The goal of this paper is to develop a unified online motion generation scheme for quadruped lateral-sequence walk and trot gaits based on a linear model predictive control formulation.Specifically,the dynamics of the...The goal of this paper is to develop a unified online motion generation scheme for quadruped lateral-sequence walk and trot gaits based on a linear model predictive control formulation.Specifically,the dynamics of the linear pendulum model is formulated over a predictive horizon by dimensional analysis.Through gait pattern conversion,the lateral-sequence walk and trot gaits of the quadruped can be regarded as unified biped gaits,allowing the dynamics of the linear inverted pendulum model to serve quadruped motion generation.In addition,a simple linearization of the center of pressure constraints for these quadruped gaits is developed for linear model predictive control problem.Furthermore,the motion generation problem can be solved online by quadratic programming with foothold adaptation.It is demonstrated that the proposed unified scheme can generate stable locomotion online for quadruped lateral-sequence walk and trot gaits,both in simulation and on hardware.The results show significant performance improvements compared to previous work.Moreover,the results also suggest the linearly simplified scheme has the ability to robustness against unexpected disturbances.展开更多
This paper proposes a unified trajectory optimization approach that simultaneously optimizes the trajectory of the center of mass and footholds for legged locomotion.Based on a generic point-mass model,the approach is...This paper proposes a unified trajectory optimization approach that simultaneously optimizes the trajectory of the center of mass and footholds for legged locomotion.Based on a generic point-mass model,the approach is formulated as a nonlinear optimization problem,incorporating constraints such as robot kinematics,dynamics,ground reaction forces,obstacles,and target location.The unified optimization approach can be applied to both long-term motion planning and the reactive online planning through the use of model predictive control,and it incorporates vector field guidance to converge to the long-term planned motion.The effectiveness of the approach is demonstrated through simulations and physical experiments,showing its ability to generate a variety of walking and jumping gaits,as well as transitions between them,and to perform reactive walking in obstructed environments.展开更多
In the era of big data and the Internet of Things,the digital information of athletes is particularly significant in sports competitions.Here,an intelligent self-powered take-off board sensor(TBS)based on triboelectri...In the era of big data and the Internet of Things,the digital information of athletes is particularly significant in sports competitions.Here,an intelligent self-powered take-off board sensor(TBS)based on triboelectric nanogenerator(TENG)with a solid-wooden substrate is provided for precise detection of athletes’take-off status in the sport of triple-jumping,which is sufficient for triplejumping training judgment with a high accuracy of 1 mm.Meanwhile,a foul alarm system and a distance between the athlete’s foot and take-off line(GAP)measurement system are further developed to provide take-off data for athletes and referees.The induced charges are formed by the TBS during taking-off,and then the real-time exercise data is acquired and processed via the test program.This work presents a self-powered sports sensor for intelligent sports monitoring and promotes the application of TENG-based sensors in intelligent sports.展开更多
The theft prevention for cultural relics in museums,field excavation sites,and temporary exhibition events is of extreme importance.However,traditional anti-theft technologies such as infrared monitoring and radio fre...The theft prevention for cultural relics in museums,field excavation sites,and temporary exhibition events is of extreme importance.However,traditional anti-theft technologies such as infrared monitoring and radio frequency identification are highly costly,power-consuming,and easy to break.Here,a transparent,ultrathin,and flexible triboelectric sensor(TUFS)with a simple and low-cost method is proposed.With a thickness,weight,and transmittance of 92μm,0.12 g,and 89.4%,the TUFS manifests superb concealment.Benefiting from the characteristic of triboelectric nanogenerators,the TUFS responds effectively to common cultural-relic materials.Moreover,distinguished electrical responses can be obtained even for very small weights(10 g)and areas(1 cm^(2)),proving the sensitivity and wide range of use of the TUFS.Finally,we construct a concealed cultural-relic anti-theft system that enables real-time alarming and accurate positioning of cultural relics,which is expected to strengthen the security level of the existing museum anti-theft systems.展开更多
Solid-state Li metal batteries with solid electrolytes have built a potential way to solve the safety and low energy density problems of current commercial Li-ion batteries with liquid electrolyte.As a key component o...Solid-state Li metal batteries with solid electrolytes have built a potential way to solve the safety and low energy density problems of current commercial Li-ion batteries with liquid electrolyte.As a key component of solid-state Li metal batteries,solid electrolytes require high ionic conductivities and good mechanical properties.We have designed a composite solid electrolyte(CSE)consisting of poly(vinylidene fluoride-hexafluoropropylene)(PVDF-HFP)-Li_(6.5)La_(3)Zr_(1.5)Ta_(0.5)O_(12)(LLZTO)-succinonitrile(SN)and Li bis(trifluoromethylsulphonyl)imide(LiTFSI).The PVDF-HFP-based porous matrix made by electrospinning ensures good mechanical properties of the electrolyte membrane,and the large proportion of SN filling material makes the electrolyte membrane have an ionic conductivity of 1.11 mS·cm^(–1)without the addition of liquid electrolyte.The symmetric battery assembled with CSE can be cycled stably for more than 600 h,and the LiFePO4|CSE|Li full battery can also be cycled stably for more than 200 cycles.In addition to Li metal batteries,Li-O_(2)and Li-CO_(2)batteries that use CSE as electrolytes also have good performances,reflecting the universality of CSE.CSE does not only guarantee good mechanical properties but also obtain a high ionic conductivity.This design provides a new idea for the commercial application of polymer-based solid batteries.展开更多
基金supported by the National Natural Science Foundation of China(Nos.52305072 and 52122503)Natural Science Foundation of Hebei Province of China(No.E2022203095)+2 种基金University-Industry Collaborative Education Program(No.220603936245709)Cultivation Project for Basic Research and Innovation of Yanshan University(No.2021LGQN004)henzhen Special Fund for Future Industrial Development(No.KJZD20230923114222045).
文摘The goal of this paper is to develop a unified online motion generation scheme for quadruped lateral-sequence walk and trot gaits based on a linear model predictive control formulation.Specifically,the dynamics of the linear pendulum model is formulated over a predictive horizon by dimensional analysis.Through gait pattern conversion,the lateral-sequence walk and trot gaits of the quadruped can be regarded as unified biped gaits,allowing the dynamics of the linear inverted pendulum model to serve quadruped motion generation.In addition,a simple linearization of the center of pressure constraints for these quadruped gaits is developed for linear model predictive control problem.Furthermore,the motion generation problem can be solved online by quadratic programming with foothold adaptation.It is demonstrated that the proposed unified scheme can generate stable locomotion online for quadruped lateral-sequence walk and trot gaits,both in simulation and on hardware.The results show significant performance improvements compared to previous work.Moreover,the results also suggest the linearly simplified scheme has the ability to robustness against unexpected disturbances.
基金supported by the Natural Science Foundation of Hebei Province of China(no.E2022203095)Cultivation Project for Basic Research and Innovation of Yanshan University(no.2021LGQN004)National Natural Science Foundation of China(no.51905465 and No.52122503).
文摘This paper proposes a unified trajectory optimization approach that simultaneously optimizes the trajectory of the center of mass and footholds for legged locomotion.Based on a generic point-mass model,the approach is formulated as a nonlinear optimization problem,incorporating constraints such as robot kinematics,dynamics,ground reaction forces,obstacles,and target location.The unified optimization approach can be applied to both long-term motion planning and the reactive online planning through the use of model predictive control,and it incorporates vector field guidance to converge to the long-term planned motion.The effectiveness of the approach is demonstrated through simulations and physical experiments,showing its ability to generate a variety of walking and jumping gaits,as well as transitions between them,and to perform reactive walking in obstructed environments.
基金supported by the National Natural Science Foundation of China(No.61503051).
文摘In the era of big data and the Internet of Things,the digital information of athletes is particularly significant in sports competitions.Here,an intelligent self-powered take-off board sensor(TBS)based on triboelectric nanogenerator(TENG)with a solid-wooden substrate is provided for precise detection of athletes’take-off status in the sport of triple-jumping,which is sufficient for triplejumping training judgment with a high accuracy of 1 mm.Meanwhile,a foul alarm system and a distance between the athlete’s foot and take-off line(GAP)measurement system are further developed to provide take-off data for athletes and referees.The induced charges are formed by the TBS during taking-off,and then the real-time exercise data is acquired and processed via the test program.This work presents a self-powered sports sensor for intelligent sports monitoring and promotes the application of TENG-based sensors in intelligent sports.
基金the National Natural Science Foundation of China(No.61503051).
文摘The theft prevention for cultural relics in museums,field excavation sites,and temporary exhibition events is of extreme importance.However,traditional anti-theft technologies such as infrared monitoring and radio frequency identification are highly costly,power-consuming,and easy to break.Here,a transparent,ultrathin,and flexible triboelectric sensor(TUFS)with a simple and low-cost method is proposed.With a thickness,weight,and transmittance of 92μm,0.12 g,and 89.4%,the TUFS manifests superb concealment.Benefiting from the characteristic of triboelectric nanogenerators,the TUFS responds effectively to common cultural-relic materials.Moreover,distinguished electrical responses can be obtained even for very small weights(10 g)and areas(1 cm^(2)),proving the sensitivity and wide range of use of the TUFS.Finally,we construct a concealed cultural-relic anti-theft system that enables real-time alarming and accurate positioning of cultural relics,which is expected to strengthen the security level of the existing museum anti-theft systems.
基金the support from the National Key R&D Program of China(No.2021YFA1501101)the National Natural Science Foundation of China(No.21771156)+1 种基金the National Natural Science Foundation of China/RGC Joint Research Scheme(No.N_PolyU502/21)the funding for Projects of Strategic Importance of The Hong Kong Polytechnic University(Project Code:1-ZE2V).
文摘Solid-state Li metal batteries with solid electrolytes have built a potential way to solve the safety and low energy density problems of current commercial Li-ion batteries with liquid electrolyte.As a key component of solid-state Li metal batteries,solid electrolytes require high ionic conductivities and good mechanical properties.We have designed a composite solid electrolyte(CSE)consisting of poly(vinylidene fluoride-hexafluoropropylene)(PVDF-HFP)-Li_(6.5)La_(3)Zr_(1.5)Ta_(0.5)O_(12)(LLZTO)-succinonitrile(SN)and Li bis(trifluoromethylsulphonyl)imide(LiTFSI).The PVDF-HFP-based porous matrix made by electrospinning ensures good mechanical properties of the electrolyte membrane,and the large proportion of SN filling material makes the electrolyte membrane have an ionic conductivity of 1.11 mS·cm^(–1)without the addition of liquid electrolyte.The symmetric battery assembled with CSE can be cycled stably for more than 600 h,and the LiFePO4|CSE|Li full battery can also be cycled stably for more than 200 cycles.In addition to Li metal batteries,Li-O_(2)and Li-CO_(2)batteries that use CSE as electrolytes also have good performances,reflecting the universality of CSE.CSE does not only guarantee good mechanical properties but also obtain a high ionic conductivity.This design provides a new idea for the commercial application of polymer-based solid batteries.
