Absolute Linear Time Grating Displacement Sensor Based On Orthogonal Double Traveling Wave Magnetic Field

With the rapid development of national economy,high precision machining has an important impact on the level of industrial development in China.As the important position feedback unit,displacement sensor plays an important role in various medium-high machine tool systems.Absolute displacement sensor has the advantages of strong anti-interference ability,high performance,no need to find zero reference points,and elimination of accumulated errors.It is widely used in industrial production.Absolute grating,magnetic grating,capacitive grating and other grating displacement sensors improve measurement accuracy and resolution by using ultra-precision lines in space.Ultra-precision lines require extremely high machining environment and equipment,so the cost is high.Establishment of double coordinate system for time-grating displacement sensor and measurement of the spatial displacement using the time.Time grating displacement sensor has the advantages of low cost,high data reliability and strong anti-jamming ability.At present,incremental method is the main method to measure displacement of time grating sensor.Once there are errors in the measurement process,errors will be accumulated,and most absolute measurement methods are angular displacement measurement,absolute linear time grating measurement research still needs to be carried out continuously.Based on the current situation,an absolute linear time grating sensor based on orthogonal double traveling wave magnetic field is studied in this paper.The main contents are as follows:(1)Analyzing the absolute measurement methods of several kinds of displacement sensors,combining with the principle of time grating measurement,the realization method of this subject is proposed.(2)Study the measurement structure of the sensor,design and analyze the process of generating two sets of orthogonal traveling wave magnetic field by two space orthogonal excitation coils driven by alternating current signal,and decoupling the electric signal into displacement information by the induction coil in the magnetic field,which proves the feasibility of the absolute displacement sensor in theory.(3)The model of absolute linear time grating displacement sensor is established and simulated according to the sensor structure.The basic parameters such as coil coupling magnetic flux are quantitatively analyzed by MATLAB software,and the simulation results are in agreement with the theory.The electromagnetic fieldsimulation software MAXWELL verifies that the absolute displacement of the sensor and the phase difference between the two signals satisfy the corresponding relationship of the sensor,and verifies that the absolute position of the sensor can be realized.Shift measurement.(4)According to the structure design of the sensor,the sensor object is made.The design and implementation of software system and hardware system are carried out,and the experimental platform is built to provide conditions for sensor function testing.The excitation signal,induction signal and traveling wave signal are tested,and the accuracy of the sensor is tested.The error curve is analyzed and corrected according to the error law.Experiments show that the sensor can realize absolute displacement measurement,and the measurement accuracy of the sensor prototype is +12 micron in the range of 0-80 mm.It has the advantages of low cost,adaptability to oil pollution and dust,good stability and so on.