From Studying Real Hummingbirds to Designing Hummingbird-Like Robots—A Literature Review <s> VIII. CONCLUSION <s> Vertical lifting performance in 67 hummingbird species was studied across a 4000 m elevational gradient. We used the technique of asymptotic load-lifting to elicit maximum sustained muscle power output during loaded hovering flight. Our analysis incorporated direct measurements of maximum sustained load and simultaneous wingbeat kinematics, together with aerodynamic estimates of mass-specific mechanical power output, all within a robust phylogenetic framework for the Trochilidae. We evaluated key statistical factors relevant to estimating slopes for allometric relationships by performing analyses with and without phylogenetic information, and incorporating species-specific measurement error. We further examined allometric relationships at different elevations because this gradient represents a natural experiment for studying physical challenges to animal flight mechanics. Maximum lifting capacity (i.e. vertical force production) declined with elevation, but was either isometric or negatively allometric with respect to both body and muscle mass, depending on elevational occurrence of the corresponding taxa. Maximum relative muscle power output exhibited a negative allometry with respect to muscle mass, supporting theoretical predictions from muscle mechanics. <s> BIB001 </s> From Studying Real Hummingbirds to Designing Hummingbird-Like Robots—A Literature Review <s> VIII. CONCLUSION <s> Bio-inspired flapping wings with a wrinkled wing membrane were designed and fabricated. The wings consist of carbon fibre-reinforced plastic frames and a polymer film with microscale wrinkles inspired by bird feathers and the corrugations of insect wings. The flexural and tensile stiffness of the wrinkled film can be controlled by modifying the orientations and waveforms of the wrinkles, thereby expanding the design space of flexible wings for micro flapping-wing aerial robots. A self-organization phenomenon was exploited in the fabrication of the microwrinkles such that microscale wrinkles spanning a broad wing area were spontaneously created. The wavy shape of these self-organized wrinkles was used as a mould, and a Parylene film was deposited onto the mould to form a wrinkled wing film. The effect of the waveforms of the wrinkles on the film stiffness was investigated theoretically, computationally and experimentally. Compared with a flat film, the flexural stiffness was increased by two orders of magnitude, and the tensile stiffness was reduced by two orders of magnitude. To demonstrate the effect of the wrinkles on the actual deformation of the flapping wings and the resulting aerodynamic forces, the fabricated wrinkled wings were tested using a tethered electric flapping mechanism. Chordwise unidirectional wrinkles were found to prevent fluttering near the trailing edge and to produce a greater aerodynamic lift compared with a flat wing or a wing with spanwise wrinkles. Our results suggest that the fine stiffness control of the wing film that can be achieved by tuning the microwrinkles can improve the aerodynamic performance of future flapping-wing aerial robots. <s> BIB002 </s> From Studying Real Hummingbirds to Designing Hummingbird-Like Robots—A Literature Review <s> VIII. CONCLUSION <s> Abstract This paper proposes a sequential time-dependent reliability analysis method by considering time sequence and correlation of failure processes for the lower extremity exoskeleton under uncertainty, which will provide an approach to improving the comfort and safety for the wearer. A kernel density function based uncertainty quantification method is provided for precisely quantitatively estimating the time-dependent reliability of joints and the position of the end-effector firstly. After decoupling time sequence and failures correlation due to error propagation, the original reliability problem is then transferred to a series time-dependent reliability model. The time-dependent system reliability analysis is finally realized by calculating conditional probability. A case study is implemented to testify the effectiveness of the proposed method. <s> BIB003 </s> From Studying Real Hummingbirds to Designing Hummingbird-Like Robots—A Literature Review <s> VIII. CONCLUSION <s> Food security is one of the societal challenge topics. As one-third of all food consumed by humans relies on animal pollination currently, this research provides an emerging solution to food supply reduction caused by population shrinking of natural pollinators, so as to reduce its impact on ecological relationships, ecosystem conservation and stability, genetic variation in the crop plant community, floral diversity, specialisation and evolution. This paper develops a conceptual technical roadmap of autonomous pollination for future farming using robotic micro air vehicle pollinators (MPrs). The research provides new insights into autonomous design and manufacture and into possible ways to increase the production efficiency which shortens the time from lab to market. The autonomous MPrs are realized using artificial intelligence and human expertise in the loop for smart agricultural industry. Further, this work identifies scientific and technological advances that are expected to translate, within proposed regulatory frameworks, into the pervasive use of MPrs for agricultural applications and beyond. <s> BIB004 </s> From Studying Real Hummingbirds to Designing Hummingbird-Like Robots—A Literature Review <s> VIII. CONCLUSION <s> Abstract Time-dependent reliability analysis is an important and challenging issue due to the time-dependent motion and loadings of a mechanism. In this paper, a general framework and corresponding methods are proposed to deal with the time-dependent reliability analysis of a mechanism effectively. The envelope function is used to estimate the finite expansion points, which converts the time-dependent reliability problem to the time-independent reliability problem under the general probability distribution. The covariance matrix is then derived with the vine-copula function to describe the correlation of the performance at the obtained expansion points. With the covariance matrix, the joint probability density function (PDF) is acquired based on the kernel density estimation (KDE) method. The time-dependent reliability is finally estimated by the integral. The case study with different conditions is provided to validate the efficiency and accuracy of the proposed approach. <s> BIB005
In this paper, the insects and birds morphologies are firstly introduced, followed by the morphology study of hummingbird including the muscles, skeleton structure to investigate the hummingbird flying, in which the weight distribution of each component and flapping mechanisms are studied. The reasonable weight distribution of components is important to design a successful FWMAD. After that, the aerodynamic of hummingbirds is presented to interpret the reasons of hovering flight. Then, the scale laws and geometry similarity are explored and summarized before obtaining the relations between parameters of wing performance and weight. The wings are designed based on the scale laws and wing's efficiency is also proofed by flying test. Therefore, the studied scale laws in this paper may be reasonable and acceptable. Also, designed wings based on different materials and methods are summarized. Last, the morphology of tail is studied and designed tails are discussed. The results show that a tail may be employed in hovering stability of twin-wing FWMADs. Therefore, we believe that the current studies provide a simple but useful dataset and guideline for biologists and engineers who study the morphology of hummingbirds and future development of similar sized FWMADs. Our future research will focus on further experimental research and the FWMAD's reliability design and improvement under uncertainties using artificial intelligence driven approaches  , BIB002 ,  - BIB004 , BIB003 - BIB005 . APPENDIX   TABLE 4 . Body, muscle parameters of various hummingbird species adapted by BIB001 . BIB001 . 