The Simple (Non-Adaptive) Cruise-Control Testbed

The current version of a simple cruise control system (CCS) testbed is described on this page.

Why a "simple" testbed?

With the widespread adoption of embedded systems, it has become increasingly common to use Hardware-in-the-Loop (HIL) techniques to evaluate and compare design solutions. We have recently described a detailed an HIL simulation of an adaptive cruise-control system (ACCS) for a passenger car (see links below).The ACCS simulation provides accurate results but is too complex for some purposes.  We have therefore developed a simple (non-adaptive) cruise-control system (CCS) testbed.

CCS description

An automotive CCS is a system that takes over the control of the throttle, in order to maintain the vehicle at the desired set speed. Such a driver assistance system can reduce the strain on the driver especially while travelling on long journeys.

Such a CCS will typically have the following features:

1. An ON / OFF button to enable / disable the system.

2. An interface through which the driver can change the set speed while cruising.

3. Switches on the accelerator and brake pedals that can be used to disengage the CCS and return control to the driver.

For the purpose of our study, the specification of the CCS was simplified such that the vehicle was assumed to be always in “cruise” mode. While in cruise mode, a “speed dial” was available to allow the driver to dynamically change the car speed. The control process ensures that the vehicle would travel at the desired set speed.

The car environment model

The car environment model was implemented using a time-triggered co-operative scheduling architecture on a desktop PC. The implementation was carried out on a basic desktop PC (Intel Pentium II 300 MHz processor). In order to access the PC hardware level, an operating system (OS) was required. DOS (Disk Operating System) was chosen because it offers the required flexibility at low cost.  The complete source code for the car environment model is available (see downloads below).

The control system

To control the velocity of the car at a set speed, a PID algorithm was used.  The implementation was carried out on a C167 embedded Infineon microcontroller.  Two different implementation options were used: a single node (Figure 1) and a dual-node (Figure 2) implementation.  The complete source code for those implementation options are available (see downloads below).

Figure 1 - Single-node CCS

Figure 2 - Dual-node CCS

Acknowledgements

The version of the cruise-control system described here was developed by Devaraj Ayavoo as part of his PhD project in the ESL.  Devaraj's PhD supervisors are Michael J. Pont (ESL) and Stephen Parker (Pi Technology).

Links

A more detailed version of the CCS with adaptive control is available here:

Adaptive Cruise-Control System (ACCS) testbed

Do I need a licence?

The simple cruise-control system and related programs and documentation may be used without charge for commercial and non-commercial use as long as the author and disclaimer notices are maintained. 

What number should I call to get support?

Sorry - you're on your own (we cannot provide support).

I've found a bug!

If you find a bug, please send Devaraj Ayavoo an e-mail (contact details below).

Disclaimer

The simple cruise-control system is solely intended for use in university teaching and research projects. 

All of this material is provided "as is" and any express or implied warranties, including, but not limited to, the implied warranties of merchantability and fitness for a particular purpose are disclaimed. In no event shall the author or contributors be liable for any direct, indirect, incidental, special, exemplary, or consequential damages (including, but not limited to, procurement of substitute goods or services; loss of use, data, or profits; or business interruption) however caused and on any theory of liability, whether in contract, strict liability, or tort (including negligence or otherwise) arising in any way out of the use of this software, even if advised of the possibility of such damage.

Downloads

NOTE: By downloading, you signify that you accept the disclaimer (above).

• Car environment mode (62 KB): Car_Environment_Model.zip

• Single-node CCS implementation (125 KB): Single_node_CCS.zip

• Dual-node CCS implementation (287 KB): Dual_node_CCS.zip

Contact details

Mr. Devaraj Ayavoo (da18_at_le.ac.uk)

Author: S A Key, last updated 16/11/2004. Best viewed on 1024 x 768.
This document has been approved by the Head of Department.
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