Although the pectoralis major myocutaneous flap is often used in head and neck reconstruction, the extension of the skin paddle beyond the inferior limits of the muscle has not been well described. We aim to clarify t...Although the pectoralis major myocutaneous flap is often used in head and neck reconstruction, the extension of the skin paddle beyond the inferior limits of the muscle has not been well described. We aim to clarify the design and application of this extended flap in head and neck reconstruction. In this retrospective study, consecutive cases of extended pectoralis major myocutaneous flap reconstruction of post-ablative head and neck defects at a single tertiary referral center were included for analysis. In 7 cases an extended pectoralis major flap was utilized, in which the skin paddle was extended beyond the inferior border of the pectoralis major to include the rectus sheath. Skin and soft tissue as well as composite defects of the oral cavity, parotid/temporal region and neck were reconstructed. All flaps healed satisfactorily with no loss of skin viability. The extended pectoralis major myocutaneous flap is robust and has versatile applications for reconstruction of large, high and three dimensionally complex defects in the head and neck region.展开更多
围绕无人直升机实际飞行中的不确定性问题,将扩张状态观测器(extended state observer,ESO)与自适应反步法相结合设计控制器来实现无人直升机轨迹的鲁棒跟踪控制。首先,建立了无人直升机的数学模型,建模过程中考虑未建模动态、模型简化...围绕无人直升机实际飞行中的不确定性问题,将扩张状态观测器(extended state observer,ESO)与自适应反步法相结合设计控制器来实现无人直升机轨迹的鲁棒跟踪控制。首先,建立了无人直升机的数学模型,建模过程中考虑未建模动态、模型简化误差、外界大气扰动以及燃油消耗导致的惯性参数摄动等多种不确定性来源。同时,将主旋翼一阶挥舞动态耦合进无人直升机6-DOF刚体动力学方程,建立了简洁且又反映无人直升机旋翼挥舞这一重要特征的等效模型。然后,基于ESO和自适应反步法设计了位置控制器、姿态控制器以及力矩控制器,其中利用自适应策略对无人直升机质量及惯性矩阵等慢变摄动参数进行估计,利用ESO对未建模动态及外界阵风等高频扰动进行观测,并通过前馈补偿实现对系统不确定性的综合抑制。最后,通过数值仿真验证了方法的可行性和有效性。仿真结果表明,该方法比纯自适应反步法具有更高的不确性抑制效率和控制精度,能够实现无人直升机在多种不同类型扰动同时作用下轨迹的鲁棒跟踪控制。展开更多
文摘Although the pectoralis major myocutaneous flap is often used in head and neck reconstruction, the extension of the skin paddle beyond the inferior limits of the muscle has not been well described. We aim to clarify the design and application of this extended flap in head and neck reconstruction. In this retrospective study, consecutive cases of extended pectoralis major myocutaneous flap reconstruction of post-ablative head and neck defects at a single tertiary referral center were included for analysis. In 7 cases an extended pectoralis major flap was utilized, in which the skin paddle was extended beyond the inferior border of the pectoralis major to include the rectus sheath. Skin and soft tissue as well as composite defects of the oral cavity, parotid/temporal region and neck were reconstructed. All flaps healed satisfactorily with no loss of skin viability. The extended pectoralis major myocutaneous flap is robust and has versatile applications for reconstruction of large, high and three dimensionally complex defects in the head and neck region.
文摘围绕无人直升机实际飞行中的不确定性问题,将扩张状态观测器(extended state observer,ESO)与自适应反步法相结合设计控制器来实现无人直升机轨迹的鲁棒跟踪控制。首先,建立了无人直升机的数学模型,建模过程中考虑未建模动态、模型简化误差、外界大气扰动以及燃油消耗导致的惯性参数摄动等多种不确定性来源。同时,将主旋翼一阶挥舞动态耦合进无人直升机6-DOF刚体动力学方程,建立了简洁且又反映无人直升机旋翼挥舞这一重要特征的等效模型。然后,基于ESO和自适应反步法设计了位置控制器、姿态控制器以及力矩控制器,其中利用自适应策略对无人直升机质量及惯性矩阵等慢变摄动参数进行估计,利用ESO对未建模动态及外界阵风等高频扰动进行观测,并通过前馈补偿实现对系统不确定性的综合抑制。最后,通过数值仿真验证了方法的可行性和有效性。仿真结果表明,该方法比纯自适应反步法具有更高的不确性抑制效率和控制精度,能够实现无人直升机在多种不同类型扰动同时作用下轨迹的鲁棒跟踪控制。
