Background: Parkinson’s disease is a chronic, neurodegenerative disease characterized by gait abnormalities. Freezing of gait(FOG), an episodic inability to generate effective stepping, is reported as one of the most disabling and distressing parkinsonian symptoms. While there are no specific therapies to treat FOG, some external physical cues may alleviate these types of motor dis-ruptions. The purpose of this study was to examine the potential effect of continuous physical cueing using robot-assisted sensori-motor gait training on reducing FOG episodes and improving gait. Methods: Four individuals with Parkinson’s disease and FOG symp-toms received ten 30-minute sessions of robotassisted gait training (Lokomat) to facilitate repetitive, rhythmic, and alternating bilateral lower extremity movements. Outcomes included the FOG-Questionnaire, a clinician-rated video FOG score, spatiotemporal mea-sures of gait, and the Parkinson’s Disease Questionnaire-39 quality of life measure. Results: All participants showed a reduction in FOG both by self-report and clinician-rated scoring upon completion of training. Improvements were also observed in gait veloci-ty, stride length, rhythmicity, and coordination. Conclusions: This pilot study suggests that robot-assisted gait training may be a feasible and effective method of reducing FOG and improving gait. Videotaped scoring of FOG has the potential advantage of provi-ding additional data to complement FOG self-report.

(далее…)

Категория: Научные статьи | Нет комментариев »

This thesis presents a hierarchical geometric control approach for fast and energetically fiecient bipedal dynamic walking in three-dimensional (3-D) space to enable motion planning applications that have previously been limited to ineficient quasi-static walkers. In order to produce exponentially stable hybrid limit cycles, we exploit system energetics, symmetry, and passivity through the energy-shaping method of controlled geometric reduction. This decouples a subsystem corresponding to a lower-dimensional robot through a passivity-based feedback transformation of the system Lagrangian into a special form of controlled Lagrangian with broken symmetry, which corresponds to an equivalent closed-loop Hamiltonian system with upper-triangular form. The first control term reduces to mechanically-realizable passive feedback that establishes a functional momentum conservation law that controls the «divided» cyclic variables to set-points or periodic orbits. We then prove extensive symmetries in the class of open kinematic chains to present the multistage application of controlled reduction. A reduction-based control law is derived to construct straightahead and turning gaits for a 4-DOF and 5-DOF hipped biped in 3-D space, based on the existence of stable hybrid limit cycles in the sagittal plane-of-motion. Given such a set of asymptotically stable gait primitives, a dynamic walker can be controlled as a discrete-time switched system that sequentially composes gait primitives from step to step. We derive «funneling» rules by which a walking path that is a sequence of these gaits may be stably followed by the robot. The primitive set generates a tree exploring the action space for feasible walking paths, where each primitive corresponds to walking along a nominal arc of constant curvature. Therefore, dynamically stable motion planning for dynamic walkers reduces to a discrete search problem, which we demonstrate for 3-D compass-gait bipeds. After reecting on several connections to human biomechanics, we propose extensions of this energy-shaping control paradigm to robot-assisted locomotor rehabilitation. This work aims to oer a systematic design methodology for assistive control strategies that are amenable to sequential composition for novel progressive training therapies.

(далее…)

Категория: Научные статьи | Нет комментариев »

The present invention relates to a ungrounded, reconfigurable, parallel mechanism based, force feedback exoskeleton device for the human ankle. The primary use for the device is aimed as a balance/proprioception trainer, while the exeskeleton device can also be employed to accommodate range of motion (RoM)/strengthening exercises. This device is also used for metatarsophalangeal joint exercises.

(далее…)

Категория: Патенты | Нет комментариев »

In this research, a power-assist, lower-limb orthosis is developed to help the elderly or people suffering sports injuries walk or climb stairs. In the pneumatic muscle used for actuation, it is found that hysteresis phenomenon exists during the inflation–deflation process and such a phenomenon deteriorates the control performance. In order to eliminate the influence of hysteresis on the control system, a hysteresis model is constructed and used to devise an inverse control for feedforward compensation. The inverse control is combined with loop transfer recovery (LTR) feedback control to achieve better tracking performance. Moreover, bumpless switching compensators are also incorporated into the combined control system to ensure smooth switching between different phases of operation. To verify that the developed orthosis can effectively accomplish the assistive function, a human subject wearing the orthosis is asked to walk and to climb stairs. Experiments indicate that the orthosis is indeed helpful in assisting human locomotion.

(далее…)

Категория: Научные статьи | Нет комментариев »

This contribution presents a new approach of estimating the joint torques for an active orthosis. The new approach combines inverse dynamics and measured ground reaction forces. The joint torques can easily be computed from the ground reaction forces, but the measurement is usually awed. An obsererver is employed to estimate the disturbance of the measurements and restore the original joint torques. A model of the human lower extremity is presented and additional seat forces are introduced to model the seat. Simulation results on the Sit-to-Stand movement illustrate the eectivity of the new approach.

(далее…)

Категория: Научные статьи | Нет комментариев »