Question

The best motor choice for robotic arms: servo or stepper? Which type of motor used in robotic arm? Best servo motor for robotic arm.

Which of the following should I choose the best motor for a robotic arm?

A. Servo motor

B. Stepper motor

C. Integrated closed-loop stepper motor

Comments

Which type of motor used in robotic arm?

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Why servo motor is used in robotics? 

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There are many types of motors used in robotic arms to meet the needs of different application scenarios. 

Common motor types include servo motors, DC motors, stepper motors, and brushless DC motors. 

The following is a detailed introduction to these motor types:

1. Servo motor

Features: A servo motor is a motor that can accurately control position, speed, and torque, and is very suitable for joint drive of robotic arms. 

It can provide high-precision position control to ensure that the robotic arm can accurately perform various tasks and actions.

Classification:

+ AC servo motors: have high performance and precision, suitable for applications that require fast response and high-precision control. 

They are usually paired with dedicated servo drives to achieve precise position and speed control.

+ DC servo motors: also common in robotic arms, more economical than AC servo motors, and have good dynamic performance and response characteristics. 

DC servo motors are usually paired with encoders or other position sensors to provide closed-loop control and position feedback.

Application: Widely used in robotic arm application scenarios that require high precision, high speed, and high torque, such as precision machining, medical surgery assistance, etc.

2. DC motor

Features: DC motors have the characteristics of simple structure, large starting torque, and controllable speed, which are very suitable for low-speed and high-torque motion control occasions. 

At the same time, it also has the advantages of strong adaptability and easy maintenance.

Application: In the robot arm, there are a large number of DC motors, which are generally used for the drive control of the robot arm and some key transmission mechanisms.

3. Stepper motor

Features: A stepper motor is a motor that achieves precise position control by moving step by step. It can achieve precise positioning without using position feedback, and the control is simple, but the accuracy and dynamic performance may not be as good as servo motors.

Application: It is suitable for application scenarios that require high-precision positioning but low cost requirements, such as fine operations on assembly lines.

4. Brushless DC motor (BLDC)

Features: A brushless DC motor is a synchronous motor that uses a direct current (DC) power supply, with the advantages of high reliability, no commutation sparks, and low mechanical noise. 

It combines the advantages of DC motors and AC motors, with the good adjustment performance of DC motors and the advantages of simple structure, reliable operation and easy maintenance of AC motors.

Application: In robotic arms, brushless DC motors are suitable for high-speed, high-efficiency, and high-precision motion control scenarios.

Summary

There are various types of motors used in robotic arms, and the specific choice depends on the application scenario, performance requirements, and cost considerations of the robotic arm. 

Servo motors are widely used in high-precision control situations due to their high precision and high performance; DC motors occupy an important position in drive control and transmission mechanisms due to their economy and reliability; stepper motors and brushless DC motors play an important role in low-cost high-precision and high-speed, high-efficiency, and high-precision applications, respectively.

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The main reasons why robots use servo motors are as follows:

1. High-precision position control

Precise control: servo motors have high-precision position control capabilities, which can ensure that robots can achieve extremely high accuracy when performing tasks. This is essential for robot applications that require precise positioning and operation, such as assembly, welding, picking and placing, etc.

Encoder feedback: servo motors are usually equipped with encoders or other position feedback devices, which can monitor the position and speed of the motor in real time and make precise adjustments based on the feedback signal to ensure the accuracy of the robot's movement.

2. High dynamic performance

Fast response: servo motors have a fast response speed and can achieve rapid adjustment of position, speed and acceleration in a short time to meet the robot's requirements for dynamic performance.

Large torque output: servo motors can output large torque to ensure that the robot can still maintain stable performance when performing heavy loads or high-speed movements.

3. Good stability and reliability

Closed-loop control: servo motors use a closed-loop control system, which can make real-time adjustments based on actual feedback signals, effectively suppress external interference and internal errors, and improve the stability and reliability of the system.
Overload protection: The servo motor has an overload protection function, which can automatically stop or slow down when the load is too large to avoid motor damage and robot failure.

4. Flexibility and programmability

Multiple control modes: The servo motor supports multiple control modes, such as position control, speed control and torque control, which can meet the needs of different application scenarios.
Easy to program: The servo motor has strong programmability. Users can write control programs according to specific needs to achieve complex motion control and logic control.

5. Wide application scenarios

Industrial automation: In the field of industrial automation, servo motors are widely used in automation equipment such as robotic arms and automatic assembly lines to improve production efficiency and product quality.
Medical assistance: In the medical field, servo motors are used in surgical robots and rehabilitation equipment to achieve precise motion control, improve the success rate of surgery and patient rehabilitation effects.
Service robots: In the field of service robots, servo motor technology is used in navigation, grasping and interaction to improve the intelligence level of robots and user experience.

To sum up, robots use servo motors because they have the advantages of high-precision position control, high dynamic performance, good stability and reliability, flexibility and programmability, which can meet the needs of robots in various application scenarios.

Answer 1

Answer: A. Servo motor.

Answer analysis: When choosing the best motor for a robotic arm, we need to consider factors such as motor performance, accuracy, dynamic response, cost, and application scenarios.

The following is a detailed analysis of servo motors, stepper motors, and integrated closed-loop stepper motors, and why servo motors are often the best choice for robotic arms.

Servo Motors Vs Stepper Motors Vs Integrated Closed-Loop Stepper Motors

Motor Type	Advantages	Disadvantages
Servo Motors	1. High-precision position control 2. Fast response 3. High dynamic performance 4. Closed-loop control, good stability 5. Multi-degree-of-freedom control, adaptable to complex movements 6. With overload protection and other safety functions	1. Relatively high cost (but still high cost-effective compared with high precision and high performance)
Stepper Motors	1. Combines the cost and simple control of stepper motors 2. Adds closed-loop control to improve stability and accuracy	1. Low accuracy and dynamic performance 2. Open-loop control, less stable than closed-loop system 3. Easy to lose step at high speed or high load
Integrated Closed-Loop Stepper Motors	1. Low cost 2. Simple control 3. Suitable for occasions with low precision requirements	1. Compared with pure servo motors, there is still a certain gap in accuracy and performance 2. There may be a trade-off between cost and complexity

Motor selection for robotic arms

1. Accuracy and dynamic performance requirements

Robotic arms often need to perform complex movements and precise tasks, such as precise positioning, object grasping, assembly operations, etc. These tasks have high requirements for the accuracy and dynamic performance of the motor. Servo motors are very suitable for joint drives of robotic arms due to their high accuracy, fast response, and high dynamic performance.

2. Cost considerations

Although the cost of servo motors is relatively high, considering their advantages in high accuracy and performance, their cost performance is still very high for robotic arms that require high-precision control. 

In addition, with the development of technology and the expansion of production scale, the cost of servo motors is gradually decreasing.

3. Stability and reliability

Servo motors use a closed-loop control system that can monitor and correct the position of the motor in real time to ensure the stability and reliability of the system. This is very important for robotic arms that need to run continuously for a long time.

Best servo motor selection

For robotic arms, the selection of the best servo motor should be based on specific application scenarios and needs. Here are some considerations:

Performance requirements: According to the tasks and precision requirements that the robotic arm needs to perform, select a servo motor with appropriate performance indicators.

Cost-effectiveness: Under the premise of meeting performance requirements, consider the cost-effectiveness of the servo motor and choose a product with high cost performance.

Brand and service: Choose a well-known brand and a supplier with good after-sales service to ensure the quality and reliability of the motor.

In summary, for most robotic arm applications that require high precision, high dynamic performance and stability, servo motors are the best choice. Therefore, among the options given, A. servo motor is the best choice.