Industrial robots are divided into the following categories according to the coordinate form of the manipulator:
Cartesian industrial robot
Its moving part is composed of three mutually perpendicular linear movements (i.e. PPP), and its workspace graph is rectangular. Its moving distance in each axis can be read directly on each coordinate axis. It is intuitive, easy to program and calculate the position and posture, high positioning accuracy, uncoupled control, simple structure, but the body occupies large space, small range of action, poor flexibility, and difficult to coordinate with other industrial robots.
Cylindrical coordinate industrial robot
Its motion form is realized by a motion system composed of one rotation and two movements. Its working space graph is a cylinder. Compared with the rectangular coordinate industrial robot, under the same working space conditions, the body occupies a small volume and has a large range of motion. Its position accuracy is second only to the rectangular coordinate robot, and it is difficult to coordinate with other industrial robots.
Spherical coordinate industrial robot
Spherical coordinate industrial robot is also called polar coordinate industrial robot. Its arm motion is composed of two rotations and a linear motion (i.e. RRP, one rotation, one pitching and one telescopic motion). Its working space is a sphere. It can pitch up and down and grasp the coordinated workpiece on the ground or at a lower position. Its position accuracy is high, and the position error is proportional to the arm length.
Multi-joint industrial robot
It is also called rotary coordinate type industrial robot. The arm of this industrial robot is similar to the human integrated upper limb. Its first three joints are the rotary joint (RRR). The industrial robot is generally composed of a column and a big arm. The column and the big arm form shoulder joints, and the big arm and the small arm form elbow joints, which can make the big arm do rotary motion and pitch swing, and the small arm do pitch swing. It has the most compact structure, large flexibility, the smallest floor area, and can coordinate with other industrial robots, but its position accuracy is low, there is balance problem, and control coupling. This kind of industrial robot is more and more widely used.
5) Planar joint industrial robot
It uses one moving joint and two rotary joints (PRR) to realize up and down motion, while the two rotary joints control forward and backward, left and right motion. This type of industrial robot is also known as SCARA (Selective Compliance Assembly Robot Arm) assembly robot. In the horizontal direction, it has flexibility, while in the vertical direction, it has greater rigidity. It has simple structure and flexible action, and is mostly used in assembly operations. It is especially suitable for the plug-in assembly of small size parts, for example, it is widely used in the plug-in and assembly of electronic industry.