#Intensity of piezo disc portable

The picture below is a Stack version of a piezoelectric actuator made by sandwiching piezoelectric material between two metal plates. The bender and stack are the two most prevalent piezoelectric structures.īecause the actuator’s deflection is directly proportional to the control signal, it can be either made to oscillate or hold its position. The most common piezoelectric material for piezoelectric actuators is a kind of ceramic known as PZT. The piezoelectric effect, which causes the material to compress or stretch when an electric signal is applied, is used in piezoelectric actuators to cause vibration. Piezoelectric materials such as ceramics, crystals, bone, DNA and proteins generate an electric charge in response to applied mechanical stress and vice versa. Piezo haptic actuator uses the piezo effect to generate vibration using piezoelectric material mounted in a cantilever beam configuration. Lower vibration amplitude outside resonant frequency due to narrow operating bandwidth Piezo Haptic actuator Advantages & disadvantages of LRAĪdvantages of LRA – More acceleration for the same size compared to ERM, Easy amplitude modulation, LRA consumes less power compared to ERM, quicker response, Smaller in size, high power efficiency due to high Q, Reliableĭisadvantages of LRA – Only vibrates in one axis, Resonant frequency varies between each LRAs, due to manufacturing variations. Apple’s Taptic engine (Source:)Īpple introduced its version of LRA on their devices a few years ago called tactile haptics (shown above). Over the last several years, most phone manufacturers have converted from Eccentric Rotating Mass (ERM) vibration motors to the more efficient, responsive Linear Resonant Actuator (LRA) motors.

#Intensity of piezo disc portable

LRAs are increasingly common in smartphones, small touch screen tablets, portable navigation devices, portable gaming consoles and automobiles for basic vibration notifications. It will result in the magnet moving linearly on the spring, with the displacement will increase and being maximum if the drive frequency matches the resonance frequency of the moving mass. The AC drives the voice coil, which will exert a mechanical force on the mass proportional to the current. The spring constant of the spring defines the resonant frequency of the spring-mass system. Linear resonant actuators haptic (source:)Īs seen in the exploded view of an LRA, a mass and magnet combination is suspended above the voice coil by a wave spring within the magnetic field of the permanent magnet. In its simplest form, it is a spring-mass system where the mass moves linearly back and forth with the help of a voice coil resulting in the desired haptic feedback. Linear resonant actuators (LRA) function like a speaker, which vibrates to send haptic feedback.

Advantages & disadvantages of ERMĪdvantages of ERM – Low cost, widely available, mature technology, Wide range of specifications & simple design and useĭisadvantages of ERM – Vibration signal amplitude relies on driven frequency, High power requirement, slow response (starting and stopping) Linear Resonant Actuators (LRA) While they are not staggeringly cutting edge, they are utilized in the automobile sector to give haptic feedback in touch screen displays and dashboards. They are available in either Coin or Cylinder form with a range of motor technologies, including iron core, coreless and brushless.Įccentric rotating mass vibration motors are cheap to fabricate. Eccentric rotating mass haptic actuator types (image source-ifixit,precisionmicrodrives,google) You can read about how ERM works in a detailed note here. The frequency of the motor influences the amplitude or the vibration strength of the output, therefore producing complex and precise waveforms challenging. Due to its mass and out of balance inertias, an ERM’s starting and shutdown times are comparably slower than LRA or Piezoelectric actuators and in the region of 50 to 100ms. Coreless ERM internal design (Source – )Īs one of the most matured technologies in this haptic feedback, they are available in various power and performance specifications.

As the name implies, the ERM actuators are small magnetic DC motor that spins an eccentric unbalanced weight to create the desired vibrations. There are several more types of actuators used in diverse applications that can be grouped under the six basic types of haptic actuators listed below:Įccentric rotating mass actuators are the oldest and one of the most common types of haptic actuators used in the market today.