| Popis: |
A robotic "drive-cycle controller" has been developed for controlling automatic and manual-gear-change passenger vehicles during tests on roller dynamometers. The controller comprises a five-channel electro-hydraulic actuator system located in an adjustable supporting frame, controlled from a dedicated micro-computer. The actuator/frame assembly can be fitted to the vehicle by a single operator without removal of the seats or modification to the vehicle. Two actuators operate the gear lever, with one actuator operating each of the three foot pedals. The computer uses pre-taught gear-lever and foot-pedal positions to control gear-change sequences and maintain a speed-time profile. Deceleration is controlled by actuation of the brake pedal, as required, to a specified brake-pedal load. Actuator overload, engine overspeed, actuator-displacement error, and sequence checks are embodied in the program to provide a failure alarm in the event of malfunction. Comparison of speed and manifold depression measurements obtained from tests with the US Federal urban driving schedule, for both the drive-cycle controller and a human driver, indicates that overall repeatability with the controller was improved by about 70 per cent with respect to speed control, and 30 per cent in terms of variation of manifold depression. The controller was also seen to give good reproduction of the required driving schedule. (Author/TRRL) |
