75 results about "Smith predictor" patented technology

An image fixing apparatus controls temperature of a rotating member for fixing with compensation for delay by using a Smith predictor with a controlled object model to reduce temperature ripple effectively. In one example, the image fixing apparatus includes a pair of rotating members to form a nip portion, a heater to heat the rotating member, a temperature sensor to detect temperature of the rotating member, a calculator to calculate a heat value to attain a target temperature of the rotating member, a controller to control the heater based on a calculation result of the heat value with compensation for delay using a model according to the calculation result, and a selector to select a control in which an output of the compensation is input into the calculator or a control in which the output of the compensation is not input into the calculator.

The invention discloses a hydraulic AGC system of a rolling mill, and a control method thereof, and the system is connected to be formed in a manner of double closed loop of an inner-outer loop that is combined by an outer closed loop and an inner single closed loop. A thickness measuring device is taken as a feedback element, a deviation signal of the feedback value of the thickness measuring device and a given thickness value is firstly input into a PID controller which is based on Smith predictor function and then is input into the PID controller in the inner single closed loop, the deviation signals of a position sensor, a pressure sensor, a tension sensor and the feedback value of an speed measuring device are input into the PID controller; the PID controller processes the signals by a control module, and a touch screen HMI device is used for setting and displaying the parameters of the system and operating and monitoring all the steps. As the strategy of the PID controller based on Smith predictor function is introduced in the invention, the feedback and response speed is fast, thus improving the control precision and stability of the system obviously. The system and the method have the advantages of simple installation and debugging, convenient operation and reliable running.

An engine with inertial integration and delay is controlled through the use of a disturbance estimator. Control logic includes a feed-forward control path driving a control input with a control signal. The feed-forward control path is designed to provide closed-loop control of the controlled parameter without the presence of transport delay. The disturbance estimator generates an estimate of the engine disturbance. A Smith predictor generates a compensation signal for the feed-forward control path based on the control signal and the engine disturbance estimate.

The invention relates to an automobile engine thermal management system modeling and control method, and belongs to the technical field of control. The aim is to provide an engine thermal management system dynamic modeling method and a water temperature control method. In the system dynamic modeling method, an accurate heating power model of an air cylinder to an inner wall, a heat exchange coefficient model of a water jacket and cooling liquid and a radiating power model of a radiator are built. The research method of the method comprises the following steps that according to the structure, the principle and measurable signals of an engine thermal management system, a system dynamic model is built; seen from the heat convection heat exchange and radiation heat exchange mechanisms, three intermediate variables in the dynamic model are derived; a system inverse dynamic model is derived according to the system dynamic model; a Smith predictor is designed according to the system dynamic model; and a PD feedback controller is designed. The dynamic model of the engine thermal management system is accurately built, and the control accuracy is improved.

A method and system for providing a feedback based dynamic pricing algorithm with an embedded controller for a HOT (High Occupancy Toll) lane. An input-output transfer function of a vehicle flow with respect to a HOT lane can be obtained utilizing a simulation module. A feedback controller combined with, for example, a Smith predictor can be designed to avoid an unstable behavior due to a time delay in the HOT lane, a price regulation, and a large transient caused by an integral part of the controller due to traffic jams. A driver behavior preference model can be derived based on a relationship between a toll rate and several characteristics of the HOT lane and a general purpose lane. The feedback controller and the behavior preference model can then be implemented to set the toll rate in real-time in order to satisfy a desired performance metric.

The invention provides a temperature control method for a projection objective of a photoetching machine, where the objective temperature is regulated to a set value of the objective temperature by use of a temperature control unit (TCU), comprising the following control steps: initializing system parameters, deciding to enter which control step: pre-regulating the TCU inner water temperature to a set value; using switch control, with the objective temperature as a master control variant, controlling the objective temperature in a target accuracy of step P2; using a cascade control arithmetic with a Smith predictor, with the objective temperature as the master control variant, using an increment PID arithmetic, and a water temperature at a flow plate as a secondary control variant, using an increment PI arithmetic for the secondary control loop; using a cascade control arithmetic without a Smith predictor, with the objective temperature as a master control variant, using an increment PI arithmetic for the master control loop, and the water temperature at the flow plate as a secondary control variant, using the increment PI arithmetic for the secondary control loop; using the increment PI arithmetic, where the control variant is the water temperature at the flow plate.

The invention provides a modified Smith prediction main stream temperature control structure. The modified Smith main stream temperature control prediction structure is characterized by a system transfer function. The another technical scheme includes that a novel Smith predictor is added, and a modified Smith main stream temperature prediction structure is provided and characterized by a system transfer function. The modified Smith prediction main stream temperature control structure has the advantages that the function transferring manner that the one-order inertia adds the delay link of the conventional Smith predictor is replaced by the high-order system, allowing the prediction system stable, thus dynamic deviation of the system is decreased and engineering application is convenient.

The invention discloses a dissolved oxygen control method based on a fuzzy neural network. The method comprises the following steps: S1, modeling is carried out; S2, fuzzy identification is carried out, and a fuzzy identification method is adopted to identify the structure and parameters of an object model; S3, a clustering method is adopted to determine the number of rules; S4, a neural network is used for learning reasoning data of an expert, a fuzzy reasoning rule is acquired, and each connection weight is adjusted at the same time; S5, after a least square method is used for order identification, a transitive closure method is used for clustering analysis according to a fuzzy similarity relation; S6, a Smith predictor is introduced; and S7, two independent control circuits of blower pressure and oxygen dissolution are adopted. The wastewater treatment effects are good.

The reason why a time delay system is difficult to control is that information feedback is not timely, thus a controller based on feedback information seems to be powerless to the kind of systems. Aiming at the control problem of the time delay systems, a predictive wisdom proportional-integral (PWPI) control method that does not depend on a controlled object model is invented. The PI control method regards nominal model parameters of a time delay object as model parameters of a Smith predictor, combines output of the Smith predictor with actual output of the object to form compensation outputof the system, designs a predictive wisdom PI controller, determines speed factors of the PWPI controller according to a time delay estimated value and a time constant nominal value, theoretically analyzes the stability of a closed-loop control system and the robustness of the controller, is an effective control method, and has a wide application value in the field of time delay system control.

The invention discloses a compensation method suitable for uncertain large time delay of a new energy electric generator. The compensation method comprises the following steps: using a parameter adaptive control method of Fibonacci sequence and time scale to establish a linear ADRC, and outputting a controlled quantity of a grid-connected inverter; using a mutual correlation method and a sliding window digital signal processing method, and calculating and obtaining uncertain large time delay according to the controlled quantity and the output current of the grid-connected inverter; adopting a Smith predictor to calculate and obtain the controlled quantity of the grid-connected inverter of the new energy electric generator, so as to realize compensation of the large time delay and the adaptive robust control of the new energy electric generator. The compensation method can accurately estimate the uncertain large time delay of the new energy electric generator, reduces the overshoot of the output current of the new energy electric generator, shortens the regulating time, and improves the operational stability and the robustness of the new energy electric generator.

The invention discloses a control method and system for assisting the secondary frequency regulation of a thermal power unit by using an energy storage device. The control system adopted by the invention comprises a power control module based on the state-of-charge of an energy storage device and a time delay compensation module based on a Smith predictor. The control system receives the secondaryfrequency modulation command from the power grid, the active power feedback of the thermal power unit, the state of charge of the energy storage device and the active power feedback of the output. According to the feedback data, the control system adopts the method based on the state of charge of the energy storage device to determine the active power output of the energy storage device. A Smithpredictor is use to compensate the time delay in the auxiliary frequency modulation system, the control system obtains command power, and the command is sent to an energy storage device through a communication device, and the power generation power of a thermal power unit is compensated by utilizing the quick response characteristic of the energy storage device; The auxiliary frequency modulationsystem comprises a control system and an energy storage device. The invention can improve the dynamic performance of the thermal power unit participating in the frequency modulation of the electric power system and obtain higher frequency modulation income.

The invention discloses an electric heating furnace temperature control method based on improved fuzzy Smith-PID. The method comprises the steps that firstly, the actual temperature of the electric heating furnace is collected through a temperature sensor and compared with a given value to obtain a temperature deviation value and the change rate of the deviation value; performing fuzzy reasoning to obtain three control parameter setting quantities so as to calculate a control signal of the electric heating furnace through a PID controller; an improved Smith predictor is added in the system forpredictive compensation, and a nine-point control method is used for adjusting a filtering time constant of a feedback channel of the Smith predictor. According to the method, the traditional PID isreplaced by the parameter self-tuning fuzzy PID, so that the overshoot of the system is reduced, and the robustness of the system is improved. On the basis of a traditional Smith predictor, a nine-point control method is introduced into a time delay system, real-time online adjustment is carried out on a filtering time constant of a feedback channel, and the influence caused by mismatching of a prediction model is relieved while a lag link is compensated.

The invention provides a method and device for controlling the temperature of an SCR reactor. The method for controlling the temperature of the SCR reactor includes the steps that an SCR dynamic temperature model is established according to the experimental measurement temperature before the SCR reactor and a two-point method with a delay first-order inertia link fitting function; a Smith predictor is used for conducting calculation to obtain a compensation value according to the characteristics of the SCR dynamic temperature model; the compensation value can eliminate a lag link in the SCR dynamic temperature model; a difference value obtained by subtracting the sum of output of the SCR dynamic temperature model and the compensation value from the preset temperature of the SCR reactor is calculated; a feedback signal containing the difference value is received, the rear fuel injection quantity of an engine is calculated according to the difference value, a signal containing the rear fuel injection quantity of the engine is sent to the engine, and the engine is controlled to conduct rear injection according to the rear fuel injection quantity so as to control the temperature of the SCR reactor. According to the method, the stability of control over the temperature of the SCR reactor is improved.

In the present invention, a Smith predictor enhanced PID controller, SP-PID, is proposed. A tuning parameter K_sp is devised and the SP-PID controller would be gradually transformed from a PID controller to a Smith predictor as K_sp changes from 0 to 1. Properties of the SP-PID are explored and the design procedure is given to ensure a certain degree of robustness. Simulation results clearly indicate that the SP-PID takes advantage of the SP when small modeling error is encountered and it is gradually detuned to a PID controller, a user-friendly controller, when the model quality degrades. Moreover, the controller and its design procedure can be implemented in current process control computers with virtually no extra hardware cost.

The invention provides an electricity network harmonic current signal tracking control method based on time delay compensation. The harmonic current signal tracking control method based on the time delay compensation is provided by aiming at the influence of the time delay control on a system and using an IHAPF (injection type hybrid active power filter) as a study object. According to the method, an improved smith predictor and a neural network PI controller are mainly used, wherein through the smith predictor, the system time delay process is converted from the inside of a control closed loop to the outside, so that the influence of the time delay control on the system is reduced; meanwhile, a PSO-BP algorithm is used for performing optimization processing on the PI controller parameters; a mathematical model between the smith predictor and the PI control parameter can be built according to an ITAE (integral time absolute error) criterion; finally, the mathematical model and the neural network are in optimized matching to obtain the optimum parameter of two controllers.

The invention discloses a main steam pressure self-adaptive predictor of a generator set of a circulating fluidized bed boiler, which solves the problem that the stable control of the main steam pressure of the generator set of the circulating fluidized bed boiler is difficult to realize. A gain self-adaptive Smith predictor is constructed according to the Smith prediction principle, by utilizing the total coal supply quantity, the actual main steam pressure, and the opening of a control valve of a steam engine of the boiler as three input variables of the Smith predictor, the output of the predictor serves as predicted main steam pressure of the generator set, and a deviation between a predicted main steam pressure value and a main steam pressure set value is calculated and used as an input deviation of a master control PID of the boiler in coordination control. In a steady state, the predicted main steam pressure is equal to the actual main steam pressure, in a dynamic state, the predicted main steam pressure integrates a value of the influence of the total coal supply quantity of the generator set and the opening of the control valve of the steam engine on the main steam pressure, and under variable loads, due to the changes of the total coal supply quantity and the opening of the control valve of the steam engine, the input deviation of the master control PID of the boiler is timely eliminated, so that the master control of the boiler rapidly enters a new stable state.

The invention discloses a self-sufficient type internal combustion engine gas fuel supply system and a gas packet pressure control method. The system comprises an LNG tank, an LNG supply pump, an LNG vaporizer, a gas pocket and an NG injection valve. During work, liquefied natural gas stored in the LNG tank flows to the shell pass of the LNG vaporizer under the action of the LNG supply pump, absorbs heat on the shell pass and becomes gaseous natural gas to be stored in the gas pocket. The NG injection valve is used for injecting a quantitative amount of gas fuel to a gas inflow channel. Heat-transfer mediums circulated in the medium-high temperature segment in a cooling system flow into the tube pass of the LNG vaporizer through a heat transfer medium three-way valve and flow back to a low temperature segment of the cooling system after releasing heat, the heat transfer mediums flow into a cylinder sleeve of an internal combustion engine to absorb heat again, and circulation is unceasingly performed in this way. According to the method, a fuzzy controller, a Smith predictor and an artificial immunity controller, the LNG supply flow and the heat transfer medium flow can be dynamically optimized well according to gas packet pressure and NG flow changes, the gas pocket pressure can be stabilized within a given area, and influences caused by nonlinearity and time lag of the system are well eliminated.

The invention belongs to the technical field of bandwidth resource limited MIMO-NCSs (multiple-input multiple-output networked control systems) and relates to a two-input two-output networked control system delay compensation SPC (smith predictor control) and IMC (internal model control) method. In order to solve the problems that two-input two-output signals in a TITO-NCS (two-input two-output networked control system) have mutual effect, network delay due to the transmission of network data between nodes affects the stability of one closed-loop control circuit of the system and may also affect the stability of another closed-loop control circuit while even stability loss is caused to the TITO-NCS, it is presented that an inter-node network delay compensation model is replaced by network data transmission process between all true node s in the TITO-NCS, with dynamic feedforward as well as SPC and IMC applied to the two circuits; by using the method of the invention, it is possible to omit the measurement, estimation or identification of inter-node network delay, omit the requirement on node clock signal synchronization, reduce the effect of network delay upon TITO-NCS stability, and improve the control performance quality of the system.

The invention discloses a control system for adjusting the opening degree of an electronic expansion valve so that an effective implementation plan of controlling the opening degree of an electronic expansion valve can be searched. The control system comprises an input terminal IN, a first multiplier, an electronic expansion valve, and a feedback module, a Smith fuzzy PID controller for generatingcontrol information for controlling the opening of the electronic expansion valve, an evaporator, and an output terminal OUT. The input terminal IN, the first multiplier, the Smith fuzzy PID controller, the electronic expansion value, the evaporator, and output terminal OUT are connected in sequence. According to the invention, a fuzzy controller applied to a fuzzy control algorithm to set control information of the PID controller in real time and a Smith predictor compensator for reducing the control lag of the electronic expansion valve are fused based on the PID controller. Therefore, thecontrol system has advantages of strong fuzzy control adaptability, insensitivity to model accuracy, and strong robustness and the like.

The invention relates to a prediction active disturbance rejection control strategy for finite time convergence of a compression type refrigerating system, which comprises the following steps: establishing a mathematical model of the compression type refrigerating system; decoupling the model of the compression type refrigeration system into two independent control loops; constructing a Smith predictor, and feeding back by using the prediction output of the Smith predictor; constructing a nonlinear extended state observer with finite time convergence; and constructing an active disturbance rejection controller to realize the function of predicting active disturbance rejection control. Aiming at the characteristics of big time lag, strong coupling, multivariable, time variation and the likeof the compression type refrigeration system, the Smith predictor is combined with the active disturbance rejection control with finite time convergence, a prediction active disturbance rejection control strategy with finite time convergence is realized, the unmodeled dynamics, uncertain items, dynamic coupling and external disturbance of the refrigeration system can be estimated and compensatedas total disturbance, and the stability of the system is improved.

The invention belongs to the field of thermal generator set flue gas denitrification control technologies, and discloses a control system and a control method for boiler denitration outlet nitrogen oxide content. The control system comprises an SCR reactor, a main PID controller, an auxiliary PID controller and a Smith predictor, wherein the main PID controller and the auxiliary PID controller adopt a cascade connection method for control; an output end of the main PID controller is connected with an input end of the Smith predictor, an output end of the Smith predictor acts on an input end of the main PID controller; and the main PID controller controls nitrogen oxide concentration of an outlet of the SCR reactor, and the auxiliary PID controller controls ammonia spraying flow entering the SCR reactor. The control system and the control method can solve the problems of large delay and great inertia of the existing denitration system.

The invention discloses a closed-loop control method of cold-rolled sheet shape based on lag compensation. The closed-loop control method comprises the specific steps of manufacturing a structure of a sheet shape closed-loop control system based on a multivariate optimization model; designing the multivariate optimization model of the sheet shape closed-loop control system; manufacturing PID control models of all sheet shape regulating mechanisms; manufacturing PID+Smith predictor control models of all the sheet shape regulating mechanisms; determining process models of control circuits of all the sheet shape regulating mechanisms, and setting corresponding PID parameters; and establishing control modes of the sheet shape closed-loop control system. The closed-loop control method has the advantages that the influence of measurement lag to the stability of the sheet shape closed-loop control system during sheet shape control process can be removed through switching the sheet shape closed-loop control modes according to the rolling speed change, the structure is simple, the calculation efficiency is high, the control real time performance is relatively high, the stability of the sheet shape closed-loop control system is not influenced by measurement lag, and relatively high homeostatic control accuracy is achieved.

The present invention discloses a two-phase orthogonal inversion power source control method enabling a delay compensation function. According to the method, an iterative learning algorithm is added to the feedback control link of current; the quick compensation output of the current can be realized through repeatedly applying information obtained in previous experiments, and therefore, the response performance of the output alternating current of a PWM inverter can be improved, and control quality can be also improved; as for a condition that the delay of a control system influences output current dynamic tracking performance and the stability of a system, a Smith predictor is introduced to eliminate the delay influence of the control system; and in fact, the Smith predictor estimates a lag link and makes appropriate compensation, so that a closed-loop characteristic equation does not contain the lag link, thus the dynamic characteristic and stability of the system can be improved. The control method of the present invention can significantly improve the stability and response speed of a system as for electromagnetic stirring which requires frequent positive and negative rotation alternation.