Bismark C. Torrico

Robust Nonlinear Predictive Control Applied to a Solar Collector Field in a Solar Desalination Plant

This brief presents the application of a robust nonlinear predictive controller to the distributed collector field of a solar desalination plant. The main purpose of the controller is to manipulate the water flow rate to maintain the collector outlet-inlet temperature gradient constant in spite of disturbances. The controller uses a robust dead-time compensation structure and a nonlinear model predictive control to cope with time delay uncertainties and system nonlinearities, respectively. Simulation and real experimental results are shown to illustrate controller performance.

Filtered model-based predictive control applied to the temperature and humidity control of a neonatal incubator

This paper proposes a robust multivariable predictive control algorithm that improves the robustness of closed loop systems, even when they have multiple time delays between the inputs and outputs. The desired robustness is achieved by including an appropriate filter on the disturbances model. The proposed algorithm is applied to the control of humidity and temperature of a neonatal incubator. Simulation and experimental results show the advantages of the proposed algorithm compared to others proposed in the literature.

Simplified dead-time compensator for multiple delay SISO systems

This paper presents a dead-time compensation structure able to deal with stable and unstable multiple delay single input single output (SISO) systems. The proposed method aims to simplify the primary controller by replacing it for FIR filters placed at the feedback path. Such modification reduces the total number of parameters to be tuned which facilitates the overall design in comparison with other primary controllers normally considered. Simulation results show a better performance for the proposed control approach compared with other dead-time compensator (DTC) recently proposed in the literature.

Trajectory tracking control of a mobile robot using lidar sensor for position and orientation estimation

In this paper it is investigated the trajectory tracking control of a wheeled mobile robot using a laser rangefinder sensor to estimate the robot position and orientation (posture). This technique is compared with the conventional odometry method where the encoders data are used for posture estimation. The paper also presents the description of the robot as well as its mathematical modeling. Two controllers in cascade were used to implement the tracking control. A kinematics controller generates the references for internal motor speed controllers. Experimental results in an indoor environment are presented for trajectories with no obstacles.

Robust Control Based on Generalized Predictive Control Applied to Switched Reluctance Motor Current Loop

This paper proposes a robust control based on generalized predictive control (GPC) applied to the current control loop for a switched reluctance motor (SRM) drive. The proposed controller has two degrees of freedom where the setpoint tracking is decoupled from the load disturbance rejection at the nominal case. In addition a filter design is proposed in order to achieve good relationship among robustness, load disturbance rejection, and noise attenuation. Simulation and real experimental results are shown to illustrate the controller performance. [DOI: 10.1115/1.4026128]

Trajectory tracking control of a nonholonomic mobile robot with differential drive

This paper presents the development and trajectory tracking control of a nonholonomic mobile robot with differential drive. The used control system is composed of two loops cascaded, with internal PID controlling the speed of the two wheels and an external loop controlling the robot position and orientation. The second one is a feedfoward kinematics controller which is tuned according to desired closed-loop characteristics specified by the user. The control strategies were embedded in a digital module based in a 32-bit ARM microcontroller. In order to evaluate the performance of the developed robot, trajectory tracking tests were carried out for different trajectories and initial conditions. Preliminary experimental results are presented for reference trajectories without obstacles.

PI multivariable control applied to temperature and humidity neonate incubators

This paper proposes multivariable PI control strategies for humidity and temperature of neonate incubator loop This process is a TITO system (Two Input Two Output). The transfer function matrix was identified using closed loop step response through sequential method that decouples the TITO system into four independent loops. Models of three parameters were used for the system loops due to simplicity. Two methods of PI tuning were then developed for the loops of the incubator with the main objective of ensuring robustness and stability, namely: i) design of decentralized PI controller using the modified Ziegler-Nichols method and ii) BLT method (Biggest Log-Module Tuning) revised. Extensive experimental test were performed and some results are presented in the paper.

Anti-windup predictive current controller applied to a DFIG-based wind turbine under low DC-link voltage

During unsymmetrical/symmetrical voltage sags, there is a drop in the DC-link voltage, thus it can lead to serious impacts, i.e. current and power oscillations, to a double fed induction generator (DFIG) with a simplified power converter (rotor side converter with three-phase passive diode rectifiers). Therefore, this paper deals with an anti-windup predictive current controller applied to a DFIG-based wind turbine under low DC-link voltage condition. In order to investigate the transient overshoots and ripples that appear in the rotors current and DC-link voltage, several experimental tests are carried out. The test results shows the effectiveness of the proposed anti-windup predictive controller when it is compared to the PI controller.

Anti-windup dead-time compensation based on generalized predictive control

This work proposes an anti-windup dead-time compensator (DTC) based on a generalized predictive controller (GPC). At first, it is analysed the dead-time compensation properties of the GPC by its formulation in a DTC structure. Secondly, a saturation model is added in order to overcome windup problems. The proposed control structure does not use any extra tuning parameter due to the anti-windup characteristic. Simulation results are used to compare the proposed controller with others anti-windup DTCs proposed in literature.

Simplified filtered Smith predictor for MIMO processes with multiple time delays.

This paper proposes a simplified tuning strategy for the multivariable filtered Smith predictor. It is shown that offset-free control can be achieved with step references and disturbances regardless of the poles of the primary controller, i.e., integral action is not explicitly required. This strategy reduces the number of design parameters and simplifies tuning procedure because the implicit integrative poles are not considered for design purposes. The simplified approach can be used to design continuous-time or discrete-time controllers. Three case studies are used to illustrate the advantages of the proposed strategy if compared with the standard approach, which is based on the explicit integrative action.