A Study on the Energy Efficiency of an Autonomous Rover

Context. Autonomous vehicles have become commonly used in various industries. Energy consumption is influenced by a complex combination of hardware, software, and control-level decisions. Goal. This study aims to empirically assess and improve the current energy consumption patterns of an autonomous rover, under different operational conditions. Method. A controlled experiment is conducted using the ASE/Rover, a battery-powered autonomous vehicle built at Vrije Universiteit Amsterdam to perform in racing competitions. Three CPU governors (ondemand, powersave and conservative) and imaging resolutions (640x480, 352x288 and 160x120) are tested, in different scenarios: idle, imaging and driving. Power, energy, CPU temperature, and battery voltage data are collected at high sampling rates. These metrics are analyzed to assess energy savings, thermal stress and data variability. Results. The powersave governor significantly reduces mean energy consumption, mean power, and CPU temperature, compared to the baseline ondemand and conservative governors. However, powersave introduces greater variability and less consistent measures, likely due to its fixed low-frequency behaviour. Imaging resolution is also a strong driver of energy consumption. The final driving experiment comparing the baseline with the powersave governor using the 352x288 resolution saved 12.19% of energy, providing evidence of the effectiveness of the interventions. Conclusions. Targeted, low-complexity interventions can significantly reduce energy consumption of an autonomous vehicle without compromising its functional performance. The lessons learned presented in this study can guide future energy measurements in embedded and autonomous platforms.