In this paper, the dynamics-based high-performance robot motion control technology has been mainly studied, and the overall structure is controlled via dynamics forward, given the nonlinearity, strong coupling and time-variability of robots. Considering the unavailability of precise robot model parameters and the uncertain disturbance in real operation, we put forward an active disturbance rejection control (ADRC) strategy based on dynamic feedforward, aiming to improve the control robustness and combining the simple structure, strong anti- disturbance ability, and no restriction from the control model of ADRC. Given the multi-joint coupling of robots, controlled decoupling is conducted by using dynamic characteristics. The ADRC cascade control structure and algorithm based on dynamic feedforward have been studied and the closed-loop stability of the system is investigated by analyzing the system dynamic linearization compensation and the anti-disturbance ability of the extended state observer. Experiments have shown the new strategy is more robust over uncertain disturbance than the conventional proportional-integral-derivative control strategy.

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A 360-area surface-based cortical parcellation is extended to study mild cognitive impairment (MCI) and Alzheimer's disease (AD) from healthy control (HC) using the joint human connectome project multi-modal parcellation (JHCPMMP) proposed by us. We propose a novel classification method named as JMMP-LRR to accurately identify different stages toward AD by integrating the JHCPMMP with the logistic regression-recursive feature elimination (LR-RFE). In three-group classification, the average accuracy is 89.0% for HC, MCI, and AD compared to previous studies using other cortical separation with the best classification accuracy of 81.5%. By counting the number of brain regions whose feature is in the feature subset selected with JMMP-LRR, we find that five brain areas often appear in the selected features. The five core brain areas are Fusiform Face Complex (L-FFC), Area 10d (L-10d), Orbital Frontal Complex (R-OFC), Perirhinal Ectorhinal (L-PeEc) and Area TG dorsal (L-TGd, R-TGd). The features corresponding to the five core brain areas are used to form a new feature subset for three classifications with the average accuracy of 80.0%. Results demonstrate the importance of the five core brain regions in identifying different stages toward AD. Experiment results show that the proposed method has better accuracy for the classification of HC, MCI, AD, and it also proves that the division of brain regions using JHCPMMP is more scientific and effective than other methods.

Power amplifier is the key component of the magnetic bearing systems, and its precision characteristics have decisive influence on the overall performance. We analyze the factors in the formation of precision characteristics of typical digital switching power amplifier under two-level modulation, and reveal that the inherent ripple characteristic and precision of current detection are the main limits. The relationships between inherent ripple characteristic and its main influencing factors, such as bus voltage, modulation frequency and constants of electromagnetic coil have been derived in this paper. By suppressing the analog noises and drifts in current detection circuit, and calibrating the analog to digital converter, the precision performances of the current detection circuit had been improved efficiently to avoid becoming the dominant factor of the formation of the precision characteristics, which make that the precision of output current is nearly determined by the inherent ripple characteristic. The experimental results show that the output current ripple is very close to the inherent ripple characteristic if the precision of current detection circuit is high enough. Furthermore, the approaches discussed can describe the formation of precision characteristics by theoretical calculation of inherent ripple characteristic under the conditions of different implementations.