Posicast Control of Damped Oscillatory Systems

Smith, Otto J. M.

doi:10.1109/jrproc.1957.278530

Cited by 483 publications

(223 citation statements)

References 3 publications

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“…which compensates any oscillation immediately after applying the last impulse ( [1]). By convolving this sequence with any desired command signal, new control inputs are generated which move the system without vibration.…”

Section: Input Shapingmentioning

confidence: 99%

“…When applying the whole sequence (3) as an input to (1), then the response is the convolution result of (3) with (4). This can be understood as a linear combination of the delayed signals y(t − t i ).…”

Section: Input Shapingmentioning

confidence: 99%

“…Let e(t) be the control error observed when a shaped unit step is applied to (1). Using (28), the shaped response will be:…”

Section: Quadratic Control Error Minimizationmentioning

confidence: 99%

“…It consists of generating commands that move the system without vibration using some pre-knowledges about the plant. Smith [1] presented 1957 the posicast control as a first form of input shaping. It consists in generating two transient oscillations which cancel each other and lead to a non-oscillatory response.…”

Section: Introductionmentioning

confidence: 99%

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New aspects of input shaping control to damp oscillations of a compliant force sensor

Kamel

Lange

Hirzinger

2008

2008 IEEE International Conference on Robotics and Automation

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Abstract-Compliance in robot mounted force/torque sensors is useful for soft mating of parts. However it generates nearly undamped oscillations when moving the end-effector in free space. In this paper, input shaping control is investigated to damp such unwanted flexible modes. We present a new design technique that creates long impulse sequences to adapt input shaping to systems with long sampling period and to compensate the resulting time delay. This makes the method feasible for industrial robots. In addition to the conventional input shaping which causes oscillations to stop only after applying the last impulse, we also minimize the quadratic control error until this time step is reached.

show abstract

Section: Input Shapingmentioning

confidence: 99%

Section: Input Shapingmentioning

confidence: 99%

“…Let e(t) be the control error observed when a shaped unit step is applied to (1). Using (28), the shaped response will be:…”

Section: Quadratic Control Error Minimizationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

New aspects of input shaping control to damp oscillations of a compliant force sensor

Kamel

Lange

Hirzinger

2008

2008 IEEE International Conference on Robotics and Automation

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“…To achieve desired performance, the motion profile should be shaped by input shaper. Input shaper [16], one kind of feedforward controllers, shapes the reference input signal based on the characteristics of the controlled system. It consists of two or more groups of signals with different amplitudes and delay times.…”

Section: Introductionmentioning

confidence: 99%

Online‐Offline Optimized Motion Profile for High‐Dynamic Positioning of Ultraprecision Dual Stage

2018

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The wafer stage in dual-stage lithographic system is an air-bearing servo motion platform requiring high positioning accuracy and high transient performance. However, the residual vibration, resulting from almost zero damping, high velocity, parallel decoupling structure, and direct drive, brings about unacceptable overshoot and settling time. To suppress these unfavorable elements in high dynamic motion, a novel motion profile planning method combined with input shaping is proposed in this paper. Firstly, a trajectory named all free S-curve (AFS-curve) is derived, which has less constraints and better performance than traditional S-curve profile. Then, AFS-curve combined with a zero vibration shaper (ZV) is developed to further suppress residual vibration. Due to the very complex parameter adjustment, the online tuning may cause system oscillation that leads to damage of the precision stage. This paper, furthermore, proposes an online-offline method to optimize the parameters in the motion profile. Online step is performed to collect input and output data. Offline step includes the system model identification based on I/O data and parameter self-learning based on particle swarm optimization (PSO). The simulation and experimental results indicate that the proposed method achieves significant reduction of the positioning time and the overshoot in the dual-stage system.

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Control for Time‐Varying Delay Systems by Integrating Semi‐Discretization and Hysteresis‐Based Switching

Shao

Li³

et al. 2018

Asian Journal of Control

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In this paper, we develop an innovative control method for linear systems with time‐varying delay by integrating the semi‐discretization method and the hysteresis‐based switching algorithm. The semi‐discretization method is adopted to design an optimal controller for each fixed time‐delay and form a candidate controller family. The switching algorithm acts as the principal law for switching among various controllers according to the instantaneous value of the time‐delay. A theoretical proof is presented regarding the stability of the switching time‐delay system. It is shown that the most significant factors that affect the system stability are the size of the candidate controller family, the value of the switching coefficient, and the changing rate of the time‐delay. Two case studies are presented to show the effectiveness of the proposed method.

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Posicast Control of Damped Oscillatory Systems

Cited by 483 publications

References 3 publications

New aspects of input shaping control to damp oscillations of a compliant force sensor

New aspects of input shaping control to damp oscillations of a compliant force sensor

Online‐Offline Optimized Motion Profile for High‐Dynamic Positioning of Ultraprecision Dual Stage

Control for Time‐Varying Delay Systems by Integrating Semi‐Discretization and Hysteresis‐Based Switching

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