• Title, Summary, Keyword: Two-wheels

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A Study On Steering System for Mobile Robot with Permanent Magnet Wheels (영구자석 바퀴를 이용한 이동 로봇의 조향 시스템 연구)

  • Kim Jin-Gak;Yi Hwa-Cho;Han Seung-Chul
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.311-312
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    • 2006
  • In this paper, steering systems for mobile robot with permanent magnet wheels are discussed. The mobile robot with permanent magnet wheels can have three different types of steering and driving configurations; two-wheels, three-wheels, four-wheels. By a Two-WD(Wheel Driving) system, driving and steering characteristics are controlled by ratio of each wheel speeds. Three-WD system is steered by a front wheel and driven by rear wheels. Four-WD system has better stability than two wheel system. Usually the permanent magnet wheel has nearly none slip. Thus turning radius of the mobile robot with three-WD and four-WD System will be increased and the steering and driving system will be complicated. To solve this problem, two magnet wheels with two dummy wheels are used in this study. fuming radius of the developed mobile robot is small and the structure of the robot is simple. It is possible to move forward, backward, to turn left and right, and to rotate freely with two-WD. This study proved that two-WD system is very suitable fur the mobile robot with permanent magnet wheels.

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Nonlinear Nutation Control of Spacecraft Using Two Momentum Wheels

  • Seo, In Ho;Kim, Jong Myeong;Leeghim, Henzeh
    • International Journal of Aeronautical and Space Sciences
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    • v.18 no.1
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    • pp.99-107
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    • 2017
  • In this work, the nutation control of rigid spacecraft with only two momentum wheels is addressed by applying the feedback linearization technique. In this strategy, the primary performance index is to regulate the nutational angle by the momentum control of wheels. The spacecraft attitude equations of motion are transformed to a general linearized form by feedback linearization technique, including a guaranteed control law promising the internal dynamics stability to accomplish the nutation angle small. It is proven that the configuration of inertia properties plays a key role in analyzing spacecraft energy level. The behavior of the momentum wheels is also studied analytically and numerically. Finally, the effectiveness of the proposed nonlinear control law for the momentum transfer is verified by conducting numerical simulations.

Vibration of vehicle-bridge coupling system with measured correlated road surface roughness

  • Han, Wanshui;Yuan, Sujing;Ma, Lin
    • Structural Engineering and Mechanics
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    • v.51 no.2
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    • pp.315-331
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    • 2014
  • The present study investigated the effect of the correlation of the measured road roughness profiles corresponding to the left and right wheels of a vehicle on the vibration of a vehicle-bridge coupling system. Four sets of road roughness profiles were measured by a laser road-testing vehicle. A correlation analysis was carried out on the four roughness samples, and two samples with the strongest correlation and weakest correlation were selected for the power spectral density, autocorrelation and cross-correlation analyses. The scenario of a three-axle truck moving across a rigid-frame arch bridge was used as an example. The two selected road roughness profiles were used as inputs to the vehicle-bridge coupling system. Three different input modes were adopted in the numerical analysis: (1) using the measured road roughness profile of the left wheel for the input of both wheels in the numerical simulation; (2) using the measured road roughness profile of the right wheel for both wheels; and (3) using the measured road roughness profiles corresponding to left and right wheels for the input corresponding to the vehicle's left and right wheels, respectively. The influence of the three input modes on the vibration of the vehicle-bridge system was analyzed and compared in detail. The results show that the correlation of the road roughness profiles corresponding to left and right wheels and the selected roughness input mode both have a significant influence on the vibration of the vehicle-bridge coupling system.

Time Optimal Attitude Maneuver Strategies for the Agile Spacecraft with Reaction Wheels and Thrusters

  • Lee Byung-Hoon;Lee Bong-Un;Oh Hwa-Suk;Lee Seon-Ho;Rhee Seung-Wu
    • Journal of Mechanical Science and Technology
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    • v.19 no.9
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    • pp.1695-1705
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    • 2005
  • Reaction wheels and thrusters are commonly used for the satellite attitude control. Since satellites frequently need fast maneuvers, the minimum time maneuvers have been extensively studied. When the speed of attitude maneuver is restricted due to the wheel torque capacity of low level, the combinational use of wheel and thruster is considered. In this paper, minimum time optimal control performances with reaction wheels and thrusters are studied. We first identify the features of the maneuvers of the satellite with reaction wheels only. It is shown that the time-optimal maneuver for the satellite with four reaction wheels in a pyramid configuration occurs on the fashion of single axis rotation. Pseudo control logic for reaction wheels is successfully adopted for smooth and chattering-free time-optimal maneuvers. Secondly, two different thrusting logics for satellite time-optimal attitude maneuver are compared with each other: constant time-sharing thrusting logic and varying time-sharing thrusting logic. The newly suggested varying time-sharing thrusting logic is found to reduce the maneuvering time dramatically. Finally, the hybrid control with reaction wheels and thrusters are considered. The simulation results show that the simultaneous actuation of reaction wheels and thrusters with varying time-sharing logic reduces the maneuvering time enormously. Spacecraft model is Korea Multi-Purpose Satellite (KOMPSAT)-2 which is being developed in Korea as an agile maneuvering satellite.

Implementation and Balancing Control of a Robotic Vehicle for Entertainment (엔터테인먼트용 로봇차량의 제작과 균형 제어)

  • Kim, Hyun Wook;Cho, Seong-Taek;Jung, Seul
    • Journal of Institute of Control, Robotics and Systems
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    • v.20 no.7
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    • pp.736-740
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    • 2014
  • This paper presents the driving and balancing control of an entertainment robot vehicle that can carry two persons. The entertainment robot vehicle is built with the purpose of carrying passengers with two wheels. It has two driving modes: a balancing mode with two wheels and a driving mode with three wheels. Three cases of different modes are verified by experimental studies. Firstly, a driving mode is tested with two passengers to check the functionality of the vehicle. Secondly, the balancing control performance is tested. Lastly, the balancing control performance under the disturbance is tested.

Study on an 8-Wheel Suspension to Enhance the Hill-Climbing Performance for a Planetary Exploration Rover

  • Eom, We-Sub;Lee, Joo-Hee;Gong, Hyun-Cheol;Choi, Gi-Hyuk
    • Journal of Astronomy and Space Sciences
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    • v.31 no.4
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    • pp.347-351
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    • 2014
  • Planetary exploration rovers are likely to make a trip on a winding and sloping road of irregular surfaces to the destination in order to accomplish scientific missions. One of the key technologies for rovers is a suspension for traveling and performing exploration missions; the suspension is an essential area of technology for a stable movement of a rover. In this study, an 8-wheel suspension is designed to enable efficient climbing of slopes on a passage to the destination. For the two front wheels among the eight wheels, the moment at the pivot connecting two wheels is derived when the distance between the wheels and the torque of wheels are same. A test experiment was performed to compare the magnitude of moment according to the change in tilt angle and the position of the pivot. Finally, a suspension design considering the position of the pivot was proposed to enhance the hill-climbing performance.

The Azimuth and Velocity Control of a Mobile Robot with Two Drive Wheels by Neural-Fuzzy Control Method (뉴럴-퍼지제어기법에 의한 두 구동휠을 갖는 이동형 로보트의 자세 및 속도 제어)

  • Cho, Y.G.;Bae, J.I.
    • Journal of Power System Engineering
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    • v.2 no.3
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    • pp.74-82
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    • 1998
  • This paper presents a new approach to the design of speed and azimuth control of a mobile robot with two drive wheels. The proposed control scheme uses a Gaussian function as a unit function in the neural-fuzzy network and back propagation algorithm to train the neural-fuzzy network controller in the framework of the specialized learning architecture. It is proposed to a learned controller with two neural-fuzzy networks based on an independent reasoning and a connection net with fixed weights to simplify the neural-fuzzy network. The performance of the proposed controller can be seen by the computer simulation for trajectory tracking of the speed and azimuth of a mobile robot driven by two independent wheels.

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Fracture of Grinding Wheels and Surface Roughness in Surface Grinding for the various Grinding Wheels and Grinding Conditions (평면연삭에서 숫돌의 종류와 연삭조건에 따른 표면거칠기 및 연삭숫돌의 파괴)

  • 오동석;이병곤;이종훈
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.10 no.4
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    • pp.118-122
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    • 2001
  • In this study, the variation of surface roughness was tested in surface grinding for the three working materials SM45C, heat-treated SM45C, and gray cat iron. IT was performed for the various grinding wheels with two grain size #60, #100, and three grade I, O, R and various grinding depths and feeds, The fractural grinding depths which were obtained when the grinding wheels were destructed in surface grinding works, were examined and compared with the calculated value sug-gested in this study, The results showed that the surface roughness was decreased by decreasing grinding depth, and feed, and increasing grain size and grades. The fracture grinding depths were increased by increasing grain size, grade and feed.

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Development of the Two-piece Aluminum Wheels Using the Friction Stir Welding (마찰교반용접법을 이용한 2피스 알루미늄 휠의 개발)

  • Choi, In-Young;Kang, Young-June;Kim, Andrey;Ahn, Kyu-Saeng
    • Journal of The Korean Society of Manufacturing Technology Engineers
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    • v.22 no.4
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    • pp.700-707
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    • 2013
  • Owing to high oil prices and environmental issues, the automobile industry has conducted considerable research and made large investments to manufacture a high-efficiency automobiles. In the case of automobile wheels in which a lightweight material is used to increase the fuel efficiency a mold is used to increase the production efficiency; however, the use of the molding method for this purpose is very expensive. Therefore an automobile wheel consists of two parts. In this study a two-piece automobile wheel is manufactured by the friction stir welding(FSW) of Al6061-T6 to reduce the manufacturing cost and process complexity. The FSW welding tool geometry and rotational speed, and the feed rate are key factors that significantly affect the weld strength. Therefore tensile tests were conducted on specimens produced using various welding conditions, and the optimal FSW welding conditions were applied to manufacture aluminum wheels. To ensure reliability, prototype aluminum wheels were manufactured and their mechanical reliability and safety were evaluated using a durability test, fatigue durability test, and impact test. Through this study, aluminum wheel production was made possible using the FSW method.

Unified-type Design and Structural Analysis for Mecanum Wheel Performance Improvement (메카넘휠 성능개선을 위한 일체형 설계 및 구조해석)

  • Jeong, Jeaung;Kwon, Soon-Jae;Chu, Baeksuk;Park, Junyoung
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.13 no.2
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    • pp.117-123
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    • 2014
  • In order to provide a mobile robot with omnidirectionality, various types of omnidirectional wheels have been developed. This paper deals with an improved design and structural analysis of a Mecanum wheel, which is the type of omnidirectional wheels most commonly used in industrial fields. A geometric formulation for manufacturingthe Mecanum wheel is presented and two types of Mecanum wheels are designed and fabricated in this research. While conventional assembled-type Mecanum wheels have a complicated structure and the high possibility of mutual interference between sub-components, a unified type of Mecanum wheel reduces the number of sub-components and increases the degree of structural rigidity. The stress and strain properties of the two designs are compared to confirm the quantitative improvement of the new design by a commercial structural analysis tool. The analysis results show that the unified type of Mecanum wheel has properties superior to the assembled type of Mecanum wheel in terms of its ability to reduce interference.