Research → Mechatronic systems → Inverted pendulum driven by pneumatics



The inverted pendulum is a classic control problem and is very popular mechatronic application. However, what distinguishes described mechanism from common practice is its drive. This cart-pole system is driven by pneumatics. Many disciplines that form part of mechatronics, and their composite subject can be taught with the projects like the pneumatically driven inverted pendulum. It requires good knowledge in modeling, simulation, control and hardware implementation, yet it is affordable and relatively simple. Influences of design parameters variation (although just mass or pendulum length can be changed) on the behaviour of the system can be observed and compensated for by different control parameters or methods. Different possible sensors, actuators, outputs, and their influences on the system can be considered on this laboratory model.

Below figures illustrate the photo of the experimental setup (see experimental system description) and the schematic diagram of the pneumatically actuated inverted pendulum.

  1. Linear potentiometer
  2. Rodless cylinder
  3. Inverted pendulum
  4. Rotational servopotentiometer
  5. Electronic rerference card
  6. Pressure transducer
  7. Proportional valve
  8. Filter with pressure regulator
  9. Air supply valve
  10. Electronic interface
  11. PC computer

Photography of inverted pendulum

Schematic diagram of control system


The goal of this control problem is to hold the pole upright. The control algorithm is realized based on developed mathematical model of the inverted pendulum system and the state-variable feedback controller. The controller gain was obtained by using linear quadratic regulator (LQR) optimal design. Below figure illustrates the experimental results of the control system. The disturbances to the system were just impulses given to the pendulum by flicking it with fingertips. It can be seen that the pendulum was completely calmed after circa 5 seconds.

Experimental results of inverted pendulum using state feedback controller


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