How to design the human-computer interaction of car computers?

We have discussed more than once what conditions are needed for an excellent in-vehicle HMI human-machine interaction system. In short, a reasonable combination of software and hardware is an essential basic part.

For example, the most intuitive things we feel in the car are the interactive media such as the central control panel, various buttons and instrument panel. Whether the design of this hardware system is reasonable directly determines the ease of use and safety of users.

Intelligence is the trend

As your car becomes smarter, users have more and more expectations for it. Questions like, "His car has a big screen, why doesn't mine?" are appearing more and more frequently. An obvious trend is that if a car does not have a large screen that can be connected to the Internet and the various services derived from it, then the car is far from being smart enough for users to perceive.

In the coming period of time, large screens will gradually become standard for cars. Therefore, an excellent in-vehicle HMI will have an increasingly greater impact on users' car purchasing decisions. In other words, this puts forward more requirements for both OEMs and suppliers in the industry.

At the GAME Future Mobility Conference held by GeekCar in early September, a car networking company talked to us about their in-vehicle HMI planning. This company is Jidou. We first learned about them when Jidou released the aftermarket smart car machine two years ago. Recently, they have begun to cooperate with OEMs to develop pre-installed.

For aftermarket car machines, since it is impossible to fully define the overall HMI style in the car, it is more like dancing with shackles. Therefore, when designing, more improvements are needed to make up for such "innate deficiencies". Therefore, Jidou has richer design experience than the team that only focuses on pre-installation. This time, I happened to have the opportunity to learn from Jidou's HMI team how they designed the in-vehicle human-computer interaction.

How to design it specifically?

In terms of specific products, the core of Jidou's previous products was the in-car navigation and the software and hardware systems behind it. Therefore, almost all interactions were concentrated on the central control screen and the derived voice, button and other operation levels.

Therefore, when designing the large-screen UI, Jidou has used the left-side shortcut menu interaction method since DouUI 2.0 released in 2015. User feedback and test research also found that the left column is closer to the driver (only for left-hand drive cars) and is more convenient for operation. In fact, Android Auto has always placed the shortcut keys at the bottom of the screen, which not only increases the driver's operating burden, but also compresses the height of the visible area of ​​the in-car navigation. However, at this year's Google I/O 2017, the Audi customized in-car navigation displayed by Google also placed the shortcut keys on the left, which also indirectly confirmed the feasibility of this interaction method.

In addition to the basic desktop layout, the way information is presented also needs to be designed in detail. For example, when Google designed the in-car HMI, it mainly displayed information in the form of cards. The advantage of this is that it can display more information at the same time, which is convenient for users to operate. However, this design makes some applications open for a long time, which will occupy some content space, and it also has high requirements for the hardware configuration of the in-car navigation.

Jidou uses another presentation method, which is an icon display method that is more in line with mobile phone usage habits. Unlike cards, the advantages of icons are high user acceptance, low learning cost, and the same size screen can carry more App entrances. However, the information display effect of a single entrance is relatively limited. In addition, Jidou has also designed a screen saver function to reduce information interference when users do not need to view the screen.

The notification bar is actually a key function for in-car interaction to provide real-time status feedback. The floating design adopted by Jidou also serves as the desktop navigation floating frame to meet the user's needs for performing other operations during navigation.

In the design of entertainment systems, we mainly take music and FM as examples.

There are three main ways for users to obtain music: CDs, USB flash drives and online songs. Currently, due to the reduction of 4G network charges, online music listening has gradually become the mainstream.

The design basis of Jidou Music App is mainly based on three points:

Fastest - the fastest way to achieve user operation and goal; Least - retaining only the least visual interference factors; Optimal - the optimal interaction solution combined with the in-vehicle experience.

In addition, the App also retains music playback and list display to meet the basic needs of users. The design of the FM App continues the interactive mode of music, which can minimize the learning cost of users.

What other design principles are there?

Jidou's HMI team also introduced some other relevant design principles.

The first is color. Reasonable design has a key impact on user vision. After all, if you can't see clearly when using navigation, it will affect driving safety.

Regarding the choice of color saturation, high-saturation colors can effectively guide users to operate the interface, but they will cause visual interference. Therefore, high-saturation colors need to be used in specific locations and reduce the user's dwell time. However, in fact, low-saturation colors are the more common color selection scheme for in-vehicle HMIs, which can effectively relieve users' visual fatigue caused by long-term use of navigation.

In addition, the interference of bright and dark light on vision also needs to be carefully considered. The driving environment is diverse and more demanding than the use scenarios of mobile devices. It is mainly divided into the following categories (lx is the unit of lux):

1. Twilight period: The period of time when there is light, including the morning and afternoon sunlight, but the sunlight is not strong, with reference to lux ≤ 20,000 lx.

2. Strong brightness period - scenes with direct sunlight, calculated as above 20,000 lx;

3. Dark period - the night without sunlight, with ≤0.2lx as the benchmark;

4. Indoors - In bright rooms, 100 to 550 lx is the standard;

The in-car navigation is mainly classified into the daytime corresponding to the dim period and the night corresponding to the dark period.

Due to the outdoor reflection phenomenon, the twilight period has a greater impact on HMI design. Jidou's design idea is to use high-contrast visual designs close to pure white as much as possible. This is because pure white background and black text have better adaptability to reflection under the same test environment. At night, the driver is in a dark room environment, which is conducive to observing the road conditions outside the car. Therefore, HMI design needs to optimize the corresponding night mode design on the basis of reducing the screen brightness. The specific method is to avoid unnecessary bright color block design elements as much as possible, and the content design uses a black background with low-brightness colors.

Finally, the design style. Previously, OEMs mainly used skeuomorphic designs with a heavy texture. In recent times, there has been a trend towards a flat style. When designing HMI, in addition to considering the design specifications of the Android system (currently the mainstream operating system for aftermarket), it is also necessary to pay attention to the optimization of in-vehicle operations.

Of course, an intelligent in-vehicle interactive system must also have the ability to expand and upgrade. In addition to online OTA, by connecting with mobile phones, users can remotely control some vehicle functions, seamlessly switch navigation, directly transmit data and other functions, which can also greatly improve the user experience.

As software and hardware infrastructure and Internet service capabilities continue to change, user needs will also undergo unpredictable changes. For in-vehicle HMI design, although the principles can be followed, many details also need to be adjusted according to actual conditions.

In short, a good in-vehicle HMI design needs to meet the user's needs for safety and ease of use to the greatest extent possible within its capabilities. This makes no essential difference to any participant.

Recently, Jidou has also launched Apple CarPlay accessories, which support iPhones with iOS 9.3 or above. For users who want to experience Carplay, this is also a good opportunity. You can visit Jidou's official website for more information.