Design of 3D-printed Cable Driven Humanoid Hand Based on Bidirectional Elastomeric Passive Transmission

Motion control of the human hand is the most complex part of the human body.It has always been a challenge for a good balance between the cost,weight,responding speed,grasping force,finger extension,and dexterity of prosthetic hand.To solve these issues,a 3D-printed cable driven humanoid hand based on bidirectional elastomeric passive transmission(BEPT)is designed in this paper.A semi-static model of BEPT is investigated based on energy conservation law to analyze the mechanical properties of BEPT and a dynamical simulation of finger grasping is conducted.For a good imitation of human hand and an excellent grasping performance,specific BEPT is selected according to human finger grasping experiments.The advantage of BEPT based humanoid hand is that a good balance between the price and performance of the humanoid hand is achieved.Experiments proved that the designed prosthetic hand’s single fingertip force can reach 33 N and the fastest fingertip grasping speed realized 0.6 s/180°.It also has a good force compliance effect with only 430g’s weight.It can not only grab fragile objects like raw eggs and paper cup,but also achieve strong grasping force to damage metal cans.This humanoid hand has considerable application prospects in artificial prosthesis,human-computer interaction,and robot operation.

An Asymmetric Controlled Bidirectional Quantum State Transmission Protocol

In this paper,we propose an asymmetric controlled bidirectional transmission protocol.In the protocol,by using the thirteen-qubit entangled state as the quantum channel,Alice can realize the transmission of a two-qubit equatorial state for Bob and Bob can transmit a four-qubit equatorial state for Alice under the control of Charlie.Firstly,we give the construction of the quantum channel,which can be done by performing several H and CNOT operations.Secondly,through implementing the appropriate measurements and the corresponding recovery operations,the desired states can be transmitted simultaneously,securely and deterministically.Finally,we analyze the performance of the protocol,including the efficiency,the necessary operations and the classical communication costs.And then,we describe some comparisons with other protocols.Since our protocol does not require auxiliary particles and additional operations,the classic communication costs less while achieving the multi-particle bidirectional transmission,so the overall performance of the protocol is better.

One-dimensional PT-symmetric acoustic heterostructure

The explorations of parity-time(PT)-symmetric acoustics have resided at the frontier in physics,and the pre-existing accessing of exceptional points typically depends on Fabry-Perot resonances of the coupling interlayer sandwiched between balanced gain and loss components.Nevertheless,the concise PT-symmetric acoustic heterostructure,eliminating extra interactions caused by the interlayer,has not been researched in depth.Here we derive the generalized unitary relation for one-dimensional(1D)PT-symmetric heterostructure of arbitrary complexity,and demonstrate four disparate patterns of anisotropic transmission resonances(ATRs)accompanied by corresponding spontaneous phase transitions.As a special case of ATR,the occasional bidirectional transmission resonance reconsolidates the ATR frequencies that split when waves incident from opposite directions,whose spatial profiles distinguish from a unitary structure.The derived theoretical relation can serve as a predominant signature for the presence of PT symmetry and PT-symmetry-breaking transition,which may provide substantial support for the development of prototype devices with asymmetric acoustic responses.