Development and error estimation of centroid measurement system for planet rover

In order to realize low gravity compensation experiment of a overhung planet rover and understand the centroid variation of the planet rover in different working conditions, a planet rover centroid measurement system was designed. The system can measure the centroid position of the planet rover under different working conditions by one on-line measurement and one auxiliary measurement. Firstly, a centroid measurement system for planet rover was developed, which was mainly composed of six sets of height-adjustable and joint arm type electronic scale measuring unit. Combined lifting method with tilting-platform method, the rover centroid was calculated by measuring the pressure of every wheel in different operating conditions with every electronic scale. Secondly, the measuring steps and methods of the system were described. The calculation model of centroid position vector and its coordinate components were derived based on the measurement of every wheel pressure. Thirdly, the error of the measurement system was analyzed, including systematic error, random error and accidental error, and the measures to eliminate or reduce the errors were proposed. Moreover, the systematic errors caused by sensor measurements were quantitatively analyzed. The results show that the maximum measurement error in each direction is 0.694, 0.163 and 0.255 mm respectively, and the overall error is less than 0.757 mm. The proposed system can meet the planet rover center of mass measurement accuracy requirements in different working conditions.