Industrial robots are widely used in industrial manufacturing, such as automobile manufacturing, electrical appliances, and food processing. They can replace repetitive, mechanical manipulation work and are machines that achieve various functions through their own power and control capabilities. They can be directed by humans or operate according to pre-programmed procedures.
If you have some questions about the industrial robot industry, reading the following content can help you quickly build a basic understanding of industrial robots.
1. What is an industrial robot?
A robot is a machine with many degrees of freedom in three-dimensional space, capable of performing numerous human-like actions and functions. An industrial robot, on the other hand, is a robot used in industrial production. Its characteristics include: programmability, human-like design, versatility, and mechatronics integration.
2. What are the system components of an industrial robot? What is the function of each component?
(1) Main body
The main mechanical components, namely the base and actuator, include the upper arm, forearm, wrist, and hand, forming a multi-degree-of-freedom mechanical system. Some robots also have a locomotion mechanism. Industrial robots typically have six or more degrees of freedom, while the wrist usually has one to three degrees of freedom.
(2) Drive system
The drive system is the transmission mechanism that enables a robot to operate. Based on the power source, it is divided into three main categories: hydraulic, pneumatic, and electric. Depending on the requirements, these three types can also be combined into a composite drive system. Alternatively, it can be indirectly driven through mechanical transmission mechanisms such as synchronous belts, pulley systems, and gears. A drive system consists of a power unit and a transmission mechanism, used to execute the corresponding actions of the mechanism. Each of these three basic drive systems has its own characteristics; currently, the mainstream is the electric drive system.
(3) Control System
The robot's actuators are controlled by the robot's operating instructions and signals fed back from the sensors to complete the prescribed movements and functions.
High-performance, cost-effective microprocessors have brought new development opportunities to robot controllers, making it possible to develop low-cost, high-performance robot controllers. To ensure sufficient computing and storage capabilities, robot controllers now mostly adopt powerful chips such as ARM series, DSP series, POWERPC series, and Intel series.
(4) Sensing System
It consists of an internal sensor module and an external sensor module to acquire information about the internal and external environmental conditions.
Internal sensors: These are sensors used to detect the robot's own state (such as the angle between its arms), and are mostly sensors that detect position and angle. Specifically, they include: position sensors, angle sensors, etc.
External sensors: Sensors used to detect the robot's environment (e.g., detecting objects and their distance) and condition (e.g., detecting whether a grasped object has slipped). These include distance sensors, vision sensors, and force sensors.
The use of intelligent sensing systems has improved the mobility, practicality, and intelligence of robots. While human perception systems are more dexterous than robots in understanding information from the external world, sensors are more effective than human systems for certain specific information.
(5) End effector
An end effector is a component attached to the last joint of a robotic arm. It is typically used to grasp objects, connect with other mechanisms, and perform the required tasks.
3. What are the main parameters involved in industrial robots?
The main technical parameters of a robot include degrees of freedom, resolution, workspace, working speed, and working load.
The degrees of freedom of a robot refer to the number of independent motion parameters required to determine the position and orientation of the robot's hand in space. The number of degrees of freedom of a robot is generally equal to the number of its joints.
The working range refers to the entire spatial range that the mounting points of an industrial robot's arm or hand can reach. Its shape depends on the robot's degrees of freedom and the type and configuration of its joints. The working range of a robot is generally represented using two methods: graphical and analytical.
Speed: The distance or angle that the center of the mechanical interface or the center of the tool moves per unit time when the robot is under load and moving at a constant speed during operation.
Workload refers to the maximum weight that a robot wrist can withstand at any position within its working range when a load is mounted on its forearm. It is generally expressed as mass, torque, or moment of inertia.
It is also related to parameters such as running speed and acceleration. The workload is generally measured by the weight of the workpiece that the robot can grasp when running at high speed, which is used as an indicator of the load-bearing capacity.
Resolution refers to the minimum distance a robot can move or the minimum angle it can rotate.
Repeatability or repeatability accuracy refers to the variation in how often a robot repeatedly reaches a target position. Repeatability accuracy measures the concentration of a series of error values, i.e., repeatability. Robot accuracy depends not only on the joint reducers and transmission devices, but also greatly on the mechanical assembly process; many instances of decreased repeatability accuracy are due to improper assembly.
4. What are the performance differences between servo motors and stepper motors?
A servo drive, also known as a servo controller or servo amplifier, is a controller used to control servo motors. Its function is similar to that of a frequency converter for a regular AC motor, and it is part of a servo system. Generally, it controls the servo motor through three methods: position, speed, and torque, achieving high-precision positioning of the transmission system.
The control precision differs (the control precision of a servo motor is guaranteed by a rotary encoder at the rear end of the motor shaft, and the control precision of a servo motor is higher than that of a stepper motor);
The low-frequency characteristics differ (servo motors operate very smoothly and do not vibrate even at low speeds; generally, servo motors have better low-frequency performance than stepper motors).
The overload capacity differs (stepper motors do not have overload capacity, while servo motors have strong overload capacity);
The operating performance differs (stepper motors use open-loop control, while AC servo drive systems use closed-loop control);
The speed response performance differs (AC servo systems have better acceleration performance).
5. Basic Working Principle
The working principle is teach-and-playback; teaching, also known as guided teaching, involves manually guiding the robot step-by-step through the required action sequence. During the guidance process, the robot automatically memorizes the posture, position, process parameters, and motion parameters of each taught action and automatically generates a continuously executable program. After teaching is complete, only a start command needs to be given to the robot, and it will automatically complete the entire process according to the taught actions.
6. Applications of industrial robots in the processing and manufacturing field
AGV (Automated Guided Vehicle) handling robots enable unmanned operations in warehouses and storage areas, automating the handling of goods, semi-finished products, and raw materials during the production process, and can meet the application requirements of different environments.
Stamping robots are widely used in machinery manufacturing, metallurgy, electronics, light industry, and nuclear energy enterprises, mainly because these industries have a relatively large number of repetitive actions in the production process, making the application of stamping robots highly valuable. The robotic arm automatically removes the finished products and places them on a conveyor belt or receiving platform for transport to a designated target location. This allows one person to simultaneously monitor two or more injection molding machines, saving manpower and resources and reducing costs for enterprises in the production process.
Palletizing robots are automated devices that neatly and automatically stack packaged goods. Their end effectors are equipped with mechanical interfaces that allow for interchangeable grippers. Palletizing robots are used in industrial production and automated warehouses to improve productivity, reduce worker workload, and, in some harsh working environments, effectively protect worker safety.
High-speed robotic sorting can accurately track the speed of the conveyor belt in fast assembly line operations, and use visual intelligence to identify the position, color, shape, size, etc. of objects, and perform tasks such as packing, sorting, and arranging according to specific requirements.
Laser cutting utilizes the flexible and rapid working performance of industrial robots. Depending on the size of the workpiece to be cut, the robot can be mounted upright or upside down. Different products can be taught or programmed offline. The sixth axis of the robot is equipped with a fiber laser cutting head to perform three-dimensional cutting on irregular workpieces.
Using robots for welding operations can greatly improve production efficiency and economic efficiency. Welding parameters play a decisive role in the welding result; in manual welding, speed, weld extension, and other parameters are all variable. Robots can move at high speeds, reaching 3 m/s or even faster. Welding using robots can increase efficiency by 2 to 4 times compared to manual welding, and the welding quality is excellent and stable.
Employing industrial robot vision technology can avoid the impact of some external factors on inspection accuracy, effectively overcome the effects of temperature and speed, and improve inspection precision. Machine vision can detect the shape, color, size, brightness, length, etc. of products, and when combined with industrial robots, it can fulfill requirements such as material positioning, tracking, sorting, and assembly.
