PARSEC: An Aerial Platform for Autonomous Deployment of Self-Anchoring Payloads on Natural Vertical Surfaces

PARSEC (Payload Anchoring Robotic System for the Exploration of Cliffs) is an autonomy-equipped aerial manipulator that can deploy self-anchoring payloads on rocky vertical surfaces. It consists of a hexacopter and a two Degrees of Freedom (2 DoF) mass balancing manipulator, which can autonomously deploy a self-anchoring payload from its custom end-effector. The payload anchors itself via an actuated microspine gripper. Payload sensor data is wirelessly transmitted to the primary vehicle during and after deployment. A novel state machine controls the four-stage PARSEC deployment process. First, the rotorcraft brings the payload into contact with the surface and applies a constant 6 N normal force through a feedback control loop to preload the payload microspine gripper. Second, while the rotorcraft maintains the constant normal force, the gripper is commanded to close until engagement with the surface is confirmed through the current feedback sensing. Then, the aerial manipulator pulls with 5 N force on the anchored payload to ensure a secure grip before releasing the package and flying away. We present experimental validation of a successful deployment of a 430 g payload on a vertical vesicular basalt surface.