针对五轴石材切板机床的圆形锯片安装中心相对于机床控制点存在偏置以及锯片本身尺寸导致过切的问题,对切削点相对于控制点的空间位姿关系进行了分析,对加工图元为直线时的各种工况进行了详尽研究,提出了一种基于美国3S开放式系统(Servo...针对五轴石材切板机床的圆形锯片安装中心相对于机床控制点存在偏置以及锯片本身尺寸导致过切的问题,对切削点相对于控制点的空间位姿关系进行了分析,对加工图元为直线时的各种工况进行了详尽研究,提出了一种基于美国3S开放式系统(Servo Works S-140M)的偏置补偿算法,建立了刀位轨迹与数控轨迹之间的联系。通过系统仿真功能验证了该算法的正确性,并通过实际加工进行了测试。研究结果表明,所加工出的零件能满足加工工艺和精度要求,提高了加工效率和加工精度,降低了生产成本。展开更多
Few function about 3D tool radius compensation is applied to generating executable motion control commands in the existing computer numerical control (CNC) systems. Once the tool radius is changed, especially in the c...Few function about 3D tool radius compensation is applied to generating executable motion control commands in the existing computer numerical control (CNC) systems. Once the tool radius is changed, especially in the case of tool size changing with tool wear in machining, a new NC program has to be recreated. A generic 3D tool radius compensation method for multi-axis peripheral milling in CNC systems is presented. The offset path is calculated by offsetting the tool path along the direction of the offset vector with a given distance. The offset vector is perpendicular to both the tangent vector of the tool path and the orientation vector of the tool axis relative to the workpiece. The orientation vector equations of the tool axis relative to the workpiece are obtained through homogeneous coordinate transformation matrix and forward kinematics of generalized kinematics model of multi-axis machine tools. To avoid cutting into the corner formed by the two adjacent tool paths, the coordinates of offset path at the intersection point have been calculated according to the transition type that is determined by the angle between the two tool path tangent vectors at the corner. Through the verification by the solid cutting simulation software VERICUTwith different tool radiuses on a table-tilting type five-axis machine tool, and by the real machining experiment of machining a soup spoon on a five-axis machine tool with the developed CNC system, the effectiveness of the proposed 3D tool radius compensation method is confirmed. The proposed compensation method can be suitable for all kinds of threeto five-axis machine tools as a general form.展开更多
A double sampling circuit to eliminating fixed pattern noise(FPN) in CMOS image sensor (CIS) is presented. Double sampling is implemented by column switch capacitor amplifier directly, and offset compensation is added...A double sampling circuit to eliminating fixed pattern noise(FPN) in CMOS image sensor (CIS) is presented. Double sampling is implemented by column switch capacitor amplifier directly, and offset compensation is added to the amplifier to suppress column FPN. The amplifier is embedded in a 64×64 CIS and successfully fabricated with chartered 0.35 μm process. Theory analysis and circuit simulation indicate that FPN can be suppressed from millivolt to microvolt. Test results show that FPN is smaller than one least-significant bit of 8 bit ADC. FPN is reduced to an acceptable level with double sampling technique implemented with switch capacitor amplifier.展开更多
文摘针对五轴石材切板机床的圆形锯片安装中心相对于机床控制点存在偏置以及锯片本身尺寸导致过切的问题,对切削点相对于控制点的空间位姿关系进行了分析,对加工图元为直线时的各种工况进行了详尽研究,提出了一种基于美国3S开放式系统(Servo Works S-140M)的偏置补偿算法,建立了刀位轨迹与数控轨迹之间的联系。通过系统仿真功能验证了该算法的正确性,并通过实际加工进行了测试。研究结果表明,所加工出的零件能满足加工工艺和精度要求,提高了加工效率和加工精度,降低了生产成本。
基金supported by National Major S&T Program of China(Grant No. 2010zx04008-041)National Hi-tech Research and Development Program of China (863 Program, Grant No.2011AA04A104)
文摘Few function about 3D tool radius compensation is applied to generating executable motion control commands in the existing computer numerical control (CNC) systems. Once the tool radius is changed, especially in the case of tool size changing with tool wear in machining, a new NC program has to be recreated. A generic 3D tool radius compensation method for multi-axis peripheral milling in CNC systems is presented. The offset path is calculated by offsetting the tool path along the direction of the offset vector with a given distance. The offset vector is perpendicular to both the tangent vector of the tool path and the orientation vector of the tool axis relative to the workpiece. The orientation vector equations of the tool axis relative to the workpiece are obtained through homogeneous coordinate transformation matrix and forward kinematics of generalized kinematics model of multi-axis machine tools. To avoid cutting into the corner formed by the two adjacent tool paths, the coordinates of offset path at the intersection point have been calculated according to the transition type that is determined by the angle between the two tool path tangent vectors at the corner. Through the verification by the solid cutting simulation software VERICUTwith different tool radiuses on a table-tilting type five-axis machine tool, and by the real machining experiment of machining a soup spoon on a five-axis machine tool with the developed CNC system, the effectiveness of the proposed 3D tool radius compensation method is confirmed. The proposed compensation method can be suitable for all kinds of threeto five-axis machine tools as a general form.
基金Supported by National Natural Science Foundation of China (No.60576025).
文摘A double sampling circuit to eliminating fixed pattern noise(FPN) in CMOS image sensor (CIS) is presented. Double sampling is implemented by column switch capacitor amplifier directly, and offset compensation is added to the amplifier to suppress column FPN. The amplifier is embedded in a 64×64 CIS and successfully fabricated with chartered 0.35 μm process. Theory analysis and circuit simulation indicate that FPN can be suppressed from millivolt to microvolt. Test results show that FPN is smaller than one least-significant bit of 8 bit ADC. FPN is reduced to an acceptable level with double sampling technique implemented with switch capacitor amplifier.
