Dep. Matemàtica Aplicada III
The objective of the laboratory is to have small scale setups exhibiting some challenging dynamic features to motivate theoretical work in modelling, identification and control. Furthermore, the theoretical results can be validated experimentally.
In the near future a new setup with a real throttle will be incorporated to the laboratory.
Electronic Throttle Control (ETC) is an automobile technology that severs the mechanical link between the accelerator pedal and the throttle. The Electronic Control Unit (ECU) determines the required throttle position in order to satisfy the driver torque demand depending on accelerator pedal position, engine speed, vehicle speed, etc. The electric motor within the ETC is then driven to the required position via a closed-loop control algorithm within the ECU. As the engine management system of modern vehicles relies heavily on the performance of this servomechanism, the underlying control system must be efficient, robust and easily tunable.
We are working in developing identification tools for hysteresis models used to describe base isolation devices and magnethoreological actuators. The identification tools will be validated using the shaking table to produce prescribed excitation inputs and measuring output displacement by a laser sensor.
We also work in developing active and semiactive nonlinear controllers for vibration mitigation.
The main feature of this system is the presence of friction. We are dealing with model identification and with the formulation of controllers for precision positioning.
INVERTED PENDULUM WITH BACKLASH
H infinity control design is studied for mechanisms with backlash. An output feedback controller has been implemented to stabilize the inverted pendulum with backlash, observing good performance.
See the video to observe the stabilized pendulum under control.
Developing of basic chaotic systems is a topic in the world of nonlinear dynamics. Applications of chaos have become important in many fields on communications, among others. At this respect, the CODALAB team is working on chaotic oscillators using PIC Microcontrollers.
A chaotic attractor.
A circuit implementation using a PIC Microcontroller.
The Structural Health Monitoring laboratory of the CoDAlab group is a modular laboratory that include the use of equipment from different companies which can be reconfigured according to the experimental mockup with different structures using piezoelectric transducers, the acquisition of the elements was supported by the ”Ministerio de Ciencia e Innovación” of Spain through the coordinated research project DPI2008-06564-C02-01/02. In general way, the SHM laboratory (figure 1) contains:
1) A National Instruments chassis (NI-PXI 1033): This chassis contains 5 slots, each slot allows to add National instruments cards, for instance: wave generators, acquisition, switches and other elements. The chassis can be connected with a computer using the PXI port by an express card.
2) A NI PXI-5114 card, it is a 8-bit Digitizer/oscilloscope of 250MS/s with 40mV to 40V input ranges.
3) A card NI PXI-5412, it is a arbitrary waveform generator with 14-bit resolution and 100 MS/s sampling rate.
4) A Crosspoint Matrix Switch card. Using this card it is possible to define until 4 x 32 matrix configuration. It is useful because depending of size of the structure and the number of sensors it is possible to reconfigure the number of terminals.
5) A wideband power amplifier to amplify the generated signals .
6) A laptop, to connect the chassis and to develop algorithms for acquisition and processing data.
7) A shelf to hang-up the elements to test.
The general idea for the methodology to apply in each experiment is:
1. The instrumented structure is suspended to isolate it from environment disturbances using elastic ropes.
2. By means of the switch module, one of the whole set of PZTs attached on the surface of the structure is chosen as actuator.
3. A known excitation signal generated by the NI-generator card is applied to the structure (vibrational input) by means of the actuator.
4. Vibrational responses at different points are recorded by using the rest of PZTs (sensors) and the digitizer card.
5. Actuator and sensors are changed using the switch module, and the steps 2 to 4 are repeated. These changes and repetitions are automatically applied by the algorithm developed in Labview.
6. Data in text based format is saved and organized.
7. Some damages are simulated and/or generated. Steps 2 until 6 are repeated.
8. Apply the strategy based on PCA to compare the vibrational responses of the current and healthy structures.