d-CACC for Vehicle Platoons Lacking Acceleration Signal

Employing onboard sensors and vehicle-to-vehicle wireless communication, cooperative adaptive cruise control (CACC) allows vehicles in a platoon to follow their predecessors with accuracy, resulting in enhanced traffic flow, safety, and comfort. On the other hand, CACC is sensitive to wireless communication failure. In addressing the latter issue, this paper proposes a degraded CACC (d-CACC) that, in contrast with the CACC, does not require wireless communication, as so, it is not affected by communication failures. The proposed d-CACC is obtained by replacing the preceding vehicle acceleration in the CACC with an estimate obtained using backward derivative approximation. Resulting in a d-CACC since the host vehicles operate with degraded information compared to a traditional CACC system. The main advantages of the proposed d-CACC are the easy implementation, it does not require an extra algorithm for estimating the preceding vehicle acceleration; the error due to the acceleration estimative formula is taken into account in the control design mitigating unpredictable errors. Internal and string stability conditions are derived by frequency domain analysis methods. Then, in light of such stability conditions, an algorithm for the proposed d-CACC design is presented. The paper is concluded by showing simulated experiments that illustrate the effectiveness of the proposed d-CACC, considering also real-world implementation issues.