欠驱动多指机械手优化设计与抓取稳定性分析

针对欠驱动机械手多模式抓取问题,提出了一种手指可拆卸、具有复合抓取功能的欠驱动机械手。为了研究欠驱动手的抓取性能,分别研制了一种弹簧自适应3指节手指机构和一种双四连杆3指节手指机构,两种手指机构均使用四连杆机构的运动原理。手指的性质对欠驱动机械手的抓取稳定性影响很大,对欠驱动机械手单个手指的属性进行分析,分析了关节接触点位置及接触力对抓取稳定性的影响,提出了接触力及力矩平衡的研究分析方法,探讨了影响抓取稳定性的因素。     

一种新型灵巧手的设计与仿真分析

为了提高BHG-1型灵巧手的自适应性和拟人化,设计了一种欠驱动手指机构,以较少的驱动器数目获得较多的自由度,降低装置对控制系统的要求。采用拉格朗日方程建立了2自由度欠驱动手指的动力学模型,并利用Adams软件对其进行了动力学的仿真与分析。     

Control of a fuel cell based on the SIRMs fuzzy inference model

A typical working mode for the fuel cell hybrid system is that the fuel cell produces constant power output while the auxiliary storage energy device such as ultracapacitor or battery provides the deviation between the desired power demand and the value of the actual operation. This paper concentrates on the control of the fuel cell flow system. The system which is like an under-actuated mechanical system needs to control two objects (the cathode pressure and the air flow) with one manipulated variable (the set voltage of the air mass flow controller). A SIRMs-based fuzzy inference model is successfully implemented in the system. Online random search optimization algorithm based on Simulink C-S functions is developed to adjust the parameters in the model. By alternative control of the two objects, experimental results demonstrate the realization of the control strategy with one adjustment means.     

MINIMUM-TIME TRAJECTORIES FOR REDUCING LOAD SWAY IN QUAY-CRANES

An investigation into near-minimum-time trajectory planning for a quay-crane is presented in this paper. A dynamic model that captures swinging and pitching motions of the load carried by the crane is developed. An algorithm to obtain near-minimum-time input commands for positioning the crane, that utilises the developed dynamic model, is presented. It is shown that only a modest reduction in the operating speed is required to move a crane without residual load sway. Furthermore, ignoring the reeving geometry and assuming that the quay-crane can be modelled as a crane carrying a point mass at the end of a single rope is shown to be inadequate. Computer simulations using the operating parameters of a full scale quay-crane are presented to verify the results.     

Swing-up control strategies for a reaction wheel pendulum

Control of a reaction wheel pendulum, a prototype of an under-actuated system, is easily done using switching control strategies, which combines swing-up control and balancing control schemes. In this article, two novel swing-up control strategies for a reaction wheel pendulum have been proposed. The first swing-up control strategy treats the oscillations of the pendulum as perturbations from the bottom equilibrium point. The second swing-up control is based on interconnection and damping assignment-passivity based control (IDA-PBC). IDA-PBC preserves Euler Lagrangian structure of the system and gives more physical insight about any mechanical system. Any balancing controller can be coupled with the proposed swing-up control strategies to stabilise the pendulum at the top unstable equilibrium position. The control task of balancing the pendulum in top upright position is completed by switching from swing-up scheme to the balancing scheme at the point where the pendulum is very near to the top equilibrium point. Proposed swing-up control strategies have been implemented in real time in switching mode. The two proposed swing-up control schemes provide fast responses as compared to existing energy based schemes.     

Dynamic coupling switching control incorporating Support Vector Machines for wheeled mobile manipulators with hybrid joints

The hybrid joints can be switched to either active (actuated) or passive (under-actuated) mode as needed (Li, Ming, Xi, & Shimojo, 2006), in this paper, dynamic coupling switching control incorporating Support Vector Machines (SVMs) is developed for wheeled mobile manipulators with hybrid joints. The hybrid actuated robot dynamics is a mixed under-actuated and actuated model. In order to approximate the high dimension unmodelled dynamics, the SVMs matrix and its operator are proposed. Considering the joint switching as an event, the event driven switching control strategy is used to ensure that the system outputs track the given bounded reference signals within a small neighborhood of zero, and guarantee semi-global uniform boundedness of all closed loop signals, and the switch stability. The effectiveness of the proposed controls is verified through extensive simulations.     

具有形状自适应的欠驱动拟人机器人手指

为了实现使用较少驱动器获得较多的自由度,从而在不增加控制难度的前提下,更好地抓取物体以及增加手的拟人化,需要研究欠驱动机械手指装置。提出了一种新的设计思想,以此为指导设计了一种机械手指装置,并对其主要设计参数进行了详细分析。试验证明,该装置可以作为机器人拟人手的一个手指或手指的一部分,用以实现机器人拟人手较少驱动器驱动较多的手指关节自由度,并具有抓取不同形状、尺寸的物体的自适应性,降低了装置对控制系统的要求。该装置外形与人手的手指相似,结构简单、可靠、易加工、体积小和重量轻。     

基于LQR和变论域模糊控制的吊车防摆控制

针对吊车这类非线性欠驱动系统。提出一种基于LQR和变论域模糊控制的消摆控制方法．先将该系统分解为垂直运动和水平运动两个子系统;然后用变论域方法寻找最优反馈增益,从而解决了在绳长连续变化时,吊车系统的防摆优化控制问题．仿真结果表明了该方法的有效性。     

基于DSP和FPGA的欠驱动灵巧手控制系统设计

针对所研制的欠驱动灵巧手抓持运动特性和功能要求等问题,设计了一种主从控制和自主控制相结合的复合式递阶控制系统。硬件系统采用了DSP和FPGA相结合的主从结构模式,软件系统使用了模块化设计思想,同时探讨了基于遗传算法的欠驱动灵巧手抓持规划问题。最后进行相关抓持性能测试实验。实验结果表明:该控制系统响应迅速、性能稳定、可靠性高、人机友好、复杂度降低,可使欠驱动灵巧手有效地完成对不同物体的包络抓持。