Characteristic Analysis and Optimization of a Four-bar Compliant Mechanism with Single Flexible Member

The characteristics and optimization analysis of a four-bar compliant mechanism with one flexible member (or flexible joint) are carried out. Firstly, based on the pseudo-rigid body model theory of the compliant mechanism, the kinematics relationship, system kinetic energy and potential energy of the general four-bar compliant mechanism are analyzed, and the dynamic model of the four-bar compliant mechanism is established by using Lagrange's equation. Secondly, through the creation of the energy equation of the four-bar compliant mechanism and the analysis of the first and second derivatives of the input variables, the parametric conditions for the existence of the bistable characteristics of the four-bar compliant mechanism with one flexible member are proposed. Then, taking the compliant bistable switch as an example, the internal relations between the driving characteristics of the four-bar compliant mechanism, the initial motion position of the mechanism and the parameters of the flexible member are explored. Finally, based on the improvement of the performance of the compliant bistable switch, the optimization analysis of the maximization of the motion range of the driving link and the maximization of the deformation energy of the flexible member are carried out. The research provides a theoretical basis for the product development and control of a bistable four-bar compliant mechanism.

THE RUNNING CAR WITH THE LETTERED REACTIVE POINT IN THE ZONI BEACH CONTACT THE WHEEL ROOM WITH THE SUPPORT SURFACE

Conclusion. As a result of the studies of the car with upgraded wheel drive: 1. The patent search of directions of modernization of wheel directions in modernization of wheel drives of the car allowed to identify possible directions of modernization of a wheel drive. 2. To modernize the wheel propulsion, it is proposed to include a movable weight acting on the flexible member in the area of contact and exit area. 3. Conducted experiments at the landfill of NATO NATI revealed the advantage of upgraded wheel propellers over the existing traction by 15-20% 4. Based on the results of the experiments graphical dependencies were constructed: - traction balance of the car; - ways of acceleration of the car; - the acceleration time of the car. 5. The model of the car with modernized wheel motors has been developed. Increasing the patency of military vehicles in difficult conditions close to combat ensures the success of the task. Therefore, the study of the modernization of the wheel drives of a military vehicle and their implementation in military units is an important scientific work. Purpose of the study: improving the patency of the military vehicle, the dynamics of its acceleration and wheel drive efficiency Objectives of the scientific work: is to improve the design of the wheel drive of a military vehicle, determine the parameters of traction balance, path and acceleration time. In the scientific work the researches of the military car with the modernized wheel propulsion, which are all leading, when using the car in difficult conditions close to combat, are carried out. Upgraded wheel drives allow the use of variable thrust and torque realization on the drives. During the work the tensometric laboratory was used for traction tests on the basis of MAZ-543 at the landfill of NAT NATI in Odessa. The main devices are a mobile measuring complex and an electronic dynamometer.

Acoustic-Structure Interaction in an Adaptive Helmholtz Resonator by Compliance and Constraint

The acoustic energy attenuation capabilities of traditional Helmholtz resonators are enhanced by various methods, including by coupled resonators, absorbing materials, or replacement of rigid walls with flexible structures. Drawing from these concepts to envision a new platform of adaptive Helmholtz resonator, this research studies an adaptive acoustic resonator with an internal compliant structural member. The interaction between the structure and acoustic domain is controlled by compression constraint. By applying uniaxial compression to the resonator, the flexible member may be buckled, which drastically tailors the acoustic-structure interaction mechanisms in the overall system. A phenomenological analytical model is formulated and experimentally validated to scrutinize these characteristics. It is found that the compression constraint may enhance damping capabilities of the resonator by adapting the acoustic-structure interaction between the resonator and the enclosure. The area ratio of the flexible member to the resonator opening and the ratio of the fundamental natural frequency of the flexible member to that of the enclosure are discovered to have a significant influence on the system behavior. These results reveal new avenues for acoustic resonator concepts exploiting compliant internal structures to tailor acoustic energy attenuation properties.

Becoming the Ars Poetica

This introductory chapter provides a background of Horace's Ars Poetica, a 476-line poem revered for over fifteen hundred years as the indispensable guide for practicing poets. Ars Poetica provided a blueprint for efforts at “updated” rules of literary composition and it inspired numerous famous translators and imitators. Yet this poem has proven hard to love for recent readers. As its ostensible value as “a kind of literary 'Magna Carta'” receded and it ceased to be widely regarded as a document that could ever sincerely aid in literary composition, the Ars Poetica came to develop an entrenched reputation of being tedious and devoid of artistry. This duality is inevitably tied up with the understanding of it as modeled upon earlier Greek works, a relation that both granted the Ars Poetica a greater standing and yet doomed it to be seen as “an anthology of previous ideas, not a system of thought in which each idea has its place as a living and flexible member of an organically unified discourse.” This book then considers the Ars Poetica as a complete and exceptional literary achievement in its own right. It also elucidates the key place of the Ars Poetica in the Horatian corpus.

Fast, Accurate Models for Predicting the Compliance of Elastic Flexure-Jointed Robots

Robot manipulators having elastic links or flexure joints have a number of advantages, especially in simplifying the control of contact with other objects. However, current simplified parametric models of flexure motion do not accurately predict the behavior of these mechanisms under large deflections. This paper presents a “smooth curvature model” of flexure behavior that describes the curvature of a highly flexible member such as a flexure joint using a basis of three orthogonal polynomials. Using this model, we show that it is possible to predict the planar stiffness these mechanisms, even in cases where the deformation of the hinge is too large for the linear Euler-Bernoulli beam bending model. Using both finite element methods and the much less computationally expensive proposed model, numerical results will demonstrate that it is possible to accurately predict the in-plane compliance of a highly flexible mechanism in the presence of an external load. The results of this work are significant because they demonstrate that the behavior of flexure-based robotic mechanisms can be modeled quickly and with few parameters, enabling their use in closed-loop control for situations where collision safety is a concern, and rigorous model-based path planning for obstacle avoidance, among other applications.

Investigation of the Meshing Conditions of a Flat Wheel Harmonic Gear Drive

The function principle of the flat wheel harmonic gear drive is similar to the basic principle of the classical harmonic drives. The flexible and the solid gear of the drive are coaxial flat wheels. The rotating wave generator deforms periodically and elastically different portions of an annular face gear on the flexible member in axial direction into engagement with teeth on an annular face gear on the solid member. The numbers of teeth of the face gears are different. An analytical method is introduced, that investigates meshing conditions of flat-wheel harmonic drives. The numbers of the connected teeth taking part in the load-transmission and the tangential component of the acting force on them in the range of tooth engagement are calculated. It depends on the loading torque, so calculations were launched at different levels of torques in case of various parameters. The tooth flanks were approximated by planes. Results are compared with the results of calculations based on finite element analyses.