Haptic Technology: Actuators, Types, and How It Works

This page covers the fundamentals of haptic technology and how devices utilizing it function. We’ll explore the different types of haptic actuators, including linear resonant actuators, eccentric rotating mass actuators, and piezo haptic actuators, with a comparison of their features.

What is Haptics?

The word “Haptic” originates from the Greek term “Haptikos,” meaning pertaining to the sense of touch. Touch can trigger a multitude of physiological responses.

Humans possess five primary senses: hearing, sight, taste, touch, and smell. Among these, touch stands out as the most versatile. This sense is capable of providing simultaneous input and output.

About Haptic Technology

• Haptic technology, or haptics, refers to tactile feedback technology.
• It leverages the sense of touch by applying forces, vibrations, or motions to the user.
• This is achieved using haptic actuators, which apply forces to the skin for touch feedback, and controllers. The actuator converts electrical stimuli into mechanical motion as output.
• It serves a similar role for touch as computer graphics does for vision.

Haptic technology is implemented in a broad spectrum of applications, including:

• Mobile devices
• Medical equipment
• Education
• Industrial machinery
• Commerce
• Sports equipment
• Home appliances
• Consumer electronics
• Scientific instruments
• Gaming
• Consumer devices like cameras

How Haptic Technology Works

As touch screens become increasingly prevalent, replacing traditional user interfaces in devices like cell phones, tablets, laptops, desktops, and portable gaming devices, understanding haptics becomes crucial. Haptics offers many advantages, including increased user satisfaction and a more realistic user experience, ultimately improving task performance.

Figure 1 illustrates a simplified block diagram of how haptic technology functions:

• When a press is detected on the touch screen (either by a finger or hand), the touch screen controller sends a trigger signal to the MCU (Microcontroller Unit) or processor.
• This “touch event” signals the MCU or processor to generate a specific waveform.
• This waveform is then fed into a driver IC, which controls the vibrator. The waveform causes the actuator to move in a specific direction or pattern, creating a vibration. This vibration is what the user perceives as a sense of touch.

Comparison of Haptic Actuator Types

The following table compares linear resonant actuators, eccentric rotating mass actuators, and piezo actuators, considering key factors for selection:

• Bandwidth: The frequency range of effects the actuator can produce.
• Response Time: How quickly the actuator can generate a specific effect.
• Mounting: Affects the origin of vibrations and how the user perceives the effects.
• Power Consumption: Dependent on vibration duration and the mass being moved.