The Definition of Servo System
The servo system, also known as the follow-up system, is a feedback control system used to accurately follow or reproduce a process. It uses the action of a certain component (such as a control rod) to make the state of the system reach or approach a certain predetermined value, and can compare the desired state with the actual state, and adjust the control component BTS50085-1TMA according to their difference.
Functions and Features
Form speed and position closed-loop control
Methods such as pulse comparison, phase comparison, and amplitude comparison, depending on the principle of feedback
Must handle frequent starts and stops, provide high torque-to-inertia ratio for sufficient acceleration/deceleration, and deliver stable torque at low speeds
Speed servo systems allow converting position control inputs into speed signals to drive the servo motor
Use low-power command signals to control high-power loads
In the absence of mechanical connection, the input shaft controls the output shaft located far away, enabling it to achieve long-distance synchronous transmission
Make the output mechanical displacement track the electrical signal, such as recording and indicating instruments BTS50085-1TMA, etc.
Structure
(1) Detection device
The detection device measures the output physical quantity, compares the actual value of the controlled quantity with the given reference quantity, and calculates the deviation between them. If the measured quantity is a non-electrical parameter, it must generally be converted into an electrical quantity BTS50085-1TMA.
(2) Signal conversion circuit
The control signal of the servo system often needs to be transformed in the form of the signal during transmission. The principle of signal conversion is to ensure that the control signal is not distorted and to effectively suppress noise.
(3) Amplification device
The function of the amplifier is to amplify the error control signal to drive the actuator to control the controlled object. Usually, the amplifier has two stages: voltage amplifier stage and power amplifier stage.
(4) Actuator
The function of the actuator is to convert various forms of input energy into mechanical energy according to the requirements of the control signal to drive the controlled object to work. Actuators are generally various motors and hydraulic and pneumatic servo mechanisms.
(5) Compensation device
The compensation device is also called a correction device. It is a component with a structure or parameters that is easy to adjust. It is connected to the system in series or feedback to improve the dynamic performance of the system and reduce or eliminate the steady-state error of the system. The output of the servo system can be various physical quantities.
Applications
Robotics: Servo systems control the movement of robotic arms and joints.
CNC Machinery: In computer numerical control (CNC) machines, servo systems drive the cutting tools.
Automotive: Servo systems are used in applications such as electronic power steering, throttle control, and automatic transmission systems.
Aerospace: They control the positioning of flaps, rudders, and other control surfaces in aircraft.
Medical Equipment: Servo systems are essential in devices like surgical robots, MRI machines, and patient positioning systems.
Industrial Automation: They are used in conveyor systems, assembly lines, and packaging machines to control the speed and position of moving parts.
Telecommunications: Servo systems help in the alignment and stabilization of satellite dishes and antennas.
Home Appliances: In devices such as washing machines and air conditioners, servo systems manage various mechanical components.
Permanent Magnet AC Servo Motor vs. DC Servo Motor
Advantages:
No brushes and commutators, so reliable operation, low maintenance and maintenance requirements
Stator winding heat dissipation is relatively convenient
Small inertia, easy to improve the speed of the system
Adapt to high-speed and high-torque working conditions
Smaller volume and weight at the same power
Drawbacks:
The permanent magnet AC servo system uses an encoder to detect the magnetic pole position, and the algorithm is complex
The maintenance of the AC servo system is more troublesome because the circuit structure is complex
The reliability of the AC servo drive is not as good as that of the DC servo because the board is too precise
Development Trend
High efficiency: Although this aspect of work has been going on for a long time, it still needs to be strengthened. It mainly includes the high efficiency of the motor itself, such as the improvement of the performance of permanent magnet materials and better magnet installation structure design, as well as the high efficiency of the drive system, including the optimization of the inverter drive circuit, the optimization of acceleration and deceleration motion, regenerative braking and energy feedback, and better cooling methods.
Direct drive: Direct drive includes turntable servo drive using disc motors and linear servo drive using linear motors. Due to the elimination of intermediate transmission errors, high speed and high positioning accuracy are achieved. The characteristics of linear motors that are easy to change shape can make various devices using linear linear mechanisms miniaturized and lightweight.
High speed, high precision, and high performance: Use higher-precision encoders (millions of pulses per revolution), higher sampling accuracy and data bit number, faster DSP, high-performance rotary motors and linear motors without cogging effect, and apply various modern control strategies such as adaptation and artificial intelligence to continuously improve the indicators of the servo system.
Miniaturization and large-scale: Both permanent magnet brushless servo motors and stepper motors are actively developing towards smaller sizes, such as 20, 28, and 35mm outer diameters; at the same time, they are also developing models with larger power and size. The emergence of 500KW permanent magnet servo motors has already been seen, reflecting a trend towards polarization.
Bonus: What Is The Robot Servo System?
A robot servo system is a closed-loop control mechanism that uses feedback to precisely control the position, velocity, and acceleration of robotic joints or actuators. At its core, the system comprises a servo motor, a controller, and a feedback sensor. The controller processes the commands and signals from the sensor to adjust the motor's movement. In practical applications, robot servo systems are generally used in tasks requiring fine control, such as industrial automation, surgical robots, and precision manufacturing.