A device configured to couple to a wheel assembly of a mobile device is provided. The device includes a first side portion configured to couple to a first lateral side of the wheel assembly. The device also includes a second side portion configured to couple to a second lateral side of the wheel assembly opposite the first lateral side, wherein the first and second side portions are compliant mechanisms configured to both move a movable obstacle out of a path of the mobile device and to retract in response to a force exerted on the first and second side portions by a fixed obstacle disposed along the path.