Role of Bluetooth in Automotive Applications
Bluetooth in cars:
The new generations of cars will have an increasing number of microcontrollers connected through two or more networks. An advantage of this is that the car can be individually customized using software, another that the car can largely have self-diagnostic functions. To fully utilize these functions, it is necessary to have two-way communication between the car system and production tools, as well as service tools to download new programs and parameters and upload status and diagnostic messages. These production and service tools will be based largely on computer technology. The connection between the car system and the tool is made via a cable, either directly to the CAN bus (Controller Area Network) through a gateway. The most economical way is to connect the PC directly to the CAN bus via a drip line, but this has to be short. According to the CAN standard, it should be less than 39 cm at a bit rate of 1 Mbit / s. Compared to USB and Bluetooth, mobility and versatility has a high-performance Bluetooth.
Bluetooth in car production:
In automobile production, a large amount of software is downloaded as a final step on the production line. This is an application where Bluetooth would be ideal. The Bluetooth base station is connected to the production fieldbus. When the car online connects to the Bluetooth base station, it uploads its serial number. The production computer then downloads the software for this same car via the fieldbus to the base station, which in turn transmits it to the car. However, this is dedicated use and no Bluetooth unit other than those installed in cars should connect to the cell phone.
Bluetooth for car service:
A scenario for using Bluetooth could be:
1) When the car enters the gas station, its Bluetooth station contacts the main computer of the gas station. It has previously exchanged information with the car’s computer through the cell phone system.
2) The main computer at the service station alerts the technician who assigned the task and his computer makes contact with the car and downloads the necessary information.
3) The technician obtains the necessary work instructions on his PC. When performing car maintenance, you can control and adjust various functions via PC, for example, any lights, windows, climate control, engine parameters, etc. You can also download the latest versions of software to any Electronic Control Unit (ECU)
CAN / Bluetooth basics:
CAN was developed to be a basis for highly reliable communication over a twisted pair of cables that can be applied from very simple tasks to advanced real-time control. To achieve this goal, it is based on the principle that all nodes in a system simultaneously check each bit transmitted on the bus. According to this principle, a series of problems such as bus access, collision detection, data consistency, etc. they are solved in an elegant way. However, the condition that all nodes see the same bit at the same time requires a controlled wave propagation time. This is easily accomplished in a wired system, but difficult to achieve in a wireless system. Therefore, wireless transmissions in CAN systems must be done through gateways and Bluetooth offers the best possibilities for this task among the available radio standards.
The ideal Bluetooth concept for diagnostics:
The ideal Bluetooth concept for diagnostics should display the following qualities:
1 Low cost
2 Performance as needed
3 standards as required
To achieve these goals we must have a low cost, high performance Bluetooth unit that can be used for any application. Then you have to strip it of everything that is not necessary for everyone, that is, a concept like CAN. It MAY provide the basic functions that any controller network needs, but the remaining necessary functions must be provided by an additional higher layer protocol. The basic block of Bluetooth should deal with the RF part and the essential part of the baseband protocol that is of no interest or is minor for any application, but is essential for the functionality of Bluetooth.
Communication during production:
The use of wireless communication between the vehicle and the production line automation system could open the way to completely new functions in the production process. Depending on the step in the process, for example during final assembly, the vehicle controller and the production line controllers can exchange status information about both the product and the process.
Communication during service:
Potential in-service applications can easily be derived from the scenario for the production process described above. Wireless communication between the vehicle and a gas station computer can be used to exchange status information and service specific information. This step may be supported by a previous data exchange via telecommunications. Wireless communication in combination with a mobile service computer offers optimum flexibility to service personnel.
Advantages and benefit:
The most important advantages of wireless technologies for technical tasks are more or less hidden from the customer of the vehicle. The benefit of such a solution is increased flexibility, modularity and reliability. Although the benefit cannot be directly experienced by customers, it is important to the automotive industry. Furthermore, the potential of wireless communication at the technical task level between smart devices and control units inside the vehicle, as well as control units and human-machine interfaces in the surrounding area of the car, can lead to new functionalities and an increase in flexibility during production and service. The benefit to the customer is increased reliability. For the product development phases, increased flexibility is a huge benefit. A simplified wire harness and wireless interfaces are manufacturing advantages. For service, maintenance and repair, wireless interfaces are advantageous with regard to disassembling and reassembling parts. Furthermore, wireless communication opens up possibilities for flexible connections to human-machine interfaces and diagnostic systems. Although in general an electronic component for a wireless transmission unit is more expensive than a cable, there are several possibilities to reduce the cost of the product, for example, through standardization and reduction of assembly efforts.
Conclusion:
There is a potential of up to hundreds of millions per year of Bluetooth nodes within the vehicle manufacturer market if Bluetooth can be used for real-time control and other technical tasks. For several years, a major trend in vehicle development has been the increasing number of electrical and electronic systems. Many of these systems have been introduced to offer customer innovations through increased functionality, comfort and safety. Another reason is the partial replacement of mechanical components by electrical components or their integration in mechatronic systems.
References
1) Bluetooth in automotive applications
Lars-Berno Fredriksson, KVASER AB
2) The potential of Bluetooth in automotive applications
Horst Wunderlich and Martin Schwab, DaimlerChrysler R&T, Germany Lars-Berno Fredriksson, Kvaser AB, Sweden
3) Optimizing Bluetooth wireless technology
as the ideal interface for car diagnostics -Lars-Berno Fredriksson, Kvaser AB, Sweden