Radical Cyclocopolymerization of a Transformable Divinyl Monomer with a Monovinyl Monomer and Postpolymerization Modification for the Synthesis of AAB-Type Alternating Copolymers Composed of NIPAM and Vinyl Ether

In this work, we successfully synthesized AAB sequence-controlled copolymers of acrylamide (A) and vinyl ether (VE, B) via radical cyclocopolymerization of a diacrylate monomer carrying CF3-disubstututed 2-(hydroxymethyl)­phenol as the spacer (1) with an excess of VE and subsequent postpolymerization modification with aminolysis. The rational spacer design introducing two CF3–substituents allowed an efficient cyclopropagation of the divinyl monomer, alternating copolymerization with VE, and quantitative transformation. The copolymerization with 2-methoxyethyl vinyl ether (MOVE) and an aminolysis reaction with isopropylamine gave the NIPAM–NIPAM–MOVE alternating copolymer, and the aqueous solution was transparent at ambient temperature but turned cloudy upon heating. The thermal response behaviors as well as the AAB periodic sequence were evaluated through comparison with AB alternating/statistical copolymers and an N-isopropylacrylamide (NIPAM) homopolymer by temperature-variable transmittance, 1H nuclear magnetic resonance (NMR) (in D2O) measurements, and 13C/1H–13C heteronuclear single quantum coherence (HSQC) NMR spectra

Fig 12 -

(a). The Path of the Heterogeneous USV-AUV Formation Using APF. (b). The Path of the Heterogeneous USV-AUV Formation Using APF in x-y direction.</p

Fig 13 -

(a). The Path of the Heterogeneous USV-AUV Formation Using IAPF. (b). The Path of the Heterogeneous USV-AUV Formation Using IAPF in x-y direction.</p

The state of the agents.

An in-depth study on the fixed-time event-triggered obstacle avoidance consensus control in heterogeneous USV-AUV systems with input delay and uncertain disturbances are conducted in this paper. When initial state of the system fails to achieve consensus, the desired heterogeneous USV-AUV formation can be achieved by fixed-time consensus control, within a fixed predetermined time, regardless of the initial states. Besides, an event-triggered communication strategy among the agents is introduced in the system, significantly reducing communication energy consumption. By employing the proposed control strategy, the Zeno behavior also can be avoided. Additionally, an obstacle avoidance control algorithm for the heterogeneous USV-AUV system based on improved artificial potential fields (IAPF) is designed, which helps in avoiding both static and dynamic obstacles. Compared to existing research, this algorithm reduces control input jitter, resulting in smoother obstacle avoidance paths. Through extensive simulation experiments and comparisons with other methods, effectiveness and superiority of the proposed algorithm is validated.</div

S1 File -

An in-depth study on the fixed-time event-triggered obstacle avoidance consensus control in heterogeneous USV-AUV systems with input delay and uncertain disturbances are conducted in this paper. When initial state of the system fails to achieve consensus, the desired heterogeneous USV-AUV formation can be achieved by fixed-time consensus control, within a fixed predetermined time, regardless of the initial states. Besides, an event-triggered communication strategy among the agents is introduced in the system, significantly reducing communication energy consumption. By employing the proposed control strategy, the Zeno behavior also can be avoided. Additionally, an obstacle avoidance control algorithm for the heterogeneous USV-AUV system based on improved artificial potential fields (IAPF) is designed, which helps in avoiding both static and dynamic obstacles. Compared to existing research, this algorithm reduces control input jitter, resulting in smoother obstacle avoidance paths. Through extensive simulation experiments and comparisons with other methods, effectiveness and superiority of the proposed algorithm is validated.</div

The communication graph.

An in-depth study on the fixed-time event-triggered obstacle avoidance consensus control in heterogeneous USV-AUV systems with input delay and uncertain disturbances are conducted in this paper. When initial state of the system fails to achieve consensus, the desired heterogeneous USV-AUV formation can be achieved by fixed-time consensus control, within a fixed predetermined time, regardless of the initial states. Besides, an event-triggered communication strategy among the agents is introduced in the system, significantly reducing communication energy consumption. By employing the proposed control strategy, the Zeno behavior also can be avoided. Additionally, an obstacle avoidance control algorithm for the heterogeneous USV-AUV system based on improved artificial potential fields (IAPF) is designed, which helps in avoiding both static and dynamic obstacles. Compared to existing research, this algorithm reduces control input jitter, resulting in smoother obstacle avoidance paths. Through extensive simulation experiments and comparisons with other methods, effectiveness and superiority of the proposed algorithm is validated.</div

The schematic model of agent.

An in-depth study on the fixed-time event-triggered obstacle avoidance consensus control in heterogeneous USV-AUV systems with input delay and uncertain disturbances are conducted in this paper. When initial state of the system fails to achieve consensus, the desired heterogeneous USV-AUV formation can be achieved by fixed-time consensus control, within a fixed predetermined time, regardless of the initial states. Besides, an event-triggered communication strategy among the agents is introduced in the system, significantly reducing communication energy consumption. By employing the proposed control strategy, the Zeno behavior also can be avoided. Additionally, an obstacle avoidance control algorithm for the heterogeneous USV-AUV system based on improved artificial potential fields (IAPF) is designed, which helps in avoiding both static and dynamic obstacles. Compared to existing research, this algorithm reduces control input jitter, resulting in smoother obstacle avoidance paths. Through extensive simulation experiments and comparisons with other methods, effectiveness and superiority of the proposed algorithm is validated.</div

The parameters for IAPF.

An in-depth study on the fixed-time event-triggered obstacle avoidance consensus control in heterogeneous USV-AUV systems with input delay and uncertain disturbances are conducted in this paper. When initial state of the system fails to achieve consensus, the desired heterogeneous USV-AUV formation can be achieved by fixed-time consensus control, within a fixed predetermined time, regardless of the initial states. Besides, an event-triggered communication strategy among the agents is introduced in the system, significantly reducing communication energy consumption. By employing the proposed control strategy, the Zeno behavior also can be avoided. Additionally, an obstacle avoidance control algorithm for the heterogeneous USV-AUV system based on improved artificial potential fields (IAPF) is designed, which helps in avoiding both static and dynamic obstacles. Compared to existing research, this algorithm reduces control input jitter, resulting in smoother obstacle avoidance paths. Through extensive simulation experiments and comparisons with other methods, effectiveness and superiority of the proposed algorithm is validated.</div

Control inputs of heterogeneous MASs with saturation function controller (29).

Control inputs of heterogeneous MASs with saturation function controller (29).</p

The process of formation generation for heterogeneous USV-AUV MASs.

The process of formation generation for heterogeneous USV-AUV MASs.</p