http://hdl.handle.net/2117/7275 Thu, 20 Jun 2013 00:18:56 GMT 2013-06-20T00:18:56Z webmaster.bupc@upc.edu Universitat Politècnica de Catalunya. Servei de Biblioteques i Documentació no http://hdl.handle.net/2117/18178 Title: Performance evaluation framework (PEF) for real-time embedded control systems Authors: Lozoya Gámez, Rafael Camilo; Martí Colom, Pau; Velasco García, Manel; Fuertes Armengol, José Mª Abstract: This report presents a performance evaluation framework (PEF) designed to simulate and implement diverse theoretical results on control and resource performance optimization that has recently appeared in the literature Mon, 11 Mar 2013 14:36:28 GMT http://hdl.handle.net/2117/18178 2013-03-11T14:36:28Z Lozoya Gámez, Rafael Camilo; Martí Colom, Pau; Velasco García, Manel; Fuertes Armengol, José Mª no This report presents a performance evaluation framework (PEF) designed to simulate and implement diverse theoretical results on control and resource performance optimization that has recently appeared in the literature http://hdl.handle.net/2117/18161 Title: Designing a practical course in networked control systems Authors: Fuertes Armengol, José Mª; Villa Millaruelo, Ricardo; Ayza Graells, Jordi; Marès Martí, Pere; Martí Colom, Pau; Velasco García, Manel; Yépez Castillo, José Gregorio; Torres Guerrero, Gina; Perelló, Miquel Abstract: This paper presents a hands-on course in networked control systems (NCS) to be integrated in the education of embedded control systems engineers. The course activities have a strong practical component and most of them are applied exercises to be implemented in a NCS setup. The paper describes the experimental setup and then proposes several activities that can be shaped into a course program according to the needs and diverse background of the targeted audience. Mon, 11 Mar 2013 07:52:51 GMT http://hdl.handle.net/2117/18161 2013-03-11T07:52:51Z Fuertes Armengol, José Mª; Villa Millaruelo, Ricardo; Ayza Graells, Jordi; Marès Martí, Pere; Martí Colom, Pau; Velasco García, Manel; Yépez Castillo, José Gregorio; Torres Guerrero, Gina; Perelló, Miquel no This paper presents a hands-on course in networked control systems (NCS) to be integrated in the education of embedded control systems engineers. The course activities have a strong practical component and most of them are applied exercises to be implemented in a NCS setup. The paper describes the experimental setup and then proposes several activities that can be shaped into a course program according to the needs and diverse background of the targeted audience. http://hdl.handle.net/2117/18144 Title: Design of a hands-on course in networked control systems Authors: Fuertes Armengol, José Mª; Villa Millaruelo, Ricardo; Ayza Graells, Jordi; Marès Martí, Pere; Martí Colom, Pau; Velasco García, Manel; Yépez Castillo, José Gregorio; Torres Guerrero, Gina Abstract: This report presents a hands-on course in networked control systems (NCS) to be integrated in the education of embedded control systems engineers. The course activities have a strong practical component and most of them are ap- plied exercises to be implemented in a NCS setup. The report containts four parts: a) a report that describes the experimental setup, proposing several activities that can be shaped into a course program according to the needs and diverse background of the targeted audience, b) a tentative program ex- ample for master students, c) a user manual to help setting up the hardware and software from a Live CD, and d) a quick guide to start working with the programming environment. Fri, 08 Mar 2013 11:03:59 GMT http://hdl.handle.net/2117/18144 2013-03-08T11:03:59Z Fuertes Armengol, José Mª; Villa Millaruelo, Ricardo; Ayza Graells, Jordi; Marès Martí, Pere; Martí Colom, Pau; Velasco García, Manel; Yépez Castillo, José Gregorio; Torres Guerrero, Gina no This report presents a hands-on course in networked control systems (NCS) to be integrated in the education of embedded control systems engineers. The course activities have a strong practical component and most of them are ap- plied exercises to be implemented in a NCS setup. The report containts four parts: a) a report that describes the experimental setup, proposing several activities that can be shaped into a course program according to the needs and diverse background of the targeted audience, b) a tentative program ex- ample for master students, c) a user manual to help setting up the hardware and software from a Live CD, and d) a quick guide to start working with the programming environment. http://hdl.handle.net/2117/17581 Title: Hands-on course in networked control systems Authors: Fuertes Armengol, José Mª; Villa Millaruelo, Ricardo; Ayza Graells, Jordi; Marès Martí, Pere; Martí Colom, Pau; Velasco García, Manel; Yepez, J.; Torres Guerrero, Gina; Perello, M. Abstract: In many industrial robotic applications there is a need to track periodic reference signals and/or reject periodic disturbances. This paper presents a novel repetitive control design for systems with constant time-delays in both forward and feedback control channels. An additional delay is introduced together with plant delays to construct an internal model for periodic signals, and a simple proportional control is utilized to stabilize the closed-loop system. Sufficient stability conditions of the closed-loop system and the robustness analysis under modeling uncertainties are studied. Experimental results are included to evaluate the validity and effectiveness of the proposed method. Tue, 05 Feb 2013 12:45:53 GMT http://hdl.handle.net/2117/17581 2013-02-05T12:45:53Z Fuertes Armengol, José Mª; Villa Millaruelo, Ricardo; Ayza Graells, Jordi; Marès Martí, Pere; Martí Colom, Pau; Velasco García, Manel; Yepez, J.; Torres Guerrero, Gina; Perello, M. no In many industrial robotic applications there is a need to track periodic reference signals and/or reject periodic disturbances. This paper presents a novel repetitive control design for systems with constant time-delays in both forward and feedback control channels. An additional delay is introduced together with plant delays to construct an internal model for periodic signals, and a simple proportional control is utilized to stabilize the closed-loop system. Sufficient stability conditions of the closed-loop system and the robustness analysis under modeling uncertainties are studied. Experimental results are included to evaluate the validity and effectiveness of the proposed method. http://hdl.handle.net/2117/17519 Title: Network-based control Authors: Fuertes Armengol, José Mª; Chow, Mo-Yuen; Villa Millaruelo, Ricardo; Gupta, Rachana; Ayza Graells, Jordi Fri, 25 Jan 2013 11:54:15 GMT http://hdl.handle.net/2117/17519 2013-01-25T11:54:15Z Fuertes Armengol, José Mª; Chow, Mo-Yuen; Villa Millaruelo, Ricardo; Gupta, Rachana; Ayza Graells, Jordi no http://hdl.handle.net/2117/14476 Title: Qualitative analysis of a one-step finite-horizon boundary for event-driven controllers Authors: Velasco García, Manel; Martí Colom, Pau; Yépez Castillo, José Gregorio; Ruiz Vegas, Francisco Javier; Fuertes Armengol, José Mª; Bini, Enrico Abstract: Performance optimization for networked and embedded control systems refers to the ability of minimizing controllers’ resource utilization and/or improving control performance. Event-driven control has been shown to be a promising technique for minimizing controllers’ computational demands. However, optimization of control performance for event-driven control has not been fully addressed. For LTI plants, this paper presents a boundary for event-driven controllers that determines at each job execution when the next job execution should occur in order to minimize a continuous-time quadratic cost function while minimizing controllers’ computational demand. Simulation results illustrate the qualitative shape of this boundary. Wed, 11 Jan 2012 16:16:36 GMT http://hdl.handle.net/2117/14476 2012-01-11T16:16:36Z Velasco García, Manel; Martí Colom, Pau; Yépez Castillo, José Gregorio; Ruiz Vegas, Francisco Javier; Fuertes Armengol, José Mª; Bini, Enrico no Performance optimization for networked and embedded control systems refers to the ability of minimizing controllers’ resource utilization and/or improving control performance. Event-driven control has been shown to be a promising technique for minimizing controllers’ computational demands. However, optimization of control performance for event-driven control has not been fully addressed. For LTI plants, this paper presents a boundary for event-driven controllers that determines at each job execution when the next job execution should occur in order to minimize a continuous-time quadratic cost function while minimizing controllers’ computational demand. Simulation results illustrate the qualitative shape of this boundary. http://hdl.handle.net/2117/14474 Title: Lowering traffic without sacrificing performance in networked control systems Authors: Martí Colom, Pau; Velasco García, Manel; Yépez Castillo, José Gregorio; Martín Rull, Enric Xavier Abstract: In Networked Control Systems (NCS), the amount of control data exchanged between sensors, controllers and actuators nodes highly depends on the control performance specifications given to each networked control loop. The periodic execution of each loop helps meeting the control specifications while imposing a static network traffic. This paper presents an alternative execution mechanism for each networked control loop that permits to dynamically lower the traffic while ensuring the same or better control performance than the achieved by the periodic case. Simulation results illustrate the theoretical analysis. Wed, 11 Jan 2012 15:23:48 GMT http://hdl.handle.net/2117/14474 2012-01-11T15:23:48Z Martí Colom, Pau; Velasco García, Manel; Yépez Castillo, José Gregorio; Martín Rull, Enric Xavier no In Networked Control Systems (NCS), the amount of control data exchanged between sensors, controllers and actuators nodes highly depends on the control performance specifications given to each networked control loop. The periodic execution of each loop helps meeting the control specifications while imposing a static network traffic. This paper presents an alternative execution mechanism for each networked control loop that permits to dynamically lower the traffic while ensuring the same or better control performance than the achieved by the periodic case. Simulation results illustrate the theoretical analysis. http://hdl.handle.net/2117/14473 Title: Networked sliding mode control of the double integrator system using the event-driven self-triggered approach Authors: Martí Colom, Pau; Velasco García, Manel; Camacho Santiago, Antonio; Martín Rull, Enric Xavier; Fuertes Armengol, José Mª Abstract: Sliding mode control (SMC) methods rely on applying a high-frequency switching control. In networked control systems (NCS), high-frequency operations/transactions are not desirable because communication bandwidth consumption increases dramatically. This paper studies the application of event-driven self-triggered techniques to sliding mode control over networks as a means for reducing the bandwidth utilization. To this end, sliding mode control with hysteresis is adopted and control updates are forced to only occur at the hysteresis band boundary. This paper elaborates on the conditions that must be fulfilled in order to ensure such operation for the case of the double integrator system. Simulation results illustrate the presented concepts. Wed, 11 Jan 2012 13:27:51 GMT http://hdl.handle.net/2117/14473 2012-01-11T13:27:51Z Martí Colom, Pau; Velasco García, Manel; Camacho Santiago, Antonio; Martín Rull, Enric Xavier; Fuertes Armengol, José Mª no Sliding mode control (SMC) methods rely on applying a high-frequency switching control. In networked control systems (NCS), high-frequency operations/transactions are not desirable because communication bandwidth consumption increases dramatically. This paper studies the application of event-driven self-triggered techniques to sliding mode control over networks as a means for reducing the bandwidth utilization. To this end, sliding mode control with hysteresis is adopted and control updates are forced to only occur at the hysteresis band boundary. This paper elaborates on the conditions that must be fulfilled in order to ensure such operation for the case of the double integrator system. Simulation results illustrate the presented concepts. http://hdl.handle.net/2117/14313 Title: Design of an embedded control system laboratory experiment Authors: Martí Colom, Pau; Velasco García, Manel; Fuertes Armengol, José Mª; Camacho Santiago, Antonio; Buttazzo, Giorgio Abstract: This paper presents a prototype laboratory experiment to be integrated in the education of embedded control system engineers. The experiment, a real-time control of a dynamical system, is designed to drive students to a deeper understanding and integration of the diverse theoretical concepts that often come from different disciplines such as real-time systems and control systems. Rather than proposing the experiment for a particular course within an embedded system engineering curriculum, this paper describes how the experiment can be tailored to the needs and diverse background of both undergraduate and graduate students education. Thu, 22 Dec 2011 13:08:12 GMT http://hdl.handle.net/2117/14313 2011-12-22T13:08:12Z Martí Colom, Pau; Velasco García, Manel; Fuertes Armengol, José Mª; Camacho Santiago, Antonio; Buttazzo, Giorgio no This paper presents a prototype laboratory experiment to be integrated in the education of embedded control system engineers. The experiment, a real-time control of a dynamical system, is designed to drive students to a deeper understanding and integration of the diverse theoretical concepts that often come from different disciplines such as real-time systems and control systems. Rather than proposing the experiment for a particular course within an embedded system engineering curriculum, this paper describes how the experiment can be tailored to the needs and diverse background of both undergraduate and graduate students education. http://hdl.handle.net/2117/14053 Title: Efficient utilization of bus idle times in CAN-based networked control systems Authors: Martí Colom, Pau; Camacho Santiago, Antonio; Velasco García, Manel; El Mongi Ben Gaid, Mohamed Abstract: This paper presents a novel approach to networked control systems (NCS) analysis and design that provides increased control performance for a set of control loops that exchange control data over the Controller Area Network (CAN). This is achieved by enabling the following functionality for each control loop: first, standard periodic messaging is guaranteed to ensure stability, and second, non-periodic additional messaging is added whenever the bus is idle in such a way that the aggregated control performance for all control loops is improved. The proposed approach, named Maximum Difference (MD) policy, is computable in a distributed manner, and is practically feasible (computationally efficient and CAN-implementable). We theoretically prove that the MD policy behaves better than static strategies. Simulation results complement the theoretical derivations and show that the MD policy outperforms static, random and Largest Error First policies. Thu, 24 Nov 2011 10:52:13 GMT http://hdl.handle.net/2117/14053 2011-11-24T10:52:13Z Martí Colom, Pau; Camacho Santiago, Antonio; Velasco García, Manel; El Mongi Ben Gaid, Mohamed no This paper presents a novel approach to networked control systems (NCS) analysis and design that provides increased control performance for a set of control loops that exchange control data over the Controller Area Network (CAN). This is achieved by enabling the following functionality for each control loop: first, standard periodic messaging is guaranteed to ensure stability, and second, non-periodic additional messaging is added whenever the bus is idle in such a way that the aggregated control performance for all control loops is improved. The proposed approach, named Maximum Difference (MD) policy, is computable in a distributed manner, and is practically feasible (computationally efficient and CAN-implementable). We theoretically prove that the MD policy behaves better than static strategies. Simulation results complement the theoretical derivations and show that the MD policy outperforms static, random and Largest Error First policies. http://hdl.handle.net/2117/13963 Title: One-step finite horizon boundary with varying control gain for event-driven networked control systems Authors: Yépez Castillo, José Gregorio; Velasco García, Manel; Martí Colom, Pau; Martín, Enric Xavier; Fuertes Armengol, José Mª Abstract: Recent research has shown that event-driven control requires less samples than time-driven (periodic) control. Consequently, event-driven control applied to Networked Control Systems (NCS) is a good approach for alleviating controllers bandwidth demands and reducing overall network traffic. Following this trend, this paper presents an execution rule for event-driven networked controllers that at each job execution aims at postponing the next job execution while applying an appropriated controller gain considering each varying sampling interval that applies at run time. This method permits to dynamically lower the generated traffic for each networked control loop while ensuring the same or better control performance than the achieved by the periodic case. In addition, an implementation strategy capable of dealing with network induced time delays is also presented. Simulation results illustrate the operation and benefits of the presented approach. Fri, 18 Nov 2011 12:36:24 GMT http://hdl.handle.net/2117/13963 2011-11-18T12:36:24Z Yépez Castillo, José Gregorio; Velasco García, Manel; Martí Colom, Pau; Martín, Enric Xavier; Fuertes Armengol, José Mª no Recent research has shown that event-driven control requires less samples than time-driven (periodic) control. Consequently, event-driven control applied to Networked Control Systems (NCS) is a good approach for alleviating controllers bandwidth demands and reducing overall network traffic. Following this trend, this paper presents an execution rule for event-driven networked controllers that at each job execution aims at postponing the next job execution while applying an appropriated controller gain considering each varying sampling interval that applies at run time. This method permits to dynamically lower the generated traffic for each networked control loop while ensuring the same or better control performance than the achieved by the periodic case. In addition, an implementation strategy capable of dealing with network induced time delays is also presented. Simulation results illustrate the operation and benefits of the presented approach. http://hdl.handle.net/2117/12293 Title: Synchronizing sampling and actuation in the absence of global time in networked control systems Authors: Martí Colom, Pau; Camacho Santiago, Antonio; Velasco García, Manel; Marès Martí, Pere; Fuertes Armengol, José Mª Abstract: The successful operation of Networked Control Sys- tems (NCS) requires employing appropriate approaches for dealing with network induced time delays, i.e. time intervals elapsed from consecutive sampling and actua- tion operations. Effective approaches often require to im- pose periodic execution for the sampling and/or actuation operations, enforcing synchronized constant time delays. And considering that sampling and actuation is performed in different nodes, global time between nodes achieved by clock synchronization is the standard assumption or strat- egy that enables such synchronized operations. This pa- per presents a technique that permits to implement these synchronized operations in NCS in the absence of global time. Experimental results corroborate the effectiveness of the presented approach. Thu, 07 Apr 2011 10:17:40 GMT http://hdl.handle.net/2117/12293 2011-04-07T10:17:40Z Martí Colom, Pau; Camacho Santiago, Antonio; Velasco García, Manel; Marès Martí, Pere; Fuertes Armengol, José Mª no The successful operation of Networked Control Sys- tems (NCS) requires employing appropriate approaches for dealing with network induced time delays, i.e. time intervals elapsed from consecutive sampling and actua- tion operations. Effective approaches often require to im- pose periodic execution for the sampling and/or actuation operations, enforcing synchronized constant time delays. And considering that sampling and actuation is performed in different nodes, global time between nodes achieved by clock synchronization is the standard assumption or strat- egy that enables such synchronized operations. This pa- per presents a technique that permits to implement these synchronized operations in NCS in the absence of global time. Experimental results corroborate the effectiveness of the presented approach. http://hdl.handle.net/2117/10676 Title: Invariant manifolds as boundaries for event-driven control systems Authors: Velasco García, Manel; Martí Colom, Pau Abstract: In event-driven control approaches, control updates are triggered by event conditions that are often characterized by different types of boundaries defined in the state-space domain. In this paper we define an event-driven control approach where boundaries are manifolds characterized as invariant sets. With such a boundary, a control update will only be activated when the system trajectory intersects the boundary. And the system trajectory must intersect again the boundary to activate the next control update. For linear systems, we derive an scaling property for these boundaries that permit to regulate the accuracy of the control without altering the timing offered by the scaled boundary. Mon, 20 Dec 2010 10:14:58 GMT http://hdl.handle.net/2117/10676 2010-12-20T10:14:58Z Velasco García, Manel; Martí Colom, Pau no In event-driven control approaches, control updates are triggered by event conditions that are often characterized by different types of boundaries defined in the state-space domain. In this paper we define an event-driven control approach where boundaries are manifolds characterized as invariant sets. With such a boundary, a control update will only be activated when the system trajectory intersects the boundary. And the system trajectory must intersect again the boundary to activate the next control update. For linear systems, we derive an scaling property for these boundaries that permit to regulate the accuracy of the control without altering the timing offered by the scaled boundary. http://hdl.handle.net/2117/10314 Title: Simulation study of a remote wireless path tracking control with delay estimation for an autonomous guided vehicle Authors: Lozoya, Camilo; Martí Colom, Pau; Velasco García, Manel; Fuertes Armengol, José Mª; Martín Rull, Enric Xavier Abstract: Industrial applications involving mobile systems can benefit from the use of wireless technology. However, wireless communication has not been widely accepted on the factory floor due to its difficulty in achieving the timely and reliable transmission of messages over error-prone wireless channels. This paper presents an autonomous guided vehicle (AGV) path tracking wireless control system where an accurate delay estimation scheme is shown to be the key for successful operation. The control architecture consists on an AGV connected through a wireless network to a controller. To mitigate the negative effects that varying time delays in data transfer have in the networked control loop, the controller performs two tasks at each loop operation. First, it uses a Kalman filter to produce an optimal delay estimate considering a simple stochastic model of the wireless delay dynamics. Second, each delay estimate is employed to infer the real AGV position which permits to compute the appropriate control commands. Results show that the proposed technique provides more efficient and effective operation for path tracking control compared to similar previously proposed solutions. Tue, 16 Nov 2010 13:11:05 GMT http://hdl.handle.net/2117/10314 2010-11-16T13:11:05Z Lozoya, Camilo; Martí Colom, Pau; Velasco García, Manel; Fuertes Armengol, José Mª; Martín Rull, Enric Xavier no Industrial applications involving mobile systems can benefit from the use of wireless technology. However, wireless communication has not been widely accepted on the factory floor due to its difficulty in achieving the timely and reliable transmission of messages over error-prone wireless channels. This paper presents an autonomous guided vehicle (AGV) path tracking wireless control system where an accurate delay estimation scheme is shown to be the key for successful operation. The control architecture consists on an AGV connected through a wireless network to a controller. To mitigate the negative effects that varying time delays in data transfer have in the networked control loop, the controller performs two tasks at each loop operation. First, it uses a Kalman filter to produce an optimal delay estimate considering a simple stochastic model of the wireless delay dynamics. Second, each delay estimate is employed to infer the real AGV position which permits to compute the appropriate control commands. Results show that the proposed technique provides more efficient and effective operation for path tracking control compared to similar previously proposed solutions. http://hdl.handle.net/2117/9966 Title: Self-triggered networked control systems: an experimental case study Authors: Camacho Santiago, Antonio; Martí Colom, Pau; Velasco García, Manel; Lozoya, Camilo; Villa Millaruelo, Ricardo; Fuertes Armengol, José Mª; Griful Ponsati, Eulàlia Abstract: A self-triggered controller is characterized, in general, by a non-periodic sequence of job activations. And each job execution, apart from performing sampling, control algorithm computation and actuation, calculates the next job activation time as a function of the plant state. This paper describes the implementation of self-triggered controllers in networked control systems (NCS). The implementation corroborates that self-triggered control can be used for minimizing bandwidth utilization while providing similar control performance than periodic controllers. Mon, 25 Oct 2010 12:06:15 GMT http://hdl.handle.net/2117/9966 2010-10-25T12:06:15Z Camacho Santiago, Antonio; Martí Colom, Pau; Velasco García, Manel; Lozoya, Camilo; Villa Millaruelo, Ricardo; Fuertes Armengol, José Mª; Griful Ponsati, Eulàlia no A self-triggered controller is characterized, in general, by a non-periodic sequence of job activations. And each job execution, apart from performing sampling, control algorithm computation and actuation, calculates the next job activation time as a function of the plant state. This paper describes the implementation of self-triggered controllers in networked control systems (NCS). The implementation corroborates that self-triggered control can be used for minimizing bandwidth utilization while providing similar control performance than periodic controllers.