An Efficient Method of Assembly Path Planning in Virtual Manufacturing System

Abstract

With the development of information technology, such as CAD, CAPP and CAM, assembly process, which accounts for large amount of time and cost of manufacturing, to be included in virtual manufacturing system is urgently required. According to the principle that the sequence and path in assembly and disassembly process are reversible, the assembly path can be obtained on the basis of assembly constraints analysis and information model building through optimized and reversed. The method of assembly path planning presented in this paper can effectively reduce computational complexity and improve planning efficiency, whose correctness and efficiency is proven by an application example.

Review and taxonomies of assembly and disassembly path planning problems and approaches

“…Accordingly, some smoothing procedures have been employed to increase the clearance and smoothness of the initial path, as in [45,56]. Also, minimizing the number of orientation changes of the assembler in the process of assembly can reduce the complexity of manipulation [38,51,57]. Another objective functions that is specific to the DAPP problem is maximizing the distance of a disassembled part from the remaining subassembly, as mentioned in [40,58,59].…”

“…Then the intersection of feasible disassembly directions for all mating faces yields the resultant disassembly direction(s) for that part. Gao et al presented an interference-detecting method for determining the disassembly path of a particular part p k in an assembly [57]. First, the bounding box contour of the whole assembly is calculated using the initial configurations of all parts.…”

“…Minimizing path length [35,[51][52][53] Maximizing safety of paths [31,54,55] Maximizing path smoothness [45,56] Minimizing number of orientation changes of parts [38,51,57] Minimizing inter-part penetrations [64] Maximizing distance of a disassembled part from the remaining subassembly [40,58,59] …”

“…Separating Directions [67] Removing parts of a model aircraft combustion engine (12) ind C NS M NL C [71] Extracting: a cube from a table (2), a cube from a tetrahedron (2) puz C S NM NL C Extracting a spacer from a side-plate (2) ind [73] Removing parts of: a tilted blender (7), a Discriminator (11), a crate (5) ind C S M L C [74] Removing parts of: a model aircraft combustion engine (42) an electric bell (22) ind C S M NL I [57] Removing the parts of a reduction gearbox (9) ind C S M L C [88] Generating the exploded view of a cylinder gear reducer (94) ind C S M L C [20] Removing the parts of: a simplified car model (8), a lifting device (5), a flange coupling (6) and a heel pad clamp (14) ind C NS NM L I [90] Removing parts of a Washer (20) ind C S M L C Swept Volume [38] Removing parts of a component of the center wing of an aircraft (731) ind C S M L I [72] Removing parts of fore flap of an aircraft (80) ind C S M L I [87] Removing parts of an automotive generator (17) ind C S M L C Motion space [17] N/A N/A C S M L C [65] Removing parts of a diagonal star puzzle (6) puz C NS M L C [77] Removing parts of: an aircraft model (32), a headlight (33), a car chassis (73) ind C S M L C Removing parts of a cube (10) puz Cell Decomposition [49] Moving through: a scene with large free-space area (10) complex CAD models with narrow passages puz PRC S M L I…”