F1 racing car corner angle gauge and brake dynamometer based on virtual instrument

Application areas:

car

challenge:

Building a completely new dynamometer that can handle the high speed and acceleration levels of a Formula 1 car and completing these tests on an actual wheel and suspension assembly.

Application solutions:

The new system will be based on an industrial Pentium 4 HT 3.2g Hz, 1GB memory computer, using NI data acquisition and control card, the software is compiled through the LabVIEW graphical programming environment to achieve.

Products used:

Data Acquisition (DAQ), Dynamic Control, PXI/CompactPCI

AP Racing has been a world leader in brake caliper and racing clutch technology and production for over 30 years. In the process of continuously surpassing existing products, AP Racing came to the conclusion that if a new dynamometer has the following capabilities, it will have a very clear advantage:

* It is possible to test brakes and calipers during equipment installation and during actual wheel and suspension assembly.

* It has enough power to accurately simulate the speed and acceleration of a Formula 1 car.

*It simulates the air flow around the brake caliper and can study the air flow through different duct designs.

* It can import tracking data of braking and acceleration.

As AP Racing has very strong design capabilities, they decided to build the equipment in-house, which would be beneficial to reduce costs and better control system performance. For the software and electronic control system, AP Racing chose the Computer Control Solution (CCS) we developed based on our experience in this field and a series of test machines we had previously successfully used for AP Racing maintenance.

The system is based on an industrial PC with a Pentium 4 HT 3.2 Hz, 1 GB RAM and the following acquisition cards:

*PCI-DIO-96 provides 96-bit input and output

*PCI-6033E provides 8-bit and 64-bit analog input

*PCI-7344 four-axis controller

We connect these boards through various signal conditioning devices to control and measure the following system links

*288 kW converter

*240 kph inflow air flow control

*Hydraulic servo control system for brake pressure application

*Measurements of torque, temperature, infrared temperature, pressure and speed

*Transducers used to control mechanical planes

*Water cooling and monitoring

* Cooling and monitoring

*Disk mounted capacitors and replacement[page]

We wrote the software entirely in the LabVIEW graphical programming environment. The main design elements are as follows:

* Intuitive: We have integrated the design process functions into the main menu so that the operator can find all inputs and outputs, set up tests, run tests, and analyze data. There is also a simplified menu option that turns this interface into a basic form for running pre-design tests.

*Calibration Screen: Taking full advantage of the dual TFT displays, we designed the calibration screen to provide a tabular display of all inputs and outputs on the left screen. These tables are perfect for the calibration engineer to view and check the inputs and outputs. The right screen includes a complete plant simulation diagram, which is very useful for identifying the location of the inverter and controller.

* Modularization for easy test development: We break down each aspect of a test into modules (e.g., apply brakes, go to speed, loop, capture start and stop). Users can build an entire test suite by adding these modules to a simple list.

* Intuitive Run Screen: Taking advantage of the speed of LabVIEW, we were able to display the entire run screen, marking the location of the test, simulation diagram, dual page display and status information.

Use the latest version of LabVIEW and NI-DAQmx to control

During the final system development process, NI released LabVIEW 7.1 and NI-DAQmx. After researching the software, we decided to upgrade to the latest version of the system because it provides several important advantages, as follows:

*Smooth and convenient LabVIEW version upgrade: Before the product was released, we assisted in the debugging of the beta version, which gave us initial confidence in the product. We also found that the newly released product was very stable and easier to upgrade.

* High-speed data acquisition: The system was designed with the ability to continuously save and display simulation graphs and charts, which were displayed on two screens, with data changing at a rate of 2 kHz per channel. Through the implementation of the NI-DAQmx code, we saw an increase in data acquisition rates by about 5 times, thus freeing up the system to run more real-time control and display.

* Nonlinear Acquisition: Using NI-DAQmx, we automatically applied a set of nonlinear acquisitions to the infrared temperature transducer, thus avoiding post-processing and displaying these linearized channels in real time.

*Installation screen implementation: We used a newly implemented installation screen that shows the status of each specific point in the test on the installation screen on the main run screen. One advantage we experienced was that the main screen was always in focus, so when we were running the installation screen, the abort button was always active.

Design Challenge: High-Speed ​​Independent Closed-Loop Control

The system requires the following closed-loop control:

* Torque Control: Controls the applied brake torque to match actual conditions, general and speed dependent levels.

* Pressure Control: Controls the pressure applied to the brakes to match actual conditions, general and speed dependent levels.

* Simulate air flow in ducts and brake-based velocity output

*Speed ​​control: motorized reverser control

There are a variety of servo control cards that are similar or DSP solutions for this application. However, we found the NI 4-axis motion controller to be the perfect fit for this system for the following reasons:

* It is fully controlled within the LabVIEW environment: This is very important from a software maintenance perspective because it avoids the version control issues and extra installations that come with coexisting with other software products and associated code libraries.

* Low cost: Compared with other DSP implementations or servo controllers, the price/performance ratio is unmatched.

* It has a high PID loop rate: The PID loop rate of up to 16 kHz ensures that the PID control consists of some macro commands, which is easier to control than some general controllers, thus providing very smooth mechanical activities and control.