Multi-mechanical-arm consistency control method based on event triggering under communication limitation

Abstract

The invention discloses a multi-mechanical-arm consistency control method based on event triggering under communication limitation. The method comprises the steps that a multi-mechanical-arm system model is established for a multi-mechanical-arm system based on the algebraic graph theory; for the multi-mechanical-arm system model, performing algorithm control on each mechanical arm through a distributed consistency control algorithm; when consistency control is carried out on the mechanical arms, a communication protocol is triggered through a preset event, and communication between the mechanical arms is controlled; and when the multiple mechanical arms need to send the state information, communication channels are allocated to the multiple mechanical arms through a preset channel scheduling strategy. According to the technical scheme provided by the embodiment of the invention, the utilization rate of the communication channel of the mechanical arm is improved and the limited channel use condition is improved by designing the channel scheduling strategy based on event triggering under the condition that the channel is limited.

Description

Technical Field

[0001] The present invention relates to the technical field of multi-robot control, and in particular to a multi-robot consistency control method based on event triggering under limited communication. Background Art

[0002] With the rapid development of science and technology, the proportion of the robot industry in today's industrial field is getting larger and larger. It can be seen that more and more industrial production lines have appeared robotic arms. As the most important component of the robot, the robotic arm itself has the characteristics of multi-input and multi-output, nonlinearity, and strong coupling.

[0003] However, on the production line, multiple robotic arms work together, which increases the difficulty of controlling multiple robotic arms. Moreover, due to the limited communication resources between the robotic arms, the information of each robotic arm cannot be transmitted to other robotic arms in time, and the general robotic arm control algorithm cannot control the multi-robotic arm system well.

[0004] Therefore, how to effectively utilize communication resources, reduce the communication frequency between robotic arms, and improve the utilization of robotic arm communication channels is an urgent problem to be solved. Summary of the invention

[0005] In view of this, the purpose of the present invention is to provide a multi-robot arm consistency control method based on event triggering under communication constraints, and to improve the utilization rate of the robot arm communication channel and the use of limited channels by designing a channel scheduling strategy based on event triggering under channel constraints.

[0006] To achieve the above-mentioned object of the invention, the present invention provides a multi-manipulator consistency control method based on event triggering under communication constraints, the method comprising:

[0007] Establish a multi-manipulator system model based on algebraic graph theory;

[0008] For the multi-manipulator system model, each manipulator is controlled by a distributed consistency control algorithm;

[0009] When the consistency control of each robot arm is performed, the communication protocol is triggered by the preset event to control the communication between the robot arms;

[0010] When multiple robotic arms need to send status information, communication channels are allocated to the multiple robotic arms through a preset channel scheduling strategy.

[0011] Furthermore, the establishing of the multi-manipulator system model includes:

[0012] Constructing a communication topology of a weighted undirected graph of the multi-manipulator system;

[0013] In the communication topology, establishing a communication link between any robot arm and its neighboring robot arm;

[0014] Each robotic arm is used as a node of the communication topology to construct a dynamic model of any robotic arm.

[0015] Furthermore, the dynamic model of the i-th robot arm is:

[0016]

[0017] Where i represents any robot arm, Z refers to the number of nodes in the communication topology, and M i (θ i ) is the system generalized inertia matrix, is the Coriolis matrix of the system including the centrifugal force, G i (θ i ) is the generalized gravity vector, u i (t) is the control input of the i-th robot at time t, θ i is the generalized coordinate of the ith robot, is the generalized velocity of the ith robot arm.

[0018] Furthermore, the construction process of the distributed consistency control algorithm includes: designing multi-robot arm distributed consistency control input based on multi-agent consistency theory.

[0019] Furthermore, it is characterized in that the function formula of the control input is:

[0020]

[0021] Where i refers to the i-th robot, j refers to the j-th neighbor robot of the i-th robot, N refers to the number of neighbor robots of the i-th robot, and u i (t) is the control input of the i-th robot at time t, θ i is the generalized coordinate of the i-th robot, θ j is the generalized coordinate of the jth neighbor robot of the ith robot, is the generalized velocity of the ith robot, a ij are the elements in the adjacency matrix of the communication topology, is the event triggering time of the i-th robot arm, is the next event triggering time of the i-th robot arm, is the jth neighbor robot of the ith robot in the interval The event triggering time in T i is the gain matrix of the i-th robot, G i (θ i ) is the generalized gravity vector of the ith robot arm.

[0022] Further, an event triggering function and an event triggering condition are set in the event triggering communication protocol;

[0023] The event detector of any robot arm samples the local sensor information, performs calculation according to the event trigger function, and determines whether the robot arm meets the event trigger condition;

[0024] When the event triggering condition is met, the trigger switch is closed, the control input of any one of the robotic arms is updated, and the state information at the triggering moment is sent to the neighboring robotic arm.

[0025] Furthermore, for any of the robotic arms, at other times except the event triggering moment, any of the robotic arms is controlled not to transmit information with its neighboring robotic arms.

[0026] Furthermore, the channel scheduling strategy divides the sending of status information by the robot arm into two stages;

[0027] In the first stage, the calculated value of the event trigger function is used to provide a corresponding probability information transmission strategy according to the size of the calculated value to transmit state information; the information transmission strategy determines whether to initiate a communication request based on the probability result, and uses the communication channel when initiating a communication request;

[0028] In the second stage, for the robotic arms that meet the event triggering conditions but do not initiate a communication request in the first stage, the CSMA / CA communication strategy is used to transmit status information.

[0029] Furthermore, the workflow of any robot arm is:

[0030] The event detector performs real-time detection on any of the robotic arms, and any of the robotic arms obtains its own state information and the state information of its neighboring robotic arms, and then determines whether any of the robotic arms meets the event triggering condition. If the event triggering condition is not met, the event detector continues to obtain the state information of any of the robotic arms itself and the state information of its neighboring robotic arms in real time;

[0031] If the event triggering condition is met, any one of the robotic arms updates its own control input using its own state information and the state information of its neighboring robotic arms, and finally updates the state information.

[0032] Furthermore, if the event triggering condition is met, it also includes: any one of the mechanical arms enters the first stage of the information transmission strategy, determines whether to initiate a communication request with probability and use the communication channel in the first stage; if any one of the mechanical arms does not initiate a communication request in the first stage, enters the second stage using the CSMA / CA communication mechanism, accesses the communication channel to send the state information of any one of the mechanical arms;

[0033] If a communication request is initiated with probability in the first stage, the communication channel is accessed to send any of the robot arm status information.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] The technical solution of the present invention, under the condition that the communication channel of the robot arm is limited, can, based on the event-triggered channel scheduling strategy, effectively prompt the robot arm with a large calculated value of the event trigger function to more actively send status information to the neighboring robot arm when the number of robot arms that meet the event trigger conditions is greater than the limited number of communication channels of the wireless communication network, thereby helping to improve the utilization rate of the robot arm communication channel and improve the use of limited channels.

[0036] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present invention, nor are they intended to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only preferred embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0038] Figure 1 It is a method flow chart of a method for event-triggered multi-manipulator consistency control under limited communication provided by an embodiment of the present invention;

[0039] Figure 2 It is a structural principle diagram of an event-triggered communication protocol provided by an embodiment of the present invention;

[0040] Figure 3 This is a workflow diagram of a single robotic arm provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0041] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0042] It should be noted that the terms "including" and "having" and any variations thereof in the specification and claims of the present invention and the above-mentioned drawings are intended to cover non-exclusive inclusions. For example, a process, method, system, product or apparatus comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or apparatus.

[0043] Embodiment 1

[0044] Before the specific embodiments of the present invention are introduced, the existing patent CN118848995A has provided an event-triggered fault-tolerant control method for a robotic arm system, which detects faults by real-time monitoring of robotic arm data, matches faults using a preset fault adjustment rule library and executes corresponding control strategies, compares real-time robotic arm data with preset motion trajectories, analyzes errors and dynamically adjusts control strategies in combination with fuzzy control algorithms, generates optimized motion trajectory commands, and then performs safety detection on the robotic arm that executes the optimized trajectory commands. However, there is a problem of limited communication resources between robotic arms, and there is still no event-triggered channel scheduling strategy for channel-limited situations.

[0045] The embodiment of the present invention proposes a multi-manipulator consistency control method based on event triggering under communication limitation. Figure 1 The method flow chart of a method for controlling consistency of multiple robotic arms based on event triggering under limited communication provided in the first embodiment of the present invention is applicable to the situation where communication resources between robotic arms are limited. The method can be executed by a multi-robotic arm control system based on event triggering, and the multi-robotic arm control system based on event triggering can be configured in a multi-robotic arm system. Figure 1 As shown, the method specifically comprises the following steps:

[0046] S101. Establish a multi-manipulator system model based on algebraic graph theory.

[0047] In order to design a good control algorithm for the multi-manipulator system, a model is built for the multi-manipulator system based on algebraic graph theory. The embodiment of the present invention considers a system consisting of N rigid manipulators with n degrees of freedom, describes the multi-manipulator system as a multi-agent system using graph theory, and gives the dynamic equations and physical parameter descriptions satisfied by the multi-manipulator system in combination with actual physical laws.

[0048] It should be noted that algebraic graph theory is an important branch of graph theory, which mainly studies the relationship between graphs and matrices and their properties. It uses algebraic tools and methods to solve problems in graph theory, especially in the representation of graphs, basic relations, subgraphs and spanning trees.

[0049] Among them, the multi-manipulator system model is established, including:

[0050] S1011. Construct the communication topology of the weighted undirected graph of the multi-robotic arm system.

[0051] In the embodiment of the present invention, in order to design a good control algorithm for the multi-manipulator system, a model is built for the multi-manipulator system based on the algebraic graph theory. In a system consisting of N manipulators, the communication topology of the weighted undirected graph of the multi-manipulator system is defined as G = (Z, E), where Z is the set of topological graph nodes, Z = {1, 2, ..., N}, and E is the set of topological graph edges. N is the number of robotic arms.

[0052] S1012: In the communication topology, establish a communication link between any robotic arm and its neighboring robotic arms.

[0053] It should be noted that in a multi-robotic arm system, all robotic arms can be regarded as independent intelligent agents. The intelligent agent is an entity that resides in the environment. It can interpret the data obtained from the environment that reflects the events occurring in the environment and perform actions that affect the environment. It can be either hardware (such as a robot) or software.

[0054] For the sake of ease of description, the “ith robotic arm” will be abbreviated as “robotic arm i” and the “jth neighbor robotic arm of the ith robotic arm” will be abbreviated as “robotic arm j”.

[0055] The set of agents adjacent to robot arm i can be represented as N i , N i There exists a neighbor robot j of robot i, satisfying j∈Z and (j,i)∈E, |N i |YesN i The cardinality of .

[0056] It should be noted that for any robot arm i, it is also regarded as its neighboring robot arm, that is, its neighboring robot arms include all robot arms. Among them, it is meaningless for robot arm i to communicate with robot arm i, that is, a ii = 0; there are two situations when robot arm i communicates with a neighbor robot arm j other than itself. The first one is that robot arm i does not communicate with robot arm j, that is, a ij = 0; the second is: robot arm i communicates with robot arm j, using a ij Indicates that i and j both belong to N.

[0057] Construct the adjacency matrix A of the system communication topology graph, A = [a ij ]∈R N×N And satisfy the non-negative element a ij =a ji .a ijis the element in the i-th row and j-th column of the adjacency matrix A, representing the communication link between robot i and robot j. The degree of robot i in the communication topology is defined as

[0058] Specifically, an edge in the topology graph G is defined as (i, j), which represents the communication link between agent i and agent j. No agent in the communication topology graph is allowed to communicate with itself, so we can get a ii = 0. When robot arm i communicates with robot arm j, a ij >0.

[0059] Furthermore, we can get the Laplace matrix of the topological graph L = [l ij ]∈R N×N ,definition Among them, l ij With l ii are the elements of the Laplacian matrix.

[0060] S1013: Take each robotic arm as a node of the communication topology and construct a dynamic model of any robotic arm.

[0061] For the dynamics of the N-manipulator system, each manipulator is regarded as a node in the communication topology graph, whose set is Z = {1, 2, ..., N}. The dynamic model of manipulator i is:

[0062]

[0063] Among them, M i (θ i )∈R N×N is the system generalized inertia matrix, is the Coriolis matrix of the system including the centrifugal force, G i (θ i )∈R N×N is the generalized gravity vector, u i (t)∈R N is the control input of robot i, θ i ∈R N is the generalized coordinate of robot i, is the generalized velocity of robot i.

[0064] In the dynamic model of the robot arm, the state error of the robot arm can be obtained according to the generalized coordinate measurement error and the generalized velocity measurement error of the robot arm.

[0065] The generalized coordinate measurement error of robot arm i is:

[0066]

[0067] The measurement error of the generalized velocity of robot arm i is:

[0068]

[0069] According to the measurement errors of generalized coordinates and generalized velocities, the state error of robot i can be obtained as:

[0070]

[0071] in, is the event triggering moment of robot i, which satisfies the condition k∈N. This moment is obtained by robot i calculating its own event triggering condition.

[0072] It should be noted that the state of each robot arm is updated through the dynamic model.

[0073] S102, for the multi-manipulator system model, each manipulator is controlled by a distributed consistency control algorithm.

[0074] In order to achieve good consistency control of the multi-robot system, the embodiment of the present invention designs a distributed consistency controller algorithm for the multi-robot system. The state error between the actual state and the triggering moment of each robot is measured, and a distributed consistency control protocol for a single robot is designed in combination with the consistency theory of the multi-agent system, so that the multi-agent system composed of multiple robots can achieve effective consistency control.

[0075] Specifically, the distributed controller algorithm of the multi-robot system includes: designing the distributed consistency control input of the multi-robot system based on the multi-agent consistency theory.

[0076] Among them, the function formula of control input is:

[0077]

[0078] in, is the event triggering time of robot arm i, is the next event triggering time of robot arm i, is the neighbor robot j in the interval The event triggering time in T i is the gain matrix of robot i, G i (θ i ) is the generalized gravity vector of robot i.

[0079] It can be seen from the consistent control input expression of robot arm i that the consistent control input of robot arm i is not only related to the state of robot arm i, but also to the state of robot arm j adjacent to robot arm i. That is, the consistent control input of robot arm i is To implement the update, also at the time of the event triggering of the neighbor robot arm j To achieve the update. That is, the distributed consistency control input of multiple robotic arms can be rewritten as:

[0080]

[0081] S103, when the consistency algorithm is controlled for each robotic arm, the communication between the robotic arms is controlled by triggering the communication protocol through a preset event.

[0082] In order to effectively reduce the communication burden in the robotic arm system and reduce the communication frequency between each robotic arm, an event-triggered communication protocol is designed according to the event trigger mechanism in the embodiment of the present invention. The event trigger function in the communication protocol is composed of the state error function of each robotic arm and the designed threshold function. The setting of the event-triggered communication protocol can effectively reduce the communication frequency between the robotic arms and reduce the communication burden.

[0083] In order to effectively reduce the communication burden in the multi-robotic arm system and reduce the communication frequency between the various robotic arms, an embodiment of the present invention designs an event-triggered communication protocol based on an event-triggered mechanism.

[0084] Figure 2 is a schematic diagram of the structure of an event-triggered communication protocol provided by an embodiment of the present invention, such as Figure 2 As shown, the event-triggered communication scheme uses event-triggered detection to determine whether robot arm i updates its own control input and sends status information to neighboring robot arms.

[0085] The principle is: the event trigger function and event trigger conditions are pre-set in the event trigger communication protocol, the event detector of robot arm i samples the local sensor information, and calculates according to the pre-defined event trigger function to determine whether robot arm i meets the event trigger condition. When the event trigger condition is met, the trigger switch will be closed, and robot arm i uses the received state information of the neighbor robot arm and its own state information to update the control input, and sends the state information at the trigger time to the neighbor robot arm.

[0086] The setting of the event-triggered communication protocol is to achieve system consistency control under the premise of reducing the number of communications between each robot. From the consistency control input expression of robot i, it can be obtained that each robot is updated at its own event triggering time and the neighboring robot event triggering time. According to the event triggering theory, the next triggering time of robot i is defined as:

[0087]

[0088] For robot arm i, the event trigger function is designed as follows:

[0089]

[0090] in, β i are the preset coefficients, α, λ i , γ i , τ i are constants, T i is the gain matrix of robot i, T max With T min Yes T i The largest and smallest elements in , σ i (t) is the function to be determined, T min =min{T i}, T max =max{T i},0<λ i <1, is the exponentially decaying gain, is an exponential decay rate and satisfies

[0091] It can be seen from the event trigger function that when the event trigger function meets the trigger condition The defined event is triggered when the event is triggered. The event triggering time of each robot arm is calculated by the state variable of the robot arm. Is the calculated value greater than or equal to 0? When it is greater than or equal to 0, the control input of the robot arm is updated and remains unchanged until the next event is triggered. For any robot, at other times except the event triggering moment, it is controlled not to transmit information with its neighboring robot. That is, the control input remains unchanged between two adjacent event triggering moments, and robot i does not transmit information with its neighboring robot during the event triggering interval. Therefore, this event triggering strategy reduces the communication burden in the multi-robot system and reduces the communication frequency between each robot.

[0092] For a multi-robotic arm system, under the condition that the system communication topology is connected, any robotic arm of the multi-robotic arm system can reach consensus under the distributed consistency control algorithm and event triggering strategy.

[0093] S104: When multiple robotic arms need to send status information, communication channels are allocated to the multiple robotic arms through a preset channel scheduling strategy.

[0094] Due to the limited communication resources, the mechanical arms that meet the event triggering conditions at the same time cannot use the limited communication channels to transmit data at the same time. To solve this problem, the embodiment of the present invention designs a channel scheduling strategy.

[0095] The channel scheduling strategy divides the period when the robot sends status information into two stages. In the first stage, the calculated value of the event trigger function is used to propose an information transmission strategy with corresponding probability according to the size of the calculated value. The communication request is determined by probability and the communication channel is used when the communication request is initiated. In the second stage, for the robot that meets the event trigger conditions but does not initiate a communication request in the first stage, the CSMA / CA communication strategy is used to realize the transmission of the robot status information.

[0096] Specifically, based on the event-triggered communication strategy, define the binary variable ξ i ∈{1,0} indicates whether robot arm i meets the event triggering condition

[0097] Definition i = 0 means that robot arm i does not meet the event triggering condition and does not need to send its own status information to neighbor robot arm j. Define ξ i =1 means that robot arm i meets the event triggering condition, and robot arm i can access the communication channel to send its own status information to neighbor robot arm j. Binary variable ξ i The expression is:

[0098]

[0099] All the robotic arms in the multi-robotic arm system share the same wireless communication network with limited communication resources. The limited communication resources here refer to the channel limitation caused by the limited bandwidth of the wireless spectrum, that is, at any time t, the wireless communication network allows at most ε robotic arms to successfully access the limited communication channel. It can be expressed as the following expression:

[0100]

[0101] From the event-triggered communication strategy, we can see that at the same time, multiple robotic arms may meet the event triggering conditions and send status information to neighboring robotic arms. However, when robotic arm i initiates a request to access the communication channel, it may not be able to successfully compete for the right to use the communication channel.

[0102] Defining binary variables It means that robot arm i initiates a request to access the communication channel at the time of its event triggering and successfully accesses the communication channel.

[0103] make If robot arm i fails to access the channel successfully, it cannot send its own status information to its neighbor robot arm j. For robot i to successfully access the channel, it can send its own status information to its neighbor robot j. Binary variable The expression is:

[0104]

[0105] If at the same time, the number of robotic arms that meet the event triggering conditions is less than or equal to the limited number of communication channels in the wireless communication network ε, then the robotic arms that meet the event triggering conditions can successfully access the communication channel and send status information to the neighboring robotic arms. However, when the number of robotic arms that meet the event triggering conditions is greater than the limited number of communication channels ε of the wireless communication network, The robotic arms that meet the event triggering conditions need to compete for limited communication channels. It follows the following Bernoulli distribution:

[0106]

[0107] From the above formula, we can get that the robotic arms that meet the event trigger conditions have the same probability of successfully competing to use the communication channel. In this case, only some of the robotic arms that meet the event trigger conditions can send status information. At this moment, for the multi-robotic arm system, some of the robotic arms cannot update the control input because they cannot obtain the status information of their neighbors, so it is impossible to achieve good control of the multi-robotic arm system.

[0108] The embodiment of the present invention designs a channel scheduling strategy. The strategy is divided into two stages. In the first stage, a corresponding probability information transmission strategy is designed based on the calculated value of the event trigger function. The strategy has the following structure:

[0109]

[0110] in, It is a parameter defined based on the calculated value of the event trigger function of the robot arm i, which is specifically expressed as: The larger the calculated value of is, the higher the calculated probability ω i The bigger.

[0111] Based on the above probability information transmission strategy, we can get that in the first stage, the event triggering conditions are met and The robot arm with a larger calculation value is more likely to successfully initiate a communication request and use the communication channel.

[0112] For the robot arm that meets the event triggering conditions but does not initiate a communication request in the first stage, it will enter the second stage.

[0113] In the second phase of the designed channel scheduling strategy, the robot arm will adopt the CSMA / CA communication mechanism to realize the transmission of robot arm status information.

[0114] CSMA / CA is Carrier Sense Multiple Access. This access method is used for carrier transmission in wireless networks. Just like wired networks, wireless networks also need to avoid collisions of communication information. However, since wireless networks have no cables, the systems connected to the network cannot sense or monitor whether there is a collision of information in the network when sending data. Therefore, in this mode, when a system wants to send data, it will first sense whether there is other information transmission in progress. If other transmissions are detected, the system will wait for a short time and then check the network. If no other transmissions are detected, the system will randomly wait for a short time and send data. When the destination receives the data, it will respond to the sending system with a received message to inform that the data has been received. However, if the sending system does not receive the received message from the destination, the sending system will start the above process again.

[0115] For the robotic arms in the second stage, each robotic arm will use the CSMA / CA communication mechanism to send its own status information to its neighboring robotic arms. The robotic arms entering the second stage must compete for the remaining idle channels with equal probability to ensure that all robotic arms that meet the event trigger conditions at this moment send status information, thereby achieving good control of the multi-robotic arm system.

[0116] Figure 3 This is a workflow diagram of a single robotic arm provided by an embodiment of the present invention, such as Figure 3 As shown, under the method provided in the embodiment of the present invention, the workflow of a single robot arm i is:

[0117] Event detector i performs real-time detection on robot arm i, obtains the state information of robot arm i itself, and then determines whether robot arm i meets the event triggering condition. If the condition is not met, it continues to obtain the state information of robot arm i itself in real time;

[0118] If the trigger condition is met, on the one hand, robot i obtains the status information of the neighbor robot, then updates its own control input, and finally updates the status information;

[0119] On the other hand, the robot i that meets the event triggering condition enters the first stage of information transmission strategy. According to the calculated value of the event triggering function, it is determined whether to initiate a communication request and use the communication channel with probability in the first stage. If the robot i meets the event triggering condition but does not initiate a communication request in the first stage, that is, the channel cannot be obtained in the first stage, it enters the second stage using the CSMA / CA communication mechanism and accesses the communication channel to send the robot i status information.

[0120] If a communication request is initiated with probability in the first stage, the communication channel is accessed to send the state information of the robot arm i.

[0121] The technical solution of the embodiment of the present invention realizes effective control of the multi-robot system based on the multi-agent theory, and regards each robot as each agent in the multi-agent system, which is convenient for describing the complex multi-robot system. At the same time, the event-triggered communication mechanism and the channel scheduling strategy based on the event triggering result are adopted to effectively reduce the communication frequency between the robots, reduce the occupation of communication resources, and improve the utilization rate of the communication channel.

[0122] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A multi-manipulator consistency control method based on event triggering under limited communication, characterized in that: include: Establish a multi-manipulator system model based on algebraic graph theory; For the multi-manipulator system model, each manipulator is controlled by a distributed consistency control algorithm; When the consistency control of each robot arm is performed, the communication protocol is triggered by the preset event to control the communication between the robot arms; When multiple robotic arms need to send status information, communication channels are allocated to the multiple robotic arms through a preset channel scheduling strategy.

2. The method according to claim 1, characterized in that The multi-manipulator system model is established, including: Constructing a communication topology of a weighted undirected graph of the multi-manipulator system; In the communication topology, establishing a communication link between any robot arm and its neighboring robot arm; Each robotic arm is used as a node of the communication topology to construct a dynamic model of any robotic arm.

3. The method according to claim 2, characterized in that The dynamic model of the i-th robotic arm is: Where i represents any robot arm, Z refers to the number of nodes in the communication topology, and M i (θ i ) is the system generalized inertia matrix, is the Coriolis matrix of the system including the centrifugal force, G i (θ i ) is the generalized gravity vector, ui(t) is the control input of the i-th manipulator at time t, θ i is the generalized coordinate of the ith robot, is the generalized velocity of the ith robot arm.

4. The method according to claim 1, characterized in that: The construction process of the distributed consistency control algorithm includes: designing a multi-manipulator distributed consistency control input based on the state error of the manipulator and the multi-agent consistency theory.

5. The method according to claim 4, characterized in that The function formula of the consistency control input is: Where i refers to the i-th robot, j refers to the j-th neighbor robot of the i-th robot, N refers to the number of neighbor robots of the i-th robot, ui(t) is the control input of the i-th robot at time t, θ i is the generalized coordinate of the i-th robot, θ j is the generalized coordinate of the jth neighbor robot of the ith robot, is the generalized velocity of the ith robot, a ij are the elements in the adjacency matrix of the communication topology, is the event triggering time of the i-th robot arm, is the next event triggering time of the i-th robot arm, is the jth neighbor robot of the ith robot in the interval The event triggering time in T i is the gain matrix of the i-th robot, G i (θ i ) is the generalized gravity vector of the ith manipulator.

6. The method according to claim 4 or 5, characterized in that: Setting an event trigger function and an event trigger condition in the event trigger communication protocol; The event detector of any robot arm samples the local sensor information, performs calculation according to the event trigger function, and determines whether the robot arm meets the event trigger condition; When the event triggering condition is met, the trigger switch is closed, the control input of any one of the robotic arms is updated, and the state information at the triggering moment is sent to the neighboring robotic arm.

7. The method according to claim 6, characterized in that For any of the robotic arms, at other times except the event triggering moment, control any of the robotic arms not to transmit information with its neighboring robotic arms.

8. The method according to claim 6, characterized in that The channel scheduling strategy divides the sending of status information by the robot arm into two stages; In the first stage, the calculated value of the event trigger function is used to provide a corresponding probability information transmission strategy according to the size of the calculated value to transmit state information; the information transmission strategy determines whether to initiate a communication request based on the probability result, and uses the communication channel when initiating a communication request; In the second stage, for the robotic arms that meet the event triggering conditions but do not initiate a communication request in the first stage, the CSMA / CA communication strategy is used to transmit status information.

9. The method according to claim 8, characterized in that: The workflow of any robot arm is: The event detector performs real-time detection on any of the robotic arms, and any of the robotic arms obtains its own state information and the state information of its neighboring robotic arms, and then determines whether any of the robotic arms meets the event triggering condition. If the event triggering condition is not met, the event detector continues to obtain the state information of any of the robotic arms itself and the state information of its neighboring robotic arms in real time; If the event triggering condition is met, any one of the robotic arms updates its own control input using its own state information and the state information of its neighboring robotic arms, and finally updates the state information.

10. The method according to claim 9, characterized in that If the event triggering condition is met, it also includes: any one of the mechanical arms enters the first stage of the information transmission strategy, and determines whether to initiate a communication request to access the wireless communication network and use the communication channel with probability in the first stage according to the calculated value of the event triggering function; if any one of the mechanical arms does not initiate a communication request in the first stage, then enters the second stage using the CSMA / CA communication mechanism, accesses the communication channel and sends the state information of any one of the mechanical arms; If communication is initiated probabilistically in the first stage, the communication channel is accessed to send any of the robot arm status information.

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