In this article, a novel real-time time-optimal trajectory planning (TOTP) approach is proposed for rotorcrafts under velocity constraints and complex nonconvex thrust, attitude input constraints. Different from existing works, the proposed method is the first real-time TOTP solution for rotorcrafts subject to velocity constraints and these nonconvex input constraints. The key insight is to transform the thrust and attitude constraints into the inequality constraints on the quadratic nonlinear function of the path parameter acceleration and the squared velocity, by exploiting the differential flatness characteristic of the rotorcraft. As a result, the constraints can be formulated as the problem of jointly solving analytical quadratic inequalities. On this basis, a path acceleration calculation algorithm is proposed to obtain the backward and forward acceleration profiles. In addition, by formulating the well-known field of view (FOV) constraints into the attitude constraints, the proposed framework can further guarantee the FOV constraint for visual servoing of rotorcrafts. Comparative experimental results are presented to show the superior performance of the proposed approach when compared with the second-order cone programming approach. In addition, some visual servoing experiments are conducted to demonstrate the capability of the proposed method to guarantee the FOV constraint.

中文翻译：

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旋翼飞机的姿态约束时间最优轨迹规划：理论及在视觉伺服中的应用

本文提出了一种新颖的实时时间最优轨迹规划（TOTP）方法，该方法适用于旋翼飞机在速度约束和复杂的非凸推力，姿态输入约束下。与现有工作不同的是，该方法是旋翼航空器在速度约束和非凸输入约束下的第一个实时TOTP解决方案。关键的见解是通过利用旋翼飞机的微分平坦度特性，将推力和姿态约束转换为路径参数加速度和速度平方的二次非线性函数的不等式约束。结果，可以将约束条件表述为共同解决二次二次不等式的问题。在此基础上，提出了一种路径加速度计算算法，以获取后向和前向加速度曲线。另外，通过将众所周知的视野约束（FOV）约束化为姿态约束，所提出的框架可以进一步保证旋翼飞机视觉伺服的FOV约束。对比实验结果表明，与二阶锥规划方法相比，该方法具有优越的性能。此外，进行了一些视觉伺服实验，以证明所提方法能够保证视场约束。所提出的框架可以进一步保证旋翼飞机视觉伺服的视场约束。对比实验结果表明，与二阶锥规划方法相比，该方法具有优越的性能。此外，进行了一些视觉伺服实验，以证明所提方法能够保证视场约束。所提出的框架可以进一步保证旋翼飞机视觉伺服的视场约束。对比实验结果表明，与二阶锥规划方法相比，该方法具有优越的性能。此外，进行了一些视觉伺服实验，以证明所提方法能够保证视场约束。