Using LabVIEW Real-Time and PXI to Enhance a Volvo Car Corporation Student Project

Author(s):
Holger Andersson - Luleå University of Technology

Industry:
Automotive, University/Education, Transportation

Products:
PXI/CompactPCI, LabVIEW

The Challenge:
Developing a control system that incorporates continuous changes of several parameters.

The Solution:
Using LabVIEW Real-Time in a PXI chassis with embedded controllers to implement a drive-by-wire system in a production car and improving the performance of the system during test driving in a real-time environment without delay or malfunction.

Virtual Pedals
The project, “virtual pedals,” was a global project in which students from Luleå University of Technology and Stanford University, USA, worked together with Volvo Car Corporation to develop new concepts for safer brake and accelerator pedals. The traditional design, with mechanical linkages, can cause injury to the driver’s feet and lower leg in the event of a crash.

Fulfilling Redundancy Requirements
Since the system would replace the ordinary brake and accelerator system in a working car, we had to achieve some redundancy. The VOLVO S80 already has an electronically controlled accelerator system. Two separate signal circuits manage its redundancy-one analogue signal and a digital PWM signal. The engine PU system compares these signals and they cannot differ more than two percent before it shuts down the servo unit in the throttle valve system.

We replaced the brake pedal system with a DC engine controlled linear motion unit. To manage the high current in the DC engine we used a servo amplifier. Both of these systems require an extremely fast and reliably test console.

Speed, Flexibility, Reliability
We chose National Instruments products for the application based on their speed, flexibility, and reliability.

The PXI chassis is the 1000B with DC power supply and the I/O unit is the NI PXI-6052E (333 kS/s) analog multifunction data acquisition card. The heart of the system is the NI PXI-8176 RT embedded controller with an Intel Pentium III processor. The controller communicates across a standard Ethernet with a Windows laptop, running the LabVIEW Real-Time module.

With the use of National Instruments equipment, the implementation in the car was no problem. We easily fit the robust PXI chassis and the rest of the apparatus in the trunk of the car. For easy access of the driving parameters, we did mount the laptop with the control panel of the system in the driving environment.
We used the LabVIEW Real-Time, which provided us with several advantages:

• It runs on its own real-time operating system, which gives extremely good stability and reliability
• The speed is outstanding because of its own operating system
• You can modify and adjust control parameters during test driving and evaluation
• You can easily add CAN-bus system for communication with the vehicle’s onboard computer
  
  

Another benefit with of system is that it gave us the opportunity to try out and implement different subsystems, such as hill holding, which makes parking and starting in hills much easier for the driver without difficult and time-consuming programming.

The NI Advantage
Using National Instruments products in this project, we created a system that we could evaluate and test a modern production car without loss of performance and reliability. This complex interface would prove an arduous and very cost-demanding task to design and produce for ordinary micro processing units to be developed and programmed. It also gave the university a great tool to use in future projects with the automotive industry because of its ease of adaptability and user-friendly interface.

For more information about this project, contact:
Holger Andersson
Korngatan 3
943 31 Öjebyn
Sweden
E-Mail: ho.andersson@telia.com
Tel: +46 70 331 88 84

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