The DSC(direct self control) of speed regulation technology was applied to drive a motor running at a certain overloading ratio in intermittent working conditions.To control motor temperatures rising effectively,a fin...The DSC(direct self control) of speed regulation technology was applied to drive a motor running at a certain overloading ratio in intermittent working conditions.To control motor temperatures rising effectively,a finite element method with an iterative approach was applied to simulate real working conditions and analyze the temperature rising of the inner part of the motor.Application of DSC speed regulation realizes the invariable torque output quickly and avoids the peak current at the start state in favor of the motor temperature decreasing.Based on an analysis with the finite limit method,some effective measures were taken to improve the ability of the motor to expel heat.The overload ability of the motor was improved and the stable motor temperature rising was obtained,fulfilling the demands of electrical screw presses.展开更多
Fast response and stable torque output are crucial to the performance of electric screw presses. This paper describes the design of a direct torque control (DTC) system for speeding up torque response and reducing the...Fast response and stable torque output are crucial to the performance of electric screw presses. This paper describes the design of a direct torque control (DTC) system for speeding up torque response and reducing the starting current of electric screw presses and its application to the J58K series of numerical control electric screw presses with a dual-motor drive. The DTC drive system encompasses speed control, torque reference control, and switching frequency control. Comparison of the DTC dual-AC induction motor drive with corresponding AC servo motor drive showed that for the J58K-315 electric screw press, the DTC drive system attains a higher maximum speed (786 r/min) within a shorter time (1.13 s) during a 250 mm stroke and undergoes smaller rise in temperature (42.0 °C) in the motor after running for 2 h at a 12 min-1 strike frequency than the AC servo motor drive does (751 r/min within 1.19 s, and 50.6 °C rise). Moreover, the DTC AC induction motor drive, with no need for a tachometer or position encoder to feed back the speed or position of the motor shaft, enjoys increased reliability in a strong-shock work environment.展开更多
背景:关于单个皮质骨轨迹螺钉的生物力学研究国内外已有多篇文章报道,但关于椎体、融合器、钉棒整个运动单元的生物力学研究,特别是关于皮质骨轨迹螺钉联合传统椎弓根螺钉(cortical bone trajectory combined with pedicle screw,CBTPS...背景:关于单个皮质骨轨迹螺钉的生物力学研究国内外已有多篇文章报道,但关于椎体、融合器、钉棒整个运动单元的生物力学研究,特别是关于皮质骨轨迹螺钉联合传统椎弓根螺钉(cortical bone trajectory combined with pedicle screw,CBTPS)固定方式对运动单元的应力分布情况及内固定装置稳定性的相关研究报道并不多。目的:归纳分析传统椎弓根螺钉固定与CBTPS固定骨质疏松椎体运动单元上的生物力学差异。方法:基于一位骨质疏松志愿者(骨密度T值<-0.25 SD)的CT数据,建立L3到骶椎椎体功能单元骨质疏松有限元模型。通过有效性验证后,建立传统椎弓根螺钉和CBTPS两种固定模型,比较两种模型在前屈、后伸、左右侧屈、左右旋转6种工况下内固定的应力及椎体运动单元活动情况;比较两种内固定方式下运动单元的应力分布情况及内固定装置的稳定性。结果与结论:(1)有限元验证结果显示,模型可较好地模拟骨质疏松患者腰椎的生理活动。(2)两组模型在屈曲、后伸状态下,内固定装置最大应力接近,但是CBTPS组内固定装置在侧屈与旋转状态下钉棒系统最大应力值要大于传统椎弓根螺钉组,其中侧屈时,CBTPS组较传统椎弓根螺钉组增加了11.5%,在旋转时,CBTPS组较传统椎弓根螺钉组增加了25.2%。CBTPS组cage的应力均大于传统椎弓根螺钉组,其中侧屈时,CBTPS组较传统椎弓根螺钉组增加了17%,在旋转时,CBTPS组较传统椎弓根螺钉组增加了15%。(3)两组模型在静载、前屈、后伸、侧屈、旋转状态下,椎间活动度相当,两种内固定装置能提供相似的稳定性。(4)总得来说,两种固定方式均可加强腰椎融合节段的固定强度,提供类似的节段稳定性,但CBTPS内固定方式可进一步加强融合节段的力学强度,提供更好的融合应力环境。展开更多
基金the Natural Science Foundation of Hubei Province (No.2004AA101E04)
文摘The DSC(direct self control) of speed regulation technology was applied to drive a motor running at a certain overloading ratio in intermittent working conditions.To control motor temperatures rising effectively,a finite element method with an iterative approach was applied to simulate real working conditions and analyze the temperature rising of the inner part of the motor.Application of DSC speed regulation realizes the invariable torque output quickly and avoids the peak current at the start state in favor of the motor temperature decreasing.Based on an analysis with the finite limit method,some effective measures were taken to improve the ability of the motor to expel heat.The overload ability of the motor was improved and the stable motor temperature rising was obtained,fulfilling the demands of electrical screw presses.
基金Funded by the Natural Science Foundation of Hubei Province (No. 2004AA101E04)
文摘Fast response and stable torque output are crucial to the performance of electric screw presses. This paper describes the design of a direct torque control (DTC) system for speeding up torque response and reducing the starting current of electric screw presses and its application to the J58K series of numerical control electric screw presses with a dual-motor drive. The DTC drive system encompasses speed control, torque reference control, and switching frequency control. Comparison of the DTC dual-AC induction motor drive with corresponding AC servo motor drive showed that for the J58K-315 electric screw press, the DTC drive system attains a higher maximum speed (786 r/min) within a shorter time (1.13 s) during a 250 mm stroke and undergoes smaller rise in temperature (42.0 °C) in the motor after running for 2 h at a 12 min-1 strike frequency than the AC servo motor drive does (751 r/min within 1.19 s, and 50.6 °C rise). Moreover, the DTC AC induction motor drive, with no need for a tachometer or position encoder to feed back the speed or position of the motor shaft, enjoys increased reliability in a strong-shock work environment.
文摘背景:关于单个皮质骨轨迹螺钉的生物力学研究国内外已有多篇文章报道,但关于椎体、融合器、钉棒整个运动单元的生物力学研究,特别是关于皮质骨轨迹螺钉联合传统椎弓根螺钉(cortical bone trajectory combined with pedicle screw,CBTPS)固定方式对运动单元的应力分布情况及内固定装置稳定性的相关研究报道并不多。目的:归纳分析传统椎弓根螺钉固定与CBTPS固定骨质疏松椎体运动单元上的生物力学差异。方法:基于一位骨质疏松志愿者(骨密度T值<-0.25 SD)的CT数据,建立L3到骶椎椎体功能单元骨质疏松有限元模型。通过有效性验证后,建立传统椎弓根螺钉和CBTPS两种固定模型,比较两种模型在前屈、后伸、左右侧屈、左右旋转6种工况下内固定的应力及椎体运动单元活动情况;比较两种内固定方式下运动单元的应力分布情况及内固定装置的稳定性。结果与结论:(1)有限元验证结果显示,模型可较好地模拟骨质疏松患者腰椎的生理活动。(2)两组模型在屈曲、后伸状态下,内固定装置最大应力接近,但是CBTPS组内固定装置在侧屈与旋转状态下钉棒系统最大应力值要大于传统椎弓根螺钉组,其中侧屈时,CBTPS组较传统椎弓根螺钉组增加了11.5%,在旋转时,CBTPS组较传统椎弓根螺钉组增加了25.2%。CBTPS组cage的应力均大于传统椎弓根螺钉组,其中侧屈时,CBTPS组较传统椎弓根螺钉组增加了17%,在旋转时,CBTPS组较传统椎弓根螺钉组增加了15%。(3)两组模型在静载、前屈、后伸、侧屈、旋转状态下,椎间活动度相当,两种内固定装置能提供相似的稳定性。(4)总得来说,两种固定方式均可加强腰椎融合节段的固定强度,提供类似的节段稳定性,但CBTPS内固定方式可进一步加强融合节段的力学强度,提供更好的融合应力环境。
