基于PC／104与单片机的仿人机器人控制系统设计

为了简化仿人机器人控制系统结构,增强机器人系统的功能.采用PC/104嵌入式系统作为仿人机器的主控计算机,完成图像处理,做出控制决策,计算并生成运动序列.关节控制器选用C8051F310单片机,采用串口与主控计算机通信,接收来自主控计算机的运动序列指令,产生PWM波,经过放大电路,实现21路电机的控制.经过实验,得到图像采集分析结果和仿人机器人稳态步行.实验表明,这种控制系统能够实现仿人机器人的控制.     

基于有限状态机的欠驱动机器人动态步行

欠驱动步行机器人动态步行是仿人机器人领域研究的热点问题,源于不依赖大力矩,复杂的反馈系统及上层的动态平衡控制策略。本文以吉林大学田彦涛教授欠课题组所研制的PADW-JLU II型机器人被控对象,利用有限机状态理论实现了该机器人的有效动态步行。     

基于倒立摆模型的仿人机器人预观控制研究

针对仿人机器人的步态行走存在不稳定和目前倒立摆模型的预观控制存在ZMP(Zero Moment Poin)跟踪精度不足的问题,文中在倒立摆模型上结合预观控制理论,对算法进行改进,并采用机器人的七连杆模型的ZMP计算结果作为预观控制的参考输入,利用实际的ZMP和目标的ZMP之间的误差量,对倒立摆模型进行补偿,规划机器人的质心轨迹,从而使倒立摆补偿ZMP预观控制模型拥有更好的ZMP跟踪效果。通过MATLAB和Adams机械动力学仿真软件进行联合仿真验证了:改进预观控制和ZMP补偿优化方法对倒立摆模型改进的有效性,并且提升了仿人机器人在行走过程中的稳定裕度。     

双足机器人RCG姿态控制算法的研究

稳定步行是仿人双足机器人开展实际作业的基础,也是研究的难点和热点.为了提高对仿人机器人步行失稳的响应速率和控制准确性,克服利用陀螺仪进行姿态测量及控制无法完整表述机器人运动状态,从而造成控制滞后的缺点.本文提出了RCG姿态控制算法,在以角速度和角度作为控制参量的模型基础上,引入机器人运动过程中的加速度作为姿态判断和调整的影响因子,实现对机器人行走过程的反馈控制,提高了双足机器人对失稳状态的响应速率和响应的准确性.通过对自主搭建的机器人样机进行测试,结果表明：当双足机器人步行失稳时,RCG姿态控制算法比以角速度和角度作为参量的控制算法能够更快速、准确的修正姿态偏差,保持姿态稳定.     

卫星刚性载荷体在轨对称摆扫特性分析

为实现卫星摆扫成像,降低载荷体摆动过程中对卫星姿态的影响,提出两个相同载荷体对称摆动的方案,并规划给定角度范围内的摆动规律,使载荷体在滚动轴和俯仰轴分别具有0.6()/s、6 ()/s的角速度,通过对两载荷体摆动特性及动力学、运动学特性的分析,提出以反作用飞轮对卫星偏航轴剩余力矩进行补偿控制的方法。以某卫星示例进行仿真分析,结果表明:两载荷体对称摆动过程中滚动轴和俯仰轴的合成力矩和角动量对卫星姿态无影响,而偏航轴存在周期性变化的力矩,采用0.2 Nm的飞轮进行动量补偿后得到卫星姿态指向精度和姿态稳定度可以控制在0.032、0.006()/s以内,能够实现较高精度的对地面区域摆扫成像。说明以两载荷体对称摆动的方案实现卫星摆扫成像并满足成像需求,在设计理念上是可行的。     

基于电磁感应的力矩发生装置研究

为解决独轮机器人、导弹、卫星及航天器等欠驱动系统的欠驱动难题,本文提出一种基于电磁感应的力矩发生装置.该装置是在经典电磁学理论支持下的研究成果,文中详述了装置的原理和具体设计的技术方案,并通过实验进行验证.本文提出的力矩发生装置的显著优势是所提供的力矩大小正比于速度项,方便用伺服电机进行精确控制,而且具有节能、无噪声的优点.在独轮机器人侧向和偏航控制中良好表现,进一步表明本文提出的力矩发生装置是实用和有效的.     

小型仿人机器人的设计及步态规划

针对现有仿人形机器人造价高的缺点,设计一款低成本的小型双足机器人研究平台.根据人类步行过程及人体生理结构.依据模糊控制与专家控制相结合的理论提出一种简单的双足机器人模型.并根据仿生学原理确定机器人的自由度配置及各关节的比例尺寸.然后,利用目前通用的行为规划软件对双足机器人步态规划进行仿真.并在平坦地面上进行相应行走试验.实验证明.根据人行走模式对机器人进行步态规划的算法稳定可行.为机器人的教学和科研提供了良好的实验平台.     

基于能量补偿的时域干扰抵消改善方法

针对时域干扰抵消方法产生的波束畸变和探测盲区问题，提出一种基于能量补偿的时域干扰抵消改善方法.该方法首先根据数据处理带宽和衰减曲线构造能量补偿因子；然后利用时域干扰抵消方法对线列阵拾取数据进行处理，得到相应波束；最后采用能量补偿因子对干扰抵消输出波束进行优化，可以减小波束畸变和探测盲区，达到预期的干扰抵消效果和探测效果.数值仿真和数据处理均表明，本文方法通过构造能量补偿因子改善了时域干扰抵消方法，降低了时域干扰抵消方法形成的"宽凹"或"凸"字型波束对目标探测性能的影响，实现了波束校正，减小了探测盲区，对原衰减区间内的目标实现了有效探测.从根本上解决了时域干扰抵消方法产生的波束畸变和探测盲区问题.     

一种上肢康复机器人的力矩控制系统设计

针对目前上肢康复机器人的输出力矩控制不便的问题,设计了一种基于磁粉离合器的力矩控制系统,并给出了相应的驱动电路。磁粉离合器能根据驱动电路的驱动电流输出相应的传递力矩,进而可以控制上肢康复机器人的输出力矩。经应用表明,该系统控制简便、安全性高,符合不同康复训练模式下对输出力矩的要求,为实时控制康复机器人的输出力矩提供了可行性验证。     

缓冲式运动中的腿部受力分析模型

针对缓冲式运动中的腿部受力分析建模难度较大,受力定量评估精度不高的问题,提出限定初始状态下误差跟踪的缓冲式运动中的腿部受力分析模型。该模型对缓冲式运动中的腿部各个关节驱动作用力矩进行受力行为控制约束参量分析,在限定初始状态下进行受力参量估计的误差跟踪,实现腿部受力动力学控制和关节驱动力矩计算。仿真结果表明,采用该模型进行缓冲式运动中的腿部受力分析,对受力行为的控制精度高,对腿部受力参量的估计误差小,促进对人体运动学的科学定量评估和分析。     

Optimum contouring of industrial robot arms under assigned velocityand torque constraints

Presents a general solution to the contouring problem of industrial robot arms, under the constraints of assigned Cartesian velocity and joint torque/acceleration. The proposed solution is an off-line trajectory generation algorithm and, therefore, it possesses significant industrial implications, as no hardware changes are needed for its implementation. According to the proposed method, the maximum utility of joint torque/acceleration is guaranteed to be bound to the assigned velocity constraint. In the proposed method, a realizable trajectory is generated from the objective trajectory and its delay dynamics are compensated for by using a forward compensator. The proposed method has been experimented with using a Performer MK-3s (PMK-3s) industrial robot arm, and optimum contouring has been realized     

Direct yaw moment control actuated through electric drivetrains and friction brakes: Theoretical design and experimental assessment

A significant challenge in electric vehicles with multiple motors is how to control the individual drivetrains in order to achieve measurable benefits in terms of vehicle cornering response, compared to conventional stability control systems actuating the friction brakes. This paper presents a direct yaw moment controller based on the combination of feedforward and feedback contributions for continuous yaw rate control. When the estimated sideslip exceeds a pre-defined threshold, a sideslip-based yaw moment contribution is activated. All yaw moment contributions are entirely tunable through model-based approaches, for reduced vehicle testing time. The purpose of the controller is to continuously modify the vehicle understeer characteristic in quasi-static conditions and increase yaw and sideslip damping during transients. Skid-pad, step-steer and sweep steer tests are carried out with a front-wheel-drive fully electric vehicle demonstrator with two independent drivetrains. The experimental test results of the electric motor-based actuation of the direct yaw moment controller are compared with those deriving from the friction brake-based actuation of the same algorithm, which is a major contribution of this paper. The novel results show that continuous direct yaw moment control allows significant “on-demand” changes of the vehicle response in cornering conditions and to enhance active vehicle safety during extreme driving maneuvers.     

Synthesis of dynamic motions for robotic manipulators with geometric path constraints

This paper presents a new method to plan minimum cost movements for non-redundant robotic manipulators along prescribed geometric paths while tacking into account various kinodynamic constraints. The problem consists of defining the best way to follow a prescribed geometric path under several constraints, such as limitations on joint torque, jerk, acceleration or velocity, while minimizing an objective function (time transfer, mean average of joint torques, etc.). It is formulated as a non-linear optimization problem and can be then treated by any adequate mathematical optimization method. Numerical examples using genetic algorithms are presented to illustrate the effectiveness of the proposed approach.     

基于模糊滑模控制的车辆稳定性研究

针对车辆在转弯或变道引起的车辆稳定性控制问题,建立了用于稳定性控制的3自由度非线性动力学模型。文中将车辆横摆角速度、质心侧偏角作为主要控制变量。基于模糊滑模控制理论,采用直接横摆力矩控制方法控制横摆角速度和质心侧偏角,其中考虑到质心侧偏角难以通过传感器测量,设计了基于递归最小二乘法的质心侧偏角估计方法。同时,在基于Matlab与ADMAS联合调试的环境下进行了仿真分析,仿真结果表明该控制器能有效地使横摆角速度和质心侧偏角跟踪其期望值,使汽车保持在安全稳定的范围内。     

基于非正交多址接入的网络切片联合用户关联和功率分配算法

为了满足网络切片多样化需求,实现无线虚拟资源的动态分配,该文提出在C-RAN架构中基于非正交多址接入的联合用户关联和功率资源分配算法。首先,该算法考虑在不完美信道条件下,以切片和用户最小速率需求及时延QoS要求、系统中断概率、前传容量为约束,建立在C-RAN场景中最大化长时平均网络切片总吞吐量的联合用户关联和功率分配模型。其次,将概率混合优化问题转换为非概率优化问题,并利用Lyapunov优化理论设计一种基于当前时隙的联合用户调度和功率分配的算法。最后采用贪婪算法求得用户关联问题次优解;基于用户关联的策略,将功率分配的问题利用连续凸逼近方法将其转换为凸优化问题并采用拉格朗日对偶分解方法获得功率分配策略。仿真结果表明,该算法能满足各网络切片和用户需求的同时有效提升系统时间平均切片总吞吐量。     

基于补偿式CSI的分布式跨层联合资源分配算法

为消除过时信道状态信息(CSI)对分布式无线多跳网络环境下跨层资源分配效率的影响,提高跨层联合资源分配的准确性,基于信道相关性提出了一种补偿式跨层联合资源分配算法。利用瞬时和过时信道状态信息之间的条件概率密度函数,基于瑞利衰落信道模型求得信噪比(SINR) 模型下条件容量的闭式解。为补偿部分网络性能的损失,提出了一种考虑过时信道状态信息的联合拥塞控制、信道分配和功率控制的算法,在此过程中网络被建模成一个NUM 问题,可变的链路数据率和功率等资源限制作为约束条件。运用拉格朗日对偶分解技术,NUM问题被分布式求解。实验对比分析表明：在确保较低复杂度的前提下,该算法有效改善了分布式多跳网络资源分配的合理性,使其网络总体效用得到提升,降低了能耗。     

基于预测控制方法的UAV视觉编队飞行控制律设计

传统的无人飞行器(UAV)视觉编队控制律考虑约束的能力不足,制约了其工程实际应用。针对不足,基于预测控制方法设计了一种能够显式考虑约束的视觉编队控制律,该控制律通过滚动求解有限时域优化问题得到跟随飞行器(follower)的控制输入。利用相对距离变化率和视线方位角变化率预测值与实测值的偏差信息,提出了领航飞行器(leader)加速度的在线估计算法。仿真结果表明,所设计的编队控制律能够控制follower飞行器快速跟随leader飞行器形成期望的编队,所提出的leader飞行器加速度估计方法可行,具有较小的估计误差。     

Direct Yaw-Moment Control of an In-Wheel-Motored Electric Vehicle Based on Body Slip Angle Fuzzy Observer

A stabilizing observer-based control algorithm for an in-wheel-motored vehicle is proposed, which generates direct yaw moment to compensate for the state deviations. The control scheme is based on a fuzzy rule-based body slip angle (beta) observer. In the design strategy of the fuzzy observer, the vehicle dynamics is represented by Takagi-Sugeno-like fuzzy models. Initially, local equivalent vehicle models are built using the linear approximations of vehicle dynamics for low and high lateral acceleration operating regimes, respectively. The optimal beta observer is then designed for each local model using Kalman filter theory. Finally, local observers are combined to form the overall control system by using fuzzy rules. These fuzzy rules represent the qualitative relationships among the variables associated with the nonlinear and uncertain nature of vehicle dynamics, such as tire force saturation and the influence of road adherence. An adaptation mechanism for the fuzzy membership functions has been incorporated to improve the accuracy and performance of the system. The effectiveness of this design approach has been demonstrated in simulations and in a real-time experimental setting.     

Modular integrated longitudinal and lateral vehicle stability control for electric vehicles

In this paper, the problem of integrated longitudinal and lateral vehicle stability control is addressed using a modular optimal control structure. The optimization process of the high level model predictive control (MPC) controller determines required longitudinal force and yaw moment adjustments to minimize the error between vehicle longitudinal and lateral vehicle stability dynamic states with respect to the target courses. The low level controller is designed to optimally regulate torque at each wheel based on the control inputs of the high level controller, and distribute required torque between the wheels via actuation system. The actuation system that is utilized to implement the proposed control structure functions based on all-wheel drive technology that can provide active control of both traction and yaw moment control with differential torque. The multi-layered structure of the control system allows modularity in design. The performance of the control structure is investigated by conducting experimental tests. The experimental tests have been performed on an electric Chevrolet Equinox vehicle equipped with four independent motors. The results show that the integration of the vehicle longitudinal and lateral dynamics preserves vehicle stability in a planar motion and improves the vehicle dynamic response, especially in challenging driving maneuvers.     

MPC-based yaw stability control in in-wheel-motored EV via active front steering and motor torque distribution

This paper focuses on yaw stability control of in-wheel-motored electric vehicle (EV), and a model predictive controller is designed based on holistic control structure via active front steering and motor torque distribution. By designing a suitable reference model, the controller stabilizes a vehicle along the desired states while rejecting skid and fulfilling its physical constraints, so this is described as a constrained tracking problem. To solve this, the holistic control scheme is built to simplify the hierarchical structure of the controller and directly optimize the control inputs of system. Based on holistic control structure and MPC method, an objective function with constraints is designed over a receding horizon to meet the control requirements. Finally, the proposed nonlinear model predictive controller is evaluated on eight degrees of freedom (8DOF) EV model offline simulation platform. Simulation results of different road maneuver on slippery surfaces show the benefits of the control methodology used.