Virtual reality simulators seek to immerse users in realistic interactive environments. However, at present, while several provide kinesthetic feedback, most lack tactile feedback. Current means of tactile feedback do not generate enough force to the digits, deliver a non-intuitive sense of feedback and are too large or heavy to be used in hand-worn configurations. The tactile feedback system developed herein uses electroactive polymers to create light touch and vibratory sensation to the fingertips, and DC motors to constrict the distal digit. In essence, when current is passed through the electroactive polymer in the shape of a cantilever (7 mm long by 19 mm wide), it bends on its long axis, providing a forces of 25 mN. Vibratory feedback is created by varying input voltage with a sinusoidal waveform. To generate fingertip constriction, two DC motors cinch a wire attached to a rubber thimble. These hardware components are controlled by a computer running X3D software, an ISO standard for representing 3D graphics, which affords a virtual environment for the tracking of one’s hand. Upon contact with a virtual object, the actuators generate prescribed forces or vibrations. With this setup, a series of human-subjects experiments will be conducted whereby the task is to contact and differentiate virtual spheres of differing stiffness. Experiment 1 will test the electroactive polymers to determine the threshold for recognizing light touch, Experiment 2 will test vibrational discrimination, and Experiment 3 will test the ability of the user to differentiate constriction forces.

(далее…)

Категория: Научные статьи | Нет комментариев »

Exoskeleton systems have been largely developed in spite that quantitative performance estimation has not been reported so far. Consequently, we have been developing the wearable muscle suit for direct and physical motion supports with relevant reports on the performance. The McKibben artificial muscle has introduced “muscle suit” compact, lightweight, reliable, and wearable “assist-bots” enabling users to lift and carry heavy objects. Applying integral electromyo-graphy (IEMG), we show the results of quantitative suit performance and posture-preserving efficiency. However, for practical use, lifting seems to be one of the most important tasks for users. We improve the forearm so that the muscle suit assists the user in vertical lifting. Load carrying and lifting experi-ments show the muscle suit’s effectiveness.

(далее…)

Категория: Научные статьи | Нет комментариев »

Производство новых бронежилетов с вставками из высокомодульного полиэтилена наладили в одном из столичных НИИ. Производство новых бронежилетов с вставками из высокомодульного полиэтилена наладили в одном из столичных НИИ.

(далее…)

Категория: Амуниция | Нет комментариев »

The ankle, knee and hip all undergo stretch‐shortening cycles during human locomotion. Thus, there is potential for energy storage and return at each of these joints. It is known that joints such as the ankle and even the knee can be replaced entirely by passive mechanical substitutes and still result in highly successful performances in running and sprinting. Initial studies with apparel containing elastic elements crossing posteriorly on the hip joint to store energy during the swing phase and return energy during the stance phase indicated that vertical jumping, sprinting and running performance can be significantly improved. Tests were performed on ten elite athletes using two apparel conditions: a loose fitting t‐shirt and shorts (control) and a garment with elastic bands. Average performance benefits were up to 2% and individual benefits were over 4% for certain athletes. Many questions arise from this research:  What stiffness is required for optimal performance?  Where should the elastic elements be placed to optimize performance? For example should they be more medial or more lateral?  Where should the elastic elements be anchored for optimal performance? Building individual prototypes to answer all of these questions is very time consuming and expensive. Thus, it is desirable to design an adjustable harness or exoskeleton system that allows experimentation into the effect of these different variables (stiffness, placement, anchoring, etc. of the elastic elements). This apparatus will allow the search criteria to be narrowed to economically and functionally viable solutions that can then be implemented into apparel prototypes. In this report the process of designing the apparatus is described. The final outcome is a design using elastic belts and a design using an exoskeleton. Also side projects including EMG‐measurements, highspeed recordings of several shoes are described.

Категория: Ищем научные статьи | Нет комментариев »

This chapter presents an experimental study of upper-limb surface EMG signals and two cases of applying surface EMG signals to control an upper-limb exoskeleton robot. The applied method to process surface EMG signals to use as input information to the control method is also explained. At first, surface EMG signal extraction method and processing method are presented in this chap-ter. Then, the upper-limb muscle activities during daily upper-limb motions have been studied to enable exoskeleton robots to estimate human upper-limb motions based on EMG signals of related muscles. The muscle combinations are identified to separate some motions of upper-limb. Minimum number of muscles to extract signals to control frequent daily upper-limb motions has been identified. In the next step, EMG signal of identified muscles are used to control two upper-limb exoskeleton robots. A three degree of freedom (DOF) exoskeleton robot (W-EXOS) for the forearm pronation/supination, wrist flexion/extension and ulnar/radial deviation are controlled by applying the surface EMG signals of six muscles. Surface EMG signals of upper-limb muscles are applied as input information to control a 6DOF exoskeleton robot (SUEFUL-6). In each case of applying EMG signals experiments have been carried out to evaluate the effectiveness of the EMG based control method.

(далее…)

Категория: Научные статьи | Нет комментариев »