3 research outputs found
Versatile Multilinked Aerial Robot with Tilting Propellers: Design, Modeling, Control and State Estimation for Autonomous Flight and Manipulation
Multilinked aerial robot is one of the state-of-the-art works in aerial
robotics, which demonstrates the deformability benefiting both maneuvering and
manipulation. However, the performance in outdoor physical world has not yet
been evaluated because of the weakness in the controllability and the lack of
the state estimation for autonomous flight. Thus we adopt tilting propellers to
enhance the controllability. The related design, modeling and control method
are developed in this work to enable the stable hovering and deformation.
Furthermore, the state estimation which involves the time synchronization
between sensors and the multilinked kinematics is also presented in this work
to enable the fully autonomous flight in the outdoor environment. Various
autonomous outdoor experiments, including the fast maneuvering for interception
with target, object grasping for delivery, and blanket manipulation for
firefighting are performed to evaluate the feasibility and versatility of the
proposed robot platform. To the best of our knowledge, this is the first study
for the multilinked aerial robot to achieve the fully autonomous flight and the
manipulation task in outdoor environment. We also applied our platform in all
challenges of the 2020 Mohammed Bin Zayed International Robotics Competition,
and ranked third place in Challenge 1 and sixth place in Challenge 3
internationally, demonstrating the reliable flight performance in the fields
Calcium sparks enhance the tissue fluidity within epithelial layers and promote apical extrusion of transformed cells
In vertebrates, newly emerging transformed cells are often apically extruded from epithelial layers through cell competition with surrounding normal epithelial cells. However, the underlying molecular mechanism remains elusive. Here, using phospho-SILAC screening, we show that phosphorylation of AHNAK2 is elevated in normal cells neighboring RasV12 cells soon after the induction of RasV12 expression, which is mediated by calcium-dependent protein kinase C. In addition, transient upsurges of intracellular calcium, which we call calcium sparks, frequently occur in normal cells neighboring RasV12 cells, which are mediated by mechanosensitive calcium channel TRPC1 upon membrane stretching. Calcium sparks then enhance cell movements of both normal and RasV12 cells through phosphorylation of AHNAK2 and promote apical extrusion. Moreover, comparable calcium sparks positively regulate apical extrusion of RasV12-transformed cells in zebrafish larvae as well. Hence, calcium sparks play a crucial role in the elimination of transformed cells at the early phase of cell competition