A laboratory that supports research on control systems in Parana, Brazil

Alessandro N. Vargas

Labcontrol stands for a laboratory for research in control systems and automation at UTFPR Brazil. Labcontrol hosts advanced equipment to check new control strategies. This laboratory aims to provide conditions for which most of the control rules can be checked in practice. It is interesting because researchers can verify the effectiveness of their control methodologies in practice. The control strategy can be implemented in many hardware, such as in a PC running Matlab, Arduino, DSP, FPGA, Quanser board, Hardware-in-the-loop, etc.. ). This hardware is then connected physically to a process, i.e., the equipment to be controlled. We use a power amplifier in many of these experiments to make the interface between the acquisition card and plant. Below you can see some of the processes available in our laboratory facilities. All processes are functional and can be used at any time by anyone interested in doing research with us. If you have become interested in our laboratory, or if you want to check your control rule in practice, or if you want to start a cooperation with our group, send us a message at avargas@utfpr.edu.br

More about Labcontrol

Labcontrol is located at UTFPR, in the Cornelio Procopio Campus (in the urban area of Londrina, Parana, Brazil).

Figure 1: Skyline of Cornelio Procopio, Parana.

Figure 2: Photo of the outside face of the building that hosts the Laboratory (picture was taken when it was under construction in 2010).

Figure 3: Entrance hall and corridor of the Laboratory facilities.

Figure 4: The Laboratory occupies four rooms with 40 square meters each. This picture shows just only one of them.

Cooperation

We are open to national and international cooperation. If you have the interest to cooperate with us, please send us a message. We have established a fruitful collaboration with national and international Control Systems' groups. To support our communication, we use email and other new communication technologies. These tools allow us to work with colleagues anywhere in the world. Join us.

Some devices available in Labcontrol

Servomechanism

The servomechanism is based on the direct current DC Motor Module 2208, made up by DatapoolEletronica Ltda, Brazil, using a National Instruments USB-6008 data acquisition card to perform a physical link with the computer. The computer calls the Matlab software to implement the controller physically. Any control rule, such as linear, non-linear, time-varying, and so forth, can be implemented. Second-order linear systems can satisfactorily represent the DC motor. The two system state variables are the motor shaft's angular velocity and the electrical current consumed by the motor. The device has a sensor for both variables, which signifies that we can implement full-state feedback. To measure the angular velocity, we use the manufacturer-provided tachogenerator that produces a voltage proportional to the shaft; and to measure the electric current, we introduce in series with the motor a simple circuit composed by a shunt resistor connected with a pre-amplifier signal stage. First-order analog filters are used in the circuit to reduce high-frequency noise from the experimental data. The circuitry of the DC motor can be modified to accept failures. These failures can be either deterministic or stochastic. Hence one can check whether that theoretical control rule, derived for systems under failures, works in practice.

Figure 5: Servomechanism.

DC-DC buck converter

A buck converter is a voltage step down and current step up converter. In our lab, we have implemented an analog state-feedback control. In this experiment, all of the variables are continuous-time, i.e., there are no PC and data acquisition cards involved in the experiments.

Figure 6: DC-DC buck converter.

Two-coupled tanks

The two-coupled tanks are connected in such a way to generate a nonlinear control system with structural constraints. Matlab's equipment is fully controlled, and all of the sensors and actuators are driven by signals generated inside Matlab. The left figures show the functional block diagram, and the right one shows a picture of the equipment.

Figure 7: Two-coupled tanks.

Notice in the diagram that a pump takes water from the reservoir and put it in Tank 2. Another pump in Tank 2 takes the water therein to send it to Tank 1. But Tank 1 has a manual valve that keeps opened, and a flux of water flows from Tank 1 to the reservoir. We want to control the level of the Tanks 1 and 2. And the actuators are the pumps connected in the reservoir and Tank 2. This configuration is extremely challenging from the Control point of view.

Figure 7: Two-coupled tanks.

ECP System: Torsional Apparatus

This system represents a broad and essential class of practical plants, including rigid bodies, flexibility in drives, and coupled discrete vibrating systems. It quickly transforms into second, fourth, and sixth (optional) order plants with collocated or non-collocated sensor/actuator control, see Fig. 7. For more details, check it here: http://www.ecpsystems.com/controls_torplant.htm

Figure 6: ECP System: Torsional Apparatus.

Control Moment Gyroscope

ECP's four-axis Control Moment Gyroscope is a dynamically rich system that provides superb demonstrations of multi-DOF rigid body control. For more details, check it here: http://www.ecpsystems.com/controls_ctrlgyro.htm

Figure 7: Control Moment Gyroscope.