Locomotion performance degradation after carrying payloads is a significant challenge for insect-scale microrobots.Previously,a legged microrobot named BHMbot with a high load-carrying capacity based on front-leg actu...Locomotion performance degradation after carrying payloads is a significant challenge for insect-scale microrobots.Previously,a legged microrobot named BHMbot with a high load-carrying capacity based on front-leg actuation configuration and efficient running gait was proposed.However,insects,mammals and reptiles in nature typically use their powerful rear legs to achieve rapid running gaits for predation or risk evasion.In this work,the load-carrying capacity of the BHMbots with front-leg actuation and rear-leg actuation configurations is comparatively studied.Simulations based on a dynamic model with four degrees of freedom,along with experiments,have been conducted to analyze the locomotion characteristics of the two configurations under different payload masses.Both simulation and experimental results indicate that the load-carrying capacity of the microrobots is closely related to their actuation configurations,which leads to different dynamic responses of the microrobots after carrying varying payload masses.For microrobots with body lengths of 15 mm,the rear-leg actuation configuration exhibits a 31.2%enhancement in running speed compared to the front-leg actuation configuration when unloaded.Conversely,when carrying payloads exceeding 5.7 times the body mass(350 mg),the rear-leg actuation configuration demonstrates an 80.1%reduction in running speed relative to the front-leg actuation configuration under the same payload conditions.展开更多
We use an efficient earthquake simulator that incorporates rate-state constitutive properties and uses boundary element method to discretize the fault surfaces, to generate the synthetic earthquakes in the fault syste...We use an efficient earthquake simulator that incorporates rate-state constitutive properties and uses boundary element method to discretize the fault surfaces, to generate the synthetic earthquakes in the fault system. Rate-and-state seismicity equation is subsequently employed to calculate the seismicity rate in a region of interest using the Coulomb stress transfer from the main shocks in the fault system. The Coulomb stress transfer is obtained by resolving the induced stresses due to the fault patch slips onto the optimal-oriented fault planes. The example results show that immediately after a main shock the aftershocks are concentrated in the vicinity of the rupture area due to positive stress transfers and then dis- perse away into the surrounding region toward the back- ground rate distribution. The number of aftershocks near the rupture region is found to decay with time as Omori aftershock decay law predicts. The example results dem- onstrate that the rate-and-state fault system earthquakesimulator and the seismicity equations based on the rate- state friction nucleation of earthquake are well posited to characterize the aftershock distribution in regional assess- ments of earthquake probabilities.展开更多
Gastrointestinal(GI)diseases,especially cancers,are responsible for 25%of global cancer cases and one-third of cancer-related deaths,with treatment costs projected to surpass$21 billion annually by 2030[1,2].Early dia...Gastrointestinal(GI)diseases,especially cancers,are responsible for 25%of global cancer cases and one-third of cancer-related deaths,with treatment costs projected to surpass$21 billion annually by 2030[1,2].Early diagnosis and continuous monitoring of physiological signals are critical for the effective prevention and management of these conditions[3].Since the concept of ingestible electronic pills was first proposed in the 1960s[4]and the first commercially approved device was launched in 2001[5],ongoing technological advances have increasingly demonstrated the promise of wireless ingestible capsules as a minimally invasive platform for personalized gastroenterological care(Table S1 online).展开更多
基金supported in part by Beijing Natural Science Foundation under Grant 3232010in part by the National Natural Science Foundation of China under Grant 12002017+2 种基金in part by AECC Industry-university Collocation Fund under Grant HFZL2023CXY026in part by Beihang Outstanding Young Scholars Project under Grant YWF-23-L-1201in part by 111 Project under Grant B08009.
文摘Locomotion performance degradation after carrying payloads is a significant challenge for insect-scale microrobots.Previously,a legged microrobot named BHMbot with a high load-carrying capacity based on front-leg actuation configuration and efficient running gait was proposed.However,insects,mammals and reptiles in nature typically use their powerful rear legs to achieve rapid running gaits for predation or risk evasion.In this work,the load-carrying capacity of the BHMbots with front-leg actuation and rear-leg actuation configurations is comparatively studied.Simulations based on a dynamic model with four degrees of freedom,along with experiments,have been conducted to analyze the locomotion characteristics of the two configurations under different payload masses.Both simulation and experimental results indicate that the load-carrying capacity of the microrobots is closely related to their actuation configurations,which leads to different dynamic responses of the microrobots after carrying varying payload masses.For microrobots with body lengths of 15 mm,the rear-leg actuation configuration exhibits a 31.2%enhancement in running speed compared to the front-leg actuation configuration when unloaded.Conversely,when carrying payloads exceeding 5.7 times the body mass(350 mg),the rear-leg actuation configuration demonstrates an 80.1%reduction in running speed relative to the front-leg actuation configuration under the same payload conditions.
基金supported by the NSF Frontiers in Earth-System Dynamics(EAR-1135455)the Extreme Science and Engineering Discovery Environment(XSEDE),which is supported by National Natural Science Foundation grant No.OCI-1053575the Blue Waters sustained-petascale computing project,which is supported by the National Natural Science Foundation(award No.OCI 07-25070)and the state of Illinois
文摘We use an efficient earthquake simulator that incorporates rate-state constitutive properties and uses boundary element method to discretize the fault surfaces, to generate the synthetic earthquakes in the fault system. Rate-and-state seismicity equation is subsequently employed to calculate the seismicity rate in a region of interest using the Coulomb stress transfer from the main shocks in the fault system. The Coulomb stress transfer is obtained by resolving the induced stresses due to the fault patch slips onto the optimal-oriented fault planes. The example results show that immediately after a main shock the aftershocks are concentrated in the vicinity of the rupture area due to positive stress transfers and then dis- perse away into the surrounding region toward the back- ground rate distribution. The number of aftershocks near the rupture region is found to decay with time as Omori aftershock decay law predicts. The example results dem- onstrate that the rate-and-state fault system earthquakesimulator and the seismicity equations based on the rate- state friction nucleation of earthquake are well posited to characterize the aftershock distribution in regional assess- ments of earthquake probabilities.
基金supported by the National Natural Science Foundation of China(62174086 and 62474096)the Outstanding Youth Foundation of Jiangsu Province(BK20240139).
文摘Gastrointestinal(GI)diseases,especially cancers,are responsible for 25%of global cancer cases and one-third of cancer-related deaths,with treatment costs projected to surpass$21 billion annually by 2030[1,2].Early diagnosis and continuous monitoring of physiological signals are critical for the effective prevention and management of these conditions[3].Since the concept of ingestible electronic pills was first proposed in the 1960s[4]and the first commercially approved device was launched in 2001[5],ongoing technological advances have increasingly demonstrated the promise of wireless ingestible capsules as a minimally invasive platform for personalized gastroenterological care(Table S1 online).
