Usually used as a technical indicator for robots, it reflects the flexibility of robot actions and can be represented by the number of linear movements, swings, or rotations of the axis. The number of joints that a robot mechanism can independently move is called the degree of freedom of the robot mechanism, abbreviated as Degree of Freedom, which is abbreviated as DOF. At present, the control method adopted by industrial robots is to treat each joint on the manipulator as a separate Servomechanism, that is, each axis corresponds to a server, each server is controlled by the bus, and the controller uniformly controls and coordinates the work.
IS08373 explains industrial robots as follows: "Robots have automatic control, reprogrammability, and multi-purpose functions. The robot operator has three or more programmable axes. In industrial automation applications, the robot's base can be fixed or movable. It can be seen that the number of axes of industrial robots is an important technical indicator.
The application of robots with different degrees of freedom in industry is determined by the number of robot axes. Is it better to have more degrees of freedom?
The more degrees of freedom, the closer it is to the action function of the human hand, and the better its versatility; However, the more degrees of freedom, the more complex the structure, and the higher the overall requirements for robots, which is a contradiction in robot design. As the number of axes increases, the flexibility of the robot also increases. However, in current industrial applications, the most commonly used are three axis, four axis, five axis dual arm, and six axis industrial robots, and the selection of the number of axes usually depends on the specific application. This is because in some applications, high flexibility is not required, while three-axis and four-axis robots have higher cost-effectiveness, and three-axis and four-axis robots also have significant advantages in speed. If it is only for some simple applications, such as picking and placing parts between conveyor belts, then a four axis robot is sufficient. If the robot needs to work in a narrow space and the robotic arm needs to twist and reverse, a six axis or seven axis robot is the best choice.
Currently, six axis robots are the most widely used in the industrial field. An industrial robot with six joints is very similar to a human arm, with parts equivalent to the shoulders, elbows, and wrists. Its "shoulders" are usually installed on a fixed base structure. The function of a human arm is to move the hand to different positions, while the function of a six axis robot is to move the end effector and install various actuators suitable for specific application scenarios at the end of the robotic arm, such as grippers, spray lamps, drill bits, and sprayers, to complete different work tasks.
Recently, various robot manufacturers have released the latest human-machine collaborative robots, almost all of which use seven axis redundant degree of freedom industrial robots. Internationally renowned robot manufacturers have made efforts to launch new products for seven axis robots to seize the high-end new market. However, compared with traditional four axis and six axis industrial robots, the gap in product types and sales proportion is currently very significant.