Overview and classification of servo motors
Servo motors, also known as actuator motors, are used as actuators in automatic control systems. They convert received electrical signals into angular displacement or angular velocity outputs on the motor shaft. Servo motors are divided into two main categories: DC servo motors and AC servo motors. AC servo motors are further divided into asynchronous servo motors and synchronous servo motors.
In both servo and speed control applications, AC systems are gradually replacing DC systems. Compared to DC systems, AC servo motors offer advantages such as high reliability, better heat dissipation, lower moment of inertia, and the ability to operate under high voltage. Because they lack brushes and steering gears, AC servo systems are also known as brushless servo systems, using brushless squirrel-cage induction motors and permanent magnet synchronous motors.
DC servo motors are divided into brushed and brushless motors.
Brushed motors are low in cost, simple in structure, have high starting torque, wide speed range, and are easy to control. They require maintenance, but maintenance is convenient (replacing carbon brushes). They generate electromagnetic interference and have requirements for the operating environment. They are usually used in cost-sensitive general industrial and civilian applications.
Brushless motors are small in size and light in weight, with high output, fast response, high speed and low inertia, stable torque and smooth rotation. They are complex and intelligent in control, with flexible electronic commutation methods that can use square wave or sine wave commutation. The motors are maintenance-free, highly efficient and energy-saving, with low electromagnetic radiation, low temperature rise and long life, and are suitable for various environments.
Features of different types of servo motors
Advantages and disadvantages of DC servo motors : Advantages: precise speed control, strong torque-speed characteristics, simple control principle, easy to use, and inexpensive.
Disadvantages: Brush commutation, speed limitation, additional resistance, generation of abrasive particles (not suitable for dust-free or explosive environments).
Advantages and disadvantages of AC servo motors: Advantages: Excellent speed control characteristics, smooth control across the entire speed range with almost no oscillation, high efficiency (over 90%), low heat generation, high-speed control, high-precision position control (depending on encoder accuracy), constant torque within the rated operating range, low inertia, low noise, no brush wear, and maintenance-free (suitable for clean and explosive environments). Disadvantages: More complex control, driver parameters require on-site adjustment of PID parameters, and more wiring is required.
Servo motor industry chain structure
The control systems and automation products for industrial robots mainly involve servo motors, reducers, controllers, and sensors. Servo motors are the power system of industrial robots, generally installed at the robot's "joints," and are the "heart" of the robot's movement.
Currently, robot joint actuation relies heavily on servo systems. The more joints a robot has, the higher its flexibility and precision, and the more servo motors are required. Robots place high demands on servo systems, requiring them to meet requirements such as fast response, high starting torque, large torque-to-inertia ratio, wide speed range, and adaptability to the robot's shape to achieve small size, light weight, and acceleration/deceleration capabilities, while also demanding high reliability and stability. Currently, AC servo systems are widely used in industrial robots.
Market size of servo motors
The servo motor market is highly competitive, with foreign companies currently holding a dominant position. Servo motors are used as actuators in robots and are a major factor affecting robot performance. AC servo motors are the most widely used in the robotics industry, accounting for approximately 65% of servo motors.
Foreign companies dominate the servo system market. Currently, the mainstream suppliers in the Chinese industrial machinery market include Panasonic, Yaskawa, and Mitsubishi from Japan, as well as Lenz and Bosch Rexroth from Europe and the United States. Japanese brands have monopolized the small and medium-sized OEM (Original Equipment Manufacturer) market with their superior product performance and highly competitive prices. In recent years, among the top 15 servo system manufacturers, the top three are all Japanese brands, accounting for 45% of the total market share. European brands such as Siemens, Bosch, and Schneider Electric occupy the high-end market, with an overall market share of around 30%. Domestic companies hold an overall market share of less than 10%.
Currently, my country has achieved large-scale mass production of low- and mid-range servo systems, but high-end servo systems have not yet achieved commercialization and mass production capabilities. Domestic demand for precision servo motor control systems mainly relies on imports. With the booming development of the robotics industry, supported by favorable policies, and the continuous improvement of domestic servo technology, the pace of import substitution for servo systems in my country will accelerate.
Analysis of China's Servo Motor Production
Controllers and servo systems are closely intertwined, and users prioritize reliability and stability, price, and service. Improving service and cost-effectiveness is a key area for domestic companies to focus on. However, this requires long-term, in-depth research in motion control, substantial financial investment, and extensive market validation. It demands high levels of technology, capital, and talent. Domestic listed companies such as Siasun, Siasun Technology, Inovance Technology, Guangzhou CNC, and Estun Automation possess similar capabilities.
A well-known servo motor company
Lenz
Lenze AG is one of Germany's leading industrial innovation companies, employing approximately 3,200 people worldwide. Around 300 of its employees in Germany are engaged in research and development. The company primarily focuses on products, solutions, systems, and services for mechanical and electronic drives. Headquartered in Hamelin, Germany, the company was founded in 1947 by Hans Lenze.
Lenze's product range includes frequency converters, servo drives, gearboxes, motors, brakes, and clutches. Furthermore, it offers automation solutions that integrate software, visualization, and control, as well as systems engineering, coupling technologies, and services.
Lenz MCS synchronous servo motor
Lenze MCS synchronous servo motors are used for precisely controllable motion, with a torque range from 0.5 to 190 Nm (0.25 to 15.8 kW), and are particularly suitable for applications requiring high dynamics, high precision, and minimal size. They feature high overload capacity, high rotational acceleration, and utilize plug-in technology for quick installation and ease of use. An electronic nameplate facilitates easy adjustment.
Kollmorgen
Kollmorgen is a large, stable, and locally supported multinational company with over 2,000 employees in 20 offices worldwide. It is backed by Fortive (NYSE: FTV.WI), a globally recognized brand that is a leader in field instrumentation, transportation, testing, product implementation, automation and specialization, and franchise distribution.
Kollmorgen's motors, drives, and controllers have been used in Mars and space exploration, ships and submarines, oil and gas drilling and metering, surgical robots and laser eye surgery, and even artificial hearts.
Kollmorgen AKM series servo motors
AKM servo motors boast industry-leading performance and power density, with low tooth jamming and low harmonics ensuring smooth operation. They are easy to use, plug-and-play, and automatically tune with AKD drivers. A wide range of standard products are available, and joint R&D customization is also possible.
Mitsubishi
Mitsubishi Electric is one of the world's leading brands in the manufacture and sale of electrical and electronic products and systems, which are widely used in numerous fields and applications. As a leading global green company, Mitsubishi uses its technology to contribute to society and people's daily lives worldwide.
Mitsubishi Electric HG-KR Servo Motor
Mitsubishi Electric's MELSERVO-J4 series servo motors utilize a dedicated execution engine with a unique high-speed servo control structure and a maximum response frequency of 2.5kHz. Combined with its independently developed high-resolution absolute position encoder (4,194,304p/rev), processing speed is significantly improved. The MELSERVO-J4 rotary servo motors include three series: HG-KR (small capacity, low inertia), HG-MR (small capacity, ultra-low inertia), and HG-SR (medium capacity, medium inertia).
Bosch Rexroth
Bosch Rexroth is a leading global expert in drive and control technologies, providing safe, precise, efficient, and cost-effective drive and control technologies for all types of machinery and systems. The company integrates global application experience to develop innovative products, tailoring system solutions and services to customers in every segment of the mobile machinery, mechanical applications and engineering, factory automation , and renewable energy markets. Bosch Rexroth also provides customers with a wide range of hydraulic, electronic drive and control, pneumatic, gear, linear drive, and assembly technologies. The company operates in more than 80 countries worldwide, employs over 37,500 professionals, and achieved global sales of nearly €6.5 billion in 2012.
Bosch Rexroth MSK synchronous servo motors
The MSK series motors are characterized by their wide power range and fine size classification. These synchronous servo motors feature high torque density, with a maximum torque of up to 495 Nm (self-cooled). Two encoder models are available to suit different levels of accuracy. Furthermore, various optional accessories such as keyways and brakes, increased concentricity, and IP65 protection ratings are available, allowing the system to be used with fans, water cooling systems, and ATEX.
Yaskawa
Yaskawa Electric is a world-class manufacturer of drive products. Yaskawa Electric (China) Co., Ltd., with nearly 100 years of history, is a wholly foreign-owned enterprise invested by Yaskawa Electric Corporation of Japan. It was registered in Shanghai in April 1999 with a registered capital of US$31.1 million. Its business scope includes Yaskawa-branded inverters, servo motors, controllers, robots, various system engineering equipment, accessories, and other mechatronics products.
Yaskawa Electric is a professional manufacturer in the field of motion control. It was the first company in Japan to produce servo motors, and its products are renowned for their stability, speed, and high cost-performance ratio. It is the world's largest-selling servo brand with the widest range of applications. From general industrial machinery to semiconductor and electronic component manufacturing equipment, Yaskawa provides the most suitable servo and controller products for various applications.
Yaskawa ∑-V series servo motors
Yaskawa's ∑-V series (rotary) servo motors feature reliable wiring, oil and dust resistance, and high amplifier responsiveness, significantly reducing settling time to 1/12 of previous Yaskawa products. Improved vibration suppression enhances tracking performance and shortens settling time. Furthermore, it reduces vibration (noise) during drive and at the mechanical front end when stopped, improving mechanical performance through the combination of medium-inertia motors.
Siemens
Siemens is one of the world's largest electrical and electronics companies, maintaining its success for over 150 years. In 2003, its revenue ranked 21st on the Fortune 500 list, and it topped the list among electrical and electronics companies. Siemens is a large international company whose business is primarily focused on six areas: information and communication, automation and control, power, transportation, medical systems, and lighting.
Siemens' industrial business area offers unique automation technologies, industrial control and drive technologies, and industrial software to meet all the needs of manufacturing companies, covering the entire value chain—from product design and development to product manufacturing, sales, and service.
Siemens 1FT7 servo motor
The 1FT7 motor is a compact synchronous motor suitable for high-performance applications, meeting stringent requirements for accuracy, dynamic characteristics, speed set range, protection rating, and robustness. It features the latest encoder technology and is optimized for use with Siemens' fully digital drive and control systems. Cooling options include natural cooling, external cooling, or water cooling.
Development Trends in the Servo Motor Industry
Digitalization: The replacement of analog control circuits with digital control technology in servo systems is an inevitable trend;
Intelligentization: Intelligentization mainly refers to the intelligentization of servo drives;
Simplification: Simplification is not about making things simple, but about streamlining. It involves enhancing the servo functions that users need, making them specialized and refined, while streamlining some unused functions. This reduces the cost of the servo system and creates more benefits for customers. We try to start from the actual needs of customers and form simple modular programming operations, making it easy and quick for users to use.
Networking: This refers to building network-based or bus-based private server systems. Fieldbus is a digital communication technology used in production environments to enable bidirectional, serial, and multi-node communication between field devices and between field devices and control devices. Building bus-based servos is one of the necessary ways to realize the Industrial Internet of Things (IIoT).
Increased efficiency: The servo system will use a more precise encoder to improve the system's sampling accuracy, while also improving the performance of the servo driver and continuously optimizing the inverter drive circuit to provide faster data processing speed and acceleration/deceleration performance of the servo system.
