The modelling and simulation of deformable objects is a challenging topic in the field of haptic rendering between human and virtual environment.In this paper,a novel and efficient layered rhombus-chain-connected hapt...The modelling and simulation of deformable objects is a challenging topic in the field of haptic rendering between human and virtual environment.In this paper,a novel and efficient layered rhombus-chain-connected haptic deformation model based on physics is proposed for an excellent haptic rendering.During the modelling,the accumulation of relative displacements in every chain structure unit in each layer is equal to the deformation on the virtual object surface,and the resultant force of corresponding springs is equivalent to the external force.The layered rhombus-chain-connected model is convenient and fast to calculate,and can satisfy real-time requirement due to its simple nature.Simulation experiments in virtual human liver based on the proposed model are conducted,and the results demonstrate that our model provides stable and realistic haptic feeling in real time.Meanwhile,the display result is vivid.展开更多
The principle of the two carriers contributing to carry the pixel signal charges is firstly presented,and then the bipolar junction photogate transistor(BJPT)with high performance is proposed for the CMOS image sensor...The principle of the two carriers contributing to carry the pixel signal charges is firstly presented,and then the bipolar junction photogate transistor(BJPT)with high performance is proposed for the CMOS image sensor.The numerical analytical model of the photo-charge transfer for the bipolar junction photogate is established in detail. Some numerical simulations are obtained under 0.6 μm CMOS process,which show that its readout rate increases exponentially with the increase of the photo-charge at applied voltage.展开更多
In the one-gravity environment on the ground, the simulation of the contact process of two flying objects in the zero-gravity environment of space has been a challenging issue since humans first explored space by flyi...In the one-gravity environment on the ground, the simulation of the contact process of two flying objects in the zero-gravity environment of space has been a challenging issue since humans first explored space by flying objects. Hardware-in-the-loop （HIL） simulation is an important and effective method to test the usability, reliability, and safety of real docking mechanisms in space. There are four main issues for HIL simulation systems： Design of simulators capable of high frequency response, high motion precision, high velocity, and rapid acceleration; compensation for simulation distortion; design of a control model for the HIL simulation process; and experimental verification. Here, we propose a novel HIL simulator system with a 6-DOF 3-3 perpendicular parallel mechanism and a 3-DOF 3-PRS parallel mechanism; discover the principle of simulation distortion; present distortion compensation models for the force measurement system, dynamic response, and structural dynamics of the simulator; and provide a control model for the HIL simulation process. Two kinds of experiments were performed on the pas- sive-undamped elastic rod and the docking mechanisms to test their performances and to verify the effectiveness and usability of the HIL simulator. The HIL simulation system proposed in this paper is useful for developing space docking, berthing, refu- eling, repairing, upgrading, transporting, and rescuing technologies.展开更多
基金Supported by the National High Technology Research and Development Programme of China(2013AA010803,2009AA01Z311,2009AA01Z314)the National Natural Science Foundation of China(61304205,61075068,61203316)+1 种基金the open funding project of State Key Laboratory of Virtual Reality Technology and Systems,Beihang University,Jiangsu Ordinary University Science Research Project(11KJB460006)Innovation and Entrepreneurship Training Project of College Students(201210300022,12CX023,201310300092)
文摘The modelling and simulation of deformable objects is a challenging topic in the field of haptic rendering between human and virtual environment.In this paper,a novel and efficient layered rhombus-chain-connected haptic deformation model based on physics is proposed for an excellent haptic rendering.During the modelling,the accumulation of relative displacements in every chain structure unit in each layer is equal to the deformation on the virtual object surface,and the resultant force of corresponding springs is equivalent to the external force.The layered rhombus-chain-connected model is convenient and fast to calculate,and can satisfy real-time requirement due to its simple nature.Simulation experiments in virtual human liver based on the proposed model are conducted,and the results demonstrate that our model provides stable and realistic haptic feeling in real time.Meanwhile,the display result is vivid.
文摘The principle of the two carriers contributing to carry the pixel signal charges is firstly presented,and then the bipolar junction photogate transistor(BJPT)with high performance is proposed for the CMOS image sensor.The numerical analytical model of the photo-charge transfer for the bipolar junction photogate is established in detail. Some numerical simulations are obtained under 0.6 μm CMOS process,which show that its readout rate increases exponentially with the increase of the photo-charge at applied voltage.
基金supported by the National Basic Research Program of China(“973”Project)(Grant No.2013CB035501)the National Natural Science Foundation of China(Grant Nos.51335007&61473187)
文摘In the one-gravity environment on the ground, the simulation of the contact process of two flying objects in the zero-gravity environment of space has been a challenging issue since humans first explored space by flying objects. Hardware-in-the-loop （HIL） simulation is an important and effective method to test the usability, reliability, and safety of real docking mechanisms in space. There are four main issues for HIL simulation systems： Design of simulators capable of high frequency response, high motion precision, high velocity, and rapid acceleration; compensation for simulation distortion; design of a control model for the HIL simulation process; and experimental verification. Here, we propose a novel HIL simulator system with a 6-DOF 3-3 perpendicular parallel mechanism and a 3-DOF 3-PRS parallel mechanism; discover the principle of simulation distortion; present distortion compensation models for the force measurement system, dynamic response, and structural dynamics of the simulator; and provide a control model for the HIL simulation process. Two kinds of experiments were performed on the pas- sive-undamped elastic rod and the docking mechanisms to test their performances and to verify the effectiveness and usability of the HIL simulator. The HIL simulation system proposed in this paper is useful for developing space docking, berthing, refu- eling, repairing, upgrading, transporting, and rescuing technologies.
