Laboratory Experiments > Tandem Pendulum > Brief Description

PC60 Tandem Pendulum

The laboratory experimental setup “Tandem Pendulum” contains the technical realization of an unstable, complex plant together with an actuator and a digital controller. The digital controller realizes an observer based state feedback controller. The laboratory setup is based on the plant “Position Control PC60”.

The basic system includes an actuator as well as the mechanical setup (PC60) with a premounted tandem pendulum extension kit (Option 60-40). The plant is represented by two revolving pendulums with different lengths mounted on top of a moving base. One pendulum (length 50 cm) is mounted on a sleeve shaft. An inner shaft is fixed to the second pendulum (length 10 cm). Both pendulums are pivoted independently from each other. By a three-phase synchronous drive, a toothed wheel, a toothed belt and a clutch, the moving base can be driven along a guiding bar over a length of approximately 1.5m such that both pendulums are stabilized in upright positions at a preassigned position. The stabilization of the pendulums is accomplished by a digital controller. Based on measurements, the controller generates a suitable signal which controls the integrated electronics of the synchronous drive. The measurements are the pendulum angles and the cart position obtained by incremental encoders. The documentation includes sections for assembly and start-up, the technical data, the program operation, the theoretical background with the mathematical model of the plant.

The standard digital control of the basic system consists of the PC adapter card MF634 Option 60-03 and an executable controller program (MS- Windows) Option 60-42. The adapter card as well as the program require a PC with PCIe slot.

The controller program (WINDOWS 7-10) is driven by pull-down menus. The control algorithm realizes a state feedback with estimation of the angular velocities of the pendulums and the speed of the cart as well as a disturbance observer to compensate the effects of the friction. The friction compensation force acts on the bearing of the cart. All of the controller and observer parameters are comfortable adjustable. The controller performance is examined by recording the measurements and observed signals of the system.

The graphic output of recorded data may be sent to a window. Its content may be printed, saved as a WMF file or copied into the clipboard.

Additional options extend the version of the laboratory setup described above to support research studies in the field of arbitrary control algorithms or applied fault detection methods. For this purpose the ‘C++’ source files of the programs are available.

By means of the PC plug-in card MF634 of Humusoft the laboratory experiment "PC60 Tandem Pendulum" can easily be integrated in Matlab/Simulink with real-time environment. The user now has the opportunity to test its own controller designs under Matlab/Simulink.

The Option 60-45 contains the C++ source files of the PC controller program including library functions for graphic output, controlling the sampling period as well as controlling the PC adapter card. With this option the user is able to implement special algorithms for control, supervision or fault detection in the frame of the menu-driven program. The Embarcadero C++ Builder V10 is required to generate an executable program.

Technical data are subject to change (Date 4-December-2017)