This paper presents a sliding mode control method for wheeled mobile robots. Because of the nonlinear and nonholonomic properties, it is difficult to establish an appropriate model of the mobile robot system for trajectory tracking. A robust control law which is called sliding mode control is proposed for asymptotically stabilizing the mobile robot to a desired trajectory. The posture of the mobile robot (including the position and heading direction) is presented and the kinematics equations are established in the two-dimensional coordinates. According to the kinematics equations, the controller is designed to find an acceptable control law so that the tracking error will approximate 0 as the time approaches infinity with an initial error. The RFID sensor space is used to estimate the real posture of the mobile robot. Simulation and experiment demonstrate the efficacy of the proposed system for robust tracking of mobile robots.
The aprotic Li-CO 2 battery is emerging as a promising energy storage technology with the capability of CO 2 fixation and conversion. However, its practical applications are still impeded by the large overpotential. Herein, the general synthesis of a series of ultrathin 2D Ru-M (M = Co, Ni, and Cu) nanosheets by a facile one-pot solvothermal method is reported. As a proofof-concept application, the representative RuCo nanosheets are used as the cathode catalysts for Li-CO 2 batteries, which demonstrate a low charge voltage of 3.74 V, a small overpotential of 0.94 V, and hence a high energy efficiency of 75%. Ex/in situ studies and density functional theory calculations reveal that the excellent catalytic performance of RuCo nanosheets originates from the enhanced adsorption toward Li and CO 2 during discharge as well as the elevated electron interaction with Li 2 CO 3 during charge by the in-plane RuCo alloy structure. This work indicates the feasibility of boosting the electrochemical performance of Li-CO 2 batteries by in-plane metal alloy sites of ultrathin 2D alloy nanomaterials.
Neurorestoratology is a newborn and emerging distinct discipline in the neuroscience family. Its establishment will definitely speed up the advance of this promising frontier realm. A worldwide association for Neurorestoratology and several official journals covering this discipline have recently been set up. Clinical practice has demonstrated that the sequelae of damages and diseases of the CNS can be functionally restored to some degree. Obstacles that hinder the promising methods of Neurorestoratology to be translated from the bench to the bedside include political, governmental, religious, ethical, economic, and scientific factors or in most instances they work in combination. Falsehoods against the recognition of neurorestoratology include: 1) no therapeutic method is currently available that suggests that it is possible to repair, even partially, neurological functions; 2) according to the media, a cure will be very soon found for patients with severe spinal cord injury, brain trauma, and progressively deteriorated CNS degenerative diseases; 3) randomizing double blind control designed studies are the only gold standard for clinical study; self-comparison designed studies should be ignored and neglected. Future directions for neurorestoratology include the comparison and integration of current and upcoming available neurorestoration methods to look for the optimization regimes, and edit and publish clinical neurorestoratology treatment guidelines.
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