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.     

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.     

Using chaotic maps for 3D boundary surveillance by quadrotor robot

Chaotic maps have been shown to be suitable for applications that require unpredictable behavior. In this paper, the chaotic maps are used for motion planning and control of a quadrotor for boundary surveillance purposes. The chaotic motion would prevent anticipation of the future movement of the quadrotor, especially in hostile situations where an intruding opponent exists. The chaotic trajectories are constructed based on a closed three-dimensional curve representing the boundary. It is demonstrated that the proposed algorithm for 3D planning generates chaotic paths by investigating the Lyapunov exponents. The desired unpredicted trajectory is used as input to an under-actuated control system. The performance of the algorithm is shown by simulation of the control system applied to the dynamic model.     

欠驱动柔性胸鳍仿生设计及仿真

为了进一步提高咽颌运动模式鱼类胸鳍仿生机构的性能,以实际鱼类胸鳍的结构和驱动控制机理为基础,采用欠驱动技术设计了一套新型的柔性胸鳍仿生机构,建立其运动学和动力学模型,并采用Matlab对其性能进行了仿真分析。从仿真结果来看,所建立的新型柔性胸鳍仿生机构及其运动学、动力学模型是合理、有效的。它不但能够较好的模拟胸鳍的各种操纵运动,而且减少了驱动装置的数量,降低了系统的复杂性。从而为深入研究鱼类胸鳍的推进机理和新型水下操纵工具的设计提供了一定的基础和保障。     

A new algorithm to maintain lateral stabilization during the running gait of a quadruped robot

This paper presents a new uncoupled controller (based on a Kinetic Momentum Management Algorithm, KMMA) which allows a quadrupedal robot, whose operation is simple and fast, to run using a symmetrical gait patterns in a wide variety of scenarios. It consists of two tasks: calculating the lateral position and speed of the fore swinging leg when it next makes contact with the ground; and controlling the roll angle by mean of inertia forces using the stance legs.The KMMA provides the benefits of modulation and the synchronization typically presented in CPG (Central Pattern Generation) models. Furthermore, it is able to maintain the locomotion parameters (such as stroke frequency of gait pattern) when the robot runs in a highly disturbed environment, thus resulting in a lower energy consumption. Additionally, the uncoupled scheme of the leg makes the operation computationally cheap, thus avoiding the use of a Virtual Actuator Control or a Hybrid Zero Dynamics.The performance of the KMMA has been verified by means of co-simulation (using ADAMS and MATLAB) with a highly realistic model of a quadruped robot with uncoupled legs. The performance of the algorithm has been tested in different situations in which the following variables have been varied: frontal velocity, turning ratio, payload, external disturbances and terrain slope. Successful results in terms of stability, energy efficiency, and adaptability to a complex locomotion environment have been obtained.     

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。     

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.     

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。     

Anti-swing control for 2-D under-actuated cranes with load hoisting/lowering: A coupling-based approach

In this paper, we present a coupling-based anti-swing control for 2-dimensional (2-D) under-actuated cranes with load hoisting/lowering, which achieves precise trolley positioning, accurate load hoisting/lowering and efficient load swing suppression. Compared to the existing methods for cranes with load hoisting/lowering, this paper introduces a novel composite signal which enhances the coupling behavior between the actuated and under-actuated variables. Then, based on this signal and its derivatives, we constructed our controller without linearization or approximation operations to the original nonlinear crane model. In addition, some common assumptions related to the rope length and original model among existing works are further relaxed in this paper. Last, we provide numerical simulation results to validate the feasibility and effectiveness of the proposed controller.     

欠驱动机器人动力学运动规划的动态子空间法及控制

欠驱动机器人的关节空间运动是通过主、被动关节间的动力学耦合实现的,系统运动可能发生动力学耦合奇异,使欠驱动机器人的动态操作性能严重降低。针对一般具有任意多个被动关节的开链欠驱动机器人系统,基于动力学分析提出一种优化控制方法,其核心是在欠驱动机器人的全部耦合运动空间中,根据动力学耦合操作性度量,动态构造有限个覆盖全部耦合运动空间的具有最佳耦合度的子空间,使发生在这些子空间中的耦合运动具有余度驱动的特点,从而实现提高欠驱动机器人的动力学耦合度的优化控制。提出的方法通过平面四连杆机器人进行仿真,仿真结果证明了这种方法是可行的。