190 results about "Feedback linearization" patented technology

Controls for an optical scanner, such as a single fiber scanning endoscope (SFSE) that includes a resonating optical fiber and a single photodetector to produce large field of view, high-resolution images. A nonlinear control scheme with feedback linearization is employed in one type of control to accurately produce a desired scan. Open loop and closed loops controllers are applied to the nonlinear optical scanner of the SFSE. A closed loop control (no model) uses either phase locked loop and PID controllers, or a dual-phase lock-in amplifier and two PIDs for each axis controlled. Other forms of the control that employ a model use a frequency space tracking control, an error space tracking control, feedback linearizing controls, an adaptive control, and a sliding mode control.

The invention relates to a self-adaptive index time varying slip form posture control method of a reentry flight vehicle, belonging to the technical field of flight vehicles. The method comprises the steps of firstly establishing a posture motion equation in a mode that a powerless reentry flight vehicle model is used as an object; secondly modifying the equation into the mode of an MIMO (Multiple Input Multiple Output) affine non-linear system, further applying a feedback linearization principle to carry out linearization processing so as to obtain a three-channel linearization model of pitching, rolling and yawing; aiming at the obtained linearization system, designing a modified self-adaptive index time varying slip form controller; and subsequently obtaining a control moment instruction for the posture control of the reentry flight vehicle, and inputting the control moment instruction into the reentry flight vehicle so as to control the posture. By combining the index time varying slip form control with a self-adaptive method, the problem of excessive adaptation of switch gain in the self-adaptive slip form control is solved to a certain extent, the uncertainty of system parameters and the influence of external disturbance can be suppressed effectively, and the precise posture control is realized.

A new feedback linearization approach to advanced control of single-unit and multi-unit HVAC systems is described. In accordance with the approach of the invention, this new nonlinear control includes a model-based feedback linearization part to compensate for the nonlinearity in the system dynamics. Therefore, the evaporating temperature and superheat values can be controlled by linear PI control designs to achieve desired system performance and reliability. The main advantages of the new nonlinear control approach include (1) better performance even with large model errors, (2) being able to adapt to indoor unit turn on/off operation, (3) much smaller PI control gains compared to that of current feedback PI controls, (4) much easier design procedures since there is no need for tuning the PI control gains over wide range operation.

The invention discloses a multi-terminal VSC-HVDC grid-connected transmission system controlling method applied to a large wind power plant. Wind power plant side convertor station outer ring power conducts inner ring current PI control, a grid field side convertor station outer ring direct voltage conducts inner ring current feedback linearization decoupling control, and therefore response characteristics and dynamic performance of a controller are improved. When operation of the wind power plant fluctuates greatly and a system loses capacity for adjusting the direct voltage, multi-terminal direct voltage control of direct voltage deviation is led into other convertor stations of the wind power plant for replacing a grid side convertor station to execute a voltage regulating task, therefore, power balance is maintained, normal operation of the system is ensured, and the effect that the system operates stably at a new operating point is also ensured.

The invention discloses a vehicle queue stability control method considering communication delay. The method comprises the steps that 1, a vehicle queue following mathematical model is established; 2,a nonlinear lower layer control gain is constructed by a feedback linearization strategy, and a node power unit is described as a node linear model; 3, a high-dimensional closed-loop state equation of a vehicle queue following control system under dynamic parameter uncertainty is established; 4, sufficient conditions are used for giving sufficient conditions that a vehicle queue with communication delay has a stabilization controller under the symmetric communication topology; and 5, the stabilization controller is constructed to obtain a controller gain so as to control static feedback control of a distributed controller, and the stability of the vehicle queue following control system is ensured. The method can ensure the stability of the vehicle queue following control system, reduces the vehicle queue following interval, increases the traffic flow, and reduces the energy consumption.

The invention discloses a method for controlling postures of an aircraft converged at a fixed time, relates to an aircraft posture control method, and belongs to the technical field of aircraft control. The method comprises the following steps of (1) establishing a reentry aircraft dynamic model and offering a limited time posture tracking task; (2) performing feedback linearization treatment on a model established in the step (1); and (3) giving out a limited time control law, starting the state of a system from an optional initial value and consulting a trace on tracking within a set time. The method can be used for implementing system error fixed time convergence when part of initial value information is unknown. Moreover, the method has high robustness under the conditions that system parameters are uncertain and external interferences exist.

A system and method for controlling an internal combustion engine provide valve actuation that selectively couples an energy storage device to a launching coil to recover energy stored in the magnetic field and valve spring of the launching coil, decouples the energy storage device during a valve opening or closing event to control energy supplied to the catching coil, and couples the energy storage device to the catching coil to transfer energy from the storage device to the catching coil to provide a repeatable soft landing. A nonlinear feedback controller incorporates a feedforward system with an observer to control the rate of energy into the magnetic field of the catching coil while compensating for system losses and work to overcome gas forces within the combustion chamber. Feedback linearization techniques improve stability of the control system.

The invention provides a method for achieving tooth space compensation for a flexible joint of a space manipulator. The method comprises the following steps that the position command signals yd of a direct current motor and the position signals y output by a kinetic model, with space influences taken into consideration, of the flexible joint of the space manipulator are collected, a sliding mode variable structure controller is designed, and a sliding-mode control law is obtained; the control input of a control system of the flexible joint after linear decoupling processing is carried out is obtained by adopting a differential geometry feedback linearization method according to the sliding-mode control law; according to the control input of the control system of the flexible joint after linear decoupling processing is carried out, a disturbance observer is designed for the kinetic model, with the space influences taken into consideration, of the flexible joint of the space manipulator, the control input, under compensation space nonlinear influences, of the flexible joint, and therefore it is guaranteed that the position output of the control system tracks the expected position signals with needed precision. According to the technical scheme of the method for achieving the tooth space compensation for the flexible joint of the space manipulator, influences of the space on the system position precision can be compensated for effectively, high-precision tracking control can be achieved, and the happening frequency of the buffeting phenomenon is reduced at the same time.

An apparatus comprising an amplifier comprising at least one amplifier transistor, a threshold detection network and a bypass capacitor. The amplifier may be configured to generate an output signal at a collector in response to an input signal received at a base. The threshold detection network may be coupled between the collector and the base of the amplifier transistor. The threshold detection network may include a bias transistor having a collector coupled to the collector of the amplifier transistor and an emitter coupled to the base of the amplifier transistor. The threshold detection circuit may be configured to (i) sense a feedback current and (ii) provide a DC signal to the base of the amplifier transistor for dynamically sourcing bias current to the amplifier. The bypass capacitor may be coupled to the base of the bias transistor.

The invention discloses a bidirectional direct-current converter feedback linearized back-stepping sliding-mode control mode. The bidirectional direct-current converter feedback linearized back-stepping sliding-mode control method comprises steps of using a filtering capacitance voltage and inductive current as control variables to establish a mathematic model of a bidirectional direct-current converter, performing feedback linearization on an original state variable to form a new linearized state equation, tracking an error with a new state variable as an input of a controller, combining a back-stepping method with a sliding-mode variable structure and designing a feedback control rule of a converter system, wherein the feedback control rule of the inverter system is performed on pulse width modulation and controls the bidirectional direct-current converter. The bidirectional direct-current converter feedback linearized back-stepping sliding-mode control mode combines the feedback linearization with the back-stepping sliding mode control to apply to the bidirectional direct-current converter, solves a non-minimum phase characteristic and a variable structure characteristic of the converter, greatly reduces fluctuation of bus voltage, expands a stable area of a system and has a good engineering application prospect.

The invention discloses a path following method and apparatus of an auxiliary parking system. The method comprises transverse control and longitudinal control. According to the transverse control, following error linear information is obtained through time scale zooming and feedback linearization, and based on this, transverse linear secondary optimal control is performed on the system; and the longitudinal control comprises planning a speed whose accelerated speed changes continuously along with a driving distance. The path following apparatus of the intelligent auxiliary parking system comprises an input unit, a path following unit and a vehicle control unit, wherein the path following unit comprises a transverse control sub-module and a longitudinal control sub-module, the transverse control sub-module, according to information input by the input unit, introduces an -alpha stability design based improved secondary performance index, designs an improved linear secondary optimal controller for performing closed-loop control on the system, and the longitudinal control sub-module designs a reasonable speed plan by use of an algorithm in which the accelerated speed changes continuously along with the driving distance. According to the invention, high precision, fast error convergence and passenger comfortableness in a parking process are guaranteed.

Through designing a radial basis function neural network compensator to estimate coupling between channels, a model uncertainty part and external interference, a pole-placement method is used to determine a gain initial value of a fractional order proportional differential controller, the control performance is further improved by the fine adjustment of a fractional order differential order number, the flexibility of a system is enhanced, finally a feedback linearization controller is designed to obtain a control amount, and the stable attitude control with strong anti-interference for a four-rotor unmanned aerial vehicle is realized. The invention has the advantages that an unmodeled part of the system, the coupling effect between the channels and the external interference are considered, and the universality of an attitude control method is improved. Through designing a radial basis function neural network estimator to estimate the unmodeled part of the system, the coupling effect between the channels and the external interference for compensation, the system has good anti-interference ability. On the basis of traditional proportional differential control, fractional order differential is introduced to improve the control performance and flexibility of the system.

The invention provides a large-size wind turbine feedback linearization power control method based on a radial basis function (RBF) neural network, and relates to the field of wind turbine power control. The control method comprises the steps that 1, on the basis that a wind turbine state space is built, an affine nonlinear model of a variation paddle controller is put forward, and the feedback linearization control law is designed; 2, an affine nonlinear model of a torque controller is built, and the feedback control law is designed; 3, on the basis of analyzing blade force vibration and tower vibration, the threshold value definition of a dual-loop controller is put forward for serving as the basis of controller transformation; and 4, the RBF neural network is designed to serve as a compensation control method for controlling errors. According to the dual-loop controller based on feedback linearization provided by the invention, the constant power control problems that the wind speed change is large, small, and fast after the rated wind speed is exceeded can be solved, the control precision is also improved through error compensation, and the robust performance of the system is improved.

The invention discloses a self-adaptive fuzzy control method for an active power filter based on feedback linearization, relates to the technical field of an active power filter, and respectively designs independent self-adaptive controllers aiming at a current loop and a voltage loop. As the current loop adopts the self-adaptive fuzzy controller for the active power filter based on the feedback linearization, the feedback linearization theory, fuzzy control, sliding mode control, self-adaptive control and Lyapunov stability theory are comprehensively utilized, and on the basis of ensuring the global stability, the purpose of harmonic compensation is realized. As the voltage loop adopts the self-adaptive fuzzy PI (process integration) control, according to the fuzzy rule, the control strategy can automatically adjust the PI parameter, strengthen the robustness of the system, improve the dynamic performance of the system, and ensure the tracing to the command voltage.

The invention relates to a method for removing chattering of sliding mode control of a permanent magnet synchronous motor, which can realize the removal of the chattering phenomenon of the sliding mode control of the permanent magnet synchronous motor. The method has the technical characteristics that: 1, a nonlinear mathematical model of the permanent magnet synchronous motor is established; 2, the nonlinear mathematical model is subjected to decoupling by adopting feedback linearization theory of a nonlinear system; and 3, a corresponding high-order sliding mode controller is designed on the basis of decoupling control respectively. By adopting a high-order sliding mode control algorithm with a differentiator, although indeterminate parameters, external interference, and other factors are present in the system, a robust controller aiming at a multi-input multi-output nonlinear permanent magnet synchronous motor is designed. The controller has the advantages of removing the chattering of the traditional sliding modes, having control accuracy and strong robustness of the traditional sliding modes, and making the control rules not limited by the degree of correlation of the system.

The invention provides a three-axis active posture control method for a space tether-robot. The method includes the steps that according to the orbit dynamics characteristic of the space tether-robot, the nominal tension required by a space tether of the space tether-robot in the equilibrium state is calculated; according to posture kinematics and dynamical equations of the space tether-robot, a control moment variable is determined, a state equation and an output equation of posture kinematics of the space tether-robot are established, and posture control moments in three directions are calculated according to a feedback linearization control law; according to the relation among the control moments, the space tether connecting point positions and the rotating speed of a reaction wheel, the corresponding space tether connecting point positions and the rotating angular speed of the reaction wheel are obtained. By the adoption of the method, according to the posture of a target and with the use of the space tether and the reaction wheel, three-axis posture coordinated control is conducted on the posture of the space tether-robot, and the method is suitable for three-axis posture control of the space tether-robot when the space tether-robot is located on a connecting line of a space platform and the geocenter.

The invention discloses an anti-communication-delay intelligent electric vehicle formation self-adaptive robust control method and belongs to the field of the intelligent safety and automatic drivingof vehicles. A wireless communication system and a vehicle-mounted sensor are used for collecting the driving state information of a vehicle and the information of other vehicles surrounding the vehicle; a feedback linearization technology is adopted to establish an intelligent electric vehicle formation longitudinal control model with parameter uncertainty characteristics; and therefore, the intelligent electric vehicle formation self-adaptive robust H-infinity control method capable of resisting communication delay is designed. With the method adopted, the problems of the parameter uncertainty of an intelligent electric vehicle formation dynamics system and the influence of external wireless communication delay can be solved, and the comprehensive performance of an intelligent electric vehicle formation control system is improved.

The invention discloses a method for realizing a feedback linearization double hysteresis composite controller of an active power filter, and the method comprises the following steps of: building a mathematical model which is connected with an active power filter system in parallel in a rotating coordinate system, calculating a reference value of a compensating current, decoupling the model into a pseudo-linear system, taking controlled variables of a main circuit switch function as input variables of the model, determining a reference voltage vector and an error current vector at the alternating current side of a main circuit as well as space regions at which the two vectors are located by virtue of the main circuit switch function, selecting a double hysteresis pulse width modulation method for an output voltage space vector to control the change rate of the error current vector, and adopting a DSP (digital signal processer) chip to realize the feedback linearization double hysteresis composite controller of the active power filter. By adopting the method disclosed by the invention, the problem of parameter coupling in a compensating current component in a system model is solved, thus a system can still rapidly respond under the condition that load parameters are disturbed or suddenly changed; meanwhile, the switching frequency of a main circuit inverter can be effectively reduced, and the switching loss can be reduced.

The invention discloses a wastewater treatment process adaptive generalized predictive control method. The method includes the following steps that: the design of an adaptive generalized predictive controller is realized through utilizing an idea of feedback linearization; and when the Lyapunov stability of the adaptive generalized predictive controller is proved, adaptive rules for correcting system controlled autoregressive integrated moving average (CARIMA) model parameters can be obtained, and the model parameters can be dynamically adjusted, so that a system tracking error can be minimum, and therefore, the steady-state control of dissolved oxygen concentration can be realized. With the wastewater treatment process adaptive generalized predictive control method of the invention adopted, the problem of incapability of ordinary generalized predictive control to realize stable control in response to large interference can be solved. As indicated by experimental results, the control algorithm can stably and fast control the dissolved oxygen concentration, has strong anti-interference ability, and is conducive to the stable and efficient operation of a wastewater treatment process.

The invention relates to a ship electric servo fin and wing fin rolling stabilization intelligent vector control method. The method includes the steps that a rolling detection device detects a rolling angle, the rolling angle and the rolling angular velocity of a system are estimated through a state estimator, and values obtained by subtracting the rolling angle and the rolling angular velocity from set values are sent to a feedback linearization controller; output of the feedback linearization controller is corrected through a self-adaptive controller based on a fuzzy tree, and then required rolling righting moment is obtained; corrected output signals are namely output signals of a rolling stabilization controller and are sent to a fin angle and wing fin angle intelligent optimizer, wherein the rolling stabilization controller is composed of the feedback linearization controller, the self-adaptive controller based on the fuzzy tree and an error observer; the fin angle and wing fin angle intelligent optimizer conducts angle distribution, generates real-time fin angle and wing fin angle instructions and sends the real-time fin angle and wing fin angle instructions to a fin and wing fin electric servo system; the fin and wing fin electric servo system is based on vector control and drives a fin and wing fins to rotate, the required righting moment is generated, and then rolling stabilization control over a ship is achieved.

The invention discloses a master-slave type cooperative control method for autonomous underwater vehicles. The method comprises the first step of regarding an external ocean current as external disturbance and conducting mathematical modeling on the external ocean current with regard to influences of the external ocean current, the second step of establishing an inertial coordinate system of a system and conducting vector resolution on relative speeds of the two underwater vehicles in the direction of a connecting line between the centroids of the two underwater vehicles and the direction perpendicular to the connecting line, and establishing a cooperative control motion model of the system, the third step of converting an original system motion model into a linear system model with the external disturbance through a feedback linearization method, and the fourth step of designing an optimal feedforward-feedback controller of the system motion model after conversion in order to suppress influences of the external disturbance. Through the master-slave type cooperative control method, one autonomous underwater vehicle can be controlled with high tracking accuracy and low driving energy to track the other autonomous underwater vehicle at a certain angle and distance on the condition of existence of the ocean current and other external disturbance, so cooperative control over the autonomous underwater vehicles can be achieved.

The invention discloses a sliding-mode control method for fuzzy PI parameter self-turning feedback linearization of an active filter. By a fuzzy PI parameter self-turning feedback linearization method, according to actual error in voltage control of the direct-current side of the active filter, fuzzy reasoning is performed according to a preset fuzzy rule so as to realize self-adaptive regulation of feedback linearization control law parameters, and accordingly, stability and adaptability of the voltage of the direct-current side are improved effectively. An integral position tracking sliding-mode controller is capable of effectively reducing harmonic content of supply current after compensation and improving harmonic compensation effect of the active filter. Further, since a synchronous coordinate transformation based unit sinusoidal-signal computing method is utilized, unit synchronous sinusoidal-signals can be computed accurately on the condition of high harmonics of supply voltage, and can be used for computing of reference supply current. The sliding-mode control method has the advantages that the harmonic compensation effect is good, the voltage of the direct-current side of the system has good dynamic and static characteristics, and system performance keeps good even when the power supply contains the harmonic voltage and non-linear loads change.

A positioning control system for an actuator provided with a strain wave gearing is provided with: a semi-closed feedback controller FB(s) that controls a load shaft position θ_l on the basis of a feedback motor shaft position θ_m; and a feedforward linearization compensator configured by incorporating a nonlinear plant model for an object to be controlled into a feedback linearization compensator using an exact linearization technique. The feedforward linearization compensator uses a forward-calculated state quantity estimated value x* to calculate a feedforward current instruction i*_ref and a feedforward motor position instruction θ*_m to be input into the feedback controller FB(s). A positioning error caused by a non-linear element (non-linear spring property, relative rotational synchronization component, and non-linear friction) of the strain wave gearing is compensated for by the feedforward linearization compensator.