Since Germany put forward industrial 4.0, China has also put forward the 'Made in China 2025' plan. With the acceleration of China's automation, China will become a super robot power in the future, and the demand for industrial robots will increase greatly. However, under the stimulation of the high growth of industrial robots, the development of servo motors, the main products of control system and automation, is bound to change. As the power system of industrial robots and the 'heart' of robot motion, where is the future outlet?

According to the Global Industrial Robot Servo Motor Industry Report 2015-2019, China has become the world's largest industrial robot market since 2013, with sales soaring to 55% of global servo motor sales in 2014. It is expected that by 2019, the demand for servo motors in China will reach 182000 sets.

The rapid growth of industrial robots has stimulated the development of servo motor market to a certain extent. According to Researchand Markets, 90% of industrial robots use servo motors. Meanwhile, the number of servo motors assembled by each industrial robot is average. The demand for servo motors increased in 2014 in China at 23100. This figure is expected to reach 737,000 units in 2019.

At present, in China's industrial machinery market, 85% of servo motors are foreign brands, while most of the local enterprises are still at the stage of development and testing, and there is hardly any industrialized industrial robot servo motors.

Coexistence relationship between industrial robots and servo motors

Servo motors are usually installed at the joints of robots. The joint drive of robots can not be separated from servo systems. The more joints, the higher the flexibility and accuracy of robots, the more servo motors to be used.

Robots have very strict requirements for joint-driven motors, so the requirements for electric servo drive systems are also very strict, mainly in the following aspects:

1. Rapid response, the higher the sensitivity of the electro-servo system, the better the fast response performance.

2. The inertia ratio of starting torque is large. Under the condition of driving load, the servo motor of the robot is required to start with large rotation and small inertia.

3. Continuity and linearity of control characteristics. With the change of control signal, the speed of motor can change continuously. Sometimes, the speed of motor must be proportional to or approximately proportional to the control signal. The speed range is wide, and the speed range of motor can be used from 1:1000 to 10000.

4. Small size, small mass and short axial dimension to fit the body of the robot.

5. It can withstand harsh operating conditions, and can carry out very frequent forward and backward acceleration and deceleration operation.

In addition, the domestic servo motor needs to be upgraded, which makes the development of domestic robots difficult. The current situation of domestic servo motors is small, small, big and not big. How to understand this? Small power servo motors can not be miniaturized, generally long, such as 200W and 400W servo motors commonly used in light-duty robots, TBL-imiNI series servo micro motors in Domochuan, Panasonic A6 and Anchuan 7 motors are short and delicate.

On the contrary, domestic servos are generally long and rough in appearance. This is not good for some high-end applications, especially for desktop robots with light load of about 6kg. Because the installation space of the robot arm is very narrow, the length of the servo motor is strictly required.

Secondly, the reliability of signal connectors has been criticized. Domestic servo needs to continue to improve, and connector miniaturization, high-density is also the trend, and the integration design with the servo motor body is a good practice. At present, many Japanese servo motors are designed in this way, easy to install, debug and replace.

Another core technology of servo motor is high precision encoder, especially multi-loop absolute value encoder used in robots, which relies heavily on imports.

Failure to achieve localization is a major bottleneck restricting the development of high-end servo systems in China. Miniaturization of encoder is also miniaturization of servo motor.

The core technology of the past. Throughout the Japanese servo motor product changes, are accompanied by the motor magnetic circuit and coder coordinated development and upgrading!

At present, the domestic OEM manufacturers of servo motors mostly imitate Japanese servo motor design according to market share, and the power is less than 3 kw, mostly small and medium power. But 5.5-15 kW medium and high power servo system did not exist, leading to the application of some equipment, because there is no high-power servo motor and drive matching, and forced to abandon the whole system.

In conclusion, the development mode of Japanese servo system is hierarchical and cooperative development, with excellent overall performance, which is very similar to the development of Japanese robots. In China, it is the motor, the encoder and the driver that make the motor, the encoder and the driver. There is no cooperation, which makes the overall performance of the servo motor and the drive system difficult to do well.

Secondly, basic research on servo system is lacking, including absolute encoder technology, industrial manufacturing technology of high-end motor, breakthroughs in production process, practicability verification of performance indicators and establishment of assessment standards. All these need to be perfected by the core parts enterprises of the robot industry.