Event-Triggered Sliding Mode Control Algorithms for a class of Uncertain Nonlinear Systems: Experimental Assessment Michele Cucuzzella, Gian Paolo Incremona and Antonella Ferrara Abstract— An experimental assessment of the recently in- troduced 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 dis- cussed and then it is compared with two different Model-Based Event-Triggered Sliding Mode Control algorithms. Finally, their experimental assessment is reported, obtaining satisfactory per- formance consistent with the theoretical treatment and fulfilling all the design requirements. I. I NTRODUCTION Sliding Mode Control (SMC) is a well-known control methodology able to guarantee satisfactory performance of the controlled system in spite of the presence of matched uncertainties [1], [2]. By virtue of its low complexity implementation and robustness, it can be regarded as an effective solution also in case of Networked Control Systems (NCSs), i.e., feedback systems including communication networks. Indeed, the presence of the network in the control loop can cause the occurrence of packet loss, jitter, and delayed transmissions, which can deteriorate the performance of the control system as long as this is designed in the conventional way, that is neglecting the network presence [3]. Instead, one of the methodologies which is very appreciated to design NCSs is the so-called event-triggered control [4], [5]. Event-triggered control, in contrast to time-triggered control, which features periodic transmissions of the measurements, en- ables measurements transmissions only when a pre-specified triggering condition is satisfied (or violated, depending on the adopted logic). So, while SMC can be efficacious in NCSs making the effects of the network induced nonidealities negligible by virtue of its robustness, event-triggered control can reduce such effects by significantly limiting the network overload. By using event-triggered control, in spite of the aperiodic transmission of the measurements, satisfactory stability prop- erties can be enforced. Specifically, in [4], it was proved that in case of nonlinear systems, relying on a triggering condition depending on the system state and based on the measurement This is the final version of the accepted paper submitted for inclusion in the Proceedings of the American Control Conference, Boston, MA, Jul., 2016. Work supported by EU Project ITEAM (project reference: 675999). M. Cucuzzella, G. P. Incremona and A. Ferrara are with the Dipartimento di Ingegneria Industriale e dell’Informazione, University of Pavia, via Ferrata 1, 27100 Pavia, Italy (e-mail: {michele.cucuzzella01, gianpaolo.incremona01}@universitadipavia.it, antonella.ferrara@unipv.it). Fig. 1. The networked sliding mode control scheme. error between the current state and the last state transmitted over the network, the Input-to-State Stability (ISS) of the controlled system can be guaranteed. In the literature, the basic event-triggered control approach have been further elaborated so as to take into account the possible knowledge of a nominal model of the plant. This has produced the so-called model-based event-triggered control discussed in [6], [7]. This approach has been recently effectively exploited in conjunction with SMC [8]–[10], and model predictive control (MPC), even in case of mixed logical dynamical (MLD) systems [11]–[14]. Moreover, a novel genuine Event-Triggered Second Order Sliding Mode (ET- SOSM) control strategy has been recently proposed for affine nonlinear systems [15]. In the present paper, making reference to the class of nonlinear systems affected by matched uncertainty, three event-triggered sliding mode control strategies are introduced and discussed. In particular, a novel genuine Event-Triggered SMC (ET-SMC) strategy is proposed. Then, it is com- pared with two different Model-Based Event-Triggered SMC (MBET-SMC) strategies, already published in the literature [8], [9]. The aim of the paper is to provide an assessment of the three strategies on the basis of experiments performed on a real setup. This is a water tank with a communication network between the plant and the control unit. Satisfactory results have been obtained for all the strategies. The results confirm the theoretical properties of the considered event- triggered sliding mode control approaches and their suitability