Current-sensorless robust sliding mode control for the DC-DC boost converter

A current-sensorless PWM-based robust sliding mode controller is proposed for the DC-DC Boost Converter, a nonminimum phase system that presents major challenges in the design of stabilizing controllers. The development of the controller requires the measurement of the output voltage and the estimation of its derivative. An extended state observer is developed to estimate a lumped uncertainty that comprises the uncertain load and input voltage, the converter parasitics, the component uncertainties and also to estimate the derivative of the output voltage. A linear sliding surface is used to derive the controller that is simple in its design and yet exhibits excellent features in term of robustness to external disturbances, parameter uncertainties and parasitics and despite the absence of the inductor current feedback. Also, a simple procedure to select the controller gains is developed. The robustness of the controller is validated by computer simulations. Future work will be the validation of these results experimentally.

This paper proposes a novel composite dual-control by combing the integral sliding mode control (ISMC) method based on the finite time convergence theory with extended state observer (ESO) for a tracking problem of a missile with tail fins and reaction-jet control system (RCS). First, the ISMC method based on finite time convergence is utilized to design the control law of tail fins and the pulse control of RCS for the dual-control system, ensuring the system with rapid response and high accuracy of tracking. Then, ESO is employed for the estimation of aerodynamic disturbances influenced by the airflow of thruster jets. With the characteristic of high accuracy estimation of ESO, the chattering free tracking performance of the attack angle command and the robustness of the control law are achieved. Meanwhile, the stability of the dual-control system is analyzed based on finite time convergence stability theorem and Lyapunov's theorem. Finally, numerical simulations demonstrate the effectiveness of the proposed design.

Perturbation observer based fractional-order sliding-mode controller for MPPT of grid-connected PV inverters: Design and real-time implementation

An adaptive robust variable structure speed controller is designed for wide range of desired velocity control of a Permanent Magnet Linear Synchronous Motor (PMLSM). This is performed for comprehensive nonlinear model of PMLSM including non-idealities such as detent force, parameter uncertainty, unpredicted disturbance and nonlinear friction. The proposed method is based on the robust Sliding Mode Control (SMC) in combination with an adaptive strategy for a wide range of velocity. The simulation results are provided for the above mentioned comprehensive model of PMLSM with a variable velocity profile. Moreover, as an evaluation criterion, a Proportional-Integral (PI) controller is designed whose parameters are optimally tuned by the Particle Swarm Optimization (PSO) algorithm for better comparison.

Electric motors have been widely used as the actuators of robot and automation systems. This paper aims at achieving the high-precision position control of motor drive systems. For this purpose, a robust control scheme is presented by combining the internal model principle, the sliding mode technique and the extended state observer (ESO). The PID-type controller is firstly designed by using the internal model control (IMC) rules. Since the analysis of the IMC system is performed via a sliding surface, a robust sliding mode control (SMC) law is then synthesized to enhance the control ability of the system to uncertainties. However, this robust solution should make a trade-off between the chattering attenuation and the control accuracy. To handle this drawback, a linear ESO is employed to compensate the modeling errors for a higher control accuracy. The stability analysis is provided via a Lyapunov-based method, and the superiority of the proposed approach was validated by comparative experiments on a motor drive platform.

This paper focuses on the high-performance bidirectional DC-DC converter required in distributed electric propulsion (DEP) systems, with the dual active bridge (DAB) converter chosen as the subject of study. To achieve the goal of stabilizing the output voltage while improving the converter’s anti-interference ability and dynamic performance, this paper proposes a novel strategy. In particular, it combines the Linear Extended State Observer (LESO) with a sliding mode control (SMC), proposing a sliding mode control strategy based on the Linear Extended State Observer (LESO-SMC). Notably, this control strategy not only retains the fast dynamic performance of Linear Active Disturbance Rejection Control (LADRC) and the robustness of SMC but also addresses the significant chattering issue inherent in traditional SMC. Comparing the traditional PI, LADRC, and SMC strategies, the results show that when the load changes, the voltage fluctuation of the LESO-SMC strategy proposed in this paper is 0.165 V (0.25 V) in the Matlab/Simulink and RT-Lab platforms, and the average adjustment time is 4 ms (3.5 ms). In contrast, the average voltage fluctuations of PI and LADRC strategies were 3.7 V (4.9 V) and 0.55 V (1.35 V), and the average adjustment times were 99.5 ms (201 ms) and 71.5 ms (77.5 ms), respectively. When the input voltage changes, the proposed LESO-SMC strategy adjusts faster and has almost no voltage fluctuations, while the average voltage fluctuations of the PI and LADRC strategies in the simulation are 0.5 V and 0.1 V, and the average adjustment times are 89.5 ms and 35 ms, and the change in the input voltage in the RT-Lab platform has very little effect on the output voltage. Compared with SMC, the LESO-SMC strategy has no chattering problem. In summary, compared to the other three control strategies, the LESO-SMC strategy proposed in this paper exhibits superior performance in terms of voltage fluctuation and adjustment time during load changes and input voltage changes. It shows a robust anti-interference ability and a rapid dynamic response performance.

During the underwater directional operation of the atmospheric diving suit (ADS), the ADS system encounters problems caused by external disturbances, parameter uncertainties and time-varying terms. To solve these problems, an ADS course controller is proposed based on adaptive sliding mode control with extended state observer (ESO). The ESO can effectively estimate the disturbances in order to realize compensation, while the adaptive sliding mode controller has good robustness and enables further compensation. The designing process of the ADS course controller is described in detail in this paper. The system stability and convergence are proved using the Lyapunov stability criterion and are testified through simulation experiments. Simulation results show that the proposed controller has good robustness and achieves satisfying performance in ADS course control.

Interleaved dc-dc boost converter (IBC) has been widely used in the fuel cell applications, due to the features of low current ripple, high efficiency and high reliability. In this paper, a voltage controller based on the extended state observer (ESO) is proposed for this converter, aiming to deal with the parameter uncertainties and the external disturbances (including the input voltage perturbation and load current disturbance). Within the proposed control, the uncertainties and disturbances are treated as the lump disturbance, which is estimated by the ESO and is then canceled in the control action in real time. The proposed controller shows strong robustness against the uncertainties and external disturbances, which is demonstrated by both the simulation and experiment results.

This paper proposes an active disturbance rejection adaptive controller for tracking control of a class of uncertain nonlinear systems with consideration of both parametric uncertainties and uncertain nonlinearities by effectively integrating adaptive control with extended state observer via backstepping method. Parametric uncertainties are handled by the synthesized adaptive law and the remaining uncertainties are estimated by extended state observer and then compensated in a feedforward way. Moreover, both matched uncertainties and unmatched uncertainties can be estimated by constructing an extended state observer for each channel of the considered nonlinear plant. Since parametric uncertainties can be reduced by parameter adaptation, the learning burden of extended state observer is much reduced. Consequently, high-gain feedback is avoided and improved tracking performance can be expected. The proposed controller theoretically guarantees a prescribed transient tracking performance and final tracking accuracy in general while achieving asymptotic tracking when the uncertain nonlinearities are not time-variant. The motion control of a motor-driven robot manipulator is investigated as an application example with some suitable modifications and improvements, and comparative simulation results are obtained to verify the high tracking performance nature of the proposed control strategy.

This paper presents a robust sliding mode controller of DC-DC buck converter for renewable energy applications, such as photovoltaic systems in off-grid configurations. Photovoltaic systems in off-grid configuration are exposed to significant variations in input voltage and power loads. The proposed sliding mode controller presents a simple and efficient method of continuously updating the duty cycle of a pulse width modulation unit (PWM) of a buck converter. The PWM unit is operated at constant switching frequency of 10 kHz carrier signal and varying duty cycle. The differences in input voltage and power load are treated as two bounded uncertainties, thus eliminating the need for input voltage sensor and output current sensors leaving the system with a single sensor required to measure the converter output voltage. That is, measured output voltage is compared with the reference voltage to continuously update the average duty cycle value of PWM unit. Adjustment of PWM duty cycle is performed while maintaining the sliding condition always fulfilled. The simulation results of the proposed controller showed robustness and accuracy against power load fluctuation, changes in desired output voltage, and variations in the input supply voltage that may result from the varying level of irradiance and temperature.

SummaryThis article investigates the precise motion control of multi‐degrees of freedom (DoF) hydraulic manipulators, and proposes an active disturbance rejection adaptive control (ADRAC) architecture based on full state feedback with consideration of both unmatched and matched uncertainties, that is, parametric uncertainties and uncertain nonlinearities. The new control strategy integrates adaptive control with extended state observer (ESO) via the backstepping method. Parametric uncertainties are handled by the synthesized adaptive law, and ESO is designed to estimate the remaining uncertainties before being compensated in a feedforward way. In particular, the unmatched and matched uncertainties can be observed in real‐time by constructing an ESO for each channel of the hydraulic manipulator system. The burden on ESO should be greatly reduced since parameter adaptation offsets most parametric uncertainties. Accordingly, high‐gain feedback is avoided in the resulting controller, and improved servo performance can thus be expected. In theory, the suggested ADRAC controller can attain asymptotic tracking performance under the influence of not only parametric uncertainties derived from various hydraulic parameters but also invariant disturbances. Furthermore, when uncertain nonlinearities become time‐variant, prescribed transient tracking performance and final tracking accuracy can also be ensured. Comparative simulations concerning both matched and unmatched uncertainties are obtained to illustrate the high tracking performance nature of the developed control algorithm.

This paper presents an active disturbance rejection adaptive control scheme via full state feedback for motion control of hydraulic servo systems subjected to both parametric uncertainties and uncertain nonlinearities. The proposed controller is derived by effectively integrating adaptive control with extended state observer via backstepping method. The adaptive law is synthesized to handle parametric uncertainties and the remaining uncertainties are estimated by the extended state observer and then compensated in a feedforward way. The unique features of the proposed controller are that not only the matched uncertainties but also unmatched uncertainties are estimated by constructing two extended state observers, and the parameter adaptation law is driven by both tracking errors and state estimation errors. Since the majority of parametric uncertainties can be reduced by the parameter adaptation, the task of the extended state observer is much alleviated. Consequently, high-gain feedback is avoided and improved tracking performance can be expected. The proposed controller theoretically achieves an asymptotic tracking performance in the presence of parametric uncertainties and constant disturbances. In addition, prescribed transient tracking performance and final tracking accuracy can also be guaranteed when existing time-variant uncertain nonlinearities. Comparative experimental results are obtained to verify the high tracking performance nature of the proposed control strategy.

We propose an extended-state-observer (ESO)-based robust position tracking control method using nonlinear damping gain to improve the control performance under external disturbances and parameter uncertainties for quadrotors. The proposed method consists of an ESO and a nonlinear damping controller (NDC). The ESO is designed to estimate full state and disturbance. The external disturbance, velocity dynamics, and the uncertainty of the input parameter are lumped in the disturbance. The NDC is developed via backstepping procedure to suppress the output tracking error according to the disturbance estimation error. The proposed method is simple and robust against external disturbance and parameter uncertainties. In addition, only the nominal value of the input gain parameters are required. The closed-loop stability is proven by using the input-to-state stability property. The position tracking performance of proposed method was verified by performing hardware-in-the-loop simulations using a quadrotor platform.

This paper addresses the design and application controller for a small-size unmanned aerial vehicle. A new robust sliding mode controller (SMC) is proposed to improve the performance under internal model uncertainty and external disturbance conditions. To precisely control the attitude and position, a new SMC based on the backstepping technique is formulated to guarantee the attitude system stability. To implement this controller, an extended state observer is used to estimate the unmeasurable states and external disturbances. Moreover, a new sliding mode control method with the backstepping technique is applied to ensure that the position system is stable. In addition, the Lyapunov theory demonstrates the stability of the attitude and position loops. Finally, the numerical experimental flight results are provided to illustrate the effectiveness and robustness of the proposed controller.

This paper presents methodologies for design and experimental evaluation of both Proportional Integral and Derivative (PID) and Extended State Observer (ESO) controller for auto landing system. The process of auto landing can be experimentally described as second-order model for ESO controller. A PID controller and ESO controller is proposed to achieve the desired response for the autoland system. Computer simulations are performed to illustrate the performance of PID and ESO controller in comparison to each other. The applicability and usefulness of the proposed control scheme are well exemplified by conducting experiments on an aircraft model. Both simulations and experimental results reveal that the proposed PID and ESO scheme performs equally.