Американская компания Lockheed Martin приступила к биомеханическим испытаниям экзоскелета HULC, сообщает Defense Aerospace. В испытаниях, длительность которых составит семь недель, принимают участие военнослужащие Армии США. Целью проверки является оценка влияния экзоскелета на организм человека. После проведения испытаний Lockheed Martin намерена изменить конструкцию HULC в соответствии с пожеланиями военных.

(далее…)

Категория: HULC | Нет комментариев »

A human with muscle weakness can wear a rehabilitation device, e.g. exoskeleton, to receive support during walking. However, how can this support be adjusted in real-time to the intention of the user? The given support should be intuitive, user-specific, compliant and robust to sensor noise. We suggest the use of an adaptive oscillator which can detect the frequency and phase of the user’s gait. The designed oscillator-based controller is capable to adjust the support in real time, based on reliable joint angle measurements. The adaptive oscillator determines the position and velocity reference trajectories, based on the measured joint angles. The controller uses these reference trajectories to attract the current angle respectively velocity. This is part II of a two-part paper. In part I of this paper the controller is optimized using simulations. In part II the performance of the optimized oscillator-based controller is determined for the ankle joint using specially designed pneumatic ankle foot orthoses (PAFO). The PAFO actuate the plantar exion movement with pneumatic muscles. The performance of the controller is analyzed measuring the activity of the Tibialis Anterior and Gastrocnemius Medialis with electromyography (EMG). The oscillator-based controller found the same reference joint angles and velocities in real time compared to the optimization. The desired exoskeleton torques are comparable to the simulations, but the amplitude is lower. The support decreased the EMG activity of the Gastrocnemius Medialis. However, the lack of transparency of the PAFO increased the EMG of the Tibialis Anterior. Overall the oscillator-based controller can give a user-specic support by detecting the gait frequency and learning the gait trajectory. The specially designed PAFO can measure the performance of controllers on humans objectively. The EMG of the Gastrocnemius Medialis can decrease more, when the transparency of the PAFO is increased.

(далее…)

Категория: Научные статьи | Нет комментариев »

Video games can be mesmerizing, even for a rhesus monkey. Which may explain, in part, why 6-year-old Jasper has been sitting transfixed at a computer screen in a Washington University lab for nearly an hour, his gaze trained on a small red ball. A more interesting reason for Jasper’s quiet demeanor is that he is hurling the ball at a moving target using just his thoughts.

Категория: Ищем научные статьи | Нет комментариев »

For a robotic system, the complete description of the end-effector motion requires six independent parameters, while the desired end-effector motion for a task often needs less than 6 d.o.f. Therefore, the end-effector motion can be divided into desired motion and undesired motion. The end-effector motion is transformed from the joint motions. In this paper, the efficiency of the joint motions to implement the desired motion is investigated and a new concept called motion purity is proposed to measure this efficiency. The new concept is more comprehensive and direct than other existing performance measures, such as the volume of workspace and manipulability. It is appropriate as a design objective at various phases in designing a robotic mechanism. The tripod machine tool is studied and its structure is optimized from the viewpoint of the motion purity.

Категория: Ищем научные статьи | Нет комментариев »