Robot hands have been developing during the last few decades. There are many mechanical structures and analyti?cal methods for di erent hands. But many tough problems still limit robot hands to apply in homelike envir...Robot hands have been developing during the last few decades. There are many mechanical structures and analyti?cal methods for di erent hands. But many tough problems still limit robot hands to apply in homelike environment. The ability of grasping objects covering a large range of sizes and various shapes is fundamental for a home service robot to serve people better. In this paper, a new grasping mode based on a novel sucked?type underactuated(STU) hand is proposed. By combining the flexibility of soft material and the e ect of suction cups, the STU hand can grasp objects with a wide range of sizes, shapes and materials. Moreover, the new grasping mode is suitable for some situations where the force closure is failure. In this paper, we deduce the e ective range of sizes of objects which our hand using the new grasping mode can grasp. Thanks to the new grasping mode, the ratio of grasping size between the biggest object and the smallest is beyond 40, which makes it possible for our robot hand to grasp diverse objects in our daily life. For example, the STU hand can grasp a soccer(220 mm diameter, 420 g) and a fountain pen(9 mm diameter, 9 g). What’s more, we use the rigid body equilibrium conditions to analysis the force condition. Experiment evaluates the high load capacity, stability of the new grasping mode and displays the versatility of the STU hand. The STU hand has a wide range of applications especially in unstructured environment.展开更多
A grasping force control strategy is proposed in order to complete various fine manipulations by using anthropomorphic prosthetic hand.The position-based impedance control and force-tracking impedance control are used...A grasping force control strategy is proposed in order to complete various fine manipulations by using anthropomorphic prosthetic hand.The position-based impedance control and force-tracking impedance control are used in free and constraint spaces,respectively.The fuzzy observer is adopted in transition in order to switch control mode.Two control modes use one position-based impedance controller.In order to achieve grasping force track,reference force is added to the impedance controller in the constraint space.Trajectory tracking in free space and torque tracking in constrained space are realized,and reliability of mode switch and stability of system are achieved.An adaptive sliding mode friction compensation method is proposed.This method makes use of terminal sliding mode idea to design sliding mode function,which makes the tracking error converge to zero in finite time and avoids the problem of conventional sliding surface that tracking error cannot converge to zero.Based on the characteristic of the exponential form friction,the sliding mode control law including the estimation of friction parameter is obtained through terminal sliding mode idea,and the online parameter update laws are obtained based on Lyapunov stability theorem.The experiments on the HIT Prosthetic Hand IV are carried out to evaluate the grasping force control strategy,and the experiment results verify the effectiveness of this control strategy.展开更多
基金National Natural Science Foundation of China(Grant Nos.U1613216,61573333)
文摘Robot hands have been developing during the last few decades. There are many mechanical structures and analyti?cal methods for di erent hands. But many tough problems still limit robot hands to apply in homelike environment. The ability of grasping objects covering a large range of sizes and various shapes is fundamental for a home service robot to serve people better. In this paper, a new grasping mode based on a novel sucked?type underactuated(STU) hand is proposed. By combining the flexibility of soft material and the e ect of suction cups, the STU hand can grasp objects with a wide range of sizes, shapes and materials. Moreover, the new grasping mode is suitable for some situations where the force closure is failure. In this paper, we deduce the e ective range of sizes of objects which our hand using the new grasping mode can grasp. Thanks to the new grasping mode, the ratio of grasping size between the biggest object and the smallest is beyond 40, which makes it possible for our robot hand to grasp diverse objects in our daily life. For example, the STU hand can grasp a soccer(220 mm diameter, 420 g) and a fountain pen(9 mm diameter, 9 g). What’s more, we use the rigid body equilibrium conditions to analysis the force condition. Experiment evaluates the high load capacity, stability of the new grasping mode and displays the versatility of the STU hand. The STU hand has a wide range of applications especially in unstructured environment.
基金Project(2009AA043803) supported by the National High Technology Research and Development Program of China Project (SKLRS200901B) supported by Self-Planned Task of State Key Laboratory of Robotics and System (Harbin Institute of Technology),ChinaProject (NCET-09-0056) supported by Program for New Century Excellent Talents in Universities of China
文摘A grasping force control strategy is proposed in order to complete various fine manipulations by using anthropomorphic prosthetic hand.The position-based impedance control and force-tracking impedance control are used in free and constraint spaces,respectively.The fuzzy observer is adopted in transition in order to switch control mode.Two control modes use one position-based impedance controller.In order to achieve grasping force track,reference force is added to the impedance controller in the constraint space.Trajectory tracking in free space and torque tracking in constrained space are realized,and reliability of mode switch and stability of system are achieved.An adaptive sliding mode friction compensation method is proposed.This method makes use of terminal sliding mode idea to design sliding mode function,which makes the tracking error converge to zero in finite time and avoids the problem of conventional sliding surface that tracking error cannot converge to zero.Based on the characteristic of the exponential form friction,the sliding mode control law including the estimation of friction parameter is obtained through terminal sliding mode idea,and the online parameter update laws are obtained based on Lyapunov stability theorem.The experiments on the HIT Prosthetic Hand IV are carried out to evaluate the grasping force control strategy,and the experiment results verify the effectiveness of this control strategy.
