A novel event-triggered transmission scheme and L2 control co-design for sampled-data control systems

This note is concerned with the event-triggered L2 control for a sampled-data control system. A novel event-triggered transmission scheme is first proposed to determine whether or not the sampled-data should be transmitted. Under this scheme, the sampled-data transmission should be executed only when a threshold is violated, which means that less sampled-data is transmitted. This scheme does not require any special hardware for continuous measurement. Then, the sampled-data control system is modeled as a sampled-data error dependent system. A stability criterion is derived by constructing a novel Lyapunov-Krasovskii functional which fully utilizes the sawtooth structure characteristic of an artificial delay. Based on this stability criterion, a sufficient condition on the existence of a state feedback controller is given. A co-design algorithm is provided to obtain the parameters of the event-triggered transmission scheme and the controller gain simultaneously. Finally, an inverted pendulum example is given to show the effectiveness of the event-triggered transmission scheme and the co-design algorithm

Output-based event-triggered control for sampled-data control systems with non-uniform sampling

This paper is concerned with the event-triggered output feedback H ∞ control for sampled-data control systems with nonuniform sampling. Firstly, an output-based event-triggered communication scheme is proposed, in which the state of the system is sampled with a nonuniform sampling period. Under this scheme, whether or not the sampled data should be transmitted is determined by a predetermined output-based event-triggering condition. Secondly, an event-triggered networked control system is modeled as a time-delay system by taking into consideration the output-error between the output at the current sampling instant and the output at the last transmitted sampling instant. Thirdly, stability and stabilization criteria are derived to guarantee the uniform ultimate bounded stability and the desired performance while using less communication resources. Finally, two illustrative examples are used to show the effectiveness of the proposed method

A novel self-triggered sampling scheme in networked control systems

This paper proposes a novel self-triggered sampling scheme for the execution of sampling in networked control systems by taking into consideration network-induced delays and data packet dropouts. Using this scheme, the next sampling period is dynamically obtained with respect to (a) the desired performance; (b) the latest accepted time-stamped control packet; and (c) the allowable communication delay and the maximum allowable number of successive data dropouts. This scheme can adaptively adjust the sampling period to reduce communication loads with maintaining the desired control performance. Compared with some existing ones, this scheme does not require continuous measurement of the system state and on-line estimation of a triggering condition. An inverted pendulum is employed to demonstrate the effectiveness of the proposed scheme

Delay-range-dependent robust stabilization for uncertain T-S fuzzy control systems with interval time-varying delays

This paper is concerned with robust stabilization for a class of T-S fuzzy control systems with interval time-varying delays. An approach is proposed to significantly improve the system performance while reducing the number of scalar decision variables in linear matrix inequalities. The main points of the approach are: (i) two coupling integral inequalities are proposed to deal with some integral items in the derivation of the stability criteria; (ii) an appropriate Lyapunov-Krasovskii functional is constructed by including both the lower and upper bounds of the interval time-varying delays; and (iii) neither model transformation nor free weighting matrices are employed in the theoretical result derivation. As a result, some improved sufficient stability criteria are derived, and the maximum allowable delay bound and controller gains can be obtained simultaneously by solving an optimization problem. Numerical examples are given to demonstrate the effectiveness of the proposed approach

A novel self-triggered sampling scheme in networked control systems

This paper proposes a novel self-triggered sampling scheme for the execution of sampling in networked control systems by taking into consideration network-induced delays and data packet dropouts. Using this scheme, the next sampling period is dynamically obtained with respect to (a) the desired performance; (b) the latest accepted time-stamped control packet; and (c) the allowable communication delay and the maximum allowable number of successive data dropouts. This scheme can adaptively adjust the sampling period to reduce communication loads with maintaining the desired control performance. Compared with some existing ones, this scheme does not require continuous measurement of the system state and on-line estimation of a triggering condition. An inverted pendulum is employed to demonstrate the effectiveness of the proposed scheme

A discrete event-triggered communication scheme for networked T-S fuzzy systems

This paper presents a discrete event-triggered communication scheme for a class of networked Takagi-Sugeno (T-S) fuzzy systems. This scheme has two main features: i) whether or not the sampled state should be transmitted is determined by the current sampled state and the error between the current sampled state and the latest transmitted state, and ii) it is a discrete event-triggered communication scheme since the triggered conditions are measured and checked at the discrete sampling instant. Next, an asynchronous networked T-S fuzzy model is delicately constructed, which not only includes the state error, but also considers the non-uniform time scales in the networked T-S fuzzy model and the parallel distributed compensation fuzzy control rules. Then, using the Lyapunov-Krasovskii functional techniques, two sufficient conditions are derived for system analysis and synthesis, respectively. In particular, the derived stabilization criterion can provide a tradeoff to balance the required communication resources and the desired performance. Finally, a numerical example is given to show the effectiveness of the proposed method. © 2011 IEEE

Event-triggered quantized-data feedback control for linear systems

This paper proposes an event-triggered quantized-data feedback control scheme for linear systems. An event-triggered communication scheme is introduced to select which sampled-data should be quantized and transmitted to the controller. The threshold is constructed by considering the difference between the current sampled data and the latest quantized data. A finite-level dynamical quantizer is developed based on the communication scheme and quantized data. An output feedback controller is designed to ensure that the state of the closed-loop is uniform ultimate bounded. A numerical example illustrates the effectiveness of the proposed approach

To transmit or not to transmit : a discrete event-triggered communication scheme for networked Takagi-Sugeno fuzzy systems

This paper first proposes a discrete event-triggered communication scheme for a class of networked Takagi-Sugeno (T-S) fuzzy systems. This scheme has two main features: 1) Whether or not the sampled state should be transmitted is determined by the current-sampled state and the error between the current-sampled state and the latest transmitted state. Compared with those in a periodic time-triggered communication scheme, the communication bandwidth utilization is considerably reduced while preserving the desired control performance; and 2) it is a discrete event-triggered communication scheme due to the fact that the triggered conditions are only measured and checked at a constant sampling period. Compared with a continuous event-triggered communication scheme, the special hardware for continuous measurement and computation is no longer needed. Second, a networked T-S fuzzy model is delicately constructed, which not only considers nonuniform time scales in the networked T-S fuzzy model and the parallel distributed compensation fuzzy control rules but includes the aforementioned state error as well. Third, a stability criterion and a stabilization criterion about the networked T-S fuzzy system are derived, respectively. The stability criterion and stabilization criterion can provide a tradeoff to balance the required communication resource and the desired performance: Lowering the desired performance allows the network to allocate more limited bandwidth to other nodes in need. Finally, a numerical example is given to show the effectiveness of the proposed method

Event-triggered L₂ controller design of networked control systems with quantized measurement

This paper considers L2 control for a networked control system with quantized measurement. The system state is periodically sampled and quantized. An event-triggered transmitter is introduced to determine whether or not the current quantized measurement should be transmitted through the communication channel to the controller. In this event-triggered networked control system framework, a networked controller is designed to guarantee the L2 stability of the closed-loop system. Two numerical examples are given to demonstrate the effectiveness of the proposed method. It is shown that the average transmission interval could be increased substantially while the control performance is maintained. © 2012 Institute of Engineers

Decentralized event-triggered control for sampled-data systems with asynchronous sampling

This paper proposes a new decentralized event-triggered communication scheme based on asynchronous sampling. The event-triggered communication scheme does not depend on the full-order state of the system. Several spatially distributed sensor nodes are employed to collect the state data. Each node transmits the samples according to a sub-communication scheme. An L2 controller design method is developed for the decentralized event-triggered control system, which can be used to codesign of the decentralized event-triggered communication scheme and L2 controller. A numerical example illustrates the merit and effectiveness of the proposed approach.