六自由度并联机器人分散鲁棒非线性控制

针对六自由度并联机器人动力学特点,提出了一种新型分散鲁棒非线性控制方法.与传统PD控制策略和已有分散鲁棒非线性控制方法相比,由于控制律中增加了广义误差的小数幂项,改进后的方法除保持原方法的优点外,还具有较强的终端收敛能力,能够保证跟踪误差以更快的速度全局一致收敛到一个更小的剩余集.通过选择合适的控制器参数,可使剩余集趋于0.运用Lyapunov方法分析了系统稳定性,给出了系统稳定性条件.最后,仿真结果验证了该方法的有效性.     

自适应神经模糊推理结合PID控制的并联机器人控制方法

针对6自由度液压驱动并联机器人的精确控制问题,提出一种结合自适应神经模糊推理系统(ANFIS)和比例积分微分(PID)控制的机器人控制方法。首先,利用浮动坐标系描述法(FFRF)来模拟机器人柔性组件,并构建并联机器人的拉格朗日动力学模型。然后,根据模糊推理中的模糊规则来自适应调整PID控制器参数。最后,利用神经自适应学习算法使模糊逻辑能计算隶属度函数参数,从而使模糊推理系统能追踪给定的输入和输出数据。将该控制器与传统PID控制器、模糊PID控制器进行比较,结果表明,ANFIS自整定PID控制器大大减小了末端器位移误差,能很好的控制并联机器人末端机械手的运动。     

输送用双并联机器人鲁棒同步滑模控制方法

为同时解决输送用多电机驱动双并联机器人的同步协调性问题和受关节非线性摩擦、动力学参数建模误差及外界干扰等不确定因素影响的鲁棒性问题,提出一种双并联机器人复合误差鲁棒同步滑模控制方法.建立含集总扰动项的双并联机器人动力学模型,通过引入非线性扰动观测器,设计一种基于复合误差的鲁棒同步滑模控制算法,以选取较小的同步滑模控制切...     

并联机器人的鲁棒自适应控制

本文针对含有不确定性的液压并联机器人，提出了一种鲁棒自适应控制器，该控制器能够克服参数变化和负载扰动的不良影响，保证系统的鲁棒全局渐近稳定性的良好的踊跃动态性能，计算机仿真结果证明了该控制方案的有效性。     

6—DOF液压并联机器人运动轨迹自适应控制

本文为6－DOF液压并联机器人提出了一种从参考模型取状态设计的运动轨迹MARCS，该系统不仅解决了机器人二阶以上运动状态难于测量的控制，而且增加了系统抗噪声干扰的能力。     

并联机器人轨迹跟踪变结构控制的研究

本文根据并联机器人控制的特点，将离散变结构理论应用于并联机器人的轨迹控制，引进了离散趋近律的概念，给出了实用的离散变结构控制算法，仿真表明，该方法对并联机器人轨迹踪具有良好的控制效果。     

并联机器人力控制算法实时并行处理

对并联机器人力控制算法基于并行结构的计算进行了研究，设计了并行处理双机系统结构。采用文中的处理方法大大提高了并联机器人力控制算法的处理速度，保证了实时力控制，进而改善并联机器人的控制质量与性能。     

基于改进型BP网络的并联机器人自适应力控制

并联机器人力控制是并联机器人研究的一个热点和难点,引起了许多学者的关注,并取得了一定的成果。多数使用了传统的力控制研究方法。该文中,作者将神经网络引入并联机器人的力控制中,并介绍了一种改进型BP神经网络,以及其学习算法和网络的训练过程,并结合实际并联机器人6-SPS并联机器人,设计出基于改进型BP神经网络的并联机器人自适应力控制器,并进行了仿真和实验研究,通过研究表明所设计的控制器是可行和有效的。     

高精度轨迹跟踪的6-PRRS并联机器人自抗扰控制研究

针对6-PRRS并联机器人控制系统的非线性、耦合等特性,采用分散控制策略。在关节空间设计强鲁棒性的自抗扰控制器对其进行控制．该自抗扰控制器由非线性跟踪微分器、扩张状态观测器、非线性PD和扰动补偿4部分组成．具有模型补偿功能的扩张状态观测器可以获得系统的状态估计和未知外扰的实时作用量,使系统性能得到有效补偿．该控制器以离散的形式进行设计,易于工程实现．仿真结果证明了所提出的控制策略具有强鲁棒性,跟踪性能良好．     

6-PRRS并联机器人的小脑模型神经网络控制

设计了小脑神经网络控制器.采用分散控制策略利用小脑神经网络来消除并联机器人控制系统非线性、耦合的影响及学习系统的不确定信息,作为前馈补偿使系统跟踪误差快速收敛;并采用PID作为反馈控制,保证系统的稳定性,从而实现6-PRRS并联机器人的快速、稳定轨迹跟踪.     

Robust nonlinear control of a planar 2-DOF parallel manipulator with redundant actuation

A new robust nonlinear controller is presented and applied to a planar 2-DOF parallel manipulator with redundant actuation. The robust nonlinear controller is designed by combining the nonlinear PD (NPD) control with the robust dynamics compensation. The NPD control is used to eliminate the trajectory disturbances, unmodeled dynamics and nonlinear friction, and the robust control is used to restrain the model uncertainties of the parallel manipulator. The proposed controller is proven to guarantee the uniform ultimate boundedness of the closed-loop system by the Lyapunov theory. The trajectory tracking experiment with the robust nonlinear controller is implemented on an actual planar 2-DOF parallel manipulator with redundant actuation. The experimental results are compared with the augmented PD (APD) controller, and the proposed controller shows much better trajectory tracking accuracy.     

Adaptive robust posture control of a parallel manipulator driven by pneumatic muscles

Rather severe parametric uncertainties and uncertain nonlinearities exist in the dynamic modeling of a parallel manipulator driven by pneumatic muscles. Those uncertainties not only come from the time-varying friction forces and the static force modeling errors of pneumatic muscles but also from the inherent complex nonlinearities and unknown disturbances of the parallel manipulator. In this paper, a discontinuous projection-based adaptive robust control strategy is adopted to compensate for both the parametric uncertainties and uncertain nonlinearities of a three-pneumatic-muscles-driven parallel manipulator to achieve precise posture trajectory tracking control. The resulting controller effectively handles the effects of various parameter variations and the hard-to-model nonlinearities such as the friction forces of the pneumatic muscles. Simulation and experimental results are obtained to illustrate the effectiveness of the proposed adaptive robust controller.     

基于SIMULINK的非线性优化PID控制

提出了利用MATLAB优化控制工具箱与优化函数相结合对非线性系统PID控制器进行优化设计的方法,同时建立了基于MATLAB/SIMULINK的非线性系统仿真图.通过仿真试验,验证了该参数优化设计方法不仅方便快捷,而且使系统具有较好的控制精度和稳定性,可使系统的性能有所提高.     

基于模糊PID的悬吊式机械臂重力补偿控制系统设计

针对悬吊式机械臂在工作过程中受起吊荷载的影响而产生的重心不稳现象,在模糊PID控制算法的支持下,进行悬吊式机械臂重力补偿控制系统设计研究。硬件方面,改装主控制器、传感器和通信模块,加设重力补偿装置及驱动电机设备。在此基础上完成软件设计,根据机械臂的组成结构以及工作原理,构建悬吊式机械臂数学模型。在该模型下,检测悬吊式机械臂实时位姿,针对不同位姿建立相应的重力平衡方程。计算机械臂负载力矩,利用模糊PID算法求解机械臂重力补偿控制量,实现悬吊式机械臂重力补偿控制功能。实验结果表明：与传统重力补偿控制系统相比,优化设计系统的控制误差降低了0.056kN,机械臂的稳定系数提升了0.14,即优化设计系统可提高补偿控制效果,具有一定应用价值。     

Dynamics and control of a novel 3-DOF parallel manipulator with actuation redundancy

This paper deals with the dynamics and control of a novel 3-degrees-of-freedom （DOF） parallel manipulator with actuation redundancy. According to the kinematics of the redundant manipulator, the inverse dynamic equation is formulated in the task space by using the Lagrangian formalism, and the driving force is optimized by utilizing the minimal 2-norm method. Based on the dynamic model, a synchronized sliding mode control scheme based on contour error is proposed to implement accurate motion tracking control. Additionally, an adaptive method is introduced to approximate the lumped uncertainty of the system and provide a chattering-free control. The simulation results indicate the effectiveness of the proposed approaches and demonstrate the satisfactory tracking performance compared to the conventional controller in the presence of the parameter uncertainties and un-modelled dynamics for the motion control of manipulators.     

Jerk analysis of a six-degrees-of-freedom three-legged parallel manipulator

In this work the jerk analysis of a 3-RRPS parallel manipulator to realize six degrees of freedom is approached by means of the theory of screws. The input/output equations of velocity, acceleration and jerk of the moving platform with respect to the fixed platform are obtained systematically by resorting to reciprocal-screw theory. A numerical example is included in order to show the application of the method of kinematic analysis. Furthermore, the numerical results obtained via screw theory are satisfactorily compared with simulations generated with the aid of commercially available software.     

Analytical method of PID controller design for parallel cascade control

An analytical method of PID controller design is proposed for parallel cascade control. Firstly, a general structure for parallel cascade control is proposed that takes both setpoint and load disturbance responses into account. Analytical tuning rules for the PID controllers are then derived for the general process model by employing the IMC design procedure. The proposed method offers a simple and effective way to obtain the PID controller rules for parallel cascade control system which takes into account the interaction between primary and secondary control loops. The simulation results illustrate the application of the proposed method and demonstrate its superiority compared to several alternatives.     

Design of a 3-DOF tripod electro-pneumatic parallel manipulator

The objective of the research project was to design and construct a 3DOF tripod-type electro-pneumatic parallel manipulator that could be used for pick-and-place tasks in municipal waste recycling facilities. The fundamental requirement was that the manipulator be simple and cheap to construct, operate and maintain as well as robust and resistant to damage. The forward and inverse kinematic problem as well as working space and strength analysis issues were used for construction of manipulator. The prototype was tested using different payloads and velocities to establish its positioning accuracy and repeatability. The robot behavior was controlled with a commercially available industrial controller, which was reported insufficient for point-to-point operations required during solid waste handling. Conclusions have been drawn on how to optimize the robot structure and control.     

一种新型非线性PID控制器

将非线性函数与简单的PID控制器相级联，构成一种新型的非线性PID控制器，以提高现有PID控制器的性能，新型PID控制器的设计过程十分简单，只要适当构造非线性函数，并与原PID控制器级联起来便可实现，数值仿真结果表明，所提出的PID控制器比简单的PID控制器具有更好的动静态性能。     

Trajectory tracking control of a 6-DOF hydraulic parallel robot manipulator with uncertain load disturbances

This study addresses the trajectory tracking control of a 6-DOF (degrees of freedom) hydraulic parallel robot manipulator with uncertain load disturbances. As load disturbances are the main external disturbances of the parallel robot manipulators and have a significant impact on system tracking performance, many researchers have been devoted to synthesize advanced control methods for improving the system robustness under the assumption that load disturbances are bounded. However, load disturbances are uncertain and vary in a large range in real situation happening in most hydraulic parallel robot manipulators, which is opposed to the assumption. In this paper, the load disturbances are directly measured by force sensors. Then a sliding mode control with discontinuous projection-based adaptation laws is proposed to improve the tracking performance of the parallel robot manipulator. Simulations and experiments with typical desired trajectory are presented, and the results show that good tracking performance is achieved in the presence of uncertain load disturbances.