Working on topics like AI can be done without any moveable parts, but to delve for SLAM/Navigation or Human Robot Interaction is more informative if the robot can move.
In this case we highly recommend the usage of ROBOTIS Dynamixel Servo motors, which are available with different technical details like: dimensions, torque, interface, supply voltage and price. But there are also many more capabilities like the usage of DC/Brushless motors, PWM Servos and so on. So share your project with us and start a discussion!