Soft robots are characterized by ultraflexible electromechanical structures that are capable of large deformations and movements. However, the challenge of generating the high output forces necessary for manipulation persists because of the low Young’s moduli of soft materials, which limit their effectiveness in tasks such as carrying, grasping, and providing support. Inspired by shrimp exoskeletons, we designed an origami exoskeleton that features flexible-rigid arrangements and mechanical multistability. This design offers high stiffness in stable states while allowing for long-stroke transitions, making it suitable for integration with soft actuators to balance deformability and load-bearing capacity. With advantages such as high compressibility and rapid integration, these exoskeleton-enhanced arms have promising applications when mounted on unmanned ground and aerial vehicles, facilitating large-scale dexterous manipulation with the necessary load capacities. For existing soft arms, the proposed origami exoskeleton enhances the potential for manipulation within their original design framework.
We investigate a strategy to address the problem of low aircraft detection probability of space-based Automatic Dependent Surveillance-Broadcast (ADS-B). A nineteen-element hexagonal array and adaptive multi-beamforming method is proposed. This method aims to adjust the beam pattern dynamically to reduce signal collision and enlarge coverage. With the focus on the mission requirement of global aircraft detection by 2020, the appropriate gain and direction of beams are studied and designed in detail. Theoretical analysis and simulations show that this adaptive multi-beam antenna can greatly improve flight detection probability at an average reporting interval from 10 seconds to 5 seconds when compared with the traditional fixed multi-beam antenna. The results of this work show that the design of a 19-element antenna along with the adaptive multi-beamforming method can be considered as a building block of future space-based ADS-B.
The integral grid-stiffened plate is often used as the outer wall structure of spacecraft, which can reduce weight and increase strength. The Lamb wave is often used to detect damage of plate structure due to its advantages of strong penetration and minimum attenuation over long distances. When the Lamb wave crosses the stiffeners, the dispersion, reflection, transmission and mode conversion waves will be superimposed, resulting in difficulties in damage detection and structural health monitoring (SHM). This paper proposed an improved total focusing method (TFM) to locate damage in integral grid-stiffened plates based on distributed piezoelectric wafer active sensors (PWAS) array. Firstly, the appropriate working frequency was selected to generate the A0 mode Lamb wave depending on the structure and sensors, and the full matrix capture (FMC) method was introduced to collect data. Secondly, TFM was used to obtain the initial imaging results and the possible area of damage can be assessed and identified. Thirdly, the double window functions were proposed to extract the scattering signal related to the damage for the specific mode (A0). Lastly, the TFM was used again to obtain the final imaging results and the damage can be correctly identified. The proposed method has been verified by three-dimensional finite element (FE) simulation as well as experiments. The experimental results show that the damage in an aluminum alloy integral grid-stiffened plate can be located with the error of 13mm.