1531 results about "Sliding mode 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.

A modular exoskeletal device adapted to fit the lower extremities of a patient during rehabilitation. The device has only two actuators during the standing stage of rehabilitation. Two additional actuators can be added, as modules, during the walking stage of rehabilitation. The actuators are affixed to the patient and provide controlled motion to at least one of the joints of the patient. A stationary control unit is separated from the patient. The control unit communicates with and directs the actuators, and has a hybrid control algorithm, such that the actuator forces are adjusted as the patient regains control of some joint motions, which is based upon the sliding-mode control theory. A back brace is affixed to the patient and helps to keep the torso of the patient in a stable, substantially vertical position.

A medical robotic system has a joint coupled to medical device or a slave manipulator or robotic arm adapted to hold and/or move the medical device for performing a medical procedure, and a control system for controlling movement of the joint according to user manipulation of a master manipulator. The control system includes at least one joint controller having a sliding mode control for reducing stick-slip behavior on its controlled joint during fine motions of the joint. The sliding mode control computes a distance to a sliding surface, computes a reaching law gain, and processes the distance and reaching law gain to generate a sliding mode control action that is in absolute value less that a maximum desired feedback control action. The sliding mode control action is then further processed to generate a feedback torque command for the joint motor.

Higher Order Sliding Mode (HOSM) control techniques are applied to the Guidance Control (G&C) of interceptor missile in which velocity may be steered by combination of main thrust, aerodynamic lift and lateral on-off divert thrusters, and attitude may be steered by continuous or on-off actuators. Methods include the pointing of the seeker, its associated estimation processes, a guidance law that uses concurrent divert mechanisms, and an attitude autopilot. The insensitivity of the controller to matched disturbances allows the concurrent usage of the divert mechanisms without adverse effect on the accuracy. The controller also allows the de-coupling of the control of roll, pitch and yaw channels, and usage quaternions to represent body attitude and it provides control perfect robustness. While it conceivable to design separately the components of the G&C method, it is widely accepted that designing them in an integrated fashion usually produces a better result.

The invention pertains to the technical field permanent magnet motors, and relates to a permanent magnet motor sliding mode control strategy. The permanent magnet motor is controlled by adopting double-closed speed current. The permanent magnet motor sliding mode control strategy is characterized in that a sliding mode speed controller and an extended sliding mode observer are adopted in the control strategy, the sliding mode speed controller adopts an exponential approach law containing the speed error and the sliding mode surface information, the deviation between a given rotating speed and a feedback rotating speed is taken as the input quantity, and a q-axis current given value is outputted through the sliding mode control quantity; the extended sliding mode observer is used to estimate the rotor position, the rotating speed and the load torque on a real-time basis, the rotating speed and the rotor position are used to provide the information of speed closed-loop control and coordinate transformation, and the load torque is compensated to the sliding mode speed controller, so that the high-accuracy vector control of the permanent magnet motor can be realized. The control strategy of the invention can be used to make the system fast track a given speed in the dynamic state, reduce the speed overshoot and the current fluctuation, and improve the disturbance resistance performance of the system.

A power-conversion control system includes an inverter, a cycloconverter, and a sliding mode controller. The inverter is operable to receive a DC voltage input and produce a first AC voltage output having a first frequency. The cycloconverter has a plurality of bidirectional switches, and is operable to receive the first AC voltage and to synthesize a second AC voltage having a second frequency that is lower than the first frequency. The sliding mode controller is operable to provide a control signal to command the plurality of bidirectional switches to turn OFF and ON when the first AC voltage is at a zero crossing condition. The sliding mode controller is also operable to selectively adjust the frequency and amplitude of the second AC voltage.

The invention relates to a horizontal and vertical coordination control method for trajectory tracking of an intelligent vehicle. For association and coupling characteristics of horizontal and vertical dynamics of the intelligent vehicle, a horizontal and vertical coordination controller for trajectory tracking of the intelligent vehicle is designed. By applying a model prediction control and sliding mode control algorithm, the opening degree of a throttle valve of an engine, the pressure of a main braking cylinder and the deflection angle of a front wheel are cooperatively controlled. In thedesign of a horizontal MPC, the state amount of the vehicle is selected at the formula which is shown in the description, and the state amount (vertical speed vx) is real-time changable vehicle speedoutput by the vehicle after vertical control; vy is a horizontal speed at the mass center of the vehicle; the formulas which are shown in the description are the heading angle and heading angle speedat the mass center of the vehicle; Y and X are a horizontal position and a vertical position under world coordinates. According to a horizontal and vertical coordination control system, the intelligent vehicle efficiently and stably tracks an expectation trajectory at the expected speed. Large-steering operation can be remarkably improved, and the horizontal stability of the intelligent vehicle inthe trajectory tracking process is improved.

The invention discloses a non-cooperative spacecraft attitude estimation method based on virtual sliding mode control, and belongs to the technical field of non-cooperative spacecraft navigation. The non-cooperative spacecraft attitude estimation method comprises the following steps: utilizing a virtual control sliding mode controller based on the Lyapunov principle; using target satellite absolute attitude obtained by a stereoscopic vision system as a control objective; according to motion characteristics of the target satellite, establishing a virtual satellite motion model of the target satellite; using a kinetic model of the virtual satellite as a controlled member to obtain attitude parameters of the virtual satellite; using attitude parameters estimated by the virtual satellite and the target satellite absolute attitude obtained by the stereoscopic vision system as controlled input, and calculating the virtual revolving moment on the motion model of the virtual satellite through the virtual sliding mode controller, so as to realize the estimation of the target satellite attitude parameters by the virtual control sliding mode controller. The non-cooperative spacecraft attitude estimation method disclosed by the invention is low in calculated amount, and can still achieve higher convergence rate and higher precision when the initial error of the state variables is high or the system error emerges, so as to meet the requirements of the high performance navigation system.

The invention discloses a trajectory tracking sliding mode control method for a spraying mobile robot. The method comprises the following steps of: performing mechanism analysis on a mobile robot, and establishing a mobile robot kinematic model with non-integrity constraint; establishing a controlled object mathematical model of each branch controller of a wheeled mobile robot provided with a motor driving shaft disturbance term; identifying a traveling path by utilizing a computer vision system, and determining an expected motion track of each branch driving motor according to the kinematic model deduced in the previous step; detecting the rotating speed of the motor, calculating the actual motion angular velocity and actual motion angular acceleration of left and right driving motors of the mobile robot, and calculating the deviation and deviation derivative between the expected angular velocity and the actual angular velocity of each driving motor; establishing a sliding mode switching function which meets the speed control requirement of the driving motor; determining the sliding mode controller control quantity of the left and right driving motors of the mobile robot on the basis of the sliding mode surface function s; and respectively transmitting the control quantity of the motor of the mobile robot to the left and right driving motors.

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.

The invention discloses a method in a boat control field and especially relates to the sliding mode-reverse step double loop trace tracking control method of an underactuated unmanned surface vehicle.The method comprises the following steps of firstly, establishing a three-degree-of-freedom motion mathematical model of the heading, the surging and the swaying of the unmanned surface vehicle; then, through an integrated pose sensor, measuring the current position information of the unmanned surface vehicle, combining the real-time position and the reference trace of the unmanned surface vehicle, calculating an error under a boat body coordinate system; and then, designing a kinematic loop trace tracking controller based on a backstepping method, and designing a dynamic loop trace trackingcontroller based on a sliding mode control algorithm. Through a sliding mode-reverse step double loop trace tracking controller, the trace tracking control of the unmanned surface vehicle Is realized,the unmanned surface vehicle can track a linear trace, and the stability and accuracy of unmanned surface vehicle navigation can be increased.

The invention discloses an active fault tolerance control method of a four-rotor aircraft based on a sliding-mode observer. The active fault tolerance control method is provided by considering that a performer may have faults when the four-rotor aircraft is in a state delay condition and combining the sliding-mode observer with sliding-mode control. The sliding-mode observer is designed, linear transformation is carried out on the system, faults of the performer are reconstructed on the basis of the ideal of equivalent error injection, compensation control is added into sliding-mode control by utilizing the reconstructed estimation value of the performer faults, and a complete active fault tolerance controller is formed. According to the invention, the sliding-mode observer is designed, the faults are reconstructed and estimated, online adjustment of the controller gain is realized, the provided control law is optimal, the control precision and response speed of flight of the four-rotor aircraft are effectively improved, and a design basis of the fault tolerance controller is provided for the complex four-rotor aircraft with performer faults. The method can be applied to active fault tolerance control for the four-rotor aircraft with time variation and time lag.

The invention discloses a nonlinear robust controller design method based on back-stepping and sliding mode control technologies and aimed at a nonlinear model of a quad-rotor unmanned plane. A sliding mode controller of a speed-constant reaching law is designed to an attitude angle system of the quad-rotor unmanned plane, and rapid tracking for the attitude angle is ensured. To realize track tracking for the spatial position of the quad-rotor unmanned plane, a sliding mode surface and a virtual control quantity are constructed according to a stepping back control idea to realize nonlinear control law design and system stability design from the kernel to the external layer of a system. After an equation of the related virtual control quantity is obtained, an expected track value of the attitude angle is obtained by solving the equation via arithmetic inverse operation, and a design method of the speed-constant reaching law is used to determine a final input control law of the quad-rotor unmanned plane system. According to the method of the invention, the characteristic that sliding mode control is uncertain for the model and insensitive to external interference is utilized, robust trace tracking for the nonlinear quad-rotor unmanned plane can be controlled under interference.

The invention discloses an adaptive control system based on a radial basis function (RBF) neural network sliding mode control for a micro-electromechanical system (MEMS) gyroscope, and the system comprises a gyroscope and a control circuit, wherein the control circuit comprises a sliding mode controller and an RBF neural network; the difference of displacement of the three-axis gyroscope in the directions of three coordinate axes x, y and z and displacement of a reference model is taken as the input of the sliding mode controller. In the adaptive control system, an adaptive sliding mode control method is applied in controlling the gyroscope, so as to improve the stability and reliability of the system; and the RBF neural network is adopted to carry out adaptive learning on upper boundary of uncertain interference, thus reducing the influence of measurement error and external interference, effectively lowering the occurrence of buffeting, and achieving a better control effect.

The present invention is directed to a control system for a MEMS device, such as a MEMS mirror, that uses sliding mode analysis to accurately and predictably control the position of the mirrors in a MEMS device. The present invention also uses the capacitance of the mirror to detect the position of the mirror. In one embodiment, a MEMS mirror device mounted on a substrate is described that includes, a micro mirror that is pivotable about an axis, a first conductive layer on the mirror, a second conductive layer on the substrate, the first and second conductive layers form a first capacitor for determining the position of the mirror. The sliding mode control can be implemented using various drive mechanisms, including electrostatic drives. When used with electrostatic drives, conductive layers that create the capacitors can also be used to drive the mirror. The detection-drive system can be time multiplexed to simplify implementation and to avoid cross talk. An application Specific Integrated Circuit (ASIC) can be used to control the detection and drive of the mirrors.

The invention relates to a method for controlling an index time-varying slide mode of flexible spacecraft characteristic shaft attitude maneuver, and belongs to the technical field of spacecraft control. The method comprises the steps that firstly, a system dynamically equivalent model, a dynamic model and a flexible vibration model are established under a spacecraft system, then, the vibration frequency and the damping ratio parameter of a closed loop system with the index time-varying slide mode control law are calculated, and a single-shaft multi-modality filtering input shaping device with a characteristic shaft as a rotary shaft is designed according to the designing method of the single-shaft input shaping device to restrain flexible vibration in three-shaft motion. Meanwhile, a state observer is designed to estimate flexible modal information in real time, and the method for controlling an output feedback index time-varying slide mode is formed. At last, saturability analysis is conducted on control torque so as to satisfy the physical saturation constraint of the control torque. By means of the method, the application range of existing input shaping is expanded, the input shaping technology is expanded from single-shaft maneuver to three-shaft maneuver, the self-robustness of filter input shaping is enhanced, and the purpose that the attitude maneuver path of the spacecraft is the shortest is achieved.

The invention relates to a motor rotating-speed tracking control method based on a self-adaptive fuzzy neural network, wherein rotating-speed and current double closed-loop control is adopted, an outer ring is a rotating-speed ring, a sliding-mode control theory-based fuzzy neural-network controller (SMFNN) is designed, an inner ring is a current ring, and a PI (Proportional-Integral) controller is adopted; a fuzzy neural-network rotating-speed controller comprises two parts, wherein one part is a PID (Proportional-Integral-Derivative) controller, and the other part is the fuzzy neural network, online real-time learning is carried out through the fuzzy neural network by utilizing a parameter correcting method designed on the basis of the sliding-mode control theory, and the two parts jointly act to obtain the output ir of the rotating-speed controller, i.e. a difference obtained by subtracting the output iFNN of the fuzzy neural network from the output iPID of the PID controller is used as the output ir of the rotating-speed controller. The control precision and the anti-interference performance of a motor speed-adjusting system can be improved through the control strategy of the motor rotating-speed tracking control method.

The invention discloses a permanent magnet synchronous motor sliding-mode control strategy based on a novel reaching law. The permanent magnet synchronous motor control strategy adopts speed and current double-closed-loop control, a current loop adopts a PI (proportional-integral) controller, and a rotating speed loop adopts sliding-mode control based on the novel reaching law; a speed regulator adopts a novel speed change reaching law containing speed errors and sliding-mode surface information, deviation of a set rotor angular speed and a feedback rotor angular speed is used as the input quantity, and a q-axis current set value iq<*> is output through the sliding-mode control quantity. With the adoption of the strategy, the problems that a traditional reaching law is slow and large in steady-state buffeting are solved, the set rotating speed can be tracked quickly in a dynamic state, speed overshoot and current fluctuation are reduced, the harmonic content, produced by high-frequency buffeting, of a system can be decreased in a steady state, the performance of the system is greatly improved, and high-precision vector control on the permanent magnet synchronous motor speed regulating system is realized.

The invention discloses a trajectory tracking control method for a mobile robot based on a sliding mode variable structure. According to the trajectory tracking control method, advantages and disadvantages of different reaching laws are comprehensively analyzed, and a reaching law with better rapidity and stability is proposed and designed. The reaching law is composed of two items, wherein the first item is that the system state is controlled to rapidly approach to a sliding mode surface when being far away from the sliding mode surface, and the second item is that the system state is controlled to keep stable running in the sliding mode surface. The trajectory tracking control method comprises the steps of firstly building a kinematics model and a trajectory tracking error model of the mobile robot, and deducing a mobile robot trajectory tracking error differential equation; and then designing a switching function based on the sliding mode variable structure, and deducing a sliding mode control law according to the designed reaching law, wherein the control law can enable the mobile robot to rapidly converge to an expected trajectory and expected speed. It is indicated by MATLAB numerical simulation that the trajectory tracking control method can effectively weaken a chattering phenomenon in the tracking process and improve the trajectory running accuracy. In addition, the trajectory tracking control method has good stability and robustness.

The invention provides a sliding-mode control method for parameter-free driving-insufficient UUV (Unmanned Underwater Vehicle) vertical plane route tracking. The sliding-mode control method comprises the following steps: I, performing initialization; II, acquiring a current state of a UUV; III, establishing an error equation of the horizontal plane of the driving-free UUV so as to obtain position deviation values xe and ze and course deviation value theta e; IV, according to a sliding-mode control method, respectively designing traveling speed sliding-mode self-adaptive control rules, position sliding-mode control rules and trimming angle sliding-mode self-adaptive control rules, controlling propelling force Xprop, an excepted traveling speed U and a torque Mprop, wherein eu is 0, xe is 0 and theta e is 0; V, designing fuzzy control rules for a boundary layer, setting k to be equal to k+1, turning to step II, and updating control rules and self-adaptive rules of a next time. By adopting the sliding-mode control method, a controller for stabilizing a system can be designed only according to a vertical surface kinetic model, self-adaptive rules can be designed for water kinetic parameters with uncertainties, furthermore a control system can be relieved from dependency on parameters, the system has robustness, and the influence of the uncertainties on the sliding-mode control approaching process can be reduced.

The invention provides a coordination control method for vehicle path tracking and stability. The method includes the following steps: step S1. performing vehicle modeling; step S2. performing estimation on a vehicle state and system interference based on Kalman filtering; and step S3. performing integrated control on the vehicle path tracking and stability. The method establishes a vehicle dynamics model and a path tracking model, and designs an estimation method of the vehicle state and steering system interference. An upper-layer controller is designed by using a sliding mode control method, which aims to ensure the stability of a vehicle itself while reducing course deviation and lateral deviation during a path tracking process. In a lower-layer controller, a method for optimal distribution of a wheel tire force is designed, and according to requirements of the upper-layer controller and combining yaw and roll stability conditions of the vehicle, directional control distribution ofthe wheel tire force is achieved. The coordination control method can ensure that a wheel independently drives the smart automobile to achieve a path tracking effect, and also ensures lateral and roll stability of the smart automobile itself.