The Experts below are selected from a list of 337551 Experts worldwide ranked by ideXlab platform
Ge Ren - One of the best experts on this subject based on the ideXlab platform.
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enhanced disturbance observer based on acceleration measurement for fast steering mirror systems
IEEE Photonics Conference, 2017Co-Authors: Chao Deng, Tao Tang, Yao Mao, Ge RenAbstract:In this paper, a modified disturbance observer (DOB) for fast steering mirror (FSM) optical system based on a charge-coupled device (CCD) and inertial sensors is proposed. Combining DOB with the classical cascaded multi-loop feedback control (MFC), including position loop, velocity loop, acceleration loop, the disturbance suppression performance of line-of-sight (LOS) in FSM system can be significant improved. However, due to the quadratic differential in the FSM acceleration Open-Loop Response, in fact, it is very difficult to realize an integral algorithm to compensate a quadratic differential in practical application. Thus, the conventional DOB controller has to be simplified further to make a concession, which eventuates in still insufficient disturbance compensation, particularly at low frequency. To solve this problem, an enhanced disturbance observer (EDOB) control structure, which changes the compensation plant to be the acceleration Open-Loop and avoids the saturation of double integration skillfully, is proposed. The recommended method optimizes the controller design, which is conducive to controller fulfillment in practical systems. A series of comparative experimental results demonstrate the disturbance suppression performance of the FSM control system can be effectively improved by the proposed approach.
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enhanced disturbance observer based on acceleration measurement for fast steering mirror systems
IEEE Photonics Journal, 2017Co-Authors: Chao Deng, Tao Tang, Yao Mao, Ge RenAbstract:In this paper, a modified disturbance observer (DOB) for fast steering mirror (FSM) optical system based on a charge-coupled device (CCD) and inertial sensors is proposed. Combining a DOB with the classical cascaded multiloop feedback control, including position loop, velocity loop, and acceleration loop, that the disturbance suppression performance of line-of-sight in an FSM system can be significant improved. However, due to the quadratic differential in the FSM acceleration Open-Loop Response, in fact, it is very difficult to realize an integral algorithm to compensate a quadratic differential in practical application. Thus, the conventional DOB controller has to be simplified further to make a concession, which eventuates in still insufficient disturbance compensation, particularly at low frequency. To solve this problem, an enhanced DOB control structure, which changes the compensation plant to be the acceleration Open-Loop and avoids the saturation of double integration skillfully, is proposed. The recommended method optimizes the controller design, which is conducive to controller fulfillment in practical systems. A series of comparative experimental results demonstrate that the disturbance suppression performance of the FSM control system can be effectively improved by the proposed approach.
Peter Hogg - One of the best experts on this subject based on the ideXlab platform.
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Closed-loop control of compression paddle motion to reduce blurring in mammograms
Medical Physics, 2017Co-Authors: Wang Kei, David Howard, Peter HoggAbstract:Background: Since the introduction of full field digital mammography (FFDM) a large number of UK breast cancer screening centers have reported blurred images, which can be caused by movement at the compression paddle during image acquisition. Purpose: To propose and investigate the use of position feedback from the breast side of the compression paddle to reduce the settling time of breast side motion. Method: Movement at the breast side of the paddle was measured using two calibrated linear potentiometers. A mathematical model for the compression paddle, machine drive and breast was developed using the paddle movement data. Simulation software was used to optimize the position feedback controller parameters for different machine drive time constants and simulate the potential performance of the proposed system. Results: The results obtained are based on simulation alone and indicate that closed-loop control of breast side paddle position dramatically reduced the settling time from over 90 seconds to less than 4 seconds. The effect of different machine drive time constants on the Open-Loop Response is insignificant. With closed-loop control, the larger the time constant the longer the time required for the breast side motion to settle. Conclusions: Paddle motion induced blur could be significantly reduced by implementing the proposed closed-loop control.
Chao Deng - One of the best experts on this subject based on the ideXlab platform.
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enhanced disturbance observer based on acceleration measurement for fast steering mirror systems
IEEE Photonics Conference, 2017Co-Authors: Chao Deng, Tao Tang, Yao Mao, Ge RenAbstract:In this paper, a modified disturbance observer (DOB) for fast steering mirror (FSM) optical system based on a charge-coupled device (CCD) and inertial sensors is proposed. Combining DOB with the classical cascaded multi-loop feedback control (MFC), including position loop, velocity loop, acceleration loop, the disturbance suppression performance of line-of-sight (LOS) in FSM system can be significant improved. However, due to the quadratic differential in the FSM acceleration Open-Loop Response, in fact, it is very difficult to realize an integral algorithm to compensate a quadratic differential in practical application. Thus, the conventional DOB controller has to be simplified further to make a concession, which eventuates in still insufficient disturbance compensation, particularly at low frequency. To solve this problem, an enhanced disturbance observer (EDOB) control structure, which changes the compensation plant to be the acceleration Open-Loop and avoids the saturation of double integration skillfully, is proposed. The recommended method optimizes the controller design, which is conducive to controller fulfillment in practical systems. A series of comparative experimental results demonstrate the disturbance suppression performance of the FSM control system can be effectively improved by the proposed approach.
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enhanced disturbance observer based on acceleration measurement for fast steering mirror systems
IEEE Photonics Journal, 2017Co-Authors: Chao Deng, Tao Tang, Yao Mao, Ge RenAbstract:In this paper, a modified disturbance observer (DOB) for fast steering mirror (FSM) optical system based on a charge-coupled device (CCD) and inertial sensors is proposed. Combining a DOB with the classical cascaded multiloop feedback control, including position loop, velocity loop, and acceleration loop, that the disturbance suppression performance of line-of-sight in an FSM system can be significant improved. However, due to the quadratic differential in the FSM acceleration Open-Loop Response, in fact, it is very difficult to realize an integral algorithm to compensate a quadratic differential in practical application. Thus, the conventional DOB controller has to be simplified further to make a concession, which eventuates in still insufficient disturbance compensation, particularly at low frequency. To solve this problem, an enhanced DOB control structure, which changes the compensation plant to be the acceleration Open-Loop and avoids the saturation of double integration skillfully, is proposed. The recommended method optimizes the controller design, which is conducive to controller fulfillment in practical systems. A series of comparative experimental results demonstrate that the disturbance suppression performance of the FSM control system can be effectively improved by the proposed approach.
Jonathan Simon - One of the best experts on this subject based on the ideXlab platform.
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active cancellation of acoustical resonances with an fpga fir filter
Review of Scientific Instruments, 2017Co-Authors: Albert Ryou, Jonathan SimonAbstract:We present a novel approach to enhancing the bandwidth of a feedback-controlled mechanical system by digitally canceling acoustical resonances (poles) and anti-resonances (zeros) in the Open-Loop Response via an FPGA FIR filter. By performing a real-time convolution of the feedback error signal with an inverse filter, we can suppress arbitrarily many poles and zeros below 100 kHz, each with a linewidth down to 10 Hz. We demonstrate the efficacy of this technique by canceling the ten largest mechanical resonances and anti-resonances of a high-finesse optical resonator, thereby enhancing the unity gain frequency by more than an order of magnitude. This approach is applicable to a broad array of stabilization problems including optical resonators, external cavity diode lasers, and scanning tunneling microscopes and points the way to applying modern optimal control techniques to intricate linear acoustical systems.
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active cancellation of acoustical resonances with an fpga fir filter
arXiv: Atomic Physics, 2016Co-Authors: Albert Ryou, Jonathan SimonAbstract:We present a novel approach to enhancing the bandwidth of a feedback-controlled mechanical system by digitally canceling acoustical resonances (poles) and anti-resonances (zeros) in the Open-Loop Response via an FPGA FIR filter. By performing a real-time convolution of the feedback error signal with an inverse filter, we can suppress arbitrarily many poles and zeros below 100 kHz, each with a linewidth down to 10 Hz. We demonstrate the efficacy of this technique by canceling the ten largest mechanical resonances and anti-resonances of a high-finesse optical resonator, thereby enhancing the unity gain frequency by more than an order of magnitude. This approach is applicable to a broad array of stabilization problems including optical resonators, external cavity diode lasers, and scanning tunneling microscopes, and points the way to applying modern optimal control techniques to intricate linear acoustical systems.es to intricate linear acoustical systems.
Wang Kei - One of the best experts on this subject based on the ideXlab platform.
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Closed-loop control of compression paddle motion to reduce blurring in mammograms
Medical Physics, 2017Co-Authors: Wang Kei, David Howard, Peter HoggAbstract:Background: Since the introduction of full field digital mammography (FFDM) a large number of UK breast cancer screening centers have reported blurred images, which can be caused by movement at the compression paddle during image acquisition. Purpose: To propose and investigate the use of position feedback from the breast side of the compression paddle to reduce the settling time of breast side motion. Method: Movement at the breast side of the paddle was measured using two calibrated linear potentiometers. A mathematical model for the compression paddle, machine drive and breast was developed using the paddle movement data. Simulation software was used to optimize the position feedback controller parameters for different machine drive time constants and simulate the potential performance of the proposed system. Results: The results obtained are based on simulation alone and indicate that closed-loop control of breast side paddle position dramatically reduced the settling time from over 90 seconds to less than 4 seconds. The effect of different machine drive time constants on the Open-Loop Response is insignificant. With closed-loop control, the larger the time constant the longer the time required for the breast side motion to settle. Conclusions: Paddle motion induced blur could be significantly reduced by implementing the proposed closed-loop control.
