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    Saving lives with
    ultra-precise sensors
    - ten times more accurate
    in just a decade

    Sensors are able to detect what humans can with their eyes, ears, nose, skin, tongue, etc. - then convert that information into electric signals. Sensors come in many forms - from temperature sensors in air conditioning systems to human sensors for automatic doors, and haptic sensors for touch-based control of tablets and computers. In this article, we focus on inertial sensors - critical for autonomous driving, drone control, and other advanced applications that are part of our everyday lives. We spoke with Mr. Kato, who leads product technologies, and Ms. Nishimura, who oversees development, about their vision for "Small is Dynamic" - future innovations enabled by miniature capacitors.

    Mr. Kato (left) and Ms. Nishimura (right) of the Functional Devices Division, Communication & Sensor Business Unit

    Ensuring the safety of
    autonomous vehicles
    and drones through precise motion measurement

    --- What kind of role do inertial sensors play?

    Kato: Many people may not have heard of "inertial sensors," which measure object motion (acceleration and rotation). They are used in all kinds of situations in our everyday lives. A familiar example might be the shake correction feature in digital cameras. Blurring is reduced by slightly adjusting the lens to neutralize the camera shaking detected by the sensors. An "inertial sensor" measures the location, direction, position, and speed at which objects are moving.

    Nishimura: They measure object motion, but the purpose of the product determines "which motion" of "which axis" is sensed. Past sensors only measured the axis of motion direction. Newer functions, such as autonomous driving and drone operation, require safety and convenience. Sensor data from inactive axes is used to confirm overall sensing accuracy. As a result, the types and numbers of axes and movements subject to measurement have increased.

    Kato: For example, Inertial sensors are used in the side-slip prevention function to maintain cars in a steady position, as well as in the flight control units of industrial drones that measure, inspect, and spray pesticides - just some of their many uses. They're also integrated into structures like bridges and tunnels to detect tilts or shifts - ensuring safety during construction and supporting maintenance afterward.

    In addition to major improvements in precision,
    durability to maintain quality over long-term use
    was also essential.

    Kato: Our inertial sensor successfully improved precision tenfold in ten years. When moving 100 meters with autonomous driving, "precision tenfold" means being off by less than the width of a tire vs. being off by half the auto body, as it was previously.

    With self-driving cars, it is crucial to correctly detect the car's position (tilting) and direction of movement. Without this, the car cannot drive as intended. When walking, we humans use our eyes to monitor our surroundings and maintain our course; if we veer off track, we naturally correct it. But if you walk with your eyes closed, you might think you are walking in straight line, but you can gradually veer off course. Self-driving cars face the same issue. Cameras detect the surroundings, but in a low-visibility environment, such as a tunnel or a dense fog, visual information alone can impair accurate detection. To drive reliably in such a situation, inertial sensors play a key role. Even if the deviation is slight, it grows as the driving distance increases. This is why high-precision sensors are vital.

    Nishimura: Exactly. And cars are constantly exposed to harsh temperature environments and vibration. They are also expected to operate continuously for long hours. Maintaining precision in these conditions requires very high levels of endurance and reliability. At Murata, our sensors undergo strict verification in the design stage. We conduct rigorous testing to ensure that standards are met, such as checking the effects of extended exposure in high-temperature environments and extreme temperature fluctuations.

    Kato: With this component, lives could be at stake in the rare event that a defect occurs and goes unnoticed. To ensure the safety of the overall system, we embedded a mechanism that issues an alert if an error or failure occurs in the sensor.

    Even more precise, even smaller.
    To protect the lives of people
    around the world

    --- What does "Small is Dynamic." mean in the context of inertial sensors?

    Nishimura: Every effort we've made to enhance sensor accuracy runs counter to the goal of reducing their size. When we enhance durability while maintaining high precision, sensors become larger. In fact, the inertial sensors introduced around 1950 were large devices weighing over 50 kilograms. But with advanced technology today, sensors with the same level of precision are small enough to fit on your fingertip. I think this is an amazing advancement of technology.

    Sensors that used to weigh about 50 kilograms are about 1 cm today (left). The latest sensor on the bottom right is very small compared to past sensors (right).

    Kato: Some people may wonder, "Isn't there plenty of space for components in cars and drones?" There isn't just one sensor in a car - multiple components rely on them, including the ECU (electronic control unit), airbags, and headlights. Miniaturization is critical to ensure sensors fit into designated spaces without altering the vehicle's design. Processing accuracy for sensors is measured in microns - one digit smaller than the thickness of a single hair, which is 0.08 mm. This is truly "small."

    Inertial sensors play a vital role in ensuring safety and security in the future mobility ecosystem, which will include autonomous vehicles and drones. By instantly detecting what humans cannot, they can help to realize an accident-free world. In the sense that inertial sensors protect human lives, they have a huge impact on society overall and I believe they can be considered "dynamic."

    Nishimura: As they have become smaller, inertial sensors are now used also in smartphones, game consoles, and more. I believe that their use will eventually spread even more. One day, they may be able to act as a "sixth sense" that transcends the human senses. When they become able to sense subtle changes in gravity and airflow, which are difficult to express in numbers and language, they can detect danger that would go unnoticed by humans. Miniaturized sensors in wearable devices can monitor physiological changes caused by stress or tension, providing valuable insights that support mental health. The immense potential of small parts-this is certainly "dynamic."

    Its size: smaller than 1/10,000 of a grain of rice.
    Using small power to support the world
    and to explore space     Saving lives with ultra-precise sensors
    - ten times more accurate in just a decade

    More Information

    Murata SCH1633-D01 Sets a New Standard for Automotive 6DoF Sensor Open in new window

    Pursuing Higher Precision in Inertial Force Sensors for Safe Self-Driving Cars (Part 1 of 2) Open in new window

    Gyro Sensors Open in new window

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