| 1. |
- Forsman, Krister
(författare)
-
Hybrid Control Systems and Comprehensive Gröbner Bases
- 1994
-
Ingår i: Proceedings of the 33rd IEEE Conference on Decision and Control. - Linköping : Linköping University. - 0780319680 ; , s. 4092-4097 vol.4
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- A class of hybrid systems that can be modeled by polynomial differential equations is investigated. By a hybrid system we mean a system which mixes continuous and discrete variables. All variables in the system have the same time scale. The polynomial models have the advantage that constructive methods are available for system analysis. One such method that occurs naturally in this context is so called comprehensive Grobner bases
|
|
| 2. |
- Forsman, Krister, et al.
(författare)
-
Input-Output Equations and Observability for Polynomial Delay Systems
- 1994
-
Ingår i: Proceedings of the 33rd IEEE Conference on Decision and Control. - Linköping : Linköping University. - 0780319680 ; , s. 880-882 vol.1
-
Konferensbidrag (refereegranskat)abstract
- This paper discusses and strengthens a result by Fliess (1988) about input-output equations for polynomial systems with time delays. The proof given is more detailed and it opens the way for constructive methods for determining the input-output behavior. A method based on Grobner's approach is described in detail. Furthermore, some connections with observability are exploited.
|
|
| 3. |
- Forsman, Krister
(författare)
-
On Nonlinear Systems with Linear Dynamics
- 1994
-
Ingår i: Proceedings of the 33rd IEEE Conference on Decision and Control. - Linköping : Linköping University. - 0780319680 ; , s. 1778-1783 vol.2
-
Konferensbidrag (refereegranskat)abstract
- Some classes of polynomial control systems are investigated and characterized in terms of their input-output behavior. The first class are those that can be realized as a set of linear state equations with a polynomial output map. The second class are those that can be realized as a set of homogeneous (w.r.t. some grading) state equations with homogeneous output map.
|
|
| 4. |
- Forsman, Krister, et al.
(författare)
-
Some Finiteness Issues in Differential Algebraic Systems Theory
- 1994
-
Ingår i: Proceedings of the 33rd IEEE Conference on Decision and Control. - Linköping : Linköping University. - 0780319680 ; , s. 1112-1117 vol.2
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The elimination problem in differential algebraic systems theory is discussed. The focus is on finiteness questions, such as conditions for the elimination ideal to be finitely generated.
|
|
| 5. |
- Fortell, Håkan
(författare)
-
Calculation of Zero Dynamics using the Ritt Algorithm
- 1994
-
Ingår i: Proceedings of the 33rd IEEE Conference on Decision and Control. - 0780319680 ; , s. 3271-3276 vol.4
-
Konferensbidrag (refereegranskat)abstract
- This paper shows how differential algebra, in particular the Ritt algorithm, can be used to calculate zero dynamics of a polynomial system. We show that for affine polynomial SISO systems the Ritt algorithm gives a result which is equivalent to the ordinary zero dynamics. Furthermore it is shown how the algorithm can be used to calculate zero dynamics for more general affine systems. We also discuss zero dynamics of generalized state-space descriptions.
|
|
| 6. |
- Fortell, Håkan
(författare)
-
On Zeros of Regular Transfer Functions and the Zero Dynamics
- 1994
-
Ingår i: Proceedings of the 33rd IEEE Conference on Decision and Control. - 0780319680 ; , s. 3265-3270 vol.4
-
Konferensbidrag (refereegranskat)abstract
- This paper considers zeros of regular transfer function sequences of nonlinear systems and if there is a relationship between these zeros and the zero dynamics. Such a relationship is found to exist if the numerators of the regular transfer functions can be factored in a certain way. The zero dynamics is then seen to contain a purely linear part whose eigenvalues exactly correspond to the zeros of the above mentioned factorization.
|
|
| 7. |
- Guo, Lei, et al.
(författare)
-
Performance Analysis of General Tracking Algorithms
- 1994
-
Ingår i: Proceedings of the 33rd IEEE Conference on Decision and Control. - Linköping : Linköping University. - 0780319680 ; , s. 2851-2855 vol.3
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- A general family of tracking algorithms for linear regression models is studied. It includes the familiar LMS (gradient approach), RLS (recursive least squares) and KF (Kalman filter) based estimators. The exact expressions for the quality of the obtained estimates are complicated. Approximate, and easy-to-use, expressions for the covariance matrix of the parameter tracking error are developed. These are applicable over whole time interval, including the transient and the approximation error can be explicitly calculated.
|
|
| 8. |
- Helmersson, Anders, 1957-
(författare)
-
Model Reduction using LMIs
- 1994
-
Ingår i: Proceedings of the 33rd IEEE Conference on Decision and Control. - Linköping : Linköping University. - 0780319680 ; , s. 3217-3222 vol.4
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This paper treats the problem of approximating an nth order continuous system by a system of order k∞ norm of the approximation error exist for k=0, n-1. This paper presents an iterative two-step LMI method for improving the H∞ model error compared to Hankel norm reduction.
|
|
| 9. |
- Hjalmarsson, Håkan, 1962-, et al.
(författare)
-
Convergent iterative restricted complexity control design scheme
- 1994
-
Ingår i: Proceedings of the IEEE Conference on Decision and Control. - Lake Buena Vista, FL, USA : Linköping University. - 0780319680 ; , s. 1735-1740
-
Konferensbidrag (refereegranskat)abstract
- In this contribution we propose an optimization approach to the design of a restricted complexity controller. The design criterion is of LQG type containing two terms. The first term is the quadratic norm of the error between the output of the true closed loop and a desired response. The second term is the quadratic norm of the input signals. It is shown that the minimization of this criterion does not require a model of the system. Closed loop experimental data can be used instead. The result is an iterative scheme of closed loop experiments and controller updates which converges to a local minimum of the design criterion under the condition of bounded signals.
|
|
| 10. |
- Hjalmarsson, Hakan, 1962-, et al.
(författare)
-
Identification for control: closing the loop gives more accurate controllers
- 1994
-
Ingår i: Proceedings of the IEEE Conference on Decision and Control. - Lake Buena Vista, FL, USA. - 0780319680 ; , s. 4150-4155
-
Konferensbidrag (refereegranskat)abstract
- We compare open loop versus closed loop identification when the identified model is used for control design, and when the system itself belongs to the model class, so that only variance errors are relevant. For three different control design criteria (minimum variance, LQG and model) reference control) we show that, under those conditions, a better performance is achieved by closing the loop during the identification. The measure of performance is the variance of the error between the output of the ideal closed loop system (with the ideal controller) and that of the actual closed loop system (with the controller computed from the identified model).
|
|
