Annelid-inspired high-elongation origami robot using partial material removal.

Existing soft robots face challenges given the need for an improved flexible robot elongation rate, bending angle and movement flexibility in space target acquisition, disaster search and rescue, unknown environment detection and other fields. Yoshimura tubular origami shows good applied performance with regard to the axial elongation ratio. However, due to the characteristics of nonrigid folding and a negative Poisson's ratio, the axial elongation length and bending angle of the Yoshimura tubular origami mechanism are limited. Annelids show highly flexible body movement. By analyzing the main factors limiting the axial elongation rate of the Yoshimura tubular origami mechanism and imitating the morphological characteristics and motion mechanism of annelid somite joints, we proposed a method to achieve high flexibility and large angle bending of a tubular origami mechanism based on local material removal and macroscopic elimination of the negative Poisson's ratio. Combined with a Ni-Ti memory alloy wire segmented driving scheme based on force constraints and geometric constraints a continuous origami robot is designed. The optimal cutting amount of the origami mechanism is determined by experiments, and the maximum elongation ratio and bending angle of the origami mechanism reach 2.5 and 3 times those before material removal, respectively. The paper folding module unit was solved in a kinematic analysis workspace. Finally, a prototype was used to verify the performance and demonstrate the application potential of the robot in an unstructured rescue scene.

[Instantaneous chaometry applied in heart rate study].

Instantaneous chaometry was defined on uniformity theory constructed by the present authors. The sample data, sinus heart rate data and arrhythmia heart rate data from MIT-BIH were analyzed with instantaneous chaometry (ICM); the situation not being distinguished with HRV can be differentiated with ICM. The normal sinus rhythm was found to be of three evident characteristics: (1) instant returning to zero, (2) stability-stable characteristic of ICM on the initial position, (3) interval of mean: 2-7, variance: 1.5-5. The third characteristic shows that the variability of ICM is necessary. The studies on arrhythmia database showed that arrhythmia cases exhibited no returning to zero, nonstability of ICM on the initial position, too small mean or standard deviation, respectively. Evidently, the arithmetic of ICM is simple; ICM can be easily applied in clinical and pathologic analyses.