Top 10 Servo Motor Brand & Manufacturers

What is a Servo Motor?

A servo motor is a type of rotary or linear actuator that provides precise control of angular or linear position, velocity, and acceleration. It consists of a motor, a feedback device such as a potentiometer or encoder, and a control circuit. The key characteristic of a servo motor is its ability to accurately maintain a desired position based on an input signal. It is widely used in applications that require precise motion control, such as robotics, CNC machines, and automated manufacturing systems.

History of Servo Motor

• Early Developments: The concept of servo mechanisms dates back to the early 20th century, with the development of electro - mechanical systems for military applications such as gun - aiming and radar - tracking systems. These early servo systems were relatively large and complex, using vacuum tubes and mechanical components. The first servo motors were based on DC motors and were designed to provide accurate positioning in response to an electrical control signal.
• Technological Advancements: With the advent of transistors and integrated circuits in the mid - 20th century, servo - motor technology advanced significantly. The use of solid - state electronics allowed for more compact and reliable control circuits. The development of more accurate feedback devices, such as optical encoders, improved the precision of servo - motor systems. Additionally, the evolution of motor - design techniques led to more efficient and powerful servo motors.
• Modern Developments: In modern times, servo motors have become highly sophisticated. They are available in a wide range of sizes, from miniature servo motors used in small robotics and hobbyist projects to large - scale industrial servo motors capable of handling heavy loads. The integration of advanced control algorithms, such as PID (Proportional - Integral - Derivative) control, and the ability to interface with digital communication protocols like CAN bus and Ethernet have expanded their applications in fields such as automation, autonomous vehicles, and advanced manufacturing.

Purpose of Servo Motor

• Precise Positioning: The primary purpose of a servo motor is to achieve precise angular or linear positioning. It can rotate or move to a specific position with a high degree of accuracy and hold that position until a new command is received. This makes it ideal for applications where exact positioning is crucial, such as in robotic arms for pick - and - place operations or in CNC milling machines for precise tool - path control.
• Velocity and Acceleration Control: Servo motors can also control the speed (velocity) and the rate of change of speed (acceleration) of the movement. By adjusting the control signal, the motor's rotational or linear velocity can be precisely regulated, and the acceleration and deceleration profiles can be customized. This is important for applications that require smooth and controlled motion, such as in conveyor systems or in the movement of robotic joints.
• Closed - Loop Control: Servo motors operate in a closed - loop control system. The feedback device continuously monitors the motor's actual position or other parameters such as velocity and provides this information to the control circuit. The control circuit then compares the actual value with the desired value (setpoint) and adjusts the motor's input to minimize the error. This closed - loop operation ensures accurate and stable motion control, even in the presence of external disturbances such as load changes.
• Dynamic Response and Load Handling: Servo motors are designed to have good dynamic response, meaning they can quickly adjust to changes in the control signal and load conditions. They can handle a wide range of loads, from very light loads in precision - instrument applications to heavy loads in industrial automation. The ability to adapt to different load characteristics and still maintain accurate control is a key advantage of servo motors.

Principle of Servo Motor

• Motor and Feedback Device Interaction: A servo motor typically consists of a DC or AC motor as the actuator. The feedback device, such as a potentiometer or encoder, is coupled to the motor shaft. The potentiometer provides a voltage signal proportional to the shaft's angular position, while an encoder can provide more precise position and sometimes velocity information through digital pulses. The control circuit compares the feedback signal with the input command signal and calculates the error.
• Control Loop Operation: The control loop, usually a PID controller, uses the error signal to adjust the power supplied to the motor. The proportional (P) term of the PID controller provides an immediate response proportional to the error. The integral (I) term accumulates the error over time to correct for any steady - state errors, and the derivative (D) term anticipates the future trend of the error based on its rate of change. By adjusting the gains of these terms, the controller can optimize the motor's response to achieve the desired position, velocity, or other controlled parameters.[!--empirenews.page--]
• Power Amplification and Motor Drive: The control signal from the controller is usually amplified by a power - amplifier stage to provide sufficient current and voltage to drive the motor. The power - amplifier design depends on the type of motor (DC or AC) and the power requirements of the application. For DC servo motors, a DC - DC converter or an H - bridge circuit is often used to control the direction and magnitude of the current through the motor windings.

Features of Servo Motor

• High Precision and Accuracy: Servo motors offer excellent precision and accuracy in position control. They can achieve very small position errors, often within a fraction of a degree or a few micrometers in linear applications. The accuracy is maintained through the closed - loop control system and the use of high - resolution feedback devices.
• Fast Response Time: They have a fast response time to changes in the control signal. The motor can quickly accelerate, decelerate, or change its position according to the new command. This rapid response is due to the efficient control algorithms and the motor's design, which allows for quick changes in the power supplied to the motor.
• Variable Speed and Torque Control: Servo motors provide the ability to control both speed and torque. The speed can be adjusted smoothly over a wide range, and the torque output can be modulated according to the load requirements. This flexibility in speed and torque control makes them suitable for a variety of applications with different motion profiles.
• Overload Protection: Many servo motors come with built - in overload protection mechanisms. If the motor is subjected to a load that exceeds its rated capacity, the control system can detect this and take appropriate action, such as reducing the power or shutting down the motor to prevent damage. This protection feature helps to increase the motor's reliability and lifespan.
• Compact and Lightweight (in some cases): There are servo motors available in compact and lightweight designs, especially the miniature and hobby - grade servo motors. These are suitable for applications where space and weight are critical factors, such as in small - scale robotics, model airplanes, and unmanned aerial vehicles (UAVs).

Types of Servo Motor

• DC Servo Motor: DC servo motors are the most common type. They use a DC motor as the actuator and are relatively simple in structure. The speed and position of a DC servo motor are controlled by adjusting the voltage and current supplied to the motor. They are known for their good speed - torque characteristics and are widely used in applications where a compact and efficient motor is required, such as in small - to - medium - sized robots and automated equipment.
• AC Servo Motor: AC servo motors operate on alternating current. They are often more powerful and have better performance in high - speed and high - torque applications compared to DC servo motors. AC servo motors use advanced control techniques such as vector control to achieve precise motion control. They are typically used in industrial settings for heavy - duty applications such as in large - scale CNC machines and industrial robots.
• Linear Servo Motor: Instead of rotary motion, linear servo motors provide linear displacement. They work on the same principles as rotary servo motors but are designed to move in a straight line. Linear servo motors are used in applications where linear motion is required, such as in precision - positioning stages for semiconductor manufacturing and high - speed linear conveyors.

Precautions for using Servo Motor

• Power Supply Requirements: Ensure that the power supply used for the servo motor is appropriate for its voltage and current requirements. Using an incorrect power supply can lead to improper motor operation, damage to the motor, or even a safety hazard. The power supply should be stable and free from electrical noise and voltage spikes.
• Feedback Device Calibration: The feedback device (such as a potentiometer or encoder) needs to be properly calibrated to ensure accurate position and velocity feedback. Incorrect calibration can result in positioning errors and poor motor performance. Follow the manufacturer's instructions for calibration procedures to achieve the best accuracy.
• Load Considerations: Understand the load characteristics and ensure that the servo motor is rated to handle the maximum load torque, inertia, and other forces. Overloading the motor can lead to decreased performance, overheating, and premature failure. Consider the dynamics of the load, such as its mass and the expected acceleration and deceleration requirements.
• Control Parameter Tuning: The control parameters of the servo motor, such as the PID gains, need to be tuned correctly for optimal performance. Incorrect tuning can lead to instability, overshoot, or slow response. Use appropriate tuning methods, such as trial - and - error, auto - tuning algorithms, or simulation tools, to adjust the control parameters to match the specific application requirements.[!--empirenews.page--]
• Electrical Noise and Interference: Servo motors can be affected by electrical noise and interference from other electrical components or the environment. Use shielded cables for motor connections and power supplies to reduce the impact of electrical noise. Additionally, ensure that the control system and the motor are properly grounded to prevent electrical interference.

Things to consider when purchasing Servo Motor

• Positioning Accuracy and Resolution: Consider the required accuracy and resolution of the position control. Look for a servo motor with a feedback device that provides the necessary precision. The resolution of the encoder or potentiometer and the overall accuracy of the motor's position control should meet the demands of your application.
• Torque and Speed Requirements: Determine the torque and speed requirements of your application. Check the motor's torque - speed curve to ensure that it can provide sufficient torque at the desired speeds. Consider both the continuous torque rating (for sustained operation) and the peak torque rating (for short - term, high - load situations).
• Size and Physical Constraints: Take into account the physical size of the servo motor. Ensure that it can fit into the available space in your application. Consider the motor's dimensions, mounting options, and shaft size and shape to ensure compatibility with your mechanical setup.
• Type of Servo Motor: Select the appropriate type of servo motor (DC, AC, or linear) based on your application's requirements. Consider factors such as cost, power requirements, and performance characteristics. For example, if you need a motor for a small - scale hobby project, a DC servo motor may be sufficient and more cost - effective.
• Control System Compatibility: Consider the compatibility of the servo motor with your existing or planned control system. Check if the motor can interface with the control signals and communication protocols you plan to use. Some servo motors come with built - in controllers or support standard communication interfaces like RS - 232, RS - 485, CAN bus, or Ethernet.
• Cost: Establish a budget for the servo - motor purchase. The cost can vary depending on the type, size, torque rating, and other features of the motor. Consider not only the initial purchase price but also the long - term costs, such as energy consumption and potential maintenance or replacement costs. A more expensive, high - quality motor may be a more cost - effective choice in the long run if it offers better performance and reliability.
• Brand and Reputation: Choose a reputable brand with a good track - record in manufacturing servo motors. Read customer reviews and ask for recommendations from other users or industry experts to assess the quality, reliability, and performance of different models. A well - known brand is more likely to provide reliable customer service and technical support.

Terms of Servo Motor

• Position Error: The difference between the desired position (setpoint) and the actual position of the servo motor. It is a key parameter used to evaluate the accuracy of the motor's position control. The goal of the control system is to minimize this error through the feedback and control loop.
• Torque - Speed Curve: A graph that shows the relationship between the torque output of the motor and its rotational speed. Understanding the torque - speed curve is important for determining the motor's performance under different operating conditions. The curve typically shows that the torque decreases as the speed increases, and it helps in selecting a motor that can meet the load requirements at the desired speeds.
• Feedback Resolution: The resolution of the feedback device (such as an encoder) determines the smallest change in position that can be detected and reported. A higher - resolution feedback device provides more precise position control and is important for applications that require high accuracy.
• Bandwidth: In the context of servo motors, bandwidth refers to the frequency range over which the motor can effectively follow the input command. A higher - bandwidth motor can respond more quickly to changes in the control signal and is suitable for applications that require fast and accurate motion control, such as high - speed robotics and precision - machining.
• Overshoot: Overshoot occurs when the servo motor's position exceeds the desired position during the transient response to a step change in the control signal. Minimizing overshoot is important for applications where precise positioning and smooth motion are required. The control parameters, such as the PID gains, can be adjusted to reduce overshoot.