Tag: servo motor

Servo motors are mainly classified into DC servo motors and AC servo motors. DC servo motors are divided into brush and brushless motors. Brushed motors have low cost, simple structure, large starting torque, wide speed range, easy to control and maintain (changing carbon brushes), it will generate electromagnetic interference and have specific requirements for the environment. Therefore, it is suitable for common industrial and civil occasions that are sensitive to cost.

The brushless servo motor is small in size, light in weight, large in output, fast in response, high in speed, small inertia, smooth in rotation, and stable in torque. The control is complex and easy to realize intelligence, and its electronic commutation method is flexible, and it can be square wave commutation or sine wave commutation. The motor is maintenance-free, highly efficient, low operating temperature, low electromagnetic radiation, long life, and can be used in various environments.

The servo motor can make the speed and position control accuracy become very accurate, and can convert the voltage signal into torque and speed to drive the control object. The speed of the servo motor rotor is controlled by the input signal and can react quickly. In automatic control systems, servo motors can be used as actuators. Servo motor has the characteristics of small electromechanical time constant and high linearity, and it can convert the received electrical signal into angular displacement or angular velocity output on the motor shaft. It can be divided into two categories: DC and AC servo motors. Its main feature is that there is no autorotation when the signal voltage is zero, and the speed decreases at a uniform speed with the increase of torque.

Servo motor is also called execution motor. Its working principle is similar to that of a two-phase asynchronous motor. However, because it is used as an actuator in a CNC machine tool to convert an AC signal into an angular displacement or angular velocity on the shaft, the speed of the rotor speed is required to reflect the phase of the control signal. It does not rotate when there is no control signal.

Since the two windings on the stator are spaced apart by an electrical angle of 90°, if a symmetrical voltage with the same amplitude and a phase difference of 90° electrical angle is applied to the two-phase windings, a circular shape will be generated in the air gap of the motor. Rotating magnetic field. If the amplitude of the two voltages is not equal or the phase is not 90° electrical angle, the generated magnetic field will be an elliptical rotating magnetic field. If the signal applied to the control winding is different, the ellipticity of the generated magnetic field is also different.

In modern industrial equipment, particularly when using in the high precision conditions, the servo motor technology is developed into high torque density, as a result, the rotation speed may be up to more than 3000 rpm. With the improvement of rotation speed, power density of servo motor is also greatly improved, that means whether a servo motor needs to be matched with a reducer gearbox is mainly determined by the application need and the cost. In following application conditions, a servo planetary reducer gearbox is needed.

Helical slit flexible coupling
Helical slit flexible couplings are usually called as integrated slit cutting coupling or flexible coupling, they often have good performance and cost economy, and are regarded as preferred products in many applications.
The integrated design of a complete aluminum alloy bar makes it to have advantages of zero backlash drive moment and no maintenance. The helical slit flexible couplings can be broadly divided into two basic series: single head helix slit and multi head helix slit. It has large flexibility but low additional bearing load. Such a slit design is particularly suitable for handling the angular deviation and axial deviation, but not suitable for parallel displacement deviation, because the single head helix slit would produce multiple directional bending when handling parallel deviation, which may result in the excessive stress concentration and earlier damage of the parts.
Multi head helix slit coupling reduces the slit length without losing the ability to rectify deviation, the multi head helix slits are intertwined to enhance the torsional rigidity of the coupling, thus ensuring that the coupling can still withstand considerable torque when it has great rectifying capability. This performance makes it suitable for light load applications, such as the connection between the servo motor and the screw. However, such a design also has its shortcomings. The additional bearing load will increase as the size increases. But in most cases, as the installation error is smaller, the bending moment is also very small, thus ensuring low additional bearing load.

What is a servo motor? Servo motor is the motor which controls mechanical components operation in servo system. Servo motor can convert voltage signal to torque and speed, then to drive the control object. The control speed and position accuracy is very high. In auto control system, servo motor can response rapidly as executing component, convert the receiving electrical signal to angular displacement or angular velocity output of motor axis. The main feature is, when signal voltage is zero and no self-rotation, rotation speed will descend at even speed along with the torque increasing. Servo motor has 2 types, DC servo motor and AC servo motor.

Servo driver is a kind of controller used to control the servo motor, which belongs to the servo system. When some problems accur as follow of a servo drive, how we should test and repair? Here are 6 tips  to maintain a servo drive.

Sometimes one has to (still) use a dedicated net just for servos but that is old. Different fieldbuses and/or servo drive interfaces may support a partial frame; for example, one may only be able to set a control word which might be position or torque command while some may support a full parameter frame or command set which exposes a plethora of servo parameters and variations between the two extremes. Speed is also a consideration i.e. may only be fast enough to do motion control or fast enough to close a servo torque loops and/or fast enough to incorporate feedback devices e.g. force or range sensors (without wiring directly to the servo drive).

It depends on specific application situation, and to put it in a simple way: Nature of load (for example, vertical load or horizontal load), requirements of torque, inertia, speed, accuracy and acceleration and deceleration, requirements of upper control (such as requirements of port interface and communication), whether major controlling mode is position, torque or speed mode, whether power supply is direct or alternating current power supply, or battery powered, and voltage scope. Based on this, we can determine models of motor and supporting drives or controllers.

The fluid dispensing machine can be used for adhesive application in most industrial fluids. Most of fluid dispensing machines use stepping drive system, which has low working efficiency and cannot meet manufacturing requirements in some conditions. Using high quality dispensing system can avoid the impacts on quality and productivity of products. Therefore, based on the advantages, AC servo system with motion controller applied to the fluid dispensing machines to improve the quality and efficiency.

Nowadays, with the continuous development of technology, AC servo motor technology gradually replaced the DC motor as the leading executive motor with its excellent cost performance. The mature technology of AC servo system also makes the market develop rapidly and become one of the supporting technologies of industrial automation. So what are the main functions of servo system and how is it classified? Continue and you will learn about that.

Rewinding machine is widely in the re-winding operation and inspection operation of the material in plastics, printing, composite, coating, bag making, and coating film. With double servo automatic tension control, it can operate in the positive and reverse direction. At the same time, it has the fixed point memory stop function, which can quickly reverse to the defect position. The equipment is composed of the unreeling mechanism, take-up mechanism, deviation rectifying device, material delivery guide roller, photoelectric device, tension detection, synchronous strobeflash, length detection, operation interface, electrical control and other parts.

Motion controller usually adapts two types of command mode to control servo motor:
Digital pulse
This mode is similar to the control mode of stepper motor. The motion controller sends"pulse/direction" type pulse command signal to servo driver, when servo driver operates in position control mode, position closed loop is completed by servo driver. This mode of servo motor has the advantages that system debugging is simple and is difficult to cause interference, but has the disadvantage that the response of servo system is slightly slow.
Analog signal
In this mode, motion control system sends/-10V analog voltage command to servo driver and receives position feedback signals from position detection elements, such as motor encoder or linear grating, etc., when servo driver operates in speed control mode, position closed loop is completed by motion controller. Europe and America servo products mostly adapt such operation mode, which has the advantage that response of servo is rapid, but the disadvantage is that they are sensitive to site interference and debugging is complex.

There are some notes for the users when installing and using the servo motor. Take care of servo motor and it can work better and longer. The article briefly illustrates some precations for installation and usage of servo motor from serveral aspects: oil and mater resistant protection, tension reduction for servo motor cable, allowable shaft terminal load and so on.

1. Servo motor does not run when the pulse is output, how to solve the problem?

1. Monitor the current pulse output value of controller and check if pulse output indicator lamp flashes to confirm 
   that the controller has performed command pulse and has output pulse normally.
2. Check if the control cable, power cable, encoder cable between controller and driver are matched incorrectly damaged or contacted poorly.
3. Check if the brake of servo motor equipped with brake has been turned on.
4. Monitor the panel of servo driver to confirm if the pulse command has been input.
5. Run command is normal.
6. For control mode, always choose position control mode.
7. Check if the type of input pulse set by servo driver matches with that of command pulse.
8. Ensure that positive side drive prohibition, negative side drive prohibition signals and deviation counter reset 
   signal are not input and the servo motor runs normally if load is removed, then check the mechanical system.

As the executive element of mechanical equipment, servo motor is used widely in servo system. When using servo motor, there is a phonomena of overheating when working. As you are not familiar with the principle and structure of servo motor, how to judge whether the heating value is normal or not? And how to reduce the heating value of servo motor?

Users often feel confused about the three braking ways of servo motor: electromagnetic braking, regenerative braking, and dynamic braking. As a result, they selected the wrong accessories. The article will tell you the differences among them and give some tips about the accessories selection.

In the specific occasion, when the terminal load is stable, the action is simple and the motor basically runs at low speed, it is appropriate to choose the stepper motor with low cost and easily controlling. However, when terminal load fluctuation range is large, action is simple and the motor basically runs at low speed, if still choosing the stepper motor, a series of troubles are coming. In fact, in such situation, servo motor should be chosen, as the comprehensive cost will decline considering many factors.

Industrial sewing machine control system is a comprehensive and strong technology, which involves many aspects of knowledge, such as the principles of mechanical and electrical equipment, operation technology and so on. As the core running component in industrial sewing machine, the servo system plays a key function in running of this equipment.
This control system mainly includes special controller, AC servo system and stepper motor system, in which the controller mainly consists of main control board and two step drive boards. So it can directly sends pulse to control stepper motors in axis-X and axis-Y, while the needle is controlled by servo motor through needle bar directly connected with coupling.

With global environmental crisis becoming intensified, energy saving and emission reduction has become one target of the automobile industry. Resistance welding and car body manufacturing is inseparable. Depending on its characteristics like wide speed regulation ratio, big rotational torque and high accuracy, resistance welding machines pressed by servo motor plays an important role in welding. It can improve control over welding force and realize accurate control over depth of fusion of welding force and welding points. In addition, servo motor itself has favorable dynamics and it can improve speed from zero to rated speed in several seconds. With its advantages, servo motor has a successful application in resistance welding machine.