Topic
Open-loop controller
About: Open-loop controller is a research topic. Over the lifetime, 16148 publications have been published within this topic receiving 224014 citations. The topic is also known as: non-feedback controller & open-loop control law.
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01 Dec 2010TL;DR: A simulation was used to assess the system performance given the theoretical results of the controller's parameters with a unique exoskeleton system (EXO-UL7) and verify the semi-global asymptotic stability of the system.
Abstract: An upper limb exoskeleton is a wearable robotic system that is physically linked to the arm of the human operators and its seven actuated degrees of freedom (DOF) match the seven DOF of the human arm. The stability of such a system is critical given the proximity of its human operator. A new PID controller is developed which guarantee asymptotic stability for this class of robotic manipulators. A simulation was used to assess the system performance given the theoretical results of the controller's parameters with a unique exoskeleton system (EXO-UL7). The simulation also verify the semi-global asymptotic stability of the system. The proposed methodology eliminates the need of the system's dynamics model for the purpose of designing the controller. It provides an analytical tool for the controller design that is traditionally preformed experimentally (parameter tuning).
84 citations
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TL;DR: In this article, a hybrid current controller is proposed for the permanent-magnet synchronous motor (PMSM), which is a simultaneous combination and contribution of the hysteresis current controller and the ramp comparator.
Abstract: Recently, the permanent-magnet synchronous motor (PMSM) has found widespread utilization in modern adjustable AC drives. This is achieved by using current-controlled voltage source inverter (VSI) systems. Because of its ease of implementation, fast current control response and inherent peak current-limiting capability, hysteresis current control is considered as the simplest technique used to control the motor currents for an AC machine. On the other hand, the ramp comparator controller has some advantages, such as limiting maximum inverter switching frequency to the carrier triangular waveform frequency and producing well-defined harmonics. In order to take advantage of the position features of both these two controllers, this paper presents the design and software implementation of a hybrid current controller. The proposed intelligent controller is a simultaneous combination and contribution of the hysteresis current controller and the ramp comparator. Comparisons using simulations on a 0.9-kW PMSM confirm that the proposed hybrid current controller gives better performance and has the advantage of conceptual simplicity. In particular, harmonic spectra of the stator current, obtained using a fast Fourier transform (FFT), are used for comparison purposes.
84 citations
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TL;DR: The adaptive controller to achieve point stabilization, trajectory tracking, and path following is synthesized via the adaptive backstepping approach and implemented into a high-performance field-programmable gate array chip using hardware/software codesign technique and system-on-a- programmable-chip design concept with a reusable user intellectual property core library.
Abstract: This paper presents an embedded adaptive robust controller for trajectory tracking and stabilization of an omnidirectional mobile platform with parameter variations and uncertainties caused by friction and slip. Based on a dynamic model of the platform, the adaptive controller to achieve point stabilization, trajectory tracking, and path following is synthesized via the adaptive backstepping approach. This robust adaptive controller is then implemented into a high-performance field-programmable gate array chip using hardware/software codesign technique and system-on-a-programmable-chip design concept with a reusable user intellectual property core library. Furthermore, a soft-core processor and a real-time operating system are embedded into the same chip for realizing the control law to steer the mobile platform. Simulation results are conducted to show the effectiveness and merit of the proposed control method in comparison with a conventional proportional-integral feedback controller. The performance and applicability of the proposed embedded adaptive controller are exemplified by conducting several experiments on an autonomous omnidirectional mobile robot.
84 citations
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TL;DR: Some dual rate operations are used to model the controller as well as the controlled plant, using model-based cancellation controllers designed using this approach and promising results are obtained.
Abstract: In many industrial control applications the control action updating can be faster than the output measurement, leading to multirate controllers. In this paper, some dual rate operations are used to model the controller as well as the controlled plant. The controller design is model-based and depends on the input to be tracked. The controller is split into two parts acting at different sampling rates and its design is approached based on the characteristics of each available sampling rate. The control target is to reach the similar performances to those the faster single rate controller would achieve. Model-based cancellation controllers are designed using this approach and promising results are obtained.
83 citations
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TL;DR: In this paper, a fuzzy logic proportional plus conventional integral controller is proposed for damping local modes and inter-area modes of oscillations in a multi-machine power system, which combines the advantages of a FLC and a conventional PI controller.
83 citations