Papers by Keyword: Control Algorithms

Abstract: The subject of this work is to develop a control system for the two degree of freedom robot manipulator. Manipulators play an increasingly important role not only in flexible automation production systems but also in medicine and rehabilitation process [3]. High-speed and high-precision trajectory tracking are indispensable capabilities for versatile applications of manipulators. Even in well-known industrial applications manipulators are characterized by structural and / or unstructured uncertainty. Through structural uncertainty we miss a situation in which we have a dynamic model of the object, but because of the uncertainty unknown parameters such as load, inaccuracies in constant torque actuators etc. to create a properly working control system is a difficult issue. In contrast, unstructured uncertainty is related to the unknown of the dynamic model, which may be due to many reasons such as the presence of high-frequency modes of the manipulator, neglected time-delays, nonlinear friction etc. In this case, when the dynamic model of the system is not known a priori (or not available), the system must first be identified, then the control law is developed based on the estimated model [5, [6[7].These problems cause that it is very difficult to find good control system but simple. In this case, the different algorithms for control system of the manipulator was proposed. The first classical PD controller was tested. Next the system design for PD controller with compensation of gravitational forces.

Abstract: Navigation and routes planning for a group of unmanned surface vessels (USV) jointly moving in complex environment, including circumvention of seashore and islands, are important applications of computer-based decision-making support systems. A group of objects as an open complex system includes several hierarchy levels and may be controlled by a decision-maker supported by information-analytical software and methodical maintenance. Planning, as a stage of management, includes an a priori phase guidance for all objects in the group, coordinated in both time and directions of approach to the target set restricted by a set of obstacles. A discrete system of priorities reflects relative preferences of importance and allows choosing routes optimal in different senses. One can formalize such tasks in terms of different mathematical models including control problems of formation motion, theory of extreme networks and interval analysis. The paper bases on guaranteed approach to control of dynamic objects under uncertainty. Unified mathematical descriptions of shores, routes of individual objects and the whole group may be given in terms of hierarchic (i)-systems. This allows to reconcile data on geography, environment, object characteristics, peculiarities of control systems and data transmission, including sources and causes of uncertainty, and to describe movement of a group as an extreme problem of control and estimation. The results of computer simulation are considered. One may use similar models to explore economic aspects in application of heterogenic complex of autonomous surface and underwater vessels.

Abstract: This article presents the main aspects of modeling, design and development of a manipulator type parallelogram 3-DOF for the control of path tracking with open architecture, this model allow easy maintenance and program modification. The design and manufacturing tasks was aided by CAD/CAE/CAM technology. The assembly and commissioning was carried out by the integration of the mechanical and electronic components. The integration and evaluation of the control algorithms during the prototype manipulation was obtained by the kinematic and dynamics models and Lagrange equations of motion. Finally, results of monitoring control paths are present through testing in the joint and cartesian spaces, the results showed the optimum performance of the manipulator under different parameters of control.

Abstract: One challenge in the use of semi-active technology is in developing nonlinear control algorithms that are appropriate for implementation in full-scale structures. Based on the basic characteristics of magnetorheological (MR) damper, the structural control algorithms are introduced. The nonlinear control algorithms are systematically reviewed from the aspects including clipped optimal control, LQR control, and Lyapunov stability control. Finally, the existed problem in application and the future developing in research on the structural control algorithms are summarized respectively.

Abstract: As the long transmission line, complex mechanism, poor performance of regulation and control and low sensitivity of mechanical let-off, so it can not meets the requirements of stable tension. Therefore, the let-off mechanical was improved. This paper takes let-off system of SAURER400 rapier loom as experimental subject, mathematical modeling to every parts of loom, and takes simulation and comparison. The simulation results show the improvement of mechanical can meet the basic requirements of weaving, and it indicates the works that done former are effective and correct.

Abstract: Zero crossing points of Back-Electromotive force (EMF) is the most mature and widely used method of the speed sensorless control of brushless DC motor (BLDCM). However, with the poor performance from standstill to low speed, it is not suitable for the position servo system. Therefore, this paper first analyzes several conventional speed sensorless control schemes in the BLDCM, then presents a novel control algorithms for the BLDCM. In the proposed method, the short pulse sensing method for the rotor position in the Start-Up process and self-synchronization with zero cross points of back-EMF are combined together. As a result, the BLDCM used in the position servo system can be easily controlled from zero to high speed, the theoretical analysis is verified by the simulation results based on Matlab, it shows that the proposed algorithms can improve the performances of position servo system compared with the conventional methods.

Abstract: Electromechanical control CVT (EM-CVT) is a new type of continuously variable transmission, and its ratio quality is an important parameter validated the performance of vehicle. In order to study the dynamical coupling technology between EM-CVT and engine under the running state of vehicle, the special character of two working models is obtained by engine experiment; according to the principle of the EM-CVT, the relation between vehicle speed and ration is theoretically analyzed. Based on the basic theory of PID control, the improved PID control algorithm is proposed for the speed ratio control of the EM-CVT, and experimental verification is made. The experimental results show that there is a significant effect on the system with this algorithm.

Abstract: For some optical tracking measurement systems, because their size, weight and space structure are very strict restrictions, DC servo motors have to drive the loads through the several stages of gear transmission. For such a nonlinear controlled object, it is difficult to obtain acceptable control performance applying the traditional controller design method. In the paper, firstly, establish such a non-linear system dynamic model, and consider intelligent control algorithm to inhibit mechanical resonance effect for the control system performance. In order to achieve real-time control easily, the paper suggests a fuzzy numeric model with the self-regulating factor based on analytic expression for such a non-linear system. The result demonstrates that the fuzzy controller is very effective in applications. This work provides a new thought for a controller design to inhibit the low mechanical resonance frequency.

Abstract: Self reconfiguring robots are complex robotic systems composed of a finite number of modules, where each module of the system is considered to be a simple agent. Based on this con¬text, the reconfi¬guration represents the process of re-arranging each agent of the robotic system in order to have a working system. One versatile method to determine the most adequate movement and reconfiguration algorithms can be done us¬ing modeling methods and tools. Using this approach, the control algorithms necessary to drive such a system can be modeled, tested and implemented in an embedded system much easier than in a classical approach. This paper presents the case of a self reconfiguring robot for which, a reconfiguration algorithm and a movement algorithm were determined, analyzed, tested and validated.

Abstract: The paper presents a scaled experimental stand for applying different algorithms onto a braking system with anti-lock capability, in order to determine the best way to control the braking process. The stand consists of a test wheel with an electro-mechanic brake caliper rolling against a powered tambour track. The angular velocities of both rolling wheel and track are monitored by a PC using custom hardware and software. The functional parameters of the test stand can be modified, thus employing different approaches for the anti-lock function of the braking process.