| 1. |
- Andreasson, Martin, et al.
(författare)
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Distributed integral action : stability analysis and frequency control of power systems
- 2012
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Ingår i: 2012 IEEE 51st Annual Conference on Decision and Control (CDC). - : IEEE. - 9781467320665 ; , s. 2077-2083
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Konferensbidrag (refereegranskat)abstract
- This paper analyzes distributed proportional-integral controllers. We prove that integral action can be successfully applied to consensus algorithms, where attenuation of static disturbances is achieved. These control algorithms are applied to decentralized frequency control of electrical power systems. We show that the proposed algorithm can attenuate step disturbances of power loads. We provide simulations of the proposed control algorithm on the IEEE 30 bus test system that demonstrate its efficiency.
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| 2. |
- Annergren, Mariette, et al.
(författare)
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An ADMM Algorithm for Solving l(1) Regularized MPC
- 2012
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Ingår i: 2012 IEEE 51st Annual Conference on Decision and Control (CDC). - : IEEE. - 9781467320665 ; , s. 4486-4491
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Konferensbidrag (refereegranskat)abstract
- We present an Alternating Direction Method of Multipliers (ADMM) algorithm for solving optimization problems with an ℓ1 regularized least-squares cost function subject to recursive equality constraints. The considered optimization problem has applications in control, for example in ℓ1 regularized MPC. The ADMM algorithm is easy to implement, converges fast to a solution of moderate accuracy, and enables separation of the optimization problem into sub-problems that may be solved in parallel. We show that the most costly step of the proposed ADMM algorithm is equivalent to solving an LQ regulator problem with an extra linear term in the cost function, a problem that can be solved efficiently using a Riccati recursion. We apply the ADMM algorithm to an example of ℓ1 regularized MPC. The numerical examples confirm fast convergence to sufficient accuracy and a linear complexity in the MPC prediction horizon.
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| 3. |
- Farokhi, Farhad, 1987-, et al.
(författare)
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Limited Model Information Control Design for Linear Discrete-Time Systems with Stochastic Parameters
- 2012
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Ingår i: 2012 IEEE 51st Annual Conference on Decision And Control (CDC). - : IEEE. - 9781467320665 ; , s. 855-861
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Konferensbidrag (refereegranskat)abstract
- We design optimal local controllers for large-scale networked systems using exact local model information and statistical beliefs about the model of the rest of the system. We study the value of model information in control design using the closed-loop performance degradation caused by the lack of full model information in the control design procedure. This performance degradation is captured using the ratio of the cost of the optimal controller with limited model information over the cost of the optimal controller with full model information. Both finite-horizon and infinite-horizon cost functions are considered. A numerical example illustrates the developed approach.
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| 4. |
- Feyzmahdavian, Hamid Reza, et al.
(författare)
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Optimal Distributed Controller Design with Communication Delays : Application to vehicle formations
- 2012
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Ingår i: 2012 IEEE 51st Annual Conference on Decision and Control (CDC). - : IEEE conference proceedings. - 9781467320665 ; , s. 2232-2237
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Konferensbidrag (refereegranskat)abstract
- We consider the problem of optimal distributed control with delayed information sharing over chain structures motivated by applications of heavy duty vehicle platooning. We introduce a novel approach to find distributed controllers that take into account communication delays and correlation between the dynamic interconnection. The design decomposes the solution into separate optimization problems. The results show that a tight control is achieved, even in the presence of delays, and behaves well with respect to the imposed disturbances. The computed theoretical cost of the proposed optimal controller is significantly better than the theoretical cost for the centralized control with a global delay and close to the cost for a fully centralized control with full state information at all times.
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| 5. |
- Huang, Lirong, et al.
(författare)
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Adaptive experiment design for ARMAX systems?
- 2012
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Ingår i: 2012 IEEE 51st Annual Conference on Decision and Control (CDC). - : IEEE. - 9781467320665 ; , s. 907-912
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Konferensbidrag (refereegranskat)abstract
- A key problem in optimal input design is that the optimal input depends on some unknown system parameters that are to be identified. Adaptive design is one of the fundamental routes to handle this problem. This paper proposes an adaptive input design method for ARMAX systems based on the general stochastic framework outlined in the reference [10].
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| 6. |
- Karayiannidis, Yiannis, 1980-, et al.
(författare)
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Multi-agent average consensus control with prescribed performance guarantees
- 2012
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Ingår i: 2012 IEEE 51st Annual Conference on Decision and Control (CDC). - : IEEE. - 9781467320665 ; , s. 2219-2225
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Konferensbidrag (refereegranskat)abstract
- This work proposes a distributed control scheme for the state agreement problem which can guarantee prescribed performance for the system transient. In particular, i) we consider a set of agents that can exchange information according to a static communication graph, ii) we a priori define time-dependent constraints at the edge's space (errors between agents that exchange information) and iii) we design a distributed controller to guarantee that the errors between the neighboring agents do not violate the constraints. Following this technique the contributions are twofold: a) the convergence rate of the system and the communication structure of the agents' network which are strictly connected can be decoupled, and b) the connectivity properties of the initially formed communication graph are rendered invariant by appropriately designing the prescribed performance bounds. It is also shown how the structure and the parameters of the prescribed performance controller can be chosen in case of connected tree graphs and connected graphs with cycles. Simulation results validate the theoretically proven findings while enlightening the merit of the proposed prescribed performance agreement protocol as compared to the linear one.
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| 7. |
- Katselis, Dimitrios, et al.
(författare)
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A Chernoff relaxation on the problem of application-oriented finite sample experiment design
- 2012
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Ingår i: 2012 IEEE 51st Annual Conference on Decision and Control (CDC). - : IEEE. - 9781467320665 ; , s. 202-207
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Konferensbidrag (refereegranskat)abstract
- In this paper, application-oriented experiment design formulated as a chance constrained problem is investigated. The chance constraint is based on the presumption that the estimated model can be used in an application to achieve a given performance level with a prescribed probability. The aforementioned performance level is dictated by the particular application of interest. The resulting optimization problem is known to be nonconvex in most cases. To this end, convexification is attempted by employing a Chernoff relaxation. As an application, we focus on the identification of multiple input multiple output (MIMO) wireless channel models based on a general L-optimality type of performance measure.
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| 8. |
- Markdahl, Johan, et al.
(författare)
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Exact solutions to the closed loop kinematics of an almost globally stabilizing feedback law on SO(3)
- 2012
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Ingår i: 2012 IEEE 51st Annual Conference on Decision and Control (CDC). - : IEEE. - 9781467320665 ; , s. 2274-2279
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Konferensbidrag (refereegranskat)abstract
- We propose a kinematic control law that solves the problem of stabilizing the attitude of a fully actuated rigid body to a desired rest attitude. The control law is designed on the special orthogonal group SO(3), thereby avoiding complications due to the representational singularities of local parametrizations and the unwinding phenomenon associated with global many-to-one parametrizations. We prove almost global stability, i.e. asymptotical stability from all initial conditions except for a set of zero measure. The proposed control law decouples the closed loop kinematics, allowing us to solve the state equations exactly for the rigid body attitude as a function of time, the initial conditions, and two gain parameters. The exact solutions provide an understanding of the transient behaviour of the system and can e.g. be used to tune the gain parameters. The geometric flavor of these ideas is illustrated by simulation.
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| 9. |
- Sandberg, Henrik
(författare)
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Parameterized model order reduction using extended balanced truncation
- 2012
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Ingår i: 2012 IEEE 51st Annual Conference On Decision And Control (CDC). - : IEEE. - 9781467320665 ; , s. 4291-4296
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Konferensbidrag (refereegranskat)abstract
- We show how extended balanced truncation can be applied to the parameterized model order reduction (PMOR) problem. Two variants are introduced and are shown to improve already available a priori error bounds, as well as actual approximation errors in a numerical experiment.
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| 10. |
- Simonetto, Andrea, et al.
(författare)
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A Regularized Saddle-Point Algorithm for Networked Optimization with Resource Allocation Constraints
- 2012
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Ingår i: 2012 IEEE 51ST ANNUAL CONFERENCE ON DECISION AND CONTROL (CDC). - : IEEE. - 9781467320665 ; , s. 7476-7481
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Konferensbidrag (refereegranskat)abstract
- We propose a regularized saddle-point algorithm for convex networked optimization problems with resource allocation constraints. Standard distributed gradient methods suffer from slow convergence and require excessive communication when applied to problems of this type. Our approach offers an alternative way to address these problems, and ensures that each iterative update step satisfies the resource allocation constraints. We derive step-size conditions under which the distributed algorithm converges geometrically to the regularized optimal value, and show how these conditions are affected by the underlying network topology. We illustrate our method on a robotic network application example where a group of mobile agents strive to maintain a moving target in the barycenter of their positions.
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| 11. |
- Wahlberg, Bo, et al.
(författare)
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On asymptotic frequency response variance expressions for estimated output error models
- 2012
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Ingår i: 2012 IEEE 51st Annual Conference on Decision and Control (CDC). - : IEEE. - 9781467320665 ; , s. 178-183
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Konferensbidrag (refereegranskat)abstract
- This papers concerns an extension of an asymptotic variance expression for Finite Impulse Response (FIR) model based frequency response estimation to the Output Error (OE) system identification case. It is based on the 'useful input parametrization' for OE models, in which the Toeplitz covariance matrix structure instrumental in the FIR analysis is extended to OE model input representation after a Sylvester matrix transformation. We will use this result to derive a novel and transparent variance expression for the asymptotic OE frequency response estimate. This results simplifies the generalization of FIR results for optimal input design and cost of complexity system identification analysis to the OE case. Furthermore, the relation to previous exact variance error quantifications is explained.
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| 12. |
- Wang, Yuquan, et al.
(författare)
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A transformation of the Position Based Visual Servoing Problem into a convex optimization problem
- 2012
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Ingår i: 2012 IEEE 51st Annual Conference on Decision and Control (CDC). - : IEEE. - 9781467320665 ; , s. 5673-5678
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Konferensbidrag (refereegranskat)abstract
- Here we address the problem of moving a camera from an initial pose to a final pose. The trajectory between the two poses is subject to constraints on the camera motion and the visibility, where we have bounds on the allowed velocities and accelerations of the camera and require that a set of point features are visible for the camera. We assume that the pose is possible to retrieve from the observations of the point features, i.e., we have a Position Based Visual Servoing Problem with constraints. We introduce a two step method that transforms the problem into a convex optimization problem with linear constraints. In the first step the rotational motion is restricted to be of a certain type. This restriction allows us to retrieve an explicit solution of the rotational motion that is optimal in terms of minimizing geodesic distance. Furthermore, this restriction guarantees that the rotational motion satisfies the constraints. Using the explicit solution, we can formulate a convex optimization problem for the translational motion, where we include constraints on workspace and visibility.
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| 13. |
- Yang, Tao, et al.
(författare)
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Semi-global regulation of output synchronization for heterogeneous networks of non-introspective, invertible agents subject to actuator saturation
- 2012
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Ingår i: 2012 IEEE 51st Annual Conference on Decision and Control (CDC). - : IEEE. - 9781467320665 ; , s. 5298-5303
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Konferensbidrag (refereegranskat)abstract
- In this paper, we consider the semi-global regulation of output synchronization problem for heterogeneous networks of invertible linear agents subject to actuator saturation. That is, we regulate the output of each agent according to an a priori specified reference model. The network communication infrastructure provides each agent with a linear combination of its own output relative to that of neighboring agents, and it allows the agents to exchange information about their own internal observer estimates, while some agents have access to their own outputs relative to the reference trajectory.
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| 14. |
- Yang, Yuecheng, et al.
(författare)
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Opinion consensus of modified Hegselmann-Krause models
- 2012
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Ingår i: 2012 IEEE 51st Annual Conference on Decision and Control (CDC). - : IEEE. - 9781467320665 ; , s. 100-105
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Konferensbidrag (refereegranskat)abstract
- We consider the opinion consensus problem using a multi-agent setting based on the Hegselmann-Krause (H-K) Model. Firstly, we give a sufficient condition on the initial opinion distribution so that the system will converge to only one cluster. Then, modified models are proposed to guarantee convergence for more general initial conditions. The overall connectivity is maintained with these models, while the loss of certain edges can occur. Furthermore, a smooth control protocol is provided to avoid the difficulties that may arise due to the discontinuous right-hand side in the H-K model.
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| 15. |
- Zou, Zhenhua, et al.
(författare)
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Minimum-energy packet forwarding policies for guaranteed LQG performance in wireless control systems
- 2012
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Ingår i: 2012 IEEE 51st Annual Conference on Decision and Control (CDC). - : IEEE. - 9781467320665 ; , s. 3341-3346
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Konferensbidrag (refereegranskat)abstract
- This paper studies minimum-energy packet forwarding policies for communicating sensor measurements from plant to controller over an unreliable multi-hop wireless network so as to guarantee that the optimal controller achieves a prespecified closed-loop performance. For fixed sampling interval, we demonstrate that the minimal linear-quadratic control loss is monotonically decreasing in the reliability of the sensor-to-controller communication. This allows us to decompose the overall design problem into two separate tasks: finding the minimum end-to-end reliability that allows to achieve a prespecified linear-quadratic loss, and developing minimum-energy packet forwarding policies under a deadline-constrained reliability requirement. We develop optimal solutions for both subproblems and show how the co-designed system with minimum forwarding energy cost and guaranteed LQG control performance can be found by a one-dimensional search over admissible sampling periods. The paper ends with a numerical example which demonstrates the effectiveness of the proposed framework.
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