Spin Stabilization of an Air Ambulance Litter

This paper proposes a new approach to stabilize the spin of a suspended litter during air ambulance rescue hoist operations. Complex forces generated by the helicopter’s downwash may cause a patient suspended in a rescue litter to spin violently. In severe cases, the spin destabilizes the suspended load, risks injury to the patient, and jeopardizes the safety of the aircrew. The presented design employs an anti-torque device to arrest the spin that is safer and faster than a tagline and is without the tactical constraints of the tagline. The device follows tailored control laws to accelerate a flywheel attached to the litter, thereby generating sufficient angular momentum to counteract the spin and stabilize the suspended litter. An inertial measurement unit (IMU) measures the position, angular velocity, and angular acceleration of the litter and delivers this information to a microcontroller. The research and prototype design were developed under the support of the U.S. Army 160th Special Operations Aviation Regiment (SOAR).

Design of a Payload Spin Stabilization System for an All-Rotating Aerial Vehicle

This paper details the electrical and mechanical design of a de-spin mechanism for the payload of an all-rotating aerial vehicle. The system is designed to be compatible with the Aeroseed aircraft developed by Aerospace Corporation. The system consists of a motor housing and a de-spun payload plate. The payload plate serves as a mounting surface for the desired de-spun payload, an IMU, an Arduino Nano, and a SD card module. The Arduino receives rotational velocity readings of the payload plate from the IMU and calculates the necessary spin rate to stabilize the rotation. This spin rate is sent through a slip ring to the motor and ESC enclosed within the motor housing, which implement the commands. The electronics on the payload plate are protected by a thin shroud that extends down from the motor housing. A slider mechanism with two degrees of translational freedom serves as the interface between the system and the aircraft and allows for the alignment of their respective centers of rotation. The final design has a total mass of 589.67 g and a height of 109.1 mm.

The Eu:CROPIS Mass Property Campaign: Trimming a Spin-Stabilized Compact Satellite for a Long-Term Artificial Gravity Experiment

Eu:CROPIS (Euglena Combined Regenerative Organic Food Production in Space) is the first mission of DLR’s compact satellite program. The launch of Eu:CROPIS took place on December 3rd in 2018 on-board the Falcon 9 SSO-A mission. The satellite’s primary payload Eu:CROPIS features a biological experiment in the context of closed loop coupled life support systems. The Eu:CROPIS satellite mission uses spin stabilization along its Z -axis to provide defined acceleration levels for the primary and secondary payloads to simulate either a Moon or Mars gravity environment. For the payload performance, it is vital to achieve a minimum deviation between spacecraft Z -axis and the major moment of inertia (MoI) axis to minimize the offset of the envisaged acceleration levels. Specific moment of inertia ratios between the spin- and minor axes had to be maintained to allow the attitude control system to keep the satellite at a stable rotation despite environmental disturbances. This paper presents the adaptive and flexible trimming strategy applied during the flight model production, as well as the mass property measurement acceptance campaign and the respective results.