星球车运行于松软星球表面时，易发生滑转和滑移。在下坡或制动等情况下，车轮实际前进速度大于理论前进速度，车轮将处于滑移状态。目前的研究主要针对滑转力学，而针对滑移力学的研究较少，滑移分为纵向滑移和侧向滑移。用试验的方法研究与星球车相关的多种因素对星球车车轮纵向滑移试验结果的影响。在车轮性能测试台上安装不同构型的车轮，研究车轮半径、轮刺个数、前进速度和垂直载荷对车轮纵向滑移力学特性的影响规律。纵向滑移试验结果表明，前进速度的增加对沉陷量和轮地作用力/力矩的影响较小；电动机输出力矩绝对值随车轮半径的增加而增加；前进阻力绝对值随垂直载荷的增加而增加；前进阻力系数随滑移率的增加而增加，车轮下的坡度角越大，需要的前进阻力系数越大；电动机输出力矩在滑移率从0增加到0.2时的变化速率，远大于其在滑移率从0.2增加到0.6时的变化速率。

Wheels will slip or skid when planetary exploration rovers traversing on soft deformable terrain. Wheel’s real forward velocity is larger than its theoretical forward velocity when planetary rovers brake or move down a slope, and wheel will be in skid. Skid covers longitudinal skid and lateral skid. Recent literatures most focus on wheel-soil interaction in slip, but skid mechanics has rarely been carried out. The influences of many factors related to planetary exploration rovers on longitudinal skid experimental results were studied using experiments. Install wheels with different configuration to wheel performace test−bed to study the influences of wheel radius, lug number, forward velocity and vertical load. Experimental results show that：The increasing of forward velocity has small influence on wheel sinkage, forward resistance force and electromotor output torque; Absolute values of electromotor output torque increase with the increasing of wheel radius; Absolute values of forward resistance force increase with the increasing of vertical load; Resistance force coefficient increases with the increasing of skid ratio and larger downhill angle needs larger skid ratio; The change rate of electromotor output torque when skid ratio ranges from 0 to 0.2 is bigger than that when skid ratio ranges from 0.2 to 0.6.