Fig. 2From: Estimation of resistance force at steady-state sinkage for cylindrical wheel-typed lunar/planetary exploration rovers with function of push–pull locomotionActual image of the traveling experiment on the soil. The rover firstly shrinks its wheel-base, and the front wheel is fixed to the ground and supports the rear wheels’ motion (a–b). Next, the rover extends its wheel-base, and the rear wheel is also fixed to the ground and supports the front wheels’ motion (b–c)Back to article page