In brain-computer interface based on motor imagery for rehabilitation, false positive could be a major cause of undesired brain plasticity which ends up with the wrong reconstruction of damaged brain tracts. Moreover, the number of electroencephalogram (EEG) electrodes required would be the reason of practical difficulties to clinical use. To reduce the false positive and the number of electrodes required, we proposed a novel two-phase classifier based on detecting Mu band event-related desynchronization (ERD). Along with five channels to detect motor imagery, the algorithm only uses three channels to reject ERD-like noise or non-motor signals. The performance of the proposed algorithm was evaluated through two-day experiments with four healthy subjects. The total sensitivity was 60.83% and the total selectivity was 78.49%. Those experimental results show that the proposed method can reduce the rate of false positives with small number of EEG channels.

This paper proposes a performance index called telepresence index for bilateral teleoperation, which can be used both for the performance evaluation of bilateral control architectures and for design purposes. This index is intended to represent a comprehensive performance objective consisting of transparency and kinematic correspondence, which are two major performance objectives of bilateral teleoperation. In order to quantify the performance objective, telepresence index has employed the error vector magnitude, which enables a seamless combination of magnitude and phase errors and the accommodation of time delay. In comparison with existing performance indices, it was observed that telepresence index possesses the comprehensiveness of performance objectives, magnitude/phase integrity, and the capacity to include time delay, which the others lack in one way or another. The index was applied to evaluate the performances of two widely known control architectures: PD-type bilateral control and Ueda's ideal control. In all cases, telepresence index has been compared favorably with the other indices in terms of clarity, convenience, and accuracy, thereby demonstrating its superiority.

In bilateral teleoperation, the performance measure has significant considerations: control objective, quantitativeness, time delay and human haptic perception, but no suitable performance measure exist. Therefore this paper investigates extended transparency as a performance measure in bilateral teleoperation. First, through an analysis based on control objective, extended transparency has two independent control objectives: trackability and immersivity. Second, we develop the performance measure for each control objective of extended transparency by using both the transmission delay constant and the error vector magnitude for the effect of time delay, and both the meaningful perception bandwidth and the compliance just-noticeable-difference for human haptic perception. Finally, extended transparency is applied to two kinds of control architecture in a one-DOF LTI teleoperation system. The case study and simulations demonstrate the ease of application and the validity of the proposed method.

This paper presents significance of causality analysis in attaining transparency of bilateral teleoperation. The causality analysis enabled novel understanding of teleoperation systems, thereby providing methods for finding transparency-attainable control architectures with proper control parameters. Furthermore, when combined with the causality-based stability, stability could still be guaranteed while attaining transparency. Experimental verification is given for simple 1-DOF teleoperation tasks.

This paper investigates transparent teleoperation using two-channel control architectures. First, we show the transparency attainability using hybrid parameters and present transparency conditions according to each class of two-channel control architectures. In addition, for real implementation, the following practical solutions are introduced: design guidelines for control parameters to reduce the effect of impedance estimation error, and a hybrid control law based upon time delay control for unknown impedance. Finally, the proposed scheme is applied to a haptic simulation using a 1-DOF master and a teleoperation task using a 2-DOF master-slave system. The experimental results show the validity of the theoretical works.