Based on pneumatic artificial muscles, the force feedback dataglove is an important interface designed for dexterous manipulations with virtual environments, which provides force display for every segment of the thumb, index and middle finger. The typical mechanism of exoskeleton structure is adopted to allow full range-of-motion of the hand, with the actuator system placed on the forearm. The exoskeleton structure also serves as the hand position measurement function, by integrating non-contact Anisotropic Magneto-resistive sensors. The actuator consists of the pneumatic muscle and brake system. The contracting force of muscle transmitted through the tendon sheath structure is measured by the cantilevered beam sensor installed inside the pedestal. The single PC-based control interface comprises of an industrial computer, pneumatic valves and electronic ISA-bus cards for reading the sensors and implementing pressure control. The grasping force calculated according to the object deformation as well as its modeled compliance is displayed to the finger by regulating the pressure in the muscles based on the isometric characteristics

Категория: Ищем научные статьи | Нет комментариев »

This paper presents a new portable exoskeleton design for superior limbs by the CEA-LIST laboratories. The first model described here (4 axis) is designed to apply forces in 3 directions. The first application is foreseen as an assistance device to enable a disabled person to carry an object such as a teapot or water bottle. It is designed as a base for more complete systems. A partial realization of it is presented for the first time. The high potential of the actuators used both in terms of back drivability and force capacity, allows hybrid force-position control laws making it possible to cover a broad range of applications: rehabilitation, assistance, force feedback master arm for telerobotics, sport training, and a virtual reality workbench

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This paper presents the design and the optimal dimensional synthesis of a reconfigurable, parallel mechanism based, force feedback exoskeleton for the human ankle. The primary use for the device is aimed as a balance/proprioception trainer, while theexoskeleton can also be employed to accommodate range of motion (RoM)/strengthening exercises. Multiple design objectives for several physical therapy exercises are discussed and classified for the design of the rehabilitation device. After kinematic structures of mechanisms that are best suited for the physical therapy applications are selected, an optimization problem to study the trade-offs between multiple design criteria is formulated. Dimensional synthesis is performed to achieve the maximum stiffness of the device, while simultaneously maximizing the actuator utilization, using a Pareto-front based framework. An ldquooptimalrdquo design is selected studying the Pareto-front curve and taking the primary and secondary design criteria into account. Once the dimensions of the device are decided, reconfigurability is built into the design such that the device can be arranged as a 3UPS manipulator to administer RoM/strengthing exercises and as a 3RPS manipulator to support balance/proprioception training. Metatarsophalangeal joint exercises are also enabled through a reconfigurable design of the foot plate. Details of the final design of the ankle exoskeleton, CAD snapshots, and an early prototype of the device are also presented.

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In this paper, a new type of master finger in exoskeleton type has been developed to implement master-slave operation for DLR/HIT dexterous hand. The finger has three novel characteristics. Firstly, the exoskeleton mechanism uses ldquofour-bar mechanism jointrdquo, which rotates about an instant center that coincides with joint center of operator’s finger. Secondly, the master finger can distinguish the contact and non-contact mode. The two modes enable free motion and natural contact sensation between operator and master finger respectively. Thirdly, the master finger can exert forces in the direction of extension and flexion because it can make active motion in the two directions. In order to assure faster data transmission and near zero delay in master-slave operation, a digital signal processing/field programmable gate array (DSP/FPGA-FPGA) structure is proposed to control the master finger. The kernel of the hardware system consists of a peripheral component interface (PCI)-based DSP/FPGA board configured as high-level and a FPGA board configured as low-level. By utilizing low-voltage differential signaling (LVDS) serial data bus and PCI bus, the high-level can communicate with the low-level and PC. Using the principle of Virtual work, the relationship between driving torque and the force acting at the tip of master finger is acquired and validated by an experiment conducted to the operation of master finger and DLR/HIT dexterous finger. Experimental results also demonstrate that the master finger can augment telepresence.

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This paper introduces a novel type of actuator that is investigated by ESA for force-reflection to a wearable exoskeleton. The actuator consists of a DC motor that is relocated from the joint by means of Bowden cable transmissions. The actuator shall support the development of truly ergonomic and compact wearable man-machine interfaces. Important Bowden cable transmission characteristics are discussed, which dictate a specific hardware design for such an actuator. A first prototype is shown, which was used to analyze these basic characteristics of the transmissions and to proof the overall actuation concept. A second, improved prototype is introduced, which is currently used to investigate the achievable performance as a master actuator in a master-slave control with force-feedback. Initial experimental results are presented, which show good actuator performance in a 4 channel control scheme with a slave joint. The actuator features low movement resistance in free motion and can reflect high torques during hard contact situations. High contact stability can be achieved. The actuator seems therefore well suited to be implemented into the ESA exoskeleton for space-robotic telemanipulation

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