直接驱动Xy平台零相位误差跟踪新型交叉耦合控制

针对直接驱动XY平台高精密轮廓加工中存在的电气——机械延迟、系统参数不确定性及两轴驱动系统参数不匹配以及扰动等因素影响轮廓加工精度的问题,提出了将零相位误差跟踪控制(ZPETC)与新型交叉耦合控制相结合的策略对两轴的运动进行协调控制,实现跟踪误差与轮廓误差同时减小。ZPETC作为前馈跟踪控制器,提高了快速性,克服了伺服滞后,使系统实现准确跟踪,减小了跟踪误差,进而有利于减小轮廓误差;新型交叉耦合控制作用于两轴之间,将轮廓误差作为直接被控量进行实时补偿控制,特别有效地提高了轮廓精度并简化了控制器设计。仿真和实验结果表明所设计控制系统具有较好的跟踪性和鲁棒性,进而大大提高了跟踪精度和轮廓精度。     

用于多相和正交信号产生的RF互耦振荡器原理

文章证明了以一定方式相互耦合的多个相同子系统构成的系统在一定务件下能够产生多相或正交振荡信号。根据这一理论，作为例子，给出了一个RC多相互耦振荡器，并推导出了其保持稳定振荡的务件。此外，对于四相位，即正交相位，的情况，也给出了具体的数值结果，与前面的理论分析相一致。     

Precise contour following for biaxial systems via an A-type iterative learning cross-coupled control algorithm

This paper proposes an A-type iterative learning cross-coupled control (CCC) algorithm for biaxial systems. An algebraic equation based contour error model is used as the CCC input. This model has the advantage that it is zero if and only if the real value vanishes. The iterative learning CCC is designed to make its input converge to zero. Hence, it is expected to that the contour error will converge to zero as well. After analyzing the control algorithm convergence condition in the frequency domain, the proposed method is implemented on a motion stage. Experimental results show that the algorithm perfectly follows contours as the cycles approach infinity regardless of whether tracking errors are small or large.     

A Cross-Coupled Path Precompensation Algorithm for Rapid Prototyping and Manufacturing

A cross-coupled path precompensation (CCPP) algorithm for a rapid prototyping and manufacturing (RPM) system is proposed in this paper in order to reduce the contour error resulting from the dynamic track error in the position control of the RPM system. The input of the CCPP plant is generated by a software interpolator, and the output is the compensated feedrate of the biaxial system. The precompensation amount is computed according to track errors that are estimated by mathematical models of each servo mechanism and the tangent angle at the desired point along the prespecified path. The new point acquired by the precompensation method is located in the normal direction of the original point. Simulation and experiments on the algorithm along a circular path of 200 mm in diameter are implemented. The experimental results demonstrate the advantage of the algorithm for RPM systems.     

Self-start-up fully integrated DC-DC step-up converter using body biasing technique for energy harvesting applications

An ultra-low power, self-start-up switched-capacitor Two Branch Charge Pump (TBCP) circuit for low power, low voltage, and battery-less implantable applications is proposed. In order to make feasible the low voltage operation, the proposed charge pump along with Non-Overlapped Clock generator (NOC) are designed working in sub-threshold region by using body biasing technique. A four-stage TBCP circuit is implemented with both NMOS and PMOS transistors to provide a direct load flow. This leads to a significant drop in reverse charge sharing and switching loss and accordingly improves pumping efficiency. A post-layout simulation of designed four-stage TBCP has been performed by using an auxiliary body biasing technique. Consequently, a low start-up voltage of 300 mV with a pumping efficiency of 95% for 1 pF load capacitance is achieved. The output voltage can rise up-to 1.88 V within 40 μs with 0.2% output voltage ripple in case of using 400 mV power supply. The designed circuit is implemented by 180-nm standard CMOS technology with an effective chip area of 130.5 μm × 141.8 μm while the whole circuit consumes just 3.2 μW.     

Robust guaranteed cost control for uncertain stochastic systems with multiple decision makers

The guaranteed cost control (GCC) problem for uncertain stochastic systems with N decision makers is investigated. It is noteworthy that the necessary conditions, which are determined from Karush-Kuhn-Tucker (KKT) conditions, for the existence of a guaranteed cost controller have been derived on the basis of the solutions of cross-coupled stochastic algebraic Riccati equations (CSAREs). It is shown that if CSAREs have an optimal solution, then the closed-loop system is exponentially mean square stable (EMSS) and has a cost bound. In order to simplify computations and attain a global optimum, the linear matrix inequality (LMI) technique is also considered. Finally, a numerical example for a practical megawatt-frequency control problem shows that the proposed methods can help in attaining an adequate cost bound. Furthermore, the features of these methods are characterized.     

交叉耦合自适应神经元控制器应用于抛物线轨迹加工中的研究

本文综合了自适应神经元控制器与交叉耦合控制方法的优点,引入轮廓误差的二次性能指标,设计了应用于抛物线轨迹加工的交叉耦合自适应神经元控制器。该控制器具有良好的自适应学习能力,无须对控制对象建模,结构简单,实时性好,实验证明可有效减小抛物线轮廓误差。     

交叉耦合自适应神经元控制器在双轴运动位置伺服系统中的应用

本文综合了自适应神经元控制器与交叉耦合控制方法的优点,引入轮廓误差的二次性能指标,设计了应用于双轴运动位置伺服系统中的交叉耦合自适应神经元控制器,该控制器无需对控制对象建模,具有自适应学习能力,并且结构简单,实时性好,其设计目的是有效减少轮廓加工误差,实验结果说明了控制的有效性。     

Contour error reduction for free-form contour following tasks of biaxial motion control systems

In modern machining applications, reduction of contour error is an important issue concerning multi-axis contour following tasks. One popular approach to this problem is the cross-coupled controller (CCC). By exploiting the structure of CCC, an integrated control scheme is developed in this paper and an in-depth investigation on the issue of contour error reduction is also conducted. The proposed motion control scheme consists of a feedback controller, a feedforward controller, and a modified contour error controller (CCC equipped with a real-time contour error estimator). In addition, a fuzzy logic-based feedrate regulator is proposed to further reduce the contour error. The proposed feedrate regulator is designed based on the real-time estimated contour error and the curvature of the free-form parametric curves for machining. Several experiments are conducted to evaluate the performance of the proposed approach. Experimental results demonstrate the effectiveness of the proposed approach.     

Low-dropout regulator with dual cross-coupled current mirrors

A low-dropout regulator (LDO) based on dual cross-coupled current mirrors is reported in this paper. The proposed dual cross-coupled current mirrors boost output signal current such that the loop gain of LDO is significantly enhanced, and the error amplifier in LDO retains single-pole property within the loop bandwidth of LDO. Designed in a 65-nm CMOS process and operating at a minimum of 1-V supply, the proposed LDO provides a 0.8-V output and delivers a maximum of 50 mA. The figure-of-merit of the proposed LDO is 8.9 ps.