A Lyapunov approach is used to design regulators for systems subject to loss of control effectiveness. control effectiveness factors are used to quantify faults entering controlsystems through actuators. An adaptive ...
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A Lyapunov approach is used to design regulators for systems subject to loss of control effectiveness. control effectiveness factors are used to quantify faults entering controlsystems through actuators. An adaptive Kalman filtering algorithm is used to estimate the state as well as the amount of reduction of control effectiveness in a closed-loop setting. The state estimate is fed back to achieve the steady state regulation, while the control effectiveness estimate is used for the on-line tuning of the control law. The resulting regulator is guaranteed to be stable when the estimation error is sufficiently small. An aircraft longitudinal model is used to demonstrate the use of the Lyapunov method.
In this paper, a new self-tuning PID controller design scheme is proposed. The PID parameters are calculated on-line based on the relationship between the PID and generalized minimum variance control (GMVC) laws. In d...
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In this paper, a new self-tuning PID controller design scheme is proposed. The PID parameters are calculated on-line based on the relationship between the PID and generalized minimum variance control (GMVC) laws. In designing GMVC system, user-specified polynomials are computed by considering the pole-assignment in the controlsystem. Therefore, this scheme has approximate minimum variance properties with specified closed-loop time-constant. The newly proposed control scheme can also deal with unknown and/or varying process time-delays. The proposed control scheme is experimentally evaluated on a SISO air pressure controlsystem. Experimental results illustrate the effectiveness of this new scheme.
This paper describes an application of unfalsified control theory to the design of an adaptive controller for a nonlinear robot manipulator. A nonlinear `computed torque' control structure is employed. Four parame...
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This paper describes an application of unfalsified control theory to the design of an adaptive controller for a nonlinear robot manipulator. A nonlinear `computed torque' control structure is employed. Four parameters representing unknown masses, inertias and other dynamical coefficients are adaptively adjusted in real-time using an linear programming technique to optimally satisfy control-law unfalsification conditions. Simulations show that the method yields significantly more precise and rapid parameter adjustments than conventional continuous parameter update rules, especially when the manipulator arm is subject to sudden random changes in mass or load properties.
The paper investigates improvements in the turbocharged diesel engine transient response that can be attained when a turbocharger power assist system, consisting, for example, of an electric motor and a battery, is co...
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The paper investigates improvements in the turbocharged diesel engine transient response that can be attained when a turbocharger power assist system, consisting, for example, of an electric motor and a battery, is coupled to the turbocharger shaft. The method of investigation relies on formulating and solving numerically an appropriate minimum time optimal control problem. Comparison with a conventional turbocharged diesel engine response reveals the mechanism by which acceleration improvements are attained while maintaining high fuel efficiency and equivalent smoke emission levels. A feedback controller that generates responses qualitatively similar to the optimal ones is also described.
Over the last decade, multirate control has been an area of active research. Multirate output controllers (MROCs) sample the plant outputs at a faster rate than they change the plant inputs. Consequently, they offer g...
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Over the last decade, multirate control has been an area of active research. Multirate output controllers (MROCs) sample the plant outputs at a faster rate than they change the plant inputs. Consequently, they offer greater flexibility for controller design than conventional single-rate controllers. MROCs designed under H∞ performance have offered a new dimension in the design process. In this paper, we introduce the concept of lifting technique, LMIs and multirate output sampling and calculate the H∞ norm of the sampled-data controlsystems induced via multirate output sampling. Furthermore, in order to avoid dynamic parameters of MROCs, we use additional pole placement constraints to guarantee satisfactory transient behavior.
Numerous simulation studies have recently revealed the potential benefits of a neural network-based approach to direct adaptive control in the design of flight controlsystems. Foremost among the potential benefits is...
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Numerous simulation studies have recently revealed the potential benefits of a neural network-based approach to direct adaptive control in the design of flight controlsystems. Foremost among the potential benefits is greatly reduced dependence on high-fidelity modeling of system dynamics. However, the methodology has only recently been proven practical by demonstration in an actual flight system. This paper begins with an overview of the design of a nonlinear adaptive controlsystem for flight test on an unmanned helicopter test bed. Next, the design of an outer loop trajectory tracking controller as well as simulation results are presented. The paper concludes with the presentation of preliminary flight test results of the rate command system that document the actual performance of the controlsystem in flight.
Ideas from elementary graph theory and linear matrix inequalities (LMIs) are combined with logic-based switching to shed light on the various control strategies which are feasible in the leader-following (LF) framewor...
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Ideas from elementary graph theory and linear matrix inequalities (LMIs) are combined with logic-based switching to shed light on the various control strategies which are feasible in the leader-following (LF) framework for the formation flying of multiple spacecraft. LF can naturally be given a graph theoretic interpretation, and by doing so, non-trivial results can be obtained on some of its basic properties. control laws for LF are then derived using LMIs. These control laws are subsequently employed to propose logic-based switching schemes for the formation management.
A new formulation of predictive control which uses a closely to the continuous time plant related delta description is given. Starting with the derivation of an end-point state weighted generalized predictive controll...
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A new formulation of predictive control which uses a closely to the continuous time plant related delta description is given. Starting with the derivation of an end-point state weighted generalized predictive controller a polynomial controller representation is given and the theoretical value of the endpoint state weighting matrix is derived. The robustness with respect to additive plant/model mismatch is involved by the H∞ analysis. The Space Crystal Furnace TITUS is modeled using strongly coupled symmetric composite systems. A final simulation underlines the improved accuracy of the temperature gradient.
We examine the use of in-cylinder measurements for engine control, with emphasis on emissions control during cold start. First, the cold start emissions control problem is described. An overview of previous research i...
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We examine the use of in-cylinder measurements for engine control, with emphasis on emissions control during cold start. First, the cold start emissions control problem is described. An overview of previous research in the area of in-cylinder measurements for control is presented, including sensors for pressure and other quantities. Next, analysis of cylinder pressure is described. Lastly, a cold-start engine test stand, and preliminary experimental tests of cylinder pressure measurement and realtime processing are presented.
High intensity electromagnetic radiation has been demonstrated to be a source of computer upsets in commercially available digital flight controlsystems. Thus, there is a strong need to investigate its effect on stab...
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High intensity electromagnetic radiation has been demonstrated to be a source of computer upsets in commercially available digital flight controlsystems. Thus, there is a strong need to investigate its effect on stability and performance. In [3]-[5], electromagnetic disturbances were modeled with a continuous-time Markovian exosystem generating disturbance events. To analyze the effect of these disturbances, the radiated system was modeled as a discrete-time jump linear system with an appropriate set of transition probability rates. The linear systems in this model were all deterministic, hence this method rendered a worst-case stability analysis. In this paper, the technique is generalized by allowing stochastic perturbations to be randomly introduced by the exosystem model. A preliminary stability theory is developed, and an example is presented to compare stability boundaries for radiation parameters using this model against the worst-case scenario.
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