The picture above is an AARM Motion control system. AARM stands for Advanced Architecture Robot and Machine Motion and it's a commercial product from American Robot for industrial machine motion control. The non-servo robot motion is started by the controller and stopped by a mechanical stop switch. The stop switch sends a signal back to the controller which starts the next motion. A continous path servo is appropriate when a robot must proceed on a specified path in a smooth, constant motion.
More sophisticated robots have more sophisticated control systems.
The brain of the Mars Sojourner rover was made of two electronics boards that were interconnected to each other with Flex cables. The control boards for Sojourner are shown below. Mobile robots can operate by remote control or autonomously. A remote control robot receives instructions from a human operator. In a direct remote control situation, the robot relays information to the operator about the remote environment and the operator then sends the robot instructions based on the information received.