In this paper the balance control/stabilization system design and implementation for a rotational inverted pendulum RIP was presented. Bringing up the pendulum from its stable position (named downward position) to the unstable position (upright position) is not the subject of this scientific work and thus has not been studied. So, it is considered that the pendulum is in the upright position (or very close to it) and balance control system aims to keep it stable there even in presence of disturbances. Knowing the particular nature of the RIP system consists in non- linearities, modeling uncertainties and instability a modern fuzzy-PD control system was designed, which has as inputs the pendulum angle error and change in the angle error.
The implementation of the RIP balance control problem must meet some several tasks and for this we proposed a low cost solution based on a hardware platform with three microcontrollers. The distribution of the tasks to the microcontrollers and using the I2C serial for data communication increase the computing speed. The monitoring process is made using a Labview application which receives the recorded data via RS232 serial bus. Although the serial communication with the computer is slower than the master-slave communication between the interfaces of the platform, it does not intervene in the control process and the PC is used for monitoring purposes only. Evolution of process signals reveals that the aim of this work was accomplished