The new AUV driven by multi-vectored thrusters not only has unique kinematic characteristics during the actual cruise but also exists uncertain factors such as hydrodynamic coefficients perturbation and unknown interf...The new AUV driven by multi-vectored thrusters not only has unique kinematic characteristics during the actual cruise but also exists uncertain factors such as hydrodynamic coefficients perturbation and unknown interference of tail fluid, which bring difficult to the stability of the AUV＇s control system. In order to solve the nonlinear term and unmodeled dynamics existing in the new AUV＇s attitude control and the disturbances caused by the external marine environment, a second-order sliding mode controller with double-loop structure that considering the dynamic characteristics of the rudder actuators is designed, which improves the robustness of the system and avoids the control failure caused by the problem that the design theory of the sliding mode controller does not match with the actual application conditions. In order to avoid the loss of the sliding mode caused by the amplitude and rate constraints of the rudder actuator in the new AUV＇s attitude control, the dynamic boundary layer method is used to adjust the sliding boundary layer thickness so as to obtain the best anti-chattering effects. Then the impacts of system parameters, rudder actuator＇s constraints and boundary layer on the sliding mode controller are computed and analyzed to verify the effectiveness and robustness of the sliding mode controller based on dynamic boundary layer. The computational results show that the original divergent second-order sliding mode controller can still effectively implement the AUV＇s attitude control through dynamically adjusting the sliding boundary layer thickness. The dynamic boundary layer method ensures the stability of the system and does not exceed the amplitude constraint of the rudder actuator, which provides a theoretical guidance and technical support for the control system design of the new AUV in real complex sea conditions.展开更多
Recently, switched control systems have been attracting much attention m the control community because the problems are not only academically challenging for the inherent complexity, but also of practical importance d...Recently, switched control systems have been attracting much attention m the control community because the problems are not only academically challenging for the inherent complexity, but also of practical importance due to its wide ranges of applications in nature, engineering, and social sciences.展开更多
As guest editors, it is our great honor to bring this special issue of the Journal of Control Theory and Applications devoted to Recent Advances and New Directions in Switched Control Systems.
Complexity is one of the leading features of modem control systems. It is caused by the complex properties of controlled plants and the varied requirements in controller designs. In dealing with the control problems w...Complexity is one of the leading features of modem control systems. It is caused by the complex properties of controlled plants and the varied requirements in controller designs. In dealing with the control problems with complexity, in the past two decades, a lot of papers have been published that reported fruitful results on different theoretical backgrounds and with different methodologies, such as differential geometry-based design methods, hybrid system theory, switching control, neural network-based intelligent control, etc.展开更多
This paper reports a new simple four-dimensional（4 D） hyperjerk chaotic system. The proposed system has only one stable equilibrium point. Hence, its strange attractor belongs to the category of hidden attractors. T...This paper reports a new simple four-dimensional（4 D） hyperjerk chaotic system. The proposed system has only one stable equilibrium point. Hence, its strange attractor belongs to the category of hidden attractors. The proposed system exhibits various dynamical behaviors including chaotic, periodic, stable nature, and coexistence of various attractors. Numerous theoretical and numerical methods are used for the analyses of this system. The chaotic behavior of the new system is validated using circuit implementation. Further, the synchronization of the proposed systems is shown by designing an adaptive integrator backstepping controller. Numerical simulation validates the synchronization strategy.展开更多
The previous operation of the ZLS-Burris gravity meter using a PDA already provides a significant improvement of the operation of a metal spring gravity meter. But in the practical field work the observer usually wish...The previous operation of the ZLS-Burris gravity meter using a PDA already provides a significant improvement of the operation of a metal spring gravity meter. But in the practical field work the observer usually wishes more information about the measurement and the collected data. This situation sug- gested an improvement of the software and computer hardware. The goal was to develop a small useful PC tool that eliminates these deficits. However, it resulted in a very extensive application software, which was developed during 2011-2015. Along the way, some unwanted effects of the original control circuit were detected. Therefore as a last step a complete new control circuit for the feedback system was developed. This new circuit is fast and smooth and without resonance effects to the system. The algorithm parameters can be specifically adapted to the specific gravity meter. The software has a security system that ensures the user, depending on his level of knowledge, a limited access to the software options. Furthermore, a customer project management system is integrated. The observer, the gravity meters, the projects and maps can be assigned. Several ZLS Burris gravity meters can be managed. A large station data management is integrated. Every station has up to more than twenty parameters, such as the mandatory coordinates or supplementary pictures of the station. External storage and documentation of the measurements are possible with extra modules. In addition the maintenance of the gravity meter system is significantly improved. The motor control of the early ZLS Burris gravity meter is also improved. The complete rotation is displayed on the screen. Finally, two survey examples show the advantages of the software related to the accuracy and the time needed for a measurement.展开更多
Iron deficiency (ID), defined as an insufficient supply of iron to the cells of the body after iron reserves have been exhausted, is the most prevalent single nutritional deficiency, affecting over 2, 000 million peop...Iron deficiency (ID), defined as an insufficient supply of iron to the cells of the body after iron reserves have been exhausted, is the most prevalent single nutritional deficiency, affecting over 2, 000 million people, mostly in the developing world. Infants, small children, adolescents and pregnant and fertile-age women are most vulnerable. Only about 50 % of people with ID develop iron deficiency anemia (IDA), since this is a late manifes tation of chronic ID. Based on the average daily iron requirement and on the rate of iron reutilization from red cell hemoglobin destruction, it can be estimated that after iron stores have been depleted, it takes about 4 months of ID erythropoiesis for adult women to have a drop in hemoglobin concentration [Hb] of 10 g/l, if the iron intake is only 70 % of requirement. IDA can be defined by a [Hb] below an appropriate cut-off point for age,sex, physiological condition and altitude above sea level, or by a [Hb] increment of morethan 10 g/l to the administration of adequate doses of iron. More than 85 % of the nutritional anemias are IDA alone, or of iron combined with folate or other nutrient deficiencies [WHO/UNICEF/UNU, 1997; Yip, 1994].展开更多
Cotton bollworm(Helicoverpa armigera) is an important agricultural pest that causes severe yield loss to crops,particularly to cotton.Transgenic Bt crops have been successful in
About one year on,international arms control and disarmament appeared to be rebounding to become an issue of great international attention,paralleling the issues of financial crisis and climate change.International nu...About one year on,international arms control and disarmament appeared to be rebounding to become an issue of great international attention,paralleling the issues of financial crisis and climate change.International nuclear disarmament re-dawned with high profile readjustments by the United States in its nuclear arms control policy and tactics.The US and Russia signed a new agreement of bilateral nuclear disarmament.Multilateral nuclear arms control has also softened,and the nuclear security issue loomed large.The Conference on the Review of Nuclear Non-proliferation was held,the main illustration of the adjustment by the US to its arms control policy and tactics.On balance,however,the US arms control and disarmament policies remain largely rhetorical,as its two strategic objectives of nuclear weapon policy--nuclear deterrence and non-proliferation--has been kept intact,and even intensified.展开更多
基金supported by National Hi-tech Research and Development Program of China (863 Program,Grant No.2006AA09Z235)Hunan Provincial Innovation Foundation for Postgraduate of China (Grant No. CX2009B003)
文摘The new AUV driven by multi-vectored thrusters not only has unique kinematic characteristics during the actual cruise but also exists uncertain factors such as hydrodynamic coefficients perturbation and unknown interference of tail fluid, which bring difficult to the stability of the AUV＇s control system. In order to solve the nonlinear term and unmodeled dynamics existing in the new AUV＇s attitude control and the disturbances caused by the external marine environment, a second-order sliding mode controller with double-loop structure that considering the dynamic characteristics of the rudder actuators is designed, which improves the robustness of the system and avoids the control failure caused by the problem that the design theory of the sliding mode controller does not match with the actual application conditions. In order to avoid the loss of the sliding mode caused by the amplitude and rate constraints of the rudder actuator in the new AUV＇s attitude control, the dynamic boundary layer method is used to adjust the sliding boundary layer thickness so as to obtain the best anti-chattering effects. Then the impacts of system parameters, rudder actuator＇s constraints and boundary layer on the sliding mode controller are computed and analyzed to verify the effectiveness and robustness of the sliding mode controller based on dynamic boundary layer. The computational results show that the original divergent second-order sliding mode controller can still effectively implement the AUV＇s attitude control through dynamically adjusting the sliding boundary layer thickness. The dynamic boundary layer method ensures the stability of the system and does not exceed the amplitude constraint of the rudder actuator, which provides a theoretical guidance and technical support for the control system design of the new AUV in real complex sea conditions.
文摘Recently, switched control systems have been attracting much attention m the control community because the problems are not only academically challenging for the inherent complexity, but also of practical importance due to its wide ranges of applications in nature, engineering, and social sciences.
文摘As guest editors, it is our great honor to bring this special issue of the Journal of Control Theory and Applications devoted to Recent Advances and New Directions in Switched Control Systems.
文摘Complexity is one of the leading features of modem control systems. It is caused by the complex properties of controlled plants and the varied requirements in controller designs. In dealing with the control problems with complexity, in the past two decades, a lot of papers have been published that reported fruitful results on different theoretical backgrounds and with different methodologies, such as differential geometry-based design methods, hybrid system theory, switching control, neural network-based intelligent control, etc.
文摘This paper reports a new simple four-dimensional（4 D） hyperjerk chaotic system. The proposed system has only one stable equilibrium point. Hence, its strange attractor belongs to the category of hidden attractors. The proposed system exhibits various dynamical behaviors including chaotic, periodic, stable nature, and coexistence of various attractors. Numerous theoretical and numerical methods are used for the analyses of this system. The chaotic behavior of the new system is validated using circuit implementation. Further, the synchronization of the proposed systems is shown by designing an adaptive integrator backstepping controller. Numerical simulation validates the synchronization strategy.
文摘The previous operation of the ZLS-Burris gravity meter using a PDA already provides a significant improvement of the operation of a metal spring gravity meter. But in the practical field work the observer usually wishes more information about the measurement and the collected data. This situation sug- gested an improvement of the software and computer hardware. The goal was to develop a small useful PC tool that eliminates these deficits. However, it resulted in a very extensive application software, which was developed during 2011-2015. Along the way, some unwanted effects of the original control circuit were detected. Therefore as a last step a complete new control circuit for the feedback system was developed. This new circuit is fast and smooth and without resonance effects to the system. The algorithm parameters can be specifically adapted to the specific gravity meter. The software has a security system that ensures the user, depending on his level of knowledge, a limited access to the software options. Furthermore, a customer project management system is integrated. The observer, the gravity meters, the projects and maps can be assigned. Several ZLS Burris gravity meters can be managed. A large station data management is integrated. Every station has up to more than twenty parameters, such as the mandatory coordinates or supplementary pictures of the station. External storage and documentation of the measurements are possible with extra modules. In addition the maintenance of the gravity meter system is significantly improved. The motor control of the early ZLS Burris gravity meter is also improved. The complete rotation is displayed on the screen. Finally, two survey examples show the advantages of the software related to the accuracy and the time needed for a measurement.
文摘Iron deficiency (ID), defined as an insufficient supply of iron to the cells of the body after iron reserves have been exhausted, is the most prevalent single nutritional deficiency, affecting over 2, 000 million people, mostly in the developing world. Infants, small children, adolescents and pregnant and fertile-age women are most vulnerable. Only about 50 % of people with ID develop iron deficiency anemia (IDA), since this is a late manifes tation of chronic ID. Based on the average daily iron requirement and on the rate of iron reutilization from red cell hemoglobin destruction, it can be estimated that after iron stores have been depleted, it takes about 4 months of ID erythropoiesis for adult women to have a drop in hemoglobin concentration [Hb] of 10 g/l, if the iron intake is only 70 % of requirement. IDA can be defined by a [Hb] below an appropriate cut-off point for age,sex, physiological condition and altitude above sea level, or by a [Hb] increment of morethan 10 g/l to the administration of adequate doses of iron. More than 85 % of the nutritional anemias are IDA alone, or of iron combined with folate or other nutrient deficiencies [WHO/UNICEF/UNU, 1997; Yip, 1994].
文摘Cotton bollworm(Helicoverpa armigera) is an important agricultural pest that causes severe yield loss to crops,particularly to cotton.Transgenic Bt crops have been successful in
文摘About one year on,international arms control and disarmament appeared to be rebounding to become an issue of great international attention,paralleling the issues of financial crisis and climate change.International nuclear disarmament re-dawned with high profile readjustments by the United States in its nuclear arms control policy and tactics.The US and Russia signed a new agreement of bilateral nuclear disarmament.Multilateral nuclear arms control has also softened,and the nuclear security issue loomed large.The Conference on the Review of Nuclear Non-proliferation was held,the main illustration of the adjustment by the US to its arms control policy and tactics.On balance,however,the US arms control and disarmament policies remain largely rhetorical,as its two strategic objectives of nuclear weapon policy--nuclear deterrence and non-proliferation--has been kept intact,and even intensified.
