Abstract: A displacement measurement system of heterodyne grating interferometer, comprises a reading head, a measurement grating and an electronic signal processing component. Laser light emitted from the laser tube is collimated, passes through the first polarization spectroscope, and then emits two light beams with a vertical polarization direction and a vertical propagation direction; the two light beams pass through two acousto-optic modulators and respectively generate two first-order diffraction light beams with different frequencies, which are later divided into reference light and measurement light; two parallel reference light beams form a beat frequency electric signal with positive and negative first-order diffraction measurement light respectively after passing through a measurement signal photo-electric conversion unit; the beat frequency signals are transmitted to the electronic signal processing component for signal processing, thus the output of linear displacement in two directions is realized.

Abstract: A maglev working table with six degrees of freedom comprises a pedestal (800), a rotation drive apparatus, a planar-motion apparatus, an angle measuring apparatus (500), and a displacement measuring apparatus. The displacement measuring apparatus comprises four direct-current motors (600) and four displacement measuring apparatus PSD assemblies. Under the effect of the rotation drive apparatus, a planar-motion apparatus coil array stator (200) axially connected to a rotation drive apparatus circular permanent-magnet array mover (300) rotates, so that a phase difference is formed between a planar-motion apparatus permanent-magnet array mover (100) and the planar-motion apparatus coil array stator, and then the maglev working table mover, namely, the planar-motion apparatus permanent-magnet array mover rotates at 360° in the horizontal plane.

Abstract: A method for measuring displacement of a large-range moving platform, comprising: arranging multiple beams of first measuring light parallel to one another and generated by an optical path distribution device and a position sensitive detector array in a certain manner, to ensure that at least one beam of first measuring light is detected by the position sensitive detector array when a moving platform is at any position of a moving area; a detection head array capable of determining whether a light beam is shaded being used for auxiliary measurement of a position of the moving platform; and determining a position of the moving platform that corresponds to the first measuring light measured by the position sensitive detector array, to calculate displacement of the moving platform. The method effectively enlarges a measurement range of the position sensitive detector array, and implements measurement of long range displacement of the moving platform.

Abstract: A silicon wafer platform with anti-collision function comprises a silicon wafer platform body (1) and a cable platform (2). The cable platform (2) is mounted on one side of the silicon wafer platform. The silicon wafer platform comprises three airbags (3), four damping buffer elements (4) and an air source (6), the three airbags (3) being connected in series and respectively secured on the other three sides of the silicon wafer platform by an airbag support (5), two adjacent airbags (3) communicating with a gas pipeline by one damping buffer element (4), and the gas pipeline being secured on the cable platform (2) and communicating with the air source. When two silicon platforms collide, the collision is buffered by the airbags and the silicon wafer platforms are not bounced off.

Abstract: A dual-frequency grating interferometer displacement measurement system, comprises a dual-frequency laser, an interferometer, a measurement grating and an electronic signal processing component. The measurement system realizes displacement measurement based on grating diffraction, optical Doppler effect and optical beat frequency theory. Dual-frequency laser light is emitted from the dual-frequency laser and split into reference light and measurement light via a polarization spectroscope. The measurement light is incident to the measurement grating to generate positive and negative first-order diffraction. The diffraction light and the reference light form a beat frequency signal containing displacement information about two directions at a photo-detection unit, and linear displacement output is realized after signal processing.

Abstract: A method for measuring the displacement of a planar motor rotor. The measuring method comprises: four magnetic induction intensity sensors are distributed on the planar motor rotor; sampled signals of the four distributed sensors are processed to obtain signals Bsx, Bcx, Bsy and Bcy and magnetic field reference values Bksx, Bkcx, Bksy and Bkcy; and X-direction displacement and Y-direction displacement can be measured respectively according to inequalities (I) and (II) by judgments, wherein ?x and ?y are X-direction displacement resolution and Y-direction displacement resolution respectively, and BM is the magnetic induction intensity amplitude of the magnetic field of said planar motor. The method provided by the invention is simple in calculation, can avoid calculation of a transcendental function and solve the quadrant judgment problem, is favorable to real-time high-speed operation and has a high engineering value.

Abstract: A method for measuring displacement of a large-range moving platform, comprising: arranging multiple beams of first measuring light parallel to one another and generated by an optical path distribution device and a position sensitive detector array in a certain manner, to ensure that at least one beam of first measuring light is detected by the position sensitive detector array when a moving platform is at any position of a moving area; a detection head array capable of determining whether a light beam is shaded being used for auxiliary measurement of a position of the moving platform; and determining a position of the moving platform that corresponds to the first measuring light measured by the position sensitive detector array, to calculate displacement of the moving platform. The method effectively enlarges a measurement range of the position sensitive detector array, and implements measurement of long range displacement of the moving platform.

Abstract: A single degree of freedom vibration isolating device of a linear motor and a motion control method thereof. The vibration isolating device comprises a balance block, an anti-drifting driving unit, and a control unit. An upper surface of the balance block is connected to a stator of the linear motor, and a lower surface of the balance block is connected to a base. The anti-drifting driving unit is connected to the balance block for controlling the position of the balance block. Provided two motion control methods; inputting a second grating ruler signal to the control unit as feedback to perform variable stiffness and nonlinear control on the balance block; inputting a first and a second grating ruler signal to the control unit as feedback to obtain resultant centroid displacement signals of the rotor and the balance block to perform nonlinear anti-drifting control on the balance block.

Abstract: A two-dimensional, position-sensitive sensor-based system for positioning an object having six degrees of freedom in space, used for positioning of a silicon table and mask table of a lithography machine. The system comprises mainly a semiconductor laser 1, an optical fiber collimator 2, optical fibers 3, 7, 10, and 13, an optical fiber splitter 4, filter plates 6, 9, and 12, three PSD sensors 5, 8, and 11, and a signal processing system. Laser emitted by the semiconductor laser 1 is irradiated onto the optical fiber collimator 2, then transmitted respectively via three paths, and received by the PSD sensors 5, 8, and 11 after having background light filtered out by the filter plates 6, 9, and 12, while the positions of laser spots on the three PSD sensors 5, 8, and 11 are processed by the signal processing system to acquire the position and orientation.

Abstract: A planar motor rotor displacement measuring device and its measuring method are provided. The motor is a moving-coil type planar motor. The device comprises probes, two sets of sine sensors, two sets of cosine sensors, a signal lead wire and a signal processing circuit. The method is arranging two sets of magnetic flux density sensors within a magnetic field pitch ? along two vertical movement directions in the rotor located in the sine magnetic field area. Sampled signals of the four sets of sensors are respectively processed with a frequency multiplication operation, four subdivision signals are obtained, the zero-crossing points of the four subdivision signals are detected, and then two sets of orthogonal pulse signals are generated. The pulse number of the orthogonal pulse signals is counted, and phase difference of the two sets of orthogonal pulse signals is respectively detected.

Abstract: A two-dimensional, position-sensitive sensor-based system for positioning an object having six degrees of freedom in space, used for positioning of a silicon table and mask table of a lithography machine. The system comprises mainly a semiconductor laser 1, an optical fiber collimator 2, optical fibers 3, 7, 10, and 13, an optical fiber splitter 4, filter plates 6, 9, and 12, three PSD sensors 5, 8, and 11, and a signal processing system. Laser emitted by the semiconductor laser 1 is irradiated onto the optical fiber collimator 2, then transmitted respectively via three paths, and received by the PSD sensors 5, 8, and 11 after having background light filtered out by the filter plates 6, 9, and 12, while the positions of laser spots on the three PSD sensors 5, 8, and 11 are processed by the signal processing system to acquire the position and orientation.