In this paper, non-linear estimators and feed-forward actions are designed to solve a vehicular platoon control problem. In particular, these estimators are useful in implementation of a Multi-Layer Consensus Seeking approach to the platooning problem. In the Multi-Layer approach the feed-forward part is built separately from the feedback part, based on desired trajectories. This opens the way to study different methods to compute this information. In this work, sliding mode algorithms are employed to generate the desired trajectories and also to compute the feed-forward control input of each vehicle. In this way, a velocity-dependent inter-vehicle spacing policy can be realized without using derivatives of the vehicular acceleration to compute the feed-forward input. Furthermore, a full-state feedback implementation scheme is discussed. The vehicles are modeled with heterogeneous linear longitudinal dynamics. The proposed algorithms are validated through experiments on automated cars.