Combined line-of-sight error and angular position to generate feedforward control for a charge-coupled device–based tracking loop

Tang, Tao; Cai, Huaxiang; Huang, Yongmei; Ren, Guanghui

doi:10.1117/1.oe.54.10.105107

Cited by 18 publications

(9 citation statements)

References 11 publications

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“…can be easily concluded in the frequency of most concern. In other words, we can obtain the past trajectory of the target through SP, unlike traditional feedforward control, which requires additional sensors to help synthesize the trajectory [15]. Based on it, we can predict the current trajectory to eliminate the effect of the delay with a trajectory prediction method.…”

Section: ⅲ the DCCC Methodsmentioning

confidence: 99%

“…A feedforward control which can improve the control type equivalently is used to enhance the performance of delayed systems [13], [14]. Since the target information in PTS is not measurable, the current target state used for feedforward is obtained by a trajectory prediction method based on a synthesized trajectory in the past time [15], [16]. However, this kind of feedforward method requires additional sensors and its control performance decreases significantly as the frequency increases.…”

Section: Introductionmentioning

confidence: 99%

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Delay-Compound-Compensation Control for Photoelectric Tracking System Based on Improved Smith Predictor Scheme

Luo

Xue

et al. 2022

IEEE Photonics J.

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High control bandwidth is usually restricted in a photoelectric tracking system (PTS) based on a Charge-Couple Device(CCD) with time delay, which hinders a good tracking performance. Generally, a model-based delay-compensation controller called Smith predictor (SP) can help increase the controller gain to promote the bandwidth by separating delay from the control loop. However, the performance promotion is insufficient because the delay still stays in the forward channel which causes errors between output and input. And the increase of the controller gain is still limited due to the effect of model mismatch on stability. In this paper, to solve the problems, a delay-compound-compensation control (DCCC) based on improved SP by trajectory prediction and velocity feedforward is proposed. The additional trajectory prediction is used to further eliminate the effect of delay existing in the forward channel. The additional velocity feedforward is used to further reform the transfer characteristics limited by the controller gain. A Kalman filter-based design method of trajectory prediction is presented and the optimal design principle of feedback and feedforward controllers is given in the face of model mismatch. Experiments demonstrate that the DCCC is valid and could greatly promote the tracking performance in the low frequency.

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Section: ⅲ the DCCC Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Delay-Compound-Compensation Control for Photoelectric Tracking System Based on Improved Smith Predictor Scheme

Luo

Xue

et al. 2022

IEEE Photonics J.

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show abstract

“…Unfortunately, it was difficult to get the trajectory of the target and extract the disturbance signals. A predictive tracking method combining the boresight error with angular sensor for synthesizing the target trajectory was proposed to compensate the errors caused by time delay [17,18]. However, an additional position sensor was required, which was only suitable for the condition with low measurement noise.…”

Section: Introductionmentioning

confidence: 99%

Feedforward Control Based on Error and Disturbance Observation for the CCD and Fiber-Optic Gyroscope-Based Mobile Optoelectronic Tracking System

et al. 2018

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In the mobile optoelectronic tracking system (MOTS) based on charge-coupled device (CCD) and fiber-optic gyroscope (FOG), the tracking performance (TP) and anti-disturbance ability (ADA) characterized by boresight error are of equal importance. Generally, the position tracking loop, limited by the image integration time of CCD, would be subject to a non-negligible delay and low-sampling rate, which could not minimize the boresight error. Although the FOG-based velocity loop could enhance the ADA of the system, it is still insufficient in the case of some uncertain disturbances. In this paper, a feedforward control method based on the results of error and disturbance observation was proposed. The error observer (EOB) based on the CCD data and model output essentially combined the low-frequency tracking feedforward and closed-loop disturbance observer (DOB), which could simultaneously enhance the low-frequency TP and ADA. In addition, in view of the poor low-frequency performance of the FOG due to drift and noise that may result in the inaccuracy of the observed low-frequency disturbance, the FOG-based DOB was used to improve the relatively high-frequency ADA. The proposed method could make EOB and DOB complementary and help to obtain a high-precision MOTS, for in practical engineering, we give more attention to the low-frequency TP and full-band ADA. Simulations and experiments demonstrated that the proposed method was valid and had a much better performance than the traditional velocity and position double-loop control (VPDC).

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“…Generally, the tracking bandwidth and the disturbance suppression ability (DSA) are two key indicators of the FTOS. However, due to the low CCD sampling rate, time delay of image processing and the mechanical resonance of the platform, it is nearly impossible to acquire a wide bandwidth [ 6 , 7 ], so many scholars have focused on approaches to increase the DSA of the system. As the whole DSA is the product of the inner loop and outer position loop [ 8 ], Traditionally, the high sampling fiber-optic gyroscope (FOG) are added to the platform to build the velocity dual-loop control (VDLC) including position and velocity loops for the LOS stabilization [ 9 , 10 , 11 ].…”

Section: Introductionmentioning

confidence: 99%

Combining a Disturbance Observer with Triple-Loop Control Based on MEMS Accelerometers for Line-of-Sight Stabilization

Luo

Huang

Deng

et al. 2017

Sensors

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In the CCD-based fine tracking optical system (FTOS), the whole disturbance suppression ability (DSA) is the product of the inner loop and outer position loop. Traditionally, high sampling fiber-optic gyroscopes (FOGs) are added to the platform to stabilize the line-of-sight (LOS). However, because of the FOGs’ high cost and relatively big volume relative to the back narrow space of small rotating mirrors, we attempt in this work to utilize a cheaper and smaller micro-electro-mechanical system (MEMS) accelerometer to build the inner loop, replacing the FOG. Unfortunately, since accelerometers are susceptible to the low-frequency noise, according to the classical way of using accelerometers, the crucial low-frequency DSA of the system is insufficient. To solve this problem, in this paper, we propose an approach based on MEMS accelerometers combining disturbance observer (DOB) with triple-loop control (TLC) in which the composite velocity loop is built by acceleration integration and corrected by CCD. The DOB is firstly used to reform the platform, greatly improving the medium-frequency DSA. Then the composite velocity loop exchanges a part of medium-frequency performance for the low-frequency DSA. A detailed analysis and experiments verify the proposed method has a better DSA than the traditional way and could totally substitute FOG in the LOS stabilization.

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Combined line-of-sight error and angular position to generate feedforward control for a charge-coupled device–based tracking loop

Cited by 18 publications

References 11 publications

Delay-Compound-Compensation Control for Photoelectric Tracking System Based on Improved Smith Predictor Scheme

Delay-Compound-Compensation Control for Photoelectric Tracking System Based on Improved Smith Predictor Scheme

Feedforward Control Based on Error and Disturbance Observation for the CCD and Fiber-Optic Gyroscope-Based Mobile Optoelectronic Tracking System

Combining a Disturbance Observer with Triple-Loop Control Based on MEMS Accelerometers for Line-of-Sight Stabilization

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