A Dynamic Sliding Mode Controller Approach for Open-Loop Unstable Systems

Camacho, Christian; Camacho, Oscar

doi:10.1109/ropec55836.2022.10018798

Cited by 4 publications

(3 citation statements)

References 11 publications

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“…It would also be interesting to compare the disturbance observer in automatic reset controllers with the state-space approach [48], with active disturbance rejection control (ADRC) solutions [71][72][73][74][75], or with intelligent PID using finite impulse response filters (FIR) to reconstruct disturbances [76]. Robust control of constrained systems is also solved using sliding mode control (SMC) [77][78][79][80][81][82][83], in which permanent oscillations can be deliberately imposed on the circuit, reminding constrained PIDA controllers with more aggressive settings. Similarly, comparisons with recent modifications of the Smith predictor would also be interesting [84,85].…”

Section: Discussionmentioning

confidence: 99%

Parametrization and Optimal Tuning of Constrained Series PIDA Controller for IPDT Models

Huba,

Bistak,

Vrancic

2023

Mathematics

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The new modular approach to constrained control of higher-order processes with dominant first-order dynamics using generalized controllers with automatic resets (ARCs) is addressed. The controller design is based on the multiple real dominant pole (MRDP) method for the integrator plus dead time (IPDT) process models. The controller output constraints are taken into account by inserting the smallest numerator time constant of the controller transfer function into the positive feedback loop representing the automatic reset (integral) term. In the series realization of the proportional–integral–derivative–acceleration (PIDA) controller (and other controllers with even derivative degree), the time constant mentioned is complex, so only the real part of the time constant has been used so far. Other possible conversions of a complex number to a real number, such as the absolute value (modulus), can be covered by introducing a tuning parameter that modifies the calculated real time constant and generalizes the mentioned conversion when designing controllers with constraints. In this article, the impact of the tuning parameter on the overall dynamics of the control loop is studied by simulation. In addition, an evaluation of the stability of the closed-loop control system is performed using the circle criterion in the frequency domain. The analysis has shown that the approximation of the complex zero by its real part and modulus leads to a near optimal response to the set point tracking. The disturbance rejection can be significantly improved by increasing the tuning parameter by nearly 50%. In general, the tuning parameter can be used to find a compromise between servo and regulatory control. The robustness and applicability of the proposed controller is evaluated using a time-delayed process with first-order dominant dynamics when the actual transfer function is much more complicated than the IPDT model. A comparison of the proposed MRDP-PIDA controller with series PI, PID and PIDA controllers based on a modified SIMC method has shown that the MRDP-PIDA controller performs better than the SIMC method, although the SIMC uses a more complex process model.

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Section: Discussionmentioning

confidence: 99%

Parametrization and Optimal Tuning of Constrained Series PIDA Controller for IPDT Models

Huba,

Bistak,

Vrancic

2023

Mathematics

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“…The decrease in I AE values when the derivative degree (m) in the controllers is increased is associated with an increase in TV 1 (u) values. However, it should be recalled that robust controllers are often implemented as sliding mode control (SMC) [68][69][70][71][72], where the control signal is constantly oscillating, which can lead to a sharp increase in TV 1 (u).…”

Section: Robustness Versus Excessive Control Effortmentioning

confidence: 99%

IPDT Model-Based Ziegler–Nichols Tuning Generalized to Controllers with Higher-Order Derivatives

Bisták

Huba

Vrančić

et al. 2023

Sensors

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The paper extends the earlier work entitled “Making the PI and PID Controller Tuning Inspired by Ziegler and Nichols Precise and Reliable”, to higher-order controllers and a broader range of experiments. The original series PI and PID controllers, based on automatic reset calculated by filtered controller outputs, are now augmented by higher-order output derivatives. This increases the number of degrees of freedom that can be used to modify the resulting dynamics, accelerates transient responses, and increases robustness to unmodeled dynamics and uncertainties. The fourth order noise attenuation filter used in the original work allows for the addition of an acceleration feedback signal, thus resulting in a series PIDA controller or even a jerk feedback that leads to a PIDAJ series controller. Such a design can further use the original process and filter approximation of the step responses through the integral-plus-dead-time (IPDT) model, while allowing experimentation with disturbance and setpoint step responses of the series PI, PID, PIDA and PIDAJ controllers, and thus, evaluating the role of output derivatives and noise attenuation from a broader perspective. All controllers considered are tuned using the Multiple Real Dominant Pole (MRDP) method, which is complemented by a factorization of the controller transfer functions to achieve the smallest possible time constant for automatic reset. The smallest time constant is chosen to improve the constrained transient response of the considered controller types. The obtained excellent performance and robustness allow the proposed controllers to be applied to a wider range of systems with dominant first-order dynamics. The proposed design is illustrated on a real-time speed control of a stable direct-current (DC) motor, which is approximated (together with a noise attenuation filter) by an IPDT model. The transient responses obtained are nearly time-optimal, with control signal limitations active for most setpoint step responses. Four controllers with different degrees of derivative with generalized automatic reset were used for comparison. It was found that controllers with higher-order derivatives may significantly improve the disturbance performance and virtually eliminate overshoots in the setpoint step responses in constrained velocity control.

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“…DSMC has been employed in open-loop self-regulating systems [4,[13][14][15][16], and some works report the application of SMC to open-loop unstable systems [17][18][19][20][21][22][23]. However, to the author's knowledge, there are only a small number of reported studies on the application of DSMC to open-loop non-self-regulating systems processes [24,25]. Controlling open-loop non-self-regulating processes has significant challenges, even more so if they have a time delay, which further complicates the control.…”

Section: Introductionmentioning

confidence: 99%

An Internal Model Based—Sliding Mode Control for Open-Loop Unstable Chemical Processes with Time Delay

et al. 2023

Self Cite

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This paper presents a dynamic sliding mode control (DSMC) for open-loop unstable chemical or biochemical processes with a time delay. The controller is based on the sliding mode and internal model control concepts. The proposed DSMC has an internal P/PD controller to provide systems with disturbance rejection. An identification method approximates the open-loop unstable nonlinear process to a first-order delayed unstable process (FODUP). The reduced-order model(FODUP) is used to synthesize the new controller. The performance of the controller is stable and satisfactory despite nonlinearities in the operating conditions due to set-point and process disturbance changes. In addition, the performance analysis of the control schemes was evaluated based on various indices and transient characteristics, including the integral of squared error (ISE), the total variation of control effort (TVu), the maximum overshoot (Mp), and the settling time (ts). Finally, the process output and the control action for all controllers are compared using the nonlinear process as the real plant.

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A Dynamic Sliding Mode Controller Approach for Open-Loop Unstable Systems

Cited by 4 publications

References 11 publications

Parametrization and Optimal Tuning of Constrained Series PIDA Controller for IPDT Models

Parametrization and Optimal Tuning of Constrained Series PIDA Controller for IPDT Models

IPDT Model-Based Ziegler–Nichols Tuning Generalized to Controllers with Higher-Order Derivatives

An Internal Model Based—Sliding Mode Control for Open-Loop Unstable Chemical Processes with Time Delay

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