Event-Triggered Sliding Mode control algorithms for a class of uncertain nonlinear systems: Experimental assessment

An experimental assessment of the recently introduced event-triggered sliding mode control approach is presented in this paper. The major design requirement, in this approach, is to reduce the number of transmissions over the network, while guaranteeing that the sliding mode control is stabilizing with appropriate robustness in front of matched uncertainties. In the present paper a novel Event-Triggered Sliding Mode Control algorithm is first introduced and discussed and then it is compared with two different Model-Based Event-Triggered Sliding Mode Control algorithms. Finally, their experimental assessment is reported, obtaining satisfactory performance consistent with the theoretical treatment and fulfilling all the design requirements

EVENT-TRIGGERED SLIDING MODE CONTROL FOR CONSTRAINED NETWORKED CONTROL SYSTEMS

The paper describes a Non-linear Control (ETNC) approach for constrained Networked Feedback Control Systems (NFCS). The real-time controller execution is implemented based on the Event-triggering paradigm. A  nonlinear variable structure is used for the controller design. The nonlinear approach is based on the predefined sliding variable defined by the system states with a nonlinear switching function. The system's stability is analyzed regarding the evolution of the sliding variable. The Event-Triggered operation of the nonlinear controller is based on the prescribed triggering rule. The stability boundary of the sliding variable is subject to the preselected triggering condition, whose selection is a tradeoff of system performance, networks constraints and transmission capabilities. The main focus of the Event triggering approach is lowering network resources utilization in the steady-state behavior of the NFCS. The presented approach ensures a non-zero inter-event time of controller execution, which enables scheduling and optimization of the network operation regarding the network constraints and real-time system performance. The efficiency of the presented method is presented with a comparison of the classical time triggering approach.  The real measurement supports the results

Networked Sliding Mode Control with chattering alleviation

This paper addresses the design of a model-based event-triggered strategy based on Sliding Mode Control (SMC), so that the overall proposal can be regarded as a networked control scheme. The objective is to reduce to a minimum the number of transmissions of the plant state over the network, in order to alleviate delays and packet loss induced by data transmission traffic. The key idea consists in using the actual system state or a suitably updated model state within the control law, depending on the magnitude of the sliding variable. More specifically, the model state is used within a boundary layer of the sliding manifold, so that a pseudo-equivalent control can be determined. This latter is continuous, which implies an intrinsic chattering alleviation capability of the proposed strategy. The designed networked scheme is assessed in simulation with satisfactory results