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In order to improve the motion performance of compliant robots, a rotary series elastic actuator (SEA) based on arc helical springs is designed. The proposed SEA can be used to provide a wide range of flexible torsion by the combination of multi-stage rotary structures. The inner and outer double layers of springs with different stiffness are connected in series. The dynamic model of the flexible joint with the proposed SEA is established. The control law for the flexible joint is derived by the backstepping algorithm. To validate the effectiveness of the proposed SEA and the control law, the dynamic performance of the flexible joint with interference torques is simulated by Matlab and Adams. The results show that the controller can overcome the interference force and restore the balance state of the flexible joint within 0.59 s，which verifies the effectiveness of the designed elastic actuator structure and control law.

The drooping front leading edge is a simple lifting device,which can effectively reduce the aerodynamic noise and the motion space of the mechanism. It has been applied to A380 and A350XW. In order to realize the fixing rotation of drooping leading according to given requirement,it is necessary to design a drooping front mechanism type,so a design method of hinged drooping front mechanism based on four-link is proposed in this paper. According to the design input requirements,the wire frame model of the droop leading edge mechanism is established,and the kinematics and rigid-flexible coupling dynamics simulation of the mechanism are carried out. The angle variation parameters,and driving moment and the hinge point load in the mechanism are obtained. The results show that,with the uniform rotation of the driving arm,the hinged droop front can be steadily reduced by 26°,the ratio of the maximum driving torque of the two driving planes is close to 3∶2,and the lateral load at the driving position is improved by the setting of the side strut. The design of the mechanism is reasonable,and provides a good reference for the design of modern civil aircraft.

Based on the mathematical model of the elliptical cylinder, we design a new hyperchaotic map with an elliptical cylinder or a cylinder attractor. The dynamical analysis results indicate the proposed system is globally hyperchaotic, and has large Lyapunov Exponents (LEs), and high Permutation Entropy (PE) complexity. Interestingly, the hyperchaotic system exhibits the offset boosting coexistence attractors with respect to the system parameters. In addition, three Multicavity Hyperchaotic Maps (MHCM) are constructed by introducing a symmetric staircase function, which expands greatly the phase space of the system. The MHCM have more complex topological structures and maintain the chaotic performance of the original map. To illustrate the feasibility of the hyperchaotic systems further, we apply them to design a Pseudo-Random Number Generator (PRNG), and implement them on the DSP platform. [ABSTRACT FROM AUTHOR]

To meet the needs of the oil field for environmentally friendly and efficient rust removal equipment for large oil tanks, according to the specific structure of the oil tank and rust removal technology, an intelligent sandblasting and rust removal system that works on the inner wall of oil tank was designed. The system consists of a rotating truss track, special manipulator, transport trolley, wall climbing trolley and a sandblasting recovery unit outside the tank. The system improves the work efficiency and automation level of the rust removal operation and avoids dust pollution in the oil tank. The dynamics model of the system was established, and the motion state of the system components and the force condition of the load bearing wheel were analyzed through rigid-body dynamics simulation. Through the rigid-flexible dynamics simulation, the displacement trajectories of the truss track at different heights are compared, and the maximum following displacement is 16 mm, so the system can meet the performance requirements of the descaling work. [ABSTRACT FROM AUTHOR]

The genetic mutability of the influenza virus leads to the existence of drug-resistant strains which is dangerous, particularly with the lingering coronavirus disease (COVID-19). This necessitated the need for the search and discovery of more potential anti-influenza agents to avert future outbreaks. In furtherance of our previous in-silico studies on 5-benzyl-4-thiazolinones as anti-influenza neuraminidase (NA) inhibitors, molecule 11 was selected as the template scaffold for the structure-based drug design due to its good binding, pharmacokinetic profiling, and better NA inhibitory activity. As such, eighteen (18) new molecules (11a-r) were designed with better MolDock scores as compared with the template scaffold and the zanamivir reference drug. However, the dynamic stability of molecule 11a in the binding cavity of the NA target (3TI5) showed water-mediated hydrogen and hydrophobic bondings with the active residues such as Arg118, Ile149, Arg152, Ile222, Trp403, and Ile427 after the MD simulation for 100 ns. The drug-likeness and ADMET assessment of all designed molecules predicted non-violation of the stipulated thresholds of Lipinski's rule and good pharmacokinetic properties respectively. In addition, the quantum chemical calculations also suggested the significant chemical reactivity of molecules with their smaller band energy gap, high electrophilicity, high softness, and low hardness. The results obtained in this study proposed a reliable in-silico viewpoint for anti-influenza drug discovery and development.Communicated by Ramaswamy H. Sarma.

The aim of the present research work is to design a control law for a quadcopter drone based on the Virtual Attractive-Repulsive Potentials (VARP) theory. VARP theory, originally designed to enable path following by a small wheeled robot, will be tailored to control a quadcopter drone, hence allowing such device to learn flight planning. The proposed strategy combines an instance of VARP method to control a drone’s attitude (SO(3)-VARP) and an instance of VARP method to control a drone’s spatial location (R3-VARP). The resulting control strategy will be referred to as double-VARP method, which aims at making a drone follow a predefined path in space. Since the model of the drone as well as the devised control theory are formulated on a Lie group, their simulation on a computing platform is performed through a numerical analysis method specifically designed for these kinds of numerical simulations. A numerical simulation analysis is used to assess the salient features of the proposed regulation theory. In particular, resilience against shock-type disturbances are assessed numerically.