共查询到20条相似文献,搜索用时 890 毫秒
1.
2.
考虑驱动系统动态的机械手神经网络控制及应用 总被引:2,自引:0,他引:2
针对结构和参数均未知的机械手控制问题, 提出了考虑驱动系统动态的机械手神经网络控制方法, 采用稳定的径向基(Radial basis function, RBF)神经网络辨识机械手未知动态, 而附加的鲁棒控制可以保证存在神经网络的建模误差和外部干扰时系统的稳定性和性能, 并且该方法使机械手闭环系统一致最终有界. 同时开发了基于半实物仿真技术的机械手控制系统, 最后, 将本文方法与经典的PD控制器和自适应控制器在同一机械手平台上进行了实验验证与分析, 实验结果表明该方法具有良好的控制性能. 相似文献
3.
基于改进自构形学习算法的RBF网络结构优化 总被引:2,自引:0,他引:2
RBF网络中的隐层神经元的数目直接影响着整个网络的性能和效率,因而对RBF网络的结构优化是一个非常必要的环节。本文先采用分步式训练构造初始RBF网络,然后利用改进的神经网络自构形学习算法对所构造的RBF网络的隐层进行优化,最后通过实验结果的分析与对比,验证改进的神经网络自构形学习算法对RBF网络优化的有效性。 相似文献
4.
5.
基于RBF神经网络逆系统的机械手解耦控制策略 总被引:1,自引:1,他引:0
针对机械手系统具有非线性时变、多变量、强耦合的特点,提出一种基于RBF神经网络逆系统的机械手解耦控制策略。首先证明了系统的可逆性,进一步通过神经网络在线逆辨识建立机械手的神经网络逆系统模型,并将辨识得到的逆模型作为控制器模型与机械手系统串联,构成伪线性复合系统,实现了将具有强耦合特性的多变量输入/输出机械手系统解耦成单个独立的伪线性对象。最后以两关节机械手为仿真对象进行了仿真,仿真结果验证了本方案的有效性和可行性。 相似文献
6.
机械手具有能不断重复工作和劳动的特点,由于其本身的结构刚度和接触刚度较低时,容易产生振动。为了获取良好的机械手位置控制结果,提出一种基于PLC的多自由度分拣机械手位置控制方法。分析多自由度分拣机械手的运动方式,通过Burg算法对机器人运动想象原始脑电数据滤波处理,提取和运动想象相关的频段。多自由度分拣机械手信号经过小波分解处理后获取小波系数,将其和运动想象频段两者相互对应的时域信息输入共空间模式,完成脑电信号的预处理和特征提取。将机器人运动想象任务转换为控制命令输入到PLC控制器中,使其可以驱动电机,同时利用传感器完成机械手位置控制。实验测试结果表明,所提方法控制机械手的真实轨迹跟踪与期望轨迹基本一致,跟踪轨迹的误差小,表明所提方法能够精准完成机械手的位置控制。 相似文献
7.
8.
为了提高径向基函数RBF神经网络预测模型对短时交通流的预测准确性,提出了一种基于改进人工蜂群算法优化RBF神经网络的短时交通流预测模型。利用改进人工蜂群算法确定RBF网络隐含层的中心值以及隐含层单元数,然后训练改进的人工蜂群算法RBF神经网络预测模型,并将其应用到某城市4天的短时交通流量数据的验证。将实验结果与传统RBF神经网络预测模型、BP神经网络预测模型和小波神经网络预测模型进行了比较。对比结果表明,该方法对短时交通流具有更高的预测准确性。 相似文献
9.
应用径向基函数RBF神经网络对船用污水处理装置运行状态在线监测,以提高船用污水处理装置运行状态监测与管理的效率。在分析了RBF神经网络原理的基础上,研究一种监测船用污水处理装置运行状态的三层径向基神经网络。通过实际在线监测数据的RBF神经网络监测训练和实验验证,表明RBF神经网络对运行状态的分类效果较佳,能够有效地监测船用污水处理装置的状态,并为装置维修提供科学的决策支持。 相似文献
10.
为了保证风洞试验绳牵引并联机器人(WTT–WDPR)末端执行器的位姿,提出了一种基于局部模型逼近的自适应径向基(RBF)神经网络控制.采用牛顿–欧拉法建立了飞机模型的动力学方程,并基于动态力矩平衡方程建立了驱动系统的动力学方程.采用RBF神经网络进行了局部模型的逼近设计和控制律设计,并通过构建Lyapunov函数对系统进行了稳定性分析,结果证明WTT–WDPR是趋于渐进稳定的.对WTT–WDPR进行MATLAB/Simulink仿真实验,仿真结果验证了所设计的自适应RBF神经网络控制的正确性和可行性,满足系统控制精度的要求,也为在样机上进行实际应用和技术实现奠定了理论基础. 相似文献
11.
A systematic, unified kinematic analysis for manipulator arms mounted to mobile platforms is presented. The differential kinematics for the composite system is used, along with an extended definition of manipulability, to generate a design tool for this class of systems. An example is presented in which a 3 DOF anthropomorphic manipulator is mounted on a platform powered by two independent drive wheels. Scaled manipulability ellipses are used to visualize the effect of manipulator mounting position on the overall mobility of the system. Given information about the intended tasks of the mobile manipulator, conclusions may be drawn as to the most appropriate mounting site. For the tasks which motivated this research, automated highway construction and maintenance, it was concluded that the manipulator base should be near the axles of the drive wheels and far from the centerline of the platform. © 2000 John Wiley & Sons, Inc. 相似文献
12.
Yunong Zhang Weibing Li Bolin Liao Dongsheng Guo Chen Peng 《Journal of Intelligent and Robotic Systems》2014,75(3-4):393-411
Mobile manipulator robotic systems (MMRSs) composed of a manipulator and a mobile platform are investigated in this paper. In order for the mobile manipulator robotic system (MMRS) to return to its initial state when the manipulator’s end-effector is requested to execute cyclical tasks, a quadratic program (QP) based repetitive motion planning and feedback control (RMPFC) scheme is proposed and analyzed. Such an RMPFC scheme can not only mix motion planning and reactive control, but also consider the physical limits of the robotic system. Mathematically, the efficacy of the RMPFC scheme is verified via gradient dynamics analysis. To further demonstrate the effectiveness of the RMPFC scheme, a kinematically redundant MMRS composed of a three degrees-of-freedom (DOF) planar manipulator and an omnidirectional mobile platform is designed, modeled and analyzed. Then, repetitive motion planning and feedback control for the designed omnidirectional MMRS is studied. Besides, a numerical algorithm is developed and presented to solve the QP and resolve the redundancy of the robotic system. Moreover, computer simulations are comparatively performed on such an omnidirectional MMRS, and simulation results substantiate the effectiveness, accuracy and superiority of the proposed RMPFC scheme. 相似文献
13.
Most industrial manipulators operate from a fixed base. Hence, there are no disturbances from the environment to alter the position of the end‐effector. On the other hand, manipulators that are mounted on mobile platforms are subject to disturbances emerging from unwanted motion at the base. Similarly, manipulators that perform delicate operations in space while on board in‐orbit spacecraft experience disturbances. This article describes the design and implementation of a disturbance rejection controller for a 6 degree‐of‐freedom (DOF) programable universal manipulator for assembly (PUMA) manipulator mounted on a 3‐DOF platform. A control algorithm is designed to track the desired position and attitude of the end‐effector in inertial space, subject to unknown disturbances in the platform axes. Experimental results are presented for step, sinusoidal, and random disturbances in the platform rotational axis and in the neighborhood of kinematic singularities. ©1999 John Wiley & Sons, Inc. 相似文献
14.
Franois G. Pin Kristi A. Morgansen Faithlyn A. Tulloch Charles J. Hacker Kathryn B. Gower 《野外机器人技术杂志》1996,13(11):723-736
The efficient utilization of the motion capabilities of mobile manipulators, i.e., manipulators mounted on mobile platforms, requires the resolution of the kinematically redundant system formed by the addition of the degrees of freedom (DOF) of the platform to those of the manipulator. At the velocity level, the linearized Jacobian equation for such a redundant system represents an underspecified system of algebraic equations, which can be subject to a varying set of contraints such as a non-holonomic constraint on the platform motion, obstacles in the workspace, and various limits on the joint motions. A method, which we named the Full Space Parameterization (FSP), has recently been developed to resolve such underspecified systems with constraints that may vary in time and in number during a single trajectory. In this article, we first review the principles of the FSP and give analytical solutions for constrained motion cases with a general optimization criterion for resolving the redundancy. We then focus on the solutions to (1) the problem introduced by the combined use of prismatic and revolute joints (a common occurrence in practical mobile manipulators), which makes the dimensions of the joint displacement vector components non-homogeneous, and (2) the treatment of a non-holonomic constraint on the platform motion. Sample implementations on several large-payload mobile manipulators with up to 11 DOF are discussed. Comparative trajectories involving combined motions of the platform and manipulator for problems with obstacle and joint limit constraints, and with non-holonomic contraints on the platform motions, are presented to illustrate the use and efficiency of the FSP approach in complex motion planning problems. © 1996 John Wiley & Sons, Inc. 相似文献
15.
By a mobile manipulator we mean a robotic system composed of a non-holonomic mobile platform and a holonomic manipulator fixed to the platform. A taskspace of the mobile manipulator includes positions and orientations of its end effector relative to an inertial coordinate frame. The kinematics of a mobile manipulator are represented by a driftless control system with outputs. Admissible control functions of the platform along with joint positions of the manipulator constitute the endogenous configuration space. Endogenous configurations have a meaning of controls. A map from the endogenous configuration space into the taskspace is referred to as the instantaneous kinematics of the mobile manipulator. Within this framework, the inverse kinematic problem for a mobile manipulator amounts to defining an endogenous configuration that drives the end effector to a desirable position and orientation in the taskspace. Exploiting the analogy between stationary and mobile manipulators we present in the paper a collection of regular and singular Jacobian inverse kinematics algorithms. Their performance is evaluated on the basis of intense computer simulations. 相似文献
16.
Keigo Watanabe Kazuya Sato Kiyotaka Izumi Yutaka Kunitake 《Journal of Intelligent and Robotic Systems》2000,27(1-2):3-20
This paper describes analysis and control for a holonomic omnidirectional mobile manipulator, in which the holonomic omnidirectional platform consists of three lateral orthogonal wheel assemblies and a mounted manipulator with three rotational joints is located at the center of gravity of the platform. We first introduce the kinematic model for the mobile manipulator and derive the dynamical model by using the Newton–Euler method, where a model which simultaneously takes account of features of both the manipulator and the mobile parts is given to analyze the effect of the movement of mounted manipulator on the platform. Then, the computed torque control and the resolved acceleration control methods are used to show that the holonomic omnidirectional mobile manipulator can be controlled so as to retain any end-effector position and orientation, irrespective of the direction of external applied force. The validity of the model and the effectiveness of the present mobile manipulator are proved by using several numerical simulations and 3D animations. 相似文献
17.
轮式移动机械臂的建模与仿真研究 总被引:4,自引:0,他引:4
移动机械臂系统一般由移动平台和机器臂组成,它既具有机器臂的操作灵活性,又具有移动机器人的可移动性,因此其应用范围要比单个系统宽得多。这篇文章主要研究了由非完整移动平台和完整机械臂组成的轮式移动机械臂系统的建模、跟踪控制及仿真问题。首先。利用拉格朗日动力学方程和非完整动力学罗兹方程建立了移动机械臂系统的精确数学模型;然后。利用非线性反馈将系统解耦。采用类PD控制器进行控制。在考虑了非完整约束及移动平台和机械臂的动态交互影响情况下,该控制算法保证系统同时跟踪给定的终端执行器和平台轨迹;最后,使用Maflah6.5对系统进行了仿真研究,仿真结果表明了其数学模型及控制方法的正确有效性。 相似文献
18.
The collision-free trajectory planning method subject to control constraints for mobile manipulators is presented. The robot task is to move from the current configuration to a given final position in the workspace. The motions are planned in order to maximise an instantaneous manipulability measure to avoid manipulator singularities. Inequality constraints on state variables i.e. collision avoidance conditions and mechanical constraints are taken into consideration. The collision avoidance is accomplished by local perturbation of the mobile manipulator motion in the obstacles neighbourhood. The fulfilment of mechanical constraints is ensured by using a penalty function approach. The proposed method guarantees satisfying control limitations resulting from capabilities of robot actuators by applying the trajectory scaling approach. Nonholonomic constraints in a Pfaffian form are explicitly incorporated into the control algorithm. A computer example involving a mobile manipulator consisting of nonholonomic platform (2,0) class and 3DOF RPR type holonomic manipulator operating in a three-dimensional task space is also presented. 相似文献
19.
We consider the inverse kinematic problem for mobile manipulators consisting of a nonholonomic mobile platform and a holonomic manipulator on board the platform. The kinematics of a mobile manipulator are represented by a driftless control system with outputs together with the associated variational control system. The output reachability map of the driftless control system determines the instantaneous kinematics, while the output reachability map of the variational system plays the role of the analytic Jacobian of the mobile manipulator. Relying on a formal analogy between the kinematics of stationary and mobile manipulators we exploit the extended Jacobian construction in order to design a collection of extended Jacobian inverse kinematics algorithms for mobile manipulators. It has been proved mathematically and confirmed in computer simulations that these algorithms are capable of efficiently solving the inverse kinematic problem. Moreover, a choice of the Jacobian extension may lay down some guidelines for the platform‐manipulator motion coordination. © 2002 Wiley Periodicals, Inc. 相似文献