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 rotorcraft 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. The payload sensor data is transmitted to the the primary vehicle during and after deployment through a wireless connection. A novel state machine controls the four-stage cooperative PARSEC deployment process. First, the rotorcraft brings payload into contact with surface and applies a constant 6 N normal force to it through a feedback control loop to engage and preload the payload gripper. Second, the payload uses current feedback to detect gripper engagement with the surface, while the rotorcraft maintains the constant normal force. Then, the aerial manipulator pulls with 5 N force on the anchored payload to ensure a secure grip before the final stage of releasing the package and flying away. We present experimental validation of a successful deployment of a 430g payload on a vertical vesicular basalt surface.