This article focuses on the bandwidth expansion of MEMS gyroscope for force-to-rebalance (FTR) rate measurement in both nondegenerate and degenerate cases. First, the composition of the MEMS gyroscope system is introd...
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This article focuses on the bandwidth expansion of MEMS gyroscope for force-to-rebalance (FTR) rate measurement in both nondegenerate and degenerate cases. First, the composition of the MEMS gyroscope system is introduced, and the transferfunctions of the operational modes are analyzed. Second, equivalent transformation and simplification of the FTR control loop without feedthrough were performed to obtain the sense modal transferfunctions for the nondegenerate and degenerate cases. Third, a unit negative feedback loop characterizing the frequency characteristics of the FTR control loop is formed based on the above transferfunction, and impact factors of bandwidth are analyzed by its open-loop transfer function. Based on the above open-loop transfer function and its cutoff frequency, gain margin, and phase margin, judging criteria, and design approaches for bandwidth expansion and its elements are proposed. The bandwidth expansion element is connected in series with the FTR rate control loop to increase the cutoff frequency and ensure reasonable phase and gain margins, thus accomplishing the bandwidth expansion of the phase-lead compensated FTR rate measurement. A method for obtaining the channel gain of the FTR rate control loop is finally presented. This allows for comparisons to be made without and with bandwidth expansion for the nondegenerate and degenerate cases, respectively. The results demonstrate that bandwidth expansion cannot be achieved through the sole adjustment of proportional-integrating controller parameters. Instead, the bandwidth expansion can be accomplished by incorporating additional components by the proposed judging criteria and design approaches.
Various methods of stability analysis of an airplane with a MIMO control system are considered in the framework of frequency analysis. They assume that the control system is open for selected signal with other loops c...
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Various methods of stability analysis of an airplane with a MIMO control system are considered in the framework of frequency analysis. They assume that the control system is open for selected signal with other loops closed or that system is open for all signals of selected loops and allow solving the stability equation and calculating the eigenvalues of the matrix of transferfunctions. It is shown that all methods deal with different forms of the same equation, and thus the equivalence of methods considered for calculating closed-loop stability domains is proved. The application of methods is demonstrated for calculation of stability domains for an airplane equipped with MIMO stability and control augmentation system in lateral motion that uses ailerons and rudder as control surfaces. It is shown that in the case of a MIMO system, an open-loop transfer function that defines closed-loop stability is a nonlinear function of control system gains;this introduces uncertainty to the concept of amplitude and phase margins.
This study develops a robust method to control the humanoid joint based on a disturbance observer (DOB). In controlling the bipedal robot, it is usually difficult to precisely compensate for the gravity torques, frict...
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This study develops a robust method to control the humanoid joint based on a disturbance observer (DOB). In controlling the bipedal robot, it is usually difficult to precisely compensate for the gravity torques, friction forces, model mismatch and so on. The authors regard these as disturbances and employ the DOB to design a robust controller for the humanoid joint. The requirements for joint control are firstly discussed;a single joint model, that is, inverted pendulum model, is illustrated and the open-loop transfer function of the ankle joint is also presented. The authors consider the DOB for compensation, develop the design criterions of the filter and propose the robust servocontrol structure of the joint controller. For a given simulated robot, the performance and robustness of the proposed controller are demonstrated comparing with the proportional-integral-differential controller, and the effect of model perturbations is especially considered in case of the system performance. The results show the validation and feasibility of the proposed method.
An extension of previous results concerning the effect of integrators on the closed-loop response overshoot is presented. It is shown that if the open-loop transfer function contains more integrators (i.e. [1/s]) than...
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An extension of previous results concerning the effect of integrators on the closed-loop response overshoot is presented. It is shown that if the open-loop transfer function contains more integrators (i.e. [1/s]) than the Laplace transform of the reference signal, then the resulting output response must exhibit overshoot, assuming that a one degree-of-freedom control configuration is used. Several corollaries are also derived. The obtained results are applicable to minimum and non-minimum phase linear systems, and also strictly proper and non-strictly proper linear systems. A non-overshooting output tracking controller is then proposed for linear chain of integrators, whose structure and performance are analysed.
The baroreflex system is the fastest mechanism in the body to regulate arterial pressure. Because the neural system (i.e., autonomic nervous system) mediates the baroreflex and the system operates under the closed-loo...
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ISBN:
(纸本)9781424441242
The baroreflex system is the fastest mechanism in the body to regulate arterial pressure. Because the neural system (i.e., autonomic nervous system) mediates the baroreflex and the system operates under the closed-loop condition, the quantitative dynamic characteristics of the baroreflex system remained unknown until recently despite the fact that a countless number of observational and qualitative studies had been conducted. In order to develop the artificial baroreflex system, i.e., the bionic baroreflex system, we first anatomically isolated the carotid sinuses to open the baroreflex loop and identified the open-loop transfer function of the baroreflex system using white noise pressure perturbations. We found that the baroreflex system is basically a lowpass filter and remarkably linear. As an actuator to implement the bionic baroreflex system, we then stimulated the sympathetic efferent nerves at various parts of the baroreflex loop and identified the transferfunctions from the stimulation sites to systemic arterial pressure. We found that the actuator responses can be described remarkably well with linear transferfunctions. Since transferfunctions of the native baroreflex and of the actuator were identified, the controller that is required to reproduce the native baroreflex transferfunction can be easily derived from those transferfunctions. To examine the performance of bionic baroreflex system, we implemented it animal models of baroreflex failure. The bionic baroreflex system restored normal arterial pressure regulation against orthostatic stresses that is indistinguishable from the native baroreflex system.
Supercapacitor assisted low-dropout (SCALDO) regulator technique is gradually expanding as a novel approach to design high-efficiency, low-frequency DC-DC converters where the load sees a high-quality output of a line...
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ISBN:
(纸本)9781509049745
Supercapacitor assisted low-dropout (SCALDO) regulator technique is gradually expanding as a novel approach to design high-efficiency, low-frequency DC-DC converters where the load sees a high-quality output of a linear regulator. Theoretical concepts, prototypes, and experimental validations of this patented technique have been well established and published in the past eight years. Further developing the SCALDO regulator's theoretical basis, the pole-zero analysis is presented in this paper. A basic background about the control loop, the open-loop transfer function, the poles and zeros of a PMOS LDO regulator are discussed here. The small-signal model of the overall SCALDO regulator is constructed using the supercapacitor circulation network and a discrete PMOS LDO regulator. With related to the small-signal model, the control loop, and the open-loop transfer function of the SCALDO regulator are derived. The results of the SCALDO regulator in terms of the DC gain, poles and zeros are compared with the PMOS LDO regulator. The theoretical analysis is validated using the simulated results obtained from the control system toolbox in MATLAB Simulink environment.
This paper is focused on adaptively controlling a linear infinite-dimensional system to cause it to regulate the output to zero in the presence of persistent disturbances. The plant (A, B, C) is described by a closed,...
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ISBN:
(纸本)9783952426937
This paper is focused on adaptively controlling a linear infinite-dimensional system to cause it to regulate the output to zero in the presence of persistent disturbances. The plant (A, B, C) is described by a closed, densely defined linear operator A that generates a continuous semigroup of bounded operators on a Hilbert space of states;the input-output operators B & C are finite rank linear operators. We show that there exists a direct model reference adaptive control law that regulates the output in the presence of disturbances of known waveform but unknown amplitude and phase. The conditions needed for the success of the direct adaptive controller include the need for (A, B, C) to be almost strictly dissipative (ASD). In finite dimensional space, ASD is equivalent to two simple open-loop requirements: the high frequency gain CB is sign-definite and the open-loop transfer function P(s) is minimum phase. Our main result will prove infinite-dimensional versions of these conditions for a large class of infinite-dimensional systems.
The design principle based on the minimum guaranteed phase margin developed by the authors in (Preitl and Precup, 1996, 1997a) is specific to control systems with variable parameters using controllers with dynamics (o...
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The design principle based on the minimum guaranteed phase margin developed by the authors in (Preitl and Precup, 1996, 1997a) is specific to control systems with variable parameters using controllers with dynamics (of PI or PID type). The quasi-PI fuzzy controller (briefly, PI-FC) can be considered in the design phase as a nonlinear controller but linearizable in the vicinity of operating points belonging to the control surface. In terms of such an assumption the paper proposes a method for the development of a PI-FC based on ensuring the variation of phase margin within a guaranteed desired interval. Due to the fact that PI-FC parameters are variable with respect to the operating point a condition for the robust stability of control systems developed by means of the method is derived. The efficiency of the method is exemplified for the speed control of a DC motor.
The authors have already proposed a new method for the algorithmic design of the controller as part of an automatic control system (briefly, ACS). The method has the specific feature in ensuring the maximum phase rese...
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The authors have already proposed a new method for the algorithmic design of the controller as part of an automatic control system (briefly, ACS). The method has the specific feature in ensuring the maximum phase reserve in the linear case, and it is immediately applicable to the field of electrical driving systems. The types of conventional controller (regulator, R) transferfunctions (t.f.s) (H(s)) result as function of the types of controlled plant (CP) transferfunctions (H(s)); only the cases of PI and PID controllers are taken into consideration in the paper. Several predictive and adaptive fuzzy controllers (FCs) are developed on the basis of the conventional PI and PID controllers; the design of these FCs is also presented. The proposed FCs ensure ACS performance enhancement that is pointed out by digital simulation for a case study; a comparative study of digital simulation results for ACSs with different types of controllers (conventional and fuzzy) is part of the paper. The FC is designed beginning from the linear controller (of PI or PID type) for the maximum phase reserve because the FC can be approximated as a linear element, and its parameters depend on the operating point. So, the term ”maximum phase reserve” from the title referring only to linear systems is justified.
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