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.

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Recent studies have confirmed that with a regular treadmill training walking capabilities in incomplete spinal cord injured subjects as well as in hemiplegic patients can be improved. In the beginning of this training the legs of the patients have to be assisted. So far this has been done by physiotherapists guiding the legs during gait on a moving treadmill. As this can be a very exhausting job for the therapists, the training usually is too short to get optimal results. Therefore a driven gait orthosis has been developed that can move the legs of a patient in a physiological way on a moving treadmill. The orthosis is adjustable in size so different patients can use it. There are actuators at the knee and hip joints that are controlled via a position controller. A passive foot lifter controls the ankle joint. This setup allows the legs of the patient to be moved in different, physiological gait patterns on the treadmill without any assistance of the patient or a physiotherapist. First tests with the orthosis showed good results. Several patients could be trained for more then half an hour and with a higher speed then in the manually assisted training. All trained patients reported no problems with this training; on the contrary, they felt more comfortable with the new method

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In teleoperation, force feedback is essential in making the operator to feel the same force as the slave robot for precise control with unknown environments. A new concept of the exoskeleton type master-arm is introduced. Basically, this master-arm is composed of serial links. To provide maximum range of human motion, several redundant joints are added to the serial links. Intensive graphic simulation was performed to get the optimal design parameters. In order to reduce the number of necessary joint measurement, kinematics of serial links was carefully considered in design. Three measurable, controllable joints and three free redundant joints were used for shoulder axis similar to wrist axis while one measurable, controllable axis was used for the elbow joint. For force feedback, the electric break constraints the joint movement so that the operator can feel the same force as the slave robot does. Calibration algorithm was derived to compensate the variation of the kinematic parameters. The master-arm can be used for teleoperation with a slave robot, or as a motion planner for an industrial robot

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Microorganisms are of central importance in the biodeterioration of wood by wood-boring organisms in marine habitats. We have demonstrated that shipworms attack wood that has been pre-conditioned by microbial degradation. Apparently the microorganisms function by either triggering metamorphosis or releasing an essential nutrient from the wood. We have shown that the crustacean wood-borer, Limnoria, lacks a digestive tract microflora, while the borer exoskeleton is densely colonized by bacteria. It is probable that these organisms, living in a nitrogen deficient environment on wood, use bacteria in wood and on their exoskeletonsas a nitrogen source. We are currently studying the role of bacteria in the development and survival of other wood-boring organisms. Our efforts are directed at development of effective targeted chemicals for control of wood-borers.

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Tremor is the most common of all involuntary movement. A lot of tremor patients in upper limb have serious difficulties performing daily living activities. We have developed the exoskeleton robot for tremor patient. In this paper, we focused on to develop a signal processing method to extract the voluntary movement from the electromyogram (EMG) signal in which the voluntary movement and tremor were mixed. We have researched about following two methods to recognize the voluntary movement: one is low pass filter and neural network (NN), the other is short time Fourier transform and NN. The low pass filter and neural network (NN) were effective for recognition of healthy subject’s movement. However, these methods were not applied to the tremor patient’s movement due to the characteristic oscillation of the EMG signal in the tremor patient. The proposed algorithm, which was composed of the short time Fourier transform and NN, dramatically improved the recognition rate of tremor patient’s movement. It was confirmed that the signal processing using STFT and NN is suitable for the recognition of the tremor patients. In future, we will develop more accurate algorithm based on this study, and finally conduct the clinical test to show effectiveness of our system.

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