전정환 교수

We discuss an implementation of the RRT* optimal motion planning algorithm for the half-car dynamical model to enable autonomous high-speed driving. To develop fast solutions of the associated local steering problem, we observe that the motion of a special point (namely, the front center of oscillation) can be modeled as a double integrator augmented with fictitious inputs. We first map the constraints on tire friction forces to constraints on these augmented inputs, which provides instantaneous

Incremental sampling-based motion planning algorithms such as the Rapidly-exploring Random Trees (RRTs) have been successful in efficiently solving computationally challenging motion planning problems involving complex dynamical systems. A recently proposed algorithm, called the RRT*, also provides asymptotic optimality guarantees, i.e., almost-sure convergence to optimal trajectories (which the RRT algorithm lacked) while maintaining the computational efficiency of the RRT algorithm. In this pa

One long-standing challenge in robotics is the realization of mobile autonomous robots able to operate safely in existing human workplaces in a way that their presence is accepted by the human occupants. We describe the development of a multi-ton robotic forklift intended to operate alongside human personnel, handling palletized materials within existing, busy, semi-structured outdoor storage facilities. The system has three principal novel characteristics. The first is a multimodal tablet that

One long‐standing challenge in robotics is the realization of mobile autonomous robots able to operate safely in human workplaces, and be accepted by the human occupants. We describe the development of a multiton robotic forklift intended to operate alongside people and vehicles, handling palletized materials within existing, active outdoor storage facilities. The system has four novel characteristics. The first is a multimodal interface that allows users to efficiently convey task‐level command

The RRT* algorithm has efficiently extended Rapidly-exploring Random Trees (RRTs) to endow it with asymptotic optimality. We propose Goal-Rooted Feedback Motion Trees (GR-FMTs) that honor state/input constraints and generate collision-free feedback policies. Given analytic solutions for optimal local steering, GR-FMTs obtain and realize safe, dynamically feasible, and asymptotically optimal trajectories toward goals. Second, for controllable linear systems with linear state/input constraints, we

This research identifies factors that affect the technological transition of firms toward industry 4.0 (IT) technologies focusing on capabilities and policy impacts using relatedness and complexity measures. For the analysis, a unique dataset was used of Korean manufacturing firms’ patents and their financial and market information. Following the Principle of Relatedness, which is a recently shaped empirical principle in the field of economic complexity, economic geography, and regional studies,

This paper examines the technological structures of the manufacturing and the ICT sectors in Korea to examine the potential shift of dominant technological sectors in the era of the Fourth Industrial Revolution (4IR). By using patent data of Korean firms from 1990 to 2021, we find that the manufacturing sector has been the dominant technological leader in Korea in terms of both the number of patents and the diversity of technologies, even in the era of 4IR. Although the ICT sector has shown an i

This study proposes a new integrated approach to the motion control of autonomous vehicles, which differs from the conventional method of treating planning and tracking tasks as separate or hierarchical components. By means of the proposed approach we can reduce the side effects on the performance of autonomous vehicles under challenging driving circumstances. To this end, our approach processes both of the aforementioned tasks asynchronously and simultaneously utilizes a multi-threaded architec

Abstract This paper extends the RRT* algorithm, a recently developed but widely used sampling based optimal motion planner, in order to effectively handle nonlinear kinodynamic constraints. Nonlinearity in kinodynamic differential constraints often leads to difficulties in choosing an appropriate distance metric and in computing optimized trajectory segments in tree construction. To tackle these two difficulties, this work adopts the affine quadratic regulator-based pseudo-metric as the distance

This paper introduces a robust adaptive path-tracking control scheme via a predicted interval approach for safe autonomous driving tasks under uncertainties. Specifically, a recursive least squares-based set-membership mechanism is firstly designed to estimate a bounding set of acceptable values to depict the uncertain parameters. Based on the estimated system parameters, an interval predictor is deployed to improve the prediction accuracy in the primary control action design. Successively, the

This research aims to identify factors that affect the technological transition of firms toward industry 4.0 technologies (I4Ts) focusing on firm capabilities and policy impact using relatedness and complexity measures. For the analysis, a unique dataset of Korean manufacturing firms' patent and their financial and market information was used. Following the Principle of Relatedness, which is a recently shaped empirical principle in the field of economic complexity, economic geography, and region

This work presents a finite-time robust path-following control scheme for perturbed autonomous ground vehicles. Specifically, a novel self-tuning nonsingular fast-terminal sliding manifold that further enhances the convergence rate and tracking accuracy is proposed. Then, uncertain dynamics and external disturbances are estimated by a high-gain disturbance observer to compensate for the designed control input. Successively, a super-twisting algorithm is incorporated into the final control law, s

This paper presents an efficient motion planning framework for a perturbed linear system using a minimax objective function while ensuring the safety of the system. Specifically, the proposed approach is naturally deployed to handle model uncertainties by a recursive least squares-based set-membership mechanism. Next, a minimax-based objective optimization problem is formed to handle the goal flexibility. The robust model predictive control algorithm is then designed to solve this robust optimiz

In this study, a cooperative monitoring task for multiple anti-aircraft targets is investigated using multiple unmanned aerial vehicles (UAVs) equipped with stereo vision sensors. To accomplish this task, these UAVs must cooperate with other UAVs within a three-dimensional (3D) space to track multiple targets and avoid collisions. To address this challenge, we propose a cooperative multiagent reinforcement learning (MARL) scheme that can make intelligent flight decisions to enable multiple UAVs