The structural asymmetry of the MEMS rate-integrating gyro (RIG) mode produces a threshold and an angle-dependent bias (ADB) that cause gyroscopes operating in this mode to stop working at input rates below the threshold and degrade the linearity of the output angle. This defect in the RIG output angle is actually caused by a precession angular-rate bias that results from both damping asymmetry (anisodamping) and stiffness asymmetry (anisostiffness). This paper describes a novel compensation method based on Fourier series fitting combined with a multiple iteration technique. The proposed compensation method can significantly reduce both the input rate threshold and ADB. Simulations indicate that the threshold and ADB caused by anisodamping and anisostiffness can be reduced by three orders of magnitude. An experimental application of this method produced a MEMS RIG threshold as low as 0.05° per second, representing an improvement of two orders of magnitude and lower than has previously been reported. INDEX TERMS MEMS rate-integrating gyro, Asymmetric damping, Asymmetric stiffness, Threshold.

Devices used to set and control the environmental temperature are critical to the performance of gas-sensitive material analyzers, which use silicon microcantilevers to characterize the gas-sensitive materials. This paper describes a novel microtemperature-control device that uses a double Peltier structure to replace the traditional refrigerant temperature control system. A proportional-integral-derivative (PID) algorithm is used to achieve accurate and fast temperature control, with a long short-term memory (LSTM) network trained to identify the nonlinear dynamics of the Peltier system. A neighbor hybrid mean center opposition-based learning particle swarm optimization (NHCOPSO) algorithm is proposed to optimize the PID controller. The LSTM network identification is obviously better than that of previous Peltier system identification methods, and the NHCOPSO algorithm is found to be superior to other improved PSO and evolutionary algorithms on benchmark functions and in PID parameter optimization. Experimental results show that the proposed temperature control device greatly improves the accuracy and efficiency of gas-sensitive material analysis with a temperature control range of −40 to 180 • C, a temperature control tolerance within ±0.05 • C, a maximum heating rate of 20 • C/min, and a maximum cooling rate of −10 • C/min. INDEX TERMS Gas-sensing material analysis, intelligent system identification, long short-term memory, particle swarm optimization, Peltier temperature control system.

This paper describes a novel rate and rate-integrating mode-switchable axisymmetric gyroscope. A precession angle tracking algorithm is developed to enable the gyro to switch automatically between rate and rate-integrating modes at preset rate points through a digital control system within the gyro. We also propose a vibrating amplitude control method for the rate-integrating mode that directly extracts the angular rate output to ensure switching stability. In rate mode, the bias instability and angle random walk of the gyro reach 0.106°/h and 0.011°/√h, respectively. Additionally, an input range of over ±5000°/s is measured in rate-integrating mode. The scale factor nonlinearity reaches approximately 116 ppm over the full-scale range. The control system implements effective steering control of the gyroscope, with a switching delay of 10 ms from rate mode to rate-integrating mode and 100 ms from rate-integrating to rate mode. The proposed system actualizes a new type of gyroscope with high accuracy and a wide input range, which combines the benefits of rate and rate-integrating modes.