A software architecture system suitable for on-orbit servicing wall-climbing robots

Abstract

The present invention discloses a software architecture system suitable for an on-orbit service wall-climbing robot, which includes a task logic layer, a subtask algorithm layer and a device management layer. The task logic layer includes a main node, which controls the overall task logic of the robot to perform on-orbit service. The task logic is essentially an "operation and maintenance center state machine" that fully considers the safety of the robot to perform on-orbit service. The subtask algorithm layer includes perception planning nodes, behavior nodes, operation and maintenance nodes and communication nodes, which provide various algorithms necessary for the robot to perform on-orbit service and are called by the main node in different states of the "operation and maintenance center state machine". The device management layer includes an environmental sensor management node, a target spacecraft approacher management node, an adsorption motion actuator management node, a track service actuator management node, a power distribution unit management node, and a self-organizing network module management node. Each node of the subtask algorithm layer controls each hardware stand-alone of the robot through the nodes of the device management layer.

Description

Technical Field

[0001] The present invention relates to the technical field of robot software architecture, and in particular to a software architecture of an on-orbit service wall-climbing robot and an implementation method thereof. Background Art

[0002] Wall-climbing robots, also known as wall-moving robots, can replace manual labor in high-altitude wall and narrow space operations. The mobile actuator of the wall-climbing robot must be able to adsorb on the moving surface. Common adsorption methods include magnetic adsorption, negative pressure adsorption, electrostatic adsorption and dry glue adsorption. Wall-climbing robots are currently mainly used in building wall cleaning and spraying, large equipment flaw detection and inspection and other fields.

[0003] In fact, wall-climbing robots are very suitable for on-orbit servicing of spacecraft in orbit, especially for fault detection and repair of spacecraft. The on-orbit servicing wall-climbing robot approaches the target spacecraft through a special spacecraft approach device (which can be a tether device or a jet thrust device, etc.), climbs and moves on the target spacecraft, and performs specific on-orbit tasks.

[0004] At present, most of the software designs for wall-climbing robots focus on a specific sub-task, and only build independent software modules such as autonomous positioning, navigation, and adsorption movement. They neither consider how the robot controls each single machine from the bottom level, nor consider the entire task process directly from the top level. This limits the application of wall-climbing robots in the special application scenario of on-orbit service. Therefore, studying a software architecture suitable for on-orbit service wall-climbing robots has become an issue of concern to us. Summary of the invention

[0005] The purpose of the present invention is to provide a systematic software architecture system for the "on-orbit service wall-climbing robot" to fill the gap in this existing technical field.

[0006] The technical solution adopted by the present invention is specifically as follows:

[0007] A software architecture system suitable for an on-orbit servicing wall-climbing robot adopts a layered software architecture, which includes the following from the top layer to the bottom layer:

[0008] The task logic layer is used to organize the overall process of the wall-climbing robot entering the on-orbit service into a safe and automated task logic, communicate with the subtask algorithm layer, and call the corresponding algorithm of the subtask algorithm layer in different states of the task logic;

[0009] The subtask algorithm layer is used to store various nodes required by the wall-climbing robot for on-orbit service, communicate with the device management layer, obtain sensor information of various devices of the robot, and send various control instructions;

[0010] The device management layer is used to parse the communication protocol between the microprocessors carried by each device of the on-orbit service wall-climbing robot and the robot's main control chip, realize the reading / writing of the upper-level control node to the microprocessors carried by each underlying single machine, and thus realize the effective control of each device of the robot.

[0011] The task logic layer only communicates with the subtask algorithm layer using TCP / IP; the communication protocol between the subtask algorithm layer and the device management layer is TCP / IP.

[0012] The task logic layer contains a master node, which constructs the on-orbit service of the wall-climbing robot into an operation and maintenance center state machine that fully considers the safety of on-orbit service. The overall logic of the "operation and maintenance center state machine" can be summarized as: "The robot must be in good operating condition to perform tasks, otherwise, a series of maintenance operations must be performed to improve the system status."

[0013] The operation and maintenance center state machine contains 5 basic states, including:

[0014] Approaching the spacecraft and landing is used to describe the state of the on-orbit service wall-climbing robot when it has not reached the target spacecraft. In this state, the robot approaches the target spacecraft and stably lands on the target spacecraft, establishes stable adsorption with it, and then automatically enters the waiting command state;

[0015] Waiting command, used to describe that the robot is on the target spacecraft and in standby, can receive external service requests, and will automatically perform self-inspection and maintenance of the robot and enter the system operation and maintenance state;

[0016] System operation and maintenance is used to describe the automatic detection and maintenance of the robot. It is divided into two sub-states: operation detection and maintenance operation. The former detects the operation status of each device of the robot, and the latter maintains the specific equipment of the robot according to the detection results.

[0017] On-orbit service is used to describe the process of the robot being in on-orbit service. The prerequisite for entering this state is that the previous state must be the system operation and maintenance state to ensure that the robot can perform on-orbit service in a good state;

[0018] Autonomous navigation is used to describe the robot in the process of autonomous navigation. The prerequisite for entering this state is that the previous state must be the system operation and maintenance state, so as to ensure that the robot can perform autonomous navigation in a good state and arrive at the waiting service area;

[0019] The subtask algorithm layer includes four types of software nodes, namely perception planning node, behavior node, operation and maintenance node and communication node.

[0020] Each type of software node in the subtask algorithm layer is the code implementation of independent subtasks in the on-orbit service task of the wall-climbing robot: the overall on-orbit service task is divided into four independent subtasks, namely perception planning tasks, actuator control tasks, operation and maintenance tasks, and communication tasks. The implementation of these subtasks in the subtask algorithm layer is the perception planning node, the behavior node, the operation and maintenance node, and the communication node, respectively.

[0021] Each node in the subtask algorithm layer provides various services based on TCP / IP communication and is called by the main node.

[0022] The perception planning node is used for the path planning service of the robot on the target spacecraft. The service obtains environmental sensing information from the environmental sensor management node of the device management layer to construct a mathematical model of the environment, and uses the environmental model to generate the optimal travel trajectory of the robot. The service is called by the main node in the autonomous navigation state.

[0023] The behavior node is used to provide services involving various actuators of the robot, including approaching and landing target spacecraft services, spacecraft surface adsorption and movement services, and on-orbit service services. The service obtains the status of various actuators of the robot from the target spacecraft approaching device management node, the movement and adsorption actuator management node, and the on-orbit service actuator management node of the device management layer, and uses the actuator status to model, plan and control behaviors such as "approaching and landing target spacecraft", "spacecraft surface adsorption and movement", and "on-orbit service". The service is called by the master node in the approaching spacecraft and landing state, the autonomous navigation state, and the on-orbit service state respectively.

[0024] The operation and maintenance node is used to provide operation and maintenance services. The service will obtain the operating status of each robot and each device from the device management layer. If any operational problems occur, maintenance operations will be performed until the robot operation problems are repaired. The service is called by the main node in the system operation and maintenance state.

[0025] The communication node is used to provide communication services, which are divided into receiving services and sending services. The receiving service communicates with the self-organizing network module management node of the device management layer, receives data from the upper computer that is also equipped with a self-organizing network module, and the receiving service is called by the master node in the waiting command state. The sending service communicates with the self-organizing network module management node of the device management layer, sends data to the upper computer that is also equipped with a self-organizing network module, and the sending service is called by the master node.

[0026] The device management layer includes 6 types of software nodes, namely, environmental sensor management node, target spacecraft approach management node, adsorption motion actuator management node, on-orbit service actuator management node, power distribution unit management node, and self-organizing network module management node. Each type of management node parses the communication protocol between the microprocessor carried by each corresponding device of the on-orbit service wall-climbing robot and the robot's main control chip to realize reading / writing of each underlying device.

[0027] Each node of the device management layer has the same structure, and the reading of telemetry signals and the writing of upper-layer commands are determined according to the communication protocol between the microprocessor of each device of the robot and the main control chip of the robot.

[0028] The beneficial effects of the present invention are as follows:

[0029] 1. The system of the present invention provides a layered software architecture suitable for an on-orbit service wall-climbing robot, which has a compact structure and strong practicality.

[0030] 2. From the top level, the software architecture proposed in the present invention fully considers the particularity of on-orbit service missions, especially the safety and stability requirements of the missions. The proposed operation and maintenance center state machine has good robustness and can ensure the safe and stable operation of the on-orbit service wall-climbing robot on the serviced spacecraft to a large extent.

[0031] 3. From the bottom layer, the software architecture proposed in the present invention provides a solution for managing various devices of the on-orbit service wall-climbing robot, which has a certain degree of versatility. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 A schematic diagram of the overall design of the software architecture for the on-orbit servicing wall-climbing robot;

[0033] Figure 2 This is a schematic diagram of the state machine of the operation and maintenance center of the subtask algorithm layer;

[0034] Figure 3 A schematic diagram of the program principle of any device management node in the device management layer;

[0035] Figure 4 is a schematic diagram of a rail-serving wall-climbing robot in a specific implementation scheme;

[0036] Figure 5 A schematic diagram of the overall design of the software architecture of the mid-rail service wall-climbing robot for specific implementation;

[0037] Figure 6 It is a schematic diagram of the state machine of the operation and maintenance center in the specific implementation plan;

[0038] Figure 7 It is a schematic diagram of the perception planning algorithm in the perception planning node in the specific implementation plan;

[0039] Figure 8 It is a schematic diagram of the operation and maintenance algorithm in the operation and maintenance node in the specific implementation plan;

[0040] Fig. 9 This is a diagram of the communication architecture based on ROS. DETAILED DESCRIPTION

[0041] Hereinafter, the present invention will be further described in conjunction with the accompanying drawings and embodiments.

[0042] Embodiment 1:

[0043] The present invention provides a software architecture system suitable for an on-orbit service wall-climbing robot, which adopts a layered software architecture. Figure 1 As shown, from the top layer to the bottom layer, it includes:

[0044] The task logic layer is used to organize the overall process of the wall-climbing robot entering the on-orbit service into a safe and automated task logic, communicate with the subtask algorithm layer, and call the corresponding algorithm of the subtask algorithm layer in different states of the task logic;

[0045] The subtask algorithm layer is used to store various nodes required by the wall-climbing robot for on-orbit service, communicate with the device management layer, obtain sensor information of various devices of the robot, and send various control instructions;

[0046] The device management layer is used to parse the communication protocol between the microprocessors carried by each device of the on-orbit service wall-climbing robot and the robot's main control chip, realize the reading / writing of the upper-level control node to the microprocessors carried by each underlying single machine, and thus realize the effective control of each device of the robot.

[0047] The task logic layer only communicates with the subtask algorithm layer using TCP / IP; the communication protocol between the subtask algorithm layer and the device management layer is TCP / IP.

[0048] The task logic layer contains a master node, which programs the on-orbit service of the wall-climbing robot into an operation and maintenance center state machine that fully considers the safety of the on-orbit service, such as Figure 2 The overall logic of the “Operation and Maintenance Center State Machine” can be summarized as follows: “The robot must be in good operating condition to perform tasks, otherwise, a series of maintenance operations must be performed to improve the system status.”

[0049] Each node in the device management layer has the same structure, such as Figure 3 As shown, the reading of telemetry signals and the writing of upper-level commands are determined according to the communication protocol between the microprocessor of each device of the robot and the main control chip of the robot.

[0050] Embodiment 2:

[0051] The present invention also provides an on-orbit service wall-climbing robot, such as Figure 4 As shown, the on-orbit service performed by the robot is spacecraft surface fault detection. The hardware part of the robot includes:

[0052] The robot main control chip and expansion board 1 are equipped with 1 USB3.0 interface and 4 UART serial ports for stand-alone communication with various hardware of the robot;

[0053] The environmental sensor is a depth camera 2 with a built-in IMU unit, which can obtain the depth map, point cloud and angular velocity of the environment, and communicate with the robot main control chip via USB3.0;

[0054] The spacecraft approacher is composed of a tether mechanism 6 and a drive board 9 installed at the bottom of the robot. The tether mechanism 6 can eject its own capture head onto the target spacecraft, allowing the robot to establish a tether connection with the target spacecraft, and then retract the rope to make the robot approach and land on the spacecraft. The microprocessor built into the drive board communicates with the robot main control chip via UART;

[0055] The service actuator (adsorption motion actuator) is composed of 6 legs formed by 18 bus servos 4 connected in series and an electrostatic adsorption film 5 installed on the leg end, which is symmetrically distributed on the left and right. This mechanism enables the robot to crawl on the surface of the spacecraft by adsorption. The microprocessor it carries is used to communicate with the robot main control chip via UART. In this example, the adsorption motion actuator is equivalent to the service actuator, so both occupy one UART serial port;

[0056] The power distribution unit and other devices include a power distribution unit 8, a battery 7, a solar cell array 12 and an LED lighting lamp 3. The power distribution unit is connected to the power supply device and the power supply device and the power-consuming device. The built-in microprocessor can control the power supply of each power-consuming device of the robot and communicate with the robot main control chip via the UART serial port;

[0057] Self-organizing network module: It is an air-side self-organizing network module 10, which can receive information transmitted by the paired ground-side module within 60 kilometers. The built-in microprocessor communicates with the robot main control chip via UART.

[0058] In combination with the example robot, the "software architecture suitable for on-orbit service wall-climbing robot" provided by the present invention can be applied. Figure 5 This is a specific implementation of the present invention in an example robot, which is mainly reflected in the following aspects

[0059] 1. The task logic layer of the present invention, the "operation and maintenance center" state machine in the master node can be specifically implemented as follows according to the task requirements of the instance: Figure 6 The state machine shown in Figure 1 is as follows. Figure 6 As shown in the figure, state ① is subdivided into three sub-states according to the situation of the example robot, namely, establishing tether connection, retracting tether and adjusting attitude, and landing, which is applicable to the spacecraft approacher based on the tether structure in the example robot. Furthermore, since the example robot performs the task of fault detection on the surface of the spacecraft, the robot needs to perform intelligent and autonomous mobile navigation on the surface of the spacecraft when performing the task, so the on-orbit service state and the autonomous navigation state overlap in function and are merged into one state. In this state, the robot analyzes the spacecraft surface images collected by the depth camera while autonomously navigating on the surface of the spacecraft to check whether there is any fault.

[0060] 2. The communication between the task logic layer and the subtask algorithm layer, and the communication between the subtask algorithm layer and the device management layer of the present invention are maintained by the Robot Operating System (ROS). Each node of the task logic layer, the subtask algorithm layer and the device management layer is designed as a ROS node, and communicates with nodes of other layers in the form of ROS topics (ROSTopic) or ROS services (ROSService) (based on TCP / IP). The main node communicates with each node of the subtask algorithm layer through ROSService, and each node of the subtask algorithm layer communicates with each node of the device management layer in the form of ROSTopic.

[0061] 3. The specific implementation of each node in the subtask algorithm layer of the present invention for the example robot is as follows:

[0062] The perception planning node communicates with the master node and the depth camera management node. It provides the path planning ROS service for the robot on the spacecraft. This ROS service is subscribed by the master node, and obtains the depth map, IMU information, point cloud, and RGB map from the depth camera management node of the device management layer to build a mathematical model of the environment, and uses the environment model and navigation target points to generate the optimal trajectory of the robot. The internal algorithm process is as follows: Figure 7 shown.

[0063] The behavior node communicates with the main node, the depth camera management node, the tether mechanism management node, and the servo and electrostatic adsorption device management node. It provides services involving various actuators of the robot, including "approaching the target spacecraft" (including the three steps of releasing the capture device, retracting the rope and adjusting the attitude, and landing) and "spacecraft surface fault detection" services. The service is called by the main node, and the information required by the service is obtained from the depth camera management node, the tether mechanism management node, and the servo and electrostatic adsorption device management node in the device management layer.

[0064] The operation and maintenance node communicates with the master node and the power management node in this instance. The operation and maintenance service it provides is specifically implemented as the control of battery power in this instance. The flow chart is as follows: Figure 8 This service will be performed when the battery voltage is less than the lower limit voltage V LWhen the robot enters the rest mode, it will be put into rest mode through the nodes of the device management layer. Specifically, it will cut off the power supply of LED lighting, servos, depth cameras, and self-organizing network modules through the power management node to minimize battery consumption and wait for the solar array to charge the battery. It should be noted that in rest mode, the robot still needs to power the electrostatic adsorption film to prevent the robot from sliding off the target spacecraft. Every once in a while, the robot will check whether the battery voltage is greater than the upper limit voltage V H If yes, the service ends, if no, the robot remains in rest mode. This service controls the battery voltage of the robot to V L ~V H In this example, V L =7V, V H =8.4V.

[0065] The communication node communicates with the master node and the management node of the ad hoc network module. It includes communication services. In this example, the communication service is divided into two parts. One is to communicate with the ground end to obtain the ground end's command to the robot; the other is to send the spacecraft surface fault detection data to the ground end.

[0066] In summary, the subtask algorithm layer communicates with the master node in the form of ROS Service and communicates with each node in the device management layer in the form of ROS Topic. The communication architecture based on ROS is as follows: Fig. 9 As shown in the figure, Client and Server represent ROSService communication. The master node calls the services represented by various Servers of the subtask algorithm layer through Client; Publisher and Subscriber represent ROSTopic communication. Publisher publishes information to a topic, and Subscriber receives information on the topic. Table 1 lists the various ROS services of the master node and the subtask algorithm layer.

[0067] Table 1 Various ROS services in the master node and subtask algorithm layer

[0068]

[0069] Table 2 lists various ROS topics in the subtask algorithm layer and the device management layer.

[0070] Table 2 Various ROS topics at the subtask algorithm layer and device management layer

[0071]

[0072]

[0073] Although the present invention has been disclosed as above in the form of a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art may make possible changes and modifications to the technical solution of the present invention by using the methods and technical contents disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the protection scope of the technical solution of the present invention.

Claims

1. A software architecture system suitable for an on-orbit service wall-climbing robot, characterized in that: The software architecture system adopts a layered architecture, which includes the following from top to bottom: The task logic layer is used to organize the overall process of the wall-climbing robot entering the on-orbit service into a safe and automated task logic, communicate with the subtask algorithm layer, and call the corresponding algorithm of the subtask algorithm layer in different states of the task logic; The subtask algorithm layer is used to store the nodes required for the wall-climbing robot to enter on-orbit service, communicate with the device management layer, obtain sensor information from each device of the robot, and send various control instructions; The device management layer is used to analyze the communication protocol between the microprocessors of each device of the on-orbit service wall-climbing robot and the robot's main control chip, realize the reading / writing of the upper-layer control node to the microprocessors of each single machine at the bottom layer, and thus realize the effective control of each device of the robot; The subtask algorithm layer includes four types of software nodes, namely: A perception planning node is used to provide a path planning service for the on-orbit service wall-climbing robot on the target spacecraft. The path planning service obtains environmental sensing information from the environmental sensor management node at the device management layer to construct a mathematical model of the environment, and uses the mathematical model to generate an optimal travel trajectory; the path planning service is called by the master node in the autonomous navigation state; Behavior nodes are used to provide services participated by various actuators of the on-orbit service wall-climbing robot. The services participated by the actuators obtain the status of various actuators of the on-orbit service wall-climbing robot from the nodes of the device management layer, and use the status of the actuators for modeling, planning and control; the services participated by the actuators are called by the master node; The operation and maintenance node is used to provide operation and maintenance services. The operation and maintenance service obtains the operation status of each device of the on-orbit service wall-climbing robot from the device management layer. If there is an operation problem, maintenance operations will be performed until the operation problem of the on-orbit service wall-climbing robot is repaired. The operation and maintenance service is called by the master node in the system operation and maintenance state; A communication node is used to provide communication services, including receiving services and sending services; the receiving service communicates with the self-organizing network module management node of the device management layer, receives data from the host computer that is also equipped with the self-organizing network module management node, and the receiving service is called by the master node in the waiting command state; the sending service communicates with the self-organizing network module management node of the device management layer, sends data to the host computer that is also equipped with the self-organizing network module management node, and the sending service is called by the master node; The device management layer includes 6 types of management nodes, namely, environmental sensor management node, target spacecraft approacher management node, motion and adsorption actuator management node, on-orbit service actuator management node, power management node, and self-organizing network module management node; each type of management node parses the communication protocol between the microprocessor carried by the corresponding equipment of the on-orbit service wall-climbing robot and the main control chip of the on-orbit service wall-climbing robot to realize the reading / writing of the underlying devices.

2. A software architecture system suitable for an on-orbit service wall-climbing robot as claimed in claim 1, characterized in that: The task logic layer only communicates with the subtask algorithm layer using TCP / IP; the communication protocol between the subtask algorithm layer and the device management layer is TCP / IP.

3. A software architecture system suitable for an on-orbit service wall-climbing robot as claimed in claim 1, characterized in that: The task logic layer includes a master node. The operation and maintenance center state machine in the master node contains 5 basic states, including: The approaching spacecraft landing state is used to describe the state in which the on-orbit service wall-climbing robot approaches the target spacecraft and lands stably when the robot has not reached the target spacecraft. The robot establishes stable adsorption with the target spacecraft and then automatically enters the waiting command state. The waiting command state is used to describe that the on-orbit service wall-climbing robot is on the target spacecraft and is on standby. It can receive external service start requests and automatically perform self-inspection and maintenance of the on-orbit service wall-climbing robot, entering the system operation and maintenance state; System operation and maintenance status is used to describe that the on-orbit service wall-climbing robot is in automatic detection and maintenance. It is divided into two sub-states: operation status detection and maintenance operation. The former detects the operation status of each device of the on-orbit service wall-climbing robot, and the latter maintains the on-orbit service wall-climbing robot equipment according to the detection results; The on-orbit service state is used to describe the on-orbit service wall-climbing robot in the process of on-orbit service. The prerequisite for entering this state is that the previous state must be the system operation and maintenance state, so as to ensure that the on-orbit service wall-climbing robot can perform on-orbit service in a good state; The autonomous navigation state is used to describe the on-orbit service wall-climbing robot in the process of autonomous navigation. The prerequisite for entering this state is that the previous state must be the system operation and maintenance state to ensure that the on-orbit service wall-climbing robot can perform autonomous navigation in a good state and arrive at the area to be served.

4. A software architecture system suitable for an on-orbit service wall-climbing robot as claimed in claim 1, characterized in that: The services provided by various actuators of the on-orbit service wall-climbing robot include: approach and landing target spacecraft services, spacecraft surface adsorption and movement services, and on-orbit services; The service in which the actuator participates obtains the status of various actuators of the on-orbit service wall-climbing robot from the target spacecraft approaching device management node, the motion and adsorption actuator management node, and the on-orbit service actuator management node of the equipment management layer, and uses the actuator status to model, plan and control the behaviors of approaching and landing the target spacecraft, adsorption movement on the spacecraft surface, and on-orbit service; The services in which the actuator participates are respectively called by the master node in the spacecraft approaching and landing states, the autonomous navigation state and the on-orbit service state.

5. A software architecture system suitable for an on-orbit service wall-climbing robot as claimed in claim 4, characterized in that: Each management node in the device management layer has the same structure.

6. An on-orbit service wall-climbing robot, characterized in that: A software architecture system as described in any one of claims 1 to 5 is adopted.

7. An on-orbit service wall-climbing robot as claimed in claim 6, characterized in that: The on-orbit service wall-climbing robot comprises: The main control chip and expansion board are used to communicate with various hardware units of the on-orbit service wall-climbing robot; The environmental sensor is used to obtain the depth map, point cloud and angular velocity of the environment, and communicate with the main control chip of the on-orbit service wall-climbing robot; The spacecraft approacher includes a tether mechanism and a drive board installed at the bottom of the on-orbit service wall-climbing robot; the tether mechanism ejects its own capture head onto the target spacecraft, allowing the on-orbit service wall-climbing robot to establish a tether connection with the target spacecraft, and then the on-orbit service wall-climbing robot approaches and lands on the target spacecraft by retracting the rope; the drive board communicates with the main control chip; The service actuator is used to enable the on-orbit service wall-climbing robot to adhere and crawl on the surface of the target spacecraft and communicate with the main control chip.

8. An on-orbit service wall-climbing robot as claimed in claim 7, characterized in that: The on-orbit service wall-climbing robot also includes: The power supply system is used to supply power to the on-orbit service wall-climbing robot equipment. The power supply system communicates with the main control chip; The self-organizing network module is used to receive information transmitted by the ground-end module and communicate with the main control chip.

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