针对比例-积分-微分(Proportional Integral Derivative,PID)控制系统,以恩平20-4组块动力定位(Dynamic Positioning,DP)浮托为依托,采用经验参数法与控制变量法相结合的方法,研究PID控制系统中比例参数K_(p)和微分参数K_(d)对浮托船定...针对比例-积分-微分(Proportional Integral Derivative,PID)控制系统,以恩平20-4组块动力定位(Dynamic Positioning,DP)浮托为依托,采用经验参数法与控制变量法相结合的方法,研究PID控制系统中比例参数K_(p)和微分参数K_(d)对浮托船定位精度(偏移半径)和推进器利用效率的影响。结果表明,随着K p的增大,推进器利用效率增加,甚至出现过盈的现象,偏移半径则是先减小后增大。采用控制变量法对K_(d)取值进行验证,表明随着K_(d)的增大,推进器利用效率增加,偏移半径反而有增大的趋势。研究为DP数值模拟中PID参数的选择提供依据。展开更多
In order to study the bending behavior of aluminum alloy 7050 thick plate during snake hot rolling, several coupled thermo-mechanical finite element(FE) models were established. Effects of different initial thicknesse...In order to study the bending behavior of aluminum alloy 7050 thick plate during snake hot rolling, several coupled thermo-mechanical finite element(FE) models were established. Effects of different initial thicknesses, pass reductions, speed ratios and offset distances on the bending value of the plate were analyzed. ‘Quasi smooth plate' and optimum offset distance were defined and quasi smooth plate could be acquired by adjusting offset distance, and then bending control equation was fitted. The results show that bending value of the plate as well as the extent of the increase grows with the increase of pass reduction and decrease of initial thickness; the bending value firstly increases and then keeps steady with the ascending speed ratio; the bending value can be reduced by enlarging the offset distance. The optimum offset distance varies for different rolling parameters and it is augmented with the increase of pass reduction and speed ratio and the decrease of initial thickness. A proper offset distance for different rolling parameters can be calculated by the bending control equation and this equation can be a guidance to acquire a quasi smooth plate. The FEM results agree well with experimental results.展开更多
Although chaotic signals are considered to have great potential applications in radar and communication engineering, their broadband spectrum makes it difficult to design an applicable amplifier or an attenuator for a...Although chaotic signals are considered to have great potential applications in radar and communication engineering, their broadband spectrum makes it difficult to design an applicable amplifier or an attenuator for amplitude conditioning. Moreover, the transformation between a unipolar signal and a bipolar signal is often required. In this paper, a more intelligent hardware implementation based on field programmable analog array （FPAA） is constructed for chaotic systems with complete amplitude control. Firstly, two chaotic systems with complete amplitude control are introduced, one of which has the property of offset boosting with total amplitude control, while the other has offset boosting and a parameter for partial control. Both cases can achieve complete amplitude control including amplitude rescaling and offset boosting. Secondly, linear synchronization is established based on the special structure of chaotic system. Finally, experimental circuits are constructed on an FPAA where the predicted amplitude control is realized through only two independent configurable analog module （CAM） gain values.展开更多
文摘针对比例-积分-微分(Proportional Integral Derivative,PID)控制系统,以恩平20-4组块动力定位(Dynamic Positioning,DP)浮托为依托,采用经验参数法与控制变量法相结合的方法,研究PID控制系统中比例参数K_(p)和微分参数K_(d)对浮托船定位精度(偏移半径)和推进器利用效率的影响。结果表明,随着K p的增大,推进器利用效率增加,甚至出现过盈的现象,偏移半径则是先减小后增大。采用控制变量法对K_(d)取值进行验证,表明随着K_(d)的增大,推进器利用效率增加,偏移半径反而有增大的趋势。研究为DP数值模拟中PID参数的选择提供依据。
基金Projects(2012CB619505,2010CB731703)supported by the National Basic Research Program of ChinaProject(CX2013B065)supported by Hunan Provincial Innovation Foundation for Postgraduate,China+1 种基金Project(51405520)supported by the National Natural Science Foundation of ChinaProject(zzyjkt2013-06B)supported by the State Key Laboratory of High Performance Complex Manufacturing(Central South University),China
文摘In order to study the bending behavior of aluminum alloy 7050 thick plate during snake hot rolling, several coupled thermo-mechanical finite element(FE) models were established. Effects of different initial thicknesses, pass reductions, speed ratios and offset distances on the bending value of the plate were analyzed. ‘Quasi smooth plate' and optimum offset distance were defined and quasi smooth plate could be acquired by adjusting offset distance, and then bending control equation was fitted. The results show that bending value of the plate as well as the extent of the increase grows with the increase of pass reduction and decrease of initial thickness; the bending value firstly increases and then keeps steady with the ascending speed ratio; the bending value can be reduced by enlarging the offset distance. The optimum offset distance varies for different rolling parameters and it is augmented with the increase of pass reduction and speed ratio and the decrease of initial thickness. A proper offset distance for different rolling parameters can be calculated by the bending control equation and this equation can be a guidance to acquire a quasi smooth plate. The FEM results agree well with experimental results.
基金Project supported by the Startup Foundation for Introducing Talent of Nanjing University of Information Science&Technology,China(Grant No.2016205)the Natural Science Foundation of the Jiangsu Higher Education Institutions of Jiangsu Province,China(Grant No.16KJB120004)+1 种基金the Priority Academic Program Development of Jiangsu Higher Education Institutionsthe Natural Science Foundation of Hebei Province,China(Grant No.A2015108010)
文摘Although chaotic signals are considered to have great potential applications in radar and communication engineering, their broadband spectrum makes it difficult to design an applicable amplifier or an attenuator for amplitude conditioning. Moreover, the transformation between a unipolar signal and a bipolar signal is often required. In this paper, a more intelligent hardware implementation based on field programmable analog array （FPAA） is constructed for chaotic systems with complete amplitude control. Firstly, two chaotic systems with complete amplitude control are introduced, one of which has the property of offset boosting with total amplitude control, while the other has offset boosting and a parameter for partial control. Both cases can achieve complete amplitude control including amplitude rescaling and offset boosting. Secondly, linear synchronization is established based on the special structure of chaotic system. Finally, experimental circuits are constructed on an FPAA where the predicted amplitude control is realized through only two independent configurable analog module （CAM） gain values.
