440 results about "Variable structure control" patented technology

The present invention is directed to a direct-drive fan system and a variable process control system for efficiently managing the operation of fans in a cooling system such a as wet-cooling tower or air-cooled heat exchanger (ACHE), HVAC systems, mechanical towers or chiller systems. The present invention is based on the integration of key features and characteristics such as tower thermal performance, fan speed and airflow, motor torque, fan pitch, fan speed, fan aerodynamic properties, and pump flow. The variable process control system processes feedback signals from multiple locations in order control a high torque, variable speed, permanent magnet motor to drive the fan. Such feedback signals represent certain operating conditions including motor temperature, basin temperature, vibrations, and pump flow rates. Other data processed by the variable process control system in order to control the motor include turbine back pressure set-point, condenser temperature set-point and plant part-load setting. The variable process control system processes this data and the aforesaid feedback signals to optimize the operation of the cooling system in order to prevent disruption of the industrial process and prevent equipment (turbine) failure or trip. The variable process control system alerts the operators for the need to conduct maintenance actions to remedy deficient operating conditions such as condenser fouling. The variable process control system increases cooling for cracking crude and also adjusts the motor RPM, and hence the fan RPM, accordingly during plant part-load conditions in order to save energy.

The invention discloses a sensorless control system of a permanent magnet synchronous motor. The sensorless control system comprises a flux linkage/current state observer and a counter electromotive force measurement module, wherein the flux linkage/current state observer is a sliding mode observer; the sliding mode observer is controlled by a sliding mode variable structure; and the coordinate system of the sliding mode observer is an estimated rotary coordinate system, is rotated at an angular speed and lags behind an electrical angle of the coordinate system. In a control parameter computation module, the error of a rotor position is calculated. The sensorless control system of the permanent magnet synchronous motor, can be used on a low-speed observation occasion and a height observation occasion at the same time and has strong practicability.

The invention relates to a method for controlling a rigid spacecraft for target attitude tracking, and belongs to the technical field of the high-precision and high-stability attitude tracking control of spacecrafts. The method solves the problem that when the attitude tracking spacecraft runs in a low orbit in outer space, the conventional control method cannot eliminate the inherent flutter of a sliding mode variable structure. The method comprises the following steps: 1, establishing a kinetic model and a kinematic model of the rigid spacecraft; 2, setting an attitude tracking error and anexpected attitude parameter of the rigid spacecraft, and combining the attitude tracking error and the expectation attitude parameter with the kinetic model and the kinematic model to establish a mathematical model for the attitude tracking; 3, adopting a control algorithm of a sliding mode variable structure controller to adjust a control law of the mathematical model which is established in thestep 2 and is used for the attitude tracking, and simultaneously combining an observation result of a disturbance observer to modify the control law; and 4, controlling the rigid spacecraft by using the modified control law obtained in the step 3 to realize the attitude tracking. The method is suitable for the attitude tracking of targets running in the outer space.

The invention discloses an attitude control method. The attitude control method comprises the following procedures that the on-satellite time influencing the satellite attitude precision is aligned through a second pulse signal; a satellite sensor error used for satellite attitude measurement is corrected in real time; the gravity gradient disturbance torque of an oblique flying satellite is compensated through a dynamics coupling relationship; the satellite flexibility is restrained through an input forming control method in the attitude controlling process; the attitude control law of an angular velocity feedforward instruction is increased through position and speed double loops and a position correcting loop to achieve high-precision and high-stability attitude guidance control; and quick attitude maneuver of the large-inertia satellite is achieved through a saturated sliding mold structural control algorithm. The attitude control method has the advantages that the computing method is simple, control is flexible, the attitude control method can be applied to attitude control of the large-inertia large-flexible oblique flying satellite, the property of the satellite is greatly improved, and researching and manufacturing cost of satellite hardware is reduced.

The invention provides a wheel longitudinal force regulation-based vehicle handling stability control method; the control method is applied to a vehicle with a mechanical steering system and without an active steering function. The control method comprises the following steps: (1) according to a signal input by a driver and a vehicle speed state, calculating a vehicle reference motion state by a vehicle reference model; (2) according to a vehicle motion state measured by a vehicle-mounted sensor, estimating to acquire a non-measured vehicle motion state as a vehicle real motion state; (3) based on sliding mode variable structure control, acquiring a target control force and a target control moment which are needed for the vehicle real motion state to track the reference motion state; (4) by regulating longitudinal force of the wheels, generating the needed target control force and target control moment. According to the control method, by regulating the longitudinal force of the wheels, nonlinear combined control on vehicle speed, yaw velocity and side slip angle can be realized, and the vehicle handling stability is improved.

The present invention is directed to a load bearing direct-drive system for driving a fan in a cooling system such as a wet-cooling tower, air-cooled heat exchanger, HVAC system, hybrid cooling tower, mechanical tower or chiller system. The present invention includes a variable process control system that is based on the integration of key features and characteristics such as tower thermal performance, fan speed and airflow, motor torque, fan pitch, fan speed, fan aerodynamic properties, and pump flow. The variable process control system processes feedback signals from multiple locations in order to control a high torque, low variable speed, load bearing motor to drive the fan.

The invention discloses an inversing global SMFC (sliding mode fuzzy control) method for a micro-gyroscope based on a neural network. An inversing global SMFC system based on the neural network consists of an inversing global sliding mode fuzzy controller, a neural network dynamic characteristic estimator, and a fuzzy uncertainty estimator. Global sliding-mode control can iron out a defect that an arrival mode in the conventional sliding-mode control does not have robustness, speeds up system response, and enables a system to have robustness in the whole process of response. The method enables a lyapunov function of the system and the design process of a controller to be systematic and structuralized through inverse design during the inversing control. Fuzzy control is used for approximating a switching function term, and a switching term in sliding-mode control is converted into continuous fuzzy control output, thereby weakening vibration in sliding-mode control, and achieving a stronger capability of adaptive tracking. Therefore, the method improves the transient performance and robustness of a sliding-mode control system, estimates the unknown dynamic characteristics of the micro-gyroscope, and reduces the vibration in the control of a sliding-mode control structure.

The invention discloses a permanent magnet synchronous motor chaos control method based on a nonlinear expanded state observer. The permanent magnet synchronous motor chaos control method comprises the steps of: building a chaos model of a permanent magnet synchronous motor system, and initializing a system state and related control parameters; through coordinate transformation, converting the chaos model of the permanent magnet synchronous motor system to be Brunovsky standard form that is more suitable for designing the nonlinear expanded state observer; designing the nonlinear expanded state observer for estimating the unpredictable system state and parameter perturbation; designing a self-adaptive sliding mode variable structure controller, improving problem about buffeting in sliding mode control, and ensuring that the chaos state of the system is rapidly and stably converged to zero according to the system state and parameter perturbation estimated by the nonlinear expanded state observer.

The invention discloses a patient movement demand-based assistance lower limb rehabilitation robot self-adaptation control method. By collecting the joint angle and joint angle speed signal of the lower limb of a patient in real time, the expected track self-adaptation tracking control is realized by a robustness variable-structure control method; then, by using a man-machine dynamics system model, the rehabilitation degree and the active movement ability of the patient are studied in real time by using a RBF (Radial Basis Function) neural network; the forward feed assistance of a lower limb rehabilitation robot is further estimated; next, the real-time assistance of the robot is subjected to self-adaptation attenuation according to the track tracking errors; the continuous self-adaptation patient rehabilitation demand-based assistance control is realized; finally, the tracks subjected to the patient rehabilitation demand-based assistance self-adaptation control correction are input into a lower limb rehabilitation robot joint movement controller; the on-line movement is performed; and the continuous and seamless patient rehabilitation demand-based assistance lower limb rehabilitation robot self-adaptation control is realized.

The invention relates to a permanent magnet synchronous motor drive control system, in particular to the permanent synchronous motor drive control system used for a servo system. The permanent synchronous motor drive control system belongs to the technical field of motor control. The permanent synchronous motor drive control system consists of a power module, a central control unit, two analogue signal processing units, two digital signal processing units, a current measurement module, a rotating speed measurement module, an overcurrent protection processing unit, an isolation unit and a power amplification unit. A drive strategy of the central control unit adopts a space vector pulse width modulation technology, and a speed loop controller with an integral time-varying sliding mode variable structure is designed in a digital signal processor (DSP) controller of the central control unit. Compared with the conventional control system, the permanent magnet synchronous motor drive control system has higher speed, enhanced anti-jamming capability and enhanced system parameter perturbation robustness; and the sliding mode of sliding mode variable structure control can be designed, and is insensitive to disturbance to the system and parameter variations, so the sliding mode variable structure control has the characteristics of high robustness, quick response, easily implemented comprehensive method and the like.

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.

The invention discloses a permanent magnet synchronous motor predicted current control method and system based on FOSMC; the method comprises the following steps of carrying out comparing on the rotorangular speed and a given rotating speed to obtain a rotating speed difference, and inputting the rotating speed difference into a fractional order sliding mode controller; next, enabling an equivalent current of a dq axis at the current moment to pass through a sliding mode disturbance observer to obtain a voltage compensation quantity and a current estimation value under the parameter change, and enabling the current estimation value and the reference current at the next moment to be input into a non-differential-beat current prediction controller; and finally, carrying out compensating onthe obtained voltage vector and the voltage compensation amount of the dq axis at the current moment, carrying out coordinate transformation, space vector modulation and inversion, and obtaining a three-phase voltage to the permanent magnet synchronous motor, so that the stable operation of the motor is ensured. According to the method and the system disclosed by the invention, fractional order calculus and sliding mode variable structure control are combined, the fractional order calculus has more freedom degree, and the shaking of the system in the sliding mode process can be weakened, so that the control precision of the rotating speed is improved.

The invention discloses an UUV four degree-of-freedom dynamic positioning adaptive anti-interference sliding mode control system and a control method. The system comprises a first differentiator, a second differentiator, an adaptive anti-interference sliding mode controller, a filter and data fusion unit, a Doppler sensor, an electric gyrocompass, a thrust allocation unit, an UUV, an accelerometer and a gyroscope , wherein the adaptive anti-interference sliding mode controller comprises a sliding mode controller, an adaptive disturbance compensation controller and a data processing unit; the sliding mode controller is used for realizing UUV four degree-of-freedom dynamic positioning variable structure control and eliminating pose errors; and the adaptive disturbance compensation controller is used for estimating uncertainty errors of an actually controlled object model and wave disturbance effects in an online mode. A dynamic process during which the system state approaches to the sliding mode surface is improved, steady-state anti-interference performance is improved, and compared with a common sliding mode control method, dynamic performance is better, and buffet of the system under disturbance effects can be reduced.

The invention discloses a control system of a high frequency switching power supply for a Cz silicon single crystal furnace and a control method. The control method includes the steps of combining self-adaptive fuzzy control and sliding mode variable structure control, and aiming at a high-frequency switch heating electric power for the Cz silicon single crystal furnace to design a power controller based on a self-adaptive fuzzy control and sliding mode variable structure control method. The control system of the high frequency switching power supply for the Cz silicon single crystal furnace and the control method play respective advantages of fuzzy control and sliding mode variable structure control, further improve dynamic performance of the system, have good robustness for input voltage or load disturbance, and relieve or avoid vibration which generally happens to a sliding mode.

The invention relates to a sliding mode variable structure control method for a low-speed friction servo system which is based on a gray predictor. The method comprises two stages: the first stage, the sliding mode variable structure control method of the exponential approach rate is adopted to control the servo system, simultaneously, the gray control theory is utilized to estimate the uncertain part of the servo system and the outside unknown interference model parameter; the second stage, after former steps, based on the control law at the first stage, the gray predicting compensation control quantity can be calculated according to the estimate parameter, and can take part in controlling the servo system along with the control quantity of the fist stage. The control method can guarantee the low-speed friction servo system to also obtain better robust even though the effects of the uncertain part and the outside unknown interference model parameter are considered, so as to reach high precision tracing effect. The control method has the simple and pellucid program, provides a new control strategy for systems which have nonlinear and uncertain control objects as well as outside unknown interference, thereby having certain practical engineering value.

The invention discloses a wide-range bidirectional conversion circuit and a control method. The wide-range bidirectional conversion circuit comprises a three-stage bidirectional converter and a control unit, and the three-stage bidirectional converter is formed by sequentially connecting a non-isolated DC/DC converter, an isolated DC/DC converter and a DC/AC inverter. When the system works in theforward direction, a direct-current power supply or energy storage equipment realizes grid-connected energy feedback through the non-isolated DC/DC converter, the isolated DC/DC converter and the DC/AC inverter; and during reverse working, an alternating voltage supplies power to a direct-current load or charges an energy storage device through a rectifying circuit, the isolated DC/DC converter and the non-isolated DC/DC converter. In order to adapt to different power levels and realize higher input current ripple control, the non-isolated converter adopts a multi-phase interleaved parallel structure; and in order to further broaden the requirements of input and output ranges in practical application, the isolated converter can be controlled by adopting a full-bridge/half-bridge variable structure. The whole system has the advantages of wide input direct-current voltage range, wide output alternating-current voltage range, wide load range, small current ripple, high-frequency isolation, high efficiency, energy conservation, environmental protection and the like.

The invention discloses a two-wheeled self-balance robot self-adaptive sliding mode changing structure control method and system. According to a classical mechanics analytic method and based on a Lagrange algorithm based on energy analysis, molding of a kinetic equation of a two-wheeled self-balance robot of is realized, a sliding mode changing structure controller is designed according to the kinetic equation. The sliding mode changing structure controller comprises a speed sliding mold changing structure controller and an angle sliding mold changing structure controller; the speed sliding mold changing structure controller and the angle sliding mold changing structure controller give each other feedbacks; a feedback equation is that theta r=beta V; and self-adaptive controlling is carried out on the system on the basis of a function approximation mode. Through adoption of the technical scheme of the present invention, the modeling process is enabled to be more simplified and comprehensive; the robustness and the respond speed of the system are raised; simultaneously, since a mutual feedback relation exists between the speed and the angle of the system, when an inclination angle of the system is overlarge, the system will automatically decelerate; while the speed is reduced, the system will return to the balance position; in a condition of facing different road surface conditions, the system can adapt to external environment and large scope load changes, thereby guaranteeing the safety and stability of the system.

The invention discloses a sliding-mode variable structure control method of a single phase grid-connected inverter based on a multi-resonant sliding mode surface. The method comprises the steps of: firstly, building a linear sliding mode surface according to detected current i1 of an inverter side filter inductor of the single phase grid-connected inverter, the voltage vc of a filter capacitor, the current i2 of a network side filter inductor, and the target output current i1* of a grid-connected inverter system, the target voltage vC* of the filter capacitor and the grid-connected target current i2*; adding a resonant item into the linear sliding mode surface so as to obtain the multi-resonant sliding mode surface; designing a sliding-mode variable structure controller by the multi-resonant sliding mode surface, leading a linear state feedback controller to an original nonlinear controller to obtain a final control quantity modulation wave d(s), and finally comparing the modulation wave with a carrier wave to generate a driving signal for driving a switch tube to act. According to the control method disclosed by the invention, the robustness and dynamic response ability of the grid-connected inverter system are improved; the tracking accuracy of grid-connected current is also improved; the harmonic content is removed, and the control method is simple and easy to achieve.

The invention relates to a road surface self-adaptive driving anti-skid control method and system of a distributed driving electric automobile and belongs to the technical field of vehicle control. According to the road surface self-adaptive driving anti-skid control method of the distributed driving electric automobile, by estimating a current road surface peak adhesion coefficient in real time,a current road surface optimal slip rate is obtained according to a corresponding linear relation between the current road surface peak adhesion coefficient and the current road surface optimal slip rate; by combining a current wheel center speed, a current wheel reference wheel speed is determined; a difference between an actual wheel speed and the reference wheel speed is calculated; according to the wheel speed difference, the moment of a wheel, which slips in a driving state, is controlled by using a sliding mode variable structure controller; and therefore, it is guaranteed that the wheelslip rate is controlled to the current road surface optimal slip rate. According to the road surface self-adaptive driving anti-skid control method of the distributed driving electric automobile, thewheel slip rate is controlled to the current road surface optimal slip rate to realize self-adaptive control of anti-skid driving of the wheel.

The invention provides a method for controlling a slip mode variable structure of a brushless direct current motor based on a power exponential reaching law. The method comprises the following steps of S1, analyzing a mathematics model of the brushless direct current motor; S2, designing a slip mode controller; combining a power reaching law and an exponential reaching law, so as to obtain the improved reaching law-power exponential reaching law, and calculate the slip mode control rate at the current time; S3, setting a current loop and a speed loop for controlling the brushless direct current motor, wherein the current loop adopts the integral and proportional control type, and the speed loop adopts the slip mode variable structure control type using the power reaching law; S4, repeatedly updating the value of slip mode control rate i, so as to control the brushless direct current motor. The method has the advantages that the control quantity on the brushless direct current motor adopts three adjustable parameters, so that the control and adjusting are more flexible; a control strategy with high control quality, simple type and convenient implementing on the brushless direct current motor is provided.

The invention discloses a high-voltage direct-current power transmission multi-channel supplementary damping control method based on a variable structure. The high-voltage direct-current power transmission multi-channel supplementary damping control method has the characteristics that sub-synchronous and low frequency oscillation frequencies and damps, and a system reduced-order model are identified by a TLS-ESPRIT (Total Least Squares-Estimation of Signal Parameters via Rotational Invariance Techniques) algorithm with high operation efficiency and anti-interference capability; a variable structure control principle is combined and an attached controller containing a virtual state variable is designed; finally, a state observer is led in to eliminate the virtual state variable so as to realize an HVDC (High Voltage Direct Current) variable structure controller with an output feedback form; then a variable structure control theory is used for designing a multi-channel direct-current attached damping controller so as to reduce the mutual influences between oscillation modes; the sub-synchronous and low frequency oscillation can be inhibited synchronously. The method is efficient and feasible; the variable structure control theory has strong disturbance rejection on complicated changeable working conditions of an actual power grid; meanwhile, a multi-channel structure is utilized by using the controller to solve a coordinated control problem among the plurality of controllers; the invention provides a controller design method of an actual large power grid with very strong operability.

The invention discloses an ESO-based control method of a double-fed wind power generation system integral sliding mode controller, and is implemented according to the following steps: first a mathematical model of a double-fed wind power generation system is written; after the mathematical model is obtained, on this basis an extended state observer based on the double-fed wind power generation system is designed according to the principle of the extended state observer; then, a switching function of a controller of a sliding mode variable structure is determined; and finally, according to a control objective that a system error is reached in limited time and maintained on a sliding mode surface, the sliding mode control law is obtained. Feasibility of the strategy is verified through simulation. According to the ESO-based control method of the double-fed wind power generation system integral sliding mode controller, the extended state observer-based sliding mode variable structure control strategy is researched, thereby realizing decoupling control in the running process of the double-fed wind power generation system, improving corresponding speed of the system, and enhancing parameter robustness of the system.

The invention discloses a magnetic-levitation train suspension control method based on sliding mode variable structure control. The method comprises the steps that according to a kinetic equation of amagnetic-levitation train suspension control system, an electromagnet voltage equation and changes of a railway action surface, a dynamic model equation of the system is built; by using the linearized theory, the magnetic-levitation control system is analyzed and designed to obtain a nonlinear equation set, and the nonlinear equation set is approximated into a linearized model; according to the approximated model, the stability of the system is judged, an appropriate state variable is selected, the state variable which can be directly measured is selected as a feedback variable, and the feedback variable is subjected to state feedback control; the fundamental principle of a sliding mode control algorithm is analyzed and utilized, the magnetic-levitation control system model based on sliding mode control is built, and by adopting an appropriate control law, a design structure of a suspension controller is given. By means of the method, the performance of the controller in the suspension control system of a magnetic-levitation train can be improved, and the method can well meet the requirements for high response, stability and anti-interference performance in the suspension processof the magnetic-levitation train.