Bluetooth in the car:
The new generations of vehicles will have more and more microcontrollers that are connected via two or more networks. One advantage of this is that the car can be customized via software, another is that the car can largely have self-diagnostic functions. To take full advantage of such functions, two-way communication is required between the vehicle system and production tools as well as service tools for downloading new software and parameters and uploading status and diagnostic messages. These production and service tools will be largely based on PC technology. The vehicle system and tool are connected via a cable, either directly via a gateway to the CAN (Controller Area Network) bus. The cheapest way is to connect the PC directly to the CAN bus via drip line, but this must be short. According to the CAN standard, it should be less than 39 cm at a bit rate of 1 Mbit/s. Compare with USB and Bluetooth, the portability and versatility has made Bluetooth highly developed.
Bluetooth in car production:
In car production, a lot of software is downloaded as the final step in the production line. This is an application that Bluetooth would be ideal for. The Bluetooth base station is connected to the production fieldbus. When the car connects online to the Bluetooth base station, it uploads its serial number. The production computer then loads the software for exactly this car via the fieldbus to the base station, which in turn transmits it to the car. However, this is a dedicated use and no Bluetooth devices other than those installed in the cars should be connected to the cell.
Bluetooth for car service:
A scenario for using Bluetooth could be:
1) When the car enters the gas station, its Bluetooth station contacts the gas station’s main computer. This has previously exchanged information with the car computer via the mobile phone system.
2) The main computer of the service station alerts the service man who has been assigned the task, and his PC makes contact with the car and downloads all the necessary information.
3) The service technician receives all the work instructions he needs on his PC. When maintaining the car, he can control and set several functions through the PC, such as: All lights, windows, air conditioning, engine parameters, etc. It can also download the latest software versions to any electronic control unit (ECU).
CAN/Bluetooth Basics:
CAN was developed as a basis for highly reliable communication over a twisted pair of wires, which can be applied from very simple tasks to advanced real-time control. To achieve this goal, it is based on the principle that each node in a system simultaneously examines each bit transmitted on the bus. This principle elegantly solves a number of problems such as bus access, collision detection, data consistency, etc. However, the condition that each node should see the same bit at the same time requires a controlled wave propagation time. This is easy to achieve in a wired system, but difficult to achieve in a wireless system. Therefore, all wireless transmissions in CAN systems must take place via gateways, and Bluetooth offers the best options for this task among the available radio standards.
The ideal Bluetooth concept for diagnostics:
The ideal Bluetooth concept for diagnostics should have the following properties:
1 Low cost
2 performance as required
3 standards as required
To achieve these goals we need a low cost, high performance Bluetooth unit that can be used for any application. Then it has to be stripped of everything that not everyone needs, so a concept like CAN. CAN provides the basic functionality required by any controller network, but the remaining required functionality must be provided by an additional higher-layer protocol. The base Bluetooth block should take care of the RF part and the essential part of the baseband protocol which is of little or no interest for any application but is essential for Bluetooth functionality.
Communication during production:
The wireless communication between the vehicle and the automation system of the production line could open up completely new functions in the production process. Depending on the process step, for example in final assembly, vehicle control and control of the production line can exchange status information about both the product and the process.
Communication during the service:
Possible uses in service can be easily derived from the scenario described above for the production process. Wireless communication between the vehicle and a service station computer may be used to exchange status information and service-specific information. This step can be supported by an upstream data exchange using telecommunications. Wireless communication in combination with a mobile service computer offers the service personnel optimal flexibility.
Advantages and Benefits:
The most important advantages of wireless technologies for technical tasks remain more or less hidden from the vehicle customer. The advantage of such a solution is the increase in flexibility, modularity and reliability. Although the benefit cannot be experienced directly by the customer, it is nevertheless important for the automotive industry. In addition, the potential of wireless communication at the level of technical tasks between intelligent devices and control units in the vehicle as well as control units and human-machine interfaces in the environment of the car can lead to new functionalities and an increase in flexibility in production and service. The advantage for the customer is an increase in reliability. The increase in flexibility is a great advantage for the product development phases. A simplified wiring harness and wireless interfaces are advantages for manufacturing. For service, maintenance and repair, wireless interfaces are advantageous with regard to the disassembly and assembly of parts. In addition, 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 ways to reduce product costs, for example through standardization and by reducing the assembly effort.
Conclusion:
There is a potential of up to hundreds of millions of Bluetooth nodes per year in the vehicle manufacturer market if Bluetooth can be used for real-time control and other technical tasks. A key trend in vehicle development over the past few years has been the increasing number of electrical and electronic systems. Many of these systems were introduced to offer customers innovations by increasing functionality, comfort and safety. Another reason is the partial replacement of mechanical components by electrical components or their integration into 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) Bluetooth wireless technology optimization
as an ideal interface for car diagnostics – Lars-Berno Fredriksson, Kvaser AB, Sweden