This thesis is on the assessment of handling qualities for a robust controller, previously designed using H∞ techniques for a longitudinal model of the Bo-105. A piloted simulator flight test was conducted in which a set of tasks was flown. These tasks included configuration of stick sensitivity, pitch and altitude tracking tasks, flown at different flight conditions to show robustness, as well as a bob-up and acceleration-deceleration task. The resulting handling quality rating showed that the controller, designed for a theoretical rating of level 1, achieved between level 1 and level 2 handling qualities between the tasks. Non-controller factors, such as stick force, missing cueing and performance limits, were commented on by the pilots to have an effect on the rating. Anti-windup methods, clamping and back-calculation, were used to improve controller response, and reduce oscillations observed during testing.

Urban air mobility (UAM) is an emerging innovation and research area and is one of the key pillars enabling
future vertical mobility. UAM specifically focuses on air travel within and around urban areas. In recent years, more studies have been performed on the acceptability and performance of UAM vehicles. However, a research gap is present on the dynamic rollover tendencies for UAM lift plus cruise vehicles, a type of Vertical Take-Off and Landing (VTOL) multirotor vehicle. Dynamic rollovers are known to be a risk for helicopters, another type of VTOL. A dynamic rollover occurs when the center of gravity of an aircraft rotates around a pivot point. The pivot point is the contact point of the surface and the aircraft’s landing gear. This causes the aircraft to roll and eventually crash. There are multiple situations in which a rotary aircraft can roll over, such as sloped landings or due to strong crosswinds.

This thesis research aims to investigate the susceptibility of dynamic rollover for a lift plus cruise vehicle during landing through computational simulations. Investigating this susceptibility is achieved by identifying the flight conditions that influence the dynamic rollover behaviour of the vehicle and testing design alterations to the lift plus cruise model. To model the rollover susceptibility, a base scenario is introduced in which an eight-rotor lift plus cruise vehicle makes a vertical landing of eight meters and reaches a landing surface. During this descent, the vehicle encounters a wind gust. The model was developed using the equations of motion with five degrees of freedom, which include: roll, pitch, surge, sway and heave.

From this research it can be concluded that the wind gust influences the rollover susceptibility of the vehicle. The stronger the wind gust, the more prone the vehicle is to roll over and the more time the wind gust has to develop, the less chance the vehicle has to roll over. In comparison to the helicopter, the multirotor is more stable and less prone to rolling over. Design alterations have been applied to the model to investigate whether improvements are possible in the design of the lift plus cruise vehicle to decrease its tendency to roll over. It was found that a smaller disc loading is beneficial, as well as a smaller lateral distance between the rotors. To reduce the wingspan of the vehicle and therefore, reduce the angle at which the rotor can touch the ground. When investigating a reduction in the number of rotors, in all cases, a reduction would not benefit the susceptibility to rollover in a positive sense. The influence of the landing gear structure is small, therefore, the development of a new type of landing gear does not have a priority.

In conclusion, this thesis explores the factors influencing rollover susceptibility in a UAM multirotor vehicle. By systematically analysing the dynamics of vehicle behaviour under various conditions, key insights into rollovers were uncovered.

Accurate yield estimations are necessary to prove the financial viability of wind farms in early-phase design. Due to the long time period between sea bed lease auctions and the decommissioning of wind farms, uncertainties in wind farm properties and atmospheric conditions arise. Wake steering is a wind farm flow control technology that was shown to have a substantial impact on annual energy production (AEP) in many field experiments; however, the accuracy of the AEP uplift estimated during the uncertain, early design phase is unknown. The present article addresses this concern by propagating uncertainties in atmospheric conditions, - namely turbulence intensity, wind shear and air density - wind rose and thrust curve forward to quantify the statistical uncertainty in AEP uplift estimations and by performing a sensitivity analysis to rank the significance of these uncertainties. For the Offshore Windpark Egmond aan Zee (OWEZ), the 95% confidence interval for the GCH is between 0.88% and 0.93%, while for the CC model this is between 1.08% and 1.14%. When compared with the deterministic AEP uplift of 0.97% for the GCH and 1.16% for the CC respectively, it is concluded that there is benefit from wake steering under input uncertainty for the OWEZ wind farm. Finally, for this case study the main driver of the variation in AEP uplift is the wind rose, with the other parameters having negligible effects.

Tiltrotor aircraft combine the vertical takeoff and landing capabilities of helicopters with the speed and range of fixed-wing airplanes. Modeling their transitional flight dynamics, particularly the role of rotor flapping, remains a challenge. This paper develops an analytical framework that incorporates first-order rotor flapping and nacelle tilt dynamics into tiltrotor simulations. Using small-angle assumptions and blade element theory, the model captures the coupling between rotor flapping and body angular rates across different nacelle tilt angles. Results indicate that the influence of flapping dynamics is more noticeable in configurations closer to helicopter mode, particularly within 30 degrees of nacelle tilt from this regime. In these conditions, the rotor blades experience higher effective angles of attack, amplifying rotor-induced moments. As the nacelle tilts toward airplane mode, the incoming airflow approaches more from above the rotor plane, reducing the blades’ effective angle of attack and, consequently, their contribution to flapping dynamics. The study also highlights that nacelle tilt rates introduce gyroscopic precession and transient moments, which are more pronounced during fast transitions or asymmetric maneuvers. While heavier tiltrotors like the XV-15 show limited sensitivity to flapping dynamics in airplane mode, trends in lower-speed and rotor-dominated conditions emphasize the need for accurate modeling of flapping effects. This is especially relevant for lightweight tiltrotors and urban air mobility vehicles, where reduced inertia amplifies rotor-induced responses. These findings suggest that including flapping and nacelle tilt dynamics in flight dynamics models can improve predictions of handling qualities, particularly during transitions between flight modes.

Since the 1970s, helicopters have been vital in disaster response but face limitations in cost, infrastructure, and
maneuverability. This thesis presents the design and optimization of an emergency response flyer tailored for the
GoAERO competition. Multirotor configurations with hybrid-electric propulsion are investigated to overcome
the limitations of existing fully electric VTOL technologies.

A Multidisciplinary Design Optimization (MDO) framework is applied to hybrid-electric quadrotor, hexarotor,
and octorotor configurations, optimizing the balance between rotor count, mass, and performance. The objec-
tive is to minimize Maximum Takeoff Mass (MTOM) while enhancing dynamic performance and maximizing
the payload-to-system mass ratio. This study addresses a key research gap by integrating early-stage handling
qualities (HQ) evaluation and exploring trade-offs between optimized rotor count configurations. Aerodynamic
forces and energy consumption are estimated using momentum theory, while system dynamics are analyzed
through Newton-Euler equations and eigenvalue assessments.

Results show that the hexarotor configuration achieves the fastest convergence, balancing design complexity and
design space exploring. Configurations maintain a disk loading between 43–63[kg/m2] with hover efficiency
between 5 and 5.8. A higher rotor count improves hover efficiency and disk loading, making performance com-
parable to eHang and Vahana while achieving nearly twice the cruise speed, rivaling helicopters.

At a hybridization factor (HF) of 0.1, MTOM is reduced by 75%, with only a 3% mass variation between con-
figurations. However, at higher HF, mass increases by 20% due to relatively low energy density of batteries
further impacting structural support demands, underscoring the need for a more detailed support structure model.
Stability analysis confirms neutral hover stability, while a real, negative eigenvalue at cruise identifies the surge
subsidence mode, governed by system mass.

Rotor count significantly impacts design flexibility. Hexacopters and octocopters offer better disk loading homo-
geneity, whereas quadrotors face constrained rotor sizing and elevated blade and disk loading, limiting efficiency.
Quadrotors excel in payload-to-mass ratio and simplicity, making them ideal for productivity missions but less
suited for maneuvering-intensive tasks with lower disk loading and control authority, highlighting the importance
of early HQ considerations.

This thesis makes a valuable contribution to the advancement of eVTOL research by addressing early-stage HQ
assessments where on the basis of other literature and configuration optimization, the hexacopter emerges as the
most viable for the GoAERO competition, striking the best balance between mass, handling qualities, and mission
performance.

One of the biggest trade-offs in aviation is between a vehicle’s ability to take-off and land vertically and its efficiency in cruising flight. The recent drive for electric vehicles creates space to consider new solutions to this trade-off. Tilt wing aircraft offer significant advantages in vertical take-off and landing (VTOL) operations due to their versatile design. One of the difficulties in designing configurations with little historical data is that they are difficult to predict. The challenge of formulating a flight dynamics model valid through the transition phase from vertical to horizontal flight is undertaken in this study. This research aims to investigate the tilt wing aircraft behaviour through the wing tilt transition, as well as the stability characteristics. A six degree of freedom model implemented on the Canadair CL-84 Dynavert compares favourably to flight test data, albeit with low-fidelity especially around hovering flight. The likely cause is the simple rotor to wing slipstream interference modelled. The stability characteristics reveal large spikes in positive stability of the longitudinal derivative Cmu and Cmw due to the behaviour of the wings and the slipstream effect on the horizontal tail, with normalized values up to 5.5 and 150 respectively. Some unstable flight configurations are found within the flight envelope at 41 degrees and 28 degrees due to wing stall.

This research focuses on developing a control system for a compound coaxial helicopter (CCH) similar to the SB-1 Defiant, capable of both hovering and high-speed forward flight. The study introduces a 9 degrees of freedom mathematical model with 3 inflow states for the upper rotor, lower rotor, and pusher propeller, accounting for mutual rotor interference. The model undergoes a trim and stability analysis, revealing instability during transitional flight, necessitating a stability and control augmentation system. This system is implemented using an Explicit Model-Following (EMF) method, stabilized by a PID controller and a Weighted Pseudo-Inverse (WPI) control allocation algorithm. The controller effectively manages various flight controls through transition, as tested in a bob-up/bob-down mission task. While it performs well, there is room for improvement in input coupling and jitter behavior. Finally, an objective handling quality assessment based on ADS-33E metrics shows that the control system meets Level 1 handling quality criteria in the transition region for attitude and bandwidth, though some inefficiencies in control allocation during large attitude maneuvers were identified.

This research investigates the impact of modeling uncertainties on helicopter handling qualities and simulator tolerances as prescribed by ADS-33 and JAR-STD. Using a six-degree-of freedom linearized model of the Bo105 helicopter, the analysis focuses on the propagation of stability derivative uncertainty on four Quantities of Interest (QoIs): Pitch Quickness, Roll Quickness, Pitch-Due-To-Roll Cross-Coupling, and Roll-Due-To-Pitch Cross-Coupling. These QoIs are evaluated across the flight envelope, from hover to maximum velocity (145 knots), capturing sensitivity variations with flight con ditions and advance ratios. To propagate uncertainty, two methods are employed: Monte Carlo Simulation (MCS) and Polynomial Chaos Expansion (PCE), with PCE reducing computation time by 98% while maintaining accuracy. Each QoI shows greater sensitivity to uncertainty at the extremes of the flight envelope. Pitch Quickness is most sensitive at high speed, whereas the other QoIs are most sensitive at hover. Cases
with both JAR-STD tolerance violations and ADS-33 HQR level changes show JAR-STD tolerances are generally more stringent, except for the Cross-Coupling QoIs, where ADS-33 level changes are more frequent.

With a booming eVTOL market, many new companies will design their own vision of the future of urban transport. Therefore, a MATLAB flight dynamics model is needed to accurately design a Lift + Cruise Aircraft in the preliminary design phase. The MATLAB program is based on the EVE V3 aircraft by Embraer. The model successfully simulates an input flightpath and is highly customizable, providing preliminary design engineers with flexibility to modify and enhance the eVTOL aircraft. The program optimizes the input aircraft, accommodating up to 12 upward facing engines, 6 forward engines, 2 wings, and 2 stabilizers. The simulation-based approach reduces the need for physical prototyping and testing, offering a cost-effective tool for early-stage eVTOL aircraft development. Overall, this flight dynamics simulation proves instrumental in the preliminary design of Lift + Cruise eVTOL aircraft, providing engineers and designers with an indispensable asset for developing efficient, safe, and high-performance eVTOL technology.

This research presents a comprehensive modeling approach for the flight dynamics of a hybrid compound helicopter, employing classical mechanics methods. The derived non-linear mathematical model encompasses the individual components of the aircraft, including the rotor, propellers, wings, fuselage, and empennage, which are then integrated into a unified dynamics framework through the final Equations of Motion. Notably, the model incorporates a conventional first-order steady flapping motion and quasi-dynamic inflow modeling for both the rotor and propellers. The resulting model represents a complete 9 Degree-of-Freedom system, augmented with 6 mechanical ones and an additional 3 for the inflows of the rotor and the two propellers. As an over-actuated coupled system, it offers 7 available controls; rotor collective pitch, rotor longitudinal and lateral cyclic pitch, port-side and starboard-side propeller pitch, elevator deflection, and rudder deflection. The primary objective of this study is to identify operating trim points during forward flight, ranging from hover to the observed maximum airspeed of 255 knots. Achieving trim through numerical optimization involves a control allocation process utilizing a mapping function that prioritizes the auxiliary propulsion. The research findings demonstrate the successful implementation of a slowed-rotor strategy at high speeds, effectively mitigating compressibility effects, and a linearized mathematical system is derived, providing essential insights for future stability analysis and control system design. These outcomes contribute valuable information toward the advancement of hybrid compound helicopter technology.

Control of a helicopter with a deployed dipping sound navigation and ranging (SONAR) is no trivial task due to the complex dynamics of the suspension cable. The cable can change shape, which influences the effect of water, wind and the motion of the helicopter itself. To control such a system, a control method is needed that can cope with these complex dynamics.
In this paper, an investigation is performed on how to model and control a helicopter and a dipping SONAR through the suspension cable using incremental nonlinear dynamic inversion (INDI) as well as a comparison between the use of INDI and linear proportional integral derivative (PID) control. The controller uses only the cable states at the attachment point of the cable to the helicopter in order to determine the control inputs to the helicopter. This means that only these measurements are needed and no complex model of the cable is required for control. This reduces model dependency of the controller.
The control system is simulated in different wind conditions in order to analyse its performance in turbulent conditions, where the cable changes shape constantly. It was found that, although INDI performs better than PID control at low wind speeds, an INDI position hold controller appeared to perform better than an INDI cable controller at high wind speeds.

Incremental nonlinear control is a promising control method that can be applied in controlling tasks that involve systems with highly nonlinear dynamics. Incremental nonlinear control is a feedback linearization method that requires less model knowledge than conventional Nonlinear Dynamic Inversion and is robust against model mismatches. This thesis presents an incremental based control method to control a longitudinal model of the XV-15 tiltrotor aircraft. Firstly, an attitude controller is designed that solves the over actuated system of tiltrotor’s longitudinal cyclic and elevator pitch control by using a weighted least squares control allocation method. Secondly, an incremental based velocity controller is designed which integrates the use of the tiltrotor nacelles. The controllers have been tested against attitude and speed tracking tasks to evaluate their performance. The attitude controller showed to be able to follow the reference signal while adjusting to the changing aircraft dynamics. In combination with the velocity controller, the aircraft was able to follow a complete speed profile starting from the tiltrotor’s helicopter mode to the final fixed-wing mode and back. It was demonstrated that this transition manoeuvre could be performed in a fully coordinated way within the tiltrotor’s conversion corridor.

Due to their highly coupled and non-linear behavior, helicopters seem excellent subjects to apply non-linear control theory to. Furthermore, the rotor is operating in its own wake, leading to complex aerodynamics. A Command Filtered Incremental Backstepping controller has been applied to a simulation model of an MBB Bo-105 hingeless rotorcraft. The model incorporates the Pitt-Peters inflow model to calculate the inflow variations of the main rotor. Incremental controllers rely on sensor measurements of state derivatives instead of model knowledge, making them robust to modelling errors. However, some states of the helicopter model, such as blade flap angles and rotor inflow, cannot be measured in real life. Therefore a process called residualization and synchronization is used to remove these states from the controller model and compensate for their dynamics in a synchronization filter. This process has already been performed for the flap angles. In this thesis the inflow states are also residualized and added to the synchronization filter. Furthermore, the Pitt-Peters inflow model of the simulation model is updated with the Keller correction to better simulate off-axis response to control input. Modelling the off-axis response of helicopters is notoriously difficult and is often of the wrong sign compared to experimental data. Having a more precise helicopter model is key to perform piloted simulation or research to non-linear controllers. Although the updated inflow model did alter the inflow states, changes in the helicopter dynamics remained very limited. Furthermore, the application of residualization was successful but synchronizing the rotor inflow did not improve controller performance.

The interest in developing electric vertical takeoff and landing (eVTOL) vehicles has increased sharply in recent years. A concern for passenger acceptance of the new type of vehicle is that people may experience motion sickness. This is because eVTOL flight profiles are different from the motion conditions that people have previously experienced. The aim of this study was to predict the incidence of motion sickness amongst eVTOL passengers. To achieve this, a two degrees of freedom (2DOF) lateral theoretical motion sickness model was developed, with lateral acceleration and roll rate as inputs. The model parameters were tuned with data collected from flight simulator experiments performed in the SIMONA Research Simulator at the TU Delft. The participants (N=20) completed five trials, each time being exposed to one of five flight profiles: four eVTOL profiles (1—nominal condition, 2—high turbulence, 3—alternative control law, 4—seats turned 180°; t=24 min) and one helicopter profile (5—helicopter, t=31 min). Motion sickness severity in participants was measured using verbal ratings on the MIsery SCale (MISC). A significant difference was found between the MISC data for Profiles 1 and 2, showing that turbulence worsens motion sickness severity for passengers. No significant difference was found between Profiles 1 and 3 and between Profiles 1 and 4. The difference between the data from Profiles 1 and 5 was found to be statistically significant. However, given the discrepancy in how the two profiles were generated, further studies are needed to conclude whether flying in a helicopter in general induces more motion sickness than flying in an eVTOL. The 2DOF model was extended to 3DOF by adding vertical acceleration as input. After tuning both models with experimental data (mean MISC scores per participant), it was concluded that the 3DOF motion sickness predictions followed the trend of the measurements better than the ones of the 2DOF model. The developed models can be used for eVTOL design optimisation. To further improve the accuracy of the predictions, the 3DOF model will be extended to 6DOF in future studies.

The demand for online shopping has grown tremendously in the last couple of years. Picnic, a major player in the online grocery industry, is struggling to achieve long-term growth within its current operations. Scheduling and planning are key drivers for maintaining operational efficiency. The Fulfilment Centre (FC) and Distribution Centre (DC) costs heavily depend on efficient operations. This research focuses on improving the scheduling process in an e-grocery FC and DC. The main objective of the model is to maximise the quality of the schedule, which is achieved through two lexicographical objectives. First, the make span is minimised to improve efficiency and to calculate the number of employees required to fulfil the workload. The make span of a schedule is defined as the time between the first scheduled activity i and the last activity j in a schedule s. Next, the number of switches between activities is reduced. The second objective is to increase overall productivity since switching moments cause slack in the operations. Two solution methods are proposed to solve the Flexible Resource Constrained Project Scheduling Problem (FRCPSP). The first solution method is a Mixed Integer Linear Programming (MILP) formulation that is solved with a Branch & Cut (B&C) algorithm. Next, a meta-heuristic is proposed named Variable Neighbourhood Search (VNS). The initial solution is computed by solving the MILP for one objective, minimising the make span. Next, the VNS uses nested neighbourhoods to modify the answer resulting in fewer switches per schedule. For small instances, the exact formulation outperforms the meta-heuristic in most cases. Conversely, the meta- heuristic features a higher efficacy and efficiency when tackling more significant instances, being the only solution method capable of yielding feasible solutions for real-world scheduling problems. Despite the effectiveness of the proposed meta-heuristic, some operational adjustments are still required before implementing the proposed decision-making tool.

State-of-the-art tilt-rotor flight mechanics models appear to be inadequate in predicting the flight dynamics behavior across the entire flight envelope due to a lack of experimental data suggesting the need for more generic models. This paper presents a middle ground between model flexibility (genericity) and accuracy. For this purpose a generic 7-degrees-of-freedom tilt-rotor flight mechanics model is derived analytically. A novel ordering scheme is employed ensuring a bounded expression simplification error which is not found in existing tilt-rotor models. The research highlights the effects of the tiltable nacelle on the rotor analytical expressions and static flight mechanics. The model is validated against the XV-15 implementation of the NASA GTRS model showing promising overlap. It is concluded that the tiltable nacelle mainly affects the rotor expressions through the velocity experienced by the rotor hub and blade element, and that the nacelle tilt rate and acceleration are considered significant contributors to many rotor expressions. It is also shown that the nacelle tilt rate has an observable effect on handling and performance. Terms unique to tiltable proprotors are shown to exist, most notably the Coriolis effect of the nacelle tilt on the flapping dynamics. Several assumptions common in tilt-rotor modeling are also shown to be grossly violated. The future recommendation is to incorporate more sophisticated wing, control surface, and fuselage models, while the rotor model should include disk tilt and inflow dynamics, and a non-uniform inflow distribution.