Tap on the buttons to see BigDog’s sensing, computing, and actuation systems.Īs BigDog takes a step, it’s continually (several thousand times per second) updating its sensor, computer, and actuator information in a feedback loop that allows the robot to autonomously walk, trot, climb hills, and step over obstacles. Based on that information, BigDog’s computer calculates which hydraulic actuators it should activate to move the robotic legs. It also uses gyroscopes and an inertial measurement unit (IMU) to keep track of its position in relation to the ground. BigDog uses sensors to measure the position of its leg joints and the forces applied on them. To make things more concrete, consider BigDog, a rough-terrain quadruped robot developed by U.S. A robot is constantly repeating this sensing-computing-acting cycle, in what roboticists call a “feedback loop.” If you want to take away one thing from this tutorial, it’s this: Feedback makes machines smart, and almost every robot uses feedback. Some are designed to perform specific tasks, while others are more flexible and can do many different things.īut although robots vary in how they sense, compute, and act, they all operate in a similar way: Their sensors feed measurements to a controller or computer, which processes them and then sends control signals to motors and actuators. Some robots can move around and manipulate things. As for the action, this is where robots vary the most: Some robots can move around others can manipulate things.

Likewise, the compute part can involve everything from a small electronic circuit to a powerful multicore processor or even a cluster of networked computers. To sense the world, some robots use simple devices, like an obstacle-detecting sonar, while other robots rely on multiple sensors, including cameras, gyroscopes, and laser range finders. These three components vary widely from robot to robot. The thing to keep in mind about this or any other definition is that robots can typically do three things: sense, compute, and act. For Gill Pratt, another roboticist, that’s enough to call a thermostat a simple robot. A home thermostat can measure the ambient temperature, check a prestored schedule, and turn on the heating or cooling system accordingly. Is cruise control a robot?įor his part, Brooks is not enthusiastic about considering dishwashers a class of robot. It senses how fast the vehicle is going, compares it to a preset speed, and accelerates or brakes as needed.

Take, for example, cruise control in cars. You may argue, and perhaps rightly so, that the definition above could very well describe a dishwasher, a thermostat, an elevator, an automatic door, and many other systems and appliances around us. It uses sensors to autonomously drive around a room, going around furniture and avoiding stairs it carries out computations to make sure it covers the entire room and when deciding if a spot needs a more thorough cleaning and it performs an action by “sucking dirt,” as roboticist Rodney Brooks, one of the Roomba creators, explains.īut no definition is perfect.

So what makes a robot? Here’s a definition that is neither too general nor too specific:Ī robot is an autonomous machine capable of sensing its environment, carrying out computations to make decisions, and performing actions in the real world. And for most of us, science fiction has strongly influenced what we expect a robot to look like and be able to do. Even roboticists themselves have different notions about what is or isn’t a robot.

In fact, the term “robot” means different things to different people.

Brave robot train