相对重力仪高稳定性恒温系统的设计与实现  

Design and implementation of high stability constant temperature system for relative gravimeter

作　　者：王智奇[1] 吴宗坤 杨晔[1] 宋丽薇[1] 朱学毅[1] WANG Zhiqi;WU Zongkun;YANG Ye;SONG Liwei;ZHU Xueyi(Tianjin Navigation Instrument Research Institute,Tianjin 300131,China)

机构地区：[1]天津航海仪器研究所,天津300131

出　　处：《传感器与微系统》2022年第5期80-83,共4页Transducer and Microsystem Technologies

基　　金：天津市重大专项科技项目(19ZXJRGX00030)。

摘　　要：自研国产便携式相对重力仪的重力测量精度指标要求优于20×10^(-8) m/s^(2),而其零长弹簧重力敏感器因存在不可消除的温度效应影响,要求工作点的温度变化幅度不可超过0.001℃才能满足实际测量需求。为此,必须研究重力仪的温度特性,并研制高精度温控系统。针对弹簧式重力敏感器,从重力仪的热结构、温控电路和控制算法等方面进行分析与研究,设计和实现一种两级三路高稳定性恒温控制系统。该系统以比率桥式电路实现高精度测温,设计数字分段式Smith-PID预估复合控制律,通过内高外低的温度梯度控制,使重力敏感器处于设定的恒温环境中。经试验考核表明:在同一恒温热结构下,Smith-PID预估复合控制律实现的控制效益优于常规PID控制律。在Smith-PID预估复合控制律作用下,外界环境温度为室温时,重力敏感器所处的内部工作点的温度稳定性优于0.0005℃;外界环境温度为-20~+45℃交替变温时,该内部工作点的温度稳定性优于0.001℃。Requirement of gravity measurement precision index of self-developed domestic portable relative gravity meter is prior to 20×10^(-8) m/s^(2),due to the ineligible temperature effect of its zero-length spring gravity sensor,the temperature change amplitude at the working point is not to exceed 0.001℃,which can meet the actual measurement needs.For this reason,it is necessary to study the temperature characteristics of the gravimeter and develop a high-precision temperature control system.Aiming at the spring-type gravity sensor,thermal structure,temperature control circuit and control algorithm of the gravimeter are deeply analyzed and studied,a two-stage and three-way high stability constant temperature control system are designed and implemented.The constant temperature control system uses the ratio bridge circuit method to achieve high-precision temperature measurement,adopts the segmented digital Smith-PID algorithm as the core control law,and makes the gravity sensor in an ideal constant temperature environment through the stepped temperature control of high inside and low outside.Tests show that under the same thermostatic thermal structure,Smith-PID estimates that the control benefits achieved by the composite control law are prior to those of conventional PID control laws.Under the action of Smith-PID estimated composite control law,when the ambient temperature is room temperature,the temperature stability of the internal environment where the gravity sensor is located prior to 0.0005℃;under the variable temperature conditions of-20~+45℃,the temperature stability of the internal environment is prior to 0.001℃.

关 键 词：相对重力仪 弹簧式重力敏感器 恒温控制 比率桥式电路 分段式Smith-PID 

分 类 号：TP212[自动化与计算机技术—检测技术与自动化装置] TH762[自动化与计算机技术—控制科学与工程]