined that the legged robot can pass through the hole; if the inclination of the terrain where the legged robot is located is greater than the preset inclination limit value, it is determined that the legged robot cannot pass through the terrain; however, if the width of the slope area with a slope greater than the preset inclination limit value is less than the preset step length, it is determined that the legged robot can pass through the slope area; if the width of the ground area with a roughness greater than the roughness critical value is less than the preset step length, it is determined that the legged robot can pass through the ground area.

[0151] It should be noted that if the width of the hole is less than the preset step length, it means that the hole is a gap with a small width, and the legged robot can directly cross it in a single step, so it is not regarded as an obstacle. In addition, there may be a situation where the slope of a cell is less than or equal to the slope critical value, while the overall inclination of the terrain where the cell is located is greater than the preset inclination limit value. To avoid slipping or tipping over, it is determined that the legged robot cannot pass through the terrain. For a slope area with a large slope, since its width is small, the legged robot can cross it in a single step, so it is determined that the legged robot can pass through the slope area. For a ground area with a large roughness, since its width is small, the legged robot can cross it in a single step, so it is determined that the legged robot can pass through the ground area.

[0152] S404. Determine the local target node of the legged robot based on the global path and the current position of the legged robot.

[0153] In one embodiment, the current position of the legged robot is longitude and latitude information. Determining the local target node of the legged robot includes: taking the current position of the legged robot as the center of a circle, determining a preset radius range that includes at least one node on the global topological path, and determining the node that is the farthest from the legged robot within the preset radius range as the local target node.

[0154] As Figure 5 shown, for example, the current position of the legged robot is point O. Taking point O as the center of a circle, a preset radius range that includes node D on the global topological path is determined, and node D is determined as the node that is the farthest from the legged robot within the preset radius range, that is, node D is the local target node.

[0155] It should be noted that as the legged robot continues to move, the local target node can be continuously updated until the target position is reached.

[0156] S405. Based on the local map, the local passable map, the local target node, and the current position of the legged robot, plan the local path of the legged robot.

[0157] In one embodiment, since the position of the legged robot needs to remain in contact with the ground, the local path is a 2.5D path. Each point on the local path has the X-axis coordinate and Y-axis coordinate of the global coordinate system. According to the X-axis coordinate, Y-axis coordinate, and local elevation map of each point, the Z-axis coordinate, that is, the height, corresponding to each point can be obtained.

[0158] In one embodiment, based on the local map, the local passable map, the local target node, and the current position of the legged robot, planning the local path of the legged robot includes: selecting the passable projection range on the local passable map, and planning the shortest path from the current position of the legged robot to the local target node using the passable projection range through a path planning algorithm. Optionally, the path planning algorithm is the A* algorithm.

[0159] In one embodiment, the electronic device sends the planned local path of the legged robot to the legged robot, so that the legged robot performs autonomous movement under the navigation of the local path.

[0160] S406. Update the local path until the legged robot reaches the target position.

[0161] In one embodiment, as the legged robot continues to move, the local map, the local passable map, and the local target nodes are updated every preset time period, and then the updated local path is planned and the updated local path is tracked until the legged robot reaches the target position, finally completing the autonomous path planning and autonomous movement in a large-scale complex environment.

[0162] Further, the method further includes: performing path tracking planning, dynamic obstacle avoidance planning, and corresponding motion control of the legged robot based on the local path and dynamic obstacles sensed by the legged robot.

[0163] It can be understood that during the process of the legged robot moving autonomously based on the local path, it may encounter dynamic obstacles, such as pedestrians, animals, vehicles, etc. The legged robot can send the sensed obstacle information to the electronic device, and the electronic device makes decisions on the motion control of the legged robot based on the obstacle information, such as sending instructions to control the legged robot to turn, pause, accelerate, decelerate, etc., so as to avoid dynamic obstacles and achieve the path tracking planning, dynamic obstacle avoidance planning, and corresponding motion control of the legged robot.

[0164] In other embodiments of the present application, the legged robot may also be the electronic device itself, which autonomously performs path planning, including constructing a global path based on the global map, constructing a local map based on the sensed information, calculating passability parameters to construct a passable map, planning and updating local target nodes and local paths, autonomously moving along the continuously updated local path to the target position, and performing autonomous obstacle avoidance when encountering dynamic obstacles during the movement process. In this way, there is no need to transmit the sensed information to other electronic devices, nor to receive the local path and obstacle avoidance motion control planned by other electronic devices, thereby reducing the delay in the path planning and autonomous movement processes and improving the movement efficiency.

[0165] Please refer to Figure 9 shown, which is a schematic structural diagram of an electronic device provided by a preferred embodiment of the present application.

[0166] The electronic device 1 includes, but is not limited to, a processor 10, a memory 20, a computer program 30 stored in the memory 20 and executable on the processor 10, a slope filter 40, a terrain roughness filter 50, a step height filter 60, and a suspended layer height filter 70. For example, the computer program 30 is a route planning program. When the processor 10 executes the computer program 30, it implements the steps in the path planning method of the legged robot, such as Figure 4 the steps S401 - S403 shown, Figure 7 the S4031 - S4038 shown.

[0167] It should be noted that if the legged robot is the electronic device 1, the processor 10 is the main control unit 110, and the memory 20 is the storage unit 109.

[0168] Exemplarily, the computer program 30 can be divided into one or more modules / units. The one or more modules / units are stored in the memory 20 and executed by the processor 10 to complete the present application. The one or more modules / units can be a series of computer program instruction segments capable of performing specific functions, and the instruction segments are used to describe the execution process of the computer program 30 in the electronic device 1.

[0169] Those skilled in the art can understand that the schematic diagram is only an example of the electronic device 1, and does not constitute a limitation on the electronic device 1. It may include more or fewer components than shown in the figure, or combine some components, or different components. For example, the electronic device 1 may further include input / output devices, network access devices, buses, etc.

[0170] The processor 10 can be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor can be a microprocessor, or the processor 10 can also be any conventional processor, etc. The processor 10 is the control center of the electronic device 1, and connects various parts of the entire electronic device 1 through various interfaces and lines.

[0171] The memory 20 can be used to store the computer program 30 and / or modules / units. By running or executing the computer program and / or modules / units stored in the memory 20, and invoking the data stored in the memory 20, the processor 10 realizes various functions of the electronic device 1. The memory 20 mainly includes a program storage area and a data storage area. Among them, the program storage area can store an operating system, application programs required for at least one function (such as a sound playback function, an image playback function, etc.); the data storage area can store data created according to the use of the electronic device 1 (such as audio data, phone book, etc.). In addition, the memory 20 can include volatile and non-volatile memories, such as a hard disk, a memory, a plug-in hard disk, a Smart Media Card (SMC), a Secure Digital (SD) card, a Flash Card, at least one magnetic disk storage device, a flash memory device, or other storage devices.

[0172] The slope filter 40 is a computer program for calculating the slope of a ramp, the terrain roughness filter 50 is a computer program for calculating the ground roughness, the step height filter 60 is a computer program for calculating the step height, and the overhanging layer height filter 70 is a computer program for calculating the overhanging height.

[0173] If the modules / units integrated in the electronic device 1 are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, to implement all or part of the processes in the above method embodiments of the present application, it can also be completed by instructing relevant hardware through a computer program. The computer program can be stored in a computer-readable storage medium. When the computer program is executed by a processor, the steps of the above method embodiments can be implemented. Among them, the computer program includes computer program code, and the computer program code can be in the form of source code, object code, an executable file, or some intermediate form, etc. The computer-readable medium can include: any entity or device capable of carrying the computer program code, a recording medium, a USB flash drive, a mobile hard disk, a magnetic disk, an optical disc, a computer memory, a read-only memory (ROM), a random access memory (RAM).

[0174] The extended content of the specific embodiments of the computer-readable storage medium described in the present application is basically the same as that of the embodiments of the path planning method of the above-mentioned legged robot, and will not be elaborated here.

[0175] The path planning method, electronic device, and storage medium of the legged robot provided by this application can plan the global topological path. At the same time, it can also identify complex terrains on the running path through the sensing information of the legged robot, and intelligently analyze whether the legged robot can pass through the complex terrains. Based on the passability, the real-time robot position, and the target nodes of the global topological path, it plans and updates the local path until the legged robot reaches the target position, enabling the legged robot to autonomously pass through or avoid complex terrains, and improving the adaptability of the legged robot to the outdoor environment.

[0176] For those skilled in the art, it is obvious that this application is not limited to the details of the above exemplary embodiments, and without departing from the spirit or basic characteristics of this application, this application can be implemented in other specific forms. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting. The scope of this application is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included in this application. Any reference signs in the claims should not be regarded as limiting the claimed rights. In addition, it is obvious that the word "comprising" does not exclude other units or steps, and the singular does not exclude the plural. The multiple units or devices stated in the device claims can also be implemented by the same unit or device through software or hardware. First, second, etc. are used to denote names and do not represent any specific order.

[0177] The above embodiments are only used to illustrate the technical solutions of this application and not to limit them. Although this application has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of this application can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of this application.

Claims

1. A path planning method for a legged robot, characterized in that, the method includes: Obtaining the starting position information, the target position information and the global map of the surrounding environment, and planning the global path of the legged robot, where the global path includes at least one node; Obtaining the sensing information of the surrounding environment and constructing a local map, where the local map covers at least one of the nodes; Construct a local passable map based on the motion performance parameters of the legged robot and the local map, including: dividing the projection plane of the local map into multiple cells; fitting a circular plane with the center of the cell as the center and a preset radius in the area around the cell through a step height filter; calculating the local height differences of multiple cells within a preset window around each cell in the circular plane, the preset window including x*x cells, where x is an odd number; if the maximum height difference between any cell in the preset window and the central cell of the preset window is greater than the step height critical value h crit , and the slope between the corresponding two terrains is greater than the slope critical value s crit , store the maximum height difference as the temporary step height of the central cell of the preset window h temp ; calculate the step height of the central cell in the circular plane , h max is the maximum value of the temporary step height of the cells in the circular plane h temp , n st is the number of cells in the circular plane whose temporary step height h temp is higher than the step height critical value h crit , n crit is the number of valid cells whose temporary step height h temp is higher than the step height critical value h crit , and the motion performance parameters of the legged robot include at least one of the height critical value of the step that can be crossed, the roughness critical value of the ground that can be passed, the slope critical value of the slope that can be passed, and the height critical value of the suspended object that can be passed; Based on the global path and the current position of the legged robot, determining the local target node of the legged robot; Based on the local map, the local passable map, the local target node and the current position of the legged robot, planning the local path of the legged robot; and Updating the local path until the legged robot reaches the target position.

2. The path planning method for a legged robot according to claim 1, characterized in that, the local map is a local elevation map, and the constructing the local passable map based on the motion performance parameters of the legged robot and the local map includes: Calculate the passability parameter of each cell, where the passability parameter t = 1 - d , d is the danger value, , where α 1 , α 2 , α 3 and α 4 are preset coefficients, , s is the slope gradient, s crit is the slope gradient critical value, r is the ground roughness, r crit is the ground roughness critical value, h is the step height, h crit is the step height critical value, f is the suspension height, f ceil is the upper limit value of the suspension height of the cell from the ground, f floor is the lower limit value of the suspension height of the cell from the ground; If the passability parameter of the cell is greater than or equal to 0 and less than or equal to 1, determining that the cell is a passable cell; or If the passability parameter of the cell is less than 0, determining that the cell is an impassable cell.

3. The path planning method for a legged robot according to claim 2, characterized in that, the constructing the local passable map based on the motion performance parameters of the legged robot and the local map further includes: Calculating the average value of the passability parameters of all cells within the projection range of the legged robot, where the projection range is the range enclosing the projected area of the legged robot on the horizontal plane; Determining the passability of the projection range based on the average value; If the average value is greater than or equal to 0 and less than or equal to 1, determining that the projection range is passable; or If the average value is less than 0, determining that the projection range is impassable; Constructing the local passable map based on the passability of all projection ranges within the local map.

4. The path planning method for a legged robot according to claim 2, characterized in that, the constructing the local passable map based on the motion performance parameters of the legged robot and the local map further includes: Setting a slope filter to calculate the slope of the slope, setting a terrain roughness filter to calculate the ground roughness, and setting a suspended layer height filter to calculate the suspended height.

5. The path planning method for a legged robot according to claim 4, characterized in that, the setting a slope filter to calculate the slope of the slope includes: The slope filter fits a circular plane with the center of the cell as the center and a preset radius in the surrounding area of the cell, and calculates the angle between the normal line of the circular plane and the z-axis of the global coordinate system as the slope of the slope.

6. The path planning method for a legged robot according to claim 4, characterized in that, the setting a terrain roughness filter to calculate the ground roughness includes: The terrain roughness filter fits a circular plane with the center of the cell as the center and a preset radius in the area around the cell, and calculates the standard deviation of the heights of all cells within the circular plane as the ground roughness.

7. The path planning method for a legged robot according to claim 4, wherein, the setting of the suspension layer height filter to calculate the suspension height includes: the suspension layer height filter fits a circular plane with the center of the cell as the center and a preset radius in the area around the cell; calculating the local height differences of multiple cells within a preset window around each cell within the circular plane, where the preset window includes x * x cells and x is an odd number; If the maximum height difference between any cell within the preset window and the central cell of the preset window is greater than the critical value of the suspended height from the ground f crit , and the slope between the corresponding two terrains is greater than the critical value of the slope s crit , store the maximum height difference as the temporary suspended height from the ground of the central cell of the preset window f temp ; Calculate the height of the center cell of the circular plane suspended above the ground , f max is the temporary height of the cell in the circular plane suspended above the ground f temp is the maximum value, n st is the temporary height of the cell in the circular plane suspended above the ground h temp higher than the critical value of the height of the cell suspended above the ground h crit is the number of cells, n crit is the temporary height of the cell suspended above the ground h temp higher than the critical value of the height of the cell suspended above the ground h crit is the number of valid cells 8. The path planning method for a legged robot according to claim 1, wherein, the method further includes: when constructing the local map, if a protruding obstacle and / or a hole is detected, screening the protruding obstacle and / or the hole on the local map, and marking the screened protruding obstacle and / or hole as an impassable obstacle.

9. The path planning method for a legged robot according to claim 1 or 8, wherein, the legged robot has a preset step length, and the construction of the local passable map further includes: judging whether the legged robot can pass based on a plurality of preset constraint conditions, where the plurality of preset constraint conditions include: if the width of the hole is less than the preset step length, determining that the legged robot can pass through the hole; if the inclination of the terrain where the legged robot is located is greater than a preset inclination limit value, determining that the legged robot cannot pass through the terrain; if the width of a slope area with an inclination greater than the preset inclination limit value is less than the preset step length, determining that the legged robot can pass through the slope area; if the width of a ground area with a roughness greater than the roughness critical value is less than the preset step length, determining that the footprint of the legged robot can pass through the ground area.

10. The path planning method for a legged robot according to claim 1, wherein, the determination of the local target node of the legged robot includes: with the current position of the legged robot as the center, determining a preset radius range including at least one node on the global path, and determining the node farthest from the legged robot within the preset radius range as the local target node.

11. An electronic device, wherein, the electronic device includes: a processor; and a memory, where a plurality of program modules are stored in the memory, and the plurality of program modules are loaded and executed by the processor to perform the path planning method for a legged robot according to any one of claims 1 to 10.

12. A computer-readable storage medium, on which at least one computer instruction is stored, wherein, the instruction is loaded and executed by the processor to perform the path planning method for a legged robot according to any one of claims 1 to 10.

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