Woong Kwon

Performance evaluation of decision making strategies for an embedded lane departure warning system

An on-board lane departure warning system embedded in a vehicle is composed of a localization module and a decision making module. The decision making module detects unintended lane departure so as to warn the driver of the danger. The performance of a decision making module is crucial to the performance of the total embedded system. This article proposes two heuristic decision making strategies: a lateral offset (LO) based strategy and a time-to-lane crossing (TLC) based strategy. The performance criteria of decision making strategies are proposed as: (1) false alarm rate, and (2) alarm triggering time (ATT). Numerical parameters of both strategies are optimized through numerical simulation, taking the performance criteria into consideration. The proposed strategies are incorporated into the prototype system and evaluated in real expressway experiments. The comparative study of both methods with experimental results shows the applicability of the on-board lane departure warning system.

Biped humanoid robot Mahru III

This paper presents a new biped humanoid robot Mahru III (150 cm, 62 Kg) developed by Samsung Electronics Co., Ltd in 2007. The ultimate goal of this project is to design biped humanoid robots connected to a wireless network environment so that they can be used in our daily life. As the first step, Mahru III was built as a pilot platform for future household companion robots. In this paper we focus on the design of the mechanical system, electrical/electronic parts, and the control algorithm with some experimental results. We designed the mechanical system to achieve lightweight, high stiffness and high energy efficiency through CAE(computer aided engineering) analysis and DOE(design of experiments)-based optimization. We also built an extensible electrical/electronic system to provide for future network-based applications. Walking control algorithm is realized to make stable walking on an uneven floor possible. The experiments of the first phase shows that our humanoid can walk at 1.3 km/h and overcome 1 cm protrusions successfully.

Experiments on decision making strategies for a lane departure warning system

Describes two decision making strategies of the lane departure warning system for a vehicle and provides experimental results to assess the performance of each strategy. The overview of the lane departure warning system mounted on the vehicle is presented. A lateral offset (LO) based strategy and a time to lane crossing (TLC) based strategy are proposed to be used in the warning module which detects unintended lane departure so as to warn the driver. The performance criteria of the warning strategies are defined as: 1) false alarm rate, 2) alarm triggering time. The proposed strategies are incorporated in our lane departure warning system to be tested in real expressway experiments. The experimental results for the performance optimization of both strategies are discussed and compared with each other.

A vision based lane departure warning system

Proposes a vision based lane departure warning system which warns the driver of drifting off the lane inattentively. An estimation algorithm is proposed to obtain the vehicle pose and lane geometry data so as to detect an unintended lane departure. The lane departure alarm is triggered by a warning algorithm which makes decisions on giving an alarm based on the data from the estimation algorithm. The performance criteria of the lane departure warning system are defined as false alarm rate and alarm triggering time. The system is implemented in a test automobile and tested in real expressway experiments optimizing the performance. The experimental results demonstrate the applicability of the proposed system.

Particle filter-based heading estimation using magnetic compasses for mobile robot navigation

Heading information is critical for the control and/or navigation of mobile devices and robots. To get accurate heading information robustly, we propose a method which combines particle filtering with magnetic compasses. Although magnetic compasses can provide absolute heading angle, they have not been used for indoor applications since serious magnetic interferences are commonly founded in home/office environments. We overcome this difficulty by 1) suggesting statistical calibration of a magnetic compass, 2) deriving necessary conditions of the Earths magnetic field area, and 3) designing an event-based particle filter based on likelihood calculated from conditional probability. Particle filter is an emerging key technology which can be applied to nonlinear/non-Gaussian model, beyond the limitations of Kalman filter. We take advantage of particle filter to optimally fuse the information from both magnetic compasses and odometry data. Experimental results on mobile robot navigation in indoor environments show reliability and robustness of the proposed method

Modeling and control of robotic surgical platform for single-port access surgery

In this paper, we present a modeling and control method for a single-port access robot developed by our robotics group at the Samsung Advanced Institute of Technology. The surgical robot consists of a snake-like 6-degree-of-freedom (DOF) guide tube, two 7-DOF tools, a 3-DOF stereo camera, and a 5-DOF slave arm. The robot is capable of reaching various surgical sites inside the abdominal cavity from a single incision on the body. To estimate the workspace and control the guide tube to a desired location, we first obtain the forward kinematics model of the guide tube and then propose a Cartesian-level controller. The wire actuation mechanism for the tools exhibit nonlinear backlash behavior because of wire compliance and friction between the wire and Teflon-coated conduit. We compensate for the backlash in the tool joints by adding the backlash inverse with smoothing term as a feedforward term.

Robust lane keeping from novel sensor fusion

This paper describes a vision based robust lane keeping system which warns the driver of inattentively drifting off the lane in such a way as to keep the vehicle in the lane. The overview of the lane keeping system mounted on the automobile is presented. A novel sensor fusion algorithm is proposed to estimate the vehicle pose and lane geometry data so as to detect an unintended lane departure. The performance criteria of decision making strategies of the lane keeping system are proposed as: 1) false alarm rate, and 2) alarm triggering time. Two heuristic decision making strategies of the lane keeping system are provided with experimental results evaluating the performance of each strategy.

Natural sit-down and chair-rise motions for a humanoid robot

We discuss a constructive procedure for planning human-like motions of humanoid robots on finite-time intervals. Besides complying with various constraints present in the robot dynamics, it allows us to reflect certain features of recorded and analyzed motions of a test person, even though the dimensions, the mass distribution, and the actuation of the robot are different. So, the steps in motion planning are complemented by a novel algorithm for control design to ensure contraction of the orbits of various perturbed closed-loop motions to the orbit of the prescribed target trajectory.

Resolving kinematic redundancy of a robot using a quadratically constrained optimization technique

The constraints on the physical limit should be considered in a kinematic redundancy resolution problem of a robot. This paper proposes a new optimization scheme to resolve kinematic redundancy of the robot while considering physical constraints. In the proposed scheme, quadratic inequality constraints are used in place of linear inequality constraints, thus a quadratically constrained optimization technique is applied to resolve the redundancy. It is shown that the use of quadratic inequality constraints considerably reduces the number of constraints. Therefore, the proposed method reduces the problem size considerably and makes the problem simple resulting in computational efficiency. A numerical example of a 4hlink planar redundant robot is included to demonstrate the efficiency of the proposed optimization technique. In this example, simulation results using the proposed method and another wellhknown method are compared and discussed.

A dynamic programming approach to a reel assignment problem of a surface mounting machine in printed circuit board assembly

We consider the problem of assigning reels of components to slots on feeder racks of a surface mounting machine which is used to populate printed circuit boards with surface mount technology. This reel assignment problem (RAP) is one of a series of optimization problems that should be addressed to improve the production rate. We preprocess RAP to facilitate the application of dynamic programming and then formulate it as an integer programming problem. We solve the problem by using a heuristic algorithm based on dynamic programming. We implement the algorithm as a computer program and perform computer simulations. The simulation results are compared to those of the Effective Algorithm previously proposed.