Control principle of servo drive
Servo motor, according to the requirements of control commands, amplifies, transforms, and regulates power, making the torque, speed, and position control output by the driving device very flexible and convenient.
Due to its servo performance, it is named a servo motor. Its function is to convert the input voltage control signal into angular displacement and angular velocity output on the shaft to drive the control object.
Servo motors are generally divided into two categories: DC servo motors and AC servo motors.
Servo drives, also known as "servo controllers" or "servo amplifiers," are a type of controller used to control servo motors. Their function is similar to that of a frequency converter acting on ordinary AC motors, and they are part of servo systems. They are mainly used in high-precision positioning systems. Generally, servo motors are controlled through three methods: position, speed, and torque to achieve high-precision positioning of the transmission system. Currently, it is a high-end product in transmission technology.
2. Structure and Principle
The servo drive mainly consists of servo control unit, power drive unit, and communication interface unit. The servo control unit includes position controller, speed controller, torque and current controller, etc.
The servo drive can generally be divided into two modules: a power board and a control board, which have relatively independent functions. The power board is a high-voltage component, which includes two units. One is the power drive unit IPM used for motor drive, and the other is the switching power supply unit that provides digital and analog power to the entire system. The control board is the weak current part, which is the control core of the motor and the operating carrier of the servo drive technology core control algorithm. The control board outputs PWM/PFM signals through corresponding algorithms as driving signals for the drive circuit to change the output power of the inverter, in order to achieve the goal of controlling the AC servo motor.
The servo drive drives the execution motor under the action of control signals, so whether the drive can work properly directly affects the overall performance of the equipment. In a servo control system, the servo driver is equivalent to the brain, and the executing motor is equivalent to hands and feet. The function of a servo driver in a servo control system is to regulate the speed of the motor, therefore it is also an automatic speed control system.
The working principle diagram of the servo drive is shown below:
The core main control board of the driver, which transmits control signals and detection signals through the relay board, completes the dual closed-loop control shown in the figure above, including speed regulation and current regulation, and realizes the speed control and commutation control of the executing motor. The driver board of the driver receives signals from the main control board to drive the power conversion circuit, achieving the normal operation of the executing motor.
Shenzhen Zhongling Technology has currently developed three types of drivers, namely ZLAC8010, ZLAC8015D, and ZLAC8030L. They both support CANOPEN and RS485 control, respectively.
Shenzhen Zhongling Technology (www.zlingkj. com) has many years of industrial control servo technology and rich application experience in service robots and AGVs. It has been researching and developing advanced servo drive control technology, conducting multiple designs and experiments, and has been widely used among many service robot manufacturers. It has the advantages of silence, smooth operation, high stability and reliability, easy installation, and high cost-effectiveness, solving the pain points in the hearts of service robot manufacturers and promoting the development of the service robot industry.
