All motion is provided by three servo motors included with the Mindstorm NXT. Usually two motors are used together to provide mobility for the robot. The third servo provides power to some secondary function, such as a gripping hand or hook. The servo motors are connected to the brick using the modular wire provided by the Mindstorm NXT. The servo motors are shown in Figure 1.8.

Figure 1.8: Servo Motors

Many of the projects align the servo motors in a tricycle configuration. The two mobility servos are placed at the front to provide movement and turning. While the third servo is placed at the rear to provide some additional functionality to the robot being created. Additionally, a small unpowered wheel is generally provided towards the back for stability.

Figure 1.9 shows the tricycle configuration.

Figure 1.9: Typical Tricycle Configuration