Vehicle Speed Control by a Robotic Driver Considering Vehicle Dynamics for Continuously Variable Transmissions

Robotic drivers are used in vehicle performance tests, such as those for testing fuel consumption and exhaust gas. For driving test cycles, a test vehicle is driven on a dynamometer with a defined set of time and speed. These cycles have a tolerance band. Thus, to accurately compare the fuel consumption of various vehicles, it is necessary to run within the tolerance band and approach the target speed as close as possible by better control performance. However, because a vehicle has complex dynamic characteristics, it is difficult to improve the control performance especially in CVTs (continuously variable transmissions). In this paper, we improved the speed control performance through the derivation of a target speed waveform and design of a control system by considering the dynamic characteristics of CVT. First, we derived the target speed wave form that can remove the deviation from the tolerance band. Thereafter, we designed a control system to improve the speed control performance. The speed control performance of the proposed control systems were confirmed through vehicle running tests with the robotic driver.