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Performance increasing of robot-aided training in stroke elbow rehabilitation is the goal of this paper. Therapist holds on the arm of patient and guides the center of mass along a desired trajectory. In robotic rehabilitation, when the arm of patient rotate within the desired boundaries, (s)he should ideally not feel the robot. The robot needs to actively compensate for the weight of the exoskeleton and reflected mass of the motors. A nonlinear torsion spring can be used and also a counter-torque as a function of arm angle is applied by the motor. Applying the springs affords more convenience, it allows smaller motors to be used, the size of required brakes can be reduced and inherent safety is introduced in rehabilitation robots. Furthermore, the robust controller design can be used to compensator the modeling errors and gravitational force. A novel elbow rehabilitation robot is designed based on the cable actuation. The strategy is not just anti-gravitational forces because there should be joint-stiffness control. The uncertainty in the patients arm dynamic is effectively approximated. The motion of closed-loop control system in the presence of parametric uncertainties is investigated. The sliding mode controller with proportional-derivative controller is compared through computer simulation and improvement is observed.

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The scope of this study is to investigation of the rehabilitation of concrete beam column joints retrofitted by use of carbon-fibre-reinforced plastics (CFRPs) to achieve a safe, economic and practicable level of seismic damage. This paper investigates analytically the efficiency of the strengthening technique at improving the seismic behaviour of damaged structures. 4 beam-column connections are tested under reversed cyclic load. The connections have none-seismic detailing of rebars, i.e. no transverse rebar and seismic stirrups are used in the joint core and beam and column critical end zones, respectively. The joints are damaged in different levels and then retrofitted by carbon fibre reinforced materials (CFRP sheets). The strengthened joints were tested again to reach the ultimate drift capacity. The experimental results show that the beam column joints could be retrofitted by external bonding of FRP sheets until a limited level. This level determined for tested joint approximately equal to 1.5% story drift. The specimens initially damaged until 1% and 1.5% drifts showed the capacity increase up tp 5% and 3%, respectively. If the damage level is higher than this repair-ability level, other rehabilitation methods may be useful. Then, to simulate the behaviour of joints, a numerical model was developed in the OpenSees framework version 2.4.0. The tested joints such as reference joint and retrofitted joints are analyzed by Opensees nonlinear software. The open source Opensees software has several models for concrete and reinforcement rebar materials possible for considering reloading / unloading stiffness deterioration and hysteretic energy dissipation during reversed cyclic loads. Also nonlinear beam-column elements with spread or concentrated plasticity make this nonlinear software capable for high accurate simulation. The analytical models are used to assess the efficiency of the CFRP rehabilitation to set an optimum level of damage that the seismic behavior parameters could be compensated, safely, economically and practicable. The results of joint analysis are compared with experimental behavior of specimens. The hysteresis curves of the modeled beam column joints had a high level of accuracy in terms of stiffness degradation, moment carrying capacity, capacity degradation and energy dissipation. So, the model is calibrated for each level of damage intensities. The results showed that the model had a good accuracy in terms of load carrying capacity, secant stiffness, energy dissipation and joint ductility and the error was less than 10% between analytical and experimental results. Then, the effct of some variables such as column axial load and existence of transverse slab connected to the beam was analytically investigated. The results showed that increasing the axial load on the column increased the load carrying capacity and stiffness from 5% to 12% (related to initial damage intensity of the joint), but it had negligible effect on dissipated energy. Also modeling of transeverse slab revealed an increasing effect on the capacity, stiffness and energy. The positive effect was higher in absence of gravity loads on the slab. So, existence of transeverse slab with gravity load had negative effect on secant stiffness in specimens with initial damage higher than 1.5% story drift.

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In this study, the control problem of a knee rehabilitation robot is examined. The main drawback of rehabilitation facilities, such as continuous passive motion, is the lack of feedback from the interaction force between the robot and patient leg. This means that if during the exercises, an unvoluntary motion by patient is generated, the increased interaction force can then damage the patient leg. The interaction force is increased because the robot tries to hold the patient leg along the prescribed reference path. In the current paper, to realize the compliant behavior of the robot, the concept of admittance along with two control methods including adaptive model reference and integral backstepping will be utilized. Adopting admittance control method, the robot will deviate the prescribed path so that the interaction force can be decreased. The obtained simulation results reveal the good performance of the robot even in the presence of noisy sensory data. Additionally, it has been shown that the proposed combined admittance and backstepping controller has better performance, in terms of tracking error and decrease of interaction force, as compared with the model adaptive reference model.

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Reduction of social and financial losses and rehabilitation in important buildings as a result of terrorist attacks and accidental blast is vital. In this regards, using concrete slabs as a protective shield is one of the main methods of protection. Currently, many methods have been used for improve the behavior of this element such as FRP sheets, fibers, high strength concrete and composite concretes. Using these methods is not favorable due to several reasons such as: increase the dead load of structure, increase the cost of project, employ high-tech methodology and needed high skilled worker for implementation. Therefore, for ordinary projects and households, these methods may not cost effective and a simple and more cost effective method needed to be implemented. In this paper, the behavior of RC slabs reinforced with steel wire mesh which is easy to implement and cheap was studied analytically under blast loads. To this goal, effect of different parameters such as number of wire meshes, slab thickness and concrete strength on maximum slab displacement, damage areas and performance of slabs were studied numerically. First the model was built in general FEM software and calibrated to existing experimental and analytical studies. Then numerous slabs with different thickness (40, 60 and 80 mm), concrete strength (30, 40 and 50 MP), different layers of wire mesh (0, 1, 2, 3) where considered and analyzed with a general FEM software. The results have shown that increasing of slab thickness, concrete strength and adding different layers of wire mesh reduces the slab displacement and the damage area. Due to higher damage in thin slabs (4 Cm) and low concrete strength (30 MP), the effect of adding wire were higher. Generally, the slab thickness is the most important parameter in controlling the damage in the salbs under blast load, but increasing the concerete strength and adding different layer of wire mesh, reduced this damages. From the viewpoint of slab performance, which is defined by the amount of displacement and plastic rotation of hinges, it is observed that the performance of thicker slabs (60 and 80 mm) were in the life safety or immediate occupancy state which is quite good for ordinary purposes. Using wire improved the performance of these slabs. In the thinner slab (40 mm) the performance of slab with concerete strength of 30 MP, was not satisfy the life-safety requirement, therefore it is needed to improve this performance. The result of analysis were shown that adding different layer of wire mesh improve the performance of the slab and limits that. Although different layer of wire mesh did not have significant effect on improvement of the slab performance, it limits the performance of slabs to the code’s value in several occations. Generally, it can be concluded that adding the wire mesh could reduce the amount of damage to the slabs under blast loads, which was expected results, but this reduction, is not that much significant for many occations. This method is more effective in thin slabs with lower concerete strnght.

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The extent of masonry structures and their weaknesses against earthquakes will increase the need for research on new ways of seismic rehabilitation of these structures. Recently, in addition to conventional techniques such as Mesh, Shotcrete, and FRP, new materials such as ECC materials have been considered by the researchers to retrofit the masonry walls. The composite materials of cement base, which is one of the types of cement base materials, due to the presence of fibers in the matrix, has a significantly different tensile strain capacity than that of conventional concrete, so that the range of this parameter for a typical mortar is 0.015%, and for composite materials of ECC is from 0.5 up to 6%. In the present study, the effect of these materials on the performance of the bearing masonry walls with in-plane failure modes including the diagonal tension mode (brittle mode) and the bed-joint sliding mode (the ductile mode) were investigated. The results of the research are based on the numerical method. ABAQUS software was used for numerical modeling. Due to validate the model, the available laboratory information of as-built masonry walls has been used. The as-built masonry walls are half scale. The wall dimensions for diagonal tension mode and bed-joint sliding mode were 1900x1400x110 and 2700x1400x160 mm, respectively. The gravity load of the wall was 0.1 MP. The walls strengthened with 20 mm ECC layers on one and both sides. In one case, ECC layers were joint to the foundation and in other case were not. A change in failure mode of strengthened walls (brittle to ductile) and hardening behavior were the main achievement of this research. If the connection between ECC layers and the foundation is absent, the failure mode of strengthened walls will be toe-crushing and rocking mode. If the connection between ECC layers and the foundation is present, the failure mode of strengthened walls will be toe-crushing and bed-joint sliding mode. Other obtained results showed an effective increase in strength and dissipated energy. The extent of this increase depends on how ECC layer is connected to the foundation. If there is no connection between ECC layers and the foundation, the strength and dissipated energy of walls with diagonal tension failure mode for one-side and both-sides ECC layers will be 2.3 and 3 times, respectively, in comparison with those of as-built masonry walls. Whereas for the bed-joint sliding mode, the extent of wall strength and dissipated energy is 1.4 and 1.8. according to the obtained results and comparing the properties of the wall strengthened by one-side and both- sides ECC layers, a significant difference was not observed, especially in bed-joint sliding mode. Appositively, if there is a connection between ECC layers and the foundation, the strength of walls for one-side and both-sides ECC layers will be 3.5 and 6 times, respectively, in comparison with those of as-built masonry walls. Whereas the dissipated energy of walls will be 3 and 4.5 times. Based on these results, if the ECC layers and the wall foundation are connected, the capacity of strengthened walls will be optimized.

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Rehabilitation is a process in which the patient achieves his/her lost ability and individual independence in performing their daily activities using numerous facilities and equipment. About 30% of human life-threatening injuries are related to their hand. The human hand, as one of the most important organs of the human body in interacting with the environment, has the greatest role in maintaining individual independence in daily work. In this article, a rehabilitation system has been designed for hand tendon injury using observations of traditional rehabilitation of hand injuries after surgery and recovery period, and through a mechanism based on structures restricting undesirable degrees of freedom. The mechanism used in this design has been selected by considering conventional tendon injury rehabilitation exercises. In this way, the system can easily bend the finger over the marked joint by using a tendon shape mechanism, which applies force on the tip of the finger. The process of system designing is completed using a prototype to examine the method of operation as well as to obtain the required forces for choosing electrical elements.

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In this paper, an intelligent powerful control scheme is presented for a lower-limb rehabilitation robot. The focus of this study is on maintaining patient safety, focusing on the concept of assist as needed to improve the efficacy of robotic rehabilitation exercises and intelligent controller behavior. The proposed control scheme is consists of force field control and fuzzy logic control. Gravity compensation, friction forces, and interaction torque have been considered to the dynamic model of the system. The force field control method creates a virtual wall along the desired trajectory in the sagittal plane that can guide the patient's gait. Force field control parameters are selected using the fuzzy logic control rules o improve the concept of assist as needed for the rehabilitation robot in order to make a freedom of action for the patient. Therefore, the fuzzy logic control algorithm was proposed to improve the behavioral quality of the rehabilitation robot depending on the patient's ability in the gait process. In this regard, the proposed control scheme has been implemented for the lower-limb rehabilitation robot system. Simulation results show the efficiency of the proposed controller to improve the quality of motorized gait training. 

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Motor units’ malfunction, which happens due to stroke, often affects patients’ hand motion and subsequently restricts their daily activities and social participation. All these factors reduce the patient’s life quality. Therefore, finding a solution to overcome these limitations and improving hand function seems to be valuable. So far, many efforts have been done to design and develop different types of rehabilitation systems. Among all these systems, soft systems have attracted great attention due to their light weight, flexibility, safe interaction and affordability. The goal of this study is to fabricate a soft rehabilitation glove for hand function retrieval so that patients can perform rehabilitation exercises individually. The rehabilitation system presented here includes two different control modes including on/off and proportional modes. Each of them is selected based on patients’ needs. For verification purposes, trajectories of the finger tips were obtained in two modes: “using the glove” and “without using the glove”. Results showed that trajectories of the finger tips in the "using the glove" mode follow a proper path for the user’s digits.
 

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Human ankle-foot gait is the result of a complex interaction between nerves and muscles. A significant number of prosthetic ankle-foots (passive, semi-active, active) have been designed to restore an identical function of a real limb. Excluding passive and semi-active prosthesis who couldn’t generate any positive work, one of the biggest challenges in creating these prostheses is providing the needed power and energy during movement. Supplying this power and energy, requires a high-torque and high-power actuator having high weight, thereby causing a dramatic increase in the weight and size of that prostheses. In this paper, a combination of an active actuator (an electrical motor) and an passive stimulus (a spring) is utilized, which decrease the needed power and energy, and in addition to walking mode can also support running mode up to 2.5m/s. Accordingly, The first stage of this article includes mechanical modeling of the ankle and evaluation of efficiency and power consumption in all presented models. Then the structure of Series Elastic Actuator differed with the previous structures is selected as the best combination.  In this opted structure, power and energy consumption is dramatically declined up to 58% and 26% in walking mode and 64% and 57% in running mode. Consequently, a lighter motor and battery can supply the required power, so the prosthesis chr('39')s weight is subtracted.

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In the present study, the feasibility of ensuring uniform deformations in the lateral bearing system of thin steel shear walls has been investigated. For this purpose, using ABAQUSTM finite element software, a 3-story concrete frame was modeled and analyzed by the nonlinear time history analysis method. Due to the lower weight, speed of execution and consequently the reduction of construction costs in steel shear walls compared to reinforced concrete shear walls, they have been significantly developed. In important buildings in North America and Japan, this type of lateral bearing system has shown very good behavior against strongly earthquakes. Also, due to the good performance of steel shear wall systems, the use of steel shear wall in seismic countries during earthquakes in North Ridge, USA, Kobe and Japan has greatly increased. The system of steel shear walls is similar in performance to plate girder. In steel shear walls, the columns act like flanges, the filler steel plate acts as the web and beam similar to the stiffeners in the plate girder system. In general, the performance of steel shear walls is based on the creation of a diagonal tensile field in the steel plate that occurs after buckling. In 2003, the Canadian Steel Structures FEMA 450 proposed guidelines for the design of steel shear walls. In 2005, the design requirements for steel shear walls with special details were added to the steel structures section of the AISC Regulation. According to ASSHTO 2018 regulations, steel plates are divided into three behavioral ranges slender, moderate, and stocky according to their thickness. In 2021, during research, a new method for evaluating the behavior of steel shear walls with the relationship of part of the plate height to the vertical boundary elements was reviewed. In this type of connection, the middle of the filler plate was not connected to the vertical boundary elements. In this type of connection, reducing the connection length between the filler plate and the vertical elements leads to a reduction in stiffness and bending on the vertical boundary elements. In this paper, three different thicknesses were selected in the behavioral range of slender plates and how to connect them to the surrounding elements was defined in whole and in partial. In this evaluation, the effect of changing the connection length of the steel plate for the range of slender plates is investigated. The connection of steel shear walls to the surrounding members (beams and columns) is based on the percentage of the shear plate and the connection length ratio of steel plates are examined on the maximum relative in-plane displacement (drift) and the displacement of all stories. Uniform distribution of live and dead loads for the roof floor 1 and 5.3 (KNm2) respectively and for the other floors equal to 2.5 and 5.5 (KNm2) respectively is assumed. The behavior of the frame in the first stage is evaluated by the record of the Kobe earthquake. The results showed that in general, reducing the length of the plate connection leads to an increase in the maximum relative in-plane displacement (drift) of the stories and it is possible to control the ductility of the structure. 0. 6  is the critical area for a sender plate 5 mm. Because due to the early buckling and the occurrence of resistance after buckling, the maximum relative in-plane displacement (drift) has decreased. Also, 0.6 and CLR≥0 / 75 introduced as critical areas for 2 mm and 8 mm plates, respectively. In slender plates with very small thicknesses, the shear strength is very low and can be ignored, and the plate enters the post-buckling resistance immediately after loading. For this reason, the results of these plates determine the behavior of the structure. By reducing the thickness, the non-uniformity in the maximum relative in-plane displacement (drift) of the stories was seen, which was significantly improved by using suitable partial connections of the shear steel plate to the surrounding elements.

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The advantages of structures equipped with bracing systems such as high lateral stiffness, light weight of the skeleton compared to flexural frames plus the weakness of flexural frame connections as well as high risk of the performance of these connections during earthquakes always place the bracing lateral stiffness system at equal level of the other seismic-resistant systems in the minds of designers. However, Experiences gained from the concentric brace frames performance during earthquakes showed the undesirable function and hysteresis loops of the bracing system. The early buckling of the brace members causes joint failure, instability and unpredictable seismic behavior of the frame. Researchers tried to avoid the buckling phenomenon by making some changes in brace members structure. Using energy dissipation systems like buckling restrained braces, viscose dampers, friction dampers and yielding dampers were the methods which have been investigated during years. yielding dampers due to their benefits like economic aspects, easy construction, available material, flexible design, durability and significant impact on the seismic responses were one of the devices which has been considered. Many researchers worked on different types of yielding dampers. they used parallel plates yielding dampers on top of the chevron braces and slit dampers along diagonal brace. despite of many researches has been done, but it seems more efficient projects can be achieved in this field. the yielding dampers constructed so far have several considerable problems: i) the existence of one or two-level behavior against earthquakes, ii) the implementation of the welding process in energy-absorbing parts causing premature rupture of steel, and iii) the lack of support system in the event of severe earthquakes or unusual loads outside the design leading to frame instability. This research tries to design a two-level yielding damper with parallel fuse plates using finite element sensitivity analyses on an effective component of these types of dampers. After that to assessment of the damper function, an OpenSees code developed to analyze the nonlinear time history of the seven far-field selected ground motions. All the ground motions selected according to the FEMA P-695 suggested ground motions with the site class of C and the base shear, roof acceleration, story velocity and drift nonlinear time history responses of a three-story braced frame compared with and without damper. To prevent buckling of the brace members, dampers with the capacity of 90% of brace members capacity designed to use at any story brace and the maximum displacement capacity of dampers adjusted to the maximum allowable drift of the building stories. Results showed that, there are some effective and less effective parameters whose variation such as geometrical parameters can seriously change the total energy absorption level and improve the damper hysteresis loops. Also, According to the flexible design of the presented damper, if it needs to be designed with a force bearing capacity and energy absorption in accordance with the seismic design of the desired frame, it is possible to achieve the desired capacity by making changes in the overall dimensions and number of energy absorbing plates. time history responses assessment showed that using the new damper has a significant decreasing effect on the seismic responses of the building.