38 results about "Barrier lyapunov function" patented technology

The invention relates to a robot arm system preset performance control method based on a neural network. The robot arm system preset performance control method based on the neural network comprises the following steps of: S1, establishing a mathematical model of a robot arm servo system, and designing a tangential barrier Lyapunov function; S2, designing a preset performance adaptive controller bycombining the tangential barrier Lyapunov function with an inversion method; and S3, carrying out stability analysis. According to the robot arm system preset performance control method based on theneural network, by setting parameter values of a constraint boundary function, steady-state performance and transient-state performance of the system can be ensured. Moreover, the neural network is utilized to approach an uncertain part of the model and a derivative of a virtual control quantity, so that design of the controller is effectively simplified, robustness of the system is improved to acertain degree, and the robot arm servo system can implement accurate and rapid tracking control.

The invention discloses an unmanned surface vehicle distributed formation control method under collision avoidance and connection retention constraint. The method comprises the following steps: building a kinematic and dynamic model of an unmanned surface vehicle; describing information interaction among individuals in an unmanned surface vehicle formation system through an unoriented topologicalgraph; building a distance error equation, a relative course angle error equation and an azimuth angle error equation of neighboring unmanned surface vehicles on the k side, and describing the collision avoidance and connection retention constraint into a constraint problem of formation error; using a logarithmic barrier lyapunov function to guarantee that the formation error satisfies a constraint condition of preset transient state performance, and by a backstepping design method, performing design of a virtual controller for a relative course angle error system, a distance error system andan azimuth angle error system; by a dynamic surface control technology, avoiding a problem of repeated derivation to the virtual controller and solving a problem of failure in measurement of acceleration in design of a formation controller; and designing the distributed formation controller based on a disturbance observer.

The invention relates to a hypersonic aircraft robust control method considering attack angle asymmetric constraints. The hypersonic aircraft robust control method regards an attack angle as a systemstate by considering a height tracking situation, designs a control law on the basis of an asymmetric barrier Lyapunov function, introduces attack angle tracking error asymmetric constraint information into the control law, guarantees that errors are limited in a preset asymmetric interval, meanwhile, performing amplitude limiting on attack angle virtual control, combines the errors and the attackangle virtual control to achieve the attack angle asymmetric constraints, and guarantees the normal operation of a scramjet engine. Considering uncertainty of the system, a robust term is added to estimate an upper bound of an unknown nonlinear function in the design of a controller, and the influence caused by the uncertainty is compensated. The hypersonic aircraft robust control method designsthe PID controller for a speed subsystem to realize speed tracking.

The invention relates to a multi-leg cooperative control method for an underwater multi-leg robot system, belongs to the technical field of cooperative control of underwater multi-leg robots, and aimsto solve the problem that a communication delay exists among different mechanical legs due to the influence of a processor operation speed and a signal transmission path on a multi-leg robot. A barrier Lyapunov function in a logarithmic form is introduced, so that a trajectory tracking error of the system always meets a set error limit requirement; only a communication topology among the different mechanical legs is required to be a directed graph, and only part of followers can obtain information of a leader, so that the communication burden caused by global knowing of the information is avoided; and an input signal source is selected as a virtual leader, so that the change of the leader is more flexible, and the requirement of the robot on the motion flexibility is met. The method is suitable for cooperative motion control of the underwater multi-leg robot.

The invention discloses an unmanned surface vehicle tracking error constraint control method under a random disturbance, which designs a controller for an unmanned surface vehicle under the random disturbance, and ensures that the tracking errors are finally converged to a zero point. The method comprises the following steps of constructing a kinematics model and a kinetic model of the unmanned surface vehicle; considering the existence of external random disturbances in a marine dynamic environment, describing the kinetic model of the unmanned surface vehicle as a standard non-linear stochastic model form; using a tangent barrier Lyapunov function to ensure that the tracking errors meet the constraint condition, and using a backstepping method to design a virtual controller for a trackingerror system of the unmanned surface vehicle; and using an adaptive control technology to solve the problem of parameter uncertainty in the controller design. The unmanned surface vehicle tracking error constraint control method under the random disturbance provided by the invention can realize the accurate tracking of the trajectory under a random disturbance environment, the errors satisfy a preset boundary condition, and the control effect is good.

The invention discloses a rigid aircraft attitude constraint tracking control method based on an improved barrier Lyapunov function. Aiming at a rigid aircraft with an external disturbance and an uncertain rotational inertia, a novel improved barrier Lyapunov function suitable for constraint and non-constraint conditions is constructed, then a reverse-step control and a self-adaptive method are combined, the rigid aircraft attitude constraint tracking control method based on the improved barrier Lyapunov function is provided. The application of the improved barrier Lyapunov function realizes the constraint of aircraft output, and the overall uncertainty can be estimated under the condition that any priori knowledge is not needed through the self-adaptive method. According to the control method, under the condition that external interference and rotational inertia are not determined, and the consistency of an aircraft attitude tracking error and an angular velocity error is ensured to be finally bonded.

The invention relates to an output limited backstepping control method for a four-rotor aircraft based on a symmetrical time-invariant barrier Lyapunov function. Aimed at a dynamic system of the four-rotor aircraft, the symmetrical time-invariant barrier Lyapunov function is selected, and the output limited backstepping control method for the four-rotor aircraft based on the symmetrical time-invariant barrier Lyapunov function is designed to ensure that system output is limited within certain range, avoid excessive overshoot, and reduce arrival time, and further to improve the dynamic responseperformance of the four-rotor aircraft system. The method provided by the invention enables that the system has a better dynamic response process.

The invention discloses a state variable full-constraint direct yawing moment control algorithm based on a pavement adhesion coefficient, and the algorithm introduces the concept of a barrier Lyapunov function (BLF) into the design of a direct yawing moment controller. In the design process of the controller, safety constraint boundaries of two state variables of a side slip angle and a yaw velocity brought by a pavement adhesion coefficient are considered, and the side slip angle and the yaw velocity are constrained at the same time based on the pavement adhesion coefficient. Therefore, it is fundamentally guaranteed that the side slip angle and the yaw velocity do not violate constraint conditions in tracking control, the unstable working conditions of drifting, transverse drifting and the like caused by the too large side slip angle and the too large yaw velocity of the automobile under the limit working condition are fundamentally avoided, and the transverse stability of the automobile in the running process is improved. Meanwhile, the direct yawing moment full-state constraint controller has shorter tracking convergence time under the condition that constraint conditions are not violated, and the possibility of dangerous working conditions is reduced.

The invention discloses a limited state-based permanent magnet synchronous motor fuzzy position tracking control method. According to the method, the problems of non-linearity and iron loss existing in electric automobile motor driving and control systems are solved; the state quantity and the control quantity of the motor system are restrained on the basis of a Barrier Lyapunov function, meanwhile, and a fuzzy logic system is utilized to approach a nonlinear function in the system, and a fuzzy self-adaptive position tracking controller is constructed. According to the method disclosed by theinvention, the tracking error of the system can be ensured to be converged into a small enough neighborhood of the original point; and the simulation result shows that the state quantities of the motor are ensured to be in the constraint space of the system by virtue of the method of the invention, and the input of the controller is stable in a bounded region. According to the method, the rapid and effective response of the position tracking control of the permanent magnet synchronous motor of the electric vehicle is realized, and the method is more suitable for a control object requiring rapid dynamic response such as an electric automobile driving system.

The invention discloses a bounded output control method for a four-rotor aircraft. In order to solve the problem of excessive overshoot of an output value of a four-rotor aircraft during actual takeoff, the invention designs a bounded output control method based on a barrier Lyapunov function (BLF). The method not only can enable the actual output value of a four-rotor aircraft to track an expected output value, but also can enable the actual output value to be always kept in a preset safety range. According to the method, a BLF and sliding mode control are combined to design a controller, a traditional sliding mode surface is restrained within a certain range through the BLF, and therefore it is guaranteed that the output value of the four-rotor aircraft is kept within a certain range, itis finally proved that the control system is stable, and meanwhile it can be guaranteed that the actual output value is bounded.

The invention discloses a cascade control method for finite time path tracking of an autonomous underwater vehicle, and belongs to the technical field of underwater vehicle tracking control. The method comprises the following steps: building a kinetic equation and a kinematics equation of the autonomous underwater vehicle; establishing a path tracking error dynamic equation according to a kinematics equation of the autonomous underwater vehicle; designing a virtual guidance and kinematics equivalent controller, and converting the path tracking error dynamic equation into a novel cascade system; carrying out limited control over the speed and the course of the autonomous underwater vehicle through a speed error subsystem and a course error subsystem, stabilizing a cascade disturbance subsystem through a barrier Lyapunov function and a finite time control method, and then verifying sufficient conditions for global finite time stability of a cascade system, therefore, the global finite time stability of closed-loop signals is ensured.

The invention discloses a robust control method of an active suspension system based on time-varying displacement constraint and belongs to the field of automobile stability control technologies. According to the method, stress analysis is performed on a bodywork and tires under a suspension respectively according to the second law and the third law of Newton, a 1/4 automobile active suspension system mathematical model containing an actuator fault mathematical model is established, the nonlinear active suspension system is identified based on a radial basis function neural network, an actuator with a fault compensation function and a self-adaptive law of the actuator are designed, a barrier Lyapunov function is adopted to verify the stability of the closed-loop active suspension system, and finally parameters of the actuator and the self-adaptive law are adjusted to achieve the final control objective. Through the method, the thought of constraint control is considered in the design of the fault compensation actuator of the active suspension system, the performance of the actuator with a fault is obviously improved, and the safety of an automobile is guaranteed.

The invention discloses a trajectory tracking control method and device for an underwater swimming mechanical arm with energy optimization.The method comprises the following steps: joint constraint and executor configuration singular point avoidance are considered, a control target of an inverse kinematics controller is described as a multi-target optimization problem, and the multi-target optimization problem is converted into a constrained quadratic programming problem; a dynamic recurrent neural network is proposed to solve the quadratic programming problem, an inverse kinematics optimization controller is generated to serve as an outer ring controller, and the outer ring controller is used for generating a generalized coordinate expected trajectory; and aiming at a state constraint problem, a dynamic controller is designed in an inner ring based on a barrier Lyapunov function, a generalized coordinate expected trajectory is used as an input of the dynamic controller, a radial basis function neural network is used to estimate a total dynamic unknown item of the USM, and the dynamic unknown item is used as a disturbance compensation item to be added into the dynamic controller. The device comprises a processor and a memory. The problems of joint physical limit avoidance and energy optimization are solved.

The invention discloses a full-strapdown guidance and control integrated design method based on a three-order model. The method comprises the following steps: step 1, establishing a three-order guidance and control integrated design model; step 2, clearly considering a design task of a guidance and control integrated algorithm considering full strapdown seeker view field constraints; step 3, constructing an auxiliary system, designing a first-layer expected virtual control quantity eta d, and processing the first-layer expected virtual control quantity eta d through an approximate saturation function to obtain a first-layer virtual control quantity eta c; step 4, designing a second-layer virtual control quantity omega zc by utilizing a Barrier Lyapunov function; step 5, designing an actualrudder deflection angle instruction delta z; step 6, integrating the steps 3-5 to obtain the guidance and control integrated algorithm considering view field constraints; and step 7, checking the performance of the guidance and control integrated algorithm. The method can completely achieve a target, and guarantees that the full strapdown seeker view field constraints are satisfied.

The invention discloses a stability control method for a tethered combination under full-state constraint, and aims to solve the problem of quick and stable control of a system under full-state constraint, namely limited position and speed. Aiming at a plurality of uncertainty factors existing in the tethered combination system, designing an adaptive neural network scheme, and realizing rapid and accurate estimation of the total uncertainty of the system; secondly, respectively considering the generalized position and speed constraint of the system, and designing a barrier Lyapunov Function (BLF) to solve the problem of full-state constraint; then, designing a robust adaptive controller by adopting a backstepping method, and ensuring rapid, high-precision and stable control of the tethered combination system in the presence of state constraints and various uncertainties; and finally, carrying out Lyapunov stability proving on the designed controller. According to the invention, the position and speed of the assembly system can be ensured to be always within a constraint range, and the rapid, high-precision and stable control of the tethered assembly system under the existence of various uncertainties can be realized.

The invention relates to an unmanned airship formation flight control method and system. The method comprises the following steps: determining a barrier Lyapunov function containing a relative position limit value according to an expected formation; designing a virtual controller by using a backstepping method and the barrier Lyapunov function, and carrying out resolving to obtain an output quantity of the virtual controller; calculating an adaptive controller output quantity according to the output quantity of the virtual controller; designing a formation controller by using a backstepping method according to the output quantity of the self-adaptive controller; resolving the formation controller to obtain the output quantity of the formation controller; and controlling the rotating speed of a propeller of the unmanned airship according to the output quantity of the formation controller. According to the method and the system, for the networked underactuated unmanned airship with the formation flight trajectory tracking flight task requirement, the actuator delay problem and the relative position limitation requirement of the unmanned airship are considered, and high-precision and stable control over the formation flight of the unmanned airship is achieved.

The invention discloses a full-state constraint finite time control method for a permanent magnet synchronous motor based on instruction filtering. According to the method, for the control precision requirement of the permanent magnet synchronous motor and the nonlinear problem in a driving system, the finite time control technology is adopted to accelerate the convergence speed of the system and improve the anti-interference capability of the system, and it is guaranteed that the tracking error of the system is converged to a small enough neighborhood of an original point; the problem of calculation explosion of traditional backstepping control is solved by introducing an instruction filtering technology; meanwhile, a finite time error compensation mechanism is designed, the influence of filtering errors is reduced, and the control precision of the system is improved; a barrier Lyapunov function is constructed to ensure that state variables such as rotor angular velocity and stator current of a permanent magnet synchronous motor system are always in a given state interval, and unknown nonlinear terms in the system are processed by using a neural network adaptive technology. According to the invention, the fast and effective response to the position tracking control of the permanent magnet synchronous motor is realized, and the robustness is good.

The invention discloses a nitrate nitrogen concentration control method based on a time delay compensation strategy, and belongs to the field of control. Aiming at the problem that the nitrate nitrogen concentration is difficult to effectively control due to time-varying and time-lag in the denitrification process, a time-varying and time-lag model of the denitrification process is established through mechanism analysis and time-lag traceability, an unknown part in the model is identified by adopting a fuzzy neural network, and the nitrate nitrogen concentration can be effectively controlled. A Lyapunov-Crasovsky functional is utilized to compensate the influence of time lag on the control performance, and a barrier Lyapunov function is designed to ensure that the nitrate nitrogen concentration does not exceed a preset range. The result shows that the control method effectively eliminates the influence of time lag, ensures the specified tracking control performance, and improves the stability of the sewage treatment process.

The invention discloses a self-adaptation back stepping control method for a nanometer electro-mechanical system with output constraints and asymmetric dead zone input. The method comprises the following steps that mathematical description is performed on the nanometer electro-mechanical system, and the chaotic behavior of the nanometer electro-mechanical system is analyzed; a first error vector e1 of a controller is constructed, a tangent barrier Lyapunov function is constructed, and then virtual control input is obtained; a neural network is utilized for approaching characteristics of a nonlinear function with the arbitrarily small error, a second error vector e2 of the controller is calculated, a Lyapunov function is constructed, and a nanometer electro-mechanical system controller with the output constraints and asymmetric dead zone input is obtained to complete the self-adaptation back stepping control method. According to the method, chaotic oscillation and dead zone shivering of the nanometer electro-mechanical system are effectively constrained, and the precision and robustness of the system are improved on the premise that it is ensured that output does not violate constraints.