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This article puts forward an event-triggered adaptive neural tracking control strategy for a class of uncertain fractional-order nonstrict-feedback nonlinear systems with full-state constraints and dead-zone inputs. The proposed control strategy is capable of surmounting an inherent shortcoming in most traditional backstepping control approaches which results from the repeated differentiation of virtual control functions, and enhancing the transmission efficiency of control signals by introducing an event-triggered mechanism with a dynamic threshold condition. Furthermore, by constructing a novel barrier Lyapunov function in each step of the backstepping procedure, the design difficulty arising from the system state constraints issue under fractional-order cases is resolved. It is strictly proved that the tracking error can converge into a desired small neighborhood of the origin and all signals in the closed-loop system are bounded. Finally, a simulation example is given to verify the effectiveness of our proposed control strategy.

Summary This article studies the adaptive tracking control problem for a class of uncertain nonlinear systems with unmodeled dynamics and disturbances. First, a fuzzy state observer is established to estimate unmeasurable states. To overcome the problem of calculating explosion caused by the repeated differentiation of the virtual control signals, the command filter with a compensation mechanism is applied to the controller design procedure. Meanwhile, with the help of the fuzzy logic systems and the backstepping technique, an adaptive fuzzy control scheme is proposed, which guarantees that all signals in the closed‐loop systems are bounded, and the tracking error can converge to a small region around the origin. Furthermore, the stability of the systems is proven to be input‐to‐state practically stable based on the small‐gain theorem. Finally, a simulation example verifies the effectiveness of the proposed control approach.

Heat generation occurs in landfills due to the degradation of organic matter. This paper aims to evaluate the heat generated due to the organic matter degradation of synthetic municipal solid waste using a bioreactor. A double-layered bioreactor is developed for the waste degradation test, during which the waste temperature, ambient temperature, gas emissions and total degraded organic matter are measured. The waste degradation tests last more than 350 h and indicate peak values for both the waste temperature and the rate of gas emission. The heat generated from waste degradation is determined by accounting for increases in the waste temperature, gas emissions and bioreactor conduction. The total heat generated per unit mass of the dry organic matter ranges from 1503 to 1776 kJ, which shows reasonable comparison results with the reported heat values. The variation in the total heat generated with waste degradation time is well predicted by an empirical formula, in which the heat parameters are correlated with the times of the peak waste temperature and peak heat generation rate.

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