ABSTRACT
Nature abounds with examples of superior mobility through the fusion of aerial and ground movement. Drawing inspiration from such multimodal locomotion, we introduce a high-performance hybrid hopping and flying robot. The proposed robot seamlessly integrates a nano quadcopter with a passive telescopic leg, overcoming limitations of previous jumping mechanisms that rely on stance phase leg actuation. Based on the identified dynamics, a thrust-based control method and detachable active aerodynamic surfaces were devised for the robot to perform continuous jumps with and without position feedback. This unique design and actuation strategy enable tuning of jump height and reduced stance phase duration, leading to agile hopping locomotion. The robot recorded an average vertical hopping speed of 2.38 meters per second at a jump height of 1.63 meters. By harnessing multimodal locomotion, the robot is capable of intermittent midflight jumps that result in substantial instantaneous accelerations and rapid changes in flight direction, offering enhanced agility and versatility in complex environments. The passive leg design holds potential for direct integration with conventional rotorcraft, unlocking seamless hybrid hopping and flying locomotion.
ABSTRACT
Uncertain dynamics and unknown time-varying disturbances always exist in servo systems and deteriorate tracking accuracy significantly. To tackle the problem, this paper presents a novel adaptive robust control scheme based on neural networks and the robust integral of the sign of the error (RISE) method. In the proposed scheme, a new neural network compensator is developed, where a reference-driven neural network and an error-driven neural network are employed to compensate for uncertain system dynamics and unknown time-varying disturbances, respectively. And an RISE-based robust feedback controller is designed to suppress uncompensated dynamics. Asymptotic tracking control of the servo system with uncertain dynamics and unknown time-varying disturbances is guaranteed by using the Lyapunov theory. Comparative experiments and simulations with different reference signals and various types of external disturbances were conducted based on a linear motor-driven stage. Experimental and simulational results verify the superior tracking performance and powerful disturbance rejection ability of the proposed method.
ABSTRACT
The ancient discussion and modern clinical application regarding Yingxiang (LI 20) and Neiyingxiang (EX-HN 9) in acupuncture verses are explored. Acupuncture verses are the summary of clinical experiences of acupuncture scholars in the past dynasties, of which the records on application of Yingxiang (LI 20) and Neiyingxiang (EX-HN 9) mainly focused on nasal, facial and head-eye diseases, which is characterized with overall summarization, brilliant exposition, simple language, and distinctive characteristics. Nowadays, based on the ancient usage, the clinical application about these two acupoints is continuously developing. If the ancient acupuncture verses could be understood thoroughly, the clinical practice could be better guided and its effects could be improved.
