Design Analysis Of Compliant Mechanism For Real-time Deformation Visualization And Haptic Feedback

Haptic technology, which has introduced the effect of "humun" to the traditional robot field, could provide feedback force to enable designers to experience the deformation in virtual environment. This advanced technology is generated combining multi subjects, including computer science, computer graphics, automation technology, information technology, robots and man-controled robot technology. And it has been widely introduced to computer aided design, computer aided surgery and computer aided assembly, etc. Real-time visulization feedback is required to allow designers manuscript successfully in the virtual world. In this paper, instead of addressing a specific application of haptic simulation, we address the bottleneck problem of real-time interaction with large global deformations of3D compliant mechanism, with real-time visualization and physically realistic force feedback.This dissertation presents the computational models and design analysis of compliant mechanism for real-time deformation visualization and haptic evaluation. The organization structure of the full thesis is as follows:Chapter1introduces the background and development prospect of haptic technology and summarizes the current research status for compliant mechanism, which leads to the necessity and application background of compliant mechanism for real-time deformation visualization and haptic evaluation. Then it proposes this thesis’research purpose, significance and main research content.Chapter2proposes comparative compliant mechanism models in local coordinate and global coordinate, respectively. The curvature-based model utilized curvature which is independent of coordinate to describe the curve’s bending and twisting characteristic, and the geometrical deformation is comprehensively expressed. The compliant mechanism modeling is established in contrast, including oreintation, twisting angle, displacement and mechanics information. The deformation modelings are completed in two different coordinate.Chapter3presents a general formulation of a reduced-order discrete state space model and its solution as a function of path lengths for a3D curvature-based beam model (CBM). The state-space representation decouples the13th order CBM into two sets of reduced-order ordinary differential equations; the first solves for the orientation and moment whereas the second describes the deformed beam shape. Thus, it enables parallel computation of the deformed shape from the solutions to the orientation and moments. Thus it can acquire the real-time computation for simultaneous real-time visualization and force/torque feedback for manipulating of compliant mechanisms.Chapter4investigates the parametric effects on the force/deflection relationship governing the assembly/disassembly processes of a snap-fit for developing embedded algebraic solutions to achieve realistic force feedback through a haptic device. An algebraic model, which isolates individual parametric factors that contribute to the cantilever hook deflection, has been derived for examining assumptions commonly made to simplify models for design optimization and real-time control. And the ANSYS FEA simulation and contact-based non-linear CBM have been utilized for the same problem.Chapter5proposes the compliant mechanism deisgn with the haptic feedback evaluation. Users can evaluate the reaction force in virtual environment. The position of Phantom stylus as carrier for moving object is detected in high frequency (1KHz). The feedback forces for different cantilever design options have been recorded while experienced by users with the assistance of SensAble Phantom haptic device. A ball-joint-like spherical motor capable of offering smooth, continuous multi-DOF motion is presented as an alternative design for haptic applications. With a two-mode configuration, this device can be operated as a joystick manipulating a target in six degrees-of-freedom (DOF), and provides realistic force/torque feedback in real-time.Chapter6puts forward to two illustrative application examples. The state-space formulation and real-time computation method have been applied to analyze two flexible mobile-sensing node (FMN) designs. The new design, which overcomes several kinematic limitations and practical implementation problems commonly encountered in FMN navigation in tight3D space, permits bending and twisting of the compliant beam in3D space. The discrete linear CBM for the FMN design achieves real-time visualization for moving FMN. The second example demonstrates the effectiveness of the cantilever hook model as embedded algebraic solutions for haptic rendering in design. Implemented on a commercial Phantom haptic device, several individuals participated in evaluating a set of design options with different parameters settings; these findings demonstrate that the design confidence of assembly robustness can be enhanced through a relatively accurate virtual force feedback. And further more, the disassembly process of a snap-fit is simulated, where the two-mode permanent magnet spherical motor haptic device is incorporated as an interfacing device that receives motion commands from a virtual design environment and delivers torque feedback to the designer/user.Chapter7summarizes the paper’s main research content and innovation points, puts forward some research directions can be further improved.In summary, the real-time computing of the compliant mechanism provides a good foundation for research and development of a haptic technology in compliant mechasim system.