605 results about "Attitude control system" patented technology

The invention discloses a nonlinear output feedback flight control method for a quad-rotor unmanned aerial vehicle. The nonlinear output feedback flight control method for the quad-rotor unmanned aerial vehicle comprises the following steps of: (1) determining a kinematic model of the quad-rotor unmanned aerial vehicle under an inertial coordinate system and a kinematic model of the quad-rotor unmanned aerial vehicle under a body coordinate system; (2) designing an attitude control system of the quad-rotor unmanned aerial vehicle; defining tracking errors of the attitude angle and the angular speed of the quad-rotor unmanned aerial vehicle; designing a filter to perform online estimation on an angular speed signal and obtain an open loop dynamic equation of the tracking errors; and estimating unknown functions in the open loop dynamic equation by adopting neural network feedforward, and designing attitude system control output of the quad-rotor unmanned aerial vehicle; and (3) designing a height control subsystem of the quad-rotor unmanned aerial vehicle; defining height tracking errors and defining auxiliary filtering tracking errors; and designing a height subsystem controller. According to the nonlinear output feedback flight control method for the quad-rotor unmanned aerial vehicle disclosed by the invention, the polarity problem is effectively avoided, a wide-range stable control effect is achieved, the robust performance of the system is greatly improved, and the dependence of a flight controller on an airborne sensor is greatly reduced.

The invention discloses an attitude control system for space vehicle and a method thereof. The control system has only one biased momentum wheel, one set of tri-axial magnetic torquer and one attitude controller loaded with algorithm. The method comprises a step of rate damping controlling, a step of initially capturing controlling and a step of stationarity controlling. At the rate damping stage, geomagnetism change is used to control the magnetic control of three passages of a satellite by B-dot; at the initially capturing stage, the magnetic control is realized, PD control is performed by pitching and the passages are rolled and yawed to carry out nutation and precession composite control; at the stationarity controlling stage, the magnetic control is realized, PD control is performed by pitching and the passages are rolled and yawed to carry out nutation and precession composite control. The capturing stage and the stationarity controlling stage fully depend on magnetic torquer to perform positive magnetic control, thereby changing which a satellite only uses a magnetic torquer to carry out unload of the momentum wheel or auxiliary magnetic control, so as to refine system configuration to further improve reliability of the system. Momentum of a satellite is biased to rotate on the ground, so as to ensure stable separation of the satellite without performing air injection control. Therefore, the magnetic torquer can be used for realizing fast and stable initial rate damping.

The invention relates to a spacecraft attitude integral sliding mode fault tolerance control method taking consideration of a performer fault and provides a robustness attitude active fault tolerance control method based on an integral sliding mode surface for problems of the performer fault, external disturbance and control moment amplitude limits in a spacecraft attitude control process. The method comprises steps that firstly, a spacecraft attitude dynamics model taking consideration of the performer fault and containing external disturbance is established; secondly, on the condition that a performer is not in fault, a designed nominal controller can guarantee system stability, and input saturation amplitude limits can be easily satisfied through adjusting controller parameters; lastly, the fault information is introduced to design an integral sliding mode controller, robustness of external disturbance and the performer fault can be effectively improved, system stability is analyzed on the basis of an Lyapunov method. The method is advantaged in that stability of the attitude control system is guaranteed when a spacecraft operating on orbit generates the performer fault, and relatively strong fault tolerance capability and external disturbance robustness are realized.

A posture control system for a mobile robot. When an unexpected external force acts, the system is configured to control and stabilize the posture of the robot driving an arm link such that, in response to a first external force that is a component in a predetermined direction of an unexpected external force, a second external force acts on the arm link in a direction orthogonal to the predetermined direction. With this, when the mobile robot receives a reaction force, even if the posture becomes unstable or the robot receives an unexpected reaction force, it becomes possible to preserve the dynamic balance and to maintain a stable posture.

Provided is a sliding-mode control method with anti-interference fault-tolerance performance. A sliding-mode controller with anti-interference fault-tolerance performance is designed and is specific to a system containing faults and interferences. Firstly, faults and multi-source interferences in the system are considered, so that a dynamical model of the system is established. Secondly, a fault diagnosis observer and a disturbance observer are designed to estimate the faults and interferences capable of being modeled. Thirdly, the gain matrix of the disturbance observer and the fault diagnosis observer is solved. Then, the sliding-mode controller is designed to offset faults and interferences respectively by using the estimated value of faults and interferences. Finally, stability of the controller is analyzed and the sliding-mode yield value is determined on the premise that the system input is saturated. According to the sliding-mode control method with anti-interference fault-tolerance performance, the anti-interference and fault-tolerance performance of the system are guaranteed, the buffeting of the sliding-mode control is improved, and the sliding-mode control method can be applied to the attitude control system of the fields of aviation, aerospace and deep space exploration.

Various embodiments of the present invention include an attitude control system for use with small satellites. According to various embodiments, the system allows rapid retargeting (e.g., high slew rates) and full three-axis attitude control of small satellites using a compact actuation system. In certain embodiments, the compact actuation system includes a plurality of single-gimbaled control moment gyroscopes (SGCMG) arranged in a pyramidal configuration that are disposed within a small satellite.

The invention relates to a quadrotor unmanned aerial vehicle attitude control system modeling and finite time attitude tracking control method, in particular to a quadrotor unmanned aerial vehicle finite time attitude tracking control method. Disturbance torque with which a quadrotor unmanned aerial vehicle is confronted is comprehensively analyzed, rotating inertia is unknown, output saturation and actuator failure and other factors are controlled, a passive fault-tolerant controller is designed on the basis of a parameter adaptive method, and the finite time stabilizing function is achieved. The method comprises the steps of 1 building a quadrotor unmanned aerial vehicle attitude tracking kinematic model, 2 building a quadrotor unmanned aerial vehicle attitude tracking kinetic model, 3 defining quadrotor unmanned aerial vehicle attitude smoothing errors, 4 designing a finite time integral sliding mode surface, and 5 designing a quadrotor unmanned aerial vehicle finite time attitude tracking controller. The method is used for the field of unmanned aerial vehicle flight control.

The invention discloses a reentry aircraft finite time control method based on a disturbance observer and relates to the reentry aircraft finite time control method. The reentry aircraft finite time control method belongs to the field of aircraft control technology. The reentry aircraft finite time control method comprises the following steps: a first step, establishing a reentry aircraft dynamic model, presenting a finite time gesture tracking task; a second step, performing feedback linear processing on a model which is established in the first step; a third step, providing a finite time control law; a fourth step, providing a finite time disturbance observer for estimating system uncertainty and outer disturbance; and a fifth step, providing a finite time global sliding mode control method based on the disturbance observer, and effectively improving tracking precision of a gesture control system through substituting an estimated disturbance value into the control law. The reentry aircraft finite time control method has functions of improving system error convergence speed, preventing a singular problem and improving uncertainty of the controlled system to the parameter, global robustness of outer disturbance and tracking precision.

A missile includes a payload assembly that has a pair of nosecones. The nosecones may be optimized for different environments and / or phases of flight, for example, having different shapes, different shell materials, different types of seals, and / or different separation mechanisms. The first (outer) nosecone may have a more streamlined shape, be made of more thermally-protective material, and may meet less stringent sealing requirements, than the second (inner) nosecone. Separation of the outer nosecone from the payload assembly may cause backward movement of a center of pressure of the payload assembly, bringing the center of pressure of the assembly closer to a center of gravity of the assembly. This may make the payload assembly easier to maneuver, for example, reducing or eliminating the need for intervention by an attitude control system, to maintain the payload assembly on a desired course.

The invention discloses a dual-redundancy attitude control system of a coaxial unmanned helicopter, which consists of a serial communication module, a PCM (Pulse-Code Modulation) decoding module, an AD acquisition module, a PWM (Pulse-Width Modulation) output module and a CPU control module. The serial communication module, the PCM decoding module and the AD acquisition module are used as system input, the CUP control module carries out improved digital PID control, and the PWM output module carries out output in the form of PWM pulses, and thus, the control of a backward-stage high power valve is realized. A debug method comprises the following fives steps of: firstly, connecting a defined I / O port to a high or low-level end according to a parameter debug object; secondly, adjusting a potentiometer to provide initial parameters for Kp and Kd and controlling the backward-stage high power valve; thirdly, keeping a neutral position of Futaba unchangeable, adjusting the potentiometer so that a steering engine achieves a critical state of self-excitation vibration; fourthly, operating the Futaba to output a signal exceeding a pulse threshold; and fifthly, operating the Futaba to return to a central position. The method realizes the debug and the storage of relevant parameters, decreases interference and improves the system stability and the response speed.

The invention relates to a tail angle restraining guidance method based on sliding mode control, and belongs to the technical field of guidance. Firstly, a novel aircraft kinematics and dynamics model is built, then tail time is guided, distance between aircraft position coordinates and target position coordinates (xf, yf) is minimum, an expected tail end trajectory dip angle gamma f is a designed target, according to a back stepping method, a virtual control volume is designed to enable a sliding mode function and a differential coefficient to be simultaneously up to 0 in the tail time of flying, and according to Lyapunov method, trajectory dip angle change rate gamma' of an auxiliary control volume is obtained in a solving mode. The trajectory dip angle change rate is converted into an attack angle alpha, an aircraft novel model which is initially built is inputted, a track of the aircraft is adjusted in a real-time mode so as to meet an expected terminal condition, and therefore tail guidance is achieved. The method considers effect of aerodynamic characteristics of the aircraft on a guidance process, is more close to an actual condition, needs little information volume, and is wide in obtained trajectory dip angle tail value range, and smooth in obtained control volume change, and an attitude control system is easy to track.

The invention discloses an inner system for controlling the gestures of an underwater robot, comprising a main controller connected with an adjustment mechanism, a gesture sensor, and an upper computer controller, wherein the adjustment mechanism is a balance adjustment mechanism arranged inside the underwater robot, and comprises a gravity slider, a double-shaft drive motor, a worm, a guiderail, a slide bar, a limit switch and a mechanism platform; the double-shaft drive motor is connected with the worm to drive the worm to rotate bidirectionally; the worm drives the slide bar to perform planar movement through the transmission of a lead screw; one end of the slide bar is connected with the lead screw of the worm and penetrates the gravity slider, while the other end thereof is connected with the guiderail by a slider and drives the gravity slider to move in a plane so as to realize the gravity adjustment of the underwater robot and control the transverse swing and longitudinal incline gestures of the underwater robot. The control system for gestures can be widely applied to the gesture control of the underwater robot.

The invention discloses a near spacecraft fault diagnosis and fault-tolerant control method. Firstly, a dynamical model of an attitude control system of a reentry phase of a near spacecraft is established and the dynamical model of the attitude control system is transferred to a nonlinear equation in a general type through coordinate transformation; secondly, a fault model with actuator invalidation and actuator dynamic damage existing simultaneously is established; thirdly, real-time online estimation of self-adaption estimation observer to actuator dynamic damage factors and actuator invalidation factors is respectively established; and finally a sliding module fault-tolerant controller is designed through the estimated actuator dynamic damage factors and the estimated actuator invalidation factors and parameters of the controller is updated in real time. According to the near spacecraft fault diagnosis and fault-tolerant control method, in the condition that when the actuator dynamic damage and the actuator invalidation occur simultaneously in a flight control system, fault information can be estimated rapidly and accurately, strong fault-tolerant capacity is achieved and an expected requirement of the flight control system is reached.

The invention relates to a steering-law singularity avoiding aircraft attitude control system, comprising an attitude task managing unit, an attitude controller, an attitude measuring unit, a gyro group steering-law unit, a frame angle position measuring unit, a control moment gyro group and an aircraft. The gyro group steering-law unit calculates the frame angle rate of the control moment gyro group by cooperating control moment gyro angle momentum table, zero motion algorithm and pseudoinverse steering-law algorithm, and adopts the angle rate value as the set signal of the control moment gyro group to improve the control precision of the aircraft attitude. The steering-law singularity avoiding aircraft attitude control system introduces the steering-law design method that chooses frame angle rate and the initial value of frame angle position based on look-up table, realizes accurate moment output of the control moment gyro group, avoids the singularity problem produced in the process of calculating frame angle rate of the control moment gyro group by the pseudoinverse steering-law algorithm as well as avoids the deadlock problem caused by the control moment gyro steering law when adopting zero motion algorithm and robust pseudoinverse steering-law iterative computations.

The invention discloses an attitude control system and a control method of a four-rotor aircraft. Firstly, the information of attitude angles of the current aircraft is obtained, and the attitude angles include a roll angle, a pitch angle and a yaw angle; secondly, controllers for the roll angle, the pitch angle and the yaw angle are respectively designed, wherein the controller for the roll angle is the same as that for the pitch angle; and finally, after obtained control inputs of the three controllers are overlapped, a total driving signal is output, thereby driving a motor to operate, so as to control the attitude of the aircraft. A gyroscope and an accelerometer are combined, and a Kalman filter is designed in accordance with models of the attitude angles of the aircraft, so as to conjecture the attitude angles on line. Additionally, variables of the intermediate state of the system can be obtained, and a certain filtering effect is achieved.

The invention relates to a satellite active fault-tolerant control method based on an observer and online control allocation. The active fault-tolerant control method based on the iterative learning observer is provided for the problems of actuator faults, limited input saturation and external disturbance in the satellite attitude control process. The method comprises the following steps that a satellite attitude control system model is established by considering the actuator faults and the external disturbance subjected by a satellite; the iterative learning observer is designed, and invalidation factors of an actuator are estimated; a virtual feedback controller is constructed based on fault estimation information, online control allocation is conducted simultaneously, and therefore precise estimation of the actuator faults and controller reconstruction can be conducted through the satellite. According to the method, the stability of the attitude control system is guaranteed when an on-orbit working satellite is subjected to actuator faults, and the method has the advantages that the control accuracy is high, and the fault-tolerant capability and robustness to the external disturbance are high.

Based on a neural network technology and an instruction filtering inversion method, the invention discloses a robust fault tolerance control system design structure based on instruction filtering inversion. Firstly, a mathematical model of an NSV attitude control system is given out, uncertainties and external disturbance caused by modeling errors are considered based on the mathematical model, a state equation of the NSV attitude control system under the fault of a control surface is also considered. The method mainly includes the two design parts including design of an auxiliary system and design of a controller based on the auxiliary system. The auxiliary system is introduced into the neural network to ensure robustness of the auxiliary system, and stability of a closed-loop system is strictly proved through Lyapunov theorem. Meanwhile, simulation is carried out on an attitude control system of a corresponding air vehicle, and a result shows that the method enables the uncertain flight control system with the external disturbance to have the ideal fault tolerance tracking performance under damage to the control surface.

Provided are a fault detector and a fault detection method for an attitude control system (ACS) of a spacecraft. The fault detector includes a first interacting multiple model (IMM) fault detection block for generating a normal model filter of the plurality of actuators and a plurality of upper level filters including fault model filters corresponding to the respective actuators, and detecting faults of the plurality of actuators using an IMM estimation technique from the plurality of upper level filters, and a second IMM fault detection block for generating a plurality of lower level filters each including a fault type model filter of the fault-detected actuator in the first IMM fault detection block, and detecting a fault type of the failed actuator using the IMM estimation technique.

The present system and methods enable simultaneous momentum dumping and orbit control of a spacecraft, such as a geostationary satellite. Control equations according to the present system and methods generate accurate station-keeping commands quickly and efficiently, reducing the number of maneuvers needed to maintain station and allowing station -keeping maneuvers to be performed with a single burn. Additional benefits include increased efficiency in propellant usage, and extension of the satellite's lifespan. The present system and methods also enable tighter orbit control, reduction in transients and number of station-keeping thrusters aboard the satellite. The present methods also eliminate the need for the thrusters to point through the center of mass of the satellite, which in turn reduces the need for dedicated station-keeping thrusters. The present methods also facilitate completely autonomous orbit control and control using Attitude Control Systems (ACS).

The invention relates to a spacecraft fault tolerant control method based on an angular speed observer. The method comprises a step of considering an actuator fault and external disturbance borne by a spacecraft, and establishing a spacecraft attitude control system dynamics and kinematics model, a step of designing a finite time observer to estimate the attitude angular velocity information of a spacecraft, and a step of constructing a robust controller based on the obtained angular velocity information, and at the same time considering control amount input saturation and designing an auxiliary system such that the spacecraft has robustness for the actuator fault without angular velocity information. According to the method, the stability of an attitude control system is ensured when an on-orbit working spacecraft has the actuator fault and even the attitude angular velocity information is unknown, and the method has high control precision, high fault tolerance ability and robustness to external disturbance.

The invention relates to a flexible spacecraft attitude control system and a flexible spacecraft attitude control method in allusion to flywheel low-speed friction. The system comprises six modules which are a flexible spacecraft dynamics real-time simulation module with actuating mechanism characteristics, a flexible spacecraft kinematics real-time simulation module, an attitude measurement module, an attitude determination module, an attitude control module and an executing mechanism module, wherein the flexible spacecraft dynamics real-time simulation module with the executing mechanism characteristics comprises a spacecraft body, a flywheel and flexible appendage dynamics; the flexible spacecraft kinematics real-time simulation module can select different types of attitude description modes according to task requirements; the attitude measurement module can select different real sensors and sensor simulators according to the task requirements; the attitude control module comprises a conventional PID control method, a robust control method and the flexible spacecraft attitude control method in allusion to flywheel low-speed friction, and switching can be carried out according to the task requirements of the system; and the executing mechanism module comprises a real flywheel and a thruster simulator.

The invention relates to a visual dynamic simulating device for deposition in a gas hydrate pipeline, which is used for simulating the generation, the transportation and the deposition of gas hydrate in high-pressure high-speed air flow and can be used for summarizing the high-speed motion characteristic, the transportation mechanism and the deposition rule of a pipeline gas-solid phase. The invention has the technical schemes that: the top end of a low-pressure gas storage tank is provided with a temperature sensor and a pressure sensor, the outlet end of the low-pressure gas storage tank is connected with a high-pressure gas pump and then is connected with a high-pressure gas storage tank, and the top end of the high-pressure gas storage tank is provided with a pressure sensor; the outlet end of a liquid storage tank is connected with a metering pump, and the upper end of a gas-liquid separator is connected with a vacuum pump and a tail gas treating device; the top end of a high-pressure reaction tube is connected with an outlet electrical heating insulation pipeline, and the bottom end of the high-pressure reaction tube is provided with a pressure sensor and an inlet electrical heating insulation pipeline; and a data acquisition system is formed by a data acquisition card, a computer, a cold light source and a high-speed camera, and a pipeline temperature attitude control system is additionally arranged. According to the visual dynamic simulating device disclosed by the invention, the generation process, the transportation process and the deposition process of the gas hydrate in the high-pressure high-speed air flow can be really simulated, and the visual dynamic simulating device is used for evaluating a gas hydrate inhibitor.

The invention provides a method for controlling a flexible structure and a self-adaptive changing structure by a radial basis function (RBF) neural network, belonging to the field of aviation. The method aims at solving the problem that the existing method can not preferably solve the conflict between the shake of a solar sailboard and the high-precision control target of an attitude control system. The method comprises the following steps: an E1 input forming module is used for converting an inputted expected satellite attitude angle theta d into a response uE1, and outputting the response uE1 to a nominal system and a flexible spacecraft; the nominal system is used for outputting expected satellite attitude information xm (t), and the flexible spacecraft is used for outputting practical satellite attitude information x (t) to obtain an error e (t) by comparing the xm (t) with the x (t); a sliding film face control module is used for obtaining a proper sliding film face s according to the error e (t), and transmitting the s to the RBF neural network and a self-adaptive locoregional control module; the self-adaptive locoregional control module is used for outputting a self-adaptive locoregional control u* to the RBF neural network; and the RBF neural network is used for obtaining and adjusting a locoregional control un and an adding result between the un and the uE1 according to the s and the u* to control the satellite attitude of the flexible spacecraft to achieve an expected value.

Various embodiments of the present invention include systems and methods for assessing the performance of an actuator of an attitude control system (ACS), such as a control moment gyroscope (CMG). In one embodiment, a system includes a support bracket assembly coupled to an actuator, wherein the actuator is configured to generate an output torque. The system also includes at least one sensor assembly that includes a sensor configured to measure the output torque about at least one axis of the support bracket assembly while the support bracket assembly remains substantially motionless.

The invention discloses a rigid spacecraft performer multi-fault diagnosis and fault tolerance control method. According to the method, the kinetic and dynamic model of a rigid spacecraft attitude control system is put forward, a fault model for existing of both the performance failure fault and the deviation fault of a rigid spacecraft is established, and then a fault detection observer adopting the adaptive threshold technology and a fault estimation observer based on the adaptive technology are respectively established so that online real-time detection and estimation of the fault time and the concrete situation of the fault can be realized, and finally a backstepping sliding mode fault tolerance controller is designed according to fault information established by the fault estimation observer. Attitude stabilization control of the rigid spacecraft under the condition of the performer efficiency damage and the deviation fault can be realized, and the influence of external disturbance on the system and the observers can also be considered in the design process. Besides, the fault detection observer and the fault estimation observer can be independently designed so that the engineering application can be more easily implemented.

The invention provides a method for performance evaluation of a spacecraft attitude control ground simulation system. According to the method, the credibility of a dynamic system, a kinematics system, a measurement system and a control system is studied based on the simulation system credibility theory, the overall credibility of the spacecraft attitude control ground simulation system is obtained through comprehensive calculation, and then the performance of the spacecraft attitude control ground simulation system is evaluated. According to the evaluation method, the credibility of the ground simulation system and an actual satellite attitude control system is considered from all aspects, simulation data are fully utilized, and the credibility of the ground simulation system is described objectively and quantitatively; the theoretical basis is reliable, the calculation process is simple, the application range is wide, and a new idea and reference are provided for performance evaluation study of other simulation systems.

A watercraft attitude control system using GPS and other motion inputs in order to predictively control thrust, steering and hull characteristics in ways that will prevent and minimize porpoising motion of a watercraft.

The invention provides a large flexible spacecraft interference compensation method based on a sliding mode disturbance observer. The compensation method comprises the following steps of a) establishing a spacecraft attitude control system [sigma1]; b) establishing an external system [sigma3], wherein the external system [sigma3] adopts an uncertain part of a spacecraft flexible appendage damping matrix and describes the sum of flexible oscillation and environment interference; c) designing a sliding mode disturbance observer, wherein the sliding mode disturbance observer estimates the value of the sum of flexible oscillation and environment interference; and d) combining a nominal controller and the sliding mode disturbance observer in the step c) to obtain a combined controller, wherein the combined controller compensates the sum of flexible oscillation and environment interference through the estimation value of the sum of flexible oscillation and environment interference.

The invention discloses a semi-physical simulation system for attitude control of a star-arrow integrated spacecraft, which relates to the semi-physical simulation system for control of the star-arrow integrated spacecraft. The invention solves the problem that the conventional semi-physical simulation system for the attitude control of the spacecraft cannot simulate the spacecraft from a launching point to an active operation stage attitude control system. A simulation signal input or output end of a real-time simulator is connected with a simulation signal output or input end of an onboard computer; a wireless signal input or output end of a stage wireless communication module is connected with a wireless signal output or input end of the real-time stimulator; and a signal output or input end of a ground wireless communication module is connected with a signal input or output end of a ground control module. The system is suitable for the stimulation of the attitude control of the star-arrow integrated spacecraft.

Various embodiments of the present invention include assemblies and methods for utilizing antennas with high gain in small satellites. In one embodiment, a satellite comprising a payload configured for transmitting data is provided. The payload may include various components of the satellite, such as the attitude control system, electrical power system, and / or communication system. The satellite may be configured to communicate with one or more ground stations. The satellite includes a support structure comprising at least one deployable panel, wherein the support structure houses the payload. The satellite also includes at least one antenna coupled to the support structure, wherein the deployable panel is configured to cover the antenna in a non-deployed state and to expose the antenna in a deployed state.