Electronic Design
Automotive System-Level Design Needs New Approaches

Automotive System-Level Design Needs New Approaches

General Motors showed off the EN-V outside the Las Vegas Convention Center in conjunction with the 2011 International Consumer Electronics Show in January. The EN-V concept represents a vision of the future of urban personal mobility, including a feature that would allow the vehicle to park itself and automatically return to the user when summoned from a smart-phone application. (photo by Sam Abuelsamid for General Motors)



In the IBM Automotive 2020 Global Study, a European automotive OEM executive says that “in the next 10 years, we will experience more change than in the 50 years before.” That same study, based on interviews with 125 executives from a broad representation of automotive OEMs, suppliers, and influential third parties, concluded that innovation will concentrate on software and electrical systems (i.e., how vehicle occupants can be assisted) as well as powertrain and engine and auxiliary systems (i.e., how the vehicle can be powered).

Today, mid-range to high-range vehicles already run up to 100 million lines of code and may have between 80 and 100 processors and run more than 2000 individual software functions. If that doesn’t scare you yet—while you’re rebooting your phone and your PC just blue-screened—imagine overall electronics complexity and software content growing exponentially.

A recent presentation from General Motors at the 2011 SMART Technology Conference in San Francisco detailed some of the challenges ahead. It predicted that by 2030, 60% of the world’s population will live in urban areas, up from 50% today. Within 20 years, 80% of wealth will be concentrated in cities.

And as the urban population increases, traffic congestion in large metro areas will become an even bigger issue than it is today. In a call for a reinvention of personal mobility in the 21st century, GM identified six main technology drivers: energy, safety, congestion, smart materials, connectivity, and manufacturing.

Future Solutions

What does a potential vehicle of the future look like? A good example is the GM EN-V, the Electrical Networked Vehicle (see the figure). The vehicle looks and feels like a two-seater enclosed Segway that features GPS, a smart phone for remote parking and retrieval, a forward vision sensor for object and collision detection, and forward range sensors for slow speed object and collision detection.

The EN-V drives autonomously so passengers can relax and participate in video conferences with friends and family while on the way to work. It finds parking spots itself and communicates with other vehicles on the road, for example, to negotiate access while approaching intersections.

The challenges for system-level design in systems like the EN-V are huge. Even today, with 80 to 100 processors, vehicles are systems of several subsystems already. Compared to them, our beloved cell phones, tablets, game consoles, tablets, and computers are significantly less complex. The design challenges also span a broader range in cars.

While electric cars have been around basically since the inception of the automobile, combustion engines originally won as the best power system for cars. Advantages at the time included the higher energy content, ease of handling, better price, and abundance of petroleum motor fuel. Vehicles today must be cleaner and more power efficient.

While traditional combustion engines cannot reverse the flow direction of energy, the primary advantage of electric vehicles, both battery electric and hybrid electric, is the bidirectionality of the energy loop. The powertrains of electric vehicles can convert stored energy into vehicle motion as well as convert vehicle motion back into stored energy using regenerative braking. However, the mechanical simplicity of an electromechanical powertrain compared to traditional combustion engines is offset by somewhat more complex electronics to control the motor.

Another key difference lies in the torque generated by the different motor types. Generally, high torque is needed at low speeds for acceleration and less torque is needed at cruising speeds, a requirement that an electric motor fulfills naturally. In contrast, traditional combustion motors develop very little torque at low RPM. Maximum torque can be delivered after accelerating through nearly three quarters of the RPM band. As a result, complex transmission systems are required to match the output of combustion engines to these needs.

This example nicely illustrates system-level design challenges. During the design process, the hardware, software, and mechanics need to be considered in conjunction, leading to a new type of system simulation often called mechatronics simulation.

Mechanical effects can be considered in conjunction with traditional hardware software co-simulation. Early simulation using virtual models or virtual hardware in the loop (VHIL) simulation not only enables an earlier start for software development, it probably more importantly also improves the overall number of tests, resulting in more robust, better tested software code.

Standards And Tools

Not unlike other application areas, standards play a key role for system-level design. To de-couple software from the hardware in automotive applications, the AUTOSAR standard has been developed and will “serve as a platform upon which future vehicle applications will be implemented and will also serve to minimize the current barriers between functional domains. It will, therefore, be possible to map functions and functional networks to different control nodes in the system, almost independently from the associated hardware,” according to the standard. Again, a new breed of system-level design tools will be required, in this case to provide feedback to users about how to map functions to multi-processor systems as early as possible.

As is often the case in very complex systems, tools for the management of systemic complexity will be required as well. Vehicle design is completed by a complex ecosystem of different players—OEMs buying from Tier 1 providers buying from semiconductor providers buying from intellectual property (IP) providers. Managing the complexity of the interaction within the design chain is yet again an area in which a new breed of system-level design tools will increase productivity.

Given the rapidly changing requirements for vehicles, the future looks bright for tool providers in the automotive space. How would you design your concept car? Feel free to contact me with design ideas.

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