Applied Mechanics and Materials Vols. 284-287

Abstract: The electric scooter with nonlinear friction force of the transmission belt made the hybrid recurrent neural network (HRNN) control system with degenerated tracking responses. In order to overcome this problem, a hybrid recurrent wavelet neural network (HRWNN) control system is proposed to control for a permanent magnet synchronous motor (PMSM) driven electric scooter. The HRWNN control system consists of a supervisor control, a RWNN and a compensated control with adaptive law. The on-line parameter training methodology of the RWNN can be derived using adaptation laws and the Lyapunov stability theorem. The RWNN has the on-line learning ability to respond to the system’s nonlinear and time-varying behaviors. To show the effectiveness of the proposed controller, comparative studies with HRNN control system is demonstrated by experimental results.

Abstract: There exist an infinite number of right-half plane zeros in the transfer function relating the joint torque input to the tip contact force output for a constrained single-link flexible arm. Since the non-minimum phase nature is the cause of instability or stability but caused the smaller control bandwidth. In order to overcome the inherent limitations caused by the non-minimum phase nature, a new input induced by the measurement of joint angular acceleration and a output generated using the measurements of contact force and root shear force are defined. A necessary and sufficient condition is derived such that all poles and zeros of the new transfer function lie on the imaginary axis. The passive integral control is designed to accomplish the regulation of the contact force. The excellent performance of the passive integral controller is verified through numerical simulations.

Abstract: The traditional proportional-integral-derivative (PID) controllers are still the most popular controllers in the majority of manufacturing industries. However, its control parameters are difficult to regulate with the environment changing. The resistance value of the memristor dynamically depends on its charge and flux changing, which can be regarded as a tunable parameter element in the modern control system. In this paper the newest circuit element is applied to replace the synapse weight and realize self-regulation of PID controller parameters with the environment changes in the control network. It is possessed of many characteristics such as simple structure, good robustness, high reliability and adaption to the changing environment. Then the position tracking curves and parameter varying curves are obtained by experimental simulation according to the different learning rules. The experimental simulation results show that the memristive PID control network can realize on-line control and identification with higher control reliability and better adaptability.

Abstract: This paper describes a novel control algorithm for inverter-based distributed generators (DG) to maintain a continuous voltage and power supply for the critical and voltage sensitive loads in micro-grids when a serious fault on the grid side occurs. Based on a set of given system conditions, the proposed algorithm can automatically switch the DG inverter between the power-controlled and the voltage-controlled modes. In this paper, to develop a feasible control algorithm, some operating conditions are firstly assumed and the proposed control strategies are then addressed. The feasibility and effectiveness of the proposed control scheme are verified with comprehensive simulation studies carried out in the PSIM software environment. The simulation results confirm some merits of the proposed control method. It is worthwhile noting that the proposed control algorithm can easily be implemented using digital controllers for practical applications.

Abstract: In this paper, an intelligent garbage can model-based differential evolution algorithm (IGCMDE) is proposed to simulate human social organization by its population system, based on the differential evolution algorithms (DEs) and the logical framework of the garbage can decision model with group meeting. When faced with issues such as unclear goals and technologies, participators turnover, etc., representatives of all participating parties will communicate, argue, compromise and adapt with each other, in order to find a solution to the problems. Group meetings are conducted to choose the best solution in a more objective, reasonable and efficient way. At last, we used IGCMDE to optimize the fuzzy controller with fuzzy logic control theory. We present a method for daylight blending control with two novel contributions: 1) smart luminance sensing; 2) daylight luminance control. The proposed method was implemented as an intelligent lighting system in a parking tower environment. The result demonstrated that IGCMDE possesses an excellent search performance and the intelligent lighting system showed significant energy savings.

Abstract: An assembly sequence planning (ASP) method that combined the advantages of ant colony system (ACS) and Max-Min ant system (MMAS) is proposed. To identify the best sequence easily, five optimization criterions are automatically quantified, including reorientation, parallelism, continuity, stability and auxiliary stroke, and then integrated into the multi-objective heuristic and fitness functions of ant colony optimization (ACO). To improve the search capability for the global-best sequence, several measures are presented from aspects of determining number of ant, max-min pheromone limits, performance appraisal for initial components allocation and the group method for same components. The ASP algorithm based on Max-Min ant colony system (MMACS) is proposed. An assembly planning system AutoAssem is developed based on Siemens NX platform, and the actual effectiveness of each optimization measure is testified through case study of a valve.

Abstract: In this paper, an H∞ state feedback control problem for a discrete–time singular plant with device delay is considered. The device delay often appears in computer based control systems, networked circuits systems, communication systems, process control systems and so on. And the state feedback control law is supposed to include possible time varying transmission delay within an interval. In this case, we derive a set of LMI-based sufficient conditions for the analysis and the delayed controller synthesis problems, respectively, via a finite sum inequality approach. In order to show the efficiency of the proposed method, a numerical example is presented at the end of this paper.

Abstract: This paper utilizes the Improved Particle Swarm Optimization (IPSO) with bounded constraints technique for adjusting the gains of a Proportional-Integral-Derivative (PID) and Iterative Learning Control (ILC) controllers. This study compares the conventional ILC-PID controller with proposed IPSO-ILC-PID controller. A cycloid trajectory for mimicking the real industrial motion profile is applied. Two system plants with nonminimum phase are numerically simulated. Proposed IPSO with bounded constraints technique is evaluated on one axis of linear synchronous motor (LSM) with a PC-based real time controller. Simulations and experiment results show that the proposed controller can reduce the error significantly after two iterations.

Abstract: This work presents an effective method on computing strict minimal siphons and elementary siphons based on the concept of initial resource weighted digraphs for a class of generalized Petri nets, namely WS³PR. In addition, the controllability conditions of dependent siphons are developed. Monitors are added for the elementary siphons only and the controllability of a dependent siphon is ensured by properly supervising its elementary siphons. Through fully investigating the structure of the net, especially weight information, the set of elementary siphons obtained by the proposed method is more compact and well suits for WS³PR. An example is illustrated to demonstrate the proposed method.

Abstract: In this paper, a novel fuzzy simplex sliding-mode controller is proposed for controlling a multivariable nonlinear system. Here, the fuzzy logic control (FLC) algorithm and simplex sliding-mode control (SSMC) theory are integrated to improve the system states response and to reduce system states chattering phenomenon of the controlled system for simplex control method. Hence, from this motivation yields the so-called fuzzy simplex sliding mode control (FSSMC) scheme. the fuzzy logic control algorithm and simplex sliding mode control algorithm is integrated to improve the system states response and chattering phenomenon. In this paper, at first, we introduce the principle of simplex method, and then develop the fuzzy controls based on the simplex method. Finally, a numerical example is proposed to illustrate the advantages of the proposed controllers, the simulation results demonstrate that the fuzzy simplex type sliding mode control scheme is a good solution to the chattering problem in the simplex sliding mode control.