The crystal structure,martensitic transformation and magnetocaloric effect have been studied in all-d-metal Ni35Co15Mn33Fe2Ti15alloy ribbons with different wheel speeds(15 m/s(S15),30 m/s(S30),and 45 m/s(S45)).All thr...The crystal structure,martensitic transformation and magnetocaloric effect have been studied in all-d-metal Ni35Co15Mn33Fe2Ti15alloy ribbons with different wheel speeds(15 m/s(S15),30 m/s(S30),and 45 m/s(S45)).All three ribbons crystalize in B2-ordered structure at room temperature with crystal constants of 5.893(2)A,5.898(4)A,and5.898(6)A,respectively.With the increase of wheel speed,the martensitic transformation temperature decreases from230 K to 210 K,the Curie temperature increases slightly from 371 K to 378 K.At the same time,magnetic entropy change(△Sm)is also enhanced,as well as refrigeration capacity(RC).The maximum△Sm of 15.6(39.7)J/kg·K and RC of85.5(212.7)J/kg under?H=20(50)k Oe(1 Oe=79.5775 A·m^(-1))appear in S45.The results indicate that the ribbons could be the candidate for solid-state magnetic refrigeration materials.展开更多
In order to improve the robot's obstacle-climbing capability,a new bionic deformable planetary-wheeled robot based on the modular design was proposed. It mainly consisted of planetary wheels to surmount obstacles,...In order to improve the robot's obstacle-climbing capability,a new bionic deformable planetary-wheeled robot based on the modular design was proposed. It mainly consisted of planetary wheels to surmount obstacles,a transformable chassis and an averagely segmentation body. The mobile system of the robot was mainly designed while considering the chassis transformability; a deformable four-bar linkage was adopted,which could realize the robot's wheelbase conversion from storing to driving. To improve the wheels' capability of obstacle-climbing,planetary wheels were adopted. At the same time,passive adaptation to various terrains was considered in the body design and an averaging system was included,which ensured that the planetary wheels could land simultaneously in rugged grounds. The robot's steering mode was analyzed and its kinematics model was built,which provided the theoretical evidence for studying the robot motion control.展开更多
Most existing biped robots can only walk with their feet or move by wheels.To combine the best of both worlds,this paper introduces the dynamic wheeled control including wheeled locomotion and in-situ wheel-to-foot(Wt...Most existing biped robots can only walk with their feet or move by wheels.To combine the best of both worlds,this paper introduces the dynamic wheeled control including wheeled locomotion and in-situ wheel-to-foot(WtF)transformation of a full-sized wheel-biped transformable robot SR600-II.It can traverse on flat surfaces by wheels and transform to footed stance through its switching modules when facing obstacles.For wheeled locomotion,the kinematics considering upper-body lumped center-of-mass(CoM)constraint is first derived.Then,the dynamics of wheeled locomotion is modeled as a wheeled inverted pendulum(WIP)with variables related to the pose of upper body.After that,a parameter-varying linear quadratic regulator(LQR)controller is utilized to enable dynamic wheeled locomotion.For WtF transformation,the WtF balance constraints are first revealed.Then,a WtF transformation strategy is proposed to tackle the problem when robot transforms from wheeled balance state to in-situ biped stance state.It enables the robot to pass by the transition stages in which both wheels and feet touch the ground and to maintain its balance at the same time.Simulations and experiments on the SR600-II prototype have validated the efficacy of proposed dynamic wheeled control strategies for both wheeled locomotion and in-situ WtF transformation.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.52001102 and 51771003)。
文摘The crystal structure,martensitic transformation and magnetocaloric effect have been studied in all-d-metal Ni35Co15Mn33Fe2Ti15alloy ribbons with different wheel speeds(15 m/s(S15),30 m/s(S30),and 45 m/s(S45)).All three ribbons crystalize in B2-ordered structure at room temperature with crystal constants of 5.893(2)A,5.898(4)A,and5.898(6)A,respectively.With the increase of wheel speed,the martensitic transformation temperature decreases from230 K to 210 K,the Curie temperature increases slightly from 371 K to 378 K.At the same time,magnetic entropy change(△Sm)is also enhanced,as well as refrigeration capacity(RC).The maximum△Sm of 15.6(39.7)J/kg·K and RC of85.5(212.7)J/kg under?H=20(50)k Oe(1 Oe=79.5775 A·m^(-1))appear in S45.The results indicate that the ribbons could be the candidate for solid-state magnetic refrigeration materials.
基金National Natural Science Foundation of China(No.51305254)the Shanghai University of Engineering Science High Level Project to Cultivate Special,China(No.2012gp05)the 2012 National College Students' Innovation and Entrepreneurship Training Program,China(No.201210856001)
文摘In order to improve the robot's obstacle-climbing capability,a new bionic deformable planetary-wheeled robot based on the modular design was proposed. It mainly consisted of planetary wheels to surmount obstacles,a transformable chassis and an averagely segmentation body. The mobile system of the robot was mainly designed while considering the chassis transformability; a deformable four-bar linkage was adopted,which could realize the robot's wheelbase conversion from storing to driving. To improve the wheels' capability of obstacle-climbing,planetary wheels were adopted. At the same time,passive adaptation to various terrains was considered in the body design and an averaging system was included,which ensured that the planetary wheels could land simultaneously in rugged grounds. The robot's steering mode was analyzed and its kinematics model was built,which provided the theoretical evidence for studying the robot motion control.
文摘Most existing biped robots can only walk with their feet or move by wheels.To combine the best of both worlds,this paper introduces the dynamic wheeled control including wheeled locomotion and in-situ wheel-to-foot(WtF)transformation of a full-sized wheel-biped transformable robot SR600-II.It can traverse on flat surfaces by wheels and transform to footed stance through its switching modules when facing obstacles.For wheeled locomotion,the kinematics considering upper-body lumped center-of-mass(CoM)constraint is first derived.Then,the dynamics of wheeled locomotion is modeled as a wheeled inverted pendulum(WIP)with variables related to the pose of upper body.After that,a parameter-varying linear quadratic regulator(LQR)controller is utilized to enable dynamic wheeled locomotion.For WtF transformation,the WtF balance constraints are first revealed.Then,a WtF transformation strategy is proposed to tackle the problem when robot transforms from wheeled balance state to in-situ biped stance state.It enables the robot to pass by the transition stages in which both wheels and feet touch the ground and to maintain its balance at the same time.Simulations and experiments on the SR600-II prototype have validated the efficacy of proposed dynamic wheeled control strategies for both wheeled locomotion and in-situ WtF transformation.
