What Are Robots?

Robots are programmable machines capable of carrying out a complex series of actions automatically, typically by sensing their environment, processing that sensory information, and executing physical motion through actuators. They are distinguished from simpler machines by their capacity for programmability, which allows a single robot platform to perform different tasks by changing its software rather than its hardware. The design and study of robots draws from mechanical engineering, electrical engineering, computer science, and cognitive science, integrating structural design, sensing, actuation, and control into systems that range from fixed industrial manipulators to fully autonomous mobile platforms.

The word "robot" was coined by Czech playwright Karel Capek in his 1920 play R.U.R., but the engineering concept developed through decades of work in cybernetics, servomechanisms, and numerical control. The first commercially deployed industrial robot, the Unimate arm installed at General Motors in 1961, established the template for the dominant form of robotics for the next several decades.

Industrial and Robotic Arms

Industrial robots are programmable manipulators used in manufacturing to perform tasks such as welding, painting, material handling, and precision assembly. They are typically fixed-base serial-link arm structures with five or six rotational degrees of freedom, operating at speeds and repeatability levels that human workers cannot match consistently. Repeatability figures of 0.02 mm or better are common for mid-range industrial arms. Robotic arms are the most widely deployed class of robot globally, with annual installations tracked by the International Federation of Robotics exceeding 500,000 units in recent years. The IFR World Robotics report provides the most comprehensive annual data on industrial robot deployment worldwide.

Autonomous and Mobile Robots

Autonomous robots are systems that perform their designated tasks without continuous human control, relying on onboard sensing, computation, and decision-making to adapt to their environment. Mobile robots extend this capability to platforms that translate or navigate through space, including wheeled ground vehicles, legged walkers, and aerial drones. Navigation depends on localization (estimating the robot's position relative to a map or reference frame), mapping (building or updating a representation of the environment), and path planning (selecting a collision-free route to a goal). The ROS (Robot Operating System) documentation maintained by Open Robotics provides the software framework most widely used to implement autonomous navigation stacks on research and commercial mobile robot platforms.

Humanoid and Service Robots

Humanoid robots are designed with a physical form that approximates the human body, typically including a torso, two arms with articulated hands, and legs for bipedal locomotion. The motivation is that environments designed for humans, including buildings, vehicles, and tools, can be used by humanoid robots with less modification than would be needed for non-anthropomorphic platforms. Bipedal walking control remains technically demanding, requiring real-time balance control that compensates for ground irregularities and external disturbances. Service robots are a broader category encompassing any robot that performs useful tasks outside industrial production, including domestic cleaning robots, surgical assist systems, hospital logistics robots, and guide robots for the visually impaired.

Agricultural, Medical, and Swarm Robots

Agricultural robots perform crop monitoring, targeted pesticide application, fruit picking, and soil sampling in environments that are semi-structured but highly variable due to weather, plant growth, and terrain. Medical robots support surgical procedures, rehabilitation, drug dispensing, and patient handling, with the da Vinci Surgical System representing the most commercially widespread example of robot-assisted surgery. Swarm robots are large collections of relatively simple individual robots that coordinate using local communication rules to accomplish tasks collectively, drawing inspiration from social insects. Swarm approaches offer scalability and fault tolerance because the collective behavior does not depend on any single robot. Research on swarm systems is published extensively in IEEE Transactions on Robotics and related venues.

Applications

Robots have applications in a wide range of fields, including:

• Manufacturing, for assembly, welding, painting, and quality inspection
• Healthcare, including minimally invasive surgery and patient rehabilitation
• Agriculture, for automated harvesting, planting, and crop monitoring
• Space exploration, including planetary rovers and satellite-servicing manipulators
• Logistics and e-commerce fulfillment in automated warehouses
• Search and rescue operations in disaster environments hazardous to humans