Traditional Control Solutions Research Articles

Assessment of the potential correlation between Smart Readiness Indicator and energy performance in a dataset of buildings in South Tyrol

The Energy Performance of Buildings Directive introduced the Smart Readiness Indicator (SRI), a common European system for assessing buildings’ smart readiness. While not mandatory across the European Union, some countries have initiated trial phases, and several studies already examined its application in different Member States. In this work, we present the findings of an extensive application of the SRI methodology on a sample of 59 recently constructed or recently renovated high-performance buildings in South Tyrol, Italy. Our research focused on two main objectives: (1) characterizing the level of smart readiness of state-of-the-art modern buildings in the Italian Alpine region of South Tyrol, and (2) discussing the potential correlation between the level of smart readiness and building energy performance class. Specifically, the HVAC and building systems with the most widespread adoption of advanced smart technologies were identified, as well as those configurations with traditional control solutions suggesting potential for improvement. The analysis proved that the different building categories present various levels of smart readiness, which is higher for the local office buildings and lower for the residential ones. No particular correlation was found between smart readiness and energy performance class, suggesting the need of adopting the SRI to give a more comprehensive characterization of the building performances.

A simplified model‐based nonlinear control with fast response and simple design flow for HB‐LLC resonant converter

SummaryLLC resonant converters have attracted much attention for its characteristics of high efficiency and high‐power density in recent years. Yet, with the diversity of application needs such as photovoltaic power generation and electric vehicles, traditional control solutions have gradually been unable to meet the increasing requirements, such as fast response to parameters perturbations. Besides, LLC converter is a high‐order nonlinear system, and it adds complexity to controller design. In order to solve these issues, taking the HB‐LLC converter as an example, this paper presents a simplified model‐based nonlinear control with fast response and simple design. The proposed controller is based on a second‐order model of LLC circuit, and the reverse design idea of the backstepping method is used to simplify the controller design. An experimental platform is built, and the results show that compared with PID control and linear active disturbance rejection control (LADRC), the proposed method has much smaller voltage undershoot (approximately 53.1% of PID and 68.4% of LADRC) and shorter settling time (approximately 27.8% of PID and 39.3% of LADRC) under input voltage change.

A cerebellar-based solution to the nondeterministic time delay problem in robotic control

The presence of computation and transmission-variable time delays within a robotic control loop is a major cause of instability, hindering safe human-robot interaction (HRI) under these circumstances. Classical control theory has been adapted to counteract the presence of such variable delays; however, the solutions provided to date cannot cope with HRI robotics inherent features. The highly nonlinear dynamics of HRI cobots (robots intended for human interaction in collaborative tasks), together with the growing use of flexible joints and elastic materials providing passive compliance, prevent traditional control solutions from being applied. Conversely, human motor control natively deals with low power actuators, nonlinear dynamics, and variable transmission time delays. The cerebellum, pivotal to human motor control, is able to predict motor commands by correlating current and past sensorimotor signals, and to ultimately compensate for the existing sensorimotor human delay (tens of milliseconds). This work aims at bridging those inherent features of cerebellar motor control and current robotic challenges—namely, compliant control in the presence of variable sensorimotor delays. We implement a cerebellar-like spiking neural network (SNN) controller that is adaptive, compliant, and robust to variable sensorimotor delays by replicating the cerebellar mechanisms that embrace the presence of biological delays and allow motor learning and adaptation.

Neutral daylight illumination with variable transmission glass: Theory and validation

The dynamic control of daylight is seen as key for the effective exploitation of natural illumination in buildings. Traditional control solutions are invariably used in a sub-optimal manner: blinds/shades are left down for long periods and lights are left switched on. A glazing with a transmissivity that varies continuously between clear and dark extremes, and which can be controlled automatically, could be much more effective in providing a ‘well-tempered’ daylit environment that meets occupants needs. Amongst the different types of variable transmission glazing that have undergone extensive research and development in the last few decades, those based on electrochromism appear to have the best performance characteristics and the greatest market potential. Electrochromic (EC) glazing generally exhibits a shift in spectral transmission as the glass darkens, e.g. causing it to appear blue as it tints. Occupants, however, are believed to prefer a neutral spectrum of daylight illumination without any pronounced hue. In this paper, the authors show that it is possible to maintain a neutral spectrum of illumination with electrochromic (EC) glazing under normal operation provided that just a small proportion of the EC glazing is kept in the clear state. A theoretical model to predict the daylight spectrum resulting from any arbitrary combination of clear and tinted glazing is described. Predictions from the model are compared with measurements of the daylight spectra in an office with EC glazing under various states of tint. The predicted spectra show excellent agreement with the measurements. The model is applicable to any combination of clear and/or tinted glass panels irrespective of the glazing type(s). The paper concludes with a discussion of design considerations for the effective deployment of EC glazing.