CN105045094A - Task-search and task execution method for multiple robot groups - Google Patents

Abstract

The invention discloses a task-search and task execution method for multiple robot groups, comprising a task search layer strategy, and a task search flow. A task reception layer classifies the multi-robot cooperation into the following three forms according to different forms of the tasks and the different cooperation forms of the robots: multi-robot serial cooperation, multi-robot synchronization cooperation and multi-robot free cooperation. The invention is applicable to performing more complicated tasks, divides the complicated task into multiple parts and lets multiple robots to finish the task through mutual cooperation. Compared with the single robot, the task-search and task execution method for multiple robot groups is high in efficiency.

Description

The task search of multirobot colony and task executing method

Technical field

The present invention relates to a kind of task search and task executing method of multirobot colony.

Background technology

In recent years, along with the development need of science and technology, Robotics is progress constantly.Face the day by day complicated of task, single robot cannot meet production requirement in many circumstances, so researcher a large amount of concern to multirobot Technical investment both at home and abroad, proposes and utilizes multi-robot Cooperation to work to replace unit device people.

The research of multi-robot Cooperation is not the function of Ge Dan robot mutually being superposed on ordinary meaning, but by each child robot cooperative cooperating in system, plays the effect that one-plus-one is greater than two.Easily each robot function is superposed mutually, not only the advantage of multi-robot system cannot be highlighted, on the contrary when multi-robot system runs into complex situations, can cause clashing between each robot, and even stagnate or deadlock, reduce the execution efficiency of task.

Summary of the invention

The object of the present invention is to provide a kind of task search and task executing method of multirobot colony of serviceability excellence.

Technical solution of the present invention is:

The task search of multirobot colony and a task executing method, is characterized in that: comprising:

(1) task search layer strategy

Suppose that the position residing for the robot in task search layer is initial position, the node of initial position is S, robot is from initial position, random motion search task, the search radius r=10 of robot in alliance, if the task in environment and robot distance d are when [0,10], represent that robot searches is to this task;

When robot searches is to task, system is numbered according to the sequencing of robot searches to task, and for avoiding clashing when selecting robot, system selects robot according to the sequencing of mission number; Because task is a static amount, robot oneself cannot be selected to perform this task, therefore in each task, place m ant, replace the suitable robot of task choosing or Federation execution task with ant as dynamic factor; If the task representated by ant is loose type task, then single robot of Least-cost is selected to perform; If the task of ant representative is tight coupling type task, then this task need have been cooperated mutually by multiple robot, utilizes corresponding coalition formation algorithm to solve this task, selects suitable robot this task of composition Federation execution;

Suppose that this task is tight coupling type task, then need be completed by multiple robots collaborate, first m ant is positioned in n robot, select suitable robot mutually to cooperate according to ant group algorithm to execute the task, its Chinese style (1-1) represents that the probability of a wherein kth ant selection robot j is:

${\mathrm{\η}}_{ij}\left(t\right)=\frac{1}{d_{ij}}---(1-2)$

α is the weight of ant pheromones intensity on path, and β is the communication overhead weight between robot i to robot j, allow _krepresent the non-selected collection of bots of a kth ant, η _ijt () is the communication overhead intensity between robot i to robot j;

If when ant completes current robot selection, find that current formed multirobot alliance can perform this task, then ant stops seeking footpath, once circulates until m ant completes, and final one group of alliance of robot of alliance's Least-cost in this circulation of selecting is as current optimum solution; Carry out Pheromone update to the overall situation, more new formula is such as formula (1-3), (1-4), (1-5) simultaneously:

τ _ij(t+n)＝(1-ρ)×τ _ij(t)+Δτ _ij(t)(1-3)

${\mathrm{\Δ\τ}}_{ij}\left(t\right)=\underset{k=1}{\overset{m}{\Σ}}{\mathrm{\Δ\τ}}_{ij}^k\left(t\right)---(1-4)$

Wherein Cost _krepresent the cost that robot k pays when executing the task;

(2) task search flow process

The robot task of finishing the work search layer from following steps is searched for and task matching:

(1) robot of task matching layer is from initial position, random search task, and the search radius of robot is 10, if task is in robot searches radius, then represents and searches this task; Otherwise, then do not have;

(2) after robot searches to task, judge the type of task, if task is loose type task, then robot changes tasks carrying layer into and performs this task, jump procedure (6); If task is tight coupling type task, then go to step (3), issue cooperative information to other robot, select suitable composition alliance of robot, cooperation is finished the work mutually;

(3) in each tight coupling type task, place m ant, replace task with ant, utilize formula (1-1) to carry out probability selection, select the Federation execution task that the robot of Least-cost combination composition one is new;

(4) if current Ant Search to alliance of robot meet and perform the condition of this task, then stop search, then go to step (5); Otherwise go to step the next machine of (3) continuation searching to coalize;

(5) when m ant completes an interative computation, select that alliance of group robot of total Least-cost as optimum solution, and global information element is upgraded, shown in (1-3), (1-4), (1-5);

(6) search of finally finishing the work and Robot Selection, execute the task;

(3) task receiving layer

Multirobot alliance selected by after task receiving layer searches task by task search layer forms, and it is the executor of task; Task receiving layer is defined as two states: task idles state, state value S=0; Execution status of task, state value S=1; If robot is in S=0 state, represent that task search layer can be asked to the cooperation of its release tasks, and this robot meets the executive condition of task, then add in multirobot alliance and execute the task, robot forwards state 1 to by state 0; If S=1, then represent that this robot or alliance of robot are still in state of activation, then task search layer to its release tasks cooperation request, can not need wait for that it can accept other task requests after finishing the work; According to the different shape of task and the difference of robot cooperated form, be divided into following three kinds of forms by collaborative for multirobot: multirobot order is collaborative, multirobot synchronous synergetic, multirobot are freely worked in coordination with.

Described multirobot order collaborative strategy is based on how to select suitable robot to execute the task from alliance of robot, and be a kind of method based on cost and distance, its basic process is as follows: suppose robot R _icost when receiving task T, its unit distance consumed is A _i, robot R _ithe distance of motion is d _i, then robot R _itotal cost that this section of path consumes is as shown in formula (1-7):

Cost _k(i)=A _i× d _i(1-7) cost that robot consumes on each section of path is write down, by robot R ₁start to calculate cost summation when executing the task on each path, finally obtain the total cost on each path, and it is compared, select the composition alliance of robot on that minimum paths of cost summation jointly to work in coordination with this task; Suppose to perform this task by m robot, then before, (m-1) each robot cost summation is as shown in formula (1-8):

$Cost(m-1)=\underset{i=1}{\overset{m}{\Σ}}{A}_i\×d_i---\left(1-8\right)$

M robot performs these task cost public affairs such as formula shown in (1-9):

Cost(m)＝A _m×d _mT(1-9)

Total cost Cost is:

Cost＝Cost(m-1)+Cost(m)(1-10)

Wherein d _mTbe the distance of m robot to target location; Therefore, the cost set that an alliance n scheme of n robot composition forms is:

Cost=[Cost (1), Cost (2), Cost (3) ..., Cost (n)], this task of robot Federation execution selecting cost summation minimum from set Cost.

Described multimachine device synchronous collaboration refers to that the multiple robots in multirobot alliance receive multiple different task simultaneously, and each robot sets out to respective accepted task simultaneously; When each robot arrives respective accepted task location, analyze the ability of respective task, if wherein some member finds that its ability does not meet the executive condition of task, then it must send help information to other robot in alliance, plea for aid; If when there is other idle machines people in multirobot alliance, and the ability of idle machine people meets assistance condition, then idle machine people can assist the robot of scarce capacity to finish the work; If there is not other robot member in alliance to be in idle state, then must wait for that other robot is finished the work, assist the robot of scarce capacity to finish the work;

Multirobot synchronous synergetic strategy:

If multirobot alliance C is made up of m platform robot, its set is: R=[R ₁, R ₂, R ₃..., R _m], the Efficiency analysis corresponding to alliance C is: the Efficiency analysis of task is:, wherein there is n platform robot to receive task order, set out to respective task, arrive task Shi Ge robot and respective task ability is assessed; If find robot R _iability b _i<b _l, then represent that this robot capability does not meet the condition of finishing the work, must other robot be sought help from; If there is multiple stage robot in alliance to meet assistance condition, this robot is placed m ant, with robot R _iresiding position is that initial position carries out optimizing, and utilize the probability of ant group algorithm mechanism to select suitable robot to execute the task, its probability selection formula is such as formula shown in (1-11):

$P_i^k\left(t\right)=\frac{{\&lsqb;{\mathrm{\&tau;}}_i\left(t\right)\&rsqb;}^{\mathrm{\&alpha;}}\&times;{\&lsqb;{\mathrm{\&eta;}}_i\left(t\right)\&rsqb;}^{\mathrm{\&beta;}}}{\underset{s\&Subset;{\mathrm{allowed}}_k}{\&Sigma;}{\&lsqb;{\mathrm{\&tau;}}_i\left(t\right)\&rsqb;}^{\mathrm{\&alpha;}}\&times;{\&lsqb;{\mathrm{\&eta;}}_i\left(t\right)\&rsqb;}^{\mathrm{\&beta;}}},j\&Element;{\mathrm{allowed}}_k---\left(1-11\right)$

If ant seeks robot R _jshi Faxian can meet the executive condition of task, then stop search; Otherwise, continue search; Through Nc iterative search, select one group of alliance of robot assist people R of Least-cost _ifinish the work.

Described multirobot freely cooperates the free in the work environment search mission referring to that Zhong Ge robot of alliance is random, do not retrain by other robot, now each robot belongs to task search layer, and each robot is all independent individual in alliance, task will be caused to proceed because certain robot breaks down;

The free collaborative strategy of multirobot:

Suppose that all robot members in initial time multirobot alliance C are in free movement state, the ability radius of each robot searches task is r; As robot R _iwith task T _jdistance d _ijduring≤r, then represent robot R _isearch this task, robot R _ito this task T _jassess; If as robot R in alliance _iin place, T is taken office in search _j, then this robot will carry out role transforming, be tasks carrying layer from task search layer change; Robot R simultaneously _ito task T _janalyze, if this robot judges that this task is as loose type task, then independently performed by this robot; If this robot judges that this task is tight coupling type task, then in alliance, other members issue help information, wait for that other robot is assisted; System selects suitable robot to execute the task according to ant group algorithm, using Least-cost principle as selecting suitable robot Federation execution Mission Rules Guidelines; If when in alliance C, multiple stage robot searches multiple task simultaneously, the capacity of water according to robot location's distribution and each robot selects suitable assistance object.

Compared to traditional single robot manipulating task, multi-robot system of the present invention possesses following 6 advantages:

In the face of more complicated task, single robot is due to the limitation of its ability, and application is single, and multirobot is applied to multiple field by restructuring.

Too single compared to single robot function, multirobot can be applicable to perform more complicated task, the Task-decomposing of complexity is become some parts, has mutually been cooperated by multirobot.Compare single robot, it possesses rapidity and high efficiency.

The design of multirobot is compared to the unit people for a certain task design complexity, and its cost is lower, and design is easy, dirigibility is good, highly versatile, has expanded the application of robot.

Multi-robot system has that stronger redundance is strong, robustness and concurrency.

Can realize between multirobot intercoming mutually, carry out information sharing, effectively, rapidly can control the overall situation, realize quick position.

Multi-robot system is compared with single robot system, and its dirigibility is stronger, and system can be different according to task condition, take different tasks carrying schemes.

Below in conjunction with drawings and Examples, the invention will be further described.

Fig. 1 is task search layer random search task schematic diagram.

Fig. 2 is task search schematic flow sheet.

Tu3Shi robot executes the task path profile.

Fig. 4 is robot R under clear condition ₁independent execution schematic diagram.

Fig. 5 is robot R under clear condition ₁, R ₂collaborative schematic diagram of executing the task mutually.

Fig. 6 is robot R under clear condition ₁, R ₂, R ₃collaborative schematic diagram of executing the task mutually.

Fig. 7 has under obstacle condition to be executed the task separately schematic diagram by robot R1.

Fig. 8 is that under having barrier condition, robot R1, R2 work in coordination with schematic diagram of executing the task mutually.

Fig. 9 is that under having barrier condition, robot R1, R2, R3 work in coordination with schematic diagram of executing the task mutually.

Figure 10 is that under clear condition, robot R1, R2, R3 synchronously receive task schematic diagram.

Figure 11 is that under clear condition, robot R2 assist people R3 finishes the work schematic diagram.

Figure 12 is that under clear condition, robot R1, R2 assists R3 to finish the work schematic diagram.

Figure 13 has the robot task in idle robot situation to select schematic diagram.

Figure 14 is the cooperation sequential schematic of idle machine people R4 in alliance of robot lower left.

Figure 15 is the cooperation sequential schematic of idle machine people R4 in alliance of robot inside.

Figure 16 is that idle machine people R4 is in the top-right cooperation sequential schematic of alliance of robot.

Figure 17 is that under having barrier condition, robot R1, R2, R3 synchronous task accepts schematic diagram.

Figure 18 has the robot R2 under barrier condition to assist R3 to finish the work schematic diagram.

Figure 19 is that under having barrier condition, robot R1, R2, R3 receive task schematic diagram simultaneously.

Figure 20 has robot R4 under barrier condition to assist R1, R3 to execute the task schematic diagram.

Figure 21 Shi Ge robot random search task schematic diagram.

Figure 22 is that robot R2, R5 assists R1, R3 to assist R4 to execute the task schematic diagram.

Figure 23 is that robot R5, R2, R4 assists R6 to execute the task schematic diagram.

Embodiment

The task search of multirobot colony and a task executing method, comprising:

(1) task search layer strategy

Suppose that the position residing for the robot in task search layer is initial position, the node of initial position is S, robot is from initial position, random motion search task, the search radius r=10 of robot in alliance, if the task in environment and robot distance d are when [0,10], represent that robot searches is to this task;

When robot searches is to task, system is numbered according to the sequencing of robot searches to task, and for avoiding clashing when selecting robot, system selects robot according to the sequencing of mission number; Because task is a static amount, robot oneself cannot be selected to perform this task, therefore in each task, place m ant, replace the suitable robot of task choosing or Federation execution task with ant as dynamic factor; If the task representated by ant is loose type task, then single robot of Least-cost is selected to perform; If the task of ant representative is tight coupling type task, then this task need have been cooperated mutually by multiple robot, utilizes corresponding coalition formation algorithm to solve this task, selects suitable robot this task of composition Federation execution;

Suppose that this task is tight coupling type task, then need be completed by multiple robots collaborate, first m ant is positioned in n robot, select suitable robot mutually to cooperate according to ant group algorithm to execute the task, its Chinese style (1-1) represents that the probability of a wherein kth ant selection robot j is:

${\mathrm{\&eta;}}_{ij}\left(t\right)=\frac{1}{d_{ij}}---(1-2)$

α is the weight of ant pheromones intensity on path, and β is the communication overhead weight between robot i to robot j, allow _krepresent the non-selected collection of bots of a kth ant, η _ijt () is the communication overhead intensity between robot i to robot j;

If when ant completes current robot selection, find that current formed multirobot alliance can perform this task, then ant stops seeking footpath, once circulates until m ant completes, and final one group of alliance of robot of alliance's Least-cost in this circulation of selecting is as current optimum solution; Carry out Pheromone update to the overall situation, more new formula is such as formula (1-3), (1-4), (1-5) simultaneously:

τ _ij(t+n)＝(1-ρ)×τ _ij(t)+Δτ _ij(t)(1-3)

${\mathrm{\&Delta;\&tau;}}_{ij}\left(t\right)=\underset{k=1}{\overset{m}{\&Sigma;}}{\mathrm{\&Delta;\&tau;}}_{ij}^k\left(t\right)---(1-4)$

Wherein Cost _krepresent the cost that robot k pays when executing the task;

(2) task search flow process

The robot task of finishing the work search layer from following seven steps is searched for and task matching:

(1) robot of task matching layer is from initial position, random search task, and the search radius of robot is 10, if task is in robot searches radius, then represents and searches this task; Otherwise, then do not have;

(2) after robot searches to task, judge the type of task, if task is loose type task, then robot changes tasks carrying layer into and performs this task, jump procedure (6); If task is tight coupling type task, then go to step (3), issue cooperative information to other robot, select suitable composition alliance of robot, cooperation is finished the work mutually;

(3) in each tight coupling type task, place m ant, replace task with ant, utilize formula (1-1) to carry out probability selection, select the Federation execution task that the robot of Least-cost combination composition one is new;

(4) if current Ant Search to alliance of robot meet and perform the condition of this task, then stop search, then go to step (5); Otherwise go to step the next machine of (3) continuation searching to coalize;

(5) when m ant completes an interative computation, select that alliance of group robot of total Least-cost as optimum solution, and global information element is upgraded, shown in (1-3), (1-4), (1-5);

(6) search of finally finishing the work and Robot Selection, execute the task;

(3) task receiving layer

Multirobot alliance selected by after task receiving layer searches task by task search layer forms, and it is the executor of task; Task receiving layer is defined as two states: task idles state, state value S=0; Execution status of task, state value S=1; If robot is in S=0 state, represent that task search layer can be asked to the cooperation of its release tasks, and this robot meets the executive condition of task, then add in multirobot alliance and execute the task, robot forwards state 1 to by state 0; If S=1, then represent that this robot or alliance of robot are still in state of activation, then task search layer to its release tasks cooperation request, can not need wait for that it can accept other task requests after finishing the work; According to the different shape of task and the difference of robot cooperated form, be divided into following three kinds of forms by collaborative for multirobot: multirobot order is collaborative, multirobot synchronous synergetic, multirobot are freely worked in coordination with.

Multirobot order is collaborative is similar to logistics transportation, namely by a robot, task is passed to next robot, has mutually cooperated.Its premise calls ensures that in alliance of robot, each member can perform the task in certain limit, and alliance judges it is performed by a robot or mutually cooperated by multiple stage robot according to the task cost size of finishing the work.The ultimate principle that order is worked in coordination with is as follows: suppose that a multirobot alliance is made up of n platform robot, the set of its robot system is: R=[R ₁, R ₂, R ₃..., R _m], the cost set that Mei Tai robot pays in unit distance when executing the task is: A=[A ₁, A ₂, A ₃..., A _n].Suppose robot R ₁(i.e. the first robot) first receives task, has method in n to complete this task according to the known robot system of multirobot order Cooperation rule.Multirobot order Cooperation rule is formulated as follows, and i-th robot will participate in performing this task, then (i-1) platform robot before it must participate in the middle of the execution of this task.

As shown in Figure 3, the Federation execution task be made up of three robots.First by robot R ₁receive task, it has three kinds of methods performing this task.The first scheme, by robot R ₁this task of independent execution, goes directly to destination via path d14.First scheme, by robot R ₁with robot R ₂collaborate completes, and the d12 via path arrives destination through path d24, finishes the work.The third scheme is by robot R ₁, robot R ₂and robot R ₃mutually work in coordination with, eventually passed path d34 by path d1 through path d23 and arrive destination.The strategy how selecting robot to execute the task is one of robot cooperated research emphasis.

Described multirobot order collaborative strategy is based on how to select suitable robot to execute the task from alliance of robot, and be a kind of method based on cost and distance, its basic process is as follows: suppose robot R _icost when receiving task T, its unit distance consumed is A _i, robot R _ithe distance of motion is d _i, then robot R _itotal cost that this section of path consumes is as shown in formula (1-7):

Cost _k(i)=A _i× d _i(1-7) cost that robot consumes on each section of path is write down, by robot R ₁start to calculate cost summation when executing the task on each path, finally obtain the total cost on each path, and it is compared, select the composition alliance of robot on that minimum paths of cost summation jointly to work in coordination with this task; Suppose to perform this task by m robot, then before, (m-1) each robot cost summation is as shown in formula (1-8):

$Cost(m-1)=\underset{i=1}{\overset{m}{\&Sigma;}}{A}_i\&times;d_i---\left(1-8\right)$

M robot performs these task cost public affairs such as formula shown in (1-9):

Cost(m)＝A _m×d _mT(1-9)

Total cost Cost is:

Cost＝Cost(m-1)+Cost(m)(1-10)

Wherein d _mTbe the distance of m robot to target location; Therefore, the cost set that an alliance n scheme of n robot composition forms is:

Cost=[Cost (1), Cost (2), Cost (3) ..., Cost (n)], this task of robot Federation execution selecting cost summation minimum from set Cost.

Emulation experiment and analysis

(1) the multirobot order under clear environment is collaborative

When performing the task of same position when diverse location to robot in multirobot alliance respectively herein (Task), the collaborative selection between robot is studied.Suppose that a multirobot alliance is by robot R ₁, R ₂, R ₃composition, system to alliance issue first mission bit stream to robot R ₁, the cost size that alliance performs this task according to robot selects carrying into execution a plan of task.From table 1-1, represent robot R respectively ₁, R ₂, R ₃different schemes is selected to perform this task when different positions.

The collaborative costing analysis of multirobot order under table 1-1 clear condition

From table 1-1: when Zhong Ge robot of alliance is distributed in R ₁(10,50), R ₂(60,30), R ₃time (40,60), by robot R ₁to execute the task separately Least-cost; When Zhong Ge robot of alliance is distributed in R ₁(15,65), R ₂(40,40), R ₃(70,20), then by robot R ₁, R ₂mutual cooperation Least-cost; When Zhong Ge robot of alliance is distributed in R ₁(10,80), R ₂(30,50), R ₃(50,40), then by robot R ₁, R ₂, R ₃mutual cooperation Least-cost, its simulation result as shown in Figure 4,5, 6.It can thus be appreciated that when robot location in alliance changes, the strategy that robot executes the task also can change thereupon.

(2) there is the multirobot order under obstacle environment collaborative

Have studied the multirobot work compound under clear environment and routing above, this section is mainly studied alliance of robot under the environment having barrier to exist, how to be selected robot Federation execution task.Robot is when executing the task, and sensor detects the distance d<d of robot far from barrier _savetime, then robot is regularly to right rotation θ angle, and continues to move right safe distance S ₁, move to robot after safe distance and turn clockwise 90 ° and continue the S that moves ₂get back to the position of original motion, its formula is: S ₂=S ₁× tan θ, robot obstacle-avoiding as shown in figs. 1-7, horizontal direction represents S ₁, vertical direction represents S ₂.

By table 1-2 when robot is in R ₁(30,50), R ₂(80,40), R ₃known during (80,30) this three positions, by robot R ₁total Least-cost when executing the task separately, its routing as shown in figs. 1-7.Although robot R ₁to R ₂, R ₃between clear interference, and robot R ₁and there is barrier between impact point to disturb, find that robot is less than and R by the cost getting around barrier and finally consume after deliberation ₂, R ₃the cost paid during mutual cooperation, therefore alliance is selected by robot R ₁execute the task separately.As three robot R ₁(40,70), R ₂(60,50), R ₃when (90,30) are in this three positions, from table 1-2, by robot R ₁, R ₂cooperation Least-cost, its routing as shown in Figure 8.And when three robots are in three position R below ₁(40,70), R ₂(70,40), R ₃time (50,15), from table 1-2, by robot R ₁, R ₂, R ₃cooperated Least-cost, and its simulation result as shown in Figure 9.Simulation result shows, even if there is barrier between robot and task, robot also cooperates by avoiding obstacles, the optimum solution of final acquisition problem.

In sum, even if there is barrier between robot and task, robot can execute the task by getting around barrier, and its cost of consuming also may be less than the cost expended when mutually cooperating with the robot of other clears, and table 1-2 demonstrates the robot cooperation relation when there being barrier.

Table 1-2 has the collaborative costing analysis of multirobot order under barrier condition

Described multimachine device synchronous collaboration refers to that the multiple robots in multirobot alliance receive multiple different task simultaneously, and each robot sets out to respective accepted task simultaneously; When each robot arrives respective accepted task location, analyze the ability of respective task, if wherein some member finds that its ability does not meet the executive condition of task, then it must send help information to other robot in alliance, plea for aid; If when there is other idle machines people in multirobot alliance, and the ability of idle machine people meets assistance condition, then idle machine people can assist the robot of scarce capacity to finish the work; If there is not other robot member in alliance to be in idle state, then must wait for that other robot is finished the work, assist the robot of scarce capacity to finish the work;

Multirobot synchronous synergetic strategy:

If multirobot alliance C is made up of m platform robot, its set is: R=[R ₁, R ₂, R ₃..., R _m], the Efficiency analysis corresponding to alliance C is: the Efficiency analysis of task is:, wherein there is n platform robot to receive task order, set out to respective task, arrive task Shi Ge robot and respective task ability is assessed; If find robot R _iability b _i<b _l, then represent that this robot capability does not meet the condition of finishing the work, must other robot be sought help from; If there is multiple stage robot in alliance to meet assistance condition, this robot is placed m ant, with robot R _iresiding position is that initial position carries out optimizing, and utilize the probability of ant group algorithm mechanism to select suitable robot to execute the task, its probability selection formula is such as formula shown in (1-11):

$P_i^k\left(t\right)=\frac{{\&lsqb;{\mathrm{\&tau;}}_i\left(t\right)\&rsqb;}^{\mathrm{\&alpha;}}\&times;{\&lsqb;{\mathrm{\&eta;}}_i\left(t\right)\&rsqb;}^{\mathrm{\&beta;}}}{\underset{s\&Subset;{\mathrm{allowed}}_k}{\&Sigma;}{\&lsqb;{\mathrm{\&tau;}}_i\left(t\right)\&rsqb;}^{\mathrm{\&alpha;}}\&times;{\&lsqb;{\mathrm{\&eta;}}_i\left(t\right)\&rsqb;}^{\mathrm{\&beta;}}},j\&Element;{\mathrm{allowed}}_k---\left(1-11\right)$

If ant seeks robot R _jshi Faxian can meet the executive condition of task, then stop search; Otherwise, continue search; Through Nc iterative search, one group of alliance of robot assist people Ri of Least-cost is selected to finish the work.

Emulation experiment and analysis

(1) the multirobot synchronous synergetic under clear environment

When the member in alliance receives the task order of system issue simultaneously, set out to respective task, as shown in Figure 10, wherein cross symbol represents the ability that this robot is executed the task, triangle symbol represents that this robot does not possess the ability of executing the task, and demand helps other members in alliance.By the known robot R of table 1-3 ₁and R ₂all possesses assist people R ₃the ability of finishing the work, carries out probability selection according to ant group algorithm, and by shown in table 1-4, selects robot R ₂assist people R ₃cost is optimum, and simulation result as shown in figure 11.

Table 1-3 robot capability and task ability

1-4 assist people R ₃to execute the task cost

If as robot R ₂participate in central assistance still can not satisfy condition, then must continue search other robot and participate in assisting, each robot capability as shown in tables 1 to 5.

The table each robot capability of 1-5 and task ability

From table 1-5, the ability value of task 3 is 80, only has robot R in set ₁, R ₂.Therefore, by robot R ₁and R ₂common assist people R ₃just can finish the work, its simulation result as shown in figure 12.

If other robot is when executing the task, there is idle machine people in alliance, and this robot capability can meet assistance condition, then this robot of prioritizing selection assists to finish the work.Robot R in alliance as shown in figure 13 ₁and R ₃can not finish the work, need robot R ₄assistance completes, and wherein cross symbol represents that this robot can finish the work, and triangle symbol represents that this robot can not finish the work.

(2) the multirobot synchronous synergetic under obstacle environment is had

Having the multirobot synchronous synergetic under obstacle environment, when running into barrier when it is executed the task mode of motion collaborative with order in mode identical.By table 1-7 known current environment Xia Yousantai robot, in table, represent each robot capability and each task ability.As shown in Figure 17, robot R1, R2, R3 receive task T1, T2, T3 simultaneously, and set out to task, and run into barrier in the way that robot R1 executes the task, robot senses barrier in advance by sensor, in advance avoiding obstacles.In figure, cross symbol represents that this robot performs the ability of this task, triangle symbol represent this robot not tool perform the ability of this task.Need wait for that other robot is finished the work from table 1-7, robot R3 assists it to complete again.In table 1-7, robot R1 and R2 possesses this task ability of assistance, and according to minimum cost principle, shown in table 1-8, the final robot R2 assist people R3 that selects performs optimum, and simulation result as shown in figure 18.

Table 1-7 has each robot capability under barrier condition

Table 1-8 has the assist people R under barrier condition ₃to execute the task cost

As shown in figure 19, robot R ₁, R ₃ability do not meet the condition of executing the task, there is an idle machine people R in alliance of robot simultaneously ₄, and R ₄meet assist people R ₁, R ₃the ability of finishing the work, with the TSP problem of ant group algorithm for model, solves shortest path, final robot R ₄first assist people R ₁execute the task, then assist R ₃execute the task, its simulation result as shown in figure 20.

Described multirobot freely cooperates the free in the work environment search mission referring to that Zhong Ge robot of alliance is random, do not retrain by other robot, now each robot belongs to task search layer, and each robot is all independent individual in alliance, task will be caused to proceed because certain robot breaks down;

The free collaborative strategy of multirobot:

Suppose that all robot members in initial time multirobot alliance C are in free movement state, the ability radius of each robot searches task is r; As robot R _iwith task T _jdistance d _ijduring≤r, then represent robot R _isearch this task, robot R _ito this task T _jassess; If as robot R in alliance _iin place, T is taken office in search _j, then this robot will carry out role transforming, be tasks carrying layer from task search layer change; Robot R simultaneously _ito task T _janalyze, if this robot judges that this task is as loose type task, then independently performed by this robot; If this robot judges that this task is tight coupling type task, then in alliance, other members issue help information, wait for that other robot is assisted; System selects suitable robot to execute the task according to ant group algorithm, using Least-cost principle as selecting suitable robot Federation execution Mission Rules Guidelines; If when in alliance C, multiple stage robot searches multiple task simultaneously, the capacity of water according to robot location's distribution and each robot selects suitable assistance object.

Emulation experiment and analysis

Artificially routine with conveying robot herein, the search mission that robot is random in the place of 100 × 100, the ability radius of the search mission of robot is 10.Be the position distribution after each robot searches to task as shown in figure 21, wherein cross symbol represents that this robot searches is to task, and triangle represents that task is not sought by robot.Wherein show 1-9 and represent each robot capability in alliance C, table 1-10 represents the ability of each task.

Robot capability value in table 1-9 alliance

The ability value of each task of 1-10

As shown in Figure 21, robot R ₁, R ₄, R ₆search task T respectively ₁, T ₂, T ₃, due to robot R ₆be within the task search radius of robot with the distance of task, robot R ₆just task is searched at initial position.Shown in table 1-9 and table 1-10, robot R ₆ability do not meet the requirement of executing the task, need request help to other free-moving robots in alliance, according to minimum cost principle, utilize the probability selection mechanism of ant group algorithm, finally select by robot R ₂, R ₅assist people R ₁, robot R ₃assist R ₄execute the task as the optimum solution of problem, its simulation result as shown in figure 22.

The cost that the table each robot of 1-11 executes the task to task 3

Because in alliance, other robot is in execution status of task, R ₆need after original place waits for that other robot is finished the work, then it be assisted to complete.When other robot is finished the work, suitable robot is selected to execute the task, shown in table 1-11, when by robot R ₅, R ₂, R ₄cooperation robot R ₆least-cost, but robot R ₂, R ₃, R ₄ability can not meet the condition of executing the task, by contrast, finally by robot R ₅, R ₂, R ₄assist R ₆execute the task as the optimum of problem, its simulation result as shown in figure 23.

Claims (4)

1. the task search of multirobot colony and a task executing method, is characterized in that: comprising:

(1) task search layer strategy

Suppose that the position residing for the robot in task search layer is initial position, the node of initial position is S, robot is from initial position, random motion search task, the search radius r=10 of robot in alliance, if the task in environment and robot distance d are when [0,10], represent that robot searches is to this task;

When robot searches is to task, system is numbered according to the sequencing of robot searches to task, and for avoiding clashing when selecting robot, system selects robot according to the sequencing of mission number; Because task is a static amount, robot oneself cannot be selected to perform this task, therefore in each task, place m ant, replace the suitable robot of task choosing or Federation execution task with ant as dynamic factor; If the task representated by ant is loose type task, then single robot of Least-cost is selected to perform; If the task of ant representative is tight coupling type task, then this task need have been cooperated mutually by multiple robot, utilizes corresponding coalition formation algorithm to solve this task, selects suitable robot this task of composition Federation execution;

Suppose that this task is tight coupling type task, then need be completed by multiple robots collaborate, first m ant is positioned in n robot, select suitable robot mutually to cooperate according to ant group algorithm to execute the task, its Chinese style (1-1) represents that the probability of a wherein kth ant selection robot j is:

${\mathrm{\&eta;}}_{ij}\left(t\right)=\frac{1}{d_{ij}}---(1-2)$

α is the weight of ant pheromones intensity on path, and β is the communication overhead weight between robot i to robot j, allow _krepresent the non-selected collection of bots of a kth ant, η _ijt () is the communication overhead intensity between robot i to robot j;

If when ant completes current robot selection, find that current formed multirobot alliance can perform this task, then ant stops seeking footpath, once circulates until m ant completes, and final one group of alliance of robot of alliance's Least-cost in this circulation of selecting is as current optimum solution; Carry out Pheromone update to the overall situation, more new formula is such as formula (1-3), (1-4), (1-5) simultaneously:

τ _ij(t+n)＝(1-ρ)×τ _ij(t)+Δτ _ij(t)(1-3)

${\mathrm{\&Delta;\&tau;}}_{ij}\left(t\right)=\underset{k=1}{\overset{m}{\&Sigma;}}{\mathrm{\&Delta;\&tau;}}_{ij}^k\left(t\right)---(1-4)$

Wherein Cost _krepresent the cost that robot k pays when executing the task;

(2) task search flow process

The robot task of finishing the work search layer from following steps is searched for and task matching:

(1) robot of task matching layer is from initial position, random search task, and the search radius of robot is 10, if task is in robot searches radius, then represents and searches this task; Otherwise, then do not have;

(2) after robot searches to task, judge the type of task, if task is loose type task, then robot changes tasks carrying layer into and performs this task, jump procedure (6); If task is tight coupling type task, then go to step (3), issue cooperative information to other robot, select suitable composition alliance of robot, cooperation is finished the work mutually;

(3) in each tight coupling type task, place m ant, replace task with ant, utilize formula (1-1) to carry out probability selection, select the Federation execution task that the robot of Least-cost combination composition one is new;

(4) if current Ant Search to alliance of robot meet and perform the condition of this task, then stop search, then go to step (5); Otherwise go to step the next machine of (3) continuation searching to coalize;

(5) when m ant completes an interative computation, select that alliance of group robot of total Least-cost as optimum solution, and global information element is upgraded, shown in (1-3), (1-4), (1-5);

(6) search of finally finishing the work and Robot Selection, execute the task;

(3) task receiving layer

Multirobot alliance selected by after task receiving layer searches task by task search layer forms, and it is the executor of task; Task receiving layer is defined as two states: task idles state, state value S=0; Execution status of task, state value S=1; If robot is in S=0 state, represent that task search layer can be asked to the cooperation of its release tasks, and this robot meets the executive condition of task, then add in multirobot alliance and execute the task, robot forwards state 1 to by state 0; If S=1, then represent that this robot or alliance of robot are still in state of activation, then task search layer to its release tasks cooperation request, can not need wait for that it can accept other task requests after finishing the work; According to the different shape of task and the difference of robot cooperated form, be divided into following three kinds of forms by collaborative for multirobot: multirobot order is collaborative, multirobot synchronous synergetic, multirobot are freely worked in coordination with.

2. the task search of multirobot colony according to claim 1 and task executing method, it is characterized in that: described multirobot order collaborative strategy is based on how to select suitable robot to execute the task from alliance of robot, be a kind of method based on cost and distance, its basic process is as follows: suppose robot R _icost when receiving task T, its unit distance consumed is A _i, robot R _ithe distance of motion is d _i, then robot R _itotal cost that this section of path consumes is as shown in formula (1-7):

Cost _k(i)＝A _i×d _i(1-7)

Write down the cost that robot consumes on each section of path, by robot R ₁start to calculate cost summation when executing the task on each path, finally obtain the total cost on each path, and it is compared, select the composition alliance of robot on that minimum paths of cost summation jointly to work in coordination with this task; Suppose to perform this task by m robot, then before, (m-1) each robot cost summation is as shown in formula (1-8):

$Cost(m-1)=\underset{i=1}{\overset{m}{\&Sigma;}}{A}_i\&times;d_i---\left(1-8\right)$

M robot performs these task cost public affairs such as formula shown in (1-9):

Cost(m)＝A _m×d _mT(1-9)

Total cost Cost is:

Cost＝Cost(m-1)+Cost(m)(1-10)

Wherein d _mTbe the distance of m robot to target location; Therefore, the cost set that an alliance n scheme of n robot composition forms is:

Cost=[Cost (1), Cost (2), Cost (3) ..., Cost (n)], this task of robot Federation execution selecting cost summation minimum from set Cost.

3. the task search of multirobot colony according to claim 1 and task executing method, it is characterized in that: described multimachine device synchronous collaboration refers to that the multiple robots in multirobot alliance receive multiple different task simultaneously, each robot sets out to respective accepted task simultaneously; When each robot arrives respective accepted task location, analyze the ability of respective task, if wherein some member finds that its ability does not meet the executive condition of task, then it must send help information to other robot in alliance, plea for aid; If when there is other idle machines people in multirobot alliance, and the ability of idle machine people meets assistance condition, then idle machine people can assist the robot of scarce capacity to finish the work; If there is not other robot member in alliance to be in idle state, then must wait for that other robot is finished the work, assist the robot of scarce capacity to finish the work;

Multirobot synchronous synergetic strategy:

If multirobot alliance C is made up of m platform robot, its set is: R=[R ₁, R ₂, R ₃..., R _m], the Efficiency analysis corresponding to alliance C is: the Efficiency analysis of task is:, wherein there is n platform robot to receive task order, set out to respective task, arrive task Shi Ge robot and respective task ability is assessed; If find robot R _iability b _i<b _l, then represent that this robot capability does not meet the condition of finishing the work, must other robot be sought help from; If there is multiple stage robot in alliance to meet assistance condition, this robot is placed m ant, with robot R _iresiding position is that initial position carries out optimizing, and utilize the probability of ant group algorithm mechanism to select suitable robot to execute the task, its probability selection formula is such as formula shown in (1-11):

$P_i^k\left(t\right)=\frac{{\&lsqb;{\mathrm{\&tau;}}_i\left(t\right)\&rsqb;}^{\mathrm{\&alpha;}}\&times;{\&lsqb;{\mathrm{\&eta;}}_i\left(t\right)\&rsqb;}^{\mathrm{\&beta;}}}{\underset{s\&Subset;{\mathrm{allowed}}_k}{\&Sigma;}{\&lsqb;{\mathrm{\&tau;}}_i\left(t\right)\&rsqb;}^{\mathrm{\&alpha;}}\&times;{\&lsqb;{\mathrm{\&eta;}}_i\left(t\right)\&rsqb;}^{\mathrm{\&beta;}}},j\&Element;{\mathrm{allowed}}_k---\left(1-11\right)$

If ant seeks robot R _jshi Faxian can meet the executive condition of task, then stop search; Otherwise, continue search; Through Nc iterative search, select one group of alliance of robot assist people R of Least-cost _ifinish the work.

4. the task search of multirobot colony according to claim 1 and task executing method, it is characterized in that: described multirobot freely cooperates the free in the work environment search mission referring to that Zhong Ge robot of alliance is random, do not retrain by other robot, now each robot belongs to task search layer, and each robot is all independent individual in alliance, task will be caused to proceed because certain robot breaks down;

The free collaborative strategy of multirobot:

Suppose that all robot members in initial time multirobot alliance C are in free movement state, the ability radius of each robot searches task is r; As robot R _iwith task T _jdistance d _ijduring≤r, then represent robot R _isearch this task, robot R _ito this task T _jassess; If as robot R in alliance _iin place, T is taken office in search _j, then this robot will carry out role transforming, be tasks carrying layer from task search layer change; Robot R simultaneously _ito task T _janalyze, if this robot judges that this task is as loose type task, then independently performed by this robot; If this robot judges that this task is tight coupling type task, then in alliance, other members issue help information, wait for that other robot is assisted; System selects suitable robot to execute the task according to ant group algorithm, using Least-cost principle as selecting suitable robot Federation execution Mission Rules Guidelines; If when in alliance C, multiple stage robot searches multiple task simultaneously, the capacity of water according to robot location's distribution and each robot selects suitable assistance object.