TDK Develops Magnetic Sensors for Humanoid Robot Joints

This article is reposted from Juncai Magnetic Applications; the copyright belongs to the original author. Please refer to the "Sources" section at the end for the original link.

According to the IT Times on October 20, and as reported by The Elec, InvenSense, a subsidiary of TDK, is developing a low-cost magnetic sensor solution for humanoid robot joints. This approach uses a simple combination of a single magnet and a sensor to measure joint angles, which is expected to replace encoders in certain joints, including finger joints.

A vice president of the company stated at a semiconductor conference for humanoid robots in Seoul that the company is collaborating with robot manufacturers to develop a humanoid robot joint measurement solution based on magnetic sensors.

According to the vice president, humanoid robots have between 20 and 50 joints, distributed across the neck, shoulders, elbows, fingers, and knees. For a robot to lift its arms or grasp objects with its fingers, it must first determine the rotation angle and position of each joint. Currently, this task is handled by encoders, which provide the necessary information for motor control.

The more joints a robot has, the higher the sensor costs. The difficulty is particularly prominent in the finger area: multiple joints are concentrated in a confined space, making the size and weight of the sensors critical considerations. Therefore, selecting different grades of sensors according to precision requirements, rather than installing high-precision encoders on every joint, can effectively reduce costs.

This solution utilizes two types of devices: Tunneling Magnetoresistance (TMR) sensors and Hall sensors. By measuring the changes in the magnetic field generated by the magnets attached to the joints during movement, the rotation angle or displacement can be calculated. Hall sensors can also detect the three-dimensional position of spherical joints. The two operate on different principles: TMR relies on resistance changes caused by the magnetic field, while Hall sensors measure the voltage generated by the magnetic field. TMR offers higher measurement precision.

The company is also developing magnetic encoders for joints that require precise position control. Compared to the simple angle measurement solution, these encoders place greater emphasis on measurement accuracy. The goal is to provide a combination of sensors that covers the motion and performance requirements of different joints.

The vice president noted that in applications where only angle measurement is required, the precision may be lower than that of encoders. However, the sensors are smaller in size, consume less power, and are much cheaper. The company is working with robot manufacturers to implement the solution in areas with relatively lower precision requirements, such as finger joints. Related magnetic measurement technologies have previously been used for angle, position, and current measurement in smartphones and automobiles.

Sources

• m.sohu.com › web (2026-10-19)
• Original link: TDK Develops Magnetic Sensors for Humanoid Robot Joints
• https://m.sohu.com/a/1089924602_121423427/?pvid=000115_3w_a&scm=10001.325_13-325_13.0.0-0-0-0-0-0.5_1334