Design and evaluation of two-wheeled balancing robot chassis: Case study for Lego bricks

Two-wheeled balancing robot is one of interesting nonlinear plant. The goal is to control the robot so that it can move with only two wheels. This paper elaborates the design and evaluation of its chassis. The chassis is constructed with Lego Mindstorm NXT and controlled by the AVR ATMega16 microcontroller. The system uses MX2125 accelerometer sensor from Parallax to evaluate the robot chassis. Two chassis design, i.e. model A and B are developed. From the experiments, it is shown that robot chassis design must address the mechanically stable issue. Therefore chassis model A is discarded. PD controller is recommended for this chassis model B. The chassis also considers the flexibility to mount such a load. Mounting load under the axis helps to stabilize the chassis. This makes the controller design easier. The load position opens the further research topic. Using Lego Mindstorm is very helpful in design and evaluation of mechatronics set up.