Industrial Robotic Arm 215

　　To address the array of challenges associated with writing applications in machine language, developers first turned to mnemonic symbols as a substitute for hard-to-remember machine instructions. This symbolic notation for representing computer instructions is known as symbolic language, or assembly language. In assembly language, each symbolic instruction corresponds one-to-one with a machine instruction; this greatly reduces the cognitive load, making it easier to detect and correct programming errors, while also allowing the compiler to automatically allocate storage locations for instructions and data. Programs written in assembly language are called source programs. Since computers cannot directly interpret or execute source code, it must be translated into machine language—understandable and executable by the computer—using a specialized program known as an assembler. Even when programming in assembly language, developers must maintain a thorough understanding of the computer system’s hardware architecture, which makes assembly‑level programming inherently inefficient and cumbersome. Nevertheless, because assembly language is tightly coupled with the underlying hardware, it remains a highly effective tool in specific contexts—such as core system routines that demand extreme time‑ and space‑efficiency, or real‑time control applications—where its low‑level capabilities continue to provide indispensable value.
　　
　　Currently, there is no unified classification standard for industrial robotic arms. They can be categorized in various ways depending on specific requirements.
　　
　　I. Classification by Drive Type
　　
　　1. Hydraulic Type: Hydraulic‑driven robotic arms typically comprise a drive system consisting of hydraulic actuators (various types of cylinders and hydraulic motors), servo valves, oil pumps, and an oil tank, with the arm’s end‑effector performing the task. They generally offer substantial lifting capacity—often exceeding several hundred kilograms—and are characterized by a compact structure, smooth motion, resistance to impact and vibration, and excellent explosion‑proof performance. However, their hydraulic components demand high manufacturing precision and superior sealing; otherwise, oil leakage can contaminate the environment.
　　
　　2. Pneumatic Type: Its drive system typically consists of pneumatic cylinders, air valves, air tanks, and an air compressor. It is characterized by readily available air supply, rapid actuation, simple structure, low cost, and ease of maintenance. However, it is difficult to achieve precise speed control, and the operating pressure cannot be too high, resulting in relatively limited gripping force.
　　
　　3. Electric Actuation Electric actuation is currently the most widely used drive method in robotic manipulators. It features convenient power supply, fast response, and substantial driving force (with joint-type models capable of handling payloads up to 400 kg). Signal sensing, transmission, and processing are straightforward, and a variety of flexible control strategies can be implemented. Drive motors typically include stepper motors, DC servo motors, and AC servo motors, with AC servos being the predominant choice today. Given the high rotational speeds of these motors, speed-reducing mechanisms—such as harmonic drives, RV cycloidal gear reducers, gear drives, worm drives, and multi‑link mechanisms—are commonly employed. Recently, some robotic arms have begun adopting direct‑drive (DD) configurations that utilize high‑torque, low‑speed motors without intermediate reducers. This approach not only simplifies the mechanical architecture but also enhances control accuracy.
　　
　　II. Classification by Purpose
　　
　　1. Handling robotic arms: These arms are highly versatile and typically require only point‑to‑point control. In other words, the parts being handled do not need a precisely defined motion trajectory; the only requirement is accurate positioning at the start and end points. Examples include loading/unloading robots used on machine tools, workpiece‑stacking arms, and auxiliary equipment for injection molding machines.
　　
　　2. Spray‑painting robotic arm: This type of robotic arm is commonly used on paint‑spraying production lines, where high repeatability in pose accuracy is not required. However, because paint mist is flammable, it typically employs hydraulic actuation or AC servo motor drive.
　　
　　3. Welding Robotic Arms This is currently the most widely used type of robotic arm, which can be further divided into two categories: spot welding and arc welding. Spot-welding robotic arms typically handle heavy loads. Basic Introduction When people think of robots, many immediately picture humanoid machines with hands and feet. However, such robots are usually seen in science fiction movies, entertainment venues, exhibitions, and toy stores—quite different from industrial robots. Industrial robots, often abbreviated as IRs, are generally simple handling devices that are sometimes referred to as robotic arms. They perform straightforward tasks such as lifting or lowering objects, inserting or removing workpieces within machinery, and so on. Nevertheless, many industrial robots can be fully programmed to carry out a variety of operations, including searching, transporting, gripping, aligning, assembling, inspecting, and more. To provide a clear definition, the Robotics Industries Association of the United States defined in 1979 an industrial robot as a programmable, multifunctional manipulator capable of moving materials, workpieces, tools, or specialized equipment through programmed control and diverse motion patterns to accomplish a series of tasks. Thus, even if many industrial robots do not resemble humans, they can still be classified as robots as long as they meet this definition. Although industrial robots are already extensively employed across numerous manufacturing sectors, it is estimated that hundreds of thousands more will enter service in the near future. At present, many researchers are exploring ways to integrate vision and sensory capabilities into robots, enabling them to perform increasingly complex tasks. The scientific discipline dedicated to studying robots is known as robotics.
　　
　　4. Assembly robots: These robotic arms must achieve high positional and orientational accuracy, with a wrist that exhibits significant flexibility. Currently, they are predominantly used for assembly operations in electromechanical products.
　　
　　5. Special-purpose robotic arms, such as medical‑care robots, space‑exploration robots, marine‑surveying robots, and hazard‑removal robots, among others.
　　
　　III. Classification Based on the Position, Mechanism Type, and Number of Degrees of Freedom of the Manipulator
　　
　　The configuration of the manipulator’s position mechanism is a key structural characteristic of the robotic arm. According to this classification, robotic arms can be categorized into Cartesian‑coordinate type, cylindrical‑coordinate type, spherical (polar)‑coordinate type, and articulated (or anthropomorphic) robotic arms.
　　
　　The number of axes (degrees of freedom) of the manipulator itself best reflects the arm’s operational capabilities and serves as a key criterion for classification. According to this classification scheme, robotic arms can be categorized into 4-axis, 5-axis, 6-axis, 7-axis, and other types.
　　
　　There are also various other classification methods.
　　
　　Basic Introduction to Industrial Design
　　
　　Industrial robots typically consist of six basic components: the structure, the end-effector, the digital controller, the actuators, the feedback system, and the sensors.