Modeling and simulation of Novel Electric/Hybrid Electric Multicopter Architectures for Urban Air Mobility

Abstract

This paper introduces a dynamic simulation environment developed for novel multi-copter aircraft architectures. The development is motivated by the need to better understand the safety implications of architectural design choices and to provide a formal reliability assessment framework for new Vertical Take-Off and Landing (VTOL) concepts able to consider various airframe and subsystems dynamic behavior. The concepts of interests are different multi-copters configurations investigated by NASA and featuring either electric, hybrid electric, or turboshaft driven powertrains. The simulation environment is a timemarching dynamic simulator formulated using physics-based subsystem models for the batteries, electric motors, turboshaft engines and electric generators. Identified fault modes are integrated into the subsystem models for subsequent use during reliability assessments. The impacts of subsystem faults are propagated to the vehicle flight dynamic response for analysis of their impact on the ability of the vehicle to sustain safe operations. Detailed features of the electric quadrotor model are provided to illustrate the simulation capabilities. Some faults are inserted on the different aircraft in hover and the subsystems behavior is successfully propagated at the vehicle level.

Improving the Dynamic Behavior of a Hybrid Electric Rotorcraft for Urban Air Mobility

“…This can be defined as an electronic device designed to act in the case of disturbing actions (pilot commands or wind gusts) that generate a difference between the engine required power and the engine actual power output and to adjust the torque split consequently. Since such deviation is mainly due to response lag of the engine (as explained in [27]), electric motors are used here to reach the equilibrium at the desired speed in a faster way. The action of the coordination block can be expressed as follows:…”

“…Energies 2022, 15, x FOR PEER REVIEW 7 of 21 sis of the effect of the PID parameters on the dynamic response of the system is reported in Section 4.3. As pointed out in [27], spool dynamics are critical for stationary and transient analysis because it captures the interactions among the power-consuming and producing gas turbine components on a spool. The typical value of the time constant for spool dynamics reported in the literature is about one second for turboshaft engines.…”

“…Heat transfer between a component's material and the flow going through the component during operation and tip clearance effects are neglected in this work, as also in [27].…”

“…The dynamic of a hybrid-electric multi-copter is analyzed by Bouchard et al [27] but for a series configuration where the rotors are mechanically connected to electric motors, and one of them is used as a master to regulate the angular velocity. The model was mainly developed to analyze the dynamic behavior of the system in the case of faults.…”