Browsing by Author "Chen, Tsung-Lin"

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A Constrained Wheel Torque Controller for Lane Following System Using Control Distribution
(2010)
Hsu, Ling-Yuan
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Weng, Kent
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Chen, Tsung-Lin
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機械工程學系
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Department of Mechanical Engineering
A lane following system is proposed that employs four constrained wheel torques to regulate a vehicle on a reference trajectory. The proposed control algorithm was developed by combining several techniques such as: DYC method, hierarchical control architecture, sliding mode controls, control distributions, and etc. Different from existing approaches, the proposed method has the following advantages: (1) it can be implemented on two-wheel drive vehicles; (2) the error resulting from the hierarchical architecture are minimized and compensated; (3) the controlled wheel torque calculated by the control distribution method is an analytical solution instead of from numerical search. The proposed controller is evaluated by simulations on two more complex vehicle models: a full-state vehicle model and a sedan model from commercial software Carsim. Simulation results indicate that, in both cases, the proposed method can regulate the vehicle to finish a single lane change when the vehicle is moving at an initial speed of 90 km/hr.
A Gyroscope Control System for Unknown Proof Mass and Interface Circuit Errors
(2010)
Chi, Chien-Yu
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Chen, Tsung-Lin
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機械工程學系
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Department of Mechanical Engineering
This paper presents a novel approach that can compensate errors resulting from the imperfections of mechanical structures and interface circuits for MEMS gyroscope systems. The mechanical structure errors discussed in this paper contribute to unknown proof mass, spring constants, damping coefficients, and existence of cross-axis resilient/damping forces. The interface circuit errors include: mismatch of differential capacitors, parasitic capacitance, offset voltage of operation amplifiers, and circuit noise. Different from most of existing researches, the proposed method has the following features: (1) the mechanical structure imperfections and interface circuit errors are compensated simultaneously using control techniques; (2) the mass of the proof mass can be unknown. This approach is verified on two types of gyroscope designs by numerical simulations. Simulation results indicate that, under those imperfections, the proposed method can obtain correct angular rate within 80 milliseconds.
A NEW GAS BIO-SENSOR IN THE STRUCTURE OF A MICRO-MACHINED CLAMPED-CLAMPED INERTIAL BEAM AND ITS READOUT CIRCUIT
(2012)
Xue, Bing-Ze
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Chao, Paul C-P
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Lin, Bor-Shyh
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Tsai, Chun-Yin
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Chen, Tsung-Lin
This study presents a novel gas bio-sensor in the form of a micro-machined resonator and its readout circuit. The resonator has the structure of a clamped-clamped beam with thermal actuation and piezo-resistive sensing that supports a plate capable of being attached with test gas molecules to detect gas concentration. The purpose of this study is to design and fabricate the micro-scaled inertial beam with its readout circuit in a system-on-chip package. The circuit includes a driver, a front-end converter, a feed-trough reduction unit, a square-wave converter and a phase detector. In the process of signal reading,, the sensor is first driven by a DDS module and power amplifier, and then sense the vibrations by piezo-resistivity. The piezo-resistivity is detected by a Wheatstone bridge circuits. The carried signal of modulation is processed by a Wheatstone bridge circuits. An instrumentation amplifier adjusts the gain to the appropriate amplitude. The circuit with reduction on feed-through noise increases the SNR. Square wave conversion circuit and PFD process the signal and the driver reference signal to detect phase difference. The data of phase difference is counted into a microcontroller dsPIC4011 and then the data being transmitted to the computer by RS232 to a USB adapter. Finally, the whole circuit is implemented by using TSMC 0.35 2P4M process and one-step post-processing.
A Novel Gas Sensor in the Form of Micro-machined Resonator and its Readout Circuit
(2011)
Xue, Bing-Ze
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Chao, Paul C. -P.
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Lin, Bor-Shyh
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Tsai, Chun-Yin
;
Chen, Tsung-Lin
This study presents a novel gas sensor in the form of a micro-machined resonator and its readout circuit. The resonator has the structure of clamped-clamped beams with thermal actuation and piezo-resistive sensing that supports a plate capable of being attached with test gas molecules to detect gas concentration. The purpose of this study was to design a new gas sensor readout system for a clamped-clamped beam resonator with thermal actuation and piezo-resistive sensing and also presents a new approach to reject the feed-through noise. The sensor is driven by a DDS module and power amplifier, and then sense the vibrations by piezo-resistivity. The piezo-resistivity is detected by a Wheatstone bridge circuits. The carried signal of modulation is set in Wheatstone bridge circuits. An instrumentation amplifier adjusts the gain to the appropriate amplitude. The circuit with reduction on feed-through noise increases the SNR. Square wave conversion circuit and PFD process the signal and the driver reference signal to detect phase difference. The data of phase difference is counted into a microcontroller dsPIC4011 and then the data being transmitted to the computer by RS232 to a USB adapter. Finally, the whole circuit is implemented by using TSMC 0.35 mu m 2P4M process and one-step post-processing.
An optimal design of thermal-actuated and piezoresistive-sensed CMOS-MEMS resonant sensor
(2013-11-01)
Wang, Chun-Chieh
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Tsai, Chun-Yin
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Chen, Tsung-Lin
;
Liao, Sin-Hao
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機械工程學系
This paper proposes an optimal design of the thermal-actuated, piezoresistive-sensed resonator fabricated by a foundry-provided CMOS-MEMS process. The optimal design is achieved both by quantitatively comparing the mechanical properties of different composite films as well as by deriving an analytical model for determining the device dimensions. The analytical model includes a stress model of an asymmetric mechanical structure and a piezoresistivity model of the heavily doped, n-type polysilicon film. The analytical model predicts that the optimal length of the displacement sensor is 200 mu m when the thermal actuator is 200 mu m in length and the absorption plate is 100 mu m in length. Additionally, the model predicts the resistivity of the polysilicon film of (6.8 +/- 2.2) m Omega cm and the gauge factor of (6.8 +/- 2.9) when the grain size is (250 +/- 100) nm. Experimental results agree well with simulation results. Experimental data show that the resonant frequency of the device is 80.06 kHz and shifts to 79.8 kHz when a brick of Pt mass is deposited on the resonator. The mass of the Pt estimated from the frequency shift is 4.5419 x 10(-12) kg, while estimated from the measured dimension is 4.4204 x 10(-12) kg. Sensitivity of the resonant sensor is calculated to be 1.8 x 10(2) Hz ng(-1). Experimental results further show that the polysilicon film used in the experiments has a grain size of (241 +/- 105) nm, an average gauge factor of 5.56 and average resistivity of 5.5 m Omega cm.
An Optimal Wheel Torque Distribution Controller for Automated Vehicle Trajectory Following
(2013-07-01)
Hsu, Ling-Yuan
;
Chen, Tsung-Lin
;
機械工程學系
;
Department of Mechanical Engineering
This paper proposes an automated vehicle trajectory following system that uses four constrained wheel torques to regulate a vehicle on a reference trajectory. The constrained wheel torques can be achieved using the two-wheel drive and differential brakes. The proposed control algorithm is developed using the following steps. First, the sliding-mode control is used to find stability constraints for trajectory following when the vehicle system is subjected to modeling errors. Second, these stability constraints, along with other actuator constraints, are particularly tuned for the proposed control distribution method. The proposed control distribution method determines four longitudinal tire forces and minimizes actuator control efforts. Finally, these tire forces are converted to traction/braking wheel torques. The proposed method has the following advantages: 1) It achieves both robust trajectory following and optimal control efforts, 2) the optimal control effort is obtained analytically instead of from a numerical search, and 3) the robust performance of this vehicle control system can be theoretically verified. The proposed method is evaluated using numerical simulations on two front-drive vehicle models: a full-state vehicle model and a sedan model from the Carsim commercial software. The simulation results indicate that, in both cases, the proposed method can regulate the vehicle to finish a "double-lane change" when the vehicle is moving at an initial speed of 90 km/h. The maximum lateral acceleration is 6.56 m/s(2), and the regulated position error is less than 6.9 cm.
Applying a Three-Antenna GPS and Suspension Displacement Sensors to a Road Vehicle
(2009)
Hsu, Ling-Yuan
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Chen, Tsung-Lin
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機械工程學系
;
Department of Mechanical Engineering
This paper presents a novel sensor fusion system for road vehicles, which mainly composed of a three-antenna global positioning system (GPS), and four suspension displacement sensors. This sensor system not only obtains accurate six degree-of-freedom (DOF) information for vehicle dynamics but also road angles in real time. The road angles and vehicle attitude are difficult to be detected using on-board sensors because they are often coupled in the sensor measurements. Most approaches ignore this coupling effect; only a few try to obtain them by state estimations using vehicle models. The proposed method solve this problem, without requiring any vehicle model, by incorporating a non-inertial sensor (suspension displacement sensors) with inertial sensors (three-antenna GPS). In a demonstrating case, an additional inertial measurement unit (IMU) is included in the senor system to improve the estimation accuracy. Simulation results indicate that the accuracy of the estimated vehicle attitude is less than 0.85 deg, and that of the estimated road angles is less than 0.3 deg. Additionally, the estimation accuracy of the vertical displacement is improved from 3 m to 0.248 m.
Compensation of Interface Circuit Errors for MEMS Gyroscopes Using State Observers
(2008)
Chi, Chien-Yu
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Peng, Yen-Pin
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Chen, Tsung-Lin
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機械工程學系
;
Department of Mechanical Engineering
This paper presents a novel approach that can compensate the error resulting from interface circuits for MEMS gyroscopes. Different from most of existing researches on gyroscopes wherein the interface circuits are either assumed to be ideal or optimized individually, this approach uses state estimation techniques to compensate the errors resulting from interface circuits and mechanical structure uncertainties, and to obtain correct angular rates for gyroscope systems. In a simulation case where the imperfections of interface circuits include: offset voltages of the operational amplifiers (3 mV and drifting with time), the parasitic capacitance (2 PF), and the measurement noise (white noise, 0.5 mV), the proposed method can estimate the angular rate correctly with an estimation accuracy of 8 x 10(-4)rad/sec.
Design and analysis of a fault-tolerant coplanar gyro-free inertial measurement unit
(2008-02-01)
Chen, Tsung-Lin
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機械工程學系
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Department of Mechanical Engineering
This paper presents a novel design of a fault-tolerant, coplanar, and gyro-free inertial measurement unit (IMU) that consists of 13 single-axis linear accelerometers and can perform six degree-of-freedom (DOF) measurements for an object in motion. This design uses a combination of redundant accelerometers, an innovative real-time fault-identification technique, together with state-estimation techniques to facilitate robust six DOF measurements, even when some of its accelerometers produce faulty outputs. A design example indicates that the proposed fault-tolerant design and compensation algorithm can detect and correct the biased accelerometer outputs in real time. In this simulation example, the accelerometer measurement noise is assumed to be white and set at 0.1 m/s(2). The minimum detectable dc-offset value is 0.1 m/s(2), which is the same as the standard deviation of the accelerometer measurement noise. The compensated accelerometer outputs were used to construct an "observer-based" gyro-free IMU. The angular-velocity estimation accuracy is 4 x 10(3) rad/s, and the linear-acceleration accuracy is less than 0.24 m/s(2). The IMU output accuracy is not affected by the proposed fault-compensation algorithm.
Design and Experiment of a Power Sharing Control Circuit for Parallel Fuel Cell Modules
(2020-06-01)
Wu, Chien-Chang
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Chen, Tsung-Lin
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機械工程學系
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Department of Mechanical Engineering
In this paper, a novel control circuit that can connect fuel cell (FC) modules in parallel is proposed, which is particularly useful when the employed FCs have different electrical characteristics. Conventional methods (e.g., DC/DC converters) are not applicable in such situations because they cannot regulate the power output of each source in a parallel-connected topology. Consequently, the uniformity requirement of FCs increases and becomes costly. In contrast to existing methods, the proposed method adopts a novel power-feedback method to control the power output of each FC module under both rated conditions and load changes, which in turn determines the operating point of each FC module. Therefore, the uniformity requirement can be relaxed. For proof of concept, the experiments employed two FC-like sources with different I-V characteristics. The experimental results indicated that the power assignment under the rated condition had a relative error of < 6.62%. The distribution ratio error under the load change was < 7.43%. Therefore, the proposed method can regulate the power output (operation point) of each parallel-connected FC-like power source.
Design and fabrication of a CMOS MEMS logic gate
(2011)
Tsai, Chun-Yin
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Chen, Tsung-Lin
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Liao, Hsin-Hao
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Lin, Chen-Fu
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Juang, Ying-Zong
This study aims to develop a novel CMOS-MEMS logic gate via commercially available CMOS process (TSMC, 2P4M (R)). Compared to existing CMOS MEMS designs, which uses foundry processes, the proposed design imposes several new challenges including: carrying two voltage levels on a non-warping suspended plate, metal-to-metal contact, and etc. Different combinations of oxide-metal films and post-CMOS process are investigated to achieve a non-warping suspended structure layer. And different wet etchants are investigated to remove sacrificial layers without attacking structure layers and features. In a prototype design, the selected structure layer is metal-3 and oxide film; the device is released using AD-10 and titanium etchant; the device is 250 mu m long, 100 mu m wide, and 1.5 mu m gap. The experimental results show that the suspended plate slightly curls down 0.485 mu m. This device can be actuated by 10/0 V with a moving distance 50nm. The resonant frequency is measured at 36 kHz. Due to the damage of the tungsten plugs, the logic function can only be verified by its mechanical movements instead of electrical readouts for now.
Design and fabrication of MEMS logic gates
(2008-04-01)
Tsai, Chun-Yin
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Kuo, Wei-Ting
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Lin, Chi-Bao
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Chen, Tsung-Lin
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機械工程學系
This paper presents a novel design of MEMS logic gate that can perform Boolean algebra the same as logic devices that are composed of solid-state transistors. This MEMS logic gate design inherits all the advantages from MEMS switches and thus is expected to have more applications than MEMS switches. One unique feature of this device is that it can perform either NAND gate or NOR gate functions with the same mechanical structure but with different electrical interconnects. In a prototype design, the device is 250 mu m long, 100 mu m wide and has 1 mu m gap. The experimental results show that this device can operate at 10/0 V and achieve the proposed logic functions. The resonant frequency of the device is measured roughly at 30 kHz. Due to no metal-to-metal contact in the current device, the logic functions of the design are verified through observations and video taping.
Design and Simulation of a New Dual-Axis Control Input Piezoelectric Gyroscope
(2016)
Chang, Cheng-Yang
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Chen, Tsung-Lin
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機械工程學系
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Department of Mechanical Engineering
This paper proposed a new design of the dual-axis control input, dual-axis position measurement piezoelectric gyroscope. Using piezoelectric actuation/sensing to implement this gyroscope can be much more difficult than the conventional gyroscope, which equips only single-axis control input and dual-axis position measurement. This is because multiple mode shapes may exist in the flexure deformation, which complicates the relation between flexure deformation and the proof mass position. This paper solves this multiple-mode-shape problem by designing the location and dimensions of the electrodes such that the piezoelectric force would not excite multiple mode shapes and the voltage output of the sensing electrodes responds only to specific mode shapes. The proposed design achieves a sensitivity of 8 mu v/deg/sec for the angular rate sensing and a quadrature error of 0.007%. The low quadrature error could be one of the advantages of sensing the position of the proof mass via sensing the specific deformed shape of the flexure.
Design, fabrication and calibration of a novel MEMS logic gate
(2010-09-01)
Tsai, Chun-Yin
;
Chen, Tsung-Lin
;
機械工程學系
;
Department of Mechanical Engineering
This paper presents the design, fabrication and calibration of a novel MEMS logic gate that can perform Boolean algebra as well as logic devices composed of solid-state transistors. Unlike existing designs, the proposed design can perform either NAND gate or NOR gate functions using the same mechanical structure, but different electrical interconnects. The proposed design imposes three requirements on the fabrication process: two voltage levels carried on a suspended plate, metal-to-metal contact between shuttle electrodes and fixed electrodes, and a low process temperature (<300 degrees C). To fulfill these requirements, the residual stress in the fabricated device is substantial which could impair the functionality of the device. Therefore, a novel in situ film stress calibration method is developed to assist the development of the fabrication process. In a prototype design, the fabricated device is 250 mu m long, 100 mu m wide and of 3.97 mu m gap. Experimental results show that the device can operate at 25/-25 V and 100 Hz, and achieve the proposed logic functions. In addition, several properties of this device are experimentally evaluated, including power consumption, on/off resistance, lifetime and resonant frequency.
Design, Fabrication, and Modeling of a Novel Dual-Axis Control Input PZT Gyroscope
(2017-11-01)
Chang, Cheng-Yang
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Chen, Tsung-Lin
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機械工程學系
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Department of Mechanical Engineering
Conventional gyroscopes are equipped with a single-axis control input, limiting their performance. Although researchers have proposed control algorithms with dual-axis control inputs to improve gyroscope performance, most have verified the control algorithms through numerical simulations because they lacked practical devices with dual-axis control inputs. The aim of this study was to design a piezoelectric gyroscope equipped with a dual-axis control input so that researchers may experimentally verify those control algorithms in future. Designing a piezoelectric gyroscope with a dual-axis control input is more difficult than designing a conventional gyroscope because the control input must be effective over a broad frequency range to compensate for imperfections, and the multiple mode shapes in flexural deformations complicate the relation between flexural deformation and the proof mass position. This study solved these problems by using a lead zirconate titanate (PZT) material, introducing additional electrodes for shielding, developing an optimal electrode pattern, and performing calibrations of undesired couplings. The results indicated that the fabricated device could be operated at 5.5 +/- 1 kHz to perform dual-axis actuations and position measurements. The calibration of the fabricated device was completed by system identifications of a new dynamic model including gyroscopic motions, electromechanical coupling, mechanical coupling, electrostatic coupling, and capacitive output impedance. Finally, without the assistance of control algorithms, the open loop sensitivity of the fabricated gyroscope was 1.82 V/deg/s with a nonlinearity of 9.5% full-scale output. This sensitivity is comparable with those of other PZT gyroscopes with single-axis control inputs.
Dynamic Modeling of a Parallel-Connected Solid Oxide Fuel Cell Stack System
(2020-01-01)
Wu, Chien-Chang
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Chen, Tsung-Lin
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機械工程學系
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Department of Mechanical Engineering
This study proposes novel simulation methods to model the power delivery function of a parallel-connected solid-oxide-fuel-cell stack system. The proposed methods are then used to investigate the possible thermal runaway induced by the performance mismatch between the employed stacks. A challenge in this modeling study is to achieve the same output voltage but different output current for each employed stack. Conventional fuel-cell models cannot be used, because they employ fuel flow rates and stack currents as the input variables. These two variables are unknown in the parallel-connected stack systems. The proposed method solves the aforementioned problems by integrating the fuel supply dynamics with the conventional stack models and then arranging them in a multiple-feedback-loop configuration for conducting simulations. The simulation results indicate that the proposed methods can model the transient response of the parallel-connected stack system. Moreover, for the dynamics of the power distribution, there exists an unstable positive feedback loop between employed stacks when the stack temperatures are low, and a stable negative feedback loop when the stack temperatures are high. A thermal runaway could be initiated when the dynamics of the stack temperature is slower than that of the current distribution.
Estimating Road Angles With the Knowledge of the Vehicle Yaw Angle
(2010-05-01)
Hsu, Ling-Yuan
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Chen, Tsung-Lin
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機械工程學系
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Department of Mechanical Engineering
This paper presents a method of estimating road angles using state observers and three types of sensors (lateral acceleration sensors, longitudinal velocity sensors, and suspension displacement sensors). The proposed method differs from those in most existing literature in three aspects. First, a "full-state" vehicle model is used to describe nonlinear vehicle dynamics on a sloped road. Second, "switching observer" techniques are used to suggest suitable sensors and to construct state observers. Lastly, the road angles are described by three Euler angles, and two of them are estimated simultaneously. The analysis indicates that (1) road angles affect vehicle dynamics through components of the gravitational force acting on the vehicle body. These gravitational forces can be correctly estimated with an estimation accuracy less than 7.5%, even when road angles vary with time. (2) Those road angles can be correctly estimated only when the vehicle yaw angle is known.
Learning-based risk assessment and motion estimation by vision for unmanned aerial vehicle landing in an unvisited area
(2019-11-01)
Cheng, Hsiu-Wen
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Chen, Tsung-Lin
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Tien, Chung-Hao
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機械工程學系
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光電工程學系
We proposed a vision-based methodology as an aid for an unmanned aerial vehicle (UAV) landing on a previously unsurveyed area. When the UAV was commanded to perform a landing mission in an unknown airfield, the learning procedure was activated to extract the surface features for learning the obstacle appearance. After the learning process, while hovering the UAV above the potential landing spot, the vision system would be able to predict the roughness value for confidence in a safe landing. Finally, using hybrid optical flow technology for motion estimation, we successfully carried out the UAV landing without a predefined target. Our work combines a well-equipped flight control system with the proposed vision system to yield more practical versatility for UAV applications. (C) The Authors. Published by SPIE under a Creative Commons Attribution 4.0 Unported License.
MEMS Gyroscope Control Systems for Direct Angle Measurements
(2009)
Chi, Chien-Yu
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Chen, Tsung-Lin
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交大名義發表
;
National Chiao Tung University
This paper presents a control algorithm for vibrating gyroscopes so that they can directly measure the rotation angle without integrating the angular rate. In most gyroscope systems, the rotation angles were obtained by integrating the angular rate, thus suffer from the error accumulation problem. Only a few papers reported that they could compensate the imperfect dynamics in gyroscopes and obtain the rotation angle directly. However, they either required a calibration phase prior to the normal operation or their stability was not theoretically proven. This paper proposes a one-step control algorithm so that imperfection compensation and angle measurement can be done simultaneously. In a demonstrating case, the mechanical structure uncertainties caused 10%similar to 20% parameter variations in a gyroscope system; the signal are contaminated by zero-mean white noise with the PSD of 2.3 x 10(-15) (ms(-1)) / H z; the angular rate to be measured is 4sin(2 pi x 40t) rad/sec. The proposed algorithm can obtain the rotation angle with an accuracy less than 0.5 degree.
Motion Estimation by Hybrid Optical Flow Technology for UAV Landing in an Unvisited Area
(2019-03-20)
Cheng, Hsiu-Wen
;
Chen, Tsung-Lin
;
Tien, Chung-Hao
;
機械工程學系
;
光電工程學系
The capability of landing on previously unvisited areas is a fundamental challenge for an unmanned aerial vehicle (UAV). In this paper, we developed a vision-based motion estimation as an aid to improve landing performance. As an alternative to the common scenarios accompanying by external infrastructures or well-defined marker, the proposed hybrid framework can successfully land on a new area without any prior information about guiding marks. The implementation was based on the optical flow technique associated with a multi-scale strategy to overcome the decreasing field-of-view during the UAV descending. Compared with a commercial Global Positioning System (GPS) through a sequence of flight trials, the vision-aided scheme can effectively minimize the possible sensing error, thus, leading to a more accurate result. Moreover, this work has potential to integrate the fast-growing image learning process and yields more practical versatility for UAV applications in the future.