Robotics Vocabulary Quiz
12 multiple-choice questions on robotics vocabulary: actuators, sensors, end effectors, kinematics, degrees of freedom, payload and autonomous systems. B2–C1 level.
Robotics Vocabulary — FAQ
An actuator is a component that converts energy — usually electrical, hydraulic or pneumatic — into physical movement. It is what makes a robot's joints and parts actually move. If sensors are a robot's 'senses', actuators are its 'muscles'. Common examples include electric motors, servos and hydraulic cylinders that drive a robot arm or wheels.
A sensor gathers information about the environment or the robot itself — for example, detecting distance, light, temperature, force or position — and sends that data to the controller. An actuator does the opposite: it takes a signal from the controller and produces movement or action. In short, sensors are inputs (sensing) and actuators are outputs (acting), and a robot needs both to interact with the world.
An end effector is the device at the end of a robotic arm that interacts directly with the environment to perform a task. It is essentially the robot's 'hand'. Depending on the job, an end effector might be a gripper for picking things up, a welding torch, a paint sprayer, a suction cup or a screwdriver. The end effector is chosen to match the specific task the robot must carry out.
Kinematics is the study of motion without considering the forces that cause it — in robotics, it describes how a robot's joints and links move and where its end effector ends up in space. 'Forward kinematics' calculates the position of the end effector from the joint angles, while 'inverse kinematics' works backwards: it calculates the joint angles needed to place the end effector at a desired position.
Degrees of freedom (DOF) refers to the number of independent ways a robot or joint can move. Each joint that can move adds one degree of freedom. A robot arm with six degrees of freedom can reach any position and orientation within its workspace, which is why six-axis industrial robots are so common. More degrees of freedom generally mean greater flexibility but also greater complexity to control.
An autonomous robot is one that can operate and make decisions on its own, without continuous human control. It uses sensors, software and sometimes artificial intelligence to perceive its environment and choose its actions. This contrasts with a 'teleoperated' robot, which is controlled remotely by a human in real time, and a 'semi-autonomous' robot, which combines independent operation with occasional human input.
An articulated robot is one whose arm has several rotary joints, similar to a human arm with its shoulder, elbow and wrist. The word 'articulated' means having joints that allow bending and rotation. These are the most common type of industrial robot because their multiple joints give them a wide range of movement, letting them reach around obstacles and work in complex positions.
Payload is the maximum weight a robot can safely carry, lift or manipulate at its end effector, including any tools or grippers attached. It is a key specification when choosing a robot for a task: a robot designed to assemble small electronics has a low payload, while one that lifts car parts on a production line needs a high payload. Exceeding the rated payload can damage the robot or reduce its accuracy.
In robotics these terms are related but distinct. Accuracy is how close the robot gets to a target position it was commanded to reach. Repeatability is how consistently the robot returns to the same position each time it tries — a robot can be highly repeatable but not accurate. Precision describes the fineness of the robot's movements and measurements. Industrial robots are usually prized for high repeatability.
A cobot, short for 'collaborative robot', is a robot designed to work safely alongside humans in a shared workspace, without the safety cages that traditional industrial robots need. Cobots use sensors to detect people and slow down or stop to avoid injury. They are typically lighter, easier to program and intended to assist human workers with repetitive or strenuous tasks rather than replace them entirely.