Automatic generation of robot and manual assembly plans using octrees

This paper aims to investigate automatic assembly planning for robot and manual assembly. The octree decomposition technique is applied to approximate CAD models with an octree representation which are then used to generate robot and manual assembly plans. An assembly planning system able to generate assembly plans was developed to build these prototype models. Octree decomposition is an effective assembly planning tool. Assembly plans can automatically be generated for robot and manual assembly using octree models. Research limitations/implications - One disadvantage of the octree decomposition technique is that it approximates a part model with cubes instead of using the actual model. This limits its use and applications when complex assemblies must be planned, but in the context of prototyping can allow a rough component to be formed which can later be finished by hand. Assembly plans can be generated using octree decomposition, however, new algorithms must be developed to overcome its limitations

Gluing free assembly of an advanced 3D structure using visual servoing.

International audienceThe paper deals with robotic assembly of 5 parts by their U-grooves to achieve stables 3D MEMS, without any use of soldering effect. The parts and their grooves measure 400 m 400 m 100 m 1.5 m and 100 m 100 m 100 m 1.5 m leading to an assembly clearance ranging from -3 and +3 m. Two visual servo approaches are used simultaneously: 2D visual servo for gripping and release of parts and 3D visual servo for displacement of parts. The results of experiments are presented and analyzed

Robot planning based on boolean specifications using petri net models

In this paper, we propose an automated method for planning a team of mobile robots such that a Boolean-based mission is accomplished. The task consists of logical requirements over some regions of interest for the agents'' trajectories and for their final states. In other words, we allow combinatorial specifications defining desired final states whose attainment includes visits to, avoidance of, and ending in certain regions. The path planning approach should select such final states that optimize a certain global cost function. In particular, we consider minimum expected traveling distance of the team and reduce congestions. A Petri net (PN) with outputs models the movement capabilities of the team and the regions of interest. The imposed specification is translated to a set of linear restrictions for some binary variables, the robot movement capabilities are formulated as linear constraints on PN markings, and the evaluations of the binary variables are linked with PN markings via linear inequalities. This allows us to solve an integer linear programming problem whose solution yields robotic trajectories satisfying the task

Survey on assembly sequencing: a combinatorial and geometrical perspective

A systematic overview on the subject of assembly sequencing is presented. Sequencing lies at the core of assembly planning, and variants include finding a feasible sequence—respecting the precedence constraints between the assembly operations—, or determining an optimal one according to one or several operational criteria. The different ways of representing the space of feasible assembly sequences are described, as well as the search and optimization algorithms that can be used. Geometry plays a fundamental role in devising the precedence constraints between assembly operations, and this is the subject of the second part of the survey, which treats also motion in contact in the context of the actual performance of assembly operations.Peer ReviewedPostprint (author’s final draft

New bottom-up algorithm for assembly plan generation : opportunities for micro-factory design.

International audienceThis paper discusses a new approach dedicated to assembly plan generation, called "bottom-up algorithm". It is compared to the traditional "top-down approach", usually used to perform this stage of the design process of the assembly systems for "macro-products". We explore why this new algorithm is better adapted for designing a microassembly system. The case of watch assembly plans generation is described through the both approaches and the obtained results are compared