1,721,000 research outputs found
Robustified anti-windup via switching adaptation
No full textAn adaptive approach is proposed to address the problem of robustification (and performance loss reduction) of anti-windup compensation in the presence of large uncertainties. The approach relies on the augmentation of the anti-windup compensator with an adaptive robustifying filter; a constructive procedure is provided for designing such a filter. The use of adaptation allows to reduce the conservativeness of previous robust approaches to what is needed to preserve stability with respect to the uncertainty actually present on the plant during operation, as detected by input and output plant measurement
Switching adaptive realization of a weakened anti-windup compensator
No full textA switching adaptive robustified anti-windup compensator is proposed in order to improve the performance in the case of (possibly time-varying) large uncertainties, where previous purely robust solutions would be too conservative. Given a set of candidate controllers, the switching algorithm tries to determine and switch in the loop the most aggressive controller for which a small gain stability condition is satisfied according to the measured data (i.e. for the uncertainty currently affecting the plant), thus reducing the conservatism associated to previous robust solutions. An example shows the enhanced performance of the new algorithm
A switching nonlinear MPC approach for ecodriving
Full text linkIn recent years many works focusing on improved vehicle fuel efficiency through advanced control have been carried out, reflecting the high interest in ecodriving of vehicles. Although many studies have shown the potential that optimal control based ecodriving can offer, these solution are often difficult to be translated into online control strategies, one of the reasons being the complexity of the optimal control problem and therefore the computational burden. To cope with this a novel online approach, based on switching Nonlinear Model Predictive Control (NMPC), is proposed. The NMPC strategy is developed for the case of conventional vehicles, where gear shifting and longitudinal dynamics are controlled. It is shown that our proposal can operate in real time, while recovering most of the performance achievable by an offline optimal solution. The development of the method is described in detail and its performance is analyzed. The results show that the proposed NMPC can successfully solve the ecodriving task and seems a good compromise between computational burden and performance suitable for field implementation
Approximate optimal control of internal combustion engine test benches
No full textThis paper proposes the design of an optimal simultaneous control of speed and torque for dynamic internal combustion engine test bench by means of a dynamic extension to the state of the system which allows to avoid the explicit solution of the Hamilton-Jacobi-Bellman partial differential equation. To this end, a dynamic control law is firstly designed based on a simplified and approximate model of the test bench and then modified in order to cope with non-modeled dynamics and nonlinearities. The control is designed on this basis and its performance of the control law is tested and validated on an accurate simulator of the internal combustion engine test bench
Optimal control of internal combustion engine test benches equipped with hydrodynamic dynamometers
No full textThis paper considers the problem of tracking dynamic reference profiles for rotational speed and torque at the crankshaft of an internal combustion engine at a test bench. The test bench is equipped with a hydrodynamic dynamometer that can only load the internal combustion engine. A proper formulation of this tracking problem with input constraints by nonlinear functions to the state equations of the system and an extension of the state to approximately solve the resulting optimization problem is used to design a control law achieving at the same time a criterion of optimality. Simulation results using a high-quality simulator of the test bench show the performance of the proposed approach
Optimal control with input constraints applied to internal combustion engine test benches
No full textOptimal control of nonlinear systems provides a major challenge in control engineering. Constraints on the input signals are common to many real-world applications and render the problem to be tackled even more complicated. This paper proposes a method to map the input constraints by nonlinear functions to the state equations of the system, afterwards an approximation of the solution of the resulting optimization problem is calculated by means of a dynamic extension to the state of the system. The approach is applied in the control of test benches for internal combustion engines, where speed and torque references need to be tracked at the crankshaft of the engine. Simulation results using a high-quality simulator, also regarding effects that have not been included in the model for controller design, show the performance of the proposed approach. © IFAC
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