The basic Structure and functionality of robots
Robotics is a very complex system that is based on their generation (first, second, and third-generation), or on the difference between autonomous and non-autonomous robots, it is not enough.
It is necessary to understand the structure of the robots and what their primary functions are to understand what typology and models of robots exist today. Basically, they have four "functional units," they must be seen as complex systems that have different "functional organs" (mechanical organs, sensory organs, control organs, governing, and calculation organs).
Before seeing each of these organs, it is worth remembering the definition of robotics provided by the Robotic Institute of America (RIA). "A robot is a multifunctional and reprogrammable manipulator for performing a variety of tasks. A robot also acquires information from the environment and moves intelligently accordingly. "
Looking at the definition of robotics provided by the Robotic Institute of America, the mechanical structure of a robot represents the "multi-function manipulator." In reality, this is mostly true for industrial robotics because if you look at service robotics, the mechanical structure corresponds to the robot's movement and locomotion system.
The mechanical organs are distinguished between apparatuses to perform operations and activities in a fixed place or devices able to move. If we wanted to make a parallelism with the organs of the movement of human beings, we would divide the mechanical organs into upper limbs and effectors. These are the tools like pine and robotic hands for manipulation and lower arms (not necessarily "mechanical legs," today the prerogative of the most sophisticated robots, but mechanical organs such as wheels, wheels, sleds, or kinematics systems).
The robotic systems are endowed with a sensory capacity that allows them to "perceive" the context in which they operate. It is not a question of human sensations, of course, but of a sensory structure that allows the robot to acquire data, both on the internal state of the mechanical structure. For example, position and speed), and on the surrounding external environment (exteroceptive sensors that make one perceives, for example, strength and proximity and give the robot an artificial vision).
Control structure (robot control organs)
The control organs act as connectors between perception and action and are the systems that guarantee the robot to perform the activities for which it is developed.
The control structure is given by actuators (electric motors, hydraulic or pneumatic systems, etc.) and control algorithms for driving the actuators.
Governance structure (memorization and calculation organs)
In this case, we refer to the systems that allow programming, calculate, check the activities, and the work done by the robotic machines. The governance and calculation structure is usually made up of hardware systems (microprocessors, memories, etc.) and software systems (application programs, calculation algorithms coded in programming languages, standard or dedicated).
Software architecture and programming
The governance unit must manage the operations that the robot system must perform based on an internal model of the automaton (its mechanical structure) and the data provided by the sensors. The contr architecture should be divided into hierarchical levels with the algorithms that determine the signals of the actuators and on the top step of the hierarchical scale. In a hierarchical structure of this type, each level sends the result of its computation to the underlying level, from which it is, however, retroactively influenced.
There are three main approaches to Looking at the programming of a robotic system:
- Teaching-by-showing: the robot is guided along a path and learns the positions reached thanks to the sensors; later, it merely replicates that sequence of positions.
- Robot-oriented: there is a high-level programming language with complex data structures, variables, routines.
- Object-oriented: as in the previous one, only that the language is object-oriented.
Among the computing organs today, there are also algorithms and artificial intelligence techniques that contribute to raising the level of independence of autonomous robots (for example, through machine learning).
Robot movement: kinematic analysis and dynamic analysis
As we have seen, a robot is a complex system that has an articulated mechanical structure. So that its functioning is adequate for the activities that its "behavior" (movement, functioning) must accomplish. It must be schematized in a mathematical model that takes into account the cause-effect bonds between the various constituent organs (mechanical organs, sensory organs, control organs).
These mathematical models can concern the kinematic analysis and the dynamic analysis of the motion of the robot.
- Kinematic analysis: it is the quantitative description of the motion of a robot (regardless of the causes of the motion itself). However, a distinction must be made between kinematics and differential kinematics. The first deals with the links between the internal parameters of the robot and their position and orientation that affect movement; the second defines speed-dependent relationships (to describe the motion of the robot in more detail).
- Dynamic analysis: It is the study of the motion of the automaton starting from its causes; that is the circumstances that determine and modify it. As we have seen, the actuators (control organs) that guarantee the robotic system the power necessary to perform a task or an activity have an impact on motion. But in this case, we must distinguish between dynamics and reverse dynamics. The first is for the calculation of the accelerations of the components of a robot as a function of the actuation forces. The inverse dynamics search for methods to determine the actuation forces that allow reaching the desired accelerations.
The various types of robots
As mentioned above, robots are machines and capable of performing a job in a more or less autonomous way instead of a man and are increasingly complex systems (often called humanoids or androids).
To investigate the peculiarities of autonomous and non-autonomous robots and understand its various generations, we need to know the types of robots. Here, we explore the various types of robots, highlighting the differences between anthropomorphs, humanoids, and androids.
The anthropomorphic are robotic systems that are able to emulate some human abilities such as the movement of arms and legs, perception, and movement in physical environments. This category of robots includes both humanoids and anthropomorphs intended as industrial robotics systems (typically the so-called robotic arms used in the industrial sector along the production lines).
The humanoids are autonomous robots with human features (resemble humans because they have a body with head, arms, and legs or wheels that recall the physicality of people, even if they are clearly recognizable as robots). Research is developing increasingly sophisticated humanoid robots with advanced technologies that give these machines cognitive and sensory capabilities.
The androids are always humanoid robots (in fact, they are very often used as synonyms) even if there is a tendency to make the robotic systems that not only resemble human beings but also replicate their features seeming to all intents and purposes of people.