179results about How to "High stability and precision" patented technology

The present invention provides a current sensor capable of detecting a current magnetic field generated by a current to be detected with high precision and stability while realizing a compact configuration. The current sensor has: first and second magnetoresistive elements each including a pinned layer having a magnetization direction pinned in a predetermined direction, a free layer whose magnetization direction changes according to applied magnetic fields, and an intermediate layer sandwiched between the pinned layer and the free layer; and first and second permanent magnets for applying bias magnetic fields to the first and second magnetoresistive elements. The bias magnetic field has a parallel component parallel to a magnetization direction under no magnetic field and an orthogonal component orthogonal to the parallel component. Consequently, uniaxial anisotropy of the free layer can be enhanced without using shape anisotropy. Therefore, the current magnetic field to be detected can be detected with high precision and stability irrespective of the shapes of the magnetoresistive elements, and the invention is favorable for miniaturization.

The present invention provides a current sensor of smaller and simpler configuration, capable of measuring a current to be detected with high precision and stability. A current sensor has a V-shaped conductor line and a pair of magnetoresistive elements disposed along with the conductor line so that a resistance value of one of the magnetoresistive elements changes in a direction opposite to that of resistance-value-change of the other magnetoresistive element according to current magnetic fields produced by a current to be detected flowing through the conductor line.

A current sensor capable of detecting current magnetic fields generated by a current to be detected with high precision and stability while realizing a compact configuration is provided. The current sensor includes: a conductor generating a current magnetic field in accordance with supplied current to be detected; a magnetoresistive element including a free layer having a magnetization direction that varies in accordance with the current magnetic field, a pinned layer having the magnetization direction that is pinned to a direction orthogonal to the magnetization direction of the free layer under no current magnetic field, and an intermediate layer provided between the free layer and the pinned layer; and a bias applying means for applying, to the magnetoresistive element, a bias magnetic field along a direction same with the magnetization direction of the free layer under no current magnetic field.

A current sensor includes a conductor line, and a magnetic sensor in which resistance value changes according to a current magnetic field produced by a current to be detected flowing through the conductor line. The conductor line includes: a pair of parallel portions each having a same and uniform cross-sectional area, while extending in parallel with each other separated at a first distance therebetween; a connecting portion connecting one end of one of the parallel portions and one end of the other of the parallel portions; and a pair of terminal portions each connected to the other end of each of the parallel portions, while extending to face with each other separated at a second distance therebetween, the second distance being wider than the first distance, the terminal portions each having a larger cross-sectional area than that of each of the parallel portions.

The invention relates to an aerophotography gyrostabilized platform with three freedom degrees and large load, comprising a platform body, a driving system, an inertia measurement unit, a relative turn angle measuring unit of a ring rack of the platform body, a high-frequency line vibration isolating unit and a platform control system, wherein the inertia measurement unit and the relative turn angle measuring unit of the ring rack of the platform body monitor the information of the angular movement of the platform body caused by the angular movement of the body of an airplane; the platform control system works out a control instruction applied by a relatively determined coordinate system of the platform when being stabilized relative to the driving system at real time according to the monitored information of the angular movement of the platform body by a certain control algorithm; the driving system drives the platform body according to the control instruction to rotate so as to realize the isolation of the angular movement of the body of the airplane; and the high-frequency line vibration isolating unit realizes the isolation of the high-frequency line vibration of the body of the airplane. The aerophotography gyrostabilized platform with three freedom degrees and large load effectively isolates the angular movement and the high-frequency line vibration of the body of the airplane and enhances the stability of a visual axis of an aerial photography camera, and the cost is cheaper.

The present invention is directed to the provision of a wavelength division multiplexing optical transmission apparatus and, more particularly, to a wavelength division multiplexing optical transmission apparatus having high wavelength stability unaffected by the temperature characteristics, aging, etc. of an arrayed-waveguide grating (AWG) and its peripheral components. The wavelength division multiplexing optical transmission apparatus comprises: an arrayed-waveguide grating 10 having operating input/output ports and an input dummy port; a light emitting means 21 for generating a pilot signal to be input to the input dummy port; a light detecting means 22 for monitoring the pilot signal contained in a wavelength division multiplexed signal output from the operating output port; and a temperature control circuit 11 for controlling the temperature of the arrayed-waveguide grating in such a manner as to cancel the amount of wavelength fluctuation occurring in the arrayed-waveguide grating and detected by monitoring the pilot signal.

The invention discloses a method for estimating and compensating a coupling torque of an aerial remote sensing inertially stabilized platform. The method comprises the steps of: establishing a triaxial inertially stabilized platform dynamical model, estimating the coupling torque between a base and a framework according to information detected in real time by a POS (Polar Orbit Satellite), a roll/pitch gyroscope and an azimuth coded disc, then calculating a required torque motor current value for offsetting the coupling torque, and compensating the current value into a current given input value of a current loop, thus enabling a motor to output a torque which is equal to the coupling torque in magnitude and opposite in direction, compensating the coupling torque disturbance of the platform and improving the stability precision of the platform. By virtue of the method, the coupling torque is estimated and compensated in real time and the stability precision is improved; and the method is applicable to the aerial remote sensing inertially stabilized platform with the coupling torque between the base and the framework.

The invention discloses a three-way irrotational displacement absorber, which is applied to the vibration absorbing platforms of vehicle-mounted, ship-mounted and airplane-mounted photoelectric devices. The absorber comprises a baseplate component, a rocker component and an adapter plate component, wherein, the baseplate component is connected with a carrier and the adapter plate component is connected with load; and the rocker component is a rectangle frame which is formed by two groups of hinged rockers and two cylinder rods, and four vertexes thereof are hinged with four corners of the adapter plate in a sliding manner. When the adapter plate is applied with any acting force, the rocker component can only drive the adapter plate to move horizontally in X and Y directions but not rotate; the four vertexes of the rocker component are hinged with a pair of sliding auxiliary seats and a pair of fixed rotating auxiliary seats of the baseplate component so as to drive the adapter plate component to move horizontally in a Z direction but not rotate; and meanwhile the adapter plate component is connected with four three-way absorbers in the baseplate component so as to reduce the vibration in three directions. The three-way irrotational displacement absorber solves the problem that angular displacement is randomly caused in case of vibration disturbance for the vibration absorbing platform and provides technical support for improving the steady precision of the photoelectric load.

The invention discloses an optical axis inertia stability datum reference device which comprises a base, a moveable connecting part, a stable platform unit, an adjusting unit, a control unit and a reference light source, wherein the stable platform unit is connected with the other end of the moveable connecting part, is capable of being moved relative to the base, and is provided with a stable platform and an inertia sensation component which is fixedly mounted with the stable platform; the adjusting unit is mounted on the base and is used for adjusting a real-time position of the stable platform relative to the base; the input end of the control unit is connected with the inertia sensation component; the output end of the control unit is connected with the adjusting unit and is used for receiving an inertia sensation signal transmitted from the inertia sensation component, used for carrying out processing calculation on the inertia sensation signal, and used for outputting a control signal to the adjusting unit to enable the adjusting unit to carry out adjustment; the reference light source is fixedly mounted on the stable platform; the inertia sensation component is capable of measuring angle velocities of at least two spatial freedom degrees of the stable platform and a posture variations of the stable platform; correspondingly, the inertia sensation signal comprises the angle velocities of at least two spatial freedom degrees of the stable platform and the posture variations of the stable platform.

The invention relates to a photoelectric stable platform, which has a vibration-isolating inner ring and a plurality of frames. The photoelectric stable platform comprises an outer ring frame, an inner ring frame and an even number of vibration isolators of the same specifications, wherein various sensors are placed on the inner ring frame; and the vibration isolators are symmetrically installed relative to the centre of mass of the integration of the inner ring frame in which the various sensors which are installed. The invention has the advantages that: an isolation effect of the photoelectric stable platform on external interference is good; imaging quality and stabilization precision are high; the photoelectric stable platform is small in size, light in weight, large in bearing capacity, and convenient for assembly and disassembly; the weight of the platform can be reduced effectively; the assembly of the photoelectric stable platform can be adjusted quickly and conveniently according to requirements; and the photoelectric stable platform is characterized by simple structure, wide application range and the like.

The invention provides a double-speed-ring control method of an aerial remote sensing inertial-stabilized platform. The method utilizes the advantages of cascade control and adopts a double-speed-ring compound control scheme in that an encoder is adopted to carry out digital speed measurement to form a speed inner ring and a rate gyroscope is adopted to form a speed outer ring aiming at the disadvantage that a single speed ring inhibits a disturbance torque in stable control of a visual axis; an inner interference resisting performance and a function of isolating outer interferences of a stable circuit are realized by separately designing, so that the stability precision of a system is improved. According to the double-speed-ring control method disclosed by the invention, an extra sensor is not needed and the compound control is formed by improving a control algorithm; the double-speed-ring control method has the characteristics of simple structure and convenience for realizing engineering.

The invention discloses a large-diameter precise light beam pointing device which comprises a base plate, a large-diameter reflecting mirror and a driving component, wherein the back side of the large-diameter reflecting mirror is supported on the base plate through a two-freedom-degree bearing; the driving component is mounted on the base plate; the driving end of the driving component is connected with the large-diameter reflecting mirror and can drive the large-diameter reflecting mirror to move in two free freedom degrees. Due to the adoption of the large-diameter precise light beam pointing device, the large-screen image stabilization application requirements can be met, the stabilization precision can be remarkably improved, and the processing and assembling process can be greatly simplified.

The invention discloses an uniformization aligning mark combination and an aligning method and an aligning system thereof. The uniformization aligning mark combination consists of a porous uniformization aligning mark arranged at the target composing component of a photoetching device aligning system and a single-pore uniformization aligning mark arranged at a probe composing component. The porous uniformization aligning mark consists of four transparent elements and a chromeplated shielding layer. The single-pore uniformization aligning mark consists of a transparent element and a chromeplated shielding layer. The method uses the single-pore uniformization aligning mark at the probe composing component and a probe device under the single-pore uniformization aligning mark to process twice two-dimensional aligning scanning to an image formed by the porous uniformization aligning mark at the target composing component, and radiation measure information and position measure information obtained by the two times of canning are integrated for an aligning signal processing, which obtains the position relation of a space image formed by the target composing component at a target composing component bearing table through a projection system relative to a probe composing component bearing table.

The invention discloses a gyroscope stabilized platform adaptive composite control method. A double-loop control structure controlled by a position loop and a stability ring collectively. The position loop adopts the proportion integration differentiation control mode. The stability ring adopts the adaptive fuzzy-proportion integration differentiation composite control mode. A self-adjustment factor is used to realize the online adjustment of the fuzzy control basic domain. A composite control adaptive factor is used to realize the composite of fuzzy control and proportion integration differentiation control. The gyroscope stabilized platform adaptive composite control method of the invention can be used to make the gyroscope stabilized platform has advantages of fast response, high servo accuracy and good anti-interference ability.

The invention discloses a virtual multi-closed loop-based disturbance measurement feedforward suppression method. The virtual multi-closed loop-based disturbance measurement feedforward suppression method is used for improving the disturbance suppression capability of a control system stable platform so as to meet the demand of a higher-accuracy stable control system. A virtual gyro is obtained bya method of integrating an accelerator and a position sensor, and a fiber gyro of the stable platform is substituted by the virtual gyro. On the basis that virtual multi-closed loop control is achieved by the virtual gyro, the substituted fiber gyro is arranged on a carrier rack and is used for measuring an external disturbance speed, and an ideal feedforward compensation controller is used for feedforwarding the external disturbance to a control loop so as to actively suppress the influence of disturbance. On the premise that the system stability is not completely affected, the load and space requirement of the stable platform is effectively reduced, the disturbance suppression capability of the system is effectively improved, so that the stable platform obtains higher stability accuracy.

The invention discloses a water surface floating platform with a stability control device. The water surface floating platform comprises a platform body, floating barrels, supporting arms, motors, propellers and a control module. The multiple floating barrels are evenly distributed on the periphery of the platform body and fixedly connected with the platform body through the supporting arms. The bottom of each floating barrel is provided with one propeller connected with the corresponding motor. The control module is arranged in the platform body. By the adoption of the floating barrels, the capacity for restraining wave disturbance of the floating barrels is good, a posture can be kept stable within a certain wave height range, and the stability accuracy is high. The whole size is small, the inflation type floating barrels are detachably connected with the platform body, and therefore equipment is more convenient to carry, transport and the like. A control panel is provided with a sensor, the stability accuracy of the platform is improved, meanwhile, the swinging angle of the platform can be measured, and a stable working environment is provided for a platform carrier.

The invention relates to an inertial stabilization platform unbalanced disturbance hibition method. According to the method, a feedforward controller and a disturbance observer are adopted, wherein the feedforward controller comprises the proportional loop so as to change the unbalanced disturbance of the platform into the compensation current and feedforward back to the platform circuit loop, and drive the motor to produce the control moment, wherein the sizes of the moment and the unbalanced disturbance are equal, and the directions of the moment and the unbalanced disturbance are opposite; and the disturbance observer comprises a low-pass filter and a platform nominal model, wherein the low-pass filter can concurrently provide functions of inhibition of the low frequency unbalanced disturbance and elimination of the influence of the high frequency noise. According to the present invention, the established unbalanced disturbance model is used, the feedforward and disturbance observer comprehesive control method is adopted to achieve the inhibition on the disturbance observer, the control method integratedly utilizes the advantages of the two methods feedforward and disturbance observer, the influence of the unbalanced disturbance pn the platform performance is reduced, the stability precision of the inertial stabilization platform is significantly improved, and the inertial stabilization platform unbalanced disturbance hibition method is simple and is easy to perform, and is suitable for inhibition on the inertial stabilization platform unbalanced disturbance.

The invention relates to a pod stabilized platform control method based on backlash estimation and compensation. The method includes the steps: measuring a backlash value when a motor-shaft-end driving gear is meshed with a frame-shaft-end driven gear of a pod stabilized platform; establishing a backlash non-linear model of a pod platform azimuth transmission gear according to the backlash value; establishing a frame servo system kinetic model according to the backlash non-linear model; according to the frame servo system kinetic model, selecting a Lyapunov function stepwise by recursion by utilizing a contragradience integral method, constructing a state feedback based controller, and calculating a current value of control input of a torque motor; inputting the current value to the torque motor to drive a frame to rotate to a corresponding position. By the technology, by real-time backlash estimation and compensation when the motor-shaft-end driving gear is meshed with the frame-shaft-end driven gear, platform stabilization precision is improved; the method is accurate in compensation, concise in compensation algorithm and easy to implement by programming in a DSP (digital signal processor).