31 results about "Affine nonlinear system" patented technology

The invention discloses a spacecraft attitude stability control method by using a biasing tether. The method comprises: a system dynamics model is established; a nonaffine non-linear system model is converted into an affine non-linear system model; speed information is used as a virtual control value and a controller is designed; the designed virtual control value is used a control instruction and a speed/angular speed controlled is designed; and an anti-saturation module is added into the controller and an influence caused by movement limitation of a tether connecting point can be suppressed. According to the invention, on the basis of movement of a biasing tether point, an attitude of a capture mechanism is controlled, thereby substantially reducing fuel consumption of the capture mechanism during the operation task process. In addition, the nonaffine non-linear system model is converted into the affine non-linear system model by means of first-order taylor expansion and that the similarity and error meet the Lipschitz condition is demonstrated; and when the system design is controlled, an adaptive compensation item compensation module error is designed. The method is simple and the practicability is high.

The invention provides a non-affine and nonlinear fault-tolerant controller design method for a non-affine and nonlinear system with disturbance and parameter uncertainty. The designed observer can be applied to the nonlinear system with non-affine parameters, and the observer has ideal robustness in the presence of the parameters of large-range variation. Fault information and disturbance information are hidden in the observer. A fault-tolerant controller is dynamically designed based on the observer. Due to the fact that the system is the non-affine and nonlinear system, the design of the controller is not easy. The invention provides the dynamic non-affine and nonlinear approximation method. The non-affine and nonlinear system is approximated into an affine nonlinear system with time-varying parameters. Parameters which need to be known are estimated online through a filter. A non-affine flight control system is used to verify the effectiveness of the provided method. The robust fault-tolerant control of the non-affine and nonlinear system can be realized.

The invention discloses a nonlinear self-healing control method for a multi-sensor fault of a hypersonic flight vehicle, and the method comprises the steps: obtaining a longitudinal affine nonlinear system of the hypersonic flight vehicle through employing an input and output feedback linearization technology for a longitudinal nonlinear model of a cruise stage of the hypersonic flight vehicle; establishing a sliding mode surface for the obtained system, and designing a sliding mode controller under a fault-free condition; and injecting a multi-sensor constant deviation fault into an originalhealth system, and designing a fault estimation scheme. Specifically, a nonlinear adaptive observer is designed for a speed channel; aiming at a height channel, a backstepping sliding mode observer isdesigned to estimate a state quantity and a sensor fault; and after a fault estimation result of the height sensor and the speed sensor is obtained, a fault-tolerant controller is designed to compensate output signals of the height sensor and the speed sensor. The method can solve the problem of fault-tolerant control under the condition that the longitudinal system of the hypersonic aircraft suffers from speed and angle channel multi-sensor faults, and the self-healing capacity of the system is improved.

The invention discloses a water turbine adjustment system based on random probability distribution control. Firstly, a water turbine speed adjustment system is directly modeled via a differential equation based on an affine nonlinear system, and thus a simplified dissipation Hamiltonian model of a water turbine system is built. Then, a control method based on probability distribution is designed by using a technology of acquiring an exact stationary solution of a dissipation non-integrable Hamiltonian system, and thus a preset stability probability density function value output by the water turbine system can be acquired. In addition, stability analysis of the system is to demonstrate that the transition probability density of a controlled system is convergent to the preset stability probability density function value by using a Lyapunov function method, and system simulation indicates that the provided control strategy can achieve an expected control effect.

The invention discloses an optimal control method of a single-machine infinite-bus affine nonlinear system. According to the optimal control method of the single-machine affine nonlinear system, based on a single-machine infinite-bus system, nonlinear optimal control design is performed; the equation of motion of the generator rotor of the single-machine infinite-bus system is written in the mode of an SISO (single input single output) affine nonlinear system; through coordinate mapping, a completely controllable and precisely linearized system can be obtained; then according to the design method of a quadric-form optimal control LQR (linear quadratic regulator), the controlled quantity of the precisely linearized system can be solved, accordingly a nonlinear optimal controller of the original system can be obtained, meanwhile, real-time online semi-physical simulation is performed to test the practical feasibility of a scheme. The optimal control method of the single-machine infinite-bus affine nonlinear system achieves precise linearization of the single-machine infinite-bus system and meanwhile takes the condition of non-real-time performance of pure digital offline simulation, thereby verifying the control effects of a controller based on theoretical control in actual real field application through semi-physical simulation experiments. By testing the effects of the designed controller during actual application, the optimal control method of the single-machine infinite-bus affine nonlinear system is beneficial to high truthfulness of the designed algorithms.

The invention discloses a voltage regulation method in a PMSM feedback linearization controller. The method comprises the steps of: establishing a state equation of a PMSM in a PMSM two-phase synchronous rotation dq coordinate system; performing affine of a mathematical model in a standard form of a nonlinear system for the state equation; adopting a feedback linearization method to perform linearization for the mathematical model in the standard form to obtain a feedback linearization mathematical model; and adopting the PI feedback regulation modulation ratio method, namely regulating the SVPWM modulation ratio through PI feedback to change the voltage of the motor to achieve PMSM voltage tracking and regulation. The method for controlling PMSM through adoption of input-output accurate feedback linearization and a method for regulating the modulation ratio through PI feedback are adopted to achieve PMSM voltage tracking and regulation, obtain the more accurate and stable speed effectof PMSM, achieve the PMSM global decoupling and the whole linear control and effectively improve the PMSM speed stability and the speed control accuracy.

The invention discloses a nonlinear ship course control model and a control system. The method comprises: based on fluid mechanics control equations including a continuity equation, a momentum equation and a state equation, and are combined with motion equations and state equations of ship course and rudder angle, establishing a high-order nonlinear mathematical model of a ship heading rudder angle by using a quadratic polynomial fitting method, then solving a proper switching surface and a stable sliding mode motion equation by using a sliding mode variable structure control theory, and taking the nonlinear mathematical model of the ship heading rudder angle as a class of affine nonlinear system, so as to obtain a stable switching surface; and solving a sliding mode variable structure controller structure of the nonlinear mathematical model of the ship course rudder angle so as to realize simultaneous control of two state variables of the ship course and the rudder angle. According to the method, the two state variables of the course angle and the rudder angle can be well controlled at the same time, response is fast, overshoot is small, and robustness is high.

The invention provides a data-based sewage treatment system self-learning trajectory tracking method, which realizes a self-learning optimal tracking control algorithm of a non-affine nonlinear systemby using a DHP structure, and is applied to sewage treatment process control in rainstorm weather. According to the method, a numerical method is adopted to solve stability control corresponding to an expected trajectory, and then a data-driven self-learning method for solving the optimal control law of the non-affine system based on iterative DHP is established. The method is applied to concentration control of dissolved oxygen and nitrate nitrogen so as to achieve a good trajectory tracking effect of a sewage treatment system.