Coexistence of industrial robots and servo motors
The servo motor is generally installed at the "joint" of the robot. The joint drive of the robot is inseparable from the servo system. The more joints, the higher the flexibility and precision of the robot, and the more servo motors are used.
The requirements of the robot for the joint drive motor are very strict, so the requirements for the electric servo drive system are also very strict, mainly in the following aspects:
1. Fast response, the higher the sensitivity of the electric servo system, the better the quick response performance;
2. The starting torque inertia ratio is large. In the case of driving the load, the starting of the servo motor of the robot is required to be large, and the moment of inertia is small;
3. The continuity and linearity of the control characteristics. With the change of the control signal, the speed of the motor can continuously change. Sometimes the speed is proportional to the control signal or proportional to the control signal. The speed range is wide and can be used 1:1000~ 10000 speed range;
4, small size, small mass, short axial dimension to match the body shape of the robot;
5, can withstand the harsh operating conditions, can carry out very frequent forward and reverse and acceleration and deceleration.
In addition, due to the domestic servo motor to be upgraded, the development of domestic robots is difficult. The current status of domestic servo motors is that small is not small, big is not big! How to understand this? Small power servo motors, small size is not good, generally long, such as 200W and 400W servo motors commonly used in light-load robots, currently Tamakawa The TBL-imiNI series servo micromotors, Panasonic's A6, and Yaskawa's Σ7 motors are short and exquisite.
In contrast, domestic servos are generally long and have a rough appearance. This is not possible in some high-end applications, especially on desktop robots with a light load of about 6 kg. Since the installation space of the robot arm is very small, the length of the servo motor is strictly required.
Secondly, the reliability of signal connectors has been criticized. Domestic servos need to be improved, and the miniaturization and high density of connectors are also a trend. The integration design with the servo motor body is a good practice. At present, many Japanese servo motors are designed in such a way as to facilitate installation, debugging and replacement.
Another core technology of servo motors is high-precision encoders, especially multi-turn absolute encoders used in robots, which rely heavily on imports. Failure to achieve localization is a major bottleneck restricting the development of China's high-end servo systems. The miniaturization of the encoder is also the core technology for the miniaturization of servo motors. Throughout the changes of Japanese servo motor products, it is accompanied by the coordinated development of motor magnetic circuit and encoder!
At present, domestic servo motor OEMs are mostly based on the market share of Japanese servo motors. The power is mostly within 3kw, and the power is mostly small and medium. However, the medium-to-high power servo of 5.5-15kw is not available, resulting in the application of some devices. Because there is no high-power servo motor and driver matching, it is forced to give up the whole system.
To sum up, the development model of Japanese servo system is layered and coordinated development, and the overall performance is excellent, which is very similar to the development of robots in Japan. In China, the motor is used as the motor, the encoder is used as the encoder, and the driver is driven. Without the synergy, the overall performance of the servo motor and the drive system is difficult to complete.
Secondly, the basic research on the lack of servo system, including absolute encoder technology, industrial manufacturing technology of high-end motors, breakthroughs in production processes, practical verification of performance indicators and formulation of assessment standards. These need to be perfected by the core component companies in the robotics industry.