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The use of optimization procedures in tuning vibration dampers

This paper presents an algorithm for minimizing the resonance amplitudes of vibrating systems with dynamic vibration dampers. Damper parameters are optimised using an objective function which describes the maximum of the resonance curve for the first resonance. The algorithm described here is based on a spectral transfer function and can be applied to multi-degree-of-freedom systems. The research makes use of models of discrete as well as discrete-continuous systems. A method for formulating minimization problems is proposed which allows global optimization using gradient procedures. Sequential linear and quadratic programming methods are used. Examples of different mechanical systems with vibration dampers are also presented.

Rotary Shock-Absorber with Magnetorheological Valves

The paper analyses the problem of design of the magnetorheological (MR) fluid valve to be constrained within the cylindrical hole in the stationary barrier of rotary shock-absorber. The main objective is to maximise valve’s dynamic range (i.e. controllable/passive ratio of shock-absorber’s resistance torque) thus to maximise controlled part of the pressure drop along the MR valve. To obtain this, a special type of two-winding configuration with annular fluid gap is proposed.

Minimisation of the explosion shock wave load onto the occupants inside the vehicle during trinitrotoluene charge blast

The aim of this study was to elaborate identification method of crew overload as a result of trinitrotoluene charge explosion under the military wheeled vehicle. During the study, an experimental military ground research was carried out. The aim of this research was to verify the mine blast resistance of the prototype wheeled vehicle according to STANG 4569 as well as the anti-explosive seat. Within the work, the original methodology was elaborated along with a prototype research statement. This article presents some results of the experimental research, thanks to which there is a possibility to estimate the crews lives being endangered in an explosion through the measurement of acceleration as well as the pressure on the chest, head and internal organs. On the basis of our acceleration results, both effectiveness and infallibility of crew protective elements along with a blast mitigation seat were verified.

Shaping the Dynamic Characteristics of Military Special Vehicles

The article presents a motion dynamics model of a sample military special vehicle, two suspension control algorithms and the results of three different numerical experiments that have been conducted. The applied measure of appraisal was the comparison of the amplitudes of displacement, speed and acceleration – both linear (in the vertical direction) and angular (in the longitudinal and transverse planes) in time.

Mechatronic Device for Locomotor Training

Abstract This paper presents a novel mechatronic device to support a gait reeducation process. The conceptual works were done by the interdisciplinary design team. This collaboration allowed to perform a device that would connect the current findings in the fields of biomechanics and mechatronics. In the first part of the article shown a construction of the device which is based on the structure of an overhead travelling crane. The rest of the article contains the issues related to machine control system. In the prototype, the control of drive system is conducted by means of two RT-DAC4/PCI real time cards connected with a signal conditioning interface. Authors present the developed control algorithms and optimization process of the controller settings values. The summary contains a comparison of some numerical simulation results and experimental data from the sensors mounted on the device. The measurement data were obtained during the gait of a healthy person.

Mechatronic treadmill for gait reeducation with control algorithm of treadmill speed adaptation

Different types of devices, from the simplest (medical walkers) to the most technologically advanced ones (mechatronic devices), are widely used to support the rehabilitation process for people who suffered strokes or have other disabilities—especially to enhance their mobility. This article presents a new mechatronic system for gait reeducation, which consists of two main components: training treadmill and body weight support system. The device is also equipped with sensors for measuring the rope inclination angle, rope tension and foot pressure on the ground. The transmission of measurement and control signals between the computer with control system and the electromechanical part of the device is realized by means of three real-time boards. This publication covers certain issues related to the device design process, integration of the main components, as well as the description of the developed treadmill speed adaptation algorithm and experimental verification of such control system. The speed of treadmill belt is adjusted by a feedback loop with a rope inclination angle measurement. Because of the kind of the connection of the treadmill (the control signals are sent to the buttons in the treadmill control panel) and related limitations, a proper conversion of the control signal was required, from a continuous one to a digital square wave signal with variable period. Developing an optimal treadmill speed control algorithm in this case was an interesting engineering challenge.

Estimation of kinematic parameters in a model of artificial aortic valve leaflets

Currently, one of the least invasive methods of replacing a dysfunctional aortic valve in humans is Transcatheter Aortic Valve Implantation (TAVI). The shapes of expandable stents have an influence on the geometry of the leaflets and differ from those mounted by open heart valve surgery. There are different types of balloon and selfexpandable TAVI valves. For the purposes of analysis of the influence of constraints on the kinematic parameters of aortic valve leaflets, prototype leaflets were made of polyurethanes. Results from the numerical model and a machine for testing the durability of the heart valve are presented.

State-of-the-art of transcatheter treatment of aortic valve stenosis and the overview of the inflow project aiming at developing the first Polish TAVI system

Initial experience of transcatheter aortic valve implantation (TAVI) or replacement (TAVR) has ap-peared as a promising minimally invasive technology for patients disqualified from surgical treatment (SAVR). Safety and efficacy of TAVI has been analyzed and assessed through numerous registries and trials. Furthermore, results obtained from comparative TAVI vs. SAVR trials proved that both treat¬ments can be considered equal in terms of post-procedural mortality and morbidity in high-risk, as well as lower risk patients. However, there are still some issues that have to be addressed, such as higher chance of paravalvular leakage, vascular injuries, conduction disturbances, malpositioning and the yet unmet problem of insufficient biological valves durability. Recent technological developments along with the learning curve of operators prove a great potential for improvement of TAVI and a chance of surpassing SAVR in various groups of patients in the near future. In pursuit of finding new solutions, the CardValve Consortium consisting of leading scientific and research institutions in Poland has been created. Under the name of InFlow and financial support from the National Center for Research and Development, they have started a project with the aim to design, create and implement into clinical practice the first, Polish, low-profile TAVI valve system, utilizing not only biological but also artificial, polymeric-based prosthesis. This review focuses on current developments in TAVI technologies including the InFlow project.

Hybrid Simulation of Tracked Vehicle Suspension on Real-Time Environment

The work presents simulation method of dynamic properties used as assistance in the construction process of suspension systems for high-speed tracked vehicles. Special consideration has been given to the real-time coupling of virtual models with the dynamic response of actual elastic-damping elements of the vehicles. An original design method has been proposed. The method is characterized by the fact that each of the design stages are not performed sequentially, but are parallel to each other and that at each level, mutual coupling between the tasks of the design process occurs. The proposed simulation method using the dSpace system is based on the integration of virtual environment such as LMS Virtual Lab or MATLAB/Simulink with the actual object such as a damper, by means of dedicated input/output devices operating in real time. The method developed in the work allowed for an extension of the classic co-simulations, that is, simulations in two coupled virtual environments, to include an actual component or, rather – its dynamic – often non-linear – characteristic, its response to excitation. The method developed in the work allowed for an extension of the classic co-simulations, that is, simulations in two coupled virtual environments, to include an actual component or, rather – its dynamic – often non-linear – characteristic, its response to excitation.The developed test method and the computer programs have been verified by means of experimental measurements of the dynamic characteristics of the actual object during test-ground tests and in the laboratory. The obtained results of the simulations and experiments allow to confirm the validity of the assumed thesis, which has been included in the summary.

Preliminary tests of new composite material based on shape memory alloys for artificial aortic valve leaflets

Nowadays bioengineers actively search for new materials for different kind of implants. The natural tissues used for these purposes have many defects, of which the most important is the possibility of transplant rejection. However, properties of artificial biomaterials have also many deficiencies among which there are insufficient mechanical and fatigue properties. The example of this can be the aortic valve leaflets, which anatomy is complicated both in terms of geometrical shape and internal structure. This causes significant difficulties with finding suitable material for this type of implants. The most frequently used methods of obtaining material for that purpose are based on the processing of biopolymers (e.g. electrospinning) and also on extraction of porcine pericardial tissue. This paper presents a new concept of composite biomaterial based on shape memory alloys (SMA) with biopolymer matrix. The SMA thin fibers imitate collagen fibers in aortic valve leaflets which stabilize the aortic valve motion and reduce stresses. The numerical simulation of blood flow was done to verify assumptions and investigate the extent of deformation of the new composite structure.