A Temperature Control Method for Microaccelerometer Chips Based on Genetic Algorithm and Fuzzy PID Control.

Jiaxiao Chen,Weidong Fang,Xiang Xu,Jian Bai,Qianbo Lu,Yuan Yao

doi:10.3390/mi12121511

Abstract

External temperature changes can detrimentally affect the properties of a microaccelerometer, especially for high-precision accelerometers. Temperature control is the fundamental method to reduce the thermal effect on microaccelerometer chips, although high-performance control has remained elusive using the conventional proportional-integral-derivative (PID) control method. This paper proposes a modified approach based on a genetic algorithm and fuzzy PID, which yields a profound improvement compared with the typical PID method. A sandwiched microaccelerometer chip with a measurement resistor and a heating resistor on the substrate serves as the hardware object, and the transfer function is identified by a self-built measurement system. The initial parameters of the modified PID are obtained through the genetic algorithm, whereas a fuzzy strategy is implemented to enable real-time adjustment. According to the simulation results, the proposed temperature control method has the advantages of a fast response, short settling time, small overshoot, small steady-state error, and strong robustness. It outperforms the normal PID method and previously reported counterparts. This design method as well as the approach can be of practical use and applied to chip-level package structures.

Highlights

Accelerometers are widely used in various fields, such as inertial navigation and earthquake monitoring
micro-opto-electromechanical system (MOEMS) accelerometers based on a grating interferometric cavity have been verified to gain high sensitivity and resolution [4,5], but in practice, they are susceptible to external influences, in which temperature is one of the main sources of error [6]
Note that the temperature distribution of the microaccelerometer chip was usually higher than the ambient temperature in the steadystate case, because the heating and dissipation of the chip were in equilibrium, wherein the heat transfer rate is proportional to the temperature difference between the ambient temperature and the chip boundary

Summary

Introduction

Accelerometers are widely used in various fields, such as inertial navigation and earthquake monitoring. Microaccelerometers can be classified into micro-electromechanical system (MEMS) accelerometers and micro-opto-electromechanical system (MOEMS) accelerometers. MOEMS accelerometers combined with optical measurement technology incorporate anti-electromagnetic interference and higher sensitivity than MEMS accelerometers [2,3]. MOEMS accelerometers based on a grating interferometric cavity have been verified to gain high sensitivity and resolution [4,5], but in practice, they are susceptible to external influences, in which temperature is one of the main sources of error [6]. Microaccelerometers are usually made of silicon and other materials, whose expansion coefficients and elastic modulus are susceptible to ambient temperature changes [7,8]. The performance aspects of MOEMS accelerometers, such as resolution and stability, are more prone to ambient temperature drift because of their extremely high sensitivity. It is necessary to precisely control the temperature of the microaccelerometer chip to obtain a constant temperature condition and enhance the chip’s performance

Methods

Results

Conclusion