Schedulability Analysis for Fixed Priority Real-Time Systems with Energy-Harvesting

Abstract

International audienceThis paper introduces sufficient schedulability tests for fixed-priority pre-emptive scheduling of a real-time system under energy constraints. In this problem, energy is harvested from the ambient environment and used to replenish a storage unit or battery. The set of real-time tasks is decomposed into two different types of task depending on whether their rate of energy consumption is (i) more than or (ii) no more than the storage unit replenishment rate. We show that for this task model, where execution may only take place when there is sufficient energy available, the worst-case scenario does not necessarily correspond to the synchronous release of all tasks. We derive sufficient schedulability tests based on the computation of worst-case response time upper and lower bounds. We examine both the effectiveness and the tightness of the bounds, via an empirical investigation

Energy Management for Energy Harvesting-Based Embedded Systems: A Systematic Mapping Study

“…As shown in Figure 7, 31% of papers focused on energy scheduling (see, e.g., [52,59,62,65,97,107]), such as studying how to combine energy-constrained scheduling algorithms with the introduction of an energy harvesting unit; 28% of papers focused on energy harvesting methods (see, e.g., [29]), such as using reinforcement learning (RL) to automatically configure a device to maximize energy storage or minimize energy consumption as much as possible (see, e.g., [23,29,36,45]). Since the energy harvesting by EHES is affected by geographic location and the surrounding environment, the collected data are different.…”

“…In this case, how to ensure the normal scheduling of system tasks is a signification problem. In this regard, many researchers have proposed various approaches, for example, global controller track the optimal operating point of the photovoltaic panel, state of charge management for the supercapacitor, and energy harvesting real-time task scheduling with DVFS in the embedded device [5]; the time constraints of battery-powered embedded devices are extended to energy constraints [35,58,65,105,109]; a new strategy was designed in conjunction with traditional battery-powered embedded system scheduling algorithm after considering energy attributes [62,93,97,107]. Energy consumption has always been a long-term problem for embedded systems.…”

The PFPASAP algorithm for energy harvesting real-time systems with a non-ideal supercapacitor

“…In 20 14, the authors of [3] in [2] introduced suffIcient schedulability tests for the PFP ASAP algorithm when there are gaining and consuming tasks. The authors of this paper have fIrst shown when there are gaining and consuming tasks, synchronous release of all tasks is not the worst case scenario for response time analysis then they present two upper bound and one lower bound response time computation method to provide suffIcient schedulability test.…”

“…Since in small embedded systems, the stable energy is needed not a large amount of energy, we have considered the piezoelectric vibration as an energy source. According to [2] the piezoelectric vibration can provide a stable energy.…”

“…The second approach includes scavenging energy from different sources like solar radiation, thermal gradients, ambient vibrations, radio frequency, etc. [2], and converting them into electrical power and storing in an energy storage unit such as rechargeable batteries (e.g. NiMH and Li-ion) and supercapacitors [1].…”