Optimization of fracture reduction robot controller based on improved sparrow algorithm

The accuracy of a fracture reduction robot(FRR)is critical for ensuring the safety of surgery.Improving the repositioning accuracy of a FRR,reducing the error,and realizing a safer and more stable folding motion is critical.To achieve this,a sparrow search algorithm(SSA)based on the Levy flight operator was proposed in this study for self-tuning the robot controller parameters.An inverse kinematic analysis of the FRR was also performed.The robot dynamics model was established using Simulink,and the inverse dynamics controller for the fracture reduction mechanism was designed using the computed torque control method.Both simulation and physical experiments were also performed.The actual motion trajectory of the actuator drive rod and its error with a desired trajectory was obtained through simulation.An optimized Levy-sparrow search algorithm(Levy-SSA)crack reduction robot controller demonstrated an overall reduction of two orders of magnitude in the reduction error,with an average error reduction of 98.74%compared with the traditional unoptimized controller.The Levy-SSA increased the convergence of the crack reduction robot control system to the optimal solution,improved the accuracy of the motion trajectory,and exhibited important implications for robot controller optimization.

Design strategy of a high-performance multispectral stealth material based on the 3D meta-atom

In this paper,a 3D meta-atom-based structure is constructed for the multifunctional compatible design of visible,infrared,and microwave.To achieve high performance,a novel dispersion tailoring strategy is proposed.Through the incorporation of multiple controllable losses within the 3D meta-atom,the dispersion characteristics are tailored to the desired target region.The effectiveness of the strategy is verified with an error rate of less than5%.A proof-of-concept prototype is designed and fabricated,exhibiting high visible transparency,low infrared emission of 0.28,and microwave ultra-broadband absorption with a fractional bandwidth of 150%under 2.7 to18.7 GHz.This work contributes a novel design strategy for the development of high-performance multispectral stealth materials with wide applications.

Advanced liquid crystal-based switchable optical devices for light protection applications:principles and strategies

With the development of optical technologies,transparent materials that provide protection from light have received considerable attention from scholars.As important channels for external light,windows play a vital role in the regulation of light in buildings,vehicles,and aircrafts.There is a need for windows with switchable optical properties to prevent or attenuate damage or interference to the human eye and light-sensitive instruments by inappropriate optical radiation.In this context,liquid crystals(LCs),owing to their rich responsiveness and unique optical properties,have been considered among the best candidates for advanced light protection materials.In this review,we provide an overview of advances in research on LC-based methods for protection against light.First,we introduce the characteristics of different light sources and their protection requirements.Second,we introduce several classes of light modulation principles based on liquid crystal materials and demonstrate the feasibility of using them for light protection.In addition,we discuss current light protection strategies based on liquid crystal materials for different applications.Finally,we discuss the problems and shortcomings of current strategies.We propose several suggestions for the development of liquid crystal materials in the field of light protection.

Wideband diffusion metabsorber for perfect scattering field reduction

Both absorption and diffuse reflection can effectively suppress microwave backward reflection.However,the challenge of designing wideband absorptive elements with anti-phase reflection hinders the simultaneous working of the two principles.With aid of the wideband characteristic of bilateral complementary structure,we propose a strategy to design wideband absorptive elements with large reflection phase differences.For proof of concept,the proposed elements are arranged in a rectangular grid by optimizing scattering field distribution.The proposed diffusion metabsorber achieves over 20-dB scattering field reduction in the range of 8.5–20.3 GHz with good polarization stability and high angular insensitivity of up to±40°,which has been verified by real experiments.Furthermore,the proposed design strategy exhibits the potential to further reduce electromagnetic wave reflection,and the optical transparent characteristic is promising for window applications.