The Experts below are selected from a list of 195 Experts worldwide ranked by ideXlab platform
Seul Jung - One of the best experts on this subject based on the ideXlab platform.
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Experimental Verification of Singularity-Robust Torque Control for a 1.2-Nm–5-Hz SGCMG
IEEE Transactions on Industrial Electronics, 2018Co-Authors: Seul JungAbstract:A single gimbal control moment gyro (SGCMG) has been designed and developed as a Torque amplifier to generate 1.2-Nm-5-Hz Gyroscopic Torque for the angle deviation of 45°. Since the SGCMG is aimed to generate the Torque accurately in the designated direction, the return of the gimbal from the disturbance should be guaranteed within a desired frequency. However, unexpected axial drift exists and leads to a null motion under the Torque control scheme. Therefore, this paper identifies the cause of axial drift and proposes a new Torque control technique with two phases of compensation. Compensator I is designed to eliminate the nonlinear axial drift modeled as a sigmoidal function through an empirical identification process. Compensator II reduces other uncertainties by integrating high-pass filtering, recursive least square, all pass filtering, and moving average filtering (MAF) process. Finally, the proposed control scheme has been verified through experimental studies.
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RLS model identification-based robust control for gimbal axis of control moment gyroscope
2017 IEEE International Conference on Advanced Intelligent Mechatronics (AIM), 2017Co-Authors: Seul JungAbstract:Control moment gyroscope(CMG) is an indirect actuator used for the attitude control tasks where actuators cannot be directly applied. Control of the gimbal position becomes important to maximize the induced Torque. As a Torque amplifier, the gimbal axis of CMG should be controlled to produce fine and regulated Torque. Since the Torque performance is dependent upon the return performance of the gimbal axis, both the magnitude and direction of Gyroscopic Torque should be controlled to achieve agility and regulation. In this paper, a robust current controller is designed with an angle restriction property by the current compensation designed through the model identification by real-time recursive least square(RLS) algorithm. Firstly, the configuration and mechanism of designed CMG is presented and the angle restriction problem is stated. Secondly, RLS algorithm is designed for online identification, implemented, and validated. Thirdly, the proposed current control scheme of gimbal axis is verified by experiments.
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AIM - RLS model identification-based robust control for gimbal axis of control moment gyroscope
2017 IEEE International Conference on Advanced Intelligent Mechatronics (AIM), 2017Co-Authors: Seul JungAbstract:Control moment gyroscope(CMG) is an indirect actuator used for the attitude control tasks where actuators cannot be directly applied. Control of the gimbal position becomes important to maximize the induced Torque. As a Torque amplifier, the gimbal axis of CMG should be controlled to produce fine and regulated Torque. Since the Torque performance is dependent upon the return performance of the gimbal axis, both the magnitude and direction of Gyroscopic Torque should be controlled to achieve agility and regulation. In this paper, a robust current controller is designed with an angle restriction property by the current compensation designed through the model identification by real-time recursive least square(RLS) algorithm. Firstly, the configuration and mechanism of designed CMG is presented and the angle restriction problem is stated. Secondly, RLS algorithm is designed for online identification, implemented, and validated. Thirdly, the proposed current control scheme of gimbal axis is verified by experiments.
Dava J. Newman - One of the best experts on this subject based on the ideXlab platform.
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Wearable CMG design for the Variable Vector Countermeasure Suit
2015 IEEE Aerospace Conference, 2015Co-Authors: Rebecca A. Vasquez, Kevin R. Duda, Akil J. Middleton, Mitchell L. Hansberry, Dava J. NewmanAbstract:The Variable Vector Countermeasure Suit (V2Suit) is a countermeasure suit for sensorimotor adaptation and musculoskeletal deconditioning in microgravity. The V2Suit consists of wearable modules containing arrays of control moment gyroscopes (CMGs) that provide a viscous resistance to motions made against a specified direction. To reduce the movement coordination and sensorimotor problems seen during and following gravity level transitions, this resistance will be felt in the direction of "down" to mimic gravity. Control moment gyroscopes are commonly used for spacecraft stabilization. The V2Suit uses a miniaturized CMG array in a body-worn system to apply Torque to the wearer's musculoskeletal joints. Miniaturizing a CMG array while still generating enough Gyroscopic Torque for suitable resistance is a main challenge in the design of the V2Suit system. The initial specification for the Torque magnitude output was set to 0.1 Nm. Various candidate CMG arrays were analyzed to determine the appropriate architecture for the array inside a V2Suit module, as well as flywheel parameters for the chosen array. The selected array is a 4 CMG pyramid array, chosen for a combination of Torque output performance and size and hardware considerations. A mechanical design for the V2Suit 4 CMG pyramid array was developed using a combination of off the shelf and custom manufactured components. Minimizing the size of the array drove many design decisions; the final module design has a 6.5 inch square footprint and is 3.5 inches tall. A brass board prototype has been fabricated based on this design.
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The V2Suit “down” tracking algorithm
2014 IEEE Aerospace Conference, 2014Co-Authors: Rebecca A. Vasquez, Kevin R. Duda, Akil J. Middleton, Dava J. NewmanAbstract:The Variable Vector Countermeasure Suit (V2Suit) is a wearable intravehicular system that will provide a viscous resistance to movements that are parallel to a specified direction of `down.' The V2Suit utilizes control moment gyroscopes (CMGs) in modules on the user's limbs that are commanded to point the Gyroscopic Torque vector perpendicular to `down' during movements. An algorithm has been developed to initialize the direction of `down' and track the V2Suit module with respect to that direction using the output of an on-board inertial measurement unit (IMU). The `down' tracking algorithm uses the angular velocity and linear acceleration outputs of the IMU to initialize and determine the direction of `down' in the local module coordinate frame. This paper describes the algorithm for initializing the direction of `down' for each of the V2Suit wearable modules, and the tracking of the module orientation and velocity with respect to that direction. IMU data from representative arm movements was collected and run through the initialization and `down' tracking algorithms to quantify performance as a function of time. The performance of the IMU and algorithm combination is used to determine the operational duration before the system must be re-initialized. This work was funded by a Phase II award from NASA's Innovative Advanced Concepts (NIAC) Program.
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Variable Vector Countermeasure Suit (V2Suit) for Space Exploration
2013 IEEE Aerospace Conference, 2013Co-Authors: Kevin R. Duda, Dava J. NewmanAbstract:The “Variable Vector Countermeasure Suit (V2Suit) for Space Exploration” is an integrated countermeasure platform to mitigate the spaceflight-induced physiologic adaptation and de-conditioning that manifests during long-duration spaceflight and gravitational transitions. The V2Suit integrates flywheel gyroscopes and inertial measurement units within a wearable module that can be placed on the body segments, and when commanded in a coordinated manner provides a “viscous resistance” during movements. The system architecture, human-system integration, and three six degree-of-freedom simulations are presented which describe the magnitude and direction of the Gyroscopic Torque and resulting force within the module during representative arm movements. The results demonstrate of the ability of the V2Suit module design to generate a reaction force along a specified direction and reject perturbations due to body kinematics - collectively illustrating the feasibility of the concept.
B. C. Han - One of the best experts on this subject based on the ideXlab platform.
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Composite Hierarchical Antidisturbance Control for Magnetic Bearing System Subject to Multiple External Disturbances
IEEE Transactions on Industrial Electronics, 2014Co-Authors: Shiqiang Zheng, B. C. Han, Lei GuoAbstract:This paper explores a composite hierarchical antidisturbance control (CHADC) scheme for the resonance vibration suppression of a high-speed rotor system supported by active magnetic bearings (AMBs) in the magnetically suspended double-gimbal control moment gyroscope (MSDGCMG). The rotor dynamics with a fictitious integral term is introduced to meet the steady-state performance requirements. Resonance disturbances caused by harmonic drive transmission and Gyroscopic Torque disturbances caused by gimbal motions are also analyzed. The augmented composite AMB system with two types of disturbances and nonlinear electromagnetic dynamics is developed. Then, a disturbance observer is constructed and a stability analysis of the closed-loop system is performed using a Lyapunov approach. Simulation results show that the exogenous disturbance can be estimated and compensated with the appropriate control parameters. Rotor run-up experiments demonstrate that the proposed method has a good performance for disturbance rejection of harmonic drive resonance vibrations under the excitation of coupling Torques. The Gyroscopic Torque disturbances with the bounded norm can also be attenuated effectively.
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Compensation control method and experimental study of magnetic bearing to improve dynamic response ability of double gimbal magnetically suspended control moment gyroscope
Jixie Gongcheng Xuebao/Journal of Mechanical Engineering, 2010Co-Authors: Shiqiang Zheng, Jiancheng Fang, B. C. HanAbstract:To solve the high-speed rotor suspension precision problem caused by quick maneuvering of double gimbal magnetically suspended control moment gyro, the nonlinear coupling characteristics among inner gimbal, outer gimbal and magnetically suspended high-speed rotor are investigated. The dynamic model of the high-speed rotor with the rotation of inner and outer gimbals is set up. The rotational inertia Torque and Gyroscopic Torque are involved in this model. Because of the uncertain disturbances and noise existing in the measurement of gimbal angular acceleration which is used as the variable of the rotational inertia Torque, angular acceleration estimations of inner and outer gimbals are carried out by using robust H∞ filtering method. According to the Torque compensation control strategy, the drive coil of magnetic bearing control system is used to produce corresponding electromagnetic force for compensation control of rotational inertia Torque and Gyroscopic Torque. Experimental results show that the H∞ has good robustness to the noise uncertainty, and the runout of magnetically suspended high-speed rotor is reduced to within 30% of that before compensation, thus improving the stability of magnetic suspension system, the suspension precision and the Torque output characteristic of control moment gyroscope. © 2010 Journal of Mechanical Engineering.
Shiqiang Zheng - One of the best experts on this subject based on the ideXlab platform.
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Composite Hierarchical Antidisturbance Control for Magnetic Bearing System Subject to Multiple External Disturbances
IEEE Transactions on Industrial Electronics, 2014Co-Authors: Shiqiang Zheng, B. C. Han, Lei GuoAbstract:This paper explores a composite hierarchical antidisturbance control (CHADC) scheme for the resonance vibration suppression of a high-speed rotor system supported by active magnetic bearings (AMBs) in the magnetically suspended double-gimbal control moment gyroscope (MSDGCMG). The rotor dynamics with a fictitious integral term is introduced to meet the steady-state performance requirements. Resonance disturbances caused by harmonic drive transmission and Gyroscopic Torque disturbances caused by gimbal motions are also analyzed. The augmented composite AMB system with two types of disturbances and nonlinear electromagnetic dynamics is developed. Then, a disturbance observer is constructed and a stability analysis of the closed-loop system is performed using a Lyapunov approach. Simulation results show that the exogenous disturbance can be estimated and compensated with the appropriate control parameters. Rotor run-up experiments demonstrate that the proposed method has a good performance for disturbance rejection of harmonic drive resonance vibrations under the excitation of coupling Torques. The Gyroscopic Torque disturbances with the bounded norm can also be attenuated effectively.
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Compensation control method and experimental study of magnetic bearing to improve dynamic response ability of double gimbal magnetically suspended control moment gyroscope
Jixie Gongcheng Xuebao/Journal of Mechanical Engineering, 2010Co-Authors: Shiqiang Zheng, Jiancheng Fang, B. C. HanAbstract:To solve the high-speed rotor suspension precision problem caused by quick maneuvering of double gimbal magnetically suspended control moment gyro, the nonlinear coupling characteristics among inner gimbal, outer gimbal and magnetically suspended high-speed rotor are investigated. The dynamic model of the high-speed rotor with the rotation of inner and outer gimbals is set up. The rotational inertia Torque and Gyroscopic Torque are involved in this model. Because of the uncertain disturbances and noise existing in the measurement of gimbal angular acceleration which is used as the variable of the rotational inertia Torque, angular acceleration estimations of inner and outer gimbals are carried out by using robust H∞ filtering method. According to the Torque compensation control strategy, the drive coil of magnetic bearing control system is used to produce corresponding electromagnetic force for compensation control of rotational inertia Torque and Gyroscopic Torque. Experimental results show that the H∞ has good robustness to the noise uncertainty, and the runout of magnetically suspended high-speed rotor is reduced to within 30% of that before compensation, thus improving the stability of magnetic suspension system, the suspension precision and the Torque output characteristic of control moment gyroscope. © 2010 Journal of Mechanical Engineering.
Kevin R. Duda - One of the best experts on this subject based on the ideXlab platform.
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Wearable CMG design for the Variable Vector Countermeasure Suit
2015 IEEE Aerospace Conference, 2015Co-Authors: Rebecca A. Vasquez, Kevin R. Duda, Akil J. Middleton, Mitchell L. Hansberry, Dava J. NewmanAbstract:The Variable Vector Countermeasure Suit (V2Suit) is a countermeasure suit for sensorimotor adaptation and musculoskeletal deconditioning in microgravity. The V2Suit consists of wearable modules containing arrays of control moment gyroscopes (CMGs) that provide a viscous resistance to motions made against a specified direction. To reduce the movement coordination and sensorimotor problems seen during and following gravity level transitions, this resistance will be felt in the direction of "down" to mimic gravity. Control moment gyroscopes are commonly used for spacecraft stabilization. The V2Suit uses a miniaturized CMG array in a body-worn system to apply Torque to the wearer's musculoskeletal joints. Miniaturizing a CMG array while still generating enough Gyroscopic Torque for suitable resistance is a main challenge in the design of the V2Suit system. The initial specification for the Torque magnitude output was set to 0.1 Nm. Various candidate CMG arrays were analyzed to determine the appropriate architecture for the array inside a V2Suit module, as well as flywheel parameters for the chosen array. The selected array is a 4 CMG pyramid array, chosen for a combination of Torque output performance and size and hardware considerations. A mechanical design for the V2Suit 4 CMG pyramid array was developed using a combination of off the shelf and custom manufactured components. Minimizing the size of the array drove many design decisions; the final module design has a 6.5 inch square footprint and is 3.5 inches tall. A brass board prototype has been fabricated based on this design.
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The V2Suit “down” tracking algorithm
2014 IEEE Aerospace Conference, 2014Co-Authors: Rebecca A. Vasquez, Kevin R. Duda, Akil J. Middleton, Dava J. NewmanAbstract:The Variable Vector Countermeasure Suit (V2Suit) is a wearable intravehicular system that will provide a viscous resistance to movements that are parallel to a specified direction of `down.' The V2Suit utilizes control moment gyroscopes (CMGs) in modules on the user's limbs that are commanded to point the Gyroscopic Torque vector perpendicular to `down' during movements. An algorithm has been developed to initialize the direction of `down' and track the V2Suit module with respect to that direction using the output of an on-board inertial measurement unit (IMU). The `down' tracking algorithm uses the angular velocity and linear acceleration outputs of the IMU to initialize and determine the direction of `down' in the local module coordinate frame. This paper describes the algorithm for initializing the direction of `down' for each of the V2Suit wearable modules, and the tracking of the module orientation and velocity with respect to that direction. IMU data from representative arm movements was collected and run through the initialization and `down' tracking algorithms to quantify performance as a function of time. The performance of the IMU and algorithm combination is used to determine the operational duration before the system must be re-initialized. This work was funded by a Phase II award from NASA's Innovative Advanced Concepts (NIAC) Program.
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Variable Vector Countermeasure Suit (V2Suit) for Space Exploration
2013 IEEE Aerospace Conference, 2013Co-Authors: Kevin R. Duda, Dava J. NewmanAbstract:The “Variable Vector Countermeasure Suit (V2Suit) for Space Exploration” is an integrated countermeasure platform to mitigate the spaceflight-induced physiologic adaptation and de-conditioning that manifests during long-duration spaceflight and gravitational transitions. The V2Suit integrates flywheel gyroscopes and inertial measurement units within a wearable module that can be placed on the body segments, and when commanded in a coordinated manner provides a “viscous resistance” during movements. The system architecture, human-system integration, and three six degree-of-freedom simulations are presented which describe the magnitude and direction of the Gyroscopic Torque and resulting force within the module during representative arm movements. The results demonstrate of the ability of the V2Suit module design to generate a reaction force along a specified direction and reject perturbations due to body kinematics - collectively illustrating the feasibility of the concept.