| Automating road vehicle control can increase the range and reliability of dynamic testing, which is currently limited by the use of human test drivers. Many tests specify precise steering or brake inputs which human drivers are only able to approximate, adding uncertainty to the test results.; The goal of this project is to develop a portable control system, or "Automated Test Driver" (ATD), to automate many test driving functions. Though controlling steering, brake, and throttle functions, the ATD will still allow a human to sit in the driver's seat if desired. The system is lightweight and compact enough to fit in the smallest passenger vehicle without substantially affecting its inertial properties, yet versatile enough to also control a large SUV. Test technicians can install the ATD in about an hour without permanent vehicle alteration, and later return the vehicle to stock condition for normal manual driving. Before testing begins, the ATD is paced through a brief tuning procedure to ensure stable and precise performance despite variation among test vehicles.; Though human test drivers are still the best choice for some types of tests, automation opens up a world of opportunity. As demonstrated by a variety of tests on three different vehicles, the ATD repeatably follows a predefined path with a given speed profile, or it can perform either path following or speed regulation independently. The ATD also precisely executes open-loop steering, throttle, or brake commands. It can automatically conduct tedious yet demanding tasks such as brake wear-in or understeer gradient tests, with greater accuracy than a human driver. Any event requiring precise timing or specific actuation displacements or velocities suits this system particularly well.; Key components for the Automated Test Driver have been designed by SEA Limited, Inc. This work explores the best means for integrating the SEA handwheel and brake and throttle actuators with a comprehensive control system. |
