CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of priority from Chinese Patent Application No. 202010791643.8, filed on Aug. 7, 2020. The content of the aforementioned applications, including any intervening amendments thereto, is incorporated herein by reference in its entirety.

TECHNICAL FIELD

The present invention relates to the technical field of task collaboration, in particular to a takt system and method for the collaboration of production processes with uncertain time.

BACKGROUND OF THE PRESENT INVENTION

In the context of novel manufacturing mode and market environment, the customer demand presents a personalized trend of single-piece and small-batches. Manufacturing resources were organized statically within the enterprise, but now they are transformed into dynamic organization in the form of manufacturing services in the global market. Production processes for accomplishing the customer demand are transferred from a single enterprise to a plurality of enterprises. Each service provider undertakes a part of the production task. These changes have an impact on measuring the efficiency of the production process. Throughput which is commonly used in the mass production is not applicable to measure the efficiency of the single-piece small-batch production processes. Because the service providers are distributed in multiple places, it is not enough to only focus on the completion time of the customer demand, but also necessary to take the collaboration efficiency of the production process into consideration.

Many scholars have analyzed the influencing factors of the collaboration efficiency from different aspects and have illustrated the source of production time uncertainty and its description method. A majority of studies mainly focus on result-oriented indices such as total completion time. For example, earliest start time, latest start time or most possible start time are used as reference to organize and control the time so as to achieve the shortest total completion time.

However, the existing method lacks systematic description for the factors, and does not consider the influence of uncertainty degree, completion probability and other factors on collaboration efficiency. In the aspect of the measurement of collaboration efficiency, most of the researches including various time collaboration control methods focus on result-oriented indices such as total completion time, ignoring the measurement of process efficiency such as the degree of wasted time in the service processes, which lack process-oriented indices on collaboration efficiency. The combination of optimized models with simulation method and intelligent algorithms is an effective means to solve the time collaboration problem with uncertainty and also provides a study basis to the present invention. However, in the existing studies, whether a specified distribution or general distribution is used to express the production time, production time must be subject to the same type of distribution, which lacks comprehensive consideration for different production tasks with different types of time distribution functions.

SUMMARY OF THE PRESENT INVENTION

(I) Technical Problems

Aiming at the disadvantages of the prior art, the present invention provides a takt system and method for the collaboration of production processes with uncertain time, which solves the problem in the prior art that the impact of factors such as uncertainty degree, task completion probability and the like on collaboration efficiency is not considered.

(II) Technical Solutions

In order to achieve the above purpose, the present invention is implemented through the following technical solutions:

A takt system and method for the collaboration of production processes with uncertain time includes:

Acquiring information of collaborative production tasks;

Based on the information of the collaborative production tasks, establishing a takt control model for the collaboration of production processes targeting at minimizing the estimated wasted time, wherein the takt control model includes an objective function and constraints;

Solving the takt control model, and outputting a set of time intervals with the minimal estimated wasted time as a takt ST;
ST={[SS1,SE1], . . . ,[SSi,SEi], . . . ,[SSn,SEn]}

SS is the set start time of a task; SE is the set end time of a task; i is a serial number of the task and a service provider; and n is the quantity of tasks and service providers.

Further, the information of the collaborative production tasks includes a service structure, distribution functions of production time and historical wasted time of each task.

Further, the information of the collaborative production tasks also may include a service structure, distribution functions of production time and historical wasted time of each task and task completion probability.

Further, the objective function is:
min θe=minE[Σi,j=1,(i,j)∈Anθiθj|SSj−di|/n];θ indicates historical wasted time, and a calculation formula is
θ=Σi,j=1,(i,j)∈An|SSj−di|/n;

θeindicates estimated wasted time, and a calculation formula is
θe=E[Σi,j=1,(i,j)∈Anθiθj|SSj−di|/n];

A indicates a set of directly adjacent service pairs;

d indicates an actual end time of the task.

Further, the constraints may be:

s0=d0=0di=si+tisj=max⁢{SSj,max(i,j)∈A⁢(di)}dn+1=sn+1=max(i,n+1)∈A⁢(SEi)≤DSSj≥SEi,∀(i,j)∈ASSi,SEi≥0SEi>SSi

s is the actual start time of a task; t is the production time for the service provider to complete the task; A is the set of directly adjacent service pairs; and D is a completion deadline of a customer demand.

Further, the constraints may also be:

s0=d0=0di=si+tisj=max⁢{SSj,max(i,j)∈A⁢(di)}dn+1=sn+1=max(i,n+1)∈A⁢(SEi)≤DSSj≥SEi,∀(i,j)∈APr⁢{ti≤SEi-SSi}≥pSEi>SSi

s is the actual start time of a task; t is the production time for the service provider to complete the task; A is the set of directly adjacent service pairs; D is the completion deadline of the customer demand; p indicates the task completion probability; and Pr{ } is a probability function.

Further, the distribution functions of production time include: a normal distribution N(μ, σ2) with mean value of μ and variance of σ2, uniform distribution Uniform(a, b) in an interval [a, b] or triangle distribution Triangle(a, m, b) with a modal number of m in the interval [a, b].

Further, in the step of solving the takt control models, a particle swarm optimization algorithm embedded with Monte Carlo Simulation is used, which is specifically as follows:

An objective function value corresponding to each set of time intervals is calculated by Monte Carlo Simulation as fitness of the particle swarm optimization algorithm, then the particle swarm optimization algorithm is used to optimize and solve the problem, and finally the set of time intervals with the minimal estimated wasted time, i.e. the takt is obtained.

In the second aspect, the present invention provides a takt system and method for the collaboration of production processes with uncertain time. The system includes a memory, a processor, and computer programs stored on the memory and capable of running on the processor. The processor implements the steps of the above method when executing the computer programs.

(III) Beneficial Effects

The present invention provides the takt system and method for the collaboration of production processes with uncertain time. Compared with the prior art, the present invention has the following beneficial effects:

The present invention measures the collaboration efficiency of the production processes with indices such as the estimated wasted time and calculates the estimated wasted time by the expectation of the weighted sum of wasted time; and faced with the collaborative production process with uncertain time, the propagation of uncertainty factors and occurrence of wasted time in the collaborative production processes are limited in a manner of takt. Orientating two different scenarios focusing on the collaboration efficiency of the production processes and the task completion probability, two takt control models are established, and takt solutions for the collaboration of production processes with uncertain time are obtained by solving the models. Compared with the prior art using the earliest start time, latest start time and most possible start time as references to organize and control the time, the present invention can reduce the wasted time in the collaborative production process, realize higher process efficiency, and reduce the difficulty for obtaining the effective time control solution. Compared with the time control technology with time buffer, the present invention limits the propagation of the uncertainty at each production task through the takt, which has higher robustness, and can provide better time guidance to the service providers.

