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81.
为了实现移动机器人的高精度轨迹跟踪控制, 设计了一种基于扩张状态观测器的扰动抑制方法和相应的
实验验证平台. 首先, 考虑到不确定扰动如车轮纵向和侧向滑动对移动机器人系统控制性能的影响, 建立了受扰下
的运动学模型; 然后, 基于扩张后的运动学模型设计了扩张状态观测器来估计系统扰动; 接着, 利用扰动估计构建
了线性自抗扰控制器, 并利用Lyapunov函数证明了闭环系统的稳定性; 同时, 基于MATLAB/Simulink软件和微控制
器搭建了所推荐控制算法的实验验证平台. 最后, 仿真和实验结果都验证了所提出控制方法的有效性. 相似文献
82.
本文针对飞行器姿态跟踪控制问题, 考虑系统的内部模型不确定性和外界扰动, 设计了使跟踪误差一致最终有界的控制器. 以四元数为姿态参数, 建立系统的非线性误差模型; 将控制系统分为内环观测器和外环控制器分别设计, 其中, 线性扩张状态观测器作为系统内环将实际系统补偿为标称模型, 而外环非线性控制器则用于镇定非线性标称系统. 最后, 利用Lyapunov理论得到了一致最终有界的稳定性结论, 并基于频域理论, 分析了线性扩张状态观测器阶次对系统性能的影响. 姿态跟踪实验表明, 本文设计的控制系统能够有效实现飞行器的姿态跟踪控制. 相似文献
83.
A new look at ESO and BESO optimization methods 总被引:1,自引:1,他引:0
The “hard-kill” optimization methods such as evolutionary structural optimization (ESO) and bidirectional evolutionary structural
optimization (BESO) may result in a nonoptimal design (Zhou and Rozvany in Struct Multidisc Optim 21:80–83, 2001) when these
methods are implemented and used inadequately. This note further examines this important problem and shows that failure of
ESO may occur when a prescribed boundary support is broken for a statically indeterminate structure. When a boundary support
is broken, the structural system could be completely changed from the one originally defined in the initial design and even
BESO would not be able to rectify the nonoptimal design. To avoid this problem, it is imperative that the prescribed boundary
conditions for the structure be checked and maintained at each iteration during the optimization process. Several simple procedures
for solving this problem are suggested. The benchmark problem proposed by Zhou and Rozvany (Struct Multidisc Optim 21:80–83,
2001) is revisited, and it is shown that the highly nonoptimal design can be easily avoided. 相似文献
84.
采用直驱式伺服控制的新型电液舵机系统具有非线性程度高、系统响应慢、易受外界负载扰动等特点,传统的PID控制器无法抵抗外界干扰,对大工况变化系统控制效果差。为克服传统PID控制器的缺点,安排了过渡过程,调节系统的响应过程以降低启停过程的动态冲击;设计了扩张状态观测器,估计补偿系统受到的水动力负载扰动;进一步通过非线性控制规律组合,增加了系统的响应速度。基于设计的自抗扰控制器,采用了MATLAB和AMESim联合仿真研究。与传统的PID控制器对比:运用自抗扰控制的电液舵机,启停过程更加平滑;控制特性不变的情况下系统抗干扰能力得到进一步增强。 相似文献
85.
The paper considers the tracking problem for a class of uncertain linear time invariant (LTI) systems with both uncertain parameters and external disturbances. The active disturbance rejection tracking controller is designed and the resulting closed-loop system׳s characteristics are comprehensively studied. In the time-domain, it is proven that the output of closed-loop system can approach its ideal trajectory in the transient process against different kinds of uncertainties by tuning the bandwidth of extended state observer (ESO). In the frequency-domain, different kinds of parameters׳ influences on the phase margin and the crossover frequency of the resulting control system are illuminated. Finally, the effectiveness and robustness of the controller are verified through the actuator position control system with uncertain parameters and load disturbances in the simulations. 相似文献
86.
Di-hydroxylated soybean oil (DSO) polyols with three different hydroxyl values (OHV) of 160, 240, and 285 mg KOH/g were synthesized from epoxidized soybean oils (ESO) by oxirane cleavage with water catalyzed by perchloric acid. The DSO were clear, viscous liquids at room temperature. The structure and physical properties of DSO were characterized using titration methods, Fourier-transform infrared spectroscopy (FTIR), gel permeation chromatography, rheometer, differential scanning calorimetry, and thermogravimetric analysis. The number average molecular weight of DSO160, DSO240, and DSO285 were 1,412, 1,781, and 1,899 g/mol, respectively, indicating that oligomerization occurred during DSO synthesis, which was further confirmed by FTIR. All DSO polyols exhibited non-Newtonian, shear thinning behavior. DSO with higher OHV were more viscous than those with lower OHV. All DSO were thermally stable up to 380 °C. These three DSO were formulated into pressure-sensitive adhesives (PSA) by copolymerizing with ESO using UV curing. The peel adhesion strength of the PSA was significantly affected by the OHV of DSO and DSO content. Maximal PSA adhesion strength of 4.6 N/inch was obtained with DSO285 and a DSO/ESO weight ratio of 0.75. 相似文献
87.
88.
89.
René Quispe Rodríguez Renato Picelli Paulo Sollero Renato Pavanello 《Journal of Adhesion Science and Technology》2014,28(14-15):1451-1466
This work presents an application of the evolutionary structural optimization (ESO) method to optimize two of the most common bonded joints – the single lap joint and the double lap joint. The ESO method was used to shape the adherends contour to reduce peak stresses at the overlap ends. The shape optimization was performed under a von Mises rejection criterion. The von Mises stress was evaluated using the finite element model for both types of joints. It is proposed here to utilize a honeycomb-like mesh using hexagonal elements to minimize stress concentration problem. Additionally, the use of a honeycomb mesh in the ESO method led to a smoother adherend contour. Numerical results show how the stress distributions for both shear and peel stresses are improved after the application of this optimization method. 相似文献
90.
自抗扰控制技术研究及实际应用过程中,由于参数较多,且被控对象不同,参数整定的方向和大小不确定,使得参数整定变得困难。通过实际仿真分析,给出了自抗扰控制器参数整定的一些规律,对自抗扰控制器的实际应用具有较大的意义。 相似文献