Gyroscopic Systems Research Articles

Constrained H∞ control of gyroscopic ship stabilization systems

We suggest a constrained [Formula: see text] control scheme for gyroscopic marine vehicle stabilization systems with output and control constraints. The [Formula: see text] performance is used to measure the roll angle reduction of the vessel relative to wave disturbances in regular beam seas. Time-domain constraints, representing requirements for precession angle of gyroscopes and for actuator saturation, are captured using the concept of reachable sets and state-space ellipsoids. A state feedback solution to the constrained [Formula: see text] stabilization control problem is proposed in the framework of linear matrix inequality optimization and multiobjective control. This approach can potentially achieve the best possible vessel comfort with respect to roll motion by allowing constrained variables free as long as they remain within given bounds. Analysis and simulation results for roll dynamics of the vessel coupled with the gyroscopic actuator control system show possible improvements on roll motion stabilization while respecting time-domain hard constraints.

Calibration, Compensation and Accuracy Analysis of Circular Grating Used in Single Gimbal Control Moment Gyroscope.

The accuracy of the circular grating is the key point for control precision of the single gimbal control moment gyroscope servo system used in civilian micro-agile satellites. Instead of using the multi reading heads to eliminate eccentricity errors, an algorithm compensation method based on a calibration experiment using a single reading head was proposed to realize a low-cost and high accuracy angular position measurement. Moreover, the traditional hardware compensation method using double reading heads was also developed for comparison. Firstly, the single gimbal control moment gyroscope system of satellites was introduced. Then, the errors caused by the installation of the reading head were studied and the mathematic models of these errors were developed. In order to construct the compensation function, a calibration experiment using the autocollimator and 24-sided prism was performed. Comparison of angle error compensation using the algorithm and hardware method was presented, and results showed that the algorithm compensation method proposed by this paper achieved the same accuracy level as the hardware method. Finally, the proposed method was further verified through a control system simulation.

Temperature drift modeling and compensation of micro-electro-mechanical system gyroscope based on improved support vector machine algorithms

This article suggested two methods to compensate for the temperature drift of the micro-electro-mechanical system gyroscopes, which are support vector machine method and C-means support vector machine. The output of X axis which was ranged from −40°C to 60°C based on the micro-electro-mechanical system gyroscope is reduced and analyzed in this article. The results showed the correctness of the two methods. The final results indicate that when the temperature is ranged from −40°C to 60°C, the factor of B is reduced from 0.424 [Formula: see text] to 0.02194 [Formula: see text], and when the temperature is ranged from 60°C to −40°C, the factor of B is reduced from 0.1056 [Formula: see text] to 0.0329 [Formula: see text], and the temperature drift trend and noise characteristics are improved clearly.

Ultra-low-noise TIA topology for MEMS gyroscope readout

This paper proposes a TIA topology that can be used in accelerometer and gyroscope systems. The proposed TIA topology considerably relaxes the trade-off among the transimpedance gain, bandwidth, and input referred current noise without increasing the power consumption. Furthermore, this paper presents a model for gyroscope microelectromechanical systems (MEMS) resonator that enables us, unlike prior works, to predict the resolution of the gyroscope system at the early stage of the design. In this model, the noise arising from driving loop blocks is compared with the noise of sense channel blocks. It has been illuminated that the noise of sense transimpedance amplifier (TIA) is the most influential in the resolution of the gyroscope system. To improve the resolution, the proposed TIA is employed in the sense channel of the gyroscope system. It enhances the resolution by about 57% compared with the conventional TIA employed in the sense channel. Measurement results of a discrete-element prototype also verify the performance improvement of the proposed TIA topology.

A Phase Self-Correction Method for Bias Temperature Drift Suppression of MEMS Gyroscopes

Phase error of the demodulation clock in the Coriolis vibratory gyroscope system allows the quadrature errors to leak into the sense channel and causes significant bias and temperature drift at the rate output. A phase self-correction method to suppress the temperature drift of the bias in gyroscopes is proposed. Through sweeping the demodulation clock phase and simultaneously monitoring the mechanical quadrature error output in gyroscopes, the optimal demodulation clock phase with minimum relatively phase shift is determined. Thus the bias influenced by the temperature and surroundings can be calibrated on-chip at start-up or when the environment changes drastically without the requirement of the complicated instruments. The proposed approach is validated by a silicon MEMS gyroscope with the natural frequency of 2.8[Formula: see text]kHz, which shows nearly 22 times improvement in the temperature sensitivity of the system bias, from 550[Formula: see text]mdeg/s/∘C down to 24.7[Formula: see text]mdeg/s/∘C.

Analysis of the vulnerability of MEMS tuning fork gyroscope during the gun launch

Micro-electromechanical systems (MEMS) gyroscope is fragile under mechanical impact. Especially, MEMS tuning fork gyroscope with movable structures, such as oscillating frames and folding beams, is susceptible to failure during the gun launch. However, the gyroscope usually presents better shock resistance in the shock test than in the ballistic environment. In this paper, the multiple high-frequency axial shocks and lateral shocks were studied to explain this phenomenon. A single-axis MEMS tuning fork gyroscope was used to analyze its behavior in response to the shock. First, theoretical analysis was performed regarding to the multiple high-frequency axial shocks and lateral shocks. Then the finite element analysis (FEA) was carried out to study the failure mode of the gyroscope under the typical shocks during the gun launch. The analysis results showed that the shocks with continuous oscillating acceleration had a significant amplification effect on the stress of the gyroscope structure. In addition, axial shocks can work with lateral shocks to cause severe stress on the weak positions of the gyroscope. Shock tests were carried out to simulate the in-bore ballistic environment, where the gyroscope experienced continuous oscillating acceleration. The experimental results showed that the critical acceleration of failure will be decreased when the gyroscope is in a state of continuous oscillations.

The Characteristics and Locking Process of Nonlinear MEMS Gyroscopes.

With the miniaturization of micro-electro-mechanical system (MEMS) gyroscopes, it is necessary to study their nonlinearity. The phase-frequency characteristics, which affect the start-up time, are crucial for guaranteeing the gyroscopes’ applicability. Nevertheless, although the amplitude-frequency (A-f) effect, one of the most obvious problems in nonlinearity, has been well studied, the phase response of nonlinear gyroscopes is rarely mentioned. In this work, an elaborate study on the characteristics and locking process of nonlinear MEMS gyroscopes is reported. We solved the dynamic equation using the harmonic balance method and simulated the phase-locked loop (PLL) actuation process with an iterative calculation method. It was shown that there existed an apparent overhanging and multi-valued phenomenon in both the amplitude–frequency and phase–frequency curves of nonlinear gyroscopes. Meanwhile, it was ascertained by our simulations that the locking time of PLL was retarded by the nonlinearity under certain conditions. Moreover, experiments demonstrating the effect of nonlinearity were aggravated by the high quality factor of the drive mode due to the instability of the vibration amplitude. A nonlinear PLL (NPLL) containing an integrator was designed to accelerate the locking process. The results show that the start-up time was reduced by an order of magnitude when the appropriate integral coefficient was used.

Gyroscopic Tensegrity Robots

Mechanics and control of innovative gyroscopic structural systems are detailed in the paper. By adding controllable spinning wheels to a network of controllable, axially loaded strings and bars, it is shown that the mobility and manipulation of the structural system are enhanced. Using principles of mechanics, a nonlinear dynamic model is presented to modulate the torque produced by the network of spatially distributed gyroscopes. Equations of motion, formulated as a second-order matrix differential equation, provide a trajectory for the nodal displacement of the bars, along with the wheel's spin degree of freedom. While the gyroscopic robotics concept is scalable to an arbitrarily large network, this research aims to identify elemental modules to override fundamental design principles of the innovative structural systems. Dynamic simulation and experimental verification on a planar D-bar tensegrity structure are used to demonstrate the utility of one such fundamental building block of the gyroscopic robotic system.

A New In-Flight Alignment Method with an Application to the Low-Cost SINS/GPS Integrated Navigation System.

The optimization-based alignment (OBA) methods, which are implemented by the optimal attitude estimation using vector observations—also called double-vectors—have proven to be effective at solving the in-flight alignment (IFA) problem. However, the traditional OBA methods are not applicable for the low-cost strap-down inertial navigation system (SINS) since the error of double-vectors will be accumulated over time due to the substantial drift of micro-electronic- mechanical system (MEMS) gyroscope. Moreover, the existing optimal estimation method is subject to a large computation burden, which results in a low alignment speed. To address these issues, in this article we propose a new fast IFA method based on modified double-vectors construction and the gradient descent method. To be specific, the modified construction method is implemented by reducing the integration interval and identifying the gyroscope bias during the construction procedure, which improves the accuracy of double-vectors and IFA; the gradient descent scheme is adopted to estimate the optimal attitude of alignment without complex matrix operation, which results in the improvement of alignment speed. The effect of different sizes of mini-batch on the performance of the gradient descent method is also discussed. Extensive simulations and vehicle experiments demonstrate that the proposed method has better accuracy and faster alignment speed than the related traditional methods for the low-cost SINS/global positioning system (GPS) integrated navigation system

A Design Methodology of Digital Control System for MEMS Gyroscope Based on Multi-Objective Parameter Optimization.

This paper presents a novel multi-objective parameter optimization method based on the genetic algorithm (GA) and adaptive moment estimation (Adam) algorithm for the design of a closed-loop control system for the sense mode of a Microelectromechanical systems (MEMS) gyroscope. The proposed method can improve the immunity of the control system to fabrication tolerances and external noise. The design procedure starts by deriving a parameterized model of the closed-loop of the sense mode. The loop parameters are then optimized by the GA. Finally, the ensemble of optimized loop parameters is tested by Monte Carlo analysis to obtain a robust optimal solution. Simultaneously, the Adam-least mean square (LMS) demodulator, which is appropriate for the demodulation of very noisy signals, is also presented. Compared with the traditional method, the time consumption of the design process is reduced significantly. The digital control system is implemented by the print circuit board based on embedded Field Programmable Gate Array (FPGA). The experimental results show that the optimized control loop has achieved a better performance, the system bandwidth in open-loop and optimal closed-loop control system is about 23 Hz and 101 Hz, respectively. Compared to a non-optimized closed-loop system, the bias instability reduced from 0.0015°/s to 7.52 × 10−4°/s, the scale factor increased from 17.7 mV/(°/s) to 23 mV/(°/s) and the non-linearity of the scale factor reduced from 0.008452% to 0.006156%.

Analytical approach to solving dynamic problems on resonators

A sensitive element, its geometric features, and errors affecting the performance characteristics of the product are considered in this article. The analysis was carried out, which showed that the main contribution to the self-care of the angle is made by such errors as elastic-mass defects of the quartz resonator, inaccuracy of the assembly of the structure, errors in the shooting and control system, geometric errors of the resonator. The influence of such errors as the frequency response and the quality difference on the final characteristics of the navigation device is estimated. An urgent task is to improve the control component and increase the accuracy of the entire measuring system of a solid-state wave gyroscope. The use of adaptive automatic control systems provides setting the resonant frequency of the sensitive element, capturing the natural frequency of oscillations, generating signals of the mismatch of the amplitude of oscillations, etc. To improve the efficiency of the automatic control system, to reduce the time to bring the device to the required level of quality, a mathematical model is being developed. This article discusses the model of the circuit of automatic suppression of dissimilarity for the push-pull control system of a solid-state wave gyro. An assumption has been made that it is possible to apply the results of simulation modeling for the further implementation of the circuit of suppressing different-Q-factors in the navigation block.

WiWeHAR: Multimodal Human Activity Recognition Using Wi-Fi and Wearable Sensing Modalities

Robust and accurate human activity recognition (HAR) systems are essential to many human-centric services within active assisted living and healthcare facilities. Traditional HAR systems mostly leverage a single sensing modality (e.g., either wearable, vision, or radio frequency sensing) combined with machine learning techniques to recognize human activities. Such unimodal HAR systems do not cope well with real-time changes in the environment. To overcome this limitation, new HAR systems that incorporate multiple sensing modalities are needed. Multiple diverse sensors can provide more accurate and complete information resulting in better recognition of the performed activities. This article presents WiWeHAR-a multimodal HAR system that uses combined Wi-Fi and wearable sensing modalities to simultaneously sense the performed activities. WiWeHAR makes use of standard Wi-Fi network interface cards to collect the channel state information (CSI) and a wearable inertial measurement unit (IMU) consisting of accelerometer, gyroscope, magnetometer sensors to collect the user's local body movements. We compute the time-variant mean Doppler shift (MDS) from the processed CSI data and magnitude from the inertial data for each sensor of the IMU. Thereafter, we separately extract various time- and frequency-domain features from the magnitude data and the MDS. We apply feature-level fusion to combine the extracted features, and finally supervised learning techniques are used to recognize the performed activities. We evaluate the performance of WiWeHAR by using a multimodal human activity data set, which was obtained from 9 participants. Each participant carried out four activities, such as walking, falling, sitting, and picking up an object from the floor. Our results indicate that the proposed multimodal WiWeHAR system outperforms the unimodal CSI, accelerometer, gyroscope, and magnetometer HAR systems and achieves an overall recognition accuracy of 99.6%-100%.

Coupled Dynamic Modeling and Analysis of the Single Gimbal Control Moment Gyroscope Driven by Ultrasonic Motor

A control moment gyroscope (CMG) is a key actuator for spacecraft's attitude and stability control. But there exist micro-vibrations from high-speed flywheel, which will affect the performance of the spacecraft greatly. Due to the unbalanced mass and the supporting structure, the high-speed rotating flywheel could generate disturbance torque, which will be passed to the gimbal to deteriorate the gimbal servo system. At the same time, the rotation of the gimbal will increase the disturbance torque for gyroscopic effect. According · to the bearing theory, the stiffness of the bearing is affected by the load that applied on it, which results the influence on the flywheel vibration and the generated disturbance torque. This means that there is a coupling effect in the CMG. In this article, we focused on this coupling relationship between the flywheel vibration and the gimbal rotation in a single gimbal control moment gyroscope (SGCMG) system. Firstly, a vibration model of the flywheel with variable stiffness supporting is established. And the rotation model of the gimbal is also developed. The flywheel model and the gimbal model are coupled with each other through the variable stiffness supporting and gyroscope effect. Based on the numerical simulations the interactions among the bearing stiffness, the flywheel vibration and the gimbal rotation are analyzed. Finally, experiments are carried out on the prototype. The experimental results have verified the theoretical analysis and the simulations, and which would support the design of high-performance control system.

Design and Experiment for Dual-Mass MEMS Gyroscope Sensing Closed-Loop System

A closed-loop controlling system for Micro Electro Mechanical System (MEMS) gyroscope sense mode is investigated in this paper, and the controller is designed to achieve low error, wide bandwidth and low noise capability. The gyroscope monitoring system includes four independent closed-loop, and is simulated by Simulink soft to prove the speedability and stability of the sensing closed-loop. The gyroscope monitoring system is realized through 3 analog circuit boards, and is tested through temperature controlled turntable. The bias stability, angular random walking value and bias temperature coefficients improved from 2.168 °/h, 0.155°/ $\surd \text{h}$ and 10.59 °/h/°C to 0.415 °/h, 0.0414°/ $\surd \text{h}$ and 3.59°/h/°C. And the bandwidth value is improved from 13Hz to 104Hz. Meanwhile, scale factor nonlinearity, asymmetry, repeatability and temperature coefficient parameters are enhanced from 660 ppm, 430ppm, 403ppm and 180 ppm/°C to 59.3ppm, 62.4ppm, 50.4ppm and 28.7 ppm/°C respectively.

Parameter-dependent H∞ control for MEMS gyroscopes: synthesis and analysis

The accuracy of micro-electro-mechanical systems (MEMS) gyroscopes is sensitive to variations of the drive mode resonance frequency ω0. To tackle this problem, we propose an H∞ control, which explicitly depends on ω0 and guarantees, with reduced conservatism, a specified level of performance of the drive mode. We consider the design of continuous- and discrete-time controllers. We then propose a method based on the µ-analysis to validate the performance of drive mode control even if the frequency ω0 is not perfectly measured. Numerical examples confirm the effectiveness of our approach.

Event-Triggered Output Feedback Control for MEMS Gyroscope With Prescribed Performance

This paper investigates an event-triggered output feedback control problem with guaranteed tracking performance for microelectromechanical system (MEMS) gyroscope subject to the lumped disturbances, including parameter uncertainties, coupling between driving mode and sensing mode, and unknown external disturbances. Firstly, to make the system output tracking errors evolve within the predetermined performance envelopes, a prescribed performance control (PPC) is employed in our controller design, such that a prescribed trajectory tracking with preselected settling time and steady-state tracking accuracy can be ensured. Besides, to simultaneously realize disturbance rejection and estimation of the immeasurable velocity state, linear extended state observers (LESOs) are designed to reconstruct the lumped disturbances and immeasurable velocity states for both MEMS gyroscope driving and sensing modes. In general, excessively energy and resource consumption are fundamentally neglected in most of the existing output feedback controllers for MEMS gyroscope, which will dramatically reduce the operational time of the close-loop system. To address this problem, we embed a fixed threshold event-triggered mechanism into the controller design procedure, such that the communication data size can be drastically reduced without sacrificing the tracking accuracy. Finally, to obtain the close-loop stability for MEMS gyroscope, robust control laws are designed to compensate for the measurement error and estimation error, meanwhile Zeno phenomena can be effectively eliminated. The simulation results and comparisons validate the effectiveness of the proposed scheme.

Neural Adaptive Control for MEMS Gyroscope with Full-State Constraints and Quantized Input

In this article, we investigate the neural adaptive quantized control problem for microelectromechanical system (MEMS) gyroscope with full-state constraints and lumped disturbances. With two different kinds of one-to-one nonlinear mappings, the traditional gyroscope model with matched disturbances is transformed into an unconstrained one with both unmatched and matched disturbances, thus the predefined time-varying state constraints imposed on MEMS gyroscope can be achieved. To compensate for the lumped disturbances, a state estimator-based minimal learning parameter neural network is proposed to obtain fast and smooth disturbance estimates for both position and velocity control loops, which not only can eliminate the poor transient behaviors that widely appear in the available neural adaptive control with a large adaptive gain, but also greatly reduce the number of leaning parameters updated online. Furthermore, by employing a hysteresis logarithmic quantizer, the neglected difficulty, named as constrained data bandwidth of actuator can be overcome with less chattering in control signal, which is more convenient to implement. Finally, the neural adaptive control for MEMS gyroscope is developed such that satisfactory tracking performance is achieved despite of large disturbances, full-state constraints as well as quantized input. The effectiveness and advantages of the proposed control method are demonstrated through extensive simulations.

MLP-Based Neural Guaranteed Performance Control for MEMS Gyroscope With Logarithmic Quantizer

In this paper, a minimum-learning-parameter (MLP) based neural control method is proposed for micro-electro-mechanical system (MEMS) gyroscope with prescribed performance and input quantization. For the first time, a logarithmic quantizer (LQ) is employed to generate smooth input control signal for MEMS gyroscope, which greatly reduces the communication data size as well as actuator bandwidth. To improve the performance of MEMS gyroscope in the presence of quantization error, a prescribed performance control scheme consisting of preselected performance boundaries and an error transformation is utilized, such that preselected transient and steady-state properties can be assured. In contrast to the neural control strategies subject to the issue of learning explosion, a MLP-based neural network (NN) is introduced to estimate the unknown uncertainties using the norm of neural weight. To eliminate the effect of quantization error induced by LQ, a robust quantized control is designed to further ensure the closed-loop system suffering from discontinuous dynamics with prescribed ultimately uniformly bounded (UUB) performance. In the end, a series of simulations are presented to validate the superiority of the proposed control methodology.

DESIGNING THE PRINCIPAL TRANSMISSION SCHEME FIBER OPTIC DEVICE FIBER OPTICAL GYROSCOPE

The subject of the article is the fiber-optic fiber-optic gyro system used in inertial navigation, control and stabilization systems. The purpose of the article is to study the design of the schematic diagram of the transmitting device of the optical fiber system and to make the necessary calculations for the transmitting device of the optical fiber system. Problem to be solved is the justification of technical solutions, the implementation of which in the practice of measurement will allow to substantiate the process of designing the schematic diagram of the transmission device of the fiber-optic system of the fiber-optic gyroscope used in inertial navigation, control and stabilization systems. The article deals with: stages of designing the schematic diagram of the transmitting device of the fiber optical system; certain calculations have been made regarding the damping of the site in relation to the designed single-fiber communication system; diagram of the optical transmission device under development. Conclusions: It is advisable to use the proposed technical solutions both in the modernization of existing fiber-optic gyroscopes and in the creation of perspective samples intended for use in inertial navigation, control and stabilization systems

The Application of High Efficiency and Low Noise Switching Power Supply in Fiber Optic Gyroscope

For high-precision fiber optic gyro systems, the efficiency and noise in the switching power source limits its application and also affects the system's light source and signal processing circuit, resulting in output errors. The interference mechanism of switching power supply ripple noise on super luminescent diode (SLD) light source and demodulation module in fiber optic gyro system is analyzed. A high-efficiency and low-noise switching power supply based on synchronous rectification is proposed. The power supply uses RC circuit to realize adjustable switching frequency. The push-pull isolation topology, LC filter and LDO regulator circuit are used to achieve constant voltage output with peak-to-peak ripple noise of less than 1mV. The conversion efficiency of the switching power supply is improved by 10%, which provides a high-quality power source for the high-precision fiber optic gyroscope. In the meanwhile, the switching power source for FOG is 541cm in size, which is beneficial to the miniaturization of inertial navigation system.