On Active Disturbance Rejection Based Control Design for Supercomputing RF Cavities

Superconducting RF (SRF) cavities are key components of modern linear particle accelerators. The National Superconducting Cyclotron Laboratory (NSCL) is building a 3 MeV/u re-accelerator (ReA3) using SRF cavities. Lightly loaded SRF cavities have very small bandwidths (high Q) making them very sensitive to mechanical perturbations whether external or self-induced. Additionally, some cavity types exhibit mechanical responses to perturbations that lead to high-order non-stationary transfer functions resulting in very complex control problems. A control system that can adapt to the changing perturbing conditions and transfer functions of these systems would be ideal. This paper describes the application of a control technique known as “Active Disturbance Rejection Control” (ARDC) to this problem

On Active Disturbance Rejection Based Control Design for Supercomputing RF Cavities

Superconducting RF (SRF) cavities are key components of modern linear particle accelerators. The National Superconducting Cyclotron Laboratory (NSCL) is building a 3 MeV/u re-accelerator (ReA3) using SRF cavities. Lightly loaded SRF cavities have very small bandwidths (high Q) making them very sensitive to mechanical perturbations whether external or self-induced. Additionally, some cavity types exhibit mechanical responses to perturbations that lead to high-order non-stationary transfer functions resulting in very complex control problems. A control system that can adapt to the changing perturbing conditions and transfer functions of these systems would be ideal. This paper describes the application of a control technique known as “Active Disturbance Rejection Control” (ARDC) to this problem

On active disturbance rejection based control design for superconducting RF cavities

Superconducting RF (SRF) cavities are key components of modern linear particle accelerators. The National Superconducting Cyclotron Laboratory (NSCL) is building a 3 MeV/u re-accelerator (ReA3) using SRF cavities. Lightly loaded SRF cavities have very small bandwidths (high Q) making them very sensitive to mechanical perturbations whether external or self-induced. Additionally, some cavity types exhibit mechanical responses to perturbations that lead to high-order non-stationary transfer functions resulting in very complex control problems. A control system that can adapt to the changing perturbing conditions and transfer functions of these systems would be ideal. This paper describes the application of a control technique known as “Active Disturbance Rejection Control” (ARDC) to this problem

On Active Disturbance Rejection for Systems with Input Time-Delays and Unknown Dynamics

This paper concerns with the typical problem of disturbance rejection in process control in the presence of time-delays and, possibly, the integrating or unstable dynamics. It is shown how unknown disturbance can be rejected actively in the absence of detailed mathematical model of the process. Disturbance rejection ability and stability are analyzed using the language of frequency response engineers are familiar with and, for the sake of simplicity, the discussion is limited to the first-order plus time delay (FOPTD) systems. The concept of delay margin is proposed to facilitate engineering design. A chemical reactor concentration control problem is used to provide the insight of this particular disturbance rejection strategy. Comparative simulation study shows a substantial improvement in the performance over a couple of existing methods seen recently in the literature

La Atalaya : diario de la mañana: Año XIII Número 4834 - 1905 mayo 7

Copia digital. Madrid : Ministerio de Educación, Cultura y Deporte. Subdirección General de Coordinación Bibliotecaria, 201

On Observer-Based Active Vibration Control of Two-Inertia Systems

The two-inertial system is a typical motion control problem with compliance between the motor and load, where the resonance makes it very challenging to regulate the load response and stabilize the motor at the same time. Concerned with setpoint tracking, disturbance rejection, and internal stability, an observer based Active Vibration Control solution is formulated, tested and analyzed in this paper. Simulation results show that the proposed method is an effective solution in obtaining desirable responses from both the motor and the load sides simultaneously. Furthermore, the controller is easy to implement and to tune, with much tolerance of internal dynamic variations and external disturbances. Finally, comparing with the existing solutions, the wear and tear of motors and transmission is much reduced

On Active Disturbance Rejection for Systems with Input Time-Delays and Unknown Dynamics

This paper concerns with the typical problem of disturbance rejection in process control in the presence of time-delays and, possibly, the integrating or unstable dynamics. It is shown how unknown disturbance can be rejected actively in the absence of detailed mathematical model of the process. Disturbance rejection ability and stability are analyzed using the language of frequency response engineers are familiar with and, for the sake of simplicity, the discussion is limited to the first-order plus time delay (FOPTD) systems. The concept of delay margin is proposed to facilitate engineering design. A chemical reactor concentration control problem is used to provide the insight of this particular disturbance rejection strategy. Comparative simulation study shows a substantial improvement in the performance over a couple of existing methods seen recently in the literature

On Combining Active Disturbance Rejection with Adaptive Inverse Control for Fast Tracking at Low Bandwidth

An adaptive feedforward mechanism is combined with active disturbance rejection control (ADRC) to provide fast tracking performance without requiring high observer bandwidth. The feedforward controller uses an inverse plant model that is continuously adjusted as the plant changes. Providing this controller with reasonable initial conditions dramatically improves how quickly it can derive a reasonable inverse model. Simulation results demonstrate tracking and disturbance rejection capabilities at a low cost, i.e. bandwidth

On Combining Active Disturbance Rejection with Adaptive Inverse Control for Fast Tracking at Low Bandwidth

An adaptive feedforward mechanism is combined with active disturbance rejection control (ADRC) to provide fast tracking performance without requiring high observer bandwidth. The feedforward controller uses an inverse plant model that is continuously adjusted as the plant changes. Providing this controller with reasonable initial conditions dramatically improves how quickly it can derive a reasonable inverse model. Simulation results demonstrate tracking and disturbance rejection capabilities at a low cost, i.e. bandwidth

On Active Vibration Suppression of a Piezoelectric Beam

Piezoelectric beam\u27s dynamics are characterized by elastic properties, nonlinearities, uncertain dynamics and unknown disturbances, making it a challenging control problem. In this paper, a method of Active Disturbance Rejection Control (ADRC) for piezoelectric beam control is proposed. Unique to this approach, the complex piezoelectric beam dynamics, known or unknown, linear or nonlinear, and all external disturbances are treated in their totality as an input disturbance, and is subsequently estimated and canceled. Simulation and experimental results in this paper demonstrate the significant advancement of the ADRC as an easier, simpler and better control method that is ready to be deployed in practice