Heavy-load transfer robots are widely used in automobile production and machinery manufacturing to improve production efficiency.In order to meet the needs of large billet transfer,a 4-DOF transfer robot is designed i...Heavy-load transfer robots are widely used in automobile production and machinery manufacturing to improve production efficiency.In order to meet the needs of large billet transfer,a 4-DOF transfer robot is designed in this paper,which consists of parallel four-bar mechanisms.The Jacobian matrix referring to the mapping matrix from the joint velocity to the operating space velocity of the transfer robot can be solved by the differential-vector method.The mean value of the Jacobian matrix condition number in the workspace is used as the global performance index of the robot velocity and the optimization goal.The constraint condition is established based on the actual working condition.Then the linkage length optimization is carried out to decrease the length of the linkage and to increase the global performance index of velocity.The total length of robot rods is reduced by 6.12%.The global performance index of velocity is improved by 45.15%.Taking the optimized rod length as the mechanism parameter,the distribution of the motion space of the transfer robot is obtained.Finally,the results show that the proposed method for establishing the Jacobian matrix of the lower-mobility robot and for the optimization of the rods based on the velocity global performance index is accurate and effective.The workspace distribution of the robot meets the design requirements.展开更多
During screening operation, blinding or clogging of screen perforations generally occurs to reduce the sieving capacity and efficiency. Recently, the flip-flow screening has been widely recognized as a feasible method...During screening operation, blinding or clogging of screen perforations generally occurs to reduce the sieving capacity and efficiency. Recently, the flip-flow screening has been widely recognized as a feasible method to deal with the problem. In this paper, a novel centralized-driving flip-flow screen(CFS) was developed for the separation of fine and moist coal, and the key structures, namely, a centralized-driving mechanism and a quasi-circle beam mounted with the mat were designed for high reliability and stability. By means of a test on an experimental prototype, the effect of some factors, i.e., initial stretch and hardness of the polyurethane panel, respectively, and the rotation speed of the driving motor on the kinematic characteristic of the screen surface was investigated. Results show that without an initial stretch, the sieve mat generates the largest vibratory amplitude while the slacker the sieve mat initially is, the smaller amplitude it will accomplish. And an increase in the rotation speed could cause a rise in the vibratory amplitude. Unlike the two factors, the hardness does not have a definite effect on the kinematic performance, on which a further study is required. Finally, screening processing on a laboratory prototype was conducted to draw the conclusion that the developed CFS also has a high sieving efficiency for the fine and moist coal.展开更多
A new kind of flexible pneumatic wall-climbing robot,named WALKMAN-I,was proposed. WALKMAN-I is basically composed of a flexible pneumatic actuator (FPA),a flexible pneumatic spherical joint and six suction cups. It h...A new kind of flexible pneumatic wall-climbing robot,named WALKMAN-I,was proposed. WALKMAN-I is basically composed of a flexible pneumatic actuator (FPA),a flexible pneumatic spherical joint and six suction cups. It has many characteristics of low-cost,lightweight,simple structure and good flexibility. Its operating principle was introduced. Then three basic locomotion modes,which are linear motion,curvilinear motion and crossing the orthogonal planes,were presented. The safety conditions of WALKMAN-I were discussed and built. Finally,the control system was designed and experiments were carried out. Experimental results show that WALKMAN-I is able to climb on the vertical wall surface along a straight line or a curved path,and has the ability of crossing orthogonal planes and obstacles. The maximum rotation angle reaches 90°,the maximum velocity reaches 5 mm/s,and the rotation angle and the moving velocity of WALKMAN-I can be easily controlled.展开更多
The ATP synthase （having a typical subunit composition of α3β3γeab2c8-15） employs an intriguing rotary mechanism for the generation of ATP from ADP and Pi, using energy stored in a transmembrane proton gradient. ...The ATP synthase （having a typical subunit composition of α3β3γeab2c8-15） employs an intriguing rotary mechanism for the generation of ATP from ADP and Pi, using energy stored in a transmembrane proton gradient. The conventional rotary model, although being generally accepted, remains difficult to explain certain experimental observations. Here we propose an alterna- tive rotary model for the ATP synthase such that what rotates is the catalytic α3β3 cylinder rather than the central stalk and the membrane-embedded c-ring. Specifically, the membrane translocation of protons would induce a cycled conformational change in the c-ring, leading to a reciprocating motion of the attached central stalk, which in turn drives the unidirectional rotation of the α3β3 cylinder. Such a reciprocating motion-driven rotation mechanism is somehow analogous to the working mechanism of a retractable click ballpoint pen. Our new model not only explains the experimental observations that have been difficult to reconcile with the conventional model but also avoids its theoretical illogicality.展开更多
基金supported by the National Key R&D Program of China(No.2018YFB1307900)the Natural Science Foundation of Shanxi Province(Nos.201901D211009,201901D211010)the Technology In⁃novation Foundation of Shanxi University(No.2019L 0177).
文摘Heavy-load transfer robots are widely used in automobile production and machinery manufacturing to improve production efficiency.In order to meet the needs of large billet transfer,a 4-DOF transfer robot is designed in this paper,which consists of parallel four-bar mechanisms.The Jacobian matrix referring to the mapping matrix from the joint velocity to the operating space velocity of the transfer robot can be solved by the differential-vector method.The mean value of the Jacobian matrix condition number in the workspace is used as the global performance index of the robot velocity and the optimization goal.The constraint condition is established based on the actual working condition.Then the linkage length optimization is carried out to decrease the length of the linkage and to increase the global performance index of velocity.The total length of robot rods is reduced by 6.12%.The global performance index of velocity is improved by 45.15%.Taking the optimized rod length as the mechanism parameter,the distribution of the motion space of the transfer robot is obtained.Finally,the results show that the proposed method for establishing the Jacobian matrix of the lower-mobility robot and for the optimization of the rods based on the velocity global performance index is accurate and effective.The workspace distribution of the robot meets the design requirements.
基金The financial support from the National Natural Science Foundation of China (Nos. 51221462 and 51134022)the Doctoral Programs Foundation of Ministry of Education of China (No. 20120095110001)
文摘During screening operation, blinding or clogging of screen perforations generally occurs to reduce the sieving capacity and efficiency. Recently, the flip-flow screening has been widely recognized as a feasible method to deal with the problem. In this paper, a novel centralized-driving flip-flow screen(CFS) was developed for the separation of fine and moist coal, and the key structures, namely, a centralized-driving mechanism and a quasi-circle beam mounted with the mat were designed for high reliability and stability. By means of a test on an experimental prototype, the effect of some factors, i.e., initial stretch and hardness of the polyurethane panel, respectively, and the rotation speed of the driving motor on the kinematic characteristic of the screen surface was investigated. Results show that without an initial stretch, the sieve mat generates the largest vibratory amplitude while the slacker the sieve mat initially is, the smaller amplitude it will accomplish. And an increase in the rotation speed could cause a rise in the vibratory amplitude. Unlike the two factors, the hardness does not have a definite effect on the kinematic performance, on which a further study is required. Finally, screening processing on a laboratory prototype was conducted to draw the conclusion that the developed CFS also has a high sieving efficiency for the fine and moist coal.
基金Project (50575206) supported by the National Natural Science Foundation of ChinaProject (BX102716) supported by Xinmiao Program of Zhejiang Province, China
文摘A new kind of flexible pneumatic wall-climbing robot,named WALKMAN-I,was proposed. WALKMAN-I is basically composed of a flexible pneumatic actuator (FPA),a flexible pneumatic spherical joint and six suction cups. It has many characteristics of low-cost,lightweight,simple structure and good flexibility. Its operating principle was introduced. Then three basic locomotion modes,which are linear motion,curvilinear motion and crossing the orthogonal planes,were presented. The safety conditions of WALKMAN-I were discussed and built. Finally,the control system was designed and experiments were carried out. Experimental results show that WALKMAN-I is able to climb on the vertical wall surface along a straight line or a curved path,and has the ability of crossing orthogonal planes and obstacles. The maximum rotation angle reaches 90°,the maximum velocity reaches 5 mm/s,and the rotation angle and the moving velocity of WALKMAN-I can be easily controlled.
基金supported by research grants from the National Basic Research Program of China(2012CB917300 to Zengyi Chang and Xinmiao Fu)the National Natural Science Foundation of China(31470766 and 31170738 to ZYC31270804 and 31570778 to Xinmiao Fu)
文摘The ATP synthase （having a typical subunit composition of α3β3γeab2c8-15） employs an intriguing rotary mechanism for the generation of ATP from ADP and Pi, using energy stored in a transmembrane proton gradient. The conventional rotary model, although being generally accepted, remains difficult to explain certain experimental observations. Here we propose an alterna- tive rotary model for the ATP synthase such that what rotates is the catalytic α3β3 cylinder rather than the central stalk and the membrane-embedded c-ring. Specifically, the membrane translocation of protons would induce a cycled conformational change in the c-ring, leading to a reciprocating motion of the attached central stalk, which in turn drives the unidirectional rotation of the α3β3 cylinder. Such a reciprocating motion-driven rotation mechanism is somehow analogous to the working mechanism of a retractable click ballpoint pen. Our new model not only explains the experimental observations that have been difficult to reconcile with the conventional model but also avoids its theoretical illogicality.
