Multi-expert Preference Alignment in Reinforcement Learning

This project explores adaptation to preference shifts in Multi-objective Reinforcement Learning (MORL), with a focus on how Reinforcement Learning (RL) agents can align with the preferences of multiple experts. This alignment can occur across various scenarios featuring distinct preferences of experts or within a single scenario that experiences...

Incorporating climate change in I&M planning for engineering structures - A Deep Reinforcement Learning Framework

In the last decades, climate change is causing our environment to change rapidly, unprecedented in recent history. Civil engineering structures are dependent on the deteriorating environment they are situated in. Changes can cause an increase in loading due to, for example, extreme weather events or alter the structure’s resistance by, for...

Personalized and Adaptive Cognitive Human-Robot Interaction with a Novel Fuzzy Logic Control and Reinforcement Learning-Based Paradigm: Master Thesis Report

An aging population puts a pressure on health-care workers working with dementia patients globally. A potential solution is to provide care with Socially Assistive Robots (SARs), i.e. robots who help people through social interaction. However, for effective care these SARs must be able to personalize their behavior to individual patients and...

Reinforcement Learning for Flight Control: Hybrid Offline-Online Learning for Robust and Adaptive Fault-Tolerance

Recent advancements in fault-tolerant flight control have involved model-free offline and online Reinforcement Learning algorithms in order to provide robust and adaptive control to autonomous systems. Inspired by recent work on Incremental Dual Heuristic Programming (IDHP) and Soft Actor-Critic (SAC), this research proposes a hybrid SAC-IDHP...

Combining MPC and reinforcement learning in a model-reference framework for urban traffic signal control

Both model predictive control (MPC) and reinforcement learning (RL) have shown promising results in the control of traffic signals in urban traffic networks. There are, however, a few drawbacks. MPC controllers are not adaptive and therefore perform suboptimal in the presence of the uncertainties that always occur in urban traffic systems....

Design of Reinforcement Learning based Incremental Flight Control Laws for the Cessna Citation II(PH-LAB) Aircraft

Online Adaptive Flight Control is interesting in the context of growing complexity of aircraft systems and their adaptability requirements to ensure safety. An Incremental Approximate Dynamic Programming (iADP) controller combines reinforcement learning methods, optimal control and Online identified incremental model to achieve optimal adaptive...

Longitudinal Flight Control by Reinforcement Learning: Online Adaptive Critic Design Approach to Altitude Control

Reinforcement learning is used as a type of adaptive flight control. Adaptive Critic Design (ACD) is a popular approach for online reinforcement learning control due to its explicit generalization of the policy evaluation and the policy improvement elements. A variant of ACD, Incremental Dual Heuristic Programming (IDHP) has previously been...

Reinforcement Learning for Flight Control: Learning to Fly the PH-LAB

In recent years Adaptive Critic Designs (ACDs) have been applied to adaptive flight control of uncertain, nonlinear systems. However, these algorithms often rely on representative models as they require an offline training stage. Therefore, they have limited applicability to a system for which no accurate system model is available, nor readily...

Safer reinforcement learning for robotics

Reinforcement learning is an active research area in the fields of artificial intelligence and machine learning, with applications in control. The most important feature of reinforcement learning is its ability to learn without prior knowledge about the system. However, in the real world, reinforcement learning actions may lead to serious damage...

Adaptive Critic Control For Aircraft Lateral-Directional Dynamics: An Evaluation of J-SNAC Algorithm as a Fault Tolerant Flight Control Framework

Loss of control-in flight (LOC-I) is one of the causes of catastrophic aircraft accidents. Fault-tolerant flight control (FTFC) systems can prevent LOC-I and recover aircraft from its precursors. One group of promising methods for developing Fault-Tolerant Control (FTC) system is the Adaptive Critic Designs (ACD). Recently one ACD algorithm,...

Adaptation of a non-linear controller based on Reinforcement Learning

Closed-loop control systems, which utilize output signals for feedback to generate control inputs, can achieve high performance. However, robustness of feedback control loops can be lost if system changes and uncertainties are too large. Adaptive control combines the traditional feedback structure with providing adaptation mechanisms that adjust...

Online reinforcement learning control for aerospace systems

Reinforcement Learning (RL) methods are relatively new in the field of aerospace guidance, navigation, and control. This dissertation aims to exploit RL methods to improve the autonomy and online learning of aerospace systems with respect to the a priori unknown system and environment, dynamical uncertainties, and partial observability. In the...

Adaptive-Critic Designs For Aircraft Control: A comparative study between Heuristic Dynamic Programming and Dual Heuristic Programming

The Variable Camber Continuous Trailing Edge Flap (VCCTEF) is a novel aircraft control system that intents to prevent undesired aeroelastic deflections by precise lift tailoring along the wing span. However, the unknown dynamics and increased complexity of the new hardware imposes difficulties to establish an optimal controller. One approach is...