This paper addresses a master-slave synchro- nization strategy for complex dynamic systems based on feedback control. This strategy is applied to 3-DOF pla- nar manipulators in order to obtain synchronization in such ...This paper addresses a master-slave synchro- nization strategy for complex dynamic systems based on feedback control. This strategy is applied to 3-DOF pla- nar manipulators in order to obtain synchronization in such complicated as chaotic motions of end-effectors. A chaotic curve is selected from Duffing equation as the trajectory of master end-effector and a piecewise approximation method is proposed to accurately represent this chaotic trajectory of end-effectors. The dynamical equations of master-slave manipulators with synchronization controller are derived, and the Lyapunov stability theory is used to determine the stability of this controlled synchronization system. In numer- ical experiments, the synchronous motions of end-effectors as well as three joint angles and torques of master-slave manipulators are studied under the control of the proposed synchronization strategy. It is found that the positive gain matrix affects the implementation of synchronization con- trol strategy. This synchronization control strategy proves the synchronization＇s feasibility and controllability for com- plicated motions generated by master-slave manipulators.展开更多
This paper investigates the motion planning of redundant free-floating manipulators with seven prismatic joints. On the earth, prismatic-jointed manipulators could only position their end-effectors in a desired way. H...This paper investigates the motion planning of redundant free-floating manipulators with seven prismatic joints. On the earth, prismatic-jointed manipulators could only position their end-effectors in a desired way. However, in space, the end-effectors of free-floating manipulators can achieve both the desired orientation and desired position due to the dynamical coupling between manipulator and satellite movement, which is formally expressed by linear and angular momentum conservation laws. In this study, a tractable algorithm particle swarm optimization combined with differential evolution （PSODE） is provided to deal with the motion planning of redundant free-floating prismatic-jointed manipulators, which could avoid the pseudo inverse of the Jacobian matrix. The polynomial functions, as argument in sine functions are used to specify the joint paths. The co- efficients of the polynomials are optimized to achieve the desired end-effector orientation and position, and simulta- neously minimize the unit-mass-kinetic energy using the redundancy. Relevant simulations prove that this method pro- vides satisfactory smooth paths for redundant free-floating prismatic-jointed manipulators. This study could help to recognize the advantages of redundant prismatic-jointed space manipulators.展开更多
Objective： One of the most common joint dislocations presented to the emergency department （ED） is anterior shoulder dislocation （ASD）. Various techniques for the treatment of this abnormality have been suggested...Objective： One of the most common joint dislocations presented to the emergency department （ED） is anterior shoulder dislocation （ASD）. Various techniques for the treatment of this abnormality have been suggested. In this study, we evaluated the efficacy and success rate of modified scapular manipulation （MSM） as a painless procedure compared to traction-countertraction （TCT） for reduction of ASD. Methods： Patients with ASD who were presented to ED of Baqiyatallah Hospital, Tehran during 2011 were included. They were randomly divided into MSM group or TCT group and then pain at reduction, time of reduction, duration of hospitalization, and success rate were compared. In TCT group, reduction was performed using sedative and antipain medications. Results： Ninety seven patients （81.6% male） with a mean age of 34.15 years±13.48 years were studied. The reduction time between both groups showed a significant difference （470.88 seconds±227.59 seconds for TCT group, 79.35 seconds±82.49 seconds for MSM group, P〈0.001）. The success rate in MSM group in the first and second effort were 89% and 97% whereas 73% and 100% in the TCT group respectively （P〈0.001）. Conclusion： It seems that the manipulation technique can be more successful than the TCT method at the first effort whilst the second effort has the opposite results. Also MSM can be safer, cheaper and more acceptable for patients than TCT as a standard traditional method.展开更多
基金supported by the Key Project of Chinese Ministry of Education(108037)the National Natural Science Foundation of China(10402008 and 50535010)
文摘This paper addresses a master-slave synchro- nization strategy for complex dynamic systems based on feedback control. This strategy is applied to 3-DOF pla- nar manipulators in order to obtain synchronization in such complicated as chaotic motions of end-effectors. A chaotic curve is selected from Duffing equation as the trajectory of master end-effector and a piecewise approximation method is proposed to accurately represent this chaotic trajectory of end-effectors. The dynamical equations of master-slave manipulators with synchronization controller are derived, and the Lyapunov stability theory is used to determine the stability of this controlled synchronization system. In numer- ical experiments, the synchronous motions of end-effectors as well as three joint angles and torques of master-slave manipulators are studied under the control of the proposed synchronization strategy. It is found that the positive gain matrix affects the implementation of synchronization con- trol strategy. This synchronization control strategy proves the synchronization＇s feasibility and controllability for com- plicated motions generated by master-slave manipulators.
基金supported by the National Natural Science Foundation of China (11072122)
文摘This paper investigates the motion planning of redundant free-floating manipulators with seven prismatic joints. On the earth, prismatic-jointed manipulators could only position their end-effectors in a desired way. However, in space, the end-effectors of free-floating manipulators can achieve both the desired orientation and desired position due to the dynamical coupling between manipulator and satellite movement, which is formally expressed by linear and angular momentum conservation laws. In this study, a tractable algorithm particle swarm optimization combined with differential evolution （PSODE） is provided to deal with the motion planning of redundant free-floating prismatic-jointed manipulators, which could avoid the pseudo inverse of the Jacobian matrix. The polynomial functions, as argument in sine functions are used to specify the joint paths. The co- efficients of the polynomials are optimized to achieve the desired end-effector orientation and position, and simulta- neously minimize the unit-mass-kinetic energy using the redundancy. Relevant simulations prove that this method pro- vides satisfactory smooth paths for redundant free-floating prismatic-jointed manipulators. This study could help to recognize the advantages of redundant prismatic-jointed space manipulators.
文摘Objective： One of the most common joint dislocations presented to the emergency department （ED） is anterior shoulder dislocation （ASD）. Various techniques for the treatment of this abnormality have been suggested. In this study, we evaluated the efficacy and success rate of modified scapular manipulation （MSM） as a painless procedure compared to traction-countertraction （TCT） for reduction of ASD. Methods： Patients with ASD who were presented to ED of Baqiyatallah Hospital, Tehran during 2011 were included. They were randomly divided into MSM group or TCT group and then pain at reduction, time of reduction, duration of hospitalization, and success rate were compared. In TCT group, reduction was performed using sedative and antipain medications. Results： Ninety seven patients （81.6% male） with a mean age of 34.15 years±13.48 years were studied. The reduction time between both groups showed a significant difference （470.88 seconds±227.59 seconds for TCT group, 79.35 seconds±82.49 seconds for MSM group, P〈0.001）. The success rate in MSM group in the first and second effort were 89% and 97% whereas 73% and 100% in the TCT group respectively （P〈0.001）. Conclusion： It seems that the manipulation technique can be more successful than the TCT method at the first effort whilst the second effort has the opposite results. Also MSM can be safer, cheaper and more acceptable for patients than TCT as a standard traditional method.
