-
[show abstract]
[hide abstract]
ABSTRACT: This paper proposes a closed loop multivariable VGT/EGR control system for a turbocharged diesel engine. The control system is synthesized based on quantitative feedback theory to maintain robust stability and performance in the presence of model variations via sequential MIMO loop-shaping. Simulation results from a turbocharged diesel engine are included to illustrate the effectiveness of the proposed control design.
American Control Conference, 2008; 07/2008
-
[show abstract]
[hide abstract]
ABSTRACT: This paper presents a control design method for determining proportional-integral-type controllers satisfying specifications on gain margin, phase margin, and an upper bound on the (complementary) sensitivity for a finite set of plants. The approach can be applied to plants that are stable or unstable, plants given by a model or measured data, and plants of any order, including plants with delays. The algorithm is efficient and fast, and as such can be used in near real-time to determine controller parameters (for online modification of the plant model including its uncertainty and/or the specifications). The method gives an optimal controller for a practical definition of optimality. Furthermore, it enables the graphical portrayal of design tradeoffs in a single plot, highlighting the effects of the gain margin, complementary sensitivity bound, low frequency sensitivity and high frequency sensor noise amplification.
IEEE Transactions on Automatic Control 12/2003; · 2.11 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: This paper presents a control design algorithm for determining PI-type controllers satisfying specifications on gain margin, phase margin, and an upper bound on the (complementary) sensitivity for a finite set of plants. Important properties of the algorithm are: (i) it can be applied to plants of any order including plants with delay, unstable plants, and plants given by measured data, (ii) it is efficient and fast, and as such can be used in near real-time to determine controller parameters (for on-line modification of the plant model including its uncertainty and/or the specifications), (iii) it can be used to identify the optimal controller for a practical definition of optimality, and (iv) it enables graphical portrayal of design tradeoffs in a single plot (highlighting tradeoffs among the gain margin, complementary sensitivity bound, low frequency sensitivity and high frequency sensor noise amplification).
American Control Conference, 2003. Proceedings of the 2003; 07/2003
-
[show abstract]
[hide abstract]
ABSTRACT: This paper investigates limitations and design tradeoffs of the closed-loop sensitivity/performance of linear-time-invariant nonminimum-phase uncertain multiple-input-multiple-output plants, with I inputs and m outputs, where m ≤ l. It is shown that if rows i<sub>1</sub>...,i<sub>k</sub> of the plant transfer function form a k × l nonminimum phase transfer matrix, and if the design is such that the sensitivity gain of k - 1 rows among the rows i<sub>1</sub>,...,i<sub>k</sub> of the closed-loop transfer function is low, then by necessity the sensitivity gain of the remaining row is high. This sensitivity constraint is quantified with the help of the crossover frequency restriction of a specially constructed single-input-single-output transfer function that includes the right half plane zeros and poles of the k × l transfer matrix.
IEEE Transactions on Automatic Control 10/2002; · 2.11 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: A new design method is presented for the design of PLL loop
filters for carrier recovery, bit timing, or other synchronization loops
given the phase noise spectrum and noise level. Unlike the conventional
designs, our design incorporates a possible large decision delay and
S-curve slope uncertainty. Large decision delays frequently exist in
modern receivers due to, for example, a convolutional decoder or an
equalizer. The new design also applies to coherent optical
communications where delay in the loop limits the laser linewidth. We
provide an easy-to-use complete design procedure for second-order loops.
We also introduce a design procedure for higher order loops for
near-optimal performance. We show that using the traditional
second-order loop is suboptimal when there is a delay in the loop, and
also shows large improvements, either in the amount of allowed delay, or
the phase error variance in the presence of delay
IEEE Transactions on Communications 10/2001; · 1.68 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: A new design method is presented for the design of PLL loop
filters for carrier recovery, bit timing or other synchronization loops
given phase noise spectrum and noise level. Unlike the conventional
designs, our design incorporates a possible large decision delay and
S-curve slope uncertainty. Large decision delays frequently exists in
modern receivers due to, for example, a convolutional decoder or an
equalizer. The new design also applies to coherent optical
communications where delay in the loop limits the laser line width. We
provide an easy to use complete design procedure for second order loops.
We also introduce a design procedure for higher order loops for near
optimal performance. We show that using the traditional second order
loop is suboptimal when there is a delay in the loop, and also show
large improvements, either in the amount of allowed delay, or the phase
error variance in the presence of delay
Communications, 1999. ICC '99. 1999 IEEE International Conference on; 02/1999
-
[show abstract]
[hide abstract]
ABSTRACT: Impressions for removable partial dentures (RPDs) should provide an accurate and detailed record of the teeth and soft tissues. Removable partial denture casts should be exact replicas of the mouth to ensure that RPD frameworks fit accurately and are fully adjusted to oral structures. A comparative clinical evaluation was performed on the oral fit of RPDs made from impressions with either irreversible hydrocolloid (alginate) or condensation silicone. The difference between the two groups was found to be statistically significant.
Compendium of continuing education in dentistry (Jamesburg, N.J.: 1995) 03/1998; 19(2):200-2, 204-6.
-
O. Yaniv
[show abstract]
[hide abstract]
ABSTRACT: Ill-conditioned plants with delays are generally difficult to
control. Skogestad, Morari and Doyle (1988) applied the μ method to
achieve synthesis and analysis of such a problem. An alternative
synthesis using the Horowitz method for MIMO uncertain feedback systems
is applied to the same example. An economical bandwidth solution was
achieved without iterations. Design details and simulations are
presented
IEEE Transactions on Automatic Control 08/1992; · 2.11 Impact Factor
-
O. Yaniv
Control and Applications, 1989. Proceedings. ICCON '89. IEEE International Conference on; 02/1989
-
[show abstract]
[hide abstract]
ABSTRACT: This paper presents a robust noniterative algorithm for the design of controllers of a given structure satisfying frequency-dependent sensitivity specifications. The method is well suited for automatic loop shaping, particularly in the context of Quantitative Feed-back Theory (QFT), and offers several advantages, including (i) it can be applied to unstructured uncertain plants, be they stable, unstable or nonminimum phase, (ii) it can be used to design a satisfactory controller of a given structure for plants which are typically difficult to control, such as highly underdamped plants, and (iii) it is suited for design problems incorporating hard restrictions such as bounds on the high-frequency gain or damping of a notch filter. It is assumed that the designer has some idea of the controller structure appropriate for the loop shaping problem.
-
[show abstract]
[hide abstract]
ABSTRACT: This paper presents a method for the design of PID-type controllers, including those augmented by a filter on the D element, satisfying a required gain margin and an upper bound on the (complementary) sensitivity for a finite set of plants. Important properties of the method are: (i) it can be applied to plants of any order including non-minimum phase plants, plants with delay, plants characterized by quasi-polynomials, unstable plants and plants described by measured data, (ii) the sensors associated with the PI terms and the D term can be different (i.e., they can have different transfer function models), (iii) the algorithm relies on explicit equations that can be solved efficiently, (iv) the algorithm can be used in near real-time to determine a controller for on-line modification of a plant accounting for its uncertainty and closed-loop specifications, (v) a single plot can be generated that graphically highlights tradeoffs among the gain margin, (complementary) sensitivity bound, low-frequency sensitivity and high-frequency sensor noise amplification, and (vi) the optimal controller for a practical definition of optimality can readily be identified.
Automatica.
-
[show abstract]
[hide abstract]
ABSTRACT: The set of all stabilizing controllers of a given low order structure that guarantee specifications on the gain margin, phase margin and a bound on the sensitivity corresponds to a region in n-dimensional space defined by the coefficients of the controllers. For several practical criteria defined in the paper it is shown that the optimal controller lies on the surface of that region. Moreover, it is shown how to reduce that region to avoid actuator saturation during operation.
American Control Conference, 2004. Proceedings of the 2004;
-
[show abstract]
[hide abstract]
ABSTRACT: This paper presents performance limitations and a control design methodology for nonminimum phase plants of the pure delay type subject to robustness constraints. Of interest is the design of a set of controllers, for which the open-loop transfer function is a proportional-integral (PI) controller plus delay, meeting con-straints on the magnitude of the closed-loop transfer function and on the plant gain uncertainty. These two specifications are used to characterize the robustness, and are a recommended alternative to the gain and phase margin constraints. A control design plot is presented which allows for selection of controller parameters in-cluding those for the lowest sensitivity controller, and graphically highlights gain and phase margin tradeoffs. The paper discusses limitations of performance of such systems in terms of crossover frequency and sensitivity. In addition, expressions and design plots are provided for a simplified approximate solution.
