Linear Resonant Actuators LRAs

Linear vibration motor(LRA) provides faster response time and longer usage life when compared with ERMs. As such, linear vibration motor(LRA) is more commonly used in handsets, wearable vibration, mobile phone vibration. Moreover, linear vibration motors(LRA) are capable of vibrating at a more steady frequency with less power drain, delivering better quality for the handset haptics experience. The Vertical direction Vibration through electromagnetic force and resonance mode created by sine wave-generated vibrations.

 

Products list

Model

Size

Rated Voltage

Rated Frequency Rated Current Typical Amplitude

Data

Sheet

Order

Samples

NFP-ELV0832A

φ=8mm

T=3.2mm

WL=50mm

AC 1.8Vrms

235Hz 53mA 1.4G Download Buy Online!

 

NFP-ELV1030A

φ=10mm

T=3.0mm

WL=50mm

AC

2.0Vrms

205Hz 75mA 1.7G Download Buy Online!

 

NFP-ELV1030AC1

φ=10mm

T=3.0mm

WL=38mm

AC

2.0Vrms

205Hz 75mA 1.7G Download Buy Online!

 

NFP-ELV1030AL

φ=10mm

T=3.0mm

WL=100mm

AC

2.0Vrms

205Hz 75mA 1.72G Download Buy Online!

 

NFP-ELV1030AC2

φ=10mm

T=3.0mm

WL=38mm

AC

2.0Vrms

205Hz 75mA 1.72G Download Buy Online!

 

NFP-ELV1030AS

φ=10mm

T=3.0mm

WL=10mm

AC

2.0Vrms

205Hz 75mA 1.72G Download Buy Online!

 

NFP-ELV1411A

L=14mm

W=11mm

T=2.5mm

AC 2.0 Vrms 235Hz 53mA 1.5G Download Buy Online!

 

WL: wire length

 

PLEASE  NOTE: 

That all these three LRAs above should be used with a driver IC such as the TI DRV2605L. TI (Texas Instruments) sell an  evaluation board with this IC chip on it. Check the link: http://www.ti.com/lsds/ti/motor-drivers/motor-haptic-driver-products.page

They will not work with DC  battery voltage!!!

 

If you are not quite sure about choosing the LRA(linear resonant actuator) driver, you may lrean from the following link first:

Eight things to consider when choosing haptic feedback - part 1

Eight things to consider when choosing haptic feedback - part 2

All our products are 100% tested by DRV2605(03)EVM-CT. Use the IC DRV2605L - Haptic Driver for ERM/LRA with Built-In Library and Smart Loop Architecture. To learn more about the IC driver from TI: http://www.ti.com/lsds/ti/motor-drivers/haptic-driver-products.page#p2126=LRA, or contact us for help about LRAs.

 

Haptic click carries DRV2605, a Haptic Driver for ERM and LRA vibration motors (acronyms stand for Eccentric Rotating Mass and Linear Resonant Actuator, respectively). The DRV2605 IC integrates an extensive library with over 100 haptic effects. These include audio-to-vibe features, which generate vibrations from the lower frequency range of the audio input (licensed version of ToushSense® 2200 effects from Immersion™).

 

 

Overview of the linear resonant actuator

 

History of the LRA(linear resonant actuator)

The use of ERM vibration motors in personal electronic devices was first pioneered by Motorola in 1984 with the introduction of this feature in their BPR-2000 and OPTRX pagers. Silent call means and compact vibration motor is built and the called communication device to provide a vibration to the user and the feedback. Today there are alternatives such as linear resonant actuators LRA, also know as lra actuator, linear actuator, which offers high reliability in a very small package size. These are typically used as actuators in haptic feedback applications and for basic vibration alert functions.The main applications of the linear vibration motors are mobile phones, smart phones, small devices that require a wearable device and other vibrations.

 

Features and Functions
- Compact / ultra-thin , low-noise high efficiency and reliability, enhanced design drop impact.
- Can accommodate a wide variety of user different kinds of applications.
- Rapid vibration response (Rising time, Falling time) and minimize residual vibration design.
- Low power consumption compared to the vibration characteristics implemented through the low voltage.

- Linear Motor vibrating in direction Z with a very long life time of 1 million cycles at the test mode 2s On 1s Off as one cycle.

- Linear Motor also have a very strong acceleration/ vibration force at its peak acceleration value around 1.7G.

- To use these Linear resonant actuator, users need to add IC drivers in the PCB to activate these motors.

- These LRAs are specially for high-end and high reliable electronic consumer products.

 

Keywords

linear resonant actuator, lra linear resonant actuator, linear resonant actuators, resonant actuator, lra vibration motor, linear actuator, linear actuators, mini linear actuator, linear actuator controller, motor linear actuator...

 

 

Linear resonant actuators (LRAs) driving principle

A linear resonant actuator is a precision vibration motor that produces an oscillating force across a single axis. Unlike a DC eccentric rotating mass (ERM) motor, a linear vibration motor relies on an AC voltage to drive a voice coil pressed against a moving mass that is connected to a spring. When the voice coil is driven at the resonant frequency of the spring, the entire actuator vibrates with a perceptible force. Although the frequency and amplitude of a linear resonant actuator may be adjusted by changing the AC input, the actuator must be driven at its resonant frequency to generate a meaningful amount of force for a large current.

 
How does LRA produces a vibration

 

  • Slim, miniaturized motors are possible due to several patents and structure designing technologies that provide very strong vibration power to the linear vibration motor.
  • linear, actuator, core,tech
linear, actuator, core,tech

The voice coil remains stationary inside of the device while it produces a vibration and presses against a moving mass. By driving the magnetic mass up and down against the spring, the LRA as a whole will be displaced and produce a vibration. The underlying mechanism resembles a speaker producing sound. In a speaker, air is funneled through a cone and displaced at different frequencies by turning an AC frequency and amplitude into a vibrational frequency and amplitude €”internally, a speaker finished this task by moving a magnetic mass with a fast-changing alternating current. Unlike a speaker, which can be driven at arbitrary frequencies, an precision vibration motor is useful in haptic applications within a specific frequency range.

 
Linear resonant actuator electromagnetic force

 

 

Rather than directly transferring the force produced by the voice coil to the skin, the device optimizes for power consumption by taking advantage of the resonant frequency of the spring. If the voice coil pushes the magnetic mass against the spring at the spring’s resonant frequency, the device can produce a vibration of higher amplitude more efficiently. Since the voice coil is driven by an AC current, modeling the desired frequency and amplitude of vibration, the frequency and amplitude may be independently modified. This is different than an ERM motor, which couples the two properties of the resulting vibration.

 
How to controll the LRA's frequency to optimize its power consumption?

Although the frequency can be changed, the LRA (linear resonant actuator -linear vibration motors) will typically be operated within a narrow frequency range to optimize its power consumption €”if the device is driven at the resonant frequency of the spring, it will consume less power to produce a vibration of equal magnitude. Regardless, this improvement alone presents a unique advantage over ERM motors: a precise waveform of varying intensity over time can be reproduced in an precision vibration motor with a fixed frequency, whereas a waveform of varying intensity in an ERM motor will also produce a varying frequency of vibration. UI/UX support for high usability due to various haptic effects. High vibration force touch, ultra-slim form factor, low current consumption. Real haptic feedback provided by various haptic patterms.

 
Linear resonant actuator compoments

 

The functions of individual parts

Parts Function
Case Fixes the spring
Spring Decides the weight and frequency
Yoke Magnetic field path
Weight Decides the spring and frequency vibration force in propotion to the mass of weight
Magnet Applies electromagentic force to the coil

Coil

Applies electromagnetic force together with the magnet
Bracket Fixes the coil and FPC

The typical start time for an linear vibration motor is approximately 5-10ms, a fraction of the time required to produce a vibration with an ERM motor. Spring design and stress analysis. Electro-magnetic field design. Fast response time, control of vibration force for long life. This incredible speed results from the immediate movement of the magnetic mass as current is applied to the voice coil inside of the device. In an ERM motor, the precision vibration can only be produced after the motor reaches its operating speed €”even when over-driving the linear vibration motor to produce faster acceleration, the motor can require 20-50ms before reaching a desired intensity of precision vibration.The stop time of an LRA can be significantly longer than an ERM motor. An linear vibration motor can take up to 300ms to stop vibrating due to the continued storage of kinetic energy in the internal spring during operation. Thankfully, an active braking mechanism can also be used for an precision vibration motor (vibration actuator) €”by performing an 180-degree phase shift of the AC signal provided to the actuator, the precision vibration can be stopped very quickly (within approximately 10ms) by producing a force touch opposite to the oscillation of the spring.

 

Applications of linear vibration motors

 

  • 1. Maps: Maps are one of the most important functions utilizing haptics, as the “Maps” app on the is capable of giving directions by providing tactile feedback on each turn so the user knows which direction to turn.

     

  • 2. Heartbeat: The haptics will perform the simulation of heartbeat. Users can send the Heartbeat vibration from one to another.
  •  

    3. Notifications : also utilizes the for notifications and confirmation purposes. For example, when a Pay transaction goes through, users will feel a pulse on their wrist indicating that the payment was successful.

 

LRA related patents

 

Immersion Corporation


 

US12336231

A system that generates a haptic effect generates a drive cycle signal that includes a drive period and a monitoring period. The drive period includes a plurality of drive pulses that are based on the haptic effect. The system applies the drive pulses to a resonant actuator during the drive period and receives a signal from the resonant actuator that corresponds to the position of a mass in the actuator during the monitoring period.

 

US11748219

A haptic feedback system that includes a controller, a memory coupled to the controller, an actuator drive circuit coupled to the controller, and an actuator coupled to the actuator drive circuit. The memory stores at least one haptic effect that is executed by the controller in order to create a haptic effect.

 

US11291207

Systems and methods for controlling a resonant device are described. One described method for braking an actuator includes generating a first actuator signal configured to drive the actuator, the first actuator signal having a first frequency approximately resonant to the actuator, and transmitting the first actuator signal to the actuator. The method also includes generating a second actuator signal, having a second frequency approximately 180 degrees out of phase to the first frequency, the second actuator signal configured to cause a braking force on the actuator, and transmitting the second actuator signal to the actuator.

 

US11733453

A haptic feedback generation system includes a linear resonant actuator and a drive circuit. The drive circuit is adapted to output a unidirectional signal that is applied to the linear resonant actuator. In response, the linear resonant actuator generates haptic vibrations.

 

PCT/US2005/043583

Systems and methods for controlling a resonant device are described. One described method for braking an actuator includes generating a first actuator signal configured to drive the actuator, the first actuator signal having a first frequency approximately resonant to the actuator, and transmitting the first actuator signal to the actuator. The method also includes generating a second actuator signal, having a second frequency approximately 180 degrees out of phase to the first frequency, the second actuator signal configured to cause a braking force on the actuator, and transmitting the second actuator signal to the actuator.

 

Texas Instruments, Inc


 

US13443741

A method for driving a Linear Resonant Actuator (LRA) is provided. During a first off interval, the back-emf of the LRA is measured. During a first off interval, a timer is started when the back-emf reaches a predetermined threshold, and after a predetermined delay has lapsed following the back-emf reaching the predetermined threshold during the first off interval, the LRA is driven over a drive interval having a length and drive strength. A second off interval is entered following the drive interval, and during the second off interval, the back-emf of the LRA is measured. During the second off interval, the timer is stopped when the back-emf reaches the predetermined threshold. The value from the timer that corresponds to the duration between the back-emf reaching the predetermin -ed threshold during the first off interval and the back-emf reaching the predetermined threshold during the second off interval determines the length.

Contact us

Considering LRA motors?

 

Email at us:

info@nfpmotor.com

nfpmotor@gmail.com

 

Or call us at: +86(0)186 6003 7716

 

Applications

vibration motor pcb mounted vibration motors 3V DC vIbration motors
NullSpace Suit VR - feel virtual reality

Feedback pads with 32 independently activated vibration pads(micro vibrating motor) on the chest, abdomen, arms, shoulders, and hands.

 

car automotive gear motor automobile dashboard gera reduction motor

Axon Body 2 - police equipment

Vibrating Motors will be used for alerting when men in a very special environment, or exceptional circumstances.

 

vibration motor pcb mounted vibration motors 3V DC vIbration motors

White goods & other industrial
As industrial human machine interfaces (HMI) start to develop more tablet-like control panels, the number of the touch screens used in industrial applications is increasing.

 

vibration motor pcb mounted vibration motors 3V DC vIbration motors
Vibrating Underwear

The vibrating underwear announced by condom-maker Durex nearly has clearly touched a sensitive nerve around all over the world.

 

vibration motor pcb mounted vibration motors 3V DC vIbration motors
Medical Care

Portable medical devices often use the audible or visual alerts(by vibrating motors) to notify the ineed patient of potential issues.

 

vibration motor pcb mounted vibration motors 3V DC vIbration motors
Automotive - vibrating alert, touch screen

A major drawback of touch controls is the lack of tactile feedback. This can lead to the driver taking their eyes off the road to see if their input was accepted.

 

vibration motor pcb mounted vibration motors 3V DC vIbration motors

Personal electronics
By adding haptic effects, the personal electronics manufacturers can offer their product with tactile feedback rather than just audible feedback.

 

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