Robotic Assembly Process Research Articles

Random exploration strategy: A new paradigm in robotics. A comparison with determinist approaches

This paper presents the latest results of a joint research project involving the Institute of Microengineering of the Swiss Federal Institute of Technology (Switzerland) and the Industrial Automation Laboratory of the Lyon National Institute of Applied Sciences (France). This project consists in the implementation of a robotic assembly method for chamferless parts by using a very fast parallel robot called DELTA. The paper recalls the main features of the system in order to focus on the experimental evaluation of different search strategies employed to absorb misalignment between pieces, paying particular attention to the comparison of the mean search time of random and deterministic trajectories (such as random, Lissajous' and spiral trajectories) as a function of the clearance of parts. The experimental results obtained in this work show a better performance of the random strategy and stress the benefits of adopting a stochastic approach to design and implement open-loop control strategies for robotic assembly processes.

Evaluation of exploration strategies in robotic assembly

We present in this paper the latest results of a joint research project involving the Institute of Microengineering of the Swiss Federal Institute of Technology (Switzerland) and the Industrial Automation Laboratory of the Lyon National Institute of Applied Sciences (France). This project consists in the implementation of a robotic assembly method for chamferless parts by using a very fast parallel robot called DELTA. The paper recalls the main features of the system in order to focus on the experimental evaluation of different search strategies employed to absorb misalignment between pieces, paying a particular attention to the comparison of the mean search time of random and deterministic trajectories (such as random, Lissajous’ and spiral trajectories) as a function of the clearance of parts. The experimental results obtained in this work show a better performance of the random strategy and stress the benefits of adopting a stochastic approach to design and implement open-loop control strategies for robotic assembly processes.

Modelling and sequence generation for robotized mechanical assembly

This paper describes a programming system capable of automatically generating robotic assembly sequences. It is a generative robotic assembly process planner. A geometric model of the product to be assembled is defined interactively in the feature-based product database. Assembly relationships among components are modelled interactively in the graphical relation diagram. The validity of the physical connections defined in the relation diagram is checked by analyzing the geometric information contained in the feature-based product database. A single robotic assembly sequence is automatically generated. The component (or subassembly) to be moved at each step of the assembly sequence is also explicitly provided in the assembly sequence formulation.

Automatic generation of robotic assembly sequences

This paper describes a programming system capable of automatically generating robotic assembly sequences. It is a generative robotic assembly process planner. A geometric model of the product to be assembled is defined interactively in the feature-based product database. Assembly relationships between components are modelled interactively in the graphical relation diagrams. An initial and a final relation diagram are used to describe the initial and final states of the assembly, respectively. The validity of the physical connections defined in the final relation diagram is checked by analysing the information contained in the feature-based product database A single robotic assembly sequence is generated automatically, using only the relational data defined in the final relation diagram. Subassemblies are generated automatically. The component (or subassembly) to be moved at each step of the sequence is also explicity provided in the assembly-sequence formulation.

Noncontact Bent Pin Detection Using Laser Diffraction

The use of optical diffraction is investigated to detect bent pins on a high-density multi-chip integrated-circuit module as an intermediate step in a robotic assembly process. A fixed laser beam shines on a fixed optical array while the robot moves the pins of the module through the beam at four different orientations. (While two scans are mathematically adequate, four scans are required because of the physical characteristics of this particular module.) The optical array is continuously scanned and the resultant images are processed to detect specific abnormalities in the diffraction pattern. If a flaw is detected, software determines the approximate location of the defective pin and whether it should be straightened manually or sent back for rework (determined by the angle of bend).

A framework for the robotic assembly of parts with general geometries†

This is a sequel of a paper entitled: ‘A framework for the economic evaluation of production system and product design alternatives for robot assembly’ (AbdelMalek and Boucher 1985). The previous work introduced guidelines for the robotic assembly of a ‘peg-in-a-hole’. This paper extends the previous work to cover the robotic assembly of parts with general geometries. The paper analyses the effect of the diiferent parameters involved in the robotic assembly process on its feasibility.