The work presents a newly developed safety concept for application of robotic walking simulators based on the principle of programmable footplates in gait rehabilitation. Unlike robotic hand devices or exoskeleton robots for gait training on treadmills, which can be built relatively lightweight and require only small drives which can hardly do harm to the patient, a programmable footplate walking simulator with permanent foot fixture essentially needs to have powerful drives in order to carry and move the full body weight of the patient. The developed safety concept comprises several redundant algorithms and devices in the real-time robot control software, electrical emergency stop circuitry and machine mechanics. The mechanical core is a machine design offering maximum passive security by covering all moving parts (i.e. robot drives and linkages) and a newly developed foot safety release binding, which is mounted on each footplate. The release binding allows a safe release from the footplate in all directions in any degree of freedom in the sagittal plane. It is combined with an ankle goniometer which is equipped with adjustable emergency stop limit switches, thus ensuring that the allowed ankle range-of-motion is not exceeded.

Категория: Ищем научные статьи | 1 Комментарий »

Insects of the order Diptera have evolved to become prolific flyers able to perform aerial maneuvers that far surpass anything man-made. The Harvard Micro robotics lab has recently demonstrated the first step towards recreating these evolutionary wonders with the world’s first demonstration of an at-scale robotic insect capable of generating sufficient thrust to takeoff (with external power). The mechanics and aerodynamics of this device are quite similar to Dipteran insects. Biologists have recently quantified the complex nonlinear temporal phenomena that give insects their outstanding capabilities. Periodic wing motions consisting of a large stroke and pronation and supination about an axis parallel to the span-wise direction are characteristic of most hovering Dipteran insects. Previous microrobot designs have attempted to concisely control each wing trajectory in these two dimensions. The robot that is shown here has three degrees-of- freedom, only one of which is actuated. Here, a central power actuator drives the wing with as large a stroke as possible and passive dynamics allow the wing to rotate using flexural elements with joint stops to avoid over-rotation. There are four primary components to the mechanical system: the actuator (or ‘flight muscle’), transmission (or ‘thorax’), airframe (or ‘exoskeleton’) and the wings. Each is constructed using a meso- scale manufacturing paradigm called Smart Composite Microstructures. This entails the use of laminated laser-micromachined materials stacked to achieve a desired compliance profile. This prototyping method is inexpensive, conceptually simple, and fast: for example, all components of the fly can be created in less than one week. Additionally, the resulting structures perform favorably when compared to alternative devices: flexure joints have almost no loss, ultra-high modulus links have higher stiffness-to-weight than any other material, and the piezoelectric actuators have similar power density to th- e best DC motors at any scale. After integration, the fly is fixed to guide wires that restrict the motion so that the fly can only move vertically. The wings are then driven open loop to achieve a large angular displacement. This is done at resonance to further amplify the wing motion. The wings exhibit a trajectory nearly identical to biological counterparts. Finally, this 60 mg, 3 cm wingspan system is allowed to freely move in the vertical direction demonstrating thrust that accelerates the fly upwards. Bench-top thrust measurements show that this robotic fly has a thrust-to- weight ratio of approximately two. These results unequivocally confirm the feasibility of insect-sized MAVs. The remaining challenges involve the development of microelectronics appropriate for power conversion, sensing, communication, and control along with the choice of an appropriate power source.

Категория: Ищем научные статьи | Нет комментариев »

Exoskeletons are wearable robots exhibiting a close cognitive and physical interaction with the human user. These are rigid robotic exoskeletal structures that typically operate alongside human limbs. Scientific and technological work on exoskeletonsbegan in the early 1960s but have only recently been applied to rehabilitation and functional substitution in patients suffering from motor disorders. Key topics for further development of exoskeletons in rehabilitation scenarios include the need for robust human-robot multimodal cognitive interaction, safe and dependable physical interaction, true wearability and portability, and user aspects such as acceptance and usability. This discussion provides an overview of these aspects and draws conclusions regarding potential future research directions in robotic exoskeletons.

Категория: Ищем научные статьи | Нет комментариев »

Walking power-assisted robot is a wearable exoskeleton leg for augmentation of the human walking ability. It is anthropomorphic, parallels to the human lower limbs and interfaces to the human via shoulder straps, waist belt, thigh cuffs, and a shoe connection such that the geometry of the human and the machine approximately match one another. It is important and necessary for analyzing the human walking gait in order to reality the power-assisted robot walking coincident with the operator, and human walking gait data will provide some useful bases for the design of power-assisted robot. So in this paper we focus on introducing the walking gait analysis system which we have developed.

Категория: Ищем научные статьи | Нет комментариев »

Numerous researches have been carried out to use robot in the area of stroke rehabilitations. The conventional approach is to assist patient to perform Activities of Daily Living (ADL) through a set of pre-programmed trajectories. The main drawback lies in the lack of voluntary movement by the patient. Many of these works have been carried out by using positional feedback control. In this kind of system, it is difficult to assess patient’s muscle condition, which may results in inconveniences due to torques or forces asserted by the rehabilitation robot. The main aim of the project is to build a stroke rehabilitation system using socially inspired robot technique. The system monitors patient’s muscle activity and uses this information to drive an exoskeleton robot that will assist patient to his/her arm. Movement is generated based on voluntary muscle activity by patient and therefore will improve their learning curve. Another main advantage is the system minimizes patient’s inconveniences due to movement by robot. The system is based on torque feedback control. A sliding mode control was implemented in replace of conventional control. The main advantage of sliding mode control over conventional control is its robustness. Sliding mode control does not require precise mathematical model of the system and it is insensitive to parametric changes and uncertainties within the system.

Категория: Ищем научные статьи | 1 Комментарий »