98 results about "Second order systems" patented technology

The invention relates to a hypersonic aerocraft tracking control method with an interference observer. The problem that the fact that the observer is bounded in the interference process of an observing system cannot be proved in the prior art is solved. The method provided by the invention comprises the steps that 1 a second-order system model with system interference is established according to the longitudinal input and output linearization model of a hypersonic aerocraft; 2 according to the second-order system model with system interference in the step 1, a finite time terminal sliding mode controller is designed based on a sliding mode control theory; and 3 system stability proving is carried out on the finite time terminal sliding mode controller designed in the Step 2. According to the method provided by the invention, the finite time of the sliding surface of the system is stable, and the system state is asymptotically convergent. The method provided by the invention is applied to the field of hypersonic aerocraft control.

The invention relates to a hypersonic aircraft robust tracking control method based on a terminal sliding mode, and solves the problems of complex control model, poor robustness and lack of consideration of controller input limitation of an existing aircraft. A hypersonic aircraft input/output linearization model is provided, and is converted into a second-order system model by introducing an error auxiliary variable; for the conditions that unknown upper bound exists in system interference and an actuator has no input saturation, an adaptive fast terminal sliding mode controller is designed based on a fast non-singular terminal sliding mode surface, thereby ensuring that the sliding mode surface is actually convergent in finite time; and by introducing a hyperbolic tangent function and astructural auxiliary system, an anti-saturation adaptive fast terminal sliding mode controller is designed, thereby meeting requirements of physical constraints of a hypersonic aircraft and meanwhile,ensuring that the system sliding mode surface is convergent in finite time. The method is applied to the aircraft field.

The invention discloses a sliding mode attitude control method for a quadrotor UAV based on a proportional integral observer. The method comprises steps that a dynamic model of the quadrotor UAV withinterference only is established, and expressions of a rolling angle, an elevation angle and a yaw angle of the quadrotor UAV are transformed into second-order system models; the second-order system models are utilized to construct the corresponding proportional integral observer; a sliding mode attitude controller is designed according to the proportional integral observer, and the sliding mode attitude controller in combination with the rolling angle, the elevation angle and the yaw angle is utilized for flight control of the quadrotor UAV. The method is advantaged in that the proportional integral observer is combined with the sliding mode attitude controller, the partial feedback function of the proportional integral observer is utilized to estimate the shape and position input interference state of the quadrotor UAV, steady state tracking accuracy of the proportional integral state observer is improved, through the sliding mode attitude controller, relatively strong robustness andanti-interference to uncertain factors of the quadrotor UAV are achieved, and design and calculation are simple.

The invention relates to a crane anti-swinging control method based on a positive and negative POSICAST input reshaping method, which is applicable to any n time lag conditions. When the time lag of a designed reshaping device is shorter, the maximum value of a swinging angle is larger; when the time lag is longer, the maximum value of the swinging angle is smaller; meanwhile, when the jumping of an accelerated velocity is smaller, and the speed is gentler. A user can select freely according to actual conditions. The crane anti-swinging control method disclosed by the invention is applicable to a damping system and is also applicable to a non-damping second-order system. The method is an open loop control method, so that the method has the advantages that a measurement sensor for closed loop feedback is not needed. The crane anti-swinging control method utilizes phase step accelerated velocity input and aims at reshaping of phase step accelerated velocity output; compared with a pulse accelerated velocity input method, the speed is continuously changed, and a project is easy to realize. The crane anti-swinging control method is suitable for taking any phase step signal as input, and a damping second-order system is used for an anti-swinging system or a system for enabling certain output to finally return back to an original position.

The invention discloses a group consistency control method for a heterogeneous multi-agent system with arbitrary bounded time delay, and the method comprises the following steps of constructing mathematical models of a first-order system and a second-order system, determining a topology of the multi-agent system, and describing its topological relationship by using graph theory knowledge; designing a control protocol of heterogeneous multi-agent system with time delay; analyzing the consistency problem of the system by using the properties of matrix theory and non-negative matrix to obtain a system convergence condition; determining a control protocol scaling parameter that meets the system convergence condition, and substituting the parameter into the system control protocol to implementthe group consistency control of the system. The invention provides the group consistency control method for the heterogeneous multi-agent system with arbitrary bounded time delay, and the method solves the global control problem by a distributed control method with no need of global information of the system, and only requires joint connection of topological graphs of the system at the same timewithout requiring their sub-graphs to be connected, thereby improving the robustness of the system and being suitable for group consistency control of heterogeneous multi-agent systems with arbitrarybounded delays.

The invention discloses a five-DOF (freedom of degree) bearingless synchronous reluctance motor decoupling controller and a construction method thereof. Three expanded current hysteresis loop PWM (pulse width modulation) inverters, a switch power amplifier and a five-DOF bearingless synchronous reluctance motor form a compound controlled object; five support vector machine second-order systems, one support vector machine first-order system and eleven integrators are utilized to construct a support vector machine alpha-order inverse system and offline training is carried out, the support vector machine alpha-order inverse system is placed in front of the compound controlled object to form a pseudo linear system, and the pseudo linear system is equivalent to five position second-order integration subsystems and one position first-order integration subsystem; and five position controllers and one rotating speed controller are respectively designed for the six integration subsystems, thus a linear closed-loop controller is formed. In the invention, a least square support vector machine is adopted to approach an alpha-order inverse model of a nonlinear system, the dynamic decoupling control among all the controlled variables is realized, and the control performance of the overall system is effectively improved.

The invention relates to a positive and negative POSICAST input shaping method-based crane anti-swing control method. The method includes a positive and negative POSICAST method adopted when a swing angle returns to zero after a time point 3Td/2, a positive and negative POSICAST method adopted when the swing angle returns to zero after a time point Td, and a positive and negative POSICAST method adopted when the swing angle returns to zero after a time point 3Td/4, wherein Td is the damped oscillation period of a system. The method of the invention is either applicable to a damped system or an un-damped two-order system. The method of the invention is an open-loop control method. With the method adopted, a measuring sensor for closed-loop feedback is not required. According to the method of the invention, step acceleration input is utilized, and the shaping of step acceleration output is targeted. Compared with a pulse acceleration input method, the method has the advantages of continuous speed change and easiness in engineering realization. The method of the invention is applicable to any damped two-order systems adopting step signals as input, and is used for an anti-swing system or a system of which the output of a certain item is expected to return to an original position.

The invention discloses a digitization sampling time delay frequency conversion measuring method, and the method measures the non integer period time delay to the different frequency steady state analog quantity signals from an electronic transformer or analog inputting and merging unit to obtain the inertial time delay to all frequency signals from the digitization sampling process, including the non integer period time delay and integer period time delay, compensates the sending time difference for SV message based on the transmit frequency of the phaselock technique tracking SV message, reduces the influence caused by the sending time difference for SV message, and raises the digitization sampling time delay measuring precision. The invention also discloses a test system based on the method for ensuring the reliable application of the electronic transformer and the analog inputting and merging unit in the intelligent substation, eliminating the potential safety hazard of the electronic transformer and the analog inputting and merging unit on engineering application, raising the second-order system running veracity for the intelligent substation and having significance to the safe and reliable operation for the intelligent substation.

The invention discloses a rapid three-phase voltage phase-locked loop method and a dynamic response performance analyzing method thereof, and belongs to the technical field of electric power and electronic control. The analyzing method comprises the following steps: establishing a simplified model of a phase-locked loop, obtaining an open-loop transfer function of a traditional three-phase voltage phase-locked loop and a high-speed three-phase voltage phase-locked loop based on the simplified model, and obtaining a root locus of the changes of a PI regulator parameter Kp based on the open-loop transfer function, a sampling frequency and a fundamental wave angular frequency; drawing two root loci in the same coordinate system, performing equivalent simplification on a high-order system to a typical second order system through the method of closed loop dominant apices, and obtaining convergence time t1 and t2 of the typical second order system in correspondence to the traditional three-phase voltage phase-closed loop and the high-speed three phase voltage phase-locked loop. The analyzing method begins with a simplified mathematics model from a rapid three-phase voltage phase-closed loop structure, conducts separate and detailed discussion on time domain and frequency domain mathematics models, and at the same time demonstrates a theory analysis based on a relevant simulation platform and a hardware experiment platform.

The invention discloses a novel active-disturbance-rejection controller with an embedded model. The novel active-disturbance-rejection controller comprises an extended state observer module arranged in the inner ring and a proportional differential feedback module arranged in the outer ring; model information is embedded in the extended state observer module and used for observing the total disturbance of a system outside a nominal model, and then transforming a controlled object into a series integrator standard type by compensating the part of the total disturbance and known dynamics in realtime in the inner ring; the proportional differential feedback module is based on the series integrator standard type and adjusts he output control amount through parameter setting according to a quantitative relationship between an outer ring controller differential parameter kd and a second-order system damping coefficient zeta to achieve the control of the controlled object; the system is thesystem of the controlled object. The novel active-disturbance-rejection controller with the embedded model can reduce the burden of an extended state observer, achieves the purposes of more accurate disturbance estimation and set value tracking and reduction of the influence of noise on the output control amount, and provides convenience for parameter setting and adjustment in an actual control process.

A RLV landing section guidance law acquiring method based on a sliding-mode control theory comprises steps of: calculating a height deviation and a lateral distance deviation according to an RLV landing section nominal trajectory; then, selecting an appropriate sliding-mode surface according to the tracking deviation of the nominal trajectory, and equivalently converting a RLV three-degree-of-freedom kinetic equation into a form described by the sliding-mode surface; and finally, designing the guidance law by using a Lyapunov method. In the design process, by analyzing aerodynamic data, the uncertainty upper bound of a guidance circuit is obtained and a compensation term is introduced to suppress the uncertainty so that the guidance system has asymptotic stability to the uncertainties such as disturbance. The method can overcome the influence of the uncertainty of the RLV guidance system so as to improve guidance precision, converts an original second-order system into a first-order system by introducing the sliding-mode control method, thereby achieving a visual design process.

A second-order sliding mode control method for magnetically suspended switched reluctance motor is disclosed in the invention. The speed loop adopts the second-order sliding mode speed controller based on the superscrew algorithm, The reference torque is obtained by selecting the speed error to construct the sliding mode surface and combining with the mechanical equation of the maglev switched reluctance motor. The displacement loop adopts the second-order sliding mode displacement controller based on the improved superscrew algorithm, A high order error derivative of displacement is introduced to make the superhelix algorithm suitable for second order systems, The reference levitation force is obtained by improving the superscrew algorithm combined with linear compensation term. The invention adopts a second-order sliding mode speed controller based on a superscrew algorithm and a second-order sliding mode displacement controller based on an improved superscrew algorithm, The speed control precision and rotor suspension precision of SRM are improved, the problems of speed buffeting and displacement buffeting are solved, and the system has strong robustness to uncertain disturbance, which is easy to be realized in engineering.

The invention discloses a control design method of a hypersonic flight vehicle. The method comprises the following steps that a longitudinal model of the hypersonic flight vehicle is given; finite time height control design to the hypersonic flight vehicle is achieved according to an engine dynamic equation described by a second-order system model; according to the sufficient condition of controller gain selecting, a flight speed and a flight path angle are converged to a given value within the finite time, and therefore the finite time speed control design to the hypersonic flight vehicle is achieved. According to the motion control design method of the hypersonic flight vehicle, based on the control method of a finite time control technology, the controller design method of dynamic inverse and the finite time control technology is combined, height control and speed control are seen as two sub systems for designing controllers respectively, and the difficult problems that the model order of the hypersonic flight vehicle is high and finite time control can not be achieved easily are solved.

The present invention adds gain and phase into a canonical second order system in order to mitigate the adverse effects of unwanted resonance, where the gain is added to the forward path of a control loop of the system and is a ratio of the square of the system and mechanism frequencies, and the phase lead (H-factor) is added to the feedback path of the control loop of the system and is a complex ratio of these frequencies which includes a dc-component (H_dc) and a zero- or pole-component. By adding gain and phase lead, which is contrary to current approaches to addressing resonance, the present invention achieves the desired result of resonant free application in a canonical resonant-prone system of second order, and the methodology is applicable to higher order systems.

The invention discloses a virtual automatic control experimental system and a design method of the virtual automatic control experimental system. The virtual automatic control experimental system comprises a time domain analysis method experiment module, a root-locus method experiment module, a frequency domain analysis method experiment module, a system correction experiment module and an open experiment module, wherein the time domain analysis method experiment module comprises a first-order system time domain analysis module, a second-order system time domain analysis module and a high-order system time domain analysis module; the root-locus method experiment module comprises a second-order system root-locus analysis module, a third-order system root-locus analysis module and a high-order system root-locus analysis module; the frequency domain analysis method experiment module comprises a typical link frequency response characteristic analysis module and a composite system frequency response analysis module; the system correction experiment module comprises a series connection lead correction module, a series connection lag correction module, a series connection lag-lead correction module and a PID correction module; the open experiment module comprises a water level control module, an elevator control module and a traffic lamp control module. By means of the virtual automatic control experimental system and the design method, a user can design and simulate an automatic control experiment, the efficiency of the automatic control experiment is improved, limitation of hardware equipment is avoided, an experimenter can conveniently have a study, and shortcomings in a traditional experiment are overcome.

The invention discloses a robust adaptive control method for a piezoelectric ceramic driving component in a variable load environment; the method comprises the following steps as follows: establishinga piezoelectric ceramic driving system, setting a driven component to be a rigid load loaded in a vertical direction of the piezoelectric ceramic driving component, and measuring the output displacement by a laser displacement sensor, wherein the output displacement of the rigid load is consistent with the output displacement of the piezoelectric ceramic driving component; performing mathematicalmodel description on the variable-load piezoelectric ceramic driving component; and designing a robust adaptive controller. The robust adaptive control method considers uncertainties in the system and environmental disturbances, based on the mathematical model of the piezoelectric ceramic driving system in a loaded environment, a measurable-output second-order system with a hysteresis characteristic is used, a specified performance function is set to control system errors so as to achieve real-time adjustment of the robust adaptive controller output, so that high precision tracking driving accuracy of the piezoelectric ceramic driving platform to the input signal is ensured.

Accuracy of correction of offset drift with temperature and noise are corrected in a high voltage, high current amplifier is improved by thermal isolation and/or temperature regulation of another amplifier having greater gain and connected to a different power supply in a closed loop feedback servo system. A clamping network connected to the higher gain amplifier to avoid hard saturation due to transient feedback signals from a reactive load, especially an inductive load, also prevents hard saturation of the high voltage, high current amplifier. An adjustable feedback circuit connected to the higher gain amplifier allows adjustment to obtain critical damping of a second order system and faster response to achieve proportionality of output current to input voltage with an accuracy of very few parts per million error and with minimum settling time.

A model-free predictive current control method based on an extended state observer is provided. The method comprises: writing a state equation of a second-order system, using a linear extended state observer and constructing a linear state observer equation; by combining a super-local model of current control of an asynchronous motor oriented based on the indirect magnetic field, designing a stator current linear extended state observer; discretizing the observer and choosing appropriate observation parameters to ensure the stability and good control performance of the observer; and writing the designed stator current linear extended state observer as the state equation to obtain an observation error of the observer, and obtaining a characteristic equation of the extended state observer soas to set reasonable observation parameters. According to the model-free predictive current control method based on an extended state observer provided by the present invention, current control without any motor parameter is realized, and the robustness of the model predictive control (MPC) to the motor parameters is greatly improved.

The invention discloses a method and device for detecting ice thickness. The method comprises the following steps that a sensor is equivalent to an underdamped second-order system; only when it is required to detect the state information of the ice thickness, a pulse excitation signal is input to the sensor to detect and analyze an output response signal of the sensor system to the pulse input excitation signal; since the ice thickness of the surface of the sensor will change the basic parameters of the second-order system to varying degrees, a plurality of characteristics of the output response signal of the sensor system will change accordingly, and the information of the ice thickness can be obtained by detecting and analyzing the changes of these characteristics; and by applying the input pulse excitation signal to the sensor system, several different modes of operation can be selected. The method and device for detecting ice thickness can greatly prolong the working life of the sensor, realize accurate and reliable detection of the icing thickness by detecting various characteristics of the output response signal of the sensor, and have a plurality of different modes of operation available for selection such that the application of the sensor is more flexible and convenient.

The invention discloses a teaching experiment system for the automatic control principle, and belongs to the field of teaching experiment system designing. The teaching experiment system comprises a mechanical loading device, a lower computer, two displacement sensors and an upper computer. The lower computer comprises a CPU and an A/D conversion module, wherein the upper computer, the CPU, the mechanical loading device, the two displacement sensors and the A/D conversion module are connected in sequence; the two displacement sensors and the CPU are respectively connected with the A/D conversion module. According to the teaching experiment system, as a mechanical device is adopted to form a typical second-order system serving as a controlled object, the operation state of an actual system under different controlled conditions can be observed by students, and intuitional instruction and theory and practice combination are facilitated. Besides, the teaching experiment system has important significance for improving laboratory teaching quality and strengthening understanding of the control theory and control engineering for the students.

The invention relates to an order reducing method of a higher-order mathematical model for a water turbine regulating system. The order reducing method comprises the following steps: a. simplifying the highest-order term of a system denominator, and achieving primary order reduction of the system to obtain a primary lower-order equivalent system formula; b. from the angle of fluctuation superposition, transforming the primary lower-order equivalent system formula into a form that two second-order subsystems are added; c. performing an Laplace inverse transform to obtain a unit rotating speed response wave equation of the primary lower-order equivalent system of the water turbine regulating system under load step disturbance; d. performing secondary order reduction on a complete fifth-order system formula; e. performing influence factor analysis of rotating speed response regulating quality of the water turbine regulating system by using a second-order system. The order reducing method has the advantages that compared with other order reducing methods, by the method, starting from the complete fifth-order system, all parameters and influence factors of the system are contained, and the later regulating quality analysis with reliable guarantee is provided.

The invention discloses a multi-agent system consistency achieving method based on cell decomposition, and belongs to the technical field of multi-agent systems. By means of the multi-agent system consistency achieving method based on cell decomposition, the multi-agent system consistency convergence speed is increased, the problem that a consistency convergence speed increasing method is difficult to implement in actual application is solved, and the problem of a single-layer topology is converted to the problem on a multi-layer topology to be solved on the premise of neither changing a multi-agent topology relation nor changing connecting weight. Meanwhile, the method has the good improvement effect on a first-order system and a second-order system. The multi-agent system consistency achieving method is applied in wide-range engineering application based on a ground unmanned trolley system, an unmanned aerial vehicle system, a self-organization underwater fleet, a satellite group and the like, and has the practical significant in better application.