Sharif Digital Repository

Lack of force feedback during minimally invasive procedures is one of the downsides of such interventions and might result to excessive damage to surrounding tissues. The goal of the present research is to introduce a vision-based approach to estimate contact forces on soft tissues. In this approach, a model was developed in which, image of deformation of a sample soft tissue, under the jaws of laparoscopic gripper, is the input and the output is the gripper force. In this work, a FEM of soft tissue in contact with jaws of a laparoscopic tool is developed. . In the model, the effects of friction between the tool and tissue is considered which was not included in the previous studies. After... 

The idea of using master_salve robot in Surgical, entered the medical science in a new phase.The surgeon uses the master to perform arbitary actions and slave follow the movements of the master robot in the envirement.To increase the accuracy, it is necessary to transfer information between the robots in both directions, from master to slave and vice versa, that means bilateral teleoperation. But time delay is a serious problem for bilateral teleoperation systems. Even a small time delay will generally degrade the system’s performance and cause instability.Wave variable method based on passivity and scattering theory is an important approach that guarantees stability in the presence of any... 

In recent years, the national health systems have supported the idea of home-based rehabilitation, since receiving cares at hospital environments is too expensive both in money and time. This method reduces the patients’ commuting to the clinics. Moreover, it enables them to practice the prescribed movements at any time.Most of the existing systems compute the patient’s motion performance in a zero-one manner which does not distinguish any small progress in his condition. Thus, a non-task based method which can assess precisely the patient’s level is yet missing. This project aims to develop a set of motion performance indices which can judge the upper limb motions in a home-based... 

Nowadays the process of making smart rehabilitations' equipment is at the centre of physicists' attention, so this affair is a matter of research in the medical engineering.Amongst of the advantages of this method there are: increasing the efficiency, recording patients' information, no need for continuous physiotherapists and therapists' presence in all the process of medical treatment, and saving time and money. In addition, due to removing traditional methods of rehabilitation, the precision and control ability of medical treatment is considerably increased, reducing the unexpected injuries during the exercise. The shoulder wheel is one of the useful devise in clinics physiotherapy... 

To date various commercial systems were used in the gait analysis area. These systems have some difficulties for clinical use, such as being indwell, making trouble in movement and high prices. The Kinect sensor does not have problems of these systems. If the error of sensor is acceptable, Kinect sensor is a suitable choice for application in clinics. The possibility of utilization of the Kinect sensor as a gait analysis system has been studied in this research. The sensor errors in calculation of gait parameters for lower limb joints angle were computed. In previous researches the Kinect sensor error has been calculated for upper limb joints angle and the subject was standing motionless in... 

The Coronary artery bypass grafting surgery is one of the most complicated and invasive surgeries, in which the chest is cleaved up to 20 cm. Also, heart motion with 1-2Hz frequency bothers surgeons to perform on. This leads surgeons to get interested in minimally invasive robotic surgery methods. The idea is to synchronize the robot motion with heart, in order for surgeons to perceive it stationary. This needs 3 major stages: online taking of data, estimate the future heart motion, and control the robot. First studies employ visual seroving for control demand. Later studies, although differ in data collection methods, rely on classic error-based feedback controllers, such as PID. Fast... 

Nowadays, stroke is known as one of the main reasons for death and disability. Statistical researches have shown that the number of stroke survivors is growing. Assessing stroke stage is one of the vital requirement of effective rehabilitation. Since the recent decades, new methods to assess upper extremity movement quality based on movement kinematic have been proposed in the literature. These methods quantify movement quality with the use of kinematic indices. In this study, repeatability and reliability of the proposed indices have been evaluated in a functional motion of daily activity consisted of diverse tasks. In this study, calculations were done on captured data of hand's movement... 

Parkinson’s disease (PD) is a neurodegenerative disorder and during the last few years considerable measures have been taken to rehabilitate its patients. To prevent the disorder from deteriorating and to control its progress, patients have to undergo some therapy sessions that incorporate some mobility exercises e.g. walking, sitting up and down, and etc. Since transporting the patients to the clinical centers is too burdensome, growing attention is drawn towards telerehabilitation. To this end, DMRCINT has developed a telerehab system for PD patients. This system is an intelligent classifier that uses features of linear acceleration and angular velocity signals to detect the activity that... 

Human Activity Recognition (HAR) has had tremendous improvements in the field of elderly monitoring and telerehabilitation. An anchor point for HAR systems in telerehabilitation is supervising rehabilitative excercises. For Parkinson’s disease (PD) patients, a group of rehabilitative activities, known as Lee Silverman Voice Treatment-BIG, or LSVT-BIG, have shown to be effective in improving motor performance. Similar to any rehabilitative measure, delivering these activities requires the supervision of an expert or clinician, so that the patient receives proper feedbacks. HAR systems can replace human experts. They can recognize activities and provide the user with proper feedback. HAR... 

In recent years, there has been an increasing interest in posturography methods as an objective quantitative tool for assessing balance and indicating patient with high risk of fall. Although many posturographic studies tried to describe balance deficiencies in PD, little success has been achieved in utilizing static posturography as a tool for discriminating faller and non-faller PD patients. Furthermore, Dynamic posturography studies have delivered valuable insight into the potentiality of these methods for assessing balance, but these devices are very high in price and cumbersome to move that can limit the feasibility of their use in the clinical settings. The aims of this study were: 1)... 

Exoskeleton is a newborn technology for disabled people. Personal exoskeleton is a type that is suitable for replacement of wheelchair. Exoped, the first Iranian exoskeleton made by Pedasys company, was a rehabilitation one. The purpose of this research was enhancing the design of its actuators to accomplish lighter, smaller and cheaper one. At first we identified the different loads that are applied to actuators of exoskeleton and we tried to decrease the number of actuators needed, as more as possible. Then we modeled the exoskeleton-user system to measure the required parameters. Using this model, we conducted an algorithm to design appropriate gait cycle for walking with the help of... 

User comfort in wearable robots and precise limb tracking of the robots' links can be considered as general and significant indicators of the robots' performance. On the other hand, due to the kinematic mismatches between the human body and conventional wearable robots, which often occur due to various reasons such as the kinematic differences between the body and robot joints (e.g. the knee joint), it seems unlikely to achieve a robot in which user's limbs comfortably follow its link without tracking error. In this study, in order to evaluate and improve the performance of the robot, two performance indices: limbs tracking error index (TEI) and user discomfort index (DI) were introduced,... 

Parkinson's disease is a destructive and long-term disease of the central nervous system. This disease especially affects the motor system. Parkinson's patients can be studied under dopaminergic and non-dopaminergic conditions. The non-dopaminergic state means not taking the drug, for at least 12 hours, and the dopaminergic state, from one hour to less than 12 hours after taking the usual dose of the dopaminergic drug. The aim of this study is to examine and compare the statistics and characteristics of Parkinson's patients in dopaminergic and non-dopaminergic states, focusing on reaching and tracking activities. It also aims to analyze the differences before and after rehabilitation in... 

One of the appropriate and efficient methods to restore walking ability due to spinal cord injury is the use of exoskeletons with active joints (actuated joints), also known as wearable robots. These tools, along with their many advantages, present challenges that can affect their performance. One of the existing challenges is how to connect these robots to the body. This connection determines the amount and manner of applying force and torque from the robot to the body parts, and plays a significant role in the performance of these robots, user compliance, and user comfort. Therefore, examining the interfaces between the robot and the body and identifying the parameters that affect their... 

Walking with lower-limb exoskeletons, particularly in individuals with limited motor abilities, presents numerous challenges. One of the most critical limitations is the absence of an active ankle joint in many commercial exoskeletons. This deficiency prevents users from naturally transferring their center of mass over the peak of potential energy, as the ankle normally plays a crucial role in generating forward propulsion and transferring energy between steps. The lack of this energy source forces users to adopt compensatory strategies that have not yet been thoroughly identified or analyzed. In this study, aiming to precisely analyze the gait mechanism in the presence of an exoskeleton... 

In this study, a forward dynamics model of the human–lower limb exoskeleton system (ExoPed model) incorporating an instrumented cane was developed to enable simulation of user–system biomechanical interactions and comparison with experimentally measured data. First, a cane equipped with a uniaxial load cell was designed and implemented, capable of measuring the axial force in real time and transmitting it wirelessly to a computer. Subsequently, motion data of the user wearing the exoskeleton and using the cane were collected through a precise marker-based protocol using a three-dimensional motion capture system during walking trials. A full-body dynamic model, including the upper body, lower... 

One of the effective methods for restoring motor abilities in patients with spinal cord injury is the use of lower-limb exoskeleton robots. The design of these robots faces multiple challenges, including the selection of mechanical parameters, control algorithms, and the motion patterns of active joints. The common approach for determining these parameters has been trial and error, which is both costly and time-consuming. Therefore, the use of computational models and numerical simulations has emerged as a more efficient alternative. However, most of the models developed in previous studies have been based on inverse dynamics, meaning that the motion data of the user and the robot were given... 

Each year, from %30 to %60 of the elderlies fall down. %10 to %20 of these incidents result in severe injuries. Aging along with stroke can possibly damage body balance system temporarily or permanently. Therefore, human body balance system improvement and treatment seems necessary. Physical therapy methods relying on assistance require not only physiotherapist presence, but also considerable amount of money and time for both patient and physician. Thus, novel rehabilitation methods that do not require physiotherapist presence can help patients greatly. To do so, an apparatus has been designed and fabricated at Sharif University of technology. This apparatus can produce the active... 

Each year from %30 to %60 of the elderlies fall down. %10 to %20 of these incidents result in severe injuries. Aging along with stroke can possibly damage body balance system temporarily or permanently. Therefore, human body balance system improvement and treatment seems necessary. Physical therapy methods relying on assistance require not only physiotherapist presence, but also considerable amount of money and time for both patient and physician. Thus, novel rehabilitation methods that do not require physiotherapist presence can help patients greatly. To do so, an apparatus has been designed that— using force plate— enables mass center detection as well as visual report to patient. The... 

Paralysis is one of the most common disabilities resulting from stroke. Usually injury to one hemisphere of the brain affects the opposite side of the body. This one-sided paralysis is called hemiplegia Damage to a lower part of the brain, the cerebellum, can affect the body's ability to coordinate movement, a disability called ataxia, leading to problems with body posture, walking, and balance. Reaching tasks are building blocks of most daily functional movements. The purpose of such a movement is to transfer a specific point of hand (e.g. fingertip) toward a special location in space around. In people with ataxia, trajectories of reaching movements are far different from healthy people in...