replay ： Smart cockpit series article 3 - Behind it 5 Tactile interaction technology

Tips ： A series of questions asked by the interviewer , I couldn't , So come down and recheck yourself , Study and summarize carefully , To cope with more possibilities in the future

About the written examination interview of Internet manufacturers , All need careful preparation
（1） Own scientific research experience , Scientific research content , Relevant field knowledge learned , Be familiar and familiar
（2） My internship experience , Did What content , Domain knowledge learned , Be familiar and familiar
（3） In addition to scientific research , Outside the internship , What I usually pay attention to Cutting edge knowledge , Don't fall , Understand carefully , The interviewer cares about whether you like to catch up with new technology , Follow up on innovative concepts and technologies
（4） Get ready Data structure and algorithm , Big factories with written examinations , The first level is to tear the code by hand to do algorithm problems
During the interview , actually , Prepare data structures and algorithms for emergencies , Have enough confidence to face the algorithm questions that the interviewer may ask , In many cases, your scientific research experience and internship experience are enough to talk to the interviewer , There is no need to test your algorithm . But many big factories will interview you and ask you algorithm questions , So no matter For the written examination interview , Data structures and algorithms must be familiar
Autumn recruit approved many big factories in advance without taking the written exam , Direct interview , Can I go to the interview without written examination , It's up to you Resume strength How strong .

List of articles

• replay ： Smart cockpit series article 3 - Behind it 5 Tactile interaction technology
• • @[TOC]( List of articles )
• Behind it 5 Tactile interaction technology
• summary

Behind it 5 Tactile interaction technology

Obviously, there is an obvious trend in the automotive industry , More and more screens , There are fewer and fewer physical buttons and dials .
As in the previous section （ Smart cockpit series article 2 - Behind it 5 Vision of interactive technology .） Described ,
For the screen , Touch based visual display has become the new normal .
Touch based control in the visual display screen is usually through resistors 、 Capacitance and surface acoustic wave and other conversion mechanisms .
Capacitive sensing is the most popular in touch screens due to its simplicity and multi touch sensing .

However , If visual display is considered , One of his shortcomings is that it may distract the driver ,
So car interaction researchers have begun to explore other intuitive and non distracting ways to provide feedback and interaction to drivers .
This is the time , Tactile or tactile interfaces offer several advantages ：

** Security ：** Auxiliary information can be conveyed to the driver and the completed task , Without scanning any screen , There is no need to look away from the road ;

** Natural control ：** as everyone knows , Using touch control is more intuitive for humans 、 A more natural , And requires less cognitive load ;

** privacy ：** People and cars can communicate discretely , No need to show or publish ;

** More sensitive ：** Human touch sensing has high spatial resolution , And it has been shown that humans can distinguish up to 13 nm The design of ;

** Fast response time ：** It also shows that tactile feedback is faster than visual feedback .

So this article will introduce the intelligent cockpit 5 Tactile interaction, one of the technologies

The technical requirements of internal tactile or tactile interface include :
Large area distributed multimode sensing 、
Good spatial resolution 、
Flexibility and flexibility 、
Fast response time 、
Low hysteresis 、
High durability and stability for repeated contact .

Tactile sensors can be embedded inside the vehicle , Where people usually come into contact , For example, steering wheel 、 instrument panel 、 The seat 、 Headrest, etc . Extracting tactile information requires ：
Dynamic force sensing
Distributed pressure sensing
Contact point positioning
Due to high sensitivity 、 Simple readout electronics 、 Robustness and low power consumption , Capacitive sensing is a popular application .
Extremely thin can be designed by printing conductive materials into stretchable sheets 、 Flexible and stretchable new sensors .
These sensors can be integrated into the vehicle interior with complex shape and structure .
At present, there are applications in the field of robots , This is to return to our previous article KIA Kia automobile 2030 strategic , Kia will invest in robotics .

Similar to capacitive touch sensing , Proximity sensing can detect conductive objects , For example, people close .
therefore , It can be used to detect aerial gestures and touch based gestures .
The capacitive sensing layer can be embedded under the non-conductive material , For example, leather 、 Plastic or wood , These materials are usually found in cars .
for example , As report goes , The active sensing handrail using capacitive proximity sensing combines limb detection and multiple gesture recognition .

Another alternative to tactile feedback is vibratory tactile input , It can be used to remind drowsy or distracted drivers .
for example , Provide the driver with a tactile alarm through the sensing seat , General motors, praised by American consumer reports super cruise One of the highlights is the use of this method , Through the sensors arranged in the seat, directional tactile signals are provided to the user on both sides of the thigh .

A new device that can provide tactile sensing and vibration tactile feedback integrated into a single module is another interesting example .
The vibration tactile component of the device can reach the frequency within the tactile frequency threshold range that can be perceived by the human hand (10–200 Hz) Provide feedback on .
Such devices may be integrated into automotive areas that require sensing and feedback , Such as steering wheel and armrest .
Pressure sensing can also be used in combination with other methods such as temperature .
for example , A multifunctional touch sensitive electronic skin with stacked capacitive pressure sensors and temperature sensors has been reported .
This flexible skin can sense >10 kPa The pressure and up to 80 °C Temperature of , Fast response (2.5 second ) And recovery (4.8 second ) Time .

Monitor human activities through touch （ For example, driver posture monitoring case ） It is necessary to calculate the mechanical strain and deformation .
In this regard , The conductive polymer polystyrene sulfonate is used in the polydimethylsiloxane plate (PEDOT:PSS) The high sensitivity flexible strain sensor of microchannel has attracted people's attention .
This device can also be used as a wearable sensor to measure driver muscle fatigue .
Large tactile displays present in modern vehicles are also used to provide tactile feedback .
for example , Using piezoelectric actuators, the active sensing technology system designed through immersion can provide accurate and high fidelity tactile feedback on the display unit .
Obviously, integrating tactile feedback on a large surface is not easy , Because it needs to accurately calculate the quality of the tactile effect 、 Direction and orientation . Besides , It can also provide tactile feedback on the accelerator pedal and steering wheel , To minimize driver distraction .

Intelligent interactive surfaces provide another new direction , The user interface can be seamlessly integrated into the interior surface of the vehicle ,
These interior surfaces were originally designed for purely aesthetic purposes .
In the past , There is a clear boundary between the inner surface used for decorative purposes and the inner surface that provides control input or feedback output .
However , With the emergence of intelligent interactive surfaces , This clear boundary has recently become blurred , The intelligent interactive surface has control elements integrated into the decorative surface .
For example, there are decorative lighting elements 、 The combination of capacitive switching technology and tactile drive integrated with force sensors embedded under textile materials , Door components for functionalization .
under these circumstances , The capacitive switch function of seat memory and seat heating is only visible when the search light is activated .

Besides , The tactile feedback of the activated switch is supplemented by visual feedback through different switch unit colors .
Such technology can only be used when necessary , And has the function of secret to light .
For example, the control elements displayed in Yanfeng interior are seamlessly integrated into the textiles of seats and other soft interior .
lately ,BMW Smart surfaces for internal and external surfaces are also shown , be called “Shy Tech”.
This smart surface contains cameras 、 Radar and many sensors , With digital function , And has self-healing effect .
Intelligent textiles as sensing elements are also explored to develop intelligent inner surfaces , Because textiles are usually used in car seat covers 、 Safety belt 、 The roof 、 Door panel and instrument panel components .

Capacitive and resistive sensors based on optical fibers are very common .

In capacitive textile sensors , Common methods include single element sensors 、 Conductive fabric stripes 、 Electronic embroidery 、 Printed patterns 、 Coated fibers and hollow structural fibers .

A single element sensor can sense contact at a certain point . An example includes capacitive sensors for seats , The electrodes made of conductive fabric are arranged on both sides of the compressible gasket , Form a variable capacitor .

Hollow structural fibers usually use the air inside the fiber as a spacer , And it is very firm for the typical repeated sitting posture and washing of car seats .
Conductive fabric stripes woven or woven by conductive yarns can also be used as supporting structures and conductive electrodes .
for example , Silver yarn based sensors woven into fabrics have been shown to have low hysteresis ,
Pictured 4c Shown . A conductive ink pattern printed on the fabric to form a small sensing element , It can be scaled at a low cost , Is another attractive way of smart interior .
The printed pattern is also washable . An example of this method is a strain sensor based on printed fabric , It has been proven to measure finger angles and speech 、 The movement of the pharynx when coughing and swallowing .

Another variant of smart textile sensors is based on coated fibers , Among them, the fabric is knitted or woven with special coated fibers ,
And the capacitance change between the two fibers gives a measure of the pressure change , These pressure sensors can be used in conjunction with the vehicle seat to monitor the driver's Ergonomics , Pictured 4a、b.

contrary , Resistive textile sensors usually consist of various screen printed transducer materials 、 Single piece sensor made of electronic embroidery or nanofibers .
Examples include piezoresistive fabric sensors , The transducer material is sandwiched between the non-conductive fabric and the conductive grid structure .
The sensor can detect multiple touch points , It can also be multimodal .
for example , Recently, a stretchable and braidable piezoresistive multimode textile sensor that can be used for distributed pressure and strain sensors has been reported ,
Pictured 4d Shown . This multimodal sensor can be achieved by using innovative methods （ For example, a stretchable antenna is used as a strain sensor ） Wireless data transmission .

in fact , There are other interesting ways , For example, self powered sensors that have been explored in other application fields .
for example , Friction nanogenerators have been shown to exhibit different power outputs when applying loads , This shows that they can be used as energy collectors and pressure sensors .
Considering the growing demand for energy , Such solutions can add significant value to the automotive industry .
Sensors based on conductive cotton and jute fiber and resistance are also explored , For temperature and humidity sensing and energy storage equipment .
Such sensors are made of sustainable materials , It can provide a good solution for interior decoration such as foot mats with relatively thick fibers . Use fiber based supercapacitor mats , An interesting example of distributed energy can be achieved .
Compared with the use of centralized batteries in electric vehicles in the future , Distributed energy can help create more space in the car and improve passenger comfort .
Other examples of vehicle interaction include aerial gestures , At the same time, get realistic tactile feedback without touching any surface .
These technologies can create rich 3D Shape and perceptible texture .
So , Pneumatic and ultrasonic based methods have been explored . In this regard ,Ultraleap and Harman's ultrasonic based IVIS It is worth noting that .
The system responds to the driver's gesture commands through tactile confirmation commands .

summary

Tips ： Important experience ：

1） Behind it 5 Tactile interaction technology
3） Written examination AC, Space complexity can be ignored , But the interview should consider the optimal time complexity , Also consider the optimal spatial complexity .