Powered robotic exoskeletons for assistance of human locomotion are currently under development for military and medical applications. However, the energy requirements for such devices is important and becomes an obstacle for practical applications.

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An international institution proposes an innovative exoskeleton that includes a kinematic chain of parallel pivots and comprises a shoulder, a curved and a hand. It has six degrees of freedom, with a support carried by a human operator with rigid front and rear plates. The shoulder is fixed to the front plate and the hand is fixed to a rigid glove on the operator’s hand. The active areas are controlled by flexible tendons of cables activated by control units disposed on the rear rigid plate.

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The development of HAVE applications encompasses the development of both audiovisual devices and haptic devices to deliver a higher sense of immersion in a 3D space. 2D and 3D audio technologies have been introduced to create the illusion of sound sources placed anywhere in a three-dimensional space. By processing relative left and right speaker signals, apparent sound locations can be perceived at an arbitrary point in space. Visual information in HAVE applications can be characterized by the field of view (FOV), which represents the total visible angular deviation. The FOV needs to cover between 60 and 100^∘ along the horizontal axis in order for the user to be immersed in the virtual environment. This is less than the capability of the human eye, which has an FOV range between 180 and 270^∘, depending on whether the eye is moving or not. The update rate for visual feedback is around 75Hz, and the suggested resolution is on the magnitude of 1,960 ×1,280 pixels, even though it is possible to reach 8,000 ×8,000 pixels.

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Brain-computer interfaces (BCIs) include stimulators, infusion devices, and neuroprostheses. They all belong to functional neurosurgery. Deep brain stimulators (DBS) are widely used for therapy and are in need of innovative evolutions. Robotized exoskeletons require BCIs able to drive up to 26 degrees of freedom (DoF). We report the nanomicrotechnology development of prototypes for new 3D DBS and for motor neuroprostheses. For this complex project, all compounds have been designed and are being tested. Experiments were performed in rats and primates for proof of concepts and development of the electroencephalogram (EEG) recognition algorithm.

METHODS:

Various devices have been designed. (A) In human, a programmable multiplexer connecting five tetrapolar (20 contacts) electrodes to one DBS channel has been designed and implanted bilaterally into STN in two Parkinsonian patients. (B) A 50-mm diameter titanium implant, telepowered, including a radioset, emitting ECoG data recorded by a 64-electrode array using an application-specific integrated circuit, is being designed to be implanted in a 50-mm trephine opening. Data received by the radioreceiver are processed through an original wavelet-based Iterative N-way Partial Least Square algorithm (INPLS, CEA patent). Animals, implanted with ECoG recording electrodes, had to press a lever to obtain a reward. The brain signature associated to the lever press (LP) was detected online by ECoG processing using INPLS. This detection allowed triggering the food dispenser.

RESULTS:

(A) The 3D multiplexer allowed tailoring the electrical field to the STN. The multiplication of the contacts affected the battery life and suggested different implantation schemes. (B) The components of the human implantable cortical BCI are being tested for reliability and toxicology to meet criteria for chronicle implantation in 2012. (C) In rats, the algorithm INPLS could detect the cortical signature with an accuracy of about 80% of LPs on the electrodes with the best correlation coefficient (located over the cerebellar cortex), 1% of the algorithm decisions were false positives. We aim to pilot effectors with DoF up to 3 in monkeys.

CONCLUSION:

We have designed multielectrodes wireless implants to open the way for BCI ECoG-driven effectors. These technologies are also used to develop new generations of brain stimulators, either cortical or for deep targets. This chapter is aimed at illustrating that BCIs are actually the daily background of DBS, that the evolution of the method involves a growing multiplicity of targets and indications, that new technologies make possible and simpler than before to design innovative solutions to improve DBS methodology, and that the coming out of BCI-driven neuroprostheses for compensation of motor and sensory deficits is a natural evolution of functional neurosurgery.

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We propose a framework of realizing natural assist behavior with a walking assist suit inspired by human interaction. We look at the human interaction as a behavior of synchronization action, which is a common phenomenon in walking assist between human. To achieve this human-like walking assist, synchronization based control is adopted and applied to a walking assist suit. We use neural oscillators to entrain and synchronize the assist suit’s motion with that of human user. To determine the validity and feasibility, walking experiments have conducted with a 4-DOF walking assist suit. The results showed the validity of using synchronization based control for walking assist suit.

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