偏瘫患者辅助下肢外骨骼设计与仿真分析

针对偏瘫患者外骨骼康复机器人降低外骨骼质量的要求,设计了一种辅助下肢外骨骼机器人,采用柔索驱动的膝关节,具有结构简单,质量轻的特点。同时利用ADAMS建立了外骨骼关节柔索驱动的动力学模型,绳索模块建立了柔索驱动模型,通过Ariel生物运动分析软件,采集髋、膝、踝关节运动数据,运用Spline函数进行了仿真分析。经过仿真分析柔索驱动在上台阶运动过程中的不同拉簧预紧力和拉簧刚度下传动特性和驱动力矩,为进一步研究设计下肢外骨骼提供依据。     

士兵可穿戴下肢外骨骼机器人多元感知方法研究

下肢外骨骼机器人是一种可穿戴且融合了多种机器人技术的复杂人-机系统。它将人类的智慧与机器人强壮的能力有效地结合起来,最大限度地提高人体的机动力和耐力,这为提升单兵作战系统的能力创造了条件。鉴于下肢外骨骼机器人在作战、后勤保障时可能遇到的复杂地形、多变随机的任务等,仅通过基于既定的典型步态规划程序驱动执行已知的特定动作,难以保证人机间的耦合性和动作的高随意性切换。为此,模拟并提炼出士兵常见的六种下肢动作作为后续研究,然后分析了下肢外骨骼机器人的感知控制原理,并提出了基于脑电预判感知、肌电精确感知和光纤实时校正的多信息融合的感知方法,强调将人的智能参与到机器人控制中,以期推进士兵可穿戴下肢外骨骼机器人的实用化。     

基于DMFC的上肢外骨骼人—机协调控制系统

上肢外骨骼人—机协调控制系统中的一个关键问题是直角坐标系中的力信号转换成联合坐标系中力矩,该过程中奇点几乎一直存在。为了解决这个问题,提出了一种基于动态模型力控制器(dynamic model of force control, DMFC)的控制系统。利用阻尼最小二乘法处理负载,转矩补偿负载质量,避免了奇异性。在外骨骼的末端执行器处安装力传感器用于测量外骨骼和负载之间的力,通过相互作用力自动反映使用者的运动意图。实验结果表明,提出的控制系统具有非常好的稳定性和可负载性,当施加负载补偿时,不附加任何物体与附加5公斤对象的外骨骼末端执行器位置之间的稳态误差可减小至0.01 以下,完全满足起吊重物的上肢外骨骼需求。     

Biohybrid bacterial microswimmers with metal-organic framework exoskeletons enable cytoprotection and active drug delivery in a harsh environment

The inspiring idea of using motile bacteria as bioengines to create biohybrid microswimmers has been realized by integrating functionalized cargos with bacteria recently. However, existing pernicious factors in ambient conditions, such as enzymes, may attack bacterial microsystems when they are executing tasks. Here, a versatile bacterial microswimmer system with cytoprotective metal-organic framework (MOF) exoskeletons is reported, capable of protecting the bioengine from enzyme degradation. Zeolitic imidazolate framework-8 (ZIF-8) nanoparticles (NPs) are fully coated on the surface of motile bacteria (Escherichia coli MG1655) through tannic acid (TA) complexation. The ZIF-8 wrapping is demonstrated with negligible influence on bacterial motility under optimized conditions. Moreover, ZIF-8@E. coli microswimmers still maintain their shapes and motion performance in the presence of lysozyme, verifying the effective preservation of formed ZIF-8 exoskeletons on the bacterial surface. Coupling with the drug loading capacity of ZIF-8, Doxorubicin (DOX)-loaded ZIF-8@E. coli microsystems retain their effective propulsion after being treated with lysozyme, enabling the accelerated crossing through the Transwell membrane and improving anticancer efficacy compared with passive drugs. The fabricated bacterial microswimmers were also verified with chemotactic motion and prolonged retention time in the mouse bladder, holding great potential to design an active medical platform with improved therapeutic efficacy for targeted disease treatment, such as bladder cancer. Combining bacteria with MOFs generates multifunctional biohybrid microswimmers with capabilities of cytoprotection and active drug delivery. Such design facilitates the development of active biosystems to apply in harsh environments and meets rigorous requirements in clinical biomedical applications.     

Chitosan Films Obtained from Brachystola magna (Girard) and Its Evaluation on Quality Attributes in Sausages during Storage

High molecular weight chitosan (≈322 kDa) was obtained from chitin isolated from Brachystola magna (Girard) to produced biodegradable films. Their physicochemical, mechanical and water vapor permeability (WVP) properties were compared against commercial chitosan films with different molecular weights. Brachystola magna chitosan films (CFBM) exhibited similar physicochemical and mechanical characteristics to those of commercial chitosans. The CFBM films presented lower WVP values (10.01 × 10⁻¹¹ g/m s Pa) than commercial chitosans films (from 16.06 × 10⁻¹¹ to 64.30 × 10⁻¹¹ g/m s Pa). Frankfurt-type sausages were covered with chitosan films and stored in refrigerated conditions (4 °C). Their quality attributes (color, weight loss, pH, moisture, texture and lipid oxidation) were evaluated at 0, 5, 10, 15 and 20 days. Sausages covered with CFMB films presented the lowest weight loss (from 1.24% to 2.38%). A higher increase in hardness (from 22.32 N to 30.63 N) was observed in sausages covered with CFMB films. Compared with other films and the control (uncovered sausages), CFMB films delay pH reduction. Moreover, this film presents the lower lipid oxidation level (0.10 malonaldehyde mg/sample kg). Thus, chitosan of B. magna could be a good alternative as packaging material for meat products with high-fat content.     

人体外骨骼控制器硬件设计

为了适应外骨骼机器人的发展需求,设计了一款可以实现外骨骼控制的控制器,该控制器采用以PowerPC芯片为核心,FPGA芯片为辅的硬件设计,文中详细说明了各个模块的设计思想及外围接口电路的设计,由于PowerPC芯片较高的内部集成了多种功能,以及在平台中加入了以FPGA来集中控制各个接口,因此可以实现多个传感器接口信号采集和控制,并使用实时操作系统对各个传感器信号处理和控制。该控制器具有运算速度快,扩展方便,可靠性较高的特点。     

基于支持向量机的外骨骼机器人灵敏度放大控制

为了准确控制外骨骼机器人跟随人体运动,需要建立其动态、精确的数学模型;人体下肢外骨骼是一个多自由度、强耦合以及非线性的多连杆系统,难以建立准确的运动学和动力学模型;文章使用三维运动捕捉与空间定位系统,获取实际人体运动参数(运动学与动力学),应用支持向量机(SVM)学习人体下肢外骨骼的数学模型;基于该模型构造基于支持向量机模型的灵敏度放大控制方法;文章使用MATLAB和LIBSVM建立外骨骼下肢机器人的数学模型,并进行仿真分析;仿真结果表明基于SVM的模型学习方法,能够准确计算出人体下肢外骨骼的动力学模型,并简化建模过程;基于SVM的灵敏度放大控制,能够有效计算出人体下肢外骨骼各关节(髋关节、膝关节、踝关节)的输出力矩,并控制外骨骼机器人跟随人体运动。     

下肢外骨骼机器人控制的脑电感知方法研究

将外骨骼机器人技术与BCI系统结合起来,使人体具有了外骨骼机器人的一系列优良特性,同时使外骨骼机器人具备了人体的智能。首先,对外骨骼机器人技术与BCI技术的融合进行了可行性分析,说明了该方法的可行性。其次,通过实验采集了六种想象运动的脑电信号,选取了C3、C4通道的脑电信号,并对其进行了去噪处理。然后,对经过预处理的六种想象运动的脑电信号通过小波变换进行了分解,提取了包括小波分解系数和能量系数的脑电信号小波特征。最后,针对所提取的小波特征,采用了最小二乘支持向量机对这六种想象运动模式进行分类处理。