Data shows that elderly people are more likely to live alone than younger people, meanwhile the percentage of elderly people with disabilities increases significantly with age. These trends and facts bring a number of issues. One of these we would like to solve is that it is difficult and dangerous for them to lift the heavy loads through ladder. Sometimes it is also very dangerous for normal people, not to mention to people with reduced mobility. In order to solve these issues and reduce the possibility of accident, we have come up with a new ladder used for attics that can transport the heavy loads automatically. As transmission part we use a rack and pinion mechanism to achieve a   smooth transport and a ratchet mechanism for stopper to avoid sudden accident drops.  The ladder also can be hidden when not using it.

Variation analysis, or tolerance analysis as it is sometimes called, is typically used to predict variation in critical dimensions in assemblies by calculating the stack-up of the contributing component variations. It is routinely used in manufacturing and assembly environments with great success. Design engineers are able to account for the small changes in dimensions that naturally occur in manufacturing processes, in equipment, and due to operators and still ensure that the assemblies will meet the design specifications and required assembly performance parameters. Furthermore, geometric variation not only affects critical fits and clearances in static assemblies, it can also cause variation in the motion of mechanisms, and their dynamic performance. The fact that variation and motion analysis are both dependent upon the geometry of the assembly makes this area of study much more challenging. This research began while investigating a particular application of dynamic assemblies - automobiles. Suspension and steering systems are prime examples dynamic assemblies. They are also critical systems, for which small changes in dimension can cause dramatic changes in the vehicle performance and capabilities. The goals of this research were to develop the tools necessary to apply the principles of static variation analysis to the kinematic motions of mechanisms. Through these tools, suspension and steering systems could be analyzed over a range of positions to determine how small changes in dimensions could affect the performance of those systems. There are two distinct applications for this research, steering systems and suspension systems. They are treated separately, as they have distinct requirements. Steering systems are mechanisms, for which position information is most critical to performance. In suspension systems, however, the higher order kinematic terms of velocity and acceleration often are more important than position parameters.

Compression of elastomer elements are nonlinear due to the cross-linked molecular structure owing to a property known as hyperelasticity. Hyperelasticity is defined as the nonlinear stress-strain behavior shown by rubber like materials which can be strained up to a range of 700% in tension and up to 40% in compression. The stress-strain behavior is modeled by using different material models which predict the behavior very precisely.  Linear actuators from Cascade Drives AB uses a patented load sharing mechanism using elastically deformable elements to distribute the torque evenly between all the gears interacting with a common gear rack. An accurate model predicting the response of elastomer under compression has been developed in this thesis project. The elastomers were loaded in compression to provide flexibility for the system. First a static model was developed, where both a rectangular and a cylindrical roller model were analyzed.  The two models were derived using a continuum mechanics approach and the stiffness of the elastomers along with the torque output of the gearbox was calculated. A MATLAB model and an FEA model using ANSYS was created, and the results were compared. An error estimate between the MATLAB and FEA results for the rectangular and roller model was plotted for a certain β° of rotation of the gear. The models were also checked for different materials and the output torque for the different materials was plotted and analyzed. Finally, the experimental results were compared with the MATLAB results for the rectangular and roller models. The rectangle and roller model can be both used to predict the behaviour of using elastomers as the load sharing elements in applications. / Kompression av elastomerelement är olinjär till följd av den tvärbundna molekylära strukturen, en egenskap som kallas hyperelasticitet. Hyperelasticitet definieras som det icke-linjära spännings-töjningsbeteendet som uppvisas av gummiliknande material vilka kan töjas upp till av 700% och upp till komprimeras upp till 40%. Spänningsbelastningsbeteendet modelleras med hjälp av olika materialmodeller som förutsäger beteendet.  Cascade Drives linjäraktuatorer använder elastiskt komprimerbara element i sin lastfördelningsmekanism för att använda multipla plinjonger på ett kuggrack utan att få ett överbestämt system. Lastfördelningsmekanismen ger även en viss flexibilitet för systemet.  En modell som förutsäger responsen hos elastomerer under kompression har utvecklats i denna avhandling. Två geometriska former undersöktes modeller togs fram för både en rektangulär och cylindrisk rulle. De två modellerna härleddes med en kontinuummekanisk metod och elastomerernas styvhet beräknades. En MATLAB-modell och en FEM-modell i ANSYS skapades och resultaten jämfördes och en feluppskattning modellerna gjordes. Modellerna undersöktes också för olika material och utmattningsegenskaperna för de olika materialen analyserades.  Rektangel- eller rullmodellen kan båda användas för att förutsäga hur en elastomer skulle bete sig i en växellådsapplikation.

This thesis describes a project of a mobile stage device that will be used for a concert tour of Lucie. The first part characterizes the given task and expounds description and function of the device itself. The second part focuses on the design concept of supporting frames. This is followed by design and calculation of all mechanisms, actuators and construction of individual moving parts of a sliding and lifting platform. The last part verifies stability of the whole construction in accordance with appropriate standards. The thesis also contains technical documentation, which is to be found in appendix.

This diploma thesis deals with the design of the linear axis of a heavy machine tool. It describes the basic specifications of these machines, their manufacturers, the parts of which the axis consists and the design itself. The design includes several design variants, calculation of the movement mechanism, drive and linear guide. Follows the selection of the most suitable variant and the drawing documentation of the resulting linear axis.

В данной магистерской диссертации представлены результаты разработки методов повышения точности преобразователей вращательного движения в поступательное для систем отсчета перемещения рабочих органов станков с ЧПУ, что и является целью выпускной квалификационной работы. Актуальность темы обусловлена тем, что точность машин и механизмов является основной характеристикой их качества. Традиционные механические передачи (зубчатые, реечные и др.) имеют широкое применение во всех отраслях машиностроения. Требования к точности изготавливаемых деталей существенно ужесточаются, поэтому необходимо непрерывно совершенствовать методы повышения точности передач. Научная новизна обусловлена разработкой новых методов повышения точности систем отсчета перемещений путем уменьшения или ликвидирования кинематических погрешностей и погрешностей от износа преобразователей вращательного движения в поступательное. Рассмотрены элементы, применяемые при построении современных систем отсчета перемещений и возникающие в них погрешности. Проведен анализ существующих методов уменьшения кинематических погрешностей и погрешностей от износа преобразователей вращательного движения в поступательное. На его основе разработаны: метод отсчета перемещений рабочего органа станка с компенсацией погрешностей ходового винта; метод снижения износа передачи винт-гайка скольжения; метод снижения износа передачи винт-гайка качения; метод отсчета перемещений рабочего органа станка с коррекцией кинематических погрешностей рейки; метод снижения износа зубчато-реечной передачи; насос, предназначенный для использования при реализации перечисленных методов. В ходе работы над магистерской диссертацией было подано шесть заявок на изобретения. В результате было получено пять патентов: патент на изобретение №2750575 «Насос шестеренный реверсивный», патент на изобретение №2756797 «Передача винт-гайка качения», патент на изобретение №2764105 «Зубчато-реечный привод подачи металлорежущего станка с ЧПУ», патент на изобретение №2768807 «Устройство отсчета перемещений рабочего органа машины с ходовым винтом» и патент на изобретение №2767381 «Передача винт гайка скольжения». На рассмотрении в ФИПС находится заявка на изобретение №2021114570 «Зубчато-реечный привод подачи рабочего органа тяжелого крупногабаритного металлорежущего станка». / This master's thesis presents the results of the development of methods for precision improvement of reference systems for the movement of movable operating element of CNC machines, which is the purpose of the final qualifying work. The relevance of the topic is due to the fact that the precision of machines and mechanisms is the main characteristic of their quality. Traditional mechanical gears (gear, rack and pinion, etc.) are widely used in all branches of mechanical engineering. The requirements for the precision of manufactured parts are significantly tightened, so it is necessary to continuously improve methods for improving the precision of transmissions. The scientific novelty is due to the development of new methods for improving the precision of displacement reference systems by reducing or eliminating kinematic errors and errors from wear of rotary motion converters to translational. The elements used in the construction of modern displacement reference systems and the errors arising in them are considered. The analysis of existing methods for reducing kinematic errors and errors from wear of rotary motion converters to translational motion is carried out. Based on it, the following methods have been developed: the method of counting the movements of the movement of movable operating element of the machine with compensation of errors of the lead screw; the method of reducing the wear of the transmission screw-nut sliding; the method of reducing the wear of the rolling screw-nut transmission; the method of counting the movements of the movement of movable operating element of the machine with correction of kinematic errors of the rail; the method of reducing the wear of rack and pinion transmission; the pump, designed for use in the implementation of the above-mentioned methods. During the work on the master's thesis, six applications for inventions were submitted. As a result, five patents were obtained: patent for invention No. 2750575 "Reversible gear pump", patent for invention No. 2756797 "Rolling screw-nut transmission", patent for invention No. 2764105 "Rack-and-pinion feeding drive of CNC metal cutting machine", patent for invention No. 2768807 "Device for counting the movements of the operating member of a machine with a drive screw" and patent for invention No. 2767381 "Sliding screw-nut gearing". The application for invention No. 2021114570 "Rack-and-pinion feeding drive of the operating member of a heavy large-sized metal-cutting machine" is under consideration in the federal institute of industrial property.

This diploma thesis is concerned with providing a construction proposal of a linear axis X for multifunctional machining center. Moreover, this work presents characterisations of machining centers, overview of manufacturers, list of main construction components used in the linear axis, their evaluation, assessment of various options for construction, which are then explained further. These detailed construction methods include calculations with the subsequent choice of feed system component. Ultimately, final evaluation of chosen option is provided as well. Another section of this thesis is also an economical assessment and 3D model alongside with mechanical drawing.

This master thesis aims to develop a test methodology for electromechanical linear actuators. A linear actuator acts as a linear motor, converting a power source to linear motion. The electromechanical linear actuator in this project has an electric motor as its power source and uses a rack and pinion system to transfer that power to linear motion.  The test methodology is to impose a force onto the rack of the actuator, to ensure that operation under a load scenario is within specification. To accomplish this, the design of a test rig implementation is analyzed. The test rig consists of the test unit, which is to be tested, the load unit, which is to provide the load force, and a control system for the load unit. The load unit is another linear actuator and is controlled via a load cell. The load cell gives out the load force being applied, and the controller gives out the corresponding appropriate motor command to the load unit to ensure the load force is as desired. This analysis is done through simulation of the setup. Viable options for the setup were first analyzed in order to implement the deemed promising options for a setup into a simulation environment. The simulation environment in this project was Simscape, an extension of MATLAB’s Simulink. In simulation the parameters for the test rig were rigorously analyzed, in order to determine acceptable thresholds. The primary load unit tested was another electromechanical linear actuator from Cascade Drives, the model A-100-8P. Two secondary setups, one using the same model as being tested, and another setup using two of the models being tested. Simulation found that the suggested options’ applied load force have a poor rise time, large overshoot and substantial oscillation errors. The primary source for this was determined to be the latency between load cell input, and motor command output in the controller. The poor metrics from the result could lead to problems when emergency braking, and with a long honing period, which would render most test data unusable.