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Heterogeneous switched systems are a class of special hybrid systems containing different dimensional subsystems. To research the stability and stabilisation of heterogeneous switched systems, a novel approach is presented to design static output feedback controllers for asymptotically stabilising heterogeneous continuous-time and discrete-time switched systems under arbitrary switching rules. This approach, which has less computation complexity, includes a main diagonal square block common Lyapunov function for stability analysis of heterogeneous switched systems and a main diagonal square block common homogeneous polynomial Lyapunov function for stabilisation of heterogeneous switched systems. In the study of stabilisation of heterogeneous switched systems, a two-step iterative method including two convex optimisation functions is established by sums of squares to express existing properties condition and solvable properties condition for determining block controller. At last, a practical example and two numerical examples are presented to show the feasibility of the proposed results.

Background. Curcumin shows great effects of inhibiting tumor cell proliferation, inducing apoptosis, inhibiting tumor metastasis, and inhibiting angiogenesis on a variety of tumors. However, the biological activity and possible mechanisms of curcumin in the treatment of retinoblastoma have not been fully elucidated. This study explored the potential therapeutic targets and pharmacological mechanisms of curcumin against retinoblastoma based on network pharmacology and molecular docking. Methods. The genes corresponding to curcumin targets were screened from the HERB, PharmMapper, and SwissTargetPrediction databases. Protein-protein interaction (PPI) networks were constructed for the intersecting targets in the STRING database. Cytoscape 3.7.0 was used for network topology analysis and screening of important targets. R 4.1.0 software was used for Gene Ontology (GO) function enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis of intersection targets. The molecular structures of curcumin and core target proteins were obtained from PubChem and PDB databases, and the two were preprocessed and molecularly docked using AutoDockTools and PyMOL software. Results. Through network data mining, we obtained 504 curcumin targets and 966 retinoblastoma disease targets, and 44 potential targets for curcumin treatment of retinoblastoma were obtained by mapping. Three core targets were obtained from network topology analysis. 462 biological processes, 21 cellular compositions, and 34 molecular functions were obtained by GO enrichment analysis. KEGG pathway analysis revealed 94 signaling pathways, mainly involving chemical carcinogenesis-receptor activation, chemical carcinogenesis-reactive oxygen species, viral carcinogenesis, Th17 cell differentiation, etc. The molecular docking results indicated that the binding energy of curcumin to the core targets was less than 0 kJ mol−1, among which the binding energy of RB1 and CDKN2A to curcumin was less than −5 kJ mol−1 with significant binding activity. Conclusion. Based on molecular docking technology and network pharmacology, we initially revealed that curcumin exerts its therapeutic effects on retinoblastoma with multitarget, multipathway, and multibiological functions, providing a theoretical basis for subsequent studies.

In this paper, a distributed control protocol is presented for discrete-time heterogeneous multi-agent systems in order to achieve formation consensus against link failures and actuator/sensor faults under fixed and switching topologies. A model equivalent method is proposed to deal with the heterogeneous system consists of arbitrary order systems with different parameters. Based on graph theory and Lyapunov theory, stability conditions to solve formation consensus problem are developed for the underlying heterogeneous systems with communication link failures. In order to tolerate actuator/sensor faults, a distributed adaptive controller is proposed based on fault compensation. The desired control is designed by linear matrix inequality approach together with cone complementarity linearisation algorithm. After applying the new control scheme to heterogeneous systems under the directed topologies with link failures and faults, the resulting closed-loop heterogeneous system is validated to be stable. The effectiveness of the new formation consensus control strategy and its robustness are verified by simulations.

A novel approach is proposed in this paper to design static output feedback controllers for asymptotically stabilizing continuous-time switched linear systems with minimum mode-dependent average dwell time (MMDADT). This approach adopts an iterative algorithm containing the solution of a traversal algorithm function and three optimization functions, the decision variables of which are established by the sum of squares (SOS) of matrix polynomials. The traversal algorithm function takes advantage of a polynomially parameter-bounded condition, allowing us to get the lower-bound of the Homogeneous Polynomial Lyapunov Functions’ (HPLFs) derivative. The first optimization function is a non-convex optimization function, which expresses a sufficient condition for stability analysis and computing MMDADT. The second and third optimization functions are both convex optimization functions, which are used to calculate the polynomially mode-dependent output feedback controllers. Two numerical examples are presented in order to show the feasibility of the proposed results.

In this study, an optimally distributed formation control approach is proposed for mixed-order multi-agent systems to achieve formation consistency with obstacle avoidance. The systems consist of unmanned aerial vehicles and ground robots. The authors present a formation consistency control for a mixed-order system under switching topologies. An optimally distributed method is developed by matrix transformation method and linear quadratic regulator theory, which leads to an optimisation on both horizontal and vertical control. For obstacle avoidance, a non-quadratic cost function is introduced based on optimal control. The resulting closed-loop mixed-order system is validated to be stable with an optimal performance. The formation consensus and obstacle avoidance are verified by simulations to show the effectiveness and potentials.

This work researches the problem of searching for multiple homogeneous polynomial Lyapunov functions (HPLFs) for heterogeneous switched linear systems. First, a nonconvex optimization condition is constructed to study the stability property of heterogeneous switched systems, where each Lyapunov function candidate reduces dimension to their corresponding matrix eigenvalue. Based on the stability analysis condition, a controller-dependently multiple HPLFs condition is introduced to determine controllers and explores locally minimum mode-dependent average dwell time (LMMDADT). Additionally, the existing properties condition and solvable properties condition of controllers are given in the form of HPLFs. At last, a practical example and a contrast example are both presented to show feasibility of the proposed results.

UAV automatic take-off and landing safety issue has been one of the key techniques to restrict its development. In this paper, taking a three-wheel UAV for the subject, ground taxiing modeling and control scheme of taxiing taking-off are studied. The control law designing of taxiing lateral deviation correction and longitudinal control law with the elevator are put forward. Lateral control structure adopts the method, combining lateral deviation and lateral velocity, of cooperating the front wheel with rudder, and makes some improvements on the basis of classic PID controller, with the design of fuzzy controller. According to the performance analysis of UAV taxiing, longitudinal control scheme is accomplished, assisted with elevator to complete the controller designing. Simulation results show that the fuzzy controller for large nonlinear systems has better control performance. Also the corrective effect is obvious, and taking-off process is smooth. The taking-off control scheme has some feasibility and rationality.

Analyzing the recovery process of UAV via parachute, three key issues are concluded and studied: modeling of UAV-Parachute system, estimation of wind field and the control strategy for recovery, in which the first and the last are researched mainly. Spring of the rope is introduced to the UAV-Parachute model to reflect the attitudes of UAV and tensile forces of ropes in the process, Kalman filter is used to estimate the wind field, in the control strategy, realizability and robustness to wind-field are mainly taken account for. Taking uncertainty of wind field and random navigation error into consideration, Monte-Carlo simulation is performed for 30 times, and the Circular Error Probability (CEP) is 8.23m, which reveals satisfactory accuracy and robustness of the solution proposed.

Random access channel is incorporated in IEEE 802.16 WiMAX system to transport contention-based messages in the uplink, such as bandwidth requests generated by best effort applications, from mobile stations (MSs) to the base station (BS). Regarding the packet transmissions in the random access channel, delay, throughput and power consumption are usually considered as major performance metrics. We propose an enhanced power calibration protocol to optimize the system performance in terms of channel access delay, system throughput and MS transmit power consumption. Optimal selection of power levels is formulated in order to maximize the achievable throughput while being subject to power consumption constraint of mobile stations. Our scheme can substitute the random backoff mechanism in the current the WiMAX uplink random access channel, as it can accomplish a significantly improved access delay performance without an increment of design complexity. Simulations are conducted to validate our protocol and confirm its performance superiority as compared to the random channel access method used in the current WiMAX.