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Automated synthesis of computer-aided assembly planning (CAAP) processes is a crucial task for engineering practice and design theory. It is of especial relevance for modern robotic industries, which need in technological assembly instructions to be described in-depth and in-detail as much as possible. The assembly sequence is a key design decision on which many operational properties of the product and economic characteristics of production depend.Choosing a rational assembly sequence planning (ASP) is a challenge. It requires significant computing resources and taking into consideration a large number of technical parameters and economic characteristics that affect the quality of design alternatives. Insights into the quality of alternatives are given as the expert’s preferences rather than as the numerical criteria.The abovementioned features do not allow us to apply the classical optimization methods or mathematical programming for making ASP decision. For this, most modern publications offer various search engine optimization methods based on biological and behavioral analogies. In this paradigm, it is believed that a set of acceptable alternatives that form the original choice space is a priori known. In most design situations this presumption is unrealistic.In engineering practice, considerable technological knowledge about the assembly of products for different function purposes is gained. These are mostly ad hoc data that exist in the form of rules, recommendations, recipes, heuristics, expert preferences, descriptions of successful precedents, etc. The paper suggests a new method for a choice of the rational assembly sequence based on the use of the decision theory apparatus. The proposal contains formalization of important design and technological heuristics, namely consistency with the dimensional chain system, geometric “freedom” during assembly, monotony in size, weight, accuracy, etc.A set of choice functions is open and can be completed by additional choice functions that describe engineering heuristics and decision rules that are relevant in the given design situation. The proposed approach allows the assessment and choice of alternatives according to several aspects or criteria. To do this, it is possible to use various methods of generating a common choice function from the totality of particular functions.

Computer aided assembly planning (CAAP) of complex products is an important and urgent problem of state-of-the-art information technologies. A configuration of the technical system imposes fundamental restrictions on the design solutions of the assembly process. The CAAP studies offer various methods for modelling geometric constraints. The most accurate results are obtained from the studies of geometric obstacles, which prohibit the part movement to the appropriate position in the product, by the collision analysis methods. An assembly of complex technical systems by this approach requires very high computational costs, since the analysis should be performed for each part and in several directions.The article describes a method for minimizing the number of direct checks for geometric obstacle avoidance. Introduces a concept of the geometric situation to formalize such fragments of a structure, which require checking for geometric obstacle avoidance. Formulates two statements about geometric heredity during the assembly. Poses the task of minimizing the number of direct checks as a non-antagonistic two-person game on two-colour painting of an ordered set. Presents the main decision criteria under uncertainty. To determine the best criterion, a computational experiment was carried out on painting the ordered sets with radically different structural properties. All the connected ordered sets are divided into 13 subclasses, each of which includes structurally similar instances. To implement the experiment, a special program has been developed that creates a random ordered set in the selected subclass, implements a game session on its coloration, and also collects and processes statistical data on a group of the homogeneous experiments.The computational experiment has shown that in all subclasses of the partial orders, the Hurwitz criterion with a confidence coefficient of 2/3 and that of Bayes-Laplace demonstrate the best results. The Wald and Savage criteria have demonstrated the worst results. In the experiment, a difference between the best and worst results reached 70%. With increasing height (maximum number of levels) of an ordered set, this difference tends to grow rapidly. In the subclass of pseudo-chains, all criteria showed approximately equal results.The game model of geometric obstacles avoidance allows formalizing data on geometric heredity and obtaining data on the composition and the minimum number of configurations, the test of which objectifies all existing-in-the-product geometric constraints on the movements of parts during assembly.

The derivation of product features and assembly process characteristics from CAD data is typically manually performed by experienced design engineers. This paper presents an approach for systematic feature detection from CAD data with identification of a product liaison matrix and the corresponding assembly sequence. The results are stored in AutomationML exchange file format to be used in the subsequent step of automatic workplace design based on the idea of optimized resource to process allocation by heuristic search. The approach is demonstrated and validated using an application example of three different lot size scenarios. [ABSTRACT FROM AUTHOR]

Today the assembly sequence for the products is often carried out manually and its definition, typically, is very expensive, not guaranteeing optimal solutions. Coming up with an efficient assembly sequence is the essential step to improve process productivity and reduces the time and costs related to assembly machines and equipment. The issue related to the assembly sequence of a product depends on the total number of the its components. In particular, the number of the possible sequences can be obtained through the calculus of the factorial of the number of the product components. This work presents an automatic approach intended to define assembly sequences, based on the information regard the contacts and the interferences existing among the components, which is obtained by the assembly CAD model of the product. The level of the information required by this approach allows its implementation at early stages of design, as soon as the layout of the conceptual solution of the product is defined, independently by the method used to model the CAD assembly. The procedure proposed is focused to obtain a reduced number of assembly sequences, guaranteeing that there is at least one feasible assembly sequence among them. The procedure is oriented to iteratively identify independent and important subassemblies into the CAD assembly, then merge them to specific assembling nodes and generate sequences until the whole product is analyzed. After a brief review of current methodologies developed for assembly planning, in this paper, the automated procedure for assembly sequence generation is explained and applied on an example, obtaining feasible solutions. [ABSTRACT FROM AUTHOR]