An adaptive switched control approach to heterogeneous platooning with inter-vehicle communication losses

The advances in distributed inter-vehicle communication networks have stimulated a fruitful line of research in Cooperative Adaptive Cruise Control (CACC). In CACC, individual vehicles, grouped into platoons, must automatically adjust their own speed using on-board sensors and communication with the preceding vehicle so as to maintain a safe inter-vehicle distance. However, a crucial limitation of CACC is that the string stability of the platoon can be proven only when the vehicles have identical driveline dynamics and perfect engine performance (homogeneous platoon), and possibly an ideal communication channel. This work proposes a novel CACC strategy that overcomes the homogeneity assumption and that is able to adapt its action and achieve string stability even for uncertain heterogeneous platoons. Moreover, in order to handle the inevitable communication losses, we formulate an extended average dwell-time framework and an adaptive switched control strategy which activates an augmented CACC or an augmented Adaptive Cruise Control strategy depending on communication reliability. Stability is proven analytically and simulations are conducted to validate the theoretical analysis.Accepted Author ManuscriptTeam DeSchutte

An adaptive approach to cooperative longitudinal platooning of heterogeneous vehicles with communication losses

Despite the progresses in Cooperative Adaptive Cruise Control (CACC), a crucial limitation of the state-of-the-art of this control scheme is that the string stability of the platoon can be proven only when the vehicles in the platoon have identical driveline dynamics (homogeneous platoons). In this paper, we present a novel control strategy that overcomes the homogeneity assumption and that is able to adapt its action and achieve string stability even with uncertain heterogeneous platoons with unknown engine performance losses and inevitable communication losses. Considering a one-vehicle look-ahead topology, we propose an adaptive switched control strategy: the control objective is to switch from an augmented CACC to an augmented Adaptive Cruise Control strategy when communication is lost based on a dwell time characterized switching law. The simulation of the proposed control strategy is conducted to validate the theoretical analysis.Team DeSchutte

An adaptive approach to cooperative longitudinal platooning of heterogeneous vehicles with communication losses

Despite the progresses in Cooperative Adaptive Cruise Control (CACC), a crucial limitation of the state-of-the-art of this control scheme is that the string stability of the platoon can be proven only when the vehicles in the platoon have identical driveline dynamics (homogeneous platoons). In this paper, we present a novel control strategy that overcomes the homogeneity assumption and that is able to adapt its action and achieve string stability even with uncertain heterogeneous platoons with unknown engine performance losses and inevitable communication losses. Considering a one-vehicle look-ahead topology, we propose an adaptive switched control strategy: the control objective is to switch from an augmented CACC to an augmented Adaptive Cruise Control strategy when communication is lost based on a dwell time characterized switching law. The simulation of the proposed control strategy is conducted to validate the theoretical analysis.</p

Aneurysmal bone cyst of the spine: Report of four cases and review of the literature

Purpose: We report four cases of spinal Aneurysmal bone cyst (ABC) that were managed surgically at King Fahad Specialist Hospital in Dammam, Saudi Arabia. This report aims to describe the clinical features and the need for surgical excision preceded by embolization in spinal ABC. Method: A retrospective review of the OR list and tumor board records between 2013 and 2016 yielded a total of 4 cases of spinal ABC who were surgically treated at KFSH-D. Their clinical presentations, radiological and pathological features are reviewed along with the surgical intervention utilized and its outcome. Results: Total of 4 cases were identified, all of them were female (100%). The age ranged from 13 to 25 years old (mean age = 17.75). Two cases (50%) were located in the thoracic spine, one (25%) cervical and one (25%) in the lumbar spine. Back pain, unsteady gait, and progressive limb weakness were the most common presenting symptoms. All the cases underwent embolization followed by surgical excision and fixation with a variable degree of improvement postoperatively. Conclusion: Spinal ABC is a benign tumor that can present with a wide variety of non-specific symptoms. Pre-operative embolization can be helpful to reduce bleeding during surgery. Surgical decompression can lead to significant improvement even in case of severe neurological deficit. Radiation therapy can be used as an adjunct treatment in selected cases