Research On Key Technology Of Distance Measurement System Based On Ultrasonic Sensor

Ultrasonic ranging is a method of ranging that is unaffected by the detection environment and that does not require contact.It can accurately measure distances in both dark and vulnerable environments.Moreover,the ultrasonic wave has strong directionality,which is beneficial to echo detection and recognition,so that ultrasonic ranging is widely used,especially for various electronic products such as automobile radar and sweeping robot,and these products have gradually become a necessity for people,and people higher requirements are placed on the high precision performance of these electronic devices.Therefore,this paper studies the key techniques of ultrasonic ranging system to improve the accuracy of ranging.The main research contents are as follows:1.This paper designs the overall architecture of the ultrasonic sensor ranging system.The circuit that receives the sensor and the transmitting sensor is integrated in the same system to form a transceiver-integrated sensor,and the common part of the two sensors is reduced in ease of integration and miniaturization.2.Push-pull inverter circuit and mid-cycle transformer are used for drive design,and the push-pull inverter circuit has a simple structure.The mid-cycle transformer has a boosting and frequency-selecting function,which is boosted by the turns ratio of the primary and secondary coils of the transformer,and the resonance is generated by using the equivalent inductance of the transformer and the equivalent capacitance of the sensor to perform frequency selection.In addition,the mid-cycle transformer can also achieve high-efficiency emissions by changing the number of turns of the secondary coil to match the equivalent impedance of the transducer.3.In the variable gain structure designed,the resistance of each resistor in the resistor network is specifically designed.The resistance feedback node is controlled by the digital signal input by the combination logic.By changing the signal,the feedback coefficient can be changed,and the gain can be changed according to the d B type gradient to realize high-precision design.4.In the designed power circuit architecture,high-voltage MOS and low-voltage MOS devices are used,and high-low voltage MOS series and gate-connected special differential input structures are used to achieve high and low voltage conversion and output stable voltage.Nested Miller compensation is used on the loop to increase the bandwidth and improve the stability of the circuit.5.Based on the 0.18?m BCD process,the external regulator of the linear regulator structure in this power supply has an output voltage of 3.3V at 25 V.At 4.3V and 40 V,the output voltages are 3.287 V and 3.315 V,respectively,and the amplitude deviations are0.39% and 0.45%,respectively,satisfying a wide range of inputs from 4.3V to 40 V.The sensor's drive current is increased by 13.5 m A gradient and is adjustable from 111.2 m A to311.3 m A to achieve programmable design.The gain of the preamplifier of the variable gain amplifier reaches 35 d B.On this basis,the gain is increased by 0.7d B gradient and adjustable within the range of 45 d B~55d B,which satisfies the design of high precision ranging circuit.