The motor is a key component of the robot actuator system and is responsible for the movement and control of the robot. Based on electromagnetic principles, motors convert electrical energy into mechanical energy, which in turn powers the physical movement of the robot. Nowadays, robots can perform operations ranging from simple wheel spinning to very complex medical surgeries, a process that is usually controlled by robot controllers, which send control signals to the motors for the purpose of performing these actions. As a result, the motors selected in a robot and their drive solutions largely determine the accuracy, speed, torque, and other important performance attributes of the robot.
Types of motors used in robots
There are various types of motors used in robots, including DC motors, servo motors, and stepper motors, etc. Each of these motors has unique features for a variety of applications.
1. DC Motors
Direct current (DC) motors are very much the type of motors used in robotics, they are simple to use and control and have a good range of speeds. DC motors are further categorized into brushed and brushless types.
Brushed DC motors: these motors consist of a rotating armature, a fixed stator and a commutator. The brushes are in physical contact with the commutator and hence this type of motor is relatively easy to control. However, the brushes need to be replaced from time to time as they wear out over time, resulting in higher maintenance costs.
Brushless DC motors: Brushless DC (BLDC) motors are an example of a type of motor that uses electronic commutation. They use a controller to change the direction of the current instead of using brushes. Because BLDC motors remove the brushes and the only parts that wear out are the bearings, they have better performance, lower electrical noise, and higher reliability. In comparison, brushless DC motors are more efficient, more reliable, and have a longer service life than brushed motors, but brushless DC motors require a hardware/software control system for proper speed and torque regulation, and may be higher in cost than brushed motors.
2,Servo motor
Servo motors consist of a DC motor, gearbox, potentiometer, and control circuitry and are known for their accuracy. The position of a servo motor can be very precisely controlled using pulse width modulation (PWM) signals, making it particularly suitable for applications that require precise motion control.
3,Step motor
Stepper motors work differently from DC motors and servo motors in that they provide excellent control of position and speed with high movement accuracy. Stepper motors utilize a digital control scheme that provides high torque at low speeds, making them ideal for applications that require the load to be held in a specific position for an extended period of time.
I'm sure you've noticed that you rarely see AC motors used in robotics. There are several main reasons for this phenomenon:
First, the control is complicated. DC motors are relatively simple to control; they provide a constant and stable current, making it easy to manage speed, torque and direction. Servo motors and stepper motors are also essentially DC devices that provide superior control of position, speed and acceleration. AC motors, on the other hand, need to rely on the frequency of the AC power supply to control the parameters of the motor, which makes them complex to manage in terms of speed and torque.
Second, the power supply is inefficient. Most robotic systems use batteries as the primary power source, providing DC power. Additional components are necessary to convert DC to AC, which increases the complexity of the motor control system on the one hand and reduces the power efficiency on the other.
Third, there is no advantage in size and weight. DC motors, especially brushless DC motors, can provide a high torque-to-weight ratio, making them more suitable for mobile robot applications. Minimizing weight is a critical consideration in mobile robotics applications. AC motors, especially induction motors, tend to be heavier for the same power output.
Despite these shortcomings, AC motors are sometimes used in some industrial robots for specific tasks that require high power and speed rather than high precision. For example, AC induction motors can be used to drive conveyor belts in automated factory production lines.
The Future of Robot Motor Drives
Motor electronics are moving away from control cabinets and are being integrated directly into robot joints, dramatically reducing robot weight, wiring complexity, and system costs This trend is driving component manufacturers to develop solutions that enable more functional integration in smaller IC packages. At the same time, space constraints also require higher power density and power efficiency for motor drives and controls. GaN FETs with integrated gate drivers can increase power efficiency to more than 99% for motor drive and control solutions in next-generation robots.
Texas Instruments' LMG3422R050 is a 600V GaN FET with integrated driver and protection. The device integrates a silicon driver, and compared to traditional common-source, common-gate approaches, this architecture provides superior switching performance with switching speeds of up to 150V/ns. In addition, this integrated driver protects the GaN device from overcurrent, short-circuit, undervoltage and overheating.
Robotics applications have expanded from manufacturing to industries such as consumer, medical, and even self-driving cars, and next we will see more opportunities for robotics and motor control in new and innovative applications Researchers at Stanford University recently invented a way to enhance the performance of electric motors by using a new type of actuator that allows them to perform dynamic motions more efficiently. With more efficient motors, robots will be able to travel farther and accomplish more tasks, and a robot may even be able to run all day long, rather than only for an hour or two before needing to be recharged, opening up even more application scenarios for the future of robotics!
According to the forecast and analysis by Allied market research, the global robotics market size was estimated at USD 62.75 billion in 2019 and is expected to reach USD 189.36 billion by 2027, growing at a CAGR of 13.5% from 2020 to 2027
In the healthcare industry, in order for surgical robots to function properly, they must utilize advanced motor drive and control solutions that allow for precision movements in order to perform complex and accurate surgical operations In addition to BLDC, servo motors and stepper motors will be increasingly used in next-generation industrial robots due to their precise control, high torque output and fast response time.
Once separate application areas and markets, robotics, motor drives and controls are now increasingly intertwined in the same system Modular and scalable motor solutions are becoming increasingly popular in the industrial robotics motor market, and they offer flexible customization options to meet different application requirements Modular motor platforms can be easily integrated into different robotic systems and scaled as needed, providing significant cost benefits for next-generation robot deployment!
The demand for robot motors market is growing significantly, driven by industrial automation and rapid adoption across industries . According to industry research, the global robot motors market was valued at USD 12.27 billion in 2022 and is expected to grow at a CAGR of 22.44% during the period from 2023 to 2028, to reach USD 41.36 billion by 2028 Driven by the industry's continuous search for high efficiency, productivity, and safety, the new generation of robots equipped with advanced motor
Applications will grow To further expand the application areas of robots, in addition to selecting a motor that optimizes robot performance and efficiency, flexible, efficient and cost-effective motor drive and control solutions also play a key role.