Variable structure data bus transmission system and method for symmetrical space manipulator

Abstract

The application relates to a variable-structure data bus and an information flow transmission method of a symmetrical space mechanical arm, and the system comprises a first mechanical arm system cabin-penetrating bus, a second mechanical arm system cabin-penetrating bus, a third mechanical arm system cabin-penetrating bus and a fourth mechanical arm system cabin-penetrating bus; the cabin-penetrating buses can be interconnected through hardware interfaces; a core cabin is internally provided with a mechanical arm operating table; the mechanical arm operating table is provided with double BC interfaces, one of which is connected with the first mechanical arm system cabin-penetrating bus, and the other is connected with the second mechanical arm system cabin-penetrating bus; the mechanical arm operating table is connected with the mechanical arm end effector of a large arm and the internal bus of the large arm through a large arm adapter or a large arm base for communication, and is connected with the end effector of a small arm and the internal bus of the small arm through a small arm adapter or a small arm base for communication.

Description

Technical Field

[0001] This invention relates to a variable structure data bus and information flow transmission method for a symmetrical space robot, which is particularly suitable for symmetrical space robots to crawl and change positions on track. Background Technology

[0002] The robotic arm on the space station, part of the third phase of the manned space station, is responsible for tasks such as module transfer and docking, capture and assisted docking of hovering spacecraft, supporting extravehicular activities (EVAs), handling and inspecting extravehicular cargo, caring for experimental payloads on exposed platforms, and caring for optical platforms. For example... Figure 1 As shown, the space station is equipped with two robotic arms: one large arm (10-meter reach) for the core module and one small arm (5-meter reach) for the experimental module. These two robotic arms can operate independently, collaboratively, or in series at different locations within different modules of the space station. Both the large and small arms employ a 7-DOF (DoF) robotic arm design, consisting of 7 joints, 2 end effectors, 2 levers, 1 central controller, and 1 vision camera system. All joints are rotary joints, using a "3 shoulder + 1 elbow + 3 wrist" configuration. To meet the needs of the robotic arms operating at different locations on the space station, two end effectors are installed on two joints at the beginning and end of the robotic arm, respectively. The end effectors alternately connect to the "crawling" motion of the module, enabling the robotic arm to move across the space station surface. An "adapter" provides electrical, information, and mechanical interfaces for connecting the robotic arm's end effector to the module at different locations.

[0003] The end effectors also function to grasp payloads, astronauts, and modules. Both end effectors are equipped with end-effector cameras capable of target identification and attitude measurement, while monitoring cameras are mounted on the elbows or arms. A central controller at the elbow serves as the core of the robotic arm's control system and integrates a network switch for centralized transmission of video signals from the cameras on the robotic arm. The robotic arm as a whole adopts a modular design; the hardware of each joint, end effector, and end camera is identical. When the two ends are connected to the modules, the robotic arm's functions, configuration, and reach are all the same—a symmetrical design.

[0004] The space station is equipped with a robotic arm control panel, which provides an interface and handles for astronauts to operate the robotic arm. It also serves as the top-level information management device for the robotic arm system and is the hub for information exchange with other systems such as data management, GNC, instruments, and telemetry and control.

[0005] my country's manned spaceflight docking bus system can meet the information flow transmission needs of the combined spacecraft after docking with the space station. After docking is completed and the combined flight status is established, the combined flight is primarily driven by the target spacecraft, with ground control tracking and telemetry. The two spacecraft are connected via a wired docking bus, and the bidirectional information transmission content is mainly selected and transmitted by the data management subsystem. Its bus topology is as follows: Figure 2 .

[0006] The bus system of my country's third-phase lunar sample return mission is adapted to flight missions involving multi-module spacecraft requiring multiple separations. For each separation, a set of bus selectors is designed, and the modules do not reassemble after separation. Its bus topology is as follows: Figure 3 .

[0007] If the robotic arm system still uses Figure 2 , Figure 3 The design scheme still has the following bottlenecks:

[0008] 1. The data bus hierarchy of the space station robotic arm system, if adopted Figure 2 or Figure 3 The secondary bus is no longer sufficient to meet the task requirements.

[0009] 2. The bus topology for the robotic arm to complete tasks on the space station cannot meet the requirements of the two bus topologies mentioned above. Figure 2 The topology is suitable for docking tasks with independent bus interfaces and is equipped with dedicated data converters. If similar bus interfaces are set up in different locations on the space station, multiple data converters and corresponding bus gating switches are required, resulting in large hardware overhead and data converters experiencing data processing delays. Figure 3 This topology is suitable for separation actions of compartments managed by multiple independent top-level computers (BCs). Each separation is set with a separate switch. After separation, some functions of the compartment are no longer used. It is a one-time action and is not suitable for tasks where the robotic arm frequently changes position on the compartment.

[0010] 3. Using bus selector switches to perform frequent bus switching operations increases the number of unreliable components. Currently, bus selector switch products in my country's aerospace field lack direct telemetry, making it impossible for ground personnel to visually determine whether the switching is normal. Furthermore, frequent switch operation also poses a risk of failure. Figure 2 , 3 Each bus gating switch used for bus topology transformation only operates once during the task. However, for frequent actions such as the robotic arm's "crawling" position changes, as well as the series connection and separation of the large and small arms, bus gating switches should be used as little as possible or not at all.

[0011] 4. The 1553B data bus length constraint: In the bus system design, if the main line is longer than 100 meters and the branch line is longer than 6 meters, the bus transmission signal will be greatly attenuated without using a bus repeater. However, the cable network lengths of each module in the space station system are only tens of meters, and the robotic arm can be connected to the adapters in each module. Furthermore, the reach of the robotic arm has reached 10 meters. Given these constraints, a separate bus topology design is required, minimizing the use of bus repeaters (as this increases latency, hardware costs, and reliability).

[0012] Therefore, the bus systems mentioned above, which are suitable for docking or separating spacecraft and the hierarchical data bus systems of conventional spacecraft, can no longer meet the mission requirements of the space station robotic arm. Summary of the Invention

[0013] The technical problem solved by this invention is to overcome the shortcomings of the prior art and provide a variable structure data bus transmission system for a symmetrical space robotic arm, which meets the real-time requirements of the control system for information transmission and is suitable for tasks such as on-orbit crawling and combination of space robotic arms with changing topologies.

[0014] The solution of this invention is: a variable structure data bus transmission system for a symmetrical space robotic arm. The symmetrical space robotic arm includes two sets of robotic arms, referred to as the upper arm and the lower arm, respectively. Both the upper arm and the lower arm include two end effectors, which are respectively installed on the joints at the beginning and end of the robotic arm. The bus transmission system includes a robotic arm through-cabin bus, an inner bus for the upper arm, and an inner bus for the lower arm. The robotic arm through-cabin bus includes a first robotic arm system through-cabin bus, a second robotic arm system through-cabin bus, a third robotic arm system through-cabin bus, and a fourth robotic arm system through-cabin bus.

[0015] The first and second robotic arm systems' cabin-penetrating bus is located in the core module; the third robotic arm system's cabin-penetrating bus is located in the first experimental module; and the fourth robotic arm system's cabin-penetrating bus is located in the second experimental module.

[0016] The first robotic arm system's through-cabin bus and / or the second robotic arm system's through-cabin bus connect to the boom adapter or boom base; the boom adapter or boom base is used to connect to the boom end effector.

[0017] The third robotic arm system's through-cabin bus and / or the fourth robotic arm system's through-cabin bus connect the boom adapter, boom base, forearm adapter, or forearm base; the forearm adapter or forearm base is used to connect the forearm end effector.

[0018] When the first experimental module docks with the core module, the third robotic arm system's through-cabin bus can interconnect with the first robotic arm system's through-cabin bus or the second robotic arm system's through-cabin bus via a hardware interface.

[0019] When the second experimental module docks with the core module, the fourth robotic arm system's through-cabin bus can be interconnected with the first robotic arm system's through-cabin bus or the second robotic arm system's through-cabin bus via a hardware interface.

[0020] The core module is equipped with a robotic arm control panel. The robotic arm control panel has dual BC interfaces. One BC interface is connected to the first robotic arm system's through-cabin bus, and the other BC interface is connected to the second robotic arm system's through-cabin bus. The robotic arm control panel, as the BC, communicates with the robotic arm's end effector and the inner bus of the upper arm through the upper arm adapter or upper arm base. It also communicates with the inner bus of the lower arm through the lower arm's end effector and the lower arm's inner bus through the lower arm adapter or lower arm base.

[0021] Preferably, the variable structure data bus transmission system of the above-mentioned symmetrical space robotic arm further includes a first experimental module wall connector, a second experimental module wall connector, a first experimental module docking assembly, a second experimental module docking assembly, a third experimental module docking assembly, a core module first wall connector, a core module second wall connector, a core module third wall connector, a first bus selector switch, a second bus selector switch, a third bus selector switch, a fourth bus selector switch, and a fifth bus selector switch. Each bus selector switch is a two-to-one switch, including a switch control terminal, a first branch, a second branch, and a combined branch. The first branch is connected to the combined branch or the second branch is connected to the combined branch through the switch control terminal.

[0022] The first experimental module docking assembly is connected to the third robotic arm system through the cabin bus via the first experimental module bulkhead connector. The first experimental module docking assembly is also used to connect to the first bulkhead connector of the core module.

[0023] The second experimental module docking assembly is connected to the fourth robotic arm system via the second experimental module bulkhead connector; the second experimental module docking assembly is also used to connect to the core module second bulkhead connector.

[0024] The third experimental module docking assembly is used to connect with the third bulkhead connector of the core module.

[0025] Both the first and second experimental modules can dock with the core module via the docking components of the third experimental module.

[0026] The composite branch of the first bus gating switch is connected to the third bulkhead connector of the core module, the first branch is connected to the second branch of the second bus gating switch, and the second branch is connected to the first branch of the third bus gating switch.

[0027] The first branch of the second bus selector switch is connected to the first bulkhead connector of the core module, the combined branch is connected to the second branch of the fourth bus selector switch, the first branch of the fourth bus selector switch is connected to the load, and the combined branch is connected to the second robotic arm system through-cabin bus.

[0028] The second branch of the third bus selector switch is connected to the second bulkhead connector of the core module, the composite branch is connected to the first branch of the fifth bus selector switch, the second branch of the fifth bus selector switch is connected to the load, and the composite branch is connected to the first robotic arm system's through-cabin bus.

[0029] Preferably, the two end effectors of the boom and forearm can be connected to an adapter or base on the surface of the cabin at one end, or both can be connected to different adapters or bases on the surface of the cabin. The two end effectors of the boom and forearm can perform a "crawling" action of alternating connection to the cabin in the form of "single-end connection-double-end connection-single-end connection", so as to realize the position transfer of the robotic arm on the surface of the space station.

[0030] Preferably, both the upper arm and the lower arm include two end effectors, a central controller, a joint controller, a monitoring camera, and an Ethernet switch. The central controller and the end effectors, joint controllers, and Ethernet switches are in a BC and RT relationship. The end effectors of the upper arm and the lower arm are also equipped with end cameras for target identification and pose measurement, which are also connected to the robot arm's internal bus via RT. The upper arm and the lower arm are also equipped with monitoring cameras, which are also connected to the robot arm's internal bus via RT.

[0031] Preferably, only one of the two end effector controllers of the robotic arm communicates with the robotic arm control panel at any given time. The end effector containing this end effector is denoted as the fixed end effector. The other end effector does not communicate with the robotic arm control panel, and the end effector containing this fixed end effector is denoted as the free end effector. The fixed end effector is used to facilitate communication between the robotic arm control panel inside the transfer compartment and the central controller inside the robotic arm, specifically as follows:

[0032] The robotic arm control panel determines whether the robotic arm's end controllers are online by polling the online status of the two end controllers of the robotic arm. The end controller that is online first is selected as the fixed end controller. If this end controller is always online or there is no other end controller online when it is offline, the end actuator corresponding to this end controller is selected as the fixed end controller. If this end controller is offline and the other end controller is online, the end actuator corresponding to the other end controller is selected as the fixed end controller.

[0033] The terminal controller of the fixed terminal sets the "communication status with the console controller" in the preset sub-address message to "communicating with the console"; the terminal controller of the free terminal sets the "communication status with the console controller" in the preset sub-address message to "not communicating with the console".

[0034] The central controller inside the robotic arm determines the fixed end effector by querying the "communication status with the console controller" in the preset sub-address information of the end effector corresponding to the end effector.

[0035] Preferably, when the robotic arm operating console sends data to the large arm central controller, in the robotic arm system's through-cabin bus, the robotic arm operating console, acting as the BC, communicates with the fixed end, which acts as the RT. The fixed end moves the data sent by the robotic arm operating console to the address space agreed upon by the large arm internal bus system. In the large arm internal bus system, the large arm central controller, acting as the BC, reads the data from the fixed end, which acts as the RT.

[0036] When the central controller of the boom sends data to the robotic arm operating table, in the boom intrabus system, the central controller of the boom, acting as the BC, communicates with the fixed end, which acts as the RT. The fixed end moves the data sent by the central controller to the address space agreed upon by the robotic arm system through-cabin bus. In the robotic arm system through-cabin bus, the robotic arm operating table, acting as the BC, communicates with the fixed end, which acts as the RT.

[0037] Preferably, the information flow of the robotic arm operating console sending data to the upper arm joint is as follows: In the robotic arm through-cabin bus, the robotic arm operating console, as BC, communicates with the fixed end, which is the RT. The fixed end moves the content of the communication with the robotic arm operating console to the address space agreed upon by the upper arm internal bus. In the upper arm internal bus, the upper arm central controller, as BC, collects the data moved by the fixed end, and sends it to the upper arm joint, which is the RT, after address judgment.

[0038] Conversely, in the inner bus of the boom, the central controller of the boom, acting as the BC, communicates with the boom joint, which acts as the RT, and forwards the content sent by the boom joint to the robotic arm operating console to the fixed end effector. The fixed end effector moves the content sent by the boom joint to the robotic arm operating console to a preset address space. In the robotic arm through-cabin bus, the robotic arm operating console, acting as the BC, queries the fixed end effector, which acts as the RT, to read the data.

[0039] Preferably, after the forearm end effector is connected to the robotic arm's through-cabin bus via an adapter or forearm base, the branch lines of the robotic arm's through-cabin bus run through the forearm arm to the forearm central controller; the information flow of the robotic arm control console controlling the forearm is as follows:

[0040] In the robotic arm through-cabin bus, the robotic arm control panel, acting as the BC, communicates with the forearm central controller, which acts as the RT; in the forearm intra-bus, the forearm central controller, acting as the BC, communicates with the forearm joint.

[0041] The aforementioned symmetrical space robotic arm's variable structure data bus transmission system also includes a dual-arm combined adapter suspension device, which serves as the RT access to the robotic arm's through-cabin bus. This dual-arm combined adapter suspension device is used to carry the "adapter," which can be grasped or released by the upper arm or lower arm to connect the upper arm and lower arm in series, ensuring mechanical, power supply, and information connectivity between the upper arm and lower arm.

[0042] When the boom and forearm work independently on the cabin, the "adapter" is placed on this "suspension device"; when the boom and forearm need to form a series combination, the "suspension device" releases the "adapter" to be handed over to the free end of the boom for gripping, and the free end of the forearm then grips the forearm adapter interface of the adapter carried on the end of the boom, thus realizing the series connection of the two booms.

[0043] When the boom and forearm are connected in series, the free end of the boom switches to the BC in the boom-forearm combined bus system to communicate with the central controller of the forearm. Its data communication protocol is consistent with the communication protocol when the forearm works alone and is directly connected to the control panel inside the cabin. The boom, as a whole, transparently transmits telemetry and remote control data between the forearm and the robotic arm control panel. The bus cables connecting the boom and forearm are laid in the adapter that provides mechanical connection between the boom and forearm.

[0044] Another technical solution of the present invention is: a variable structure data bus transmission method for a symmetrical space robotic arm, including an information control method during the "crawling" motion process in which the two end effectors of the upper or lower arm alternately connect to the cabin via "single-end connection-double-end connection-single-end connection", as detailed below:

[0045] S1. Power on the robotic arm control panel, the first end effector, the central controller, and the second end effector in that order.

[0046] S2. The robotic arm control panel detects the online end effector and determines that the first end effector is a fixed end effector, communicating with the main arm through the online first end effector. At the same time, the end effector of the first end effector acts as the RT on the robotic arm system's through-cabin bus. After detecting that the robotic arm control panel BC is communicating with it, it makes a communication mark on a specific data address in the main arm bus, that is, sets the "communication status with control panel controller" in the preset sub-address message to "communicating with control panel". The first end effector also acts as the RT on the main arm's internal bus, preparing status data on this bus, waiting for the periodic acquisition by the main arm central controller BC. The second end effector is a free end effector, and sets the "communication status with control panel controller" in the preset sub-address message to "not communicating with control panel".

[0047] S4. The central controller of the boom determines that the "communication status with the operator console controller" of the first end is "communicating with the operator console". It establishes communication with the first end, thus ensuring that the information routing of the BC devices in the two sets of buses all pass through the first end, and the information path of each device is fully open.

[0048] S5. The robotic arm moves and grabs the robotic arm adapter or base under the control of the ground or astronaut. The second end effector bus branch is connected to the adapter. The robotic arm control panel determines that the first end is always online and still chooses to communicate with the main arm through the first end, without communicating with the second end. The communication flag of the first end, "Communication status with control panel controller", remains unchanged as "Communicating with control panel". The communication status of the internal bus of the robotic arm does not change. The information routing of the BC devices in the two sets of buses is still through the first end, and the information paths of each device are fully open.

[0049] S6. With both ends of the robotic arm gripping the cabin adapter, power off the entire arm in the following order: second end, central controller, and first end.

[0050] S7. With the dual-end connected cabin in the state, power on via the new adapter, in the order of the second end, central controller, and first end;

[0051] S8. The robotic arm control panel first determines that the second end effector is online and selects the second end effector to communicate with the main arm. After the second end effector detects that the control panel is communicating with itself, it makes a communication mark on the corresponding data address in the main arm bus, that is, it sets the "communication status with control panel controller" in a specific data bit to "communicating with control panel". After the main arm central controller determines this mark, it also establishes communication with the second end effector, ensuring that the information routing of BC devices in the two sets of buses all pass through the second end effector and the information path of each device is fully open; the first end effector is a free end effector, and sets the "communication status with control panel controller" in the preset sub-address message to "not communicating with control panel".

[0052] S9. The ground or astronaut controls the first end to release the base and control the robotic arm to move away from the base. The first end bus branch is disconnected from the "robotic arm system through-cabin bus". The control panel determines that the second end is always online and still selects the second end to communicate with the main arm. The communication mark of the second end does not change. The communication status of the main arm's internal bus does not change. All information channels of each device are open.

[0053] S10. Repeat steps S5 to S9 above to maintain communication while the robotic arm continues to "crawl" to other adapters.

[0054] The advantages of this invention compared to the prior art are:

[0055] (1) Compared with the existing design, the present invention uses a simple bus system and a combination of bus gating switches. The bus hierarchy is clear and independent of each other, which meets the real-time requirements of the control system for information transmission and is suitable for tasks such as on-track crawling and combination of space robotic arms with changing topologies.

[0056] (2) The present invention utilizes the dual BC interface design of the robotic arm operating table to solve the problems of large spacecraft compartment volume and excessively long main line, and avoids the design of adding bus repeaters.

[0057] (3) The dual RT interface at the end of the arm of the present invention meets the bus connection requirements and avoids the hardware cost of increasing bus repeaters due to excessively long branch lines.

[0058] (4) The design of the bus selection switch combination of the present invention meets the requirements of single-cabin, two-cabin straight configuration, three-cabin T-shaped configuration, and forward docking of visiting aircraft. Attached Figure Description

[0059] Figure 1 This is a schematic diagram of the upper arm and lower arm of the space station according to an embodiment of the present invention.

[0060] Figure 2 This is a schematic diagram of the data bus system of a conventional docking assembly according to an embodiment of the present invention.

[0061] Figure 3 This is a schematic diagram of a conventional detector data bus system according to an embodiment of the present invention.

[0062] Figure 4 This is a schematic diagram of the space station robotic arm system's through-cabin bus according to an embodiment of the present invention.

[0063] Figure 5 This is a schematic diagram of the internal bus of the robotic arm and the combined bus of the large and small arms in an embodiment of the present invention.

[0064] Figure 6 This is the logic for the robotic arm's main arm to autonomously determine the connection to the fixed end of the cabin in an embodiment of the present invention.

[0065] Figure 7 This is the logic for the operator console to autonomously determine the fixed end of the communication in an embodiment of the present invention.

[0066] Figure 8 This is a schematic diagram of the bus selection switch in an embodiment of the present invention. Detailed Implementation

[0067] The present invention will be further described below with reference to the embodiments.

[0068] This invention provides a variable structure data bus transmission system for a symmetrical space robotic arm. In this system, the symmetrical space robotic arm comprises two robotic arms, referred to as the upper arm and the lower arm. Both the upper arm and the lower arm include two end effectors, which are respectively mounted on the joints at the beginning and end of the robotic arm. The bus transmission system includes a robotic arm through-cabin bus, an inner bus for the upper arm, and an inner bus for the lower arm. The robotic arm through-cabin bus includes a first robotic arm system through-cabin bus, a second robotic arm system through-cabin bus, a third robotic arm system through-cabin bus, and a fourth robotic arm system through-cabin bus.

[0069] The first and second robotic arm systems' cabin-penetrating bus is located in the core module; the third robotic arm system's cabin-penetrating bus is located in the first experimental module; and the fourth robotic arm system's cabin-penetrating bus is located in the second experimental module.

[0070] The first robotic arm system's through-cabin bus and / or the second robotic arm system's through-cabin bus connect to the boom adapter or boom base; the boom adapter or boom base is used to connect to the boom end effector.

[0071] The third robotic arm system's through-cabin bus and / or the fourth robotic arm system's through-cabin bus connect the boom adapter, boom base, forearm adapter, or forearm base; the forearm adapter or forearm base is used to connect the forearm end effector.

[0072] When the first experimental module docks with the core module, the third robotic arm system's through-cabin bus can interconnect with the first robotic arm system's through-cabin bus or the second robotic arm system's through-cabin bus via a hardware interface.

[0073] When the second experimental module docks with the core module, the fourth robotic arm system's through-cabin bus can be interconnected with the first robotic arm system's through-cabin bus or the second robotic arm system's through-cabin bus via a hardware interface.

[0074] The core module is equipped with a robotic arm control panel. The robotic arm control panel has dual BC interfaces. One BC interface is connected to the first robotic arm system's through-cabin bus, and the other BC interface is connected to the second robotic arm system's through-cabin bus. The robotic arm control panel, as the BC, communicates with the robotic arm's end effector and the inner bus of the upper arm through the upper arm adapter or upper arm base. It also communicates with the inner bus of the lower arm through the lower arm's end effector and the lower arm's inner bus through the lower arm adapter or lower arm base.

[0075] like Figure 2As shown, the variable structure data bus transmission system of the aforementioned symmetrical space robotic arm includes a first experimental module wall connector, a second experimental module wall connector, a first experimental module docking assembly, a second experimental module docking assembly, a third experimental module docking assembly, a core module first wall connector, a core module second wall connector, a core module third wall connector, a first bus selector switch, a second bus selector switch, a third bus selector switch, a fourth bus selector switch, and a fifth bus selector switch. Each bus selector switch is a two-to-one switch, including a switch control terminal, a first branch, a second branch, and a combined branch. The first branch is connected to the combined branch or the second branch is connected to the combined branch through the switch control terminal.

[0076] The first experimental module docking assembly is connected to the third robotic arm system through the cabin bus via the first experimental module bulkhead connector. The first experimental module docking assembly is also used to connect to the first bulkhead connector of the core module.

[0077] The second experimental module docking assembly is connected to the fourth robotic arm system via the second experimental module bulkhead connector; the second experimental module docking assembly is also used to connect to the core module second bulkhead connector.

[0078] The third experimental module docking assembly is used to connect with the third bulkhead connector of the core module.

[0079] Both the first and second experimental modules can dock with the core module via the docking components of the third experimental module.

[0080] The composite branch of the first bus gating switch is connected to the third bulkhead connector of the core module, the first branch is connected to the second branch of the second bus gating switch, and the second branch is connected to the first branch of the third bus gating switch.

[0081] The first branch of the second bus selector switch is connected to the first bulkhead connector of the core module, the combined branch is connected to the second branch of the fourth bus selector switch, the first branch of the fourth bus selector switch is connected to the load, and the combined branch is connected to the second robotic arm system through-cabin bus.

[0082] The second branch of the third bus selector switch is connected to the second bulkhead connector of the core module, the composite branch is connected to the first branch of the fifth bus selector switch, the second branch of the fifth bus selector switch is connected to the load, and the composite branch is connected to the first robotic arm system's through-cabin bus.

[0083] Preferably, the two end effectors of the boom and forearm can be connected to an adapter or base on the surface of the cabin at one end, or both can be connected to different adapters or bases on the surface of the cabin. The two end effectors of the boom and forearm can perform a "crawling" action of alternating connection to the cabin in the form of "single-end connection-double-end connection-single-end connection", so as to realize the position transfer of the robotic arm on the surface of the space station.

[0084] Preferably, both the upper arm and the lower arm include two end effectors, a central controller, a joint controller, a monitoring camera, and an Ethernet switch. The central controller and the end effectors, joint controllers, and Ethernet switches are in a BC and RT relationship. The end effectors of the upper arm and the lower arm are also equipped with end cameras for target identification and pose measurement, which are also connected to the robot arm's internal bus via RT. The upper arm and the lower arm are also equipped with monitoring cameras, which are also connected to the robot arm's internal bus via RT.

[0085] Preferably, only one of the two end effector controllers of the robotic arm communicates with the robotic arm control panel at any given time. The end effector containing this end effector is denoted as the fixed end effector. The other end effector does not communicate with the robotic arm control panel, and the end effector containing this fixed end effector is denoted as the free end effector. The fixed end effector is used to facilitate communication between the robotic arm control panel inside the transfer compartment and the central controller inside the robotic arm, specifically as follows:

[0086] The robotic arm control panel determines whether the robotic arm's end controllers are online by polling the online status of the two end controllers of the robotic arm. The end controller that is online first is selected as the fixed end controller. If this end controller is always online or there is no other end controller online when it is offline, the end actuator corresponding to this end controller is selected as the fixed end controller. If this end controller is offline and the other end controller is online, the end actuator corresponding to the other end controller is selected as the fixed end controller.

[0087] The terminal controller of the fixed terminal sets the "communication status with the console controller" in the preset sub-address message to "communicating with the console"; the terminal controller of the free terminal sets the "communication status with the console controller" in the preset sub-address message to "not communicating with the console".

[0088] The central controller inside the robotic arm determines the fixed end effector by querying the "communication status with the console controller" in the preset sub-address information of the end effector corresponding to the end effector.

[0089] Preferably, when the robotic arm operating console sends data to the large arm central controller, in the robotic arm system's through-cabin bus, the robotic arm operating console, acting as the BC, communicates with the fixed end, which acts as the RT. The fixed end moves the data sent by the robotic arm operating console to the address space agreed upon by the large arm internal bus system. In the large arm internal bus system, the large arm central controller, acting as the BC, reads the data from the fixed end, which acts as the RT.

[0090] When the central controller of the boom sends data to the robotic arm operating table, in the boom intrabus system, the central controller of the boom, acting as the BC, communicates with the fixed end, which acts as the RT. The fixed end moves the data sent by the central controller to the address space agreed upon by the robotic arm system through-cabin bus. In the robotic arm system through-cabin bus, the robotic arm operating table, acting as the BC, communicates with the fixed end, which acts as the RT.

[0091] Preferably, the information flow of the robotic arm operating console sending data to the upper arm joint is as follows: In the robotic arm through-cabin bus, the robotic arm operating console, as BC, communicates with the fixed end, which is the RT. The fixed end moves the content of the communication with the robotic arm operating console to the address space agreed upon by the upper arm internal bus. In the upper arm internal bus, the upper arm central controller, as BC, collects the data moved by the fixed end, and sends it to the upper arm joint, which is the RT, after address judgment.

[0092] Conversely, in the inner bus of the boom, the central controller of the boom, acting as the BC, communicates with the boom joint, which acts as the RT, and forwards the content sent by the boom joint to the robotic arm operating console to the fixed end effector. The fixed end effector moves the content sent by the boom joint to the robotic arm operating console to a preset address space. In the robotic arm through-cabin bus, the robotic arm operating console, acting as the BC, queries the fixed end effector, which acts as the RT, to read the data.

[0093] Preferably, after the forearm end effector is connected to the robotic arm's through-cabin bus via an adapter or forearm base, the branch lines of the robotic arm's through-cabin bus run through the forearm arm to the forearm central controller; the information flow of the robotic arm control console controlling the forearm is as follows:

[0094] In the robotic arm through-cabin bus, the robotic arm control panel, acting as the BC, communicates with the forearm central controller, which acts as the RT; in the forearm intra-bus, the forearm central controller, acting as the BC, communicates with the forearm joint.

[0095] The aforementioned symmetrical space robotic arm's variable structure data bus transmission system also includes a dual-arm combined adapter suspension device, which serves as the RT access to the robotic arm's through-cabin bus. This dual-arm combined adapter suspension device is used to carry the "adapter," which can be grasped or released by the upper arm or lower arm to connect the upper arm and lower arm in series, ensuring mechanical, power supply, and information connectivity between the upper arm and lower arm.

[0096] When the boom and forearm work independently on the cabin, the "adapter" is placed on this "suspension device"; when the boom and forearm need to form a series combination, the "suspension device" releases the "adapter" to be handed over to the free end of the boom for gripping, and the free end of the forearm then grips the forearm adapter interface of the adapter carried on the end of the boom, thus realizing the series connection of the two booms.

[0097] When the boom and forearm are connected in series, the free end of the boom switches to the BC in the boom-forearm combined bus system to communicate with the central controller of the forearm. Its data communication protocol is consistent with the communication protocol when the forearm works alone and is directly connected to the control panel inside the cabin. The boom, as a whole, transparently transmits telemetry and remote control data between the forearm and the robotic arm control panel. The bus cables connecting the boom and forearm are laid in the adapter that provides mechanical connection between the boom and forearm.

[0098] The variable structure data bus transmission method for the symmetrical space robotic arm of the above system includes an information control method during the "crawling" motion process in which the two end effectors of the upper or lower arm alternately connect to the cabin via "single-end connection-double-end connection-single-end connection," as detailed below:

[0099] S1. Power on the robotic arm control panel, the first end effector, the central controller, and the second end effector in that order.

[0100] S2. The robotic arm control panel detects the online end effector and determines that the first end effector is a fixed end effector, communicating with the main arm through the online first end effector. At the same time, the end effector of the first end effector acts as the RT on the robotic arm system's through-cabin bus. After detecting that the robotic arm control panel BC is communicating with it, it makes a communication mark on a specific data address in the main arm bus, that is, sets the "communication status with control panel controller" in the preset sub-address message to "communicating with control panel". The first end effector also acts as the RT on the main arm's internal bus, preparing status data on this bus, waiting for the periodic acquisition by the main arm central controller BC. The second end effector is a free end effector, and sets the "communication status with control panel controller" in the preset sub-address message to "not communicating with control panel".

[0101] S4. The central controller of the boom determines that the "communication status with the operator console controller" of the first end is "communicating with the operator console". It establishes communication with the first end, thus ensuring that the information routing of the BC devices in the two sets of buses all pass through the first end, and the information path of each device is fully open.

[0102] S5. The robotic arm moves and grabs the robotic arm adapter or base under the control of the ground or astronaut. The second end effector bus branch is connected to the adapter. The robotic arm control panel determines that the first end is always online and still chooses to communicate with the main arm through the first end, without communicating with the second end. The communication flag of the first end, "Communication status with control panel controller", remains unchanged as "Communicating with control panel". The communication status of the internal bus of the robotic arm does not change. The information routing of the BC devices in the two sets of buses is still through the first end, and the information paths of each device are fully open.

[0103] S6. With both ends of the robotic arm gripping the cabin adapter, power off the entire arm in the following order: second end, central controller, and first end.

[0104] S7. With the dual-end connected cabin in the state, power on via the new adapter, in the order of the second end, central controller, and first end;

[0105] S8. The robotic arm control panel first determines that the second end effector is online and selects the second end effector to communicate with the main arm. After the second end effector detects that the control panel is communicating with itself, it sets the communication mark "Communication status with control panel controller" to "Communicating with control panel" on the corresponding data address in the main arm bus. After the main arm central controller detects this mark, it also establishes communication with the second end effector, ensuring that the information routing of the BC devices in the two sets of buses all pass through the second end effector, and the information path of each device is fully open. The first end effector is a free end effector and sets the "Communication status with control panel controller" in the preset sub-address message to "Not communicating with control panel".

[0106] S9. The ground or astronaut controls the first end to release the base and control the robotic arm to move away from the base. The first end bus branch is disconnected from the "robotic arm system through-cabin bus". The control panel determines that the second end is always online and still selects the second end to communicate with the main arm. The communication mark of the second end does not change. The communication status of the main arm's internal bus does not change. All information channels of each device are open.

[0107] S10. Repeat steps S5 to S9 above to maintain communication while the robotic arm continues to "crawl" to other adapters.

[0108] Regardless of the location of the robotic arm, this invention allows communication between the robotic arm and the control panel inside the cabin via a specific end effector (specific, meaning a choice between two end effectors, which can be determined autonomously by software or forcibly specified by ground personnel). Adapters at different locations on the cabin surface enable the communication interface (1553B branch line) between the external robotic arm and the internal control panel for through-path connection.

[0109] Example:

[0110] Within the entire arm system, the relationship between the central controller and the joints and end effectors is that of a controller and an actuator. The closed-loop control has high real-time requirements and should be designed as a BC to RT relationship with a relatively independent bus system. The operator console is located inside the space station cabin and serves as the information management system for the robotic arm system. It should act as the BC for both robotic arms. The data management unit (KPU) serves as the top-level information management system of the space station and should act as the BC for the operator console. When the large and small arms are combined, it is necessary to ensure communication between the two robotic arms and the operator console, and also to allow the two to exchange information with each other.

[0111] In a specific embodiment of the present invention, the following is employed: Figure 4 , Figure 5 The bus system, the topology adapted to the robotic arm's tasks and the ways in which the topology changes, and Figure 6 , Figure 7 The judgment logic used by each BC in the middle realizes the effective transmission of information flow.

[0112] The space station robotic arm's bus system includes: a cross-module bus, an intra-module bus (one set each for the large and small arms), and a combined large and small arm bus, totaling four bus systems and five bus selector switches. This system meets various mission requirements, such as the large and small arms "crawling" and switching positions in different modules, dual-arm combination, and collaborative work. The bus selector switches involved are activated only once in their respective missions.

[0113] The robotic arm system uses a cross-cabin bus. The robotic arm control panel, acting as a BC (dual BC with consistent software design), connects to the robotic arm's end effector via an adapter to communicate with the main arm and forearm. It also exchanges data with onboard auxiliary equipment such as the docking camera and suspension system. Figure 4 The robotic arm operates at various positions in each module under different module combinations during the entire mission phase of the space station, through the switching combination of 5 sets of bus selector switches.

[0114] The robotic arm's internal bus, with the central controller acting as the BC (Browser / Controller), interacts with other robotic arm devices on this bus, such as control controllers, end effector controllers, cameras, and switches. Figure 5 .

[0115] The bus branch interface extends through the arm to the two ends of the forearm. The two interfaces are set to different RTs. The 1553B bus system itself has hardware constraints. Communication is stable within 100m of the main line and 6m of the branch line. If the main line or branch line is too long, it may cause signal attenuation and communication abnormalities. The design of the main line has the constraint of being less than 100m in length, and it must also meet the layout of connecting the robotic arm adapters in various parts of the three modules. (The total length of a module of the space station is tens of meters. Considering the cable routing, if a single main line is used to connect the adapters of the robotic arm in all three modules, it is extremely easy for the main line to be too long and the signal to be attenuated.) Therefore, the robotic arm through-module bus is divided into two sections (two sets of 1553B systems). The robotic arm operating console is designed as a dual BC device, which can serve as the BC of the two 1553B bus systems. That is, buses 1 and 4 are connected in series to form one system, and buses 2 and 3 are connected in series to form another system. The two bus systems are controlled by the robotic arm operating console.

[0116] The branch line design primarily considers the wiring constraints caused by the reach of the robotic arm. The maximum reach of the extended arm is 10m, and the maximum reach of the extended arm is 5m. Due to the symmetrical design, the central controllers for both arms are located at the elbow joint, approximately at the midpoint when the robotic arm is at its maximum reach. (Regardless of which end unit connects to the cabin, the cable distance from the central controller to the end unit is basically the same: approximately 5m from the extended arm central controller to the extended arm end unit, and approximately 2.5m from the extended arm central controller to the extended arm end unit.) The 2.5m for the extended arm is less than the 6m branch line constraint, leaving room for cable routing. Connecting the extended arm central controller as an RT directly to the main bus inside the cabin via an adapter branch line satisfies the communication constraint. However, the extended arm's 5m is close to the 6m branch line constraint. Directly connecting the central controller as an RT to the cabin bus would not meet the 6m branch line constraint due to cable routing limitations. Therefore, communication between the extended arm central controller and the robotic arm control panel requires an end effector as an intermediary device.

[0117] Since the boom span is 10 meters, if a tree-like bus structure of BC-RT is used from the robotic arm operator console to the central controller, there will be a problem of excessively long branch lines. Therefore, it is necessary to transfer the communication between the robotic arm operator console and the central controller through the end of the cabin, i.e., the BC-RT-BC mode.

[0118] Because the robotic arm "crawls" on the space station, the central controller needs to transmit information to the robotic arm's control panel inside the spacecraft via the end effector connected to the module. This is achieved by the end effector grasping the identifier of the robotic arm adapter or base, and by comprehensively determining the position of the fixed end effector (first or second end effector) connected to the module and the robotic arm's position on the module. The determined fixed end effector then routes the information flow for robotic arm telemetry and remote control. The identified adapter number is used to identify the robotic arm's own position for subsequent mission planning. The judgment logic is as follows: Figure 6 .

[0119] The robotic arm's internal bus (forearm) uses a central controller (BC) to interact with other robotic arm devices such as joint controllers, end effectors, cameras, and switches. Since the forearm has a 5-meter reach, the BC-RT tree-structured bus avoids excessively long branch lines. The forearm central controller can communicate directly with the robotic arm's control panel. Its bus branch interfaces extend through the arm to the two end effectors of the forearm, with each interface configured as a different RT. The central controller can determine which end effector (RT) is connected to the control panel based on its communication with the control panel, and then identify its own position using the identified adapter number for subsequent task planning. This decision logic is reusable. Figure 6 .

[0120] Therefore, the bus topology of the two arms ( Figure 5 The design is slightly different.

[0121] Example 1: Information flow of the robotic arm control panel for forearm: robotic arm control panel BC → RT forearm central controller BC → RT forearm joint; (where the forearm central controller is BC of the forearm internal bus and RT of the robotic arm through-cabin bus).

[0122] Example 2: Robotic arm control panel controls the information flow of the upper arm: Robotic arm control panel BC → RT upper arm end effector RT → upper arm central controller BC → RT upper arm joint; (where the upper arm end effector is RT on the upper arm internal bus and also RT on the robotic arm through-cabin bus).

[0123] In the combined boom and forearm bus configuration, when the boom and forearm are connected in series, the free end of the boom (the end not connected to the cabin) switches to BC (Browser Connector) to communicate with the central controller of the forearm. Its data communication protocol remains consistent with the communication protocol when the forearm operates independently and is directly connected to the control panel inside the cabin (thus, the forearm can adapt to different BCs for communication). The boom, as a whole, provides transparent transmission for telemetry and remote control between the forearm and the control panel. The bus cables connecting the boom and forearm are laid out within the structure providing the mechanical connection between the boom and forearm (dual-boom combination adapter).

[0124] During the crawling process, the robotic arm has two ends simultaneously connected to the cabin. At this time, the free end of the robotic arm connected to the cabin is directly connected to the robotic arm system's through-cabin bus. Therefore, the robotic arm control panel, as the BC (Browser / Controller), should be designed with logic to maintain normal communication with the robotic arm during the crawling process of both the upper and lower arms. For example... Figure 7 Judgment strategy: BC uses the currently online endpoint as the fixed endpoint. If this endpoint is always online or there is no other online endpoint when it is offline, BC selects this endpoint as the fixed endpoint. If this endpoint is offline and another endpoint is online, BC selects that other endpoint as the fixed endpoint. Alternatively, the ground can specify which RT (Retrieval Unit) to use as the fixed endpoint (i.e., autonomous judgment is prohibited).

[0125] Figure 8 This is a schematic diagram of a bus selector switch. When the control terminal of the bus selector switch is not energized, the switch closes along the direction of the dotted line in the diagram, connecting the buses at both ends. When the control terminal of the bus selector switch is energized, the switch connects to a matching load, ensuring that the left bus operates normally.

[0126] During core module launch and single-module flight, such as Figure 4As shown, bus selectors 83, 84, 85, and 86 are all switched to the terminal load. The boom can crawl on "Boom Base," "Boom Adapter HA," "Boom Adapter HB," and "Boom Adapter HC." During crawling, the boom adapter provides a direct path for the bus branch, eliminating the need for bus selectors. This means the RT device can directly connect to the bus branch. However, this presents a situation where both ends of the robotic arm are connected to the cabin. The robotic arm control panel needs to employ a software strategy to ensure communication with only one end at a time. This decision-making strategy saves on the need for bus selectors for device connection and avoids information conflicts caused by the robotic arm's connections to the cabin at both ends.

[0127] The robotic arm's on-orbit tasks can be completed with the support of the upper arm, lower arm, or combined arm. Before completing the task, the state should be prepared, so the following standard process state switching scheme is designed.

[0128] Taking the "crawling" of the robotic arm from the base to the HC as an example, this paper explains the bus topology changes and information flow principles during the crawling of the large arm.

[0129] Step 1: Power on. The power-on sequence is: control panel → first terminal → central controller → second terminal.

[0130] Step 2: At this point, all the above devices are powered on. The second end effector is a free end effector and has not yet connected to the HC (core cabin adapter C). Although powered on, it is not connected to the cabin, meaning the second end effector is not connected to the bus system. Therefore, the robotic arm operator cannot detect that the second end effector is online. The operator determines that the first end effector is online, so it first selects the first end effector to communicate with the main arm (communication content: periodic, such as the operator collecting robotic arm telemetry data; sudden, such as the operator sending robotic arm control commands). The first end effector acts as the RT on the "robotic arm system through-cabin bus". After detecting that the operator is communicating with it, it sets the "communication status with operator controller" in the preset sub-address message to "communicating with operator". The first end effector also acts as the RT on the main arm internal bus, preparing status data on this bus and waiting for periodic collection by the main arm central controller BC. The second end effector is a free end effector, and sets the "communication status with operator controller" in the preset sub-address message to "not communicating with operator". The main arm central controller detects this flag and then... Figure 6 The logic establishes communication with the first end (i.e., sending full-arm telemetry to the first end, responding to instructions forwarded by the first end, etc.), thus ensuring that the information routing of BC devices in the two sets of buses all pass through the first end, and the information path of each device is fully open.

[0131] Step 3: At this point, the second end effector is a free end effector. The robotic arm moves and grasps the HC, controlled by ground control or the astronaut. The second end effector's bus branch connects to the HC, meaning the second end effector is connected to the "robotic arm system through-cabin bus." The control panel then... Figure 7Logically, the first terminal is always online, so it is still selected to communicate with the boom. The operator console does not communicate with the second terminal. The communication flag of the first terminal, "Communication status with operator console controller", remains unchanged as "Communicating with operator console". The communication status of the boom's internal bus does not change. The information routing of the BC devices in the two bus systems all passes through the first terminal, and the information paths of all devices are fully open.

[0132] Step 4: With both ends of the robotic arm gripping the cabin adapter, power off the entire arm in the following order: second end → central controller → first end.

[0133] Step 5: After the entire arm completes one "crawling" step, power it up through the new adapter HC, following the order of second end → central controller → first end;

[0134] Step 6: The operator console first detects that the second end is online and selects it to communicate with the boom. After detecting the communication between the operator console and itself, the second end makes a communication mark on the corresponding data address in the boom bus, that is, it sets the "Communication status with operator console controller" to "Communicating with operator console" in a specific data bit. The boom central controller detects this mark and then... Figure 6 The logic also establishes communication with the second end, thus ensuring that the information routing of the BC devices in the two sets of buses all pass through the second end, and the information path of each device is fully open; the first end actuator is a free end, and sets the "communication status with the operator console controller" in the preset sub-address message to "not communicating with the operator console".

[0135] Step 7: The ground control or astronaut controls the first end-effector release base and moves the robotic arm away from the base. The first end-effector bus branch is disconnected from the "robotic arm system through-cabin bus". The control panel then proceeds according to... Figure 7 Logically, the second terminal is always online, so communication between the second terminal and the boom is still selected. The communication flag of the second terminal remains unchanged, the communication status of the bus within the boom remains unchanged, and all information paths of the devices are open.

[0136] The next step of the robotic arm's crawling can be achieved by following the switching method from steps 1 to 7 above. During the crawling process, there is no need to configure the bus selector switch or send additional setting commands (the function of ground forced setting is also retained for on-orbit fault handling). Information routing can be automatically completed simply by powering on and off during normal use of the equipment, ensuring that all equipment information is transmitted.

[0137] During the above process, after the operating console is powered on, it continuously collects the RT online status of the first end and the second end, and always selects one end as the communication RT. After the first end and the second end are powered on, they continuously update the "communication status with the operating console controller" and wait for the central controller of the boom bus to collect the data. The central controller periodically collects the "communication status with the operating console controller" of the two ends and selects the end that is "communicating with the operating console" as the device for transmitting telemetry and response commands.

[0138] After the forearm ascends with experimental module I, the two modules dock via the forward docking interface, as follows: Figure 4 As shown, bus selector switches 83 and 84 disconnect the terminal load; bus selector switches 85 and 86 disconnect 89 and 90; bus selector switches 89 and 90 disconnect 95 and 96; and bus selector switches 95 and 96 disconnect 89 and 90. This connects the robotic arm system's through-cabin bus-1 and through-cabin bus-3 via the forward interface. The actions of bus selector switches 85 and 86 disconnect the docking camera and upper arm base, which are only used during core cabin single-cabin flight, thus reducing the bus length. At this time, the upper arm and forearm can crawl on their respective adapters. "Upper Arm Adapter WA", "Upper Arm Adapter WB", "Forearm Base", "Forearm Adapter Wa", "Forearm Adapter Wb", and "Forearm Adapter Wc" also only provide direct bus passage without using bus selector switches. The control panel uses the same software strategy for the forearm, ensuring communication with only one end of the forearm at a time.

[0139] After Experiment Module II ascends, the core module, Experiment Module I, and Experiment Module II form a T-shaped configuration. Bus selector switches 85 and 86 switch to 89 and 90, respectively. Bus selector switches 89 and 90 connect to the docking port of Module II. Bus selector switches 83 and 84 switch to 81 and 82, respectively. Bus selector switches 81 and 82 connect to the docking port of Module I. The robotic arm system's through-module bus-1 and through-module bus-4 are connected through the docking port of Module II. The robotic arm system's through-module bus-2 and through-module bus-3 are connected to the docking port of Module I. The principle of the large and small arm adapters in Experiment Module II is the same as that in Experiment Module I.

[0140] With the T-configuration, the robotic arm system has a wide reach, with the upper arm and lower arm located at the farthest ends of Experiment Module I and Experiment Module II, respectively. Considering the physical distance of the wiring, the total length of the robotic arm system's bus through the modules will exceed 100 meters. In order to meet the design specification that the main line length in the bus system should not exceed 100 meters, the robotic arm operating console bus interface is designed as a dual BC system, with each BC corresponding to a single side bus. The application software design only needs to implement the functions of a single BC controller (unified acquisition of telemetry data, distribution of commands, etc.).

[0141] If a subsequent visiting spacecraft docks with the space station's T-shaped configuration via the forward docking port, the aforementioned robotic arm system's through-cabin bus-1 or through-cabin bus-2 can be used to achieve bus docking with the visiting spacecraft through a combination of five bus selector switches. Since the space station only has two robotic arms—the large arm and the small arm—which can reside on at most two different modules, it is sufficient to select either the forward docking port, Module I parking port, or Module II parking port to connect to the robotic arm control panel.

[0142] Switching between the combined and separated states of the upper and lower arms:

[0143] The robotic arm's on-orbit tasks can be completed with the support of the upper arm, lower arm, or combined arm. Before completing the task, the state should be prepared, so the following standard process state switching scheme is designed.

[0144] 1. Steps for the combined upper and lower arm task:

[0145] Step 1: Power on the suspension device and confirm its status.

[0146] Step 2: Power on the forearm to confirm standby mode.

[0147] Step 3: The upper arm crawls to the target adapter HB (HB: represents any adapter).

[0148] Step 4: Pre-program the boom or adjust the end of the multi-joint to be above the gripper adapter.

[0149] Step 5: Disconnect the heating circuit of the suspension device.

[0150] Step 6: Rotate the boom to freely grip the adapter.

[0151] Step 7: Release the suspension device.

[0152] Step 8: Disconnect the power to the suspension system.

[0153] Step 9: Set the boom PID parameters to medium.

[0154] Step 10: Move the upper arm with the adapter to the gripping point at the end of the forearm.

[0155] Step 11: The boom is in standby braking state.

[0156] Step 12: Adjust the forearm movement to the gripping point.

[0157] Step 13: Switch the forearm to zero-force mode to grip the adapter.

[0158] Step 14: Switch to safe mode for forearm.

[0159] Step 15: Power and communication between the forearm and WA are disconnected.

[0160] Step 16: Power supply and communication connection for the boom and arm assembly.

[0161] Step 17: Power on the forearm to confirm standby mode.

[0162] Step 18: Release WA in zero-force mode for forearm.

[0163] Step 19: Adjust the visual servo mode at the end of the forearm to 700mm above WA.

[0164] Step 20: After adjusting the forearm to the transport configuration, standby (standard configuration when the forearm is transported by the forearm after the forearm and forearm are combined).

[0165] Step 21: Adjust the upper arm to the specified configuration to facilitate the verification of the combined arm movement.

[0166] 2. Steps for separating the forearm and arm:

[0167] Step 1: Power on the suspension device and confirm its status.

[0168] Step 2: Confirm that the forearm is in the transfer configuration and ready for operation.

[0169] Step 3: Move the upper arm to the lower arm and then to the end of the lower arm to grasp the WA position.

[0170] Step 4: The boom rotates and the machine is ready to brake.

[0171] Step 5: Move the forearm to the visual servo initial point.

[0172] Step 6: Adjust the forearm to the visual servo position and position it ready for capture.

[0173] Step 7: Grasp WA in zero-force forearm mode.

[0174] Step 8: Switch to safe mode for forearm.

[0175] Step 9: Power supply and communication disconnected for the boom and arm.

[0176] Step 10: Power supply and communication between the forearm and WA are established.

[0177] Step 11: Establish communication between the forearm and the experimental module.

[0178] Step 12: Forearm rotation to zero force release adapter.

[0179] Step 13: Forearm rotates to vision servo and removes the adapter 700mm.

[0180] Step 14: The boom moves to bring the adapter into the capture tolerance range of the suspension device.

[0181] Step 15: The forearm is withdrawn and adjusted to its normal configuration storage state.

[0182] Step 16: The boom rotates to the free suspension device to grab the adapter.

[0183] Step 17: After releasing the end of the boom, move it back above the adapter.

[0184] Step 18: Connect the heating circuit of the suspension device.

[0185] Step 19: Power off the suspension device.

[0186] Step 20: The upper arm crawls to the normal HC configuration and is adjusted to the storage state.

[0187] illustrate:

[0188] Bus Controller (BC):

[0189] The bus controller is the terminal that organizes information transmission in a bus system. In the intrabus of a robotic arm, the central controller of the upper arm and lower arm is the bus controller; in the through-cabin bus of the robotic arm system, the robotic arm control panel is the bus controller; in the combined upper and lower arm bus, the end effector of the upper arm is the bus controller.

[0190] In bus communication, the bus controller BC is the active end, actively sending messages to or collecting messages from the RT.

[0191] Remote Terminal (RT):

[0192] Remote terminals are all terminals in a bus system that do not act as bus controllers or bus monitors.

[0193] In bus communication, the bus controller RT is the passive end, that is, the slave end of the master-slave bus system.

[0194] In summary, the designed bus system and its information flow transmission method are adapted to the frequent "crawling" of multiple robotic arms on the space station module, as well as the need for two arms to work in series and collaboratively. It also supports the docking process of the hovering spacecraft (International Cooperation Module) and the subsequent operation of the robotic arms on the visiting spacecraft. A simpler topology was adopted to ensure the success of on-orbit missions. Based on the changing bus topology, a simple and reliable switching logic was used to design an adaptive information flow transmission method, ensuring that the information flow of the robotic arm system is not lost and remains controllable during topology changes.

[0195] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications to the technical solutions of the present invention by utilizing the methods and techniques disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall fall within the protection scope of the technical solutions of the present invention.

Claims

1. A variable structure data bus transmission system for a symmetrical spatial robotic arm, characterized in that... The symmetrical space robotic arm includes two sets of robotic arms, referred to as the upper arm and the lower arm. Each upper arm and lower arm includes two end effectors, which are respectively installed on the joints at the beginning and end of the robotic arm. The bus transmission system includes a robotic arm through-cabin bus, an upper arm internal bus, and a lower arm internal bus. The robotic arm through-cabin bus includes a first robotic arm system through-cabin bus, a second robotic arm system through-cabin bus, a third robotic arm system through-cabin bus, and a fourth robotic arm system through-cabin bus. The first robotic arm system's cabin-penetrating bus and the second robotic arm system's cabin-penetrating bus are located in the core module; The third robotic arm system's cabin-penetrating bus is located in the first experimental cabin, and the fourth robotic arm system's cabin-penetrating bus is located in the second experimental cabin. The first robotic arm system's through-cabin bus and / or the second robotic arm system's through-cabin bus connect to the boom adapter or boom base; The boom adapter or boom base is used to connect the boom end effector; The third robotic arm system's through-cabin bus and / or the fourth robotic arm system's through-cabin bus connect to the boom adapter, boom base, forearm adapter, or forearm base. Forearm adapters or forearm bases are used to connect forearm end effectors; When the first experimental module docks with the core module, the third robotic arm system's through-cabin bus can interconnect with the first robotic arm system's through-cabin bus or the second robotic arm system's through-cabin bus via a hardware interface. When the second experimental module docks with the core module, the fourth robotic arm system's through-cabin bus can be interconnected with the first robotic arm system's through-cabin bus or the second robotic arm system's through-cabin bus via a hardware interface. The core module is equipped with a robotic arm control panel. The robotic arm control panel has dual BC interfaces. One BC interface is connected to the first robotic arm system's through-cabin bus, and the other BC interface is connected to the second robotic arm system's through-cabin bus. The robotic arm control panel, as the BC, communicates with the robotic arm's end effector and the inner bus of the upper arm through the upper arm adapter or upper arm base. It also communicates with the inner bus of the lower arm through the lower arm's end effector and the lower arm's inner bus through the lower arm adapter or lower arm base.

2. The variable structure data bus transmission system for the symmetrical spatial robotic arm according to claim 1, characterized in that... It also includes the first experimental module bulkhead connector, the second experimental module bulkhead connector, the first experimental module docking assembly, the second experimental module docking assembly, the third experimental module docking assembly, the core module first bulkhead connector, the core module second bulkhead connector, the core module third bulkhead connector, the first bus selector switch, the second bus selector switch, the third bus selector switch, the fourth bus selector switch, and the fifth bus selector switch. Each bus selector switch is a two-to-one switch, including a switch control terminal, a first branch, a second branch, and a combined branch. The first branch is connected to the combined branch or the second branch is connected to the combined branch through the switch control terminal. The first experimental module docking assembly is connected to the third robotic arm system through the cabin bus via the first experimental module bulkhead connector. The first experimental module docking assembly is also used to connect to the first bulkhead connector of the core module. The second experimental module docking assembly is connected to the fourth robotic arm system via the second experimental module bulkhead connector; the second experimental module docking assembly is also used to connect to the core module second bulkhead connector. The third experimental module docking assembly is used to connect with the third bulkhead connector of the core module. Both the first and second experimental modules can dock with the core module via the docking components of the third experimental module. The composite branch of the first bus gating switch is connected to the third bulkhead connector of the core module, the first branch is connected to the second branch of the second bus gating switch, and the second branch is connected to the first branch of the third bus gating switch. The first branch of the second bus selector switch is connected to the first bulkhead connector of the core module, the combined branch is connected to the second branch of the fourth bus selector switch, the first branch of the fourth bus selector switch is connected to the load, and the combined branch is connected to the second robotic arm system through-cabin bus. The second branch of the third bus selector switch is connected to the second bulkhead connector of the core module, the composite branch is connected to the first branch of the fifth bus selector switch, the second branch of the fifth bus selector switch is connected to the load, and the composite branch is connected to the first robotic arm system's through-cabin bus.

3. The variable structure data bus transmission system for the symmetrical spatial robotic arm according to claim 1, characterized in that... The two end effectors of the boom and forearm can be connected to an adapter or base on the surface of the cabin at one end, or both can be connected to different adapters or bases on the surface of the cabin. The two end effectors of the boom and forearm can perform a "crawling" action of alternating connection to the cabin in the form of "single-end connection-double-end connection-single-end connection", so as to realize the position transfer of the robotic arm on the surface of the space station.

4. The variable structure data bus transmission system for the symmetrical spatial robotic arm according to claim 3, characterized in that... Both the upper arm and the lower arm include two end effectors, a central controller, a joint controller, a monitoring camera, and an Ethernet switch. The central controller and the end effectors, joint controllers, and Ethernet switches are connected in a BC and RT relationship. The end effectors of the upper arm and the lower arm are also equipped with end cameras for target identification and pose measurement, which are also connected to the internal bus of the robotic arm via RT. The upper arm and the lower arm are also equipped with monitoring cameras, which are also connected to the internal bus of the robotic arm via RT.

5. The variable structure data bus transmission system for the symmetrical spatial robotic arm according to claim 4, characterized in that... At any given time, only one of the two end effector controllers of the robotic arm communicates with the robotic arm's control panel. The end effector containing this controller is designated as the fixed end effector. The other end effector does not communicate with the robotic arm's control panel; the end effector containing this controller is designated as the free end effector. The fixed end effector is used to facilitate communication between the robotic arm's control panel inside the transfer compartment and the central controller within the robotic arm. Specifically: The robotic arm control panel determines whether the robotic arm's end controllers are online by polling the online status of the two end controllers of the robotic arm. The end controller that is online first is selected as the fixed end controller. If this end controller is always online or there is no other end controller online when it is offline, the end actuator corresponding to this end controller is selected as the fixed end controller. If this end controller is offline and the other end controller is online, the end actuator corresponding to the other end controller is selected as the fixed end controller. The terminal controller of the fixed terminal sets the "communication status with the console controller" in the preset sub-address message to "communicating with the console"; the terminal controller of the free terminal sets the "communication status with the console controller" in the preset sub-address message to "not communicating with the console". The central controller inside the robotic arm determines the fixed end effector by querying the "communication status with the console controller" in the preset sub-address information of the end effector corresponding to the end effector.

6. The variable structure data bus transmission system for the symmetrical spatial robotic arm according to claim 5, characterized in that... When the robotic arm operating console sends data to the main arm central controller, in the robotic arm system's through-cabin bus, the robotic arm operating console, acting as the BC, communicates with the fixed end, which acts as the RT. The fixed end moves the data sent by the robotic arm operating console to the address space agreed upon by the main arm internal bus system. In the main arm internal bus system, the main arm central controller, acting as the BC, reads the data from the fixed end, which acts as the RT. When the central controller of the boom sends data to the robotic arm operating table, in the boom intrabus system, the central controller of the boom, acting as the BC, communicates with the fixed end, which acts as the RT. The fixed end moves the data sent by the central controller to the address space agreed upon by the robotic arm system through-cabin bus. In the robotic arm system through-cabin bus, the robotic arm operating table, acting as the BC, communicates with the fixed end, which acts as the RT.

7. The variable structure data bus transmission system for the symmetrical spatial robotic arm according to claim 5, characterized in that... The information flow of the robotic arm operating console sending data to the upper arm joint is as follows: In the robotic arm through-cabin bus, the robotic arm operating console, as BC, communicates with the fixed end, which is the RT. The fixed end moves the content of the communication with the robotic arm operating console to the address space agreed upon by the upper arm internal bus. In the upper arm internal bus, the upper arm central controller, as BC, collects the data moved by the fixed end, and sends it to the upper arm joint, which is the RT, after address judgment. Conversely, in the inner bus of the boom, the central controller of the boom, acting as the BC, communicates with the boom joint, which acts as the RT, and forwards the content sent by the boom joint to the robotic arm operating console to the fixed end effector. The fixed end effector moves the content sent by the boom joint to the robotic arm operating console to a preset address space. In the robotic arm through-cabin bus, the robotic arm operating console, acting as the BC, queries the fixed end effector, which acts as the RT, to read the data.

8. The variable structure data bus transmission system for the symmetrical spatial robotic arm according to claim 5, characterized in that... After the forearm end effector is connected to the robotic arm's through-cabin bus via an adapter or forearm base, the branch lines of the robotic arm's through-cabin bus run through the forearm arm to the forearm central controller; the information flow of the robotic arm control panel for controlling the forearm is as follows: In the robotic arm through-cabin bus, the robotic arm control panel, acting as the BC, communicates with the forearm central controller, which acts as the RT; in the forearm intra-bus, the forearm central controller, acting as the BC, communicates with the forearm joint.

9. The variable structure data bus transmission system for the symmetrical spatial robotic arm according to claim 1, characterized in that... It also includes a dual-arm combination adapter suspension device, which serves as the RT access to the robotic arm through-cabin bus. This dual-arm combination adapter suspension device is used to carry the "adapter". The "adapter" can be grabbed or released by the upper arm or the lower arm to connect the upper arm and the lower arm in series, ensuring mechanical, power supply and information connectivity between the upper arm and the lower arm. When the boom and forearm work independently on the cabin, the "adapter" is placed on this "suspension device"; when the boom and forearm need to form a series combination, the "suspension device" releases the "adapter" and hands it over to the free end of the boom for gripping, and the free end of the forearm then grips the forearm adapter interface of the adapter carried on the end of the boom, thus realizing the series connection of the two booms.

10. The variable structure data bus transmission system for the symmetrical spatial robotic arm according to claim 8, characterized in that: When the boom and forearm are connected in series, the free end of the boom switches to the BC in the boom-forearm combined bus system to communicate with the central controller of the forearm. Its data communication protocol is consistent with the communication protocol when the forearm works alone and is directly connected to the control panel inside the cabin. The boom, as a whole, transparently transmits telemetry and remote control data between the forearm and the robotic arm control panel. The bus cables connecting the boom and forearm are laid in the adapter that provides mechanical connection between the boom and forearm.

11. A variable structure data bus transmission method for a symmetrical spatial robotic arm based on the system of claim 10, characterized in that: The information control method for the "crawling" motion process, which involves alternating "single-end connection - double-end connection - single-end connection" between the two end effectors of the boom or forearm connecting the cabin, is as follows: S1. Power on the robotic arm control panel, the first end effector, the central controller, and the second end effector in that order. S2. The robotic arm control panel detects the online end effector and determines that the first end effector is a fixed end effector, communicating with the main arm through the online first end effector. At the same time, the end effector of the first end effector acts as the RT on the robotic arm system's through-cabin bus. After detecting that the robotic arm control panel BC is communicating with it, it makes a communication mark on a specific data address in the main arm bus, that is, sets the "communication status with control panel controller" in the preset sub-address message to "communicating with control panel". The first end effector also acts as the RT on the main arm's internal bus, preparing status data on this bus, waiting for the periodic acquisition by the main arm central controller BC. The second end effector is a free end effector, and sets the "communication status with control panel controller" in the preset sub-address message to "not communicating with control panel". S4. The central controller of the boom determines that the "communication status with the operator console controller" of the first end is "communicating with the operator console". It establishes communication with the first end, thus ensuring that the information routing of the BC devices in the two sets of buses all pass through the first end, and the information path of each device is fully open. S5. The robotic arm moves and grabs the robotic arm adapter or base under the control of the ground or astronaut. The second end effector bus branch is connected to the adapter. The robotic arm control panel determines that the first end is always online and still chooses to communicate with the main arm through the first end, without communicating with the second end. The communication flag of the first end, "Communication status with control panel controller", remains unchanged as "Communicating with control panel". The communication status of the internal bus of the robotic arm does not change. The information routing of the BC devices in the two sets of buses is still through the first end, and the information paths of each device are fully open. S6. With both ends of the robotic arm gripping the cabin adapter, power off the entire arm in the following order: second end, central controller, and first end. S7. With the dual-end connected cabin in the state, power on via the new adapter, in the order of the second end, central controller, and first end; S8. The robotic arm control panel first determines that the second end effector is online and selects the second end effector to communicate with the main arm. After the second end effector detects that the control panel is communicating with itself, it makes a communication mark on the corresponding data address in the main arm bus, that is, it sets the "communication status with control panel controller" in a specific data bit to "communicating with control panel". After the main arm central controller determines this mark, it also establishes communication with the second end effector, ensuring that the information routing of the BC devices in the two sets of buses all pass through the second end effector and the information path of each device is fully open; the first end effector is a free end effector, and sets the "communication status with control panel controller" in the preset sub-address message to "not communicating with control panel". S9. The ground or astronaut controls the first end to release the base and control the robotic arm to move away from the base. The first end bus branch is disconnected from the "robotic arm system through-cabin bus". The control panel determines that the second end is always online and still selects the second end to communicate with the main arm. The communication mark of the second end does not change. The communication status of the main arm's internal bus does not change. All information channels of each device are open. S10. Repeat steps S5 to S9 above to maintain communication while the robotic arm continues to "crawl" to other adapters.

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