A general dynamics and control model of a class of multi-DOF manipulators for active vibration control

A general dynamic model of a class of parallel platforms for vibration control applications based on Kane's method is presented. A general parallel platform is composed of a moving platform, a base platform, and i limbs with identical kinematic structure. Each limb connects the mobile platform to the base platform by j + 1 hinges and j struts, where the prismatic actuator is fixed at one of the struts. The hinges can be replaced by any other kind of conventional hinges or flexure hinges. The control system architecture based on mixed H₂/H_∞ synthesis method is introduced for a class of parallel platforms as a multiple-input/multiple-output (MIMO) problem for the purpose of active vibration isolation. A case study is illustrated and the theoretical analysis is validated at last.     

片状脆性材料拾放机械手控制系统设计与实现

针对质子交换膜燃料电池(PEMFC)膜电极的制备,提出一种用于拾放片状脆性材料的五自由度机械手,并重点研究其控制系统的设计与实现.为满足膜电极制造工艺中提出的精确力/位控制、精确对位和快速拾放的控制要求,提出基于运动模式切换和力/位双闭环控制策略,基于视觉对准的视觉纠姿系统和基于速度、加速度前馈的位置控制方法.这些控制策略和方法已成功运用于片状脆性材料拾放机械手的控制系统中,控制效果良好,亦可推广到集成电路(IC)制造装备等其他领域.     

机器人柔性抛光机床的力控制系统的建模与辨识

机器人柔性抛光系统中,力控制系统是重要的组成部分.力控制系统对抛光加工性能有重要的影响,直接关系着抛光质量.该力控制系统实际上是一个闭环的交流伺服系统,对力控制系统的建模为抛光系统的动态和静态性能分析提供了理论基础.     

Design and implementation of a new fuzzy PID controller for networked control systems

This paper presents a practical network platform to design and implement a networked-based cascade control system linking a Smar Foundation Fieldbus (FF) controller (DFI-302) and a Siemens programmable logic controller (PLC-S7-315-2DP) through Industrial Ethernet to a laboratory pilot plant. In the presented network configuration, the Smar OPC tag browser and Siemens WinCC OPC Channel provide the communicating interface between the two controllers. The paper investigates the performance of a PID controller implemented in two different possible configurations of FF function block (FB) and networked control system (NCS) via a remote Siemens PLC. In the FB control system implementation, the desired set-point is provided by the Siemens Human-Machine Interface (HMI) software (i.e, WinCC) via an Ethernet Modbus link. While, in the NCS implementation, the cascade loop is realized in remote Siemens PLC station and the final element set-point is sent to the Smar FF station via Ethernet bus. A new fuzzy PID control strategy is then proposed to improve the control performances of the networked-based control systems due to an induced transmission delay degradation effect. The proposed strategy utilizes an innovative idea based on sectionalizing the error signal of the step response into three different functional zones. The supporting philosophy behind these three functional zones is to decompose the desired control objectives in terms of rising time, settling time and steady-state error measures maintained by an appropriate PID-type controller in each zone. Then, fuzzy membership factors are defined to configure the control signal on the basis of the fuzzy weighted PID outputs of all three zones. The obtained results illustrate the effectiveness of the proposed fuzzy PID control scheme in improving the performances of the implemented NCS for different transportation delays.     

A novel design strategy for iterative learning and repetitive controllers of systems with a high modal density: Application to active noise control

This paper describes the application of a novel design strategy for iterative learning and repetitive controllers for systems with a high modal density, presented in the companion paper, on two experimental case studies. Both case studies are examples of active structural acoustic control, where the goal is to reduce the radiated noise using structural actuators. In the first case study, ILC is used to control punching noise. An electrodynamic actuator on the frame of the punching machine is driven by the ILC algorithm which takes advantage of the repetitiveness of the consecutive impacts to reduce noise radiation. In the second case study, an RC algorithm is used to control the noise radiated by rotating machinery, which is often mainly periodic. A piezoelectric actuator incorporated in the bearing is driven by the RC algorithm which is capable of reducing harmonics of the rotational frequency of the shaft. Both applications show the practical usefulness of the novel design strategy.