Industrial robots and cobots are robot arms that pick, place, assemble, glue and inspect parts in a factory. An ordinary industrial robot is strong and fast, and works inside a safety cage, where no person can enter while it moves. A cobot, short for collaborative robot, is built to work beside people, often with no cage.
The difference is in safety. A cobot is slower and lighter. It has sensors in its joints, and it stops at once when it touches something unexpected, such as a person's arm. So, after a safety check of the task, the factory can place it at a bench where a worker also stands.
A typical robot arm has six joints, called axes, and a gripper at the end. A person teaches it a job in one of two ways. The person can move the arm by hand to each point, or can steer it with a handheld screen called a teach pendant, and the robot stores the points. It then repeats the same path thousands of times with the same accuracy. This is why a robot suits a job that is repeated unchanged, such as welding the same seam on every door, and why it is poor at a job where every part lies in a different place.
Say a small foundry in Howrah buys a cobot to load metal parts into a press. Before, a worker lifted each part and put it in, about 400 times a shift, and the work was tiring and risky. Now the cobot picks each part from a tray and puts it in the press, and the worker only refills the tray and checks the finished parts. The cobot does not need a cage, so it fits in the small shed.
A robot arm only moves; it cannot tell by itself when to start or where a part lies. It needs a PLC to tell it when to start, and cameras to tell it where the part is. A newer type of robot uses robotics foundation models, which are large AI models trained to control robots. With these, the robot can learn a new task from examples, as shown in AI robotic picking.
Robots are grouped by how much they decide on their own. See levels of autonomy. Robot arms are used in assembly automation, and in other fields, such as sterilisers, bioreactors, construction, surgery with an orthopaedic surgical robot, and in warehouses with goods-to-person robots and mobile robots.