Kwangseok Oh

Development and Validation of Wheel Loader Simulation Model

건설기계를 이용한 대규모 토목공사에서 휠로더Key Words: Driving Powertrain(주행부 동력전달), Hydraulic Powertrain(유압부 동력전달), Hydraulic Cylinder Model(유압 실린더 모델), Main Relief Valve(메인 릴리프 밸브), Main Control Valve(메인 릴리프 밸브), Check Valve(체크밸브), Parallel Axis Theorem(평행축 정리) 초록: 본 논문은 Matlab/simulink 기반 휠로더 시뮬레이션 모델의 개발과 검증에 대한 논문이다. 휠로더 시뮬레이션 모델의 개발 및 검증은 실제 휠로더의 생산단계에 앞서 휠로더의 성능을 평가하고 개선하기 위한 목적을 두고 있다. 휠로더 시뮬레이션 모델은 전체적으로 주행부/유압부 동력전달계 모델, 주행부/작업장부 동역학 모델을 포함한4가지 모델로 나뉘어져 있다. 휠로더의 주행 및 작업성능을 평가하고 개선하기 위해서는 언급된 4 가지 모델의 통합 시뮬레이션이 필요하며 통합된 시뮬레이션 모델은 성능평가 외의 연료효율의 최적화, 하이브리드 시스템 및 지능형 휠로더 모델의 개발로써 작업효율 향상에 기여할 수 있을 것이다. 본 논문에 제안된 시뮬레이션 모델은 주행부와 작업부 실험 데이터와의 비교를 통해 검증 되었다. Abstract: This paper presents the development and validation of a wheel loader simulation model. The objective of doing so is to evaluate the performance of the wheel loader and improve its overall performance using Matlab/Simulink. The wheel loader simulation model consists of 4 parts: mechanical/hydraulic powertrain model and vehicle/working dynamic model. An integrated simulation model is required to evaluate and improve the performance of the wheel loader. It is expected that this model will be applied to fuel economizing, improving the pace of operation by using the hybrid system, and the intelligent wheel loader. The performance of the proposed simulation model has been validated by using Matlab/Simulink to compare the driving and the working experimental data.

An investigation on steering optimization for minimum turning radius of multi-axle crane based on MPC algorithm

The study investigates on the optimized steering wheel angle for minimum turning radius of all-terrain crane by applying a model predictive control (MPC) strategy. For this, the simplified linear bicycle model and error dynamic model are firstly derived for the crane with a multi-axle steering system. Then, MPC controller is designed with an optimal objective function to minimize the vehicle dynamic error for minimum turning radius. The minimum turning radius and corresponding optimized steering angle at different vehicle speeds are analyzed in the MATLAB/Simulink environment.

A predictive driver model with physical constraints for closed loop simulation of vehicle-driver system

This paper presents a longitudinal and lateral predictive driver model. The predictive driver model has been designed for closed loop simulation of vehicle-driver system. Preview, prediction, manipulation update and speed planning characteristics are considered as human driver characteristics. Human driver generally decelerates when the driver drives on curved path not to exceed expected lateral acceleration by driver. In this paper, Model Predictive Control (MPC) is used to represent human driver model characteristics. MPC design incorporates all constraints on state, control and output variables. And the constraints are used in driver model in order to represent drivability of human driver. Planned speed by human driver is considered in MPC receding prediction horizon to determine steering angle on curved path. Simulation results show that the proposed human driver model can represent actual human driver characteristics and also shows the feasibility of the MPC algorithm in real-time application.

Development of Wheel Loader V-Pattern Operator Model for Virtual Evaluation of Working Performance

* School of Mechanical and Aerospace Engineering, Seoul Nat’l Univ.** Hyundai Heavy Industries Co., LTD. (Received February 12, 2014 ; Revised July 18, 2014 ; Accepted August 1, 2014)Key Words: Event(이벤트), V-Pattern Working(V상차 작업), Operator Model(운전자 모델)초록: 본 논문에서는 가상의 V상차 작업을 위한 이벤트 기반의 휠로더 운전자 모델을 개발하였다. 운전자 모델 개발의 목적은 휠로더의 일반적인 작업인 V상차 작업 시 동역학적 해석과 작업성능을 가상의 시뮬레이션 모델과 운전자 입력을 이용해 예측 및 평가하는 것이다. V상차 작업은 4단계로 이루어져 있으며, 총 8 개의 이벤트로 인해 순차적으로 작업이 진행된다. 개발된 3D 휠로더 시뮬레이션 모델은 Matlab/Simulink 환경에서 구성 되었으며, 시뮬레이션 결과는 V상차 작업의 실차 데이터와 비교 되었다. 본 연구에서 개발된 운전자 모델로 향후 가상의 V상차 작업에 대한 작업성능 및 동역학적 해석이 가능할 것으로 본다.Abstract : This paper presents the development of an event-based operator model of a wheel loader for virtual V-pattern working. The objective of this study is to analyze the performance and dynamic behavior of the wheel loader for a typical V-pattern. The proposed typical V-pattern working is divided into four stages. The developed operator model is based on eight events, and the operators inputs are occurred sequentially by event. A 3D dynamic simulation model of the wheel loader is developed and used to analyze the dynamic behavior during working, and the simulation results are compared with the experimental data of V-pattern working. The proposed 3D dynamic simulation model and operator model are constructed using MATLAB/Simulink. The proposed operator model for V-pattern working is expected to enable evaluation of the working performance and dynamic behavior of the wheel loader.