557 results about "Nonlinear control" 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.

System and method for managing batch fermentation in biofuel production. An optimizer executes a nonlinear multivariate predictive model of a batch fermentation process in accordance with an end of batch objective specifying a target end of batch biofuel concentration to determine an optimal batch trajectory over a temporal control horizon specifying a biofuel and/or sugar concentration trajectory over the batch fermentation process. A nonlinear control model for the batch fermentation process that includes the temporal control horizon driven by biofuel concentration during the batch fermentation process is executed per the determined optimal batch trajectory using received process information as input, thereby generating model output including target values for manipulated variables for the batch fermentation process, including batch fermentation temperature. The batch fermentation process is controlled per the target values to produce biofuel in accordance with the determined optimal batch trajectory, to substantially optimize the end of batch biofuel yield.

A controller for use with a power converter including a switch configured to conduct to provide a regulated output characteristic at an output of the power converter, and method of operating the same. In one embodiment, the controller includes a linear control circuit, coupled to the output, configured to provide a first control signal for the switch as a function of the output characteristic. The controller also includes a nonlinear control circuit, coupled to the output, configured to provide a second control signal for the switch as a function of the output characteristic. The controller is configured to select one of the first and second control signals for the switch in response to a change in an operating condition of the power converter.

A nonlinear PWM controller for switching power supplies

A circuit and method for controlling a switching regulator utilize a combination of variable off-time control (or frequency control) and variable peak current control to achieve high efficiency at a wide range of load conditions. A non-linear control circuit receives an error voltage and generates a first control signal for controlling a frequency control circuit and a second control signal for controlling a peak current control circuit. The frequency control circuit and the peak current control circuit operate in conjunction over the entire range of load conditions with the frequency control dominates at light load (or low power) conditions and the variable peak current control dominates at moderate to heavy load (or high power) conditions. The switching regulator transitions smoothly between frequency control and peak current control with continous loop gain throughout the transition region.

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.

A voltage regulator may be configured to detect variation in load current and control transient response when the load current has a high slew rate or varies at high repetition rates. A linear control circuit may be employed to control charging of an output capacitor and a load of the regulator. Upon detection of high load current step-up change at high slew rates, a non-linear control circuit may be activated. The fast load current step change may be detected by comparing an output voltage of the regulator to a feedback input of an error amplifier of the linear control circuit. The output of the error amplifier may be clamped to prevent output voltage ring-back when using the non-linear control circuit or to control load release dip. Output voltage overshoot may be controlled by turning OFF a top switch that charges the output capacitor before the inductor current becomes zero.

The invention discloses a method for controlling a four-switch buck-boost DC-DC converter. The method integrates the advantages of the linear control and the nonlinear control, adopts the control of a current mode during the steady state and carries out the voltage sampling at a voltage output terminal; the sampling voltage and the benchmark voltage are input in an error amplifier; the output signal of the error amplifier is used as the benchmark input of a current comparator; the output terminal of the error amplifier is also connected with a compensation network which consists of resistances and capacitors; when the loaded jumps, the nonlinear control is carried out. The invention also discloses a device used for implementing the method. The invention realizes the application of the nonlinear control on the four-switch buck-boost topology, simultaneously solves the technical problem that the oscillation occurs when the load jumps during the nonlinear control process, thereby leading the output voltage to reach the stable value quickly, and improving the response speed of the buck-boost converter.

A control system using a genetic analyzer based on discrete constraints is described. In one embodiment, a genetic algorithm with step-coded chromosomes is used to develop a teaching signal that provides good control qualities for a controller with discrete constraints, such as, for example, a step-constrained controller. In one embodiment, the control system uses a fitness (performance) function that is based on the physical laws of minimum entropy. In one embodiment, the genetic analyzer is used in an off-line mode to develop a teaching signal for a fuzzy logic classifier system that develops a knowledge base. The teaching signal can be approximated online by a fuzzy controller that operates using knowledge from the knowledge base. The control system can be used to control complex plants described by nonlinear, unstable, dissipative models. In one embodiment, the step-constrained control system is configured to control stepping motors.

The present invention provides a method for controlling nonlinear control problems within particle accelerators. This method involves first utilizing software tools to identify variable inputs and controlled variables associated with the particle accelerator, wherein at least one variable input parameter is a controlled variable. This software tool is further operable to determine relationships between the variable inputs and controlled variables. A control system that provides variable inputs to and acts on controller outputs from the software tools tunes one or more manipulated variables to achieve a desired controlled variable, which in the case of a particle accelerator may be realized as a more efficient collision.

The invention discloses an iterative learning trajectory tracking control and robust optimization method for a two-dimensional motion mobile robot. The method includes the steps that firstly, a kinetic equation of a two-dimensional motion mobile robot discrete non-linear motion system model is established; a discrete non-linear state space expression is established; a P type open-closed loop iterative learning controller based on the iterative learning control technology is established; then the robust convergence of the established discrete non-linear control system is theoretically analyzed; then parameter item splitting is conducted on control gains of the P type controller, meanwhile, a quadratic performance index function based on controller parameters is designed, and the purpose is to optimize the control parameters; finally, monotone convergence characteristics of output errors and parameter selection conditions generated when a control algorithm acts on a controlled system are analyzed and optimized, and the two-dimensional motion mobile robot can rapidly track an expected motion trajectory at high precision. The method has the advantages that the robust optimization iterative learning controller is suitable for tracking control in an ideal state and suitable for trajectory tracking tasks under the condition that interference exists outside. A designed iterative algorithm is simple and efficient, introduction of a large number of additional parameter variables is not needed, and engineering realization is easy.

In one embodiment, the controller of these teachings includes a nonlinear controller component capable of providing an amplitude determining input signal to a control signal providing component, the control signal providing component providing output having a predetermined amplitude substantially over one time interval from a number of time intervals or output having a predetermined average amplitude substantially over one time interval from a number of time intervals, the amplitude determining input signal corresponding to at least one predetermined system state variable. The nonlinear controller component is operatively connected to receive as inputs at least one predetermined system state variable. A relationship between the amplitude determining input signal and at least one predetermined system state variable is obtained by a predetermined method.

The invention provides an under-actuated unmanned surface vehicle self-adaptive trajectory tracking control device and method. The device comprises a reference path generator, a state sensor, a differential converter, a parameter estimator, a virtual controller and a longitudinal thrust and bow steering torque controller. According to the unmanned surface vehicle actual position and course angle collected by the state sensor (2) and the reference position and reference course angle information generated by the reference path generator (1), the new state variable is obtained through the differential converter (5), the new state variable and the speed and angle speed information collected by a sensor (4) are transmitted to the parameter estimator (8) and the longitudinal thrust and bow steering torque controller (12), a control instruction is obtained through calculation to drive an execution mechanism, and the longitudinal thrust and bow steering torque of an unmanned surface vehicle are adjusted. According to the device and method, the unmanned surface vehicle can reach the specific position within specific time at specific speed. Due to the under-actuated unmanned surface vehicle, energy consumption and manufacturing cost of a system can be lowered, and the weight of the system is reduced.

A system for controlling a soft start for a switching converter includes a digital feedback control system for receiving an analog voltage signal representing the output of a switching converter, for digitally processing the analog voltage signal by comparing it to a corrected reference voltage to generate a voltage error signal and for generating drive signals to control the operation of the switching converter to provide a regulated output. A microcontroller providers a secondary feedback loop for generating the corrected reference voltage. The secondary feedback loop enabling the output voltage signal to vary linearly over time during a soft start.

The invention belongs to the field of autonomous flight control research of mini-type rotary wing type unmanned aerial vehicles and discloses a method for nonlinear control over an unmanned helicopter posture and a verification platform. An unmanned helicopter is rapidly, accurately and stably controlled. Dependence on prior knowledge of a model by a controller is low and in terms of the uncertainty, the robustness of the system is good. According to the technical scheme, the method for nonlinear control over the unmanned helicopter posture comprises the following steps that firstly, experimental modeling is conducted through a sweep frequency method and a following dynamic model is given; secondly, an unmanned helicopter system is identified; thirdly, the unmanned helicopter posture is controlled. The method is mainly used for controlling autonomous flight of the mini-type rotary wing type unmanned aerial vehicle.

Advanced combustion modes, such as PCCI, operate near the system stability limits. In PCCI, the combustion event begins without a direct combustion trigger in contrast to traditional spark-ignited gasoline engines and direct-injected diesel engines. The lack of a direct combustion trigger encourages the usage of model-based controls to provide robust control of the combustion phasing. The nonlinear relationships between the control inputs and the combustion system response often limit the effectiveness of traditional, non-model-based controllers. Accurate knowledge of the system states and inputs is helpful for implementation of an effective nonlinear controller. A nonlinear controller is developed and implemented to control the engine combustion timing during diesel PCCI operation by targeting desired values of the in-cylinder oxygen concentration, pressure, and temperature during early fuel injection.

A control system for reducing cargo pendulation. The control system calculates a correction factor and adds the correction factor for the operator input motions in addition to the motion of the platform in order to provide a reference position of the suspension point of the hoisting cable. The reference position is then provided to a tracking controller so that the crane can be forced to track the needed motions for reducing the cargo pendulation.

The invention discloses an automatic load-variable multi-variable control method for an air separation device. According to the method, a module 1, namely a gain scheduling module, a module 2, namely a dynamic multi-variable model prediction control module, and a module 3, namely a process real-time optimization module are involved. The method comprises the following steps that: the module 3 calculates the optimal steady state value of a process variable related to load change according to the load-variable requirement of the device and sends the optimal steady state value to the module 2; the module 1 determines a prediction model adopted by a controller of the module 2 at the moment according to the current value of a scheduling variable; and the module 2 gradually pushes the device to the optimal steady state working point which is calculated by the module 3 on the premise of ensuring product quality and not going against equipment constraints. By the method, the problems of mutual decoupling of energy and a material, nonlinear control and the like in the wide-range load-variable process of the air separation device can be radically solved, smooth and quick transition among different working conditions is realized, and the load-variable operation quality and speed of the air separation device are ensured.

The invention discloses a motor position servo system self-adaptive control method based on an interference observer. The motor position servo system self-adaptive control method based on an interference observer includes the steps: establishing a mathematical model for a motor position servo system; constructing an interference observer and a self-adaptive controller based on the interference observer; and by means of a Liapunov stability theory, performing stability demonstration on the motor position servo system, and obtaining a global asymptotic stability result of the system by operatinga Barbalat lemma. The motor position servo system self-adaptive control method based on an interference observer is based on an integration series model and the interference observer of the motor position servo system, designs a non-linear control method based on the interference observer, integrates the non-linear control method with self-adaptive control, respectively estimates unmodeled interference and parameter nondeterminacy to enable the servo system to achieve the effect of global asymptotic stability when unmodeled interference is time-varying interference for the servo system, and solves the strong parameter nondeterminacy problem and the strong nondeterminacy non-linear problem of the system so as to enable the system to obtain better tracking performance.

The invention relates to an auto disturbance rejection control technology-based direct-current busbar voltage control method of a high-voltage chain-type STATCOM (Static Synchronous Compensator) power unit module. Capacitors at the direct-current side of a chain-type STATCOM are mutually independent; the individual unit module has direct-current capacitor loss difference, switch loss difference, drive pulse delay time difference, and the like in the running process; the voltage of the direct-current capacitor of each chain-type STATCOM unit module is unbalanced and has difference, so that harmonic contents of an output voltage and an output current of the chain-type STATCOM unit module are influenced, even the normal and safe operation of the chain-type STATCOM unit module is endangered. According to the method disclosed by the invention, an auto disturbance rejection controller does not need to judge the instantaneous current direction; after parameters are accurately set, the disturbance quantity contains active components with active fluctuation; and the auto disturbance controller can achieve the purposes of high response speed and no overshoot of voltage of the unit direct-current capacitors due to the existence of a tracking differentiator and a nonlinear controller.