N. Nejatbakhsh

Tohoku University, Sendai-shi, Miyagi-ken, Japan

Are you N. Nejatbakhsh?

Claim your profile

Publications (5)0 Total impact

  • N. Nejatbakhsh, K. Kosuge
    [Show abstract] [Hide abstract]
    ABSTRACT: This work present a loose guidance method for a passive-type omnidirectional mobility aid device named Omni RT Walker-II, which its motion is performed by shared control of user and controller. Guidance is performed by division of environment to accessible and inaccessible areas and the motion of walker-user system is constrained inside the accessible area called potential canal. This paper attempts at providing evidence to the fact that loose guide method is an approach to optimal guidance in the sense that when the control (constrain) of ORTW-II motion is loose, its motion pattern significantly resembles user's unconstrained motion. Healthy user's natural motion is hypothesized to be optimal and is compared with constrained motion pattern of ORTW-II for different settings of the potential canal. Experimental results are provided and discussed
    Intelligent Robots and Systems, 2006 IEEE/RSJ International Conference on; 11/2006
  • N. Nejatbakhsh, K. Kosuge
    [Show abstract] [Hide abstract]
    ABSTRACT: A realtime path modification algorithm based on user walking ability and intent is discussed in this paper. This path planning method is being tested by a passive-type mobility aid device called Omni RT Walker-II (ORTW-II) which its motion is exclusively generated by its user, while its controller constrains undesired motion by control of four servo brakes at each wheel assembly. The Potential Canal is an accessible area of the environment in which user-walker motion is constrained. Fall prevention is the first factor which is considered in realtime modification of the potential canal. User intent in modifying the accessible are is being interpreted by a force/moment sensor and is used for realtime modification of the potential canal
    01/2006;
  • N. Nejatbakhsh, Y. Hirata, K. Kosuge
    [Show abstract] [Hide abstract]
    ABSTRACT: An omnidirectional passive walking aid system called "Omni RT Walker" (omnidirectional robot-technology walker) is proposed in this paper. Omni RT Walker consists of an omnidirectional platform with servo brake system, an onboard control unit and a frame. The system is called passive since it excludes motion generating parts such as wheel actuators and translates by force applied by its user, but includes controllable units; servo brakes in our prototype. Variable dynamics control is the control scheme applied to Omni RT Walker in order to modify its dynamic characteristics according to user's walking ability. System identification is performed to evaluate and validate this control scheme
    Advanced Robotics, 2005. ICAR '05. Proceedings., 12th International Conference on; 08/2005
  • Source
    N. Nejatbakhsh, K. Kosuge
    [Show abstract] [Hide abstract]
    ABSTRACT: This work introduces a new indoor navigation method for an omnidirectional passive walking aid system, called Omni RT Walker-II. Omni RT Walker II is the second version of a newly manufactured walking aid system with an omnidirectional platform which is controlled through merely control of MR rotary brakes and excludes actuators, aiming at higher safety and better functionality and maneuverability of the system. The proposed navigation method is unique in that it uses both environment information and human characteristics in order to provide its user with further freedom in handling the walker, and avoids abrupt movements of the system. The new method can assist the users with gait disorder and avoid turning over or falling while navigating the user to a destination. Experimental results are presented to evaluate the accuracy and quality of navigation.
    Rehabilitation Robotics, 2005. ICORR 2005. 9th International Conference on; 01/2005
  • Naemeh Nejatbakhsh, Kazuhiro Kosuge
    [Show abstract] [Hide abstract]
    ABSTRACT: This work presents a new path tracking method for a passive-type omnidirectional walking aid system, called Omni RT Walker-II (ORTW-II). ORTW-II is the second version of a walking aid system with an omnidirectional platform and uses MR brakes for its control. A new interpretation of paths, called potential canal is conducted in this paper in order to realize tracking via merely control of brakes of the passive system. Unlike most tracking methods which attempt to lead an objective system on a desired trajectory, in the new algorithm, a mobile system's motion is constrained in a pathway rather than a single trajectory and motion can be conducted by the user. In systems with direct human interaction similar to walking aid systems, the new method is expected to increase user-dependability of the system's behavior while increasing user's freedom. A collision-free potential canal is maintained using a realtime modification method, based on environmental information. Experimental results are included to evaluate the accuracy and quality of tracking.
    01/2005;