Basic knowledge about servo motors
Industrial robots have four major components, namely the body, servo, reducer and controller.
The general structure of an industrial robotic electric servo system is three closed loop control, namely current loop, speed loop and position loop. In general, for the AC servo drive, various functions such as position control, speed control, and torque control can be realized by manually setting the internal function parameters.
So what do you need to know about servo motors?
1. How to choose the servo motor and stepper motor correctly?
A: Mainly depending on the specific application, it is simple to determine: the nature of the load (such as horizontal or vertical load), torque, inertia, speed, accuracy, acceleration and deceleration requirements, upper control requirements (such as port interface And communication requirements), the main control method is position, torque or speed mode. Whether the power supply is DC or AC, or battery powered, voltage range. This is used to determine the model of the motor and the associated drive or controller.
2. Choose a stepper motor or a servo motor system?
A: In fact, what kind of motor should be selected depends on the specific application, each has its own characteristics.
3. How to use a stepper motor driver?
A: According to the current of the motor, a driver with greater than or equal to this current is used. A subdivided drive can be used if low vibration or high precision is required. For high torque motors, use high voltage drives as much as possible to achieve good high speed performance.
What is the difference between 4.2 phase and 5-phase stepper motors? How to choose?
Answer: The 2-phase motor has low cost, but the vibration is high at low speed and the torque at high speed is fast. The 5-phase motor has less vibration and high-speed performance, which is 30~50% higher than that of the 2-phase motor. It can replace the servo motor in some occasions.
5. When is the DC servo system selected, what is the difference between it and AC servo?
A: DC servo motors are divided into brushed and brushless motors.
The brush motor has low cost, simple structure, large starting torque, wide speed regulation range, easy control and maintenance, but convenient maintenance (replacement of carbon brushes), electromagnetic interference, and environmental requirements. It can therefore be used in cost-sensitive general industrial and residential applications.
The brushless motor is small in size, light in weight, large in output, fast in response, high in speed, small in inertia, smooth in rotation and stable in torque. The control is complex, and it is easy to realize intelligence. The electronic commutation mode is flexible, and can be square wave commutation or sine wave commutation. The motor is maintenance-free, has high efficiency, low operating temperature, low electromagnetic radiation and long life, and can be used in various environments.
AC servo motors are also brushless motors, which are divided into synchronous and asynchronous motors. At present, synchronous motors are generally used in motion control. It has a large power range and can achieve a large power. High inertia, the highest rotational speed is low, and it decreases rapidly as power increases. Therefore, it is suitable for applications with low speed and smooth operation.
6. What should I pay attention to when using the motor?
A: Check the following before powering up:
1) Is the power supply voltage suitable (overvoltage is likely to cause damage to the drive module); the +/- polarity of the DC input must not be connected incorrectly, and the motor model or current setting value on the drive controller is appropriate (do not start at the beginning) Too big);
2) The control signal line is firmly connected, and the industrial site should preferably consider the shielding problem (such as using twisted pair);
3) Do not connect the wires that need to be connected at the beginning, only connect to the most basic system. After running well, connect them step by step.
4) Be sure to find out the grounding method, or use the floating.
5) Closely observe the state of the motor within half an hour of starting operation, such as whether the motion is normal, sound and temperature rise, and immediately stop the adjustment after finding the problem.
