Machines that are carrying out actions automatically are classified as industrial robots and service robots. Service robots include collaborative robots work with people (Cobots) are still a small market (2-3%).
The ubiquitous industrial robot is used to increase efficiency, productivity and profitability. By 2025, over 4 million robots along with automation and control systems will be installed in 50,000 warehouses.
A good source of information on robotics is the industry association of robot manufacturers and national robot associations The International Federation of Robotics (IFR).

The National Institute of Standards and Technology (NIST) describes the 4 main types of  industrial robots
https://www.nist.gov/blogs/manufacturing-innovation-blog/4-types-robots-every-manufacturer-should-know
articulated robot – the normal arm type robot what
An articulated robot is the type of robot that comes to mind when most people think about robots. Much like CNC mills, articulated robots are classified by the number of points of rotation or axes they have. The most common is the 6-axis articulated robot. There are also 4- and 7-axis units on the market.

Kawasaki Robotics GmbHKawasaki painting robot
https://robotics.kawasaki.com/en1/index.html?language_id=4

A Selective Compliance Articulated Robot Arm (SCARA) is a good — and cost-effective — choice for performing operations between two parallel planes (e.g., transferring parts from a tray to a conveyor). SCARA robots excel at vertical assembly tasks such as inserting pins without binding due to their vertical rigidity.

Delta robots, also referred to as “spider robots,” use three base-mounted motors to actuate control arms that position the wrist. Basic delta robots are 3-axis units but 4- and 6-axis models are also available.

Cartesian robots typically consist of three or more linear actuators assembled to fit a particular application. Positioned above a workspace, cartesian robots can be elevated to maximize floor space and accommodate a wide range of workpiece sizes. (When placed on an elevated structure suspended over two parallel rails, cartesian robots are referred to as “gantry robots.”)

• General-purpose autonomous robots. Perform tasks and navigate spaces independently. The may be humanoid, speak.
• Factory robots
• Dirty, dangerous, dull or inaccessible tasks
• Military robots
• Mining robots
• Healthcare
• Research robots
• Contemporary art and sculpture

Sensors are used by robots to:

• Monitor internal systems such as arm position and state of charge
• Monitor their local operating environment for their own operational purposes such as location in a factory and proximity to people.
• Determine information about the environment and the things that they are interacting with.

• Acceleration and vibration
• Charging/Power
• Force and torque
• Light - Vision
• Location - Navigation and Positioning
• Position and angle
• Pressure
• Proximity
• Sound
• Tactile
• Temperature