121 results about "Non singular" patented technology

The invention discloses a three-dimensional multi-missile cooperative guidance method with finite time convergence. The method comprises the steps that for an unknown target, a multi-missile cooperative guidance model with attacking angle constraint in three-dimensional space is established; by adaptive control, integral sliding model control and a finite time consistency protocol, an acceleration guidance law in the sight direction is established to make all missiles hit the target at the same time; through the adaptive control and non-singular fast terminal sliding model control, and the acceleration guidance law in the sight direction is designed to make the finite time convergence of a sight angular velocity rate and a sight angle of each missile achieved. According to the three-dimensional multi-missile cooperative guidance method with the finite time convergence, all the missiles can hit the target at a desired angle at the same time on condition that no maneuvering information of the target is known, and at the same time the occurrence of buffeting is avoided.

A limit time cooperative control method of a mechanical arm servo system includes: building the dynamic model of the mechanical arm servo system, and initiating the system state, sampling time and related control parameters; approximating the nonlinear input dead zone linearity in the system into a simple time-varying system according to the differential mean value theorem, and deriving a mechanical arm servo system model with an unknown dead zone; calculating the tracking error, the non-singular terminal sliding mode surface and the first derivative of a control system; selecting a neural network approximation unknown function on the basis of the mechanical arm servo system model with the unknown dead zone, designing a neural network limit time cooperative controller according to the system tracking error and the non-singular terminal sliding mode surface, and updating a neural network weight matrix. By the method, additional inverted compensation of a nonlinear dead zone can be avoided, sliding model high-frequency buffeting is reduced, and limit time fast tracking of the mechanical arm servo system is achieved.

The invention provides a local obstacle avoidance considering UUV moving object sliding mode tracking control method, which comprises the steps of detecting position information of a UUV, a moving object and an obstacle in real time, acquiring state estimation of the moving object at the moment k, building a relative motion model of the UUV, the moving object and the obstacle, autonomously switching between a tracking strategy and an obstacle avoidance strategy according to the relative positions of the UUV, the moving object and the obstacle based on the size of the object tracking radius and the obstacle avoidance safety radius, acquiring tracking control deviation according to the measurement feedback of the instruction speed, the course, the UUV navigation speed and the course changing angular speed, and carrying out calculation based on a horizontal plane non-singular terminal sliding mode controller so as to acquire thrust of a UUV propeller and course changing torque of a rudder at the moment k, and executing the above steps in a cyclic manner so as to realize tracking control for the moving object at the next moment. According to the invention, a local planning strategy in the complex environment is combined with a UUV dynamics model, and the tracking accuracy of the moving object is ensured under the premise the UUV navigation safety.

The invention discloses an adaptive terminal sliding-mode controller based mechanical arm trajectory tracking control method. The method includes the following steps: 1, establishing a rigid mechanical arm system dynamics model having n degrees of freedom rotating joints; 2, obtaining the measuring information of each joint angle q and angular velocity which is shown in the description of a mechanical arm through a photoelectric encoder, setting the expected angle q<d> and expected angular velocity which is shown in the description tracked by each joint, and calculating mechanical arm trajectory tracking errors [epsilon]1 = q - q<d> and the first derivative shown in the description of trajectory tracking error versus time; 3, establishing a novel non-singular terminal sliding-mode surface s according to the [epsilon]1 and [epsilon]2; and 4, designing the controlling moment tau of the driving motor of each joint of the mechanical arm according to the sliding-mode surface s, and establishing an adaptive rate which can adjust control gain to dynamically estimate system lumped disturbance upper bound. Under the circumstance that internal and external interference such as parameter perturbation and torque disturbance existing in the mechanical arm system, the method can perform real-time feedback so as to realize the accurate controlling of mechanical arm trajectory tracking based on the measuring information of each joint angle and angular velocity, and the controlling on the robustness of the whole course can be guaranteed.

A method for a fast and efficient construction of an elliptic curve cryptosystem is disclosed. In the present invention, a prime p of a special kind is chosen which constructs a finite field underlying the elliptic curve cryptosystem. Accordingly, the selected prime p is utilized to construct a non-singular elliptic curve of a special kind, and the elliptic curve cryptosystem parameters can be easily chosen and computed. Using such procedure, the present invention allows a fast and easy construction of a large variety of elliptic cryptosystems used in telecommunications.

The invention relates to a laser-tracker-based calibration method for a six-degree-of-freedom robot tool coordinate system. The method comprises: a laser tracker is arranged in front of a robot body at a distance of three meters; a pedestal and a target ball are fixedly installed on a flange plate; SA software is operated and a laser tracker is connected; the robot body is adjusted to be at a non-singular point position and a spatial position of the target ball at an attitude is recorded; the center of the flange plate is kept to be unchanged, the attitude of the flange plate is changed step by step and all attitude positions are recorded, the operation is repeated by 19 times to obtain spatial positions with serial numbers P1 to P20 at 20 attitudes; ball fitting is carried out on the twenty spatial position points by the SA software to obtain a sphere with the center of the flange plate as a centre of sphere; at an attitude Pi, a flange coordinate system {Tool000} is established; andunder the {Tool000} coordinate system, the Pi coordinate expresses a positional relationship between a tool and the flange coordinate system, and a tool coordinate system is determined based on the coordinate system positional relationship. According to the invention, the operation is simple and the calibration accuracy is high.

The invention discloses a bridge crane finite time trajectory tracking controller and a design method thereof. Firstly, a non-singular terminal sliding mode surface is introduced, and the advantages of a first-order sliding mode control method and a second-order sliding mode control method can be integrated together to obtain an absolutely continuous control input. Secondly, inspired by the static torque calculation method, a finite time controller is proposed. Through introducing the Lyapunov candidate function, the stability of a closed-loop system is analyzed, and the limited convergence time T is obtained. Through comparing the above controller, an LQR controller, an enhanced coupling nonlinear controller and a motion planning-based self-adaptive controller, the correctness and the effectiveness of the control method can be proved.

The invention relates to a disturbance observer based MEMS gyroscope prediction performance non-singular sliding-mode control method. The method comprises the following steps: in view of a gyrodynamics model of parameter perturbation and external time-varying disturbance, designing an adaptive update law of neutral network weight, and correcting the weight coefficient of the neutral network to realize effective estimation of unknown dynamics; introducing a performance function to limit the tracking error, and converting the limited tracking error into unlimited conversion error through errorconversion; designing a sliding-mode controller based on conversion error to realize prediction performance control on MEMS gyroscope; designing a non-singular terminal sliding-mode controller to realize feed-forward compensation of unknown dynamics while avoiding the problem of system singularity; designing a disturbance observer to perform estimation compensation on external disturbance. The method disclosed by the invention solves the problem that external disturbance, system singularity, overshooting and tracking error cannot be designed in advance, and enhances the control precision and further improves the performance of the MEMS gyroscope.

Methods and apparatus for generating a private-public key pair, for encrypting a message for transmission through an unsecure communication medium (30), and for decrypting the message are disclosed. The methods are based on the well-known McEliece cryptosystem or on its Niederreiter variant. More general transformation matrices Q are used in place of permutation matrices, possibly together with an appropriate selection of the intentional error vectors. The transformation matrices Q are non-singular n×n matrices having the form Q=R+T, where the matrix R is a rank-z matrix and the matrix T is some other matrix rendering Q non-singular. The new Q matrices, though at least potentially being dense, have a limited propagation effect on the intentional error vectors for the authorized receiver. The use of this kind of matrices allows to better disguise the private key into the public one, without yielding any further error propagation effect. Based on this family of Q matrices, the presently proposed cryptosystem enables the use of different families of codes than Goppa codes, such as RS codes, by ensuring increased public key security.

The invention discloses a dynamic positioning method using an underwater detection and operation robot. The method solves the problem of uncertainty caused by a reason that dynamic positioning is disturbed by waves, and in combination with the developed novel underwater detection and operation robot, based on a hydrodynamic digital simulation recognition parameter method, a dynamic model is established for dynamic positioning analysis of six degrees of freedom. The position and the heading of the underwater robot are acquired via a sensor, the state of the underwater robot is estimated in real time by adopting an adaptive unscented Kalman filter algorithm, the thrust is compensated by adopting non-singular terminal sliding mode control to reduce the influence of random such as waves and the like, and a force and torque distribution strategy is designed according to the positioning error. The method has a good dynamic positioning effect, and can quickly adjust the dynamic distribution strategy after disturbance to reduce the negative effect of the disturbance.

The invention discloses an underwater auxiliary oil recovery control system and a dynamic positioning method thereof. Focusing on an uncertainty problem that a motion of the underwater auxiliary oil recovery robot is interfered by ocean current, combining the manufactured underwater auxiliary oil recovery robot, the invention establishes a dynamical model based on a fluid dynamic numerical simulation identification parameter method and performs six-degree-of-freedom dynamic positioning analyzing. A position and a heading of the underwater auxiliary oil recovery robot are obtained by a sensor;a state of the underwater robot is estimated in real time by adopting an adaptive unscented Kalman particle filtering algorithm based on a hybrid genetic algorithm-Markov chain Monte Carlo method (GA-MCMC); a fast terminal reaching law is introduced into a non-singular fast terminal sliding mode control to compensate thrust, so that influence caused by interference such as the ocean current is reduced; and then a force and torque distribution strategy is designed according to a positioning error. The method has a good dynamic positioning effect, and can quickly adjust the dynamic distributionstrategy after being interfered in order to reduce the interference impact caused by random ocean current.

This invention discloses a method and system for generating a private key and a corresponding public key. These keys can be used for encrypting a message into a cipher-text for transmission through an insecure communication channel, and for decrypting said ciphertext into a clear plaintext. The goal of the present invention is to provide encryption and decryption methods of the McEliece type which are capable of improving the security level of a post-quantum cryptosystem. In one embodiment, this object is achieved by three methods: a method for creating a public key from a private linear code generator matrix, a method for encrypting a message into a ciphertext and a method for decrypting the cipher-text into a plaintext. The key generation and encryption methods of the present invention comprises the following steps:

• • selecting an [n, k] linear code generator matrix G_s=[g₀ , . . . , g_n] over GF(q) as the private key, where k, w, n and q are positive integers and where g₀ , . . . , g_n−1 are length k column vectors; selecting k×1 random matrices C₀ , . . . , C _w−1; selecting a k×k non-singular matrix S; selecting an (n+w)×(n+w) matrix A; selecting an (n+w)×(n+w) permutation matrix P; and setting the public key as G=S[g₀ , . . . , g_n−w, C₀ , . . . , g_n−1, C_n−1]AP.
  • receiving the public key G, which is a k×(n+w) matrix over a finite field GF(q); generating an error vector e having elements in GF(q) and having a predetermined weight t; and encrypting a message vector m, to a ciphertext vector y=mG+e.

The main difference between the proposed cryptosystem and known variants of the McEliece cryptosystem consists in the way the private generator matrix is disguised into the public one by inserting and mixing random columns within the private generator matrix.

The invention relates to a predetermined time multi-agent system consistency tracking control method. The method comprises the following steps: designing a predetermined time distributed observer to estimate a tracking error within predetermined time; determining distributed observer parameters according to preset time; designing a non-singular terminal sliding mode consistency control protocol inpreset time, so that the follower multi-agent system can track the track of the leader agent system in the preset time; determining controller parameters which can ensure the continuity and the microcosmic property of the sliding mode surface and eliminate the control singularity; and deploying the proposed distributed observer and consistency control protocol on each follower agent to realize predetermined time consistency tracking. Compared with an existing fixed-time consistency scheme, the method has the advantages that the convergence time estimation with lower conservative property canbe obtained, and the conservative property of controller design can be reduced. Therefore, the method disclosed by the invention shows a wide application prospect in the application of a multi-agent system with higher requirements on control precision and convergence time.

The invention relates to a method for active obstacle avoidance trajectory planning and stable tracking control of a two-wheeled self-balancing vehicle, which comprises an obstacle avoidance trajectory planning method based on a circular arc and a transition curve and a stable tracking control method based on a non-singular terminal sliding mode algorithm and a nested saturation algorithm. Trajectories planned by a local trajectory planning method comprise a lane changing trajectory, an overtaking trajectory and a lane combining trajectory. The non-singular terminal sliding mode algorithm controls a full-drive steering subsystem of the two-wheeled self-balancing vehicle, and the nested saturation algorithm controls an under-drive forward subsystem of the two-wheeled self-balancing vehicle. The obstacle avoidance trajectory planned according to the invention has the characteristics that the trajectory is gentle in curvature change and stable tracking of the under-drive two-wheeled self-balancing vehicle is facilitated; and the stable tracking control algorithm provided by the invention can enable the two-wheeled self-balancing vehicle to stably track the planned obstacle avoidance trajectory at a large initial value of the vehicle body inclination angle and keep the vehicle body to be stable at the same time, and thus active obstacle avoidance of the two-wheeled self-balancing vehicle is achieved.

The invention provides an adaptive fault tolerance control method for a vertical take-off and landing reusable launch vehicle. The method comprises the steps of: Step 1: obtaining a guidance command;Step 2: establishing a landing section fault tolerance control model; Step 3: designing a fixed time convergence and expansion state observer; step 4: designing a non-singular fast terminal sliding mode surface; and Step 5: designing an adaptive fault tolerance controller. According to the adaptive fault tolerance control method, this design pattern not only effectively improves the rejection capability of the system to the complex external interference and the adaptive fault tolerance performance under various engine failure modes, but also guarantees the rapid and accurate tracking of the attitude guidance command.

The invention provides a non-singular terminal sliding-mode control method for a Buck converter with constant switch frequency and relates to a sliding-mode control method for the Buck converter. The problems that when a linear sliding-mode control method is adopted, the response speed of the Buck converter is low, the voltage output quality is low, and the response speed and the precision of output voltage of the Buck converter are directly influenced are solved. According to the method, based on an average state model of the Buck converter, by changing a duty ratio of a switch device, trigger pulses are generated for controlling on or off of the switch device, and then constant switch frequency voltage output of the Buck converter is achieved; a non-singular terminal sliding-mode controller of the Buck converter is designed, the advantages of strong robustness, overall finite time constriction, high stability precision and the like of the controller are utilized for overcoming the disturbance influence of load resistance, direct-current input voltage and the like, and therefore the quality of the output voltage is improved.

The invention discloses an underwater carrier terminal sliding-mode control method based on time delay estimation. According to the method, the lump uncertainty of a closed-ring control system of an underwater carrier is estimated by adopting the time delay estimation technology, so that the whole control algorithm is independent of a system model; and on the basis, a quick non-singular terminal sliding mode hyperplane is combined with a quick terminal sliding mode reaching law to deduct a time delay estimation-based underwater carrier continuous quick non-singular terminal sliding mode trajectory tracking control method. The method is independent of system model, is easy for engineering application, can ensure relatively high control accuracy and rapid system response, and is applicable to underwater carrier trajectory tracking control under complicated work conditions.

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 relates to a fixed-time consistency tracking control method of a second-order multi-agent system under directed communication. The method comprises the steps of: (1) designing a fixed-time distributed observer for each follower, so that each follower obtains the state information of a leader within a fixed time; (2) determining an expression of an upper bound of an observation time;(3) designing a fixed-time non-singular terminal sliding mode consistency control protocol, so that a follower multi-agent system can track the trajectory of a leader multi-agent system within the fixed time; and (4) determining the expression of the upper bound of a convergence time. Compared with the existing fixed-time consistency scheme, the fixed-time consistency tracking control method provided by the invention has the advantages of reducing the communication resource consumption and the channel requirements, reducing the cost, and improving the system reliability and the scalability ofthe consistency protocol.

The invention discloses a non-uniform array design and direction of arrival (DOA) estimation method and mainly aims at solving the problems that arrangement is inflexible and computation complexity isrelatively high in the prior art. A realization process of the method comprises the following steps: according to maximum freedom degree of a nested array, determining head and tail position coefficients of a non-uniform array; calculating position coefficients of all the virtual array element positions meeting the non-uniform array and contained in a differential synthetic matrix; according to the position coefficients, finally obtaining positions of array elements of the non-uniform array; according to received data, calculating a data covariance matrix and vectorizing, so that received data r of a virtual differential synthetic array is obtained; performing redundancy elimination on the r and sorting to obtain received data of a virtual array, and then obtaining a non-singular matrix vof the virtual array; constructing a linear operator, and obtaining a signal subspace by estimating the linear operator; and constructing a selection matrix to obtain a rotation matrix, and finally estimating a direction of arrival by virtue of the rotation matrix. The method disclosed by the invention has the advantages that array configuration is flexible, characteristic decomposition does notneed to be performed on the data covariance matrix and spectral peak search does not need to be performed on the whole airspace angle under the same conditions.

The invention discloses a decoration method capable of forming a raised picture on a ceramic green body, which belongs to the technical field of ceramic decoration and solves the problems of unnatural rise of the profile of the raised pattern picture on the green body, non-singular production, limited glaze and pattern raised height and undesirable embossment effect of the prior art. The method comprises: a step of preparing a coating, in which 40 to 60 weight parts of color chips and 35 to 65 weight parts of 95 weight percent ethanol are proportioned in a container, and when the color chips are dissolved completely and the solution become pasty, stirring the solution uniformly; and a step of making the raised picture on the green body, in which the green body is completely cleaned, a picture is drawn on the green body with the prepared coating, the coating is allowed to be dried completely after the picture is drawn, the picture is cleaned slightly by sponge dipped with water repeatedly till the picture shows a three-dimensional effect, and the raised picture is made by biscuiting and color decoration. With raised picture, the decoration effect and quality are more outstanding; and the raised part is natural and smooth without any unnatural feel that is offered by a caving mold. The method can draw natural and vivid pictures on three-dimensional and flat green bodies freely so as to create artistic conception and special artistic effect.