Search for: gait
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    Optimal gaits generation of a 4-legged walking robot

    , Article Proceedings of 2003 IEEE Conference on Control Applications, Istanbul, 23 June 2003 through 25 June 2003 ; Volume 1 , 2003 , Pages 664-668 Alasty, A ; Borujeni, B. S ; Sharif University of Technology
    A novel Locomotion and gait planning method for a surface walking/climbing robot based on sequential 4-bar mechanism motions is presented. The robot moves on a surface through decoupled transverse gaits and turning gaits with desired length and angle. For implementation of turning gaits three methods of Simulated Annealing Accurate Planning (SAAP), Gradient Based Planning (GBP) and Hybrid Accurate Planning (HAP) are studied. Where the last method was found the most effective approach  

    Document Biped hopping control bazsed on spring loaded inverted pendulum model [electronic resource]

    , Article Int. Journal of Humanoid Robotics ; Vol. 7, No. 2, pp. 263-280, 2010 Tamaddoni, H. (Hossein) ; Jafari, Farid ; Meghdari, Ali ; Sohrabpour, Saeed ; Sharif University of Technology
    Human running can be stabilized in a wide range of speeds by automatically adjusting muscular properties of leg and torso. It is known that fast locomotion dynamics can be approximated by a spring loaded inverted pendulum (SLIP) system, in which leg is replaced by a single spring connecting body mass to ground. Taking advantage of the inherent stability of SLIP model, a hybrid control strategy is developed that guarantees a stable biped locomotion in sagittal plane. In the presented approach, nonlinear control methods are applied to synchronize the biped dynamics and the spring-mass dynamics. As the biped center of mass follows the mass of the mass-spring model, the whole biped performs a... 

    Effects of medial thrust gait on lower extremity kinetics in patients with knee osteoarthritis

    , Article Ortopedia, traumatologia, rehabilitacja ; Volume 23, Issue 2 , 2021 , Pages 115-120 ; 20844336 (ISSN) Bokaeian, H. R ; Esfandiarpour, F ; Zahednejad, S ; Kouhzad Mohammadi, H ; Farahmand, F ; Sharif University of Technology
    NLM (Medline)  2021
    BACKGROUND: Medial thrust (MT) gait is a nonsurgical approach for reducing the knee adduction moment (KAM) in patients with knee osteoarthritis. However, its usefulness is indeterminate due to scarcity of research about changes in lower extremity kinetics and the ground reaction force (GRF) which have been investigated in this study. MATERIALS AND METHODS: Twenty patients (6 males, 14 females, age: 56.2±6.2 years) with medial knee osteo-arthritis participated in this cross-sectional study. A 12-camera motion analysis system and two force plates recorded kinematic and GRF data while participants walked barefoot along a 12m path with 1) their regular gait pattern and 2) MT gait pattern. The... 

    O 027 - There are common patterns of muscle synergy in cerebral palsy crouch gait

    , Article Gait and Posture ; Volume 65 , 2018 , Pages 55-56 ; 09666362 (ISSN) Shojaeefard, M ; Khandan, A ; Baniasad, M. A ; Farahmand, F ; Baghdadi, S ; Vafaei, A ; Narimani, R ; Sharif University of Technology
    Elsevier B.V  2018
    Background: Muscle synergy is the leading hypothesis on how the central nervous system coordinates limb functions. Cerebral palsy (CP) patients utilize fewer synergies, and are believed to have a simpler neuromuscular control. This study was undertaken to determine whether consistent muscle synergies are recruited during ambulation in cerebral palsy crouch gait and how the muscles contribute to such synergies. Methods: Ten ambulatory CP patients were recruited. All walked with crouch gait. sEMG data were collected from 14 lower limb muscles during gait analysis. Non-negative matrix factorization method was utilized to extract muscle synergies. Results and significance: A total of five... 

    Gait analysis of a six-legged walking robot using fuzzy reward reinforcement learning

    , Article 13th Iranian Conference on Fuzzy Systems, IFSC 2013 ; August , 2013 , Page(s): 1 - 4 ; ISBN: 9781479912278 Shahriari, M ; Khayyat, A. A ; Sharif University of Technology
    IEEE Computer Society  2013
    Free gait becomes necessary in walking robots when they come to walk over discontinuous terrain or face some difficulties in walking. A basic gait generation strategy is presented here using reinforcement learning and fuzzy reward approach. A six-legged (hexapod) robot is implemented using Q-learning algorithm. The learning ability of walking in a hexapod robot is explored considering only the ability of moving its legs and using a fuzzy rewarding system telling whether and how it is moving forward. Results show that the hexapod robot learns to walk using the presented approach properly  

    Kinematic and dynamic analysis of the gait cycle of above-knee amputees

    , Article Scientia Iranica ; Volume 13, Issue 3 , 2006 , Pages 261-271 ; 10263098 (ISSN) Farahmand, F ; Rezaeian, T ; Narimani, R ; Hejazi Dinan, P ; Sharif University of Technology
    Sharif University of Technology  2006
    The change of gait pattern and muscular activity following amputation is thought to be responsible for the higher incidence of joint degenerative disorders observed in amputees. Considering the lack of consistent data in the literature, the purpose of the present study was to measure and analyze the spatio-temporal variables, the kinematics and, particularly, the net joint moments of the intact and prosthetic limbs of above knee amputee subjects during walking and to compare the results with those of normals. The gait characteristics of five transfemoral amputees and five normal subjects were measured using videography and a force platform. The human body was modeled as a 2-D sagittal plane... 

    Feedback control of the neuro-musculoskeletal system in a forward dynamics simulation of stair locomotion [electronic resource]

    , Article Proc. of IMechE Part H: Journal of Engineering in Medicine ; 2009, Vol. 223, No. 6, pp. 663-675 Journal of NeuroEngineering and Rehabilitation ; Volume 11, Issue 1, 30 April 2014, Article number 78 Selk Ghafari, A. (Ali) ; Meghdari, Ali ; Vossough, Gholam Reza ; Sharif University of Technology
    The aim of this study is to employ feedback control loops to provide a stable forward dynamics simulation of human movement under repeated position constraint conditions in the environment, particularly during stair climbing. A ten-degrees-of-freedom skeletal model containing 18 Hill-type musculotendon actuators per leg was employed to simulate the model in the sagittal plane. The postural tracking and obstacle avoidance were provided by the proportional—integral—derivative controller according to the modulation of the time rate change of the joint kinematics. The stability of the model was maintained by controlling the velocity of the body's centre of mass according to the desired centre of... 

    P 043 – Center of pressure progression and ground reaction forces are altered in cerebral palsy crouch gait

    , Article Gait and Posture ; Volume 65 , 2018 , Pages 307-308 ; 09666362 (ISSN) Salehi, A ; Khandan, A ; Arab Baniasad, M ; Baghdadi, S ; Farahmand, F ; Zohoor, H ; Sharif University of Technology
    Elsevier B.V  2018

    Design and Implementation of a GAIT Analysis System Using Kinect for Clinical Application

    , M.Sc. Thesis Sharif University of Technology Jamali Soosefi, Zahra (Author) ; Behzadipour, Saeed (Supervisor)
    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 such as lower limb joints angle, stride time, stride length and spatial coordinates of joints were computed. In previous researches the Kinect sensor error has been calculated for... 

    Design and analysis of an original powered foot clearance creator mechanism for walking in patients with spinal cord injury

    , Article Disability and Rehabilitation: Assistive Technology ; Volume 14, Issue 4 , 2019 , Pages 333-337 ; 17483107 (ISSN) Maleki, M ; Badri, S ; Shayestehepour, H ; Arazpour, M ; Farahmand, F ; Mousavi, M. E ; Abdolahi, E ; Farkhondeh, H ; Head, J. S ; Golchin, N ; Mardani, M. A ; Sharif University of Technology
    Taylor and Francis Ltd  2019
    Background: The aim of this study was to assess the performance of an original powered foot clearance creator (PFCC) mechanism worn in conjunction with an isocentric reciprocal gait orthosis (IRGO) and evaluate its effect on trunk compensatory movements and spatiotemporal parameters in nine healthy subjects. Method: A PFCC motorized mechanism was designed that incorporated twin sole plates, the movements of which enabled increased toe to floor clearance during swing phase. A prototype was constructed in combination with an IRGO, and hence was re-named as an IRGO-PFCC orthosis. The effects of IRGO-PFCC usage on the spatiotemporal parameters and trunk compensatory movements during walking were... 

    Studying the Gait kinematics of Cerebral Palsy Patients Using the Uncontrolled Manifold Method

    , M.Sc. Thesis Sharif University of Technology Mohammadi, Soroush (Author) ; Farahmand, Farzam (Supervisor)
    Cerebral Palsy is the most common motor disability in childhood. It’s caused by an injury or impaired development of brain. As result, CP children have disability in motor system. All people with cerebral palsy have problem with movement. The symptoms of CP vary from person to person. Therefore, gait analysis was used to investigate those child’s problems and help therapist to find better therapy. Given that, we analyze stance phase of gait cycle of CP children. Also, we calculate and compare variability between traditional development (TD) children and CPs to find a better understanding of how central nerves system (CNS) work. Kinematic Data during walking were collected from 100 CP and TD... 

    Dynamic analysis of a 3-link biped model to investigate the rgo assisted paraplegic gait

    , Article Mobile Robotics: Solutions and Challenges - Proceedings of the 12th International Conference on Climbing and Walking Robots and the Support Technologies for Mobile Machines, CLAWAR 2009, 9 September 2009 through 11 September 2009, Istanbul ; 2010 , Pages 1121-1127 ; 9789814291262 (ISBN) Nakhaee, K ; Farahmand, F ; Sharif University of Technology
    A 3D dynamic model with 3 segments and 5 degrees of freedom (DOF) was developed to simulate the gait of a paraplegic patient while wearing a rigid orthosis. The equations of motion were formulated based on Denavit-Hartenberg notation and solved using a combined forward-inverse dynamics approach assuming locked knees, passive hips and actuated pelvis joints. Results showed that the model could take a single step in response to a sinusoidal motion applied to the pelvis joints. It was concluded that a paraplegic patient is able to walk with proper immobilization of the paralyzed joints and appropriate maneuver of the trunk, without the need to a propulsion supply from hands through crutches  

    A study on validating KinectV2 in comparison of Vicon system as a motion capture system for using in Health Engineering in industry

    , Article Nonlinear Engineering ; Volume 6, Issue 2 , 2017 , Pages 95-99 ; 21928010 (ISSN) Jebeli, M ; Bilesan, A ; Arshi, A ; Sharif University of Technology
    Walter de Gruyter GmbH  2017
    The currently available commercial motion capture systems are constrained by space requirement and thus pose difficulties when used in developing kinematic description of human movements within the existing manufacturing and production cells. The Kinect sensor does not share similar limitations but it is not as accurate. The proposition made in this article is to adopt the Kinect sensor in to facilitate implementation of Health Engineering concepts to industrial environments. This article is an evaluation of the Kinect sensor accuracy when providing three dimensional kinematic data. The sensor is thus utilized to assist in modeling and simulation of worker performance within an industrial... 

    A novel method of gait synthesis for bipedal fast locomotion

    , Article Journal of Intelligent and Robotic Systems: Theory and Applications ; Volume 53, Issue 2 , 2008 , Pages 101-118 ; 09210296 (ISSN) Meghdari, A ; Sohrabpour, S ; Naderi, D ; Tamaddoni, S. H ; Jafari, F ; Salarieh, H ; Sharif University of Technology
    Common methods of gait generation of bipedal locomotion based on experimental results, can successfully synthesize biped joints' profiles for a simple walking. However, most of these methods lack sufficient physical backgrounds which can cause major problems for bipeds when performing fast locomotion such as running and jumping. In order to develop a more accurate gait generation method, a thorough study of human running and jumping seems to be necessary. Most biomechanics researchers observed that human dynamics, during fast locomotion, can be modeled by a simple spring loaded inverted pendulum system. Considering this observation, a simple approach for bipedal gait generation in fast... 

    Studying the effect of kinematical pattern on the mechanical performance of paraplegic gait with reciprocating orthosis

    , Article Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine ; Volume 226, Issue 8 , 2012 , Pages 600-611 ; 09544119 (ISSN) Nakhaee, K ; Farahmand, F ; Salarieh, H ; Sharif University of Technology
    SAGE  2012
    Paraplegic users of mechanical walking orthoses, e.g. advanced reciprocating gait orthosis (ARGO), often face high energy expenditure and extreme upper body loading during locomotion. We studied the effect of kinematical pattern on the mechanical performance of paraplegic locomotion, in search for an improved gait pattern that leads to lower muscular efforts. A three-dimensional, four segment, six-degrees-of-freedom skeletal model of the advanced reciprocating gait orthosis-assisted paraplegic locomotion was developed based on the data acquired from an experimental study on a single subject. The effect of muscles was represented by ideal joint torque generators. A response surface analysis... 

    Design & Development of a Sit to Stand and Suspension Device for Treadmill Gait Training

    , M.Sc. Thesis Sharif University of Technology Ghannadi, Borna (Author) ; Farahmand, Farzam (Supervisor) ; Saadat Foumani, Mahmoud (Supervisor)
    A high percentage of patients with lower extremitiy disability consists of those suffer from paraplegy, hemiparety, spinal cord injuries and chronic stroke. Currently, a wast variety of methods are used for gait rehabilitation of these patients. Beside physiotherapy and different types of exercises, gait trainer systems have been devloped and used recently to help patients to obtain their walking abilities. The main goal of this work was to design and develope a device to lift a patient from sitting position on a chair to standing position in a safe and balanced mode besides obtaining enough space for physiotherapist that can easily help the patient in gait training on treadmill, also to... 

    Design and Implementation of a Body Weight Support (BWS) System

    , M.Sc. Thesis Sharif University of Technology Hamidi Rad, Mahdi (Author) ; Behzadipour, Saeed (Supervisor)
    Rehabilitation of disabled people faced some fundamental changes during past two decades. In the past, the main goal was to reduce the negative effects of disability but now various approaches are used to restore limb movement. As these people own weak muscles due to their lack of physical training, they need Intensive physiotherapy exercises to retrieve their body strength. As a consequence, rehabilitation centers are more willing to employ new ways. These new ways exert less physical pressure on physiotherapists. It helps them to be immuned from diseases like Arthritis or back injuries that is common in such servises. So the movement assisting devices can be of a great help for both... 

    Design and Implementation of Variable Impedance Control for Lower-Limb Exoskeletons with Desired Gate Refinement

    , M.Sc. Thesis Sharif University of Technology Asgari, Taha (Author) ; Vossoughi, Gholamreza (Supervisor)
    The main goal of this thesis is to develop and implement a variable Impedance control method with the ability to refine the desired gait in an online manner. For this purpose, a dataset consisting of 89 healthy gaits was utilized. Then, “Basic shapes” were driven using principal component analysis and their meaningfulness was investigated. Regarding the meaningfulness of coefficients of basic shapes, a normality metric was defined to evaluate the human gaits. Furthermore, as a reference gait refinement in Impedance control, an outer loop was added to change the desired gait, according to traversed gait. Kalman filter was used to estimate the coefficients of basic shapes in this loop. In... 

    LOKOIRAN - A novel robot for rehabilitation of spinal cord injury and stroke patients

    , Article International Conference on Robotics and Mechatronics, ICRoM 2013, Tehran ; 2013 , Pages 218-223 ; 9781467358118 (ISBN) Taherifar, A ; Hadian, M. R ; Mousavi, M ; Rassaf, A ; Ghiasi, F ; Sharif University of Technology
    This paper will focus on the design and development of a new gait training robotic device (LOKOIRAN) for patients with balance and locomotion disorders. The process of rehabilitation in this system is based on partial weight bearing system and programmable foot-plate training. The system consisted of several subsystems following: Driving and transmission system, back supporting system, leg exoskeleton, body weight support system and control system. A virtual reality environment was also designed and integrated to the system in order to motivate patients during rehabilitation protocol. The experimental tests on healthy subjects were performed to evaluate the performances of mechanical and... 

    Quantitative evaluation of parameters affecting the accuracy of Microsoft Kinect in GAIT analysis

    , Article 2016 23rd Iranian Conference on Biomedical Engineering and 2016 1st International Iranian Conference on Biomedical Engineering, ICBME 2016, 23 November 2016 through 25 November 2016 ; 2017 , Pages 306-311 ; 9781509034529 (ISBN) Jamali, Z ; Behzadipour, S ; Sharif University of Technology
    To date various commercial systems have been used in the GAIT analysis. These systems have some difficulties for clinical use, such as interfering with normal movement and high prices. The possibility of utilization of Kinect as a sensor for GAIT analysis has been studied in this research. The accuracy of Kinect in calculation of GAIT parameters such as lower limb joint angles, stride time, and stride length were computed during normal walking. The effects of the sensor's position and direction relative to the walkway were also investigated. The Kinect sensor was installed at different positions toward the motion path. In each position the data was recorded by both Kinect and a commercial...