A two-step high-precision Time-to-Digital Converter(TDC),integrated with a Single-Photon Avalanche Diode(SPAD),used for Time-Of-Flight(TOF)application,has been developed and tested.Time interval measurement is perform...A two-step high-precision Time-to-Digital Converter(TDC),integrated with a Single-Photon Avalanche Diode(SPAD),used for Time-Of-Flight(TOF)application,has been developed and tested.Time interval measurement is performed by the coarse counter and fine interpolator,which are utilized to measure the total periods and the residue time of the reference clock,respectively.Following a detail analysis of time precision and clock jitter in the two-step structure,the prototype TDC fabricated in GSMC 1P6M 0.18μm CMOS Image Sensor(CIS)technology exhibits a Single-Shot Precision(SSP)of 11.415 ps and a dynamic range of 216.7 ns.In addition,a pixel of the chip occupies 100μm×100μm,and the measured Integral Nonlinearity(INL)and Differential Nonlinearity(DNL)are better than±0.88 LSB and±0.67 LSB,respectively.Meanwhile,the overall power consumption of the chip is 35 mW at 1.8 V power supply.Combined with these characteristics,the designed chip is suitable for TOF-based ranging applications.展开更多
A real-time non-uniform rational B-spline （NURBS） surface interpolator is proposed and 5-axis machining method with a flat-end cutter is discussed. With the Taylor expansion and the coordinate transformation, the al...A real-time non-uniform rational B-spline （NURBS） surface interpolator is proposed and 5-axis machining method with a flat-end cutter is discussed. With the Taylor expansion and the coordinate transformation, the algorithms of NURBS interpolation, cutter effective machining radius, cutter offsetting and.inverse kinematics are deduced and implemented, respectively. Different from the conventional free-form surface machining, the proposed interpolator can real-time generate the motion commands of computer numerical control （CNC） machines with CC feedrate, rather than that of CL. An example part surface is demonstrated and the results of simulation show that the proposed method can be applied in actual 5-axis surface machining.展开更多
基金National Natural Science Foundation of China(61774129,61827812,61704145)Hunan Science and Technology Department Huxiang High-level Talent Gathering Project(2019RS1037)Changsha Science and Technology Plan Key Projects(kq1801035)。
文摘A two-step high-precision Time-to-Digital Converter(TDC),integrated with a Single-Photon Avalanche Diode(SPAD),used for Time-Of-Flight(TOF)application,has been developed and tested.Time interval measurement is performed by the coarse counter and fine interpolator,which are utilized to measure the total periods and the residue time of the reference clock,respectively.Following a detail analysis of time precision and clock jitter in the two-step structure,the prototype TDC fabricated in GSMC 1P6M 0.18μm CMOS Image Sensor(CIS)technology exhibits a Single-Shot Precision(SSP)of 11.415 ps and a dynamic range of 216.7 ns.In addition,a pixel of the chip occupies 100μm×100μm,and the measured Integral Nonlinearity(INL)and Differential Nonlinearity(DNL)are better than±0.88 LSB and±0.67 LSB,respectively.Meanwhile,the overall power consumption of the chip is 35 mW at 1.8 V power supply.Combined with these characteristics,the designed chip is suitable for TOF-based ranging applications.
文摘A real-time non-uniform rational B-spline （NURBS） surface interpolator is proposed and 5-axis machining method with a flat-end cutter is discussed. With the Taylor expansion and the coordinate transformation, the algorithms of NURBS interpolation, cutter effective machining radius, cutter offsetting and.inverse kinematics are deduced and implemented, respectively. Different from the conventional free-form surface machining, the proposed interpolator can real-time generate the motion commands of computer numerical control （CNC） machines with CC feedrate, rather than that of CL. An example part surface is demonstrated and the results of simulation show that the proposed method can be applied in actual 5-axis surface machining.
