The role of high-precision TMR magnetic sensors in creating natural robot movements

【Introduction】Today, robots are ubiquitous in our daily life and society. New robots are emerging one after another, such as service robots that can replace humans in welcoming, security, cleaning, etc., and companion robots that behave like family members or pets. What makes these new robots move naturally and smoothly is the combination of motors and sensors that are placed on their bodies. This report will delve into the secrets of the high-precision “TMR sensors” that power robotics.

Robots that replace human jobs are emerging in places as diverse as manufacturing and logistics, medical and welfare facilities, and homes. There are many types, in addition to factory automation equipment and Auto Guided Vehicles (AGVs), there are welcome robots, nursing robots, and communication robots that provide rehabilitation and entertainment at home.

Robots are divided into “industrial robots” and “service robots”. Industrial robots that work on the front line of manufacturing such as factories replace humans to perform prescribed operations in an environment without human contact, while service robots are engaged in services such as welcome and nursing, mainly in public places near humans such as shops and offices. Ensuring safety is a prerequisite for service robots to coexist with humans.

Service robots are gradually becoming popular all over the world. In the future, with the upgrade of sensors and systems, it is expected that new robots will appear and become more and more closely related to our lives.

Various service robots such as companion robots that live together like family members and pets have appeared.

Among service robots, “accompanying robots” that play the role of pets or family members in the home use AI-based chat and smooth motions to even make people forget that they are actually actions performed by machines. It has also gained traction as a way to ease loneliness as human-to-human communication diminishes in today’s society.

The smooth and natural movements of this robot are inseparable from the performance of the motor and components such as the “controller” and “angle sensor” that control the motor. The movable parts of the robot body such as arms, body, and wheels are equipped with small servo motors, and the controller will precisely control the movements of each motor. At the same time, the angle sensor accurately detects the angle and speed of the motor rotation.

In order for small robots such as companion robots to perform natural and accurate movements, it is necessary to make use of high-precision angle detection and high-speed response performance to achieve the best torque response of the motor. Therefore, high-precision angle sensors and small embedded controllers will play an important role. The TAS/TAD series are showing their talents in a wide range of applications including service robots.

In addition, for robots that move autonomously indoors, it is also particularly important to correctly detect the external environment, including room size, surrounding objects, and movement of people and objects. Therefore, the new companion robot is equipped with a large number of sensor elements, including cameras, microphones, temperature sensors, illumination sensors, etc. The miniaturization and high precision of the sensor, and the technology to improve the reliability are all necessary conditions for realizing the high performance of the robot.

New service robots are equipped with dozens of sensors for spatial recognition and motion detection, among others.

Magnetic sensors “TMR sensors” with high accuracy and reliability are used as angle sensors for robot motors. Compared with conventional sensors, it can detect the angle and position of rotating bodies more accurately over a wider temperature range. In addition to robot motors, it is widely used where high-precision magnetic force detection is required, such as angle detection of electric vehicle motors, steering angle detection of electric power steering (EPS), and autofocus functions of smartphone cameras.

TMR sensor to detect the rotation angle of the motor

TMR sensors correctly detect changes in magnetic force by rotating a magnet mounted on the motor shaft.

TDK’s TMR sensors are magnetic sensors that effectively utilize TMR (Tunneling Magnetoresistance) elements, and were originally developed as angle sensors for automobiles and the like. It combines the essence of TDK magnetic technology and thin film technology, with high precision, high reliability and excellent temperature characteristics.

TMR sensors operate stably over a wide temperature range. Therefore, it is also increasingly used as in-vehicle components requiring precision and reliability. In addition, it also has low power consumption performance, and is widely used in consumer products such as robots and smartphones in addition to automobiles.

TDK’s high-sensitivity TMR sensors can be used to control all devices that work with motors, and support future industries and lives with high precision and reliability.

TMR angle sensor TAD2141

The TMR element manufactured by advanced thin-film process technology is a thin-film element with a structure in which a thin insulator layer of 1 to 2 nm is sandwiched between two ferromagnetic layers. TDK’s TMR sensor TAD2141 uses a small package to provide an angle sensor with strong noise immunity, high output, high angular accuracy and high stability. Moreover, the TAD4140 equipped with 2 sensor elements has 2 separate and independent output systems, ensuring the high redundancy required for autonomous vehicles.