An end-effector for a flexible drilling robot is designed, and a novel four-point algorithm of normal attitude regulation for this end-effector is presented. Four non-coplanar points can define a unique sphere tangent...An end-effector for a flexible drilling robot is designed, and a novel four-point algorithm of normal attitude regulation for this end-effector is presented. Four non-coplanar points can define a unique sphere tangent to them in spatial geometry, and the center point of the sphere and the radius can be calculated. The shape of a workpiece surface in the machining area is approximately regarded as such a sphere. A vector from the machining point to the center point is thus approximately regarded as a normal vector to the workpiece surface. By this principle, the algorithm first measures four coordinates on the curve in the drilling region using four sensors and calculates the normal vector at the drilling point, then calculates the error between the normal vector and the axis of the spindle. According to this error, the algorithm further figures out the angles of two revolving axes on the end- effector and the displacements of three linear axes on the robot main body, thus it implements the function of adjusting the spindle to be perpendicular to the curve at the drilling point. Simulation results of two kinds of curved surfaces show that accuracy and efficiency can be realized using the proposed algorithm.展开更多
Background： Cardiac pacing is a proven and effective treatment used worldwide with a low incidence of complications depending on the patient group. Late lead perforation is a rare complication without a standard trea...Background： Cardiac pacing is a proven and effective treatment used worldwide with a low incidence of complications depending on the patient group. Late lead perforation is a rare complication without a standard treatment. Case summary： We report a case of a 98-year old woman submitted to pacemaker implantation due to symptomatic second-degree atrio-ventricular block. After two days she returned to the hospital with thoracic pain and was diagnosed with RV （right ventricular） lead perforation. She was submitted to cardiac surgery with lead extraction and RV repair. Discussion： There are two major types of complications after pacemaker implantation, mechanical and infection. Reported perforation rates after pacemaker implantation range from 0.1%-0.8%. While acute lead perforation is very well described, late lead perforation is only described in case reports with a low rate of tamponade or death. Management of subacute or delayed RV lead perforation is not well defined due to very limited data. Question remains on whether to extract the lead or not.展开更多
Positioning of screw holes is an important production procedure for steel construction connecting with bolts. In this paper, a new production method is presented, in which the digital camera is used for taking picture...Positioning of screw holes is an important production procedure for steel construction connecting with bolts. In this paper, a new production method is presented, in which the digital camera is used for taking pictures of screw holes and other techniques are advanced. This paper also indicates that the pixels of CCD chip in photogrammetry should be chosen as all geometric units in an image, such as interior elements and all kinds of distortions. The measure can also simplify the camera calibration for determining the size of non-square pixel.展开更多
An equivalent corrugation pitch-modulated （ECPM） distributed feedback （DFB） semiconductor laser with two equivalently assisted phase shifts （EAPS） was theoretically studied and experimentally demonstrated. The s...An equivalent corrugation pitch-modulated （ECPM） distributed feedback （DFB） semiconductor laser with two equivalently assisted phase shifts （EAPS） was theoretically studied and experimentally demonstrated. The simulated results showed that the longitudinal photon density distribution of the ECPM ＋ EAPS DFB lasers was much more uniform than that of a sole ECPM DFB laser without EAPS, and the longitudinal spatial hole burning was therefore suppressed more effectively. The results of experiment showed that good single longitudinal mode operation was achieved, with side mode suppression ratio （SMSR） being over 35 dB, and the wavelength range was from 1,559.64 to 1,563.02 nm when the operation current was from 50 to 160 mA at the temperature of 25 ℃, and the SMSR increased to 46.29 dB when the injection current was 130 mA.展开更多
基金National Science and Technology Major Project(No.2009ZX04014-023)
文摘An end-effector for a flexible drilling robot is designed, and a novel four-point algorithm of normal attitude regulation for this end-effector is presented. Four non-coplanar points can define a unique sphere tangent to them in spatial geometry, and the center point of the sphere and the radius can be calculated. The shape of a workpiece surface in the machining area is approximately regarded as such a sphere. A vector from the machining point to the center point is thus approximately regarded as a normal vector to the workpiece surface. By this principle, the algorithm first measures four coordinates on the curve in the drilling region using four sensors and calculates the normal vector at the drilling point, then calculates the error between the normal vector and the axis of the spindle. According to this error, the algorithm further figures out the angles of two revolving axes on the end- effector and the displacements of three linear axes on the robot main body, thus it implements the function of adjusting the spindle to be perpendicular to the curve at the drilling point. Simulation results of two kinds of curved surfaces show that accuracy and efficiency can be realized using the proposed algorithm.
文摘Background： Cardiac pacing is a proven and effective treatment used worldwide with a low incidence of complications depending on the patient group. Late lead perforation is a rare complication without a standard treatment. Case summary： We report a case of a 98-year old woman submitted to pacemaker implantation due to symptomatic second-degree atrio-ventricular block. After two days she returned to the hospital with thoracic pain and was diagnosed with RV （right ventricular） lead perforation. She was submitted to cardiac surgery with lead extraction and RV repair. Discussion： There are two major types of complications after pacemaker implantation, mechanical and infection. Reported perforation rates after pacemaker implantation range from 0.1%-0.8%. While acute lead perforation is very well described, late lead perforation is only described in case reports with a low rate of tamponade or death. Management of subacute or delayed RV lead perforation is not well defined due to very limited data. Question remains on whether to extract the lead or not.
文摘Positioning of screw holes is an important production procedure for steel construction connecting with bolts. In this paper, a new production method is presented, in which the digital camera is used for taking pictures of screw holes and other techniques are advanced. This paper also indicates that the pixels of CCD chip in photogrammetry should be chosen as all geometric units in an image, such as interior elements and all kinds of distortions. The measure can also simplify the camera calibration for determining the size of non-square pixel.
基金supported by the National Natural Science Foundation of China(61306068 and 61435014)the Natural Science Foundation of Jiangsu Province of China(BK20130585 and BK20140414)+1 种基金the National High Technology Research and Development Program(SS2015AA012302)the Applied Basic Research Project of Suzhou City(SYG201309)
文摘An equivalent corrugation pitch-modulated （ECPM） distributed feedback （DFB） semiconductor laser with two equivalently assisted phase shifts （EAPS） was theoretically studied and experimentally demonstrated. The simulated results showed that the longitudinal photon density distribution of the ECPM ＋ EAPS DFB lasers was much more uniform than that of a sole ECPM DFB laser without EAPS, and the longitudinal spatial hole burning was therefore suppressed more effectively. The results of experiment showed that good single longitudinal mode operation was achieved, with side mode suppression ratio （SMSR） being over 35 dB, and the wavelength range was from 1,559.64 to 1,563.02 nm when the operation current was from 50 to 160 mA at the temperature of 25 ℃, and the SMSR increased to 46.29 dB when the injection current was 130 mA.
