Alexandre Gouskov

Numerical Modeling of Flexible Components for Assembly Path Planning Using a Virtual Reality Environment

The aspects of adequate simulation of the flexible parts for path planning during the Assembly/Disassembly (A/D) operation simulation are discussed in this paper. An interactive system forming two complementary levels and incorporating mechanical models of flexible part is described. The approach proposed will be used as a basis to the simulation of flexible parts into a Virtual Reality (VR) environment for the A/D evaluation. First of all, the study of current assembly path planning systems is performed. Secondly, as an issue of the problems discussed, a new system integrating real-time and interactive mechanical simulation approaches is proposed. Finally, an example of the interactive mechanical behavior model applicable to flexible rods used into an A/D path planning context is presented. Numerical modeling focuses on typical boundary conditions. The present approach is considered as a proposal for a methodology used with VR environments during the product design process.Copyright

Analysis of Indirect Measurement of Cutting Forces Turning Metal Cylindrical Shells

Cutting forces measurement is an important component of the machining processes development and control. The use of conventional direct measurement systems is often impossible as they interfere in the process’s dynamics. This work proposes a method of cutting force indirect estimation during turning thin-walled cylindrical shells. Calculation of the flexibility matrix has enabled us to relate measured displacements of certain workpiece’s points to the cutting force. An optimization approach for choosing the measurement points location has been proposed, based on the best conditioning of the flexibility matrix.

Determination of Input Data for Realistic Assembly Operation Simulation of Flexible Beam Parts in a Virtual Reality Environment

Different studies are required during the design process to improve the performance and quality of complex mechanical systems. Such systems usually contain deformable parts, which complex behavior is a critical factor that must be taken into account during the design, assembly/disassembly (A/D), ergonomics evaluations of a product. Virtual Reality (VR) proposes the designer specific functions to study efficiently complex systems: interaction with a virtual part, visual/force feedback, real-time multi criteria analysis of A/D. However, the quality of virtual simulations like A/D of flexible parts depends on input data. The aim of this work is to discuss main input data required for realistic simulations of virtual A/D of flexible parts. Some input parameters are used by a behavior model of flexible beams coupled to virtual A/D. The incorporation of mechanical models implies the use of material properties, which are hard to set up for multi-material flexible parts. This paper proposes a method to determine quickly a material characteristic of such parts for realistic virtual A/D simulations. Examples of law behavior definition as well as A/D simulation of a flexible part using the proposed approach are presented.Copyright

Towards position feedback control interfaces: application to a virtual assembly of flexible parts

Virtual assembly/disassembly (A/D) study during the product design is an important aspect to improve the performance and quality of products. Usually, existing virtual reality (VR) systems allow to simulate the A/D operations of rigid parts. However, it is difficult to model accurately the virtual A/D operations of flexible parts given their complex behavior. The aim of this work is to analyze current VR interfaces for their application in A/D of flexible parts. Current VR devices are mainly restricted to the specification of geometric input data for virtual A/D. This is not physically correct from the point of view of users action generation and does not take into account particularities of flexible parts behavior. To this end, different experiments have been performed to justify some limits of the use of current VR devices in realistic flexible part simulation. The necessity of position control device development is justified to supply satisfactory results during the A/D of flexible parts.

Proposal of Criteria Characterizing Assembly Operations of Flexible Beam Parts for Virtual Reality Applications

Fast simulation of Assembly/Disassembly (A/D) operations is important to improve quickly the performance and quality of products. However, it is difficult to model accurately the A/D operations of products containing flexible parts given their complex mechanical behavior. To evaluate the A/D of flexible parts in order to provide better responses in terms of design, maintenance, ergonomics, a user needs criteria characterizing A/D operations. The aim of this work is to propose some of these criteria based on geometric and physical parameters. The realistic values of these parameters are coupled to an adequate behavior model of flexible parts and can be used in virtual A/D simulations. So, as an issue of current A/D approach problems, the requirements for integration of the Interactive Mechanical Model (IMM) into a virtual A/D system are discussed. An example of flexible beam IMM providing the realistic data is presented. The use of non-linear IMMs raises questions regarding the boundary conditions required to model a user’s action during a virtual A/D operation simulation. To this end, physical and numerical experiments have been performed using an optical tracking system. From these experiments, the necessary parameters can be extracted to characterize both real and virtual A/D operations.Copyright