凸轮轮廓整数向径角的计算

以LT型剑杆织机的开口凸轮为例 ,在凸轮轮廓曲线极坐标方程基础上 ,利用解一元非线性方程———区间二分法 ,对凸轮轮廓整数向径角的计算进行了研究和讨论     

偏心圆凸轮从动件运动和动力分析

对常用的偏心圆凸轮从动件进行运动和动力分析,并与其它从动件常用运动规律进行比较,推荐其应用范围及基本参数的选取范围。     

Power‐efficient analog design based on the class AB super source follower

A class AB version of the conventional super source follower (SSF) is described. The circuit greatly increases slew rate (SR) and current efficiency, maintaining the low distortion and low output resistance of the SSF. Class AB operation is achieved without extra power dissipation or supply requirements, and without bandwidth or noise degradation. The circuit can advantageously replace the SSF in a wide variety of analog systems, opening a new research line in analog design. To illustrate the widespread application of this cell, a class AB differential unity‐gain buffer, a class AB differential current mirror and two class AB differential transconductors are designed, fabricated in a 0.5µm CMOS technology and tested. Measurement results using a dual supply of ±1.65V show that the proposed class AB version of the SSF improves SR by a factor 21.5 and increases bandwidth by 10%, keeping noise level, input range, power consumption, and supply requirements unaltered. The fabricated class AB current mirror features a THD at 100 kHz of ? 62dB for signal currents 20 times larger than the bias current. The fabricated transconductors feature an IM3 at 1 MHz of ? 56.6dB for output currents more than 13 times larger than the bias currents. Copyright © 2011 John Wiley & Sons, Ltd.     

串行低速/全速接收器电路

设计用于USB Hub的接收器电路。该电路应用两级差动放大增加电路增益,利用源极跟随器作为电压缓冲器以减少信号电平损失。电路经过CSMC0．6umN阱CMOS工艺设计验证,完全符合USB1．1的协议规范。该设计已用于USB Hub芯片中。     

CMOS轨到轨电压跟随器的设计及优化

电压跟随器的电压放大倍数总是小于且趋近于1,它具有低输出阻抗、高输入阻抗的特点.也就是说在理想的情况下,从前级电路看去电压跟随器相当于断路,从后级电路看去电压跟随器又相当于一个恒压源.在具体电路中,电压跟随器一般做缓冲级和隔离级,并起着前后级阻抗匹配的作用.文中提出一种AB类高性能CMOS轨到轨电压跟随器,电路是以AB类对称式电压跟随器为基础设计的.     

对摆动从动件外啮合盘形凸轮机构压力角计算公式的讨论

本文讨论了摆动从动件盘形凸轮机构压力角的计算公式。并对压力角公式加以补充。     

Adaptive formation control of autonomous underwater vehicles with model uncertainties

This paper investigates the formation control problem of underactuated autonomous underwater vehicles (AUVs). What makes this problem different and challenging is that, in the AUV model, the mass and damping matrices are not diagonal with nonzero off‐diagonal terms and unknown hydrodynamic damping terms. To address the effect of nonzero off‐diagonal terms, we introduce a coordinate transformation, while the unknown hydrodynamic damping terms are approximated adaptively by a neural network. Then, a leader‐follower control strategy is presented, where each follower needs to track a virtual vehicle. This strategy translates the formation control problem into a set of position (including heading) tracking problems for the following AUVs. The position and heading tracking controller is designed based on Lyapunov direct method and backstepping technique, taking into account the effect of the nonzero off‐diagonal terms in the mass matrix and the unknown hydrodynamic damping terms. Simulations are given to demonstrate the effectiveness of the control method proposed.     

Distributed observer‐based leader‐follower attitude consensus control for multiple rigid bodies using rotation matrices

This paper addresses the distributed observer‐based leader‐follower attitude consensus control problem for multiple rigid bodies. An intrinsic distributed observer is proposed for each follower to estimate the leader's trajectory, which is only available to a subset of followers. The proposed observer can guarantee that the estimated attitude evolves on rotation matrices all the time, and it provides us with a simple way to design the attitude consensus control law. The dynamics of rigid bodies and distributed observer are both modeled directly on rotation matrices, so that the singularity and ambiguity can be avoided. Furthermore, adopting the idea of disturbance observer on vector space, a gyro bias observer on the rotation matrices is proposed. Based on the distributed observer, three types of attitude consensus control law are proposed, which are respectively on the basis of full‐state, biased angular velocity, and external disturbance combined with biased angular velocity. Finally, the SimMechanics experiments are provided to illustrate effectiveness of the proposed theoretical results.     

Controllability of heterogeneous multi-agent systems under directed and weighted topology

This paper considers the controllability problem for both continuous- and discrete-time linear heterogeneous multi-agent systems with directed and weighted communication topology. First, two kinds of neighbour-based control protocols based on the distributed protocol of first-order and second-order multi-agent systems are proposed, under which it is shown that a heterogeneous multi-agent system is controllable if the underlying communication topology is controllable. Then, under special leader selection, the result shows that the controllability of a heterogeneous multi-agent system is solely decided by its communication topology graph. Furthermore, some necessary and/or sufficient conditions are derived for controllability of communication topology from algebraic and graphical perspectives. Finally, simulation examples are presented to demonstrate the effectiveness of the theoretical results.     

Coordination of discrete‐time multi‐agent systems via relative output feedback

This paper investigates the joint effects of agent dynamic and network topology on the consensusability of linear discrete‐time multi‐agent systems via relative output feedback. An observer‐based distributed control protocol is proposed. A necessary and sufficient condition for consensusability under this control protocol is given, which explicitly reveals how the intrinsic entropy rate of the agent dynamic and the eigenratio of the undirected communication graph affect consensusability. As a special case, multi‐agent systems with discrete‐time double integrator dynamics are discussed where a simple control protocol directly using two‐step relative position feedback is provided to reach a consensus. Finally, the result is extended to solve the formation and formation‐based tracking problems. The theoretical results are illustrated by simulations. Copyright © 2010 John Wiley & Sons, Ltd.