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Training with use of mechatronic devices is an innovative rehabilitation method for patients with various locomotor dysfunction. High efficiency of training is noted in systems that combine a treadmill or orthosis with a body weight support system. Speed control is a limitation of such rehabilitation systems. In commercially available devices, the treadmill speed is constant or set by the therapist. Even better training results should be obtained for devices in which the speed of the treadmill will be automatically adjusted to the patient walking pace. This study presents a mechatronic device for locomotor training that uses an algorithm to adjust the speed of the treadmill. This speed is controlled with use of a sensor that measures the rope inclination. The end of rope is fastened to the orthopaedic harness. Speed control is realized in such a way that ensures the smallest possible swing angle of the rope. A fuzzy controller was applied to adjust the treadmill speed. The drive system of the treadmill is equipped in a servodrive with PMSM motor and energy recovery module, which allows smooth speed control, limiting acceleration and minimizing electricity consumption. The presented solution was implemented in a real object and subjected to experimental tests. more...

The modern industrial and consumer applications in accordance with the concepts of Industry 4.0 and the Internet of Things are characterized by autonomy and self-sufficiency. This has led to an increase in the interest for the so-called smart materials, capable of combining the functionalities of sensors, actuators and, in some applications, control systems. An important group of smart materials are shape-memory alloys, among which nickel–titanium (NiTi) alloys are the most known. In this article, the influence of phase transformation on the mechanical properties of thin NiTi alloy wires was investigated. During the test, the influence of the heating currents on the displacement and the force generated by the thin NiTi wires were analyzed. The temperature of the wires during heating was measured by a thermographic camera. This study proved the maximum value of the wires’ displacement was related to the value of the heating current. During the research, the dependence of the transformation dynamics on the value of the heating currents was also proved. In addition, the influence of the surface inhomogeneity of the thin NiTi alloy wires on the accuracy of the thermographic measurements was analyzed. For the experimental research described in this article, we used the NiTi alloy whose trade name is Flexinol, produced by DYNALLOY (Inc. 2801 McGaw Ave. Irvine, CA, USA). more...

Background. Forefoot adduction is a relatively common problem. It is usually mild or it can be effectively managed conservatively. Severe deformities may require surgical treatment. The aim of the study was to perform a clinical and radiologic evaluation of forefoot adduction correction using medial cuboid and cuneiform osteotomy with a transposed wedge. Material and methods. This is a retrospective study involving 16 patients who underwent 20 procedures. Mean age at surgery was 6 years (3-13). Clinical evaluation was based on measurements of forefoot deviation and patients’/care-givers’ subjective opinion. The radiologic parameters assessed comprised the first ray angle, talar-first metatarsal angle, calcaneal-fifth metatarsal angle, talocalcaneal angle, metatarsus adductus angle, and Kilmartin’s angle. Results were then compared in children below and above 6 years of age. The mean duration of follow-up was 4.6 years (2-9). Results. The clinical and subjective outcome was rated as good in 16 procedures and satisfactory in 4. The talar-first metatarsal angle, calcaneal-fifth metatarsal angle, metatarsus adductus angle, and Kilmartin’s angle were significantly reduced, while the talocalcaneal and first ray angle remained unchanged. A significantly better correction of metatarsus adductus and talar-first metatarsal angle was achieved In children below 6 years of age compared to older patients. Conclusions. 1. Medial cuneiform and cuboid osteotomy with a transposed wedge improves both clinical and radiological parameters, especially in children under the age of 6. 2. Besides the metatarsus adductus angle, the talar-first meta­tarsal, calcaneal-fifth metatarsal and Kilmartin’s angles appear to be good radiologic indicators of correction. more...

Nowadays, conveyor belts with synthetic fabric made of multilayered composite materials are used in many industries. The dimensions of these devices are usually large, which makes maintenance work more difficult. Install or dismantle of conveyor belts in these devices is carried out sporadically. Because of that belt assembly devices are often overlooked during the construction process of the conveyor. This means that conveyor belts are often lifted through various types of chains or steel profiles. Due to the length of the belts, their weight is often very high. This may result in conveyor belts being damaged during install or dismantle. The paper focused on analyzing the stress distribution in composite conveyor belt depending on the way how it is lifted. Numerical analysis was performed in commercially available software based on finite element method. Two cases of lifting a belt with a weight of 2.5 tons have been compared. Based on the obtained results, recommendations were made on how to install or dismantle conveyor belts in large-sized conveyor. more...

One of the most popular meshless methods in engineering applications is SPH method, broadly used in the simulation of cutting process and fluid-structure interaction. Examples of this method usage, by a module implemented in the commercial software LS Dyna, are presented by authors. They are compared with experimental tests. In this publication are presented experimental and numerical results from observing the behaviour of the bodies during impact with water. The need to study this phenomenon resulted during the design process of an angler fishing float, which was developed and applied for patent protection by one of the co-authors. For this purpose, a station composed of a transparent water-filled tank attached to a force sensor was created and the numerical model was prepared. Bodies in the form of a SPHere, cube, cylinder, and cone of a constant volume of one litre each were immersed in water at a constant displacement of 100 mm, represented by a quadrant of sinus function at frequencies of 0.5 Hz, 1 Hz, 2 Hz and 3 Hz. The test was performed on a dynamic endurance machine manufactured by MTS 858 Table Top System. Parellely was developed the numerical model with water as SPH elements. Numerical analysis was performed on the mpp (massively parallel processor) version of LS Dyna R11 with the use of 3 nodes and 10 processors per node. Principles of the SPH method implemented in LS Dyna are described in the literature. The purpose of this article was to determine the influence of the body shape immersed in water on the value of the load recorded on the force transducer at the base of the tank. Additionally, estimation of the influence of frequency on loads was to notice. The paper presents the results of experimental studies, which were then compared with the results of numerical simulation. more...

This article presents preliminary research in designing overlays and insoles for footwear with measurement components located in the mid-foot and the heel area. With this type of measurement components, the gait can be analysed in any place of the room that was designated for this examination. With measurement components used in separate components, the gait can be measured in its different phases. With additive manufacturing technology, the device designed can be quickly verified. more...

Background. The goal of this study was to perform a functional (subjective) and radiological evaluation of patients who had undergone forearm lengthening by distraction osteogenesis years before. Material and methods. Eleven patients with forearm shortening of various etiology were enrolled. They had undergone a total of 21 lengthening procedures. A retrospective analysis of radiological data was conducted and a subjective evaluation was accomplished by using a modified QuickDASH-9 questionnaire. Results. Average bone lengthening was 3.54cm, and mean lengthening index was 40.53day/cm. Eight pa­tients answered the questionnaire at a mean of 7.8yrs after the treatment. The mean questionnaire score was 9.75pts (of 36). Four patients rated the overall function of the affected limb as improved following distraction, while 3 patients were not able to see any improvement. One patient reported that the lengthening had impaired limb function. With regard to cosmetic aspects, 4 patients reported a worsening after the lengthening procedure while 3 patients reported improvement and 1 patient did not note any changes. Conclusions. 1. Despite deformities and functional limitations, patients after forearm lengthening only occasionally suffered from moderate intensity pain. 2. The radiological outcomes were positive and the rate of complications was low. 3. The radiological outcomes did not match patient-declared functional and cosmetic results. more...

Context: Spine duplication is a rare condition, with various extents and severe additional anomalies. The goal of this study was to describe a unique case of a boy with split notochord syndrome who was followed up from birth until maturity. Findings: Physical examination at birth showed defects of the abdominal wall and cloacal exstrophy with visible urether outlets. A transposed anus was present in the perineal region. Split bony elements of the spine with nonpalpable sacral bone were noted. A soft, skin-covered lump, with the consistency of a lipoma, was present in the sacral area. There was asymmetry of the lower limbs: the left was hypoplastic, with a deformed foot and hip. Computed tomography revealed a normal shape of the Th12 and L1 vertebrae, whereas the L2 was split. Downward from L3, there were two vertebrae at each level, with two spinal canals. The spinal cord divided into two “semicords” at the level of L1. Neurologic status and the shape of the spine remained unchanged during puberty. The last follow-up was performed at the age of 18 years. He managed to walk independently in prosthesis with visible limping. Conclusion: Spine deformities are always suspected in neonates with lipoma in the sacral region, which may sometimes be serious. Walking ability and quality of life depend on neurologic deficits; even with long duplication and double sacrum, walking can be a feasible option. more...

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. more...

This paper discusses the stability of systems controlling patient body weight support systems which are used in gait re-education. These devices belong to the class of underactuated mechanical systems. This is due to the application of elastic shock-absorbing connections between the active part of the system and the passive part which impacts the patient. The model takes into account properties of the system, such as inertia, attenuation and susceptibility to the elements. Stability is an essential property of the system due to human–device interaction. In order to demonstrate stability, Lyapunov’s theory of stability, which is based on the model of system dynamics, was applied. The stability of the control system based on a model that requires knowledge of the structure and parameters of the equations of motion was demonstrated. Due to inaccuracies in the modeling of the rope (one of the basic elements of the device), an adaptive control system was introduced and its stability was also proved. The authors conducted simulation and experimental tests that illustrate the functionality of the analyzed control systems. more...

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. more...

The main aims presented in the work constitute conceptual solutions of treadmill control systems with foot pressure sensors feedback. The article also contains results of further experimental studies regarding the device. more...

The aim of this paper is to analyse the structure of a transformer subjected to the seismic impact, determine the state of critical stresses on the structure, but also to ensure that the structure remains undestroyed after the impact of seismic forces. The numerical calculations, in particular those related to the structure load states, were based on the standard: IEEE Std 693-2005, IEEE Recommended Practice for Seismic Design of Substations. more...

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. more...

The article presents one of the concepts of the performance of keeping up the movement of a gantry behind the load. For reaching this solution, a PID controller has been applied. The worked out control algorithm has been implemented and tested employing a 3D Crane 3D. The results of experimental research have been compared with the findings of numerical simulations. more...

The purpose of this paper is to present a novel mechatronic system for gait re-education which consists of a body weight support system (BWS system) and a treadmill. This publication covers mainly issues related to the design and optimization process of a control algorithm dedicated for the unloading system. The proposed control system is based on a fuzzy logic controller coupled with a PID regulator. The optimization of parameters for regulators has been conducted based on numerical simulations in which a hybrid optimization method combining a genetic algorithm with a gradient algorithm has been used. The developed control system has been tested experimentally. more...

Authors report a case of a patient with varus deformity of right knee, caused by wide resection of proximal metaphysis and epiphysis of right tibia. Afore mentioned procedure led to loss of right knee joint integrity, with its lateral instability, shortening, and axis deviation of right tibia. Surgical treatment of this complications was performed in several stages and took about 5 years, starting from temporal, lateral hemiepiphysiodesis of proximal tibial epiphysis, subacute epiphysiolysis of proximal tibial epiphysis and high valgus tibia osteotomy, at the end finished with medial tibia condyle reconstruction with autogenic graft and osteoconductive substances. The proper mechanical and anatomical axis of the right limb, with full stability and movement of right knee was achieved after those surgeries. The process of treatment of lower extremity axis deviation takes long time, frequently involves several surgeries and needs firm cooperation between doctor and patient. more...

The paper addresses analytical, numerical and experimental aspects of the design of controlled fluid damper. The mathematical model served the development of a numerical model in MATLAB/Simulink environment. The selected important aspects of the tracked vehicles dynamic modelling process related to dynamics of the drive system and the suspension of selected tracked vehicles are presented. The main aim of the article was to present the investigation results of the experimental studies of a prototype rotary shock absorber at various magnitudes of control current was presented in this paper. Simulation and preliminary experimental results comprising resistance force values as a function of angular displacement and angular velocity are presented. more...