151 results about "Sign function" patented technology

A digital vanity display system for a motor vehicle is presented, whereby a digital screen is connectable to the interior or exterior of the vehicle and a given message or symbol can be displayed therefrom via the driver or passenger's wireless input thereto. The display device includes a digital display having an antiglare coating for clarity, along with a display body for housing the system elements that allow for the sign operation, wireless communications, and power. A handheld device within the vehicle, such as a phone or tablet, is wirelessly paired to the display system such that inputs from the user can be wirelessly communicated thereto to update the sign. It is contemplated that the sign function as a vehicle personalization device, a messaging system for nearby motorists, a warning sign, and a traffic signal between vehicles.

The invention discloses a permanent magnet synchronous motor state estimation method based on a sliding mode back EMF observer. According to stator voltage and stator current detected in real time, a sigmoid function is used to substitute a sign function, and the sliding mode back EMF observer is constructed to estimate the back EMF. The type of the sliding mode back EMF observer is characterized in that the observer is insensitive to switch noise and has a filtering characteristic, thus the filtering of the estimated back EMF through a low-pass filter is not needed. After the normalization processing of the back EMF, a rotor position and speed information are extracted through a PI-I structure phase-locked loop position observer equivalent to a simplified Kalman filter. The permanent magnet synchronous motor state estimation method of the invention has good estimation performance even in the condition of noise and motor parameter changes, the chattering phenomenon in a traditional sliding mode observer is reduced, and the dynamic tracking performance and estimation precision of the rotor position and speed are improved.

The invention relates to a route selection method for analyzing a first principal component by utilizing a principal component of a zero-sequence current matrix of a faulty feeder line, belonging to the technical field of relay protection of a power system. The route selection method comprises the steps of: after single-phase earth fault happens to a distribution network with a neutral point grounded through an arc suppression coil, starting up a route selection device to firstly calculate an absolute value of a sum of zero-sequence currents of all the feeder lines in a short time window after the fault, and then realize the judgment of a bus fault and a feeder line fault through the size relationship of the value and a set threshold value; when the feeder line fault is determined, building a zero-sequence current matrix of each feeder line to analyze the principal component so as to obtain each principal component value of each zero-sequence current matrix, and multiplying a sign function of each element of the first principal component by a sign function of the sum of the sign functions of each element of the first principal component, respectively; finally, realizing the fault route selection reliably based on the size relationship of the value and a zero value. The route selection method for analyzing the first principal component by utilizing the principal component of the zero-sequence current matrix of the faulty feeder line improves accuracy and reliability of route selection.

The invention discloses a method for online detecting an RFID electronic tag. The method particularly comprises the steps of setting up the mapping relation of the ID numbers of RFID chips in a working position and the position of the tag in real time in the process of carrying out RFID chip packing on the working position, simultaneously reading the ID of all the RFID chips in the working position after working position packing is completed, comparing the read ID of the RFID chips with the mapping relation of the ID of the RFID tags in the working position and the positions of the RFID tags, confirming ID with missing reading, and confirming that the tag corresponding to the ID is an inferior-quality product. The invention further provides a device for online detecting the RFID electronic tag. The device comprises an X-direction feed mechanism, a Y-direction feed mechanism, a reader-writer, a processor, a marking mechanism, a clamping mechanism and a shielding case. The method and device can complete the read-write and signing functions of multiple tags, is suitable for online detection of the RFID tags with multiple lines and multiple columns, can greatly improve detecting efficiency, and is high in automation degree, stable and reliable.

The invention discloses a self-regulating error symbol integration robust control method for a direct-drive motor system. The method comprises the steps of establishing a mathematical model of the direct-drive motor system; designing a self-regulating error symbol integration robust controller; carrying out stability certification on the direct-drive motor system by using the Lyapunov stability theory, and acquiring a result of the global asymptotic stability of the system by using the Barbalat lemma. The self-regulating error symbol integration robust control method integrates the idea of self-adaptive control based on a traditional error symbol integration robust control method, and designs a controller gain self-regulating law so as to carry out on-line regulation on an integration robust gain value of the RISE controller. The self-regulating error symbol integration robust control method effectively solves problems of randomness, conservation, limitation and potential high-gain feedback in symbolic function gain regulation of a traditional RISE control method, and acquires better tracking performance.

The invention discloses a permanent magnet synchronous linear motor sliding-mode control method based on the variable exponential reaching law. The method includes the steps that 1, coordinate transformation is conducted on a prototype motor equation, and a PMSLM mathematical model in a d/q coordinate system is built; 2, a PMSLM double closed-loop servo control system composed of a current loop and a velocity loop is built; 3, a linear switching function is selected, and an exponential sliding-mode control law is obtained according to the exponential reaching law; 4, a saturation function replaces a sign function in the sliding-mode control; 5, an integration element is introduced on the basis of the switching function, and a variable exponential sliding-mode control law is obtained through the exponential reaching law; 6, non-linear relationship of sliding-mode gains and velocity errors is achieved. According to the permanent magnet synchronous linear motor sliding-mode control method based on the variable exponential reaching law, a current-velocity double closed-loop decoupling control structure is adopted, according to the chattering problem in the sliding-mode control, an integral switching surface and the variable exponential reaching law are introduced on the basis of a conventional sliding mode controller, the disturbance caused by load changes is effectively inhibited, and the tracking performance of the velocity and the robustness of a system are significantly improved.

The invention provides a mathematical formula display method and a mathematical formula display system based on hypertext markup language (HTML) 5 canvas. The mathematical formula display method comprises the steps of establishing the canvas through a canvas establishment module, establishing characters and a sign function database through a controller, establishing a mathematical formula structural control function database through the controller, writing a mathematical markup language (MathML) mathematical formula through a MathML mathematical formula module, analyzing the MathML mathematical formula through a formula processing module, drawing the MathML mathematical formula on the canvas according to the characters, contents of the sign function database and contents of the mathematical formula structural control function database, and outputting and displaying the mathematical formula. According to the mathematical formula display method and the mathematical formula display system based on the HTML 5 canvas, a simple and efficient HTML5 technique, a simple and efficient JavaScript technique and a simple and efficient MathML technique are provided through a canvas function of the HTML5 and the normalization of the MathML in mathematical formula expression, and the mathematical formula is rapidly and efficiently displayed on a webpage through analysis of the MathML mathematical formula.

The invention relates to a control method and device for eliminating system buffeting during sliding mode control of a linear motor. In the method, a sign function in the conventional sliding mode control formula is replaced by a diffusion hysteresis function, so that control voltage on a mover coil is evaluated. Due to the soft switching property of the diffusion hysteresis function, buffeting during sliding mode control is eliminated. Parameters in a formula are obtained by second-order approximation and an experiment. The device comprises a linear motor, a displacement sensor, a signal processor, a driving circuit and the like, wherein a control signal of the signal processor is connected to the driving circuit; the signal processor comprises a central processing unit, an A/D (Analog to Digital) circuit, a D/A (Digital to Analog) circuit, an ROM (Read Only Memory) module, an RAM (Random Access Memory) module, a pulse width modulation module and a signal receiving circuit, and is used for storing a formula and parameters of a sliding mode control method; and the central processing unit is used for obtaining a voltage signal of the mover coil according to the mover displacement data of the displacement sensor and regulating the voltage of the mover coil through the pulse width modulation module so as to realize stable linear movement of the mover. By adopting the method and the device, system buffeting is eliminated effectively, and the running reliability is enhanced; and the method and the device are easy to realize.

The invention discloses an anti-saturation boundary control method for a marine flexible riser system. Based on the Lyapunov theory and a back-stepping method, a smooth hyperbolic tangent function, anauxiliary system and a Nussbaum function are introduced to establish a boundary control rate of the marine flexible riser system. The control parameters in the boundary control rate are obtained through pre-training, and then the partial derivatives of the three parameters at the moment t are obtained through calculation of historical data according to the actually-measured shear force, inclination and displacement of the top of a riser, finally, the boundary control rate at the moment t is calculated based on the obtained actual parameters, and a driving device applies an acting force to thetop of the riser according to the boundary control rate. The invention further discloses an anti-saturation boundary control device for a marine flexible riser system, a storage medium and a server.The method and the device can solve the problem of tremor caused by using a sign function to limit the control input, can effectively control the vibration of the flexible riser, and are few in measurement parameters and easy to implement.

The invention discloses an identification method for beam structure damage of vibration mode weighing modal flexibility. The method comprises the following steps: obtaining frequency and the vibration mode of the beam structure before and after the damage through a modal test; calculating vibration mode curvature sign function weighing damage index based on the frequency and the vibration mode before and after the damage to locate the damaged structure, calculating a beam structure node damage degree according to a relative change of the vibration mode curvature sign function weighing damage index before and after the damage, and then calculating a unit damage degree. The identification method for the beam structure damage of the vibration mode weighing modal flexibility can effectively determine a damage location of a single-damage and multi-damage working condition for the beam structure, the calculation method of the damage degree of the corresponding index under a statically determinate structure and a statically indeterminate structure can be used to identify the damage degree accurately, the shortcomings that the existing modal flexibility curvature index cannot be used to identify the damage degree are overcome, and the method can be applied to the nondestructive testing and damage degree assessment of the beam structure.

The invention discloses a vehicle sideslip angle estimation method based on a second-order sliding-mode observer and belongs to the field of vehicle control. The vehicle sideslip angle estimation method comprises steps as follows: step 1, a vehicle state is detected by a sensor, and specifically, the velocity vx of a running longitudinal wheel of the vehicle is detected by a velocity sensor; the yaw velocity omega in the vehicle running process is detected by a yaw velocity sensor; a front wheel rotating angle delta in the vehicle running process is detected by a steering wheel angle sensor; step 2, the second-order sliding-mode observer is designed, the step 2 comprises a step 2.1 and a step 2.2, in the step 2.1, a kinetic model of a vehicle system is established firstly, and in the step 2.2, the second-order sliding-mode observer is designed according to the kinetic model of the vehicle; step 3, the information about the vehicle state detected in the step 1 is transmitted to the second-order sliding-mode observer designed in the step 2, and a sideslip angle is obtained through operation estimation. A two-degree-of-freedom kinetic model of the vehicle is used, the designed observer has a fractional power item, the steady-state error can be reduced, the observer has a sign function item, and the robustness of the system can be improved.

The invention discloses a method and system for generating an electronic case history with informing and signing functions. The method comprises the following steps of: collecting a voice file and a medical image file during diagnosis of a doctor on a patient; transmitting the voice file and the medical image file to a server; resolving the received voice file by the server to obtain a voice resolving result, and resolving the received medical image file by the server to obtain a medical image resolving result; converting the voice resolving result and the medical image resolving result into text files; comparing the converted text files with pre-stored medical terms; performing medical term error correction to form an electronic case history file; storing the electronic case history file; configuring the corresponding relationship between the formed electronic case history and a client of the patient or a family member of the patient; marking the time of an event in the electronic case history to form a timestamp; sending an informing and signing notice to the client of the patient or the family member of the patient corresponding to the electronic case history file; receiving the informing and signing notice by the client of the patient or the family member of the patient; and storing notice receiving feedback information into the electronic case history file.

The invention belongs to the technical field of autonomous underwater robot propeller fault tolerance, in particular to an autonomous underwater robot propeller fault-tolerant control method based ona sliding mode algorithm and thrust secondary adjustment; a sign function is replaced by a bipolar function, so that the self-adaptive adjustment of switching gain and the thickness of a boundary layer is realized, and a buffeting phenomenon of the slip-mode fault-tolerant control is weakened; a fault-tolerant control method combining sliding mode control and thrust secondary adjustment is adopted, so that the weight coefficient of a fault thruster in a propeller priority matrix changes along with the change of the fault degree, and the control voltage of the fault thruster is reduced; and a corresponding control compensation value is added into the control law to eliminate the influence of the deviation, and the purpose of fault-tolerant control is achieved. The problem of buffeting caused by the introduction of the sign function in sliding mode control of the autonomous underwater robot is solved, and the fault information provided by the fault diagnosis system is combined, so that the use level of the fault propeller is reduced, and the influence of the propeller faults on the system tracking performance is reduced.

The invention provides a dynamic sliding mode attitude tracking control method and system for a flexible spacecraft. The method comprises the steps of S1, establishing error posture quaternion-based kinematic equation and kinetic equation of the flexible spacecraft; and S2, by introducing a dynamic switching function, designing a dynamic sliding mode attitude tracking control law of the attitude tracking problem of the flexible spacecraft, and designing a finite time convergence-based robust differentiator to estimate a partial state of a flexible spacecraft system. The dynamic sliding mode attitude tracking control method and system has the beneficial effects that the problem of buffeting caused by a traditional sliding mode control law symbol function is effectively inhibited through thedesign of the switching function; and the dynamic sliding mode attitude tracking control method can enable the spacecraft system to carry out attitude tracking.

The invention relates to a selective visual attention computation model based on pulse cosine transform. The model gives a input image M, whose saliency map computation steps are as follows: the formula (1) P=sign (C(M)), the formula (2) F=abs(C(P)), formula (2) SM=G*F, C and C respectively represent discrete cosine transform and inverse transform thereof, sign(.) is a sign function, and abs(.) is an absolute value function, G is a two-dimension gauss low-pass filter, wherein, only the DCT coefficient sign is reserved in formula (1), and the amplitude information is discarded; the dual factor (that is -1 and 1) simulates electric discharge of human brain neurons or not; the formula (1) is called pulse cosine transform (PCT), and the method is a called computation saliency map model, at last, the saliency map is obtained by computing formula (1) and formula (2). This method model has the advantages of simple structure, low operand, extensive application prospects in the fields of robot navigation, virtual human system, automatic focusing system and other computer visions.

A PMSM sensorless control method based on an improved sliding mode observer is disclosed. The sigmoid function with variable boundary layer thickness is used to replace the sign function, The back-EMFobserver is constructed to separate the back-EMF signal, which eliminates the low-pass filter and phase compensation. The observer gain can be adjusted dynamically with the speed, and the chatteringphenomenon of the sliding-mode observer can be restrained effectively and the ideal observation precision in the wide speed range can be obtained. The on-line identification of stator resistance and torque observation are added to the improved sliding mode observer, which improves the robustness of the system to internal and external parameter changes.

The invention relates to a face search method and system. The method includes the following steps that: a network framework for face retrieval is constructed, and the network framework is optimized; parameters in the network framework are adjusted according to a reverse propagation mode; training sample pictures are inputted into the adjusted network framework, so that test cases can be generated; quantization calculation is performed on the test cases according to a sign function, so that the binary codes of the test cases are obtained, and Hamming distances between the training sample pictures are calculated through the binary codes; and the approximation degrees of the training samples are sequenced according to the Hamming distances, and therefore, the training of the network framework for face retrieval is completed; and face pictures to be retrieved are inputted into the trained network framework for face retrieval, so that the face pictures to be retrieved can be retrieved, and the approximation degree-sequenced face pictures to be retrieved can be obtained. According to the face search method and system of the invention, the network and outputted features are optimized from the above aspects, so that the same accuracy can be maintained under a large-scale face database or the retrieval of face images can be performed quickly with accuracy decreased in a range as small as possible.

The invention discloses a deep non-relaxation Hash image retrieval method based on point pair similarity. The method comprises the following steps: dividing a data set of an image into a training sample set Dtrain and a test sample set Dtest according to a ratio of 5: 1; constructing a deep convolutional network architecture; training the convolutional neural network by using the training sample set and taking the training data set image and the category label thereof as the input of the neural network to obtain and store a model of the deep neural network; and removing a dropout layer of theconvolutional neural network model according to the convolutional neural network model, and adding a symbol function to the output end of the network; inputting the training sample set Dtrain and theDtest into the model to obtain a Hash code Btrain of the training sample set and a Hash code Btest of the test sample set; and taking the hash code of the test image from the test sample to obtain a vector corresponding to the Hamming distance; and sorting each numerical value of the Hamming distance vector in an ascending order to serve as a retrieval result. According to the method, the problemthat a large number of errors are generated in the process of quantizing the binary hash code through the hash function is effectively solved, and the image retrieval accuracy is improved.

The invention discloses a multispiral chaos generator, comprising an integrator N0, a generator N1 of three sectionally linear odd functions each with an adjustable turning point value alpha, nine symbol functions generator, a linear function generator N3 and seven switchers K1, K2, K10, K11, K12, K13 and K14; as the switcher K2 is closed and K1 opened, using N0, N2 and N3 and the switching of K10, K11, K12, K13 and K14 to be able to separately generate eight different multispiral chaos absorbers together: three-spiral, four-spiral, five-spiral, six-spiral, seven-spiral, eight-spiral, nine-spiral and ten-spiral ones; as K1 closed and K2 opened, using N0 and N1 to generate four different unispiral and double-spiral chaos absorbers: double-layer unispiral, single- layer unispiral, double-layer double-spiral and single-layer double-spiral ones.

The invention discloses a synthesis method of a multifrequency synchronous signal source, comprising the following steps of, determining an amount N of main frequencies in a multifrequency synchronous signal to be synthesized, thereby determining that the signal is subdivided into 2N equal parts within a period T0, wherein N should be an odd number; finding out vectors of first N symmetric odd functions SAL (20, t), SAL (21, t), ......, SAL (2N-1, t) in a Walsh function system within a period, wherein each vector contains 2N elements; summing N vectors to obtain a sum vector g (N, t); carrying out normalization treatment on the sum vector g (N, t) with a sign function sgn () pair, thereby obtaining vectors f (N, t) of multifrequency synchronous signals of +1 and -1 within the period T0; and repeating the f (N, t) with a fundamental frequency period T0 to obtain a periodic multifrequency synchronous signal. The multifrequency synchronous signal source synthesized through the method has various very ideal time domain and frequency domain characteristics and realizes multifrequency synchronous measurement of an impedance spectroscopy.

Provided is a flexible satellite adaptive neural network sliding mode attitude control method. The invention relates to a flexible satellite adaptive neural network sliding mode attitude control method. The invention provides a flexible satellite adaptive neural network sliding mode attitude control method to solve the problem that the attitude of a flexible satellite fluctuates due to modal vibration of a panel and rotation of an antenna and the reduction of system stability is caused thereby. The method comprises the following steps: step 1, establishing a flexible satellite attitude dynamics model; step 2, obtaining a simplified flexible satellite attitude dynamics equation; step 3, designing a sliding mode attitude controller with use of an RBF neural network according to the simplified flexible satellite attitude dynamics equation; and step 4, further using an RBF neural network approximation sign function eta'sgn(s) to weaken the influence of buffeting to the sliding mode attitude controller so as to obtain a buffeting-weakened sliding mode attitude controller. The flexible satellite adaptive neural network sliding mode attitude control method of the invention is applied to the field of flexible satellite attitude control.

A method for control that yaw of a vehicle on an expected path belongs to the control field of an unmanned vehicle. In order to solve the problem of the yaw control of the vehicle on the expected path, the main points are as follows: S2. The equivalent sliding film pendulum torque controller is established based on the vehicle dynamics model. The effect is that the pendulum torque controller is established based on the quasi-sliding film control, and the hyperbolic tangent function is used to replace the sign function, which effectively reduces the chattering phenomenon of the quasi-sliding film control.