Working principle of open loop stepping servo motor system
The working principle of open-loop stepping servo motor system, stepping motor servo system is a typical open-loop control system, the command signal is unidirectional flow.
The open-loop system has no position and speed feedback loop, eliminating the detection device, its accuracy is mainly determined by the stepping motor, the speed is also limited by the performance of the stepping motor, and the system is simple and reliable, there is no need for complicated design calculation and experimental verification like closed-loop servo system.
Stepping Motor open-loop servo system has a series of advantages such as simple structure, convenient use and maintenance, high reliability, low manufacturing cost, etc. In small and medium-sized machine tools and occasions with low speed and precision requirements, it has been widely used. 1.
There are many types and structures of stepping motors. According to different classification methods, stepping motors can be divided into various types, as shown in Table 1.
Analysis of open-loop servo system of stepping motor, working principle of open-loop stepping servo system, stepping motor is divided into stator and rotor in structure, now the reactive three-phase stepping motor shown in Fig. 2 is taken as an example to illustrate.
There are six magnetic poles on the stator, each magnetic pole is wound with an excitation winding, and each opposite two magnetic poles form A phase and are divided into three phases: A, B and C.
Five small teeth are opened on each magnetic pole of the stator, the tooth widths are equal, and the included angle between the teeth is 9.
The rotor has no winding and is made of a toothed core.
There are 40 small teeth with uniform distribution, and the angle between teeth is also 9.
In addition, the small teeth on the stator magnetic pole are staggered by 1/3 in spatial position.
Analysis of open-loop servo system of stepping motor, working principle of open-loop stepping Servo System 2.
The working principle of stepping motor, stepping motor works according to the principle of electromagnetic attraction, now taking reactive stepping motor as an example to illustrate its working principle.
The stator of the reactive stepping motor has magnetic poles, each magnetic pole has excitation winding, the rotor has no winding, has teeth evenly distributed in the circumference, and relies on the attraction of magnetic poles to teeth.
As shown in Fig. 3, the three-phase stepping motor has three pairs of magnetic poles on the stator and is divided into three phases: A, B and C.
Analysis of open-loop servo system of stepping motor, working principle of open-loop stepping servo system, open-loop servo system of stepping motor and open-loop control numerical control machine tool are shown in Figure 1. Features: simple structure, stepping Drive, stepping motor, no position speed feedback.
Analysis of open-loop servo system of stepping motor, working principle of open-loop stepping Servo System 1.
Structure, the stator and rotor cores of the motor are usually made of silicon steel sheets. The stator and rotor are evenly distributed with many small teeth.
There are three pairs of magnetic poles A, B and C on the stator, and A, B and C three-way control windings are wound on the corresponding magnetic poles.
Its geometric axis is staggered with the rotor tooth axis in turn. See Figure 2-5-6. 2.
Working Principle, stepping motor is a kind of motor that converts electrical pulse into angular displacement.
A special driving power supply is used to supply a series of regular electric pulse signals to the stepping motor. Each input of an electric pulse, the stepping motor takes one step forward, and its angular displacement is proportional to the number of pulses, the motor speed is proportional to the pulse frequency, and the speed and steering are related to the power-on mode of each phase winding. 3.
The operation mode of stepping motor is: Three-phase single three-beat, three-phase double three-beat and three-phase six-beat.
The angle at which the stepping motor rotates for each input pulse signal is called the step angle to & theta; S indicates.
Step distance error refers to the difference between the actual rotation angle of each step of the rotor and the theoretical step distance angle when the stepping motor is running. 4.
Stepping motor power drive, drive control circuit consists of ring divider and power amplifier. (1)
The ring distributor the ring distributor is used to control the power-on mode of the stepping motor, and its function is to add a series of command pulses sent by the numerical control device to the power amplifier according to a certain sequence and distribution mode, control the power-on and power-off of each phase winding.
The ring distributor function can be generated by hardware or software. See Figures 2 and 3.
Analysis of open-loop servo system of stepping motor, working principle of open-loop stepping servo system, analysis of open-loop servo system of stepping motor, working principle of open-loop stepping servo system (2)
The drive amplification circuit diagram 4 is a high and low voltage drive circuit.
Features: high voltage charging, low voltage maintenance.
Analysis of open-loop servo system of stepping motor, working principle of open-loop stepping servo system, Fig. 4 high and low voltage driving principle 5. Main features (1)Maximum static torque Tmax (2)Startup frequency (3)Continuous operating frequency (4)Moment frequency characteristics (5)Static step moment error 6.
Selection of stepping motor stepping motor has step angle (Involving Phase number), Static torque, and current.
Once the three elements are determined, the model of the stepping motor is determined.
TAG open loop stepping servo motor