• Title/Summary/Keyword: Differential-drive steering

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A Fusion Algorithm of Pure Pursuit and Velocity Planning to Improve the Path Following Performance of Differential Driven Robots in Unstructured Environments (차동 구동형 로봇의 비정형 환경 주행 경로 추종 성능 향상을 위한 Pure pursuit와 속도 계획의 융합 알고리즘)

  • Bongsang Kim;Kyuho Lee;Seungbeom Baek;Seonghee Lee;Heechang Moon
    • The Journal of Korea Robotics Society
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    • v.18 no.3
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    • pp.251-259
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    • 2023
  • In the path traveling of differential-drive robots, the steering controller plays an important role in determining the path-following performance. When a robot with a pure-pursuit algorithm is used to continuously drive a right-angled driving path in an unstructured environment without turning in place, the robot cannot accurately follow the right-angled path and stops driving due to the ground and motor load caused by turning. In the case of pure-pursuit, only the current robot position and the steering angle to the current target path point are generated, and the steering component does not reflect the speed plan, which requires improvement for precise path following. In this study, we propose a driving algorithm for differentially driven robots that enables precise path following by planning the driving speed using the radius of curvature and fusing the planned speed with the steering angle of the existing pure-pursuit controller, similar to the Model Predict Control control that reflects speed planning. When speed planning is applied, the robot slows down before entering a right-angle path and returns to the input speed when leaving the right-angle path. The pure-pursuit controller then fuses the steering angle calculated at each path point with the accelerated and decelerated velocity to achieve more precise following of the orthogonal path.

A Novel Motor Drive System for Electric Vehicle (전기자동차용 전동기 구동시스템의 개발)

  • Choi, Hyung-Mook;Sul, Seung-Ki
    • Proceedings of the KIEE Conference
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    • 1993.11a
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    • pp.151-153
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    • 1993
  • This paper proposes a novel motor drive system for the electric vehicle. In this paper, four-wheel-direct-drive type electric vehicle system is designed and the theoretical and experimental analysis of the system is investigated. The concept of steering not with steering the wheels but with the difference of the motor torque fives the flexibility of the vehicle design and, allows the omission of the differential gear, transmission gear, and drive axles. Thus the proposed system gives the space between wheels and improves the driver's steering performance.

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Controller for Single Line Tracking Autonomous Guidance Vehicle Using Machine Vision

  • Shin, Beom-Soo;Choi, Young-Dae;Ying, Yibin
    • Agricultural and Biosystems Engineering
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    • v.6 no.2
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    • pp.47-53
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    • 2005
  • AMachine vision is a promising tool for the autonomous guidance of farm machinery. Conventional CCD camera for the machine vision needs a desktop PC to install a frame grabber, however, a web camera is ready to use when plugged in the USB port. A web camera with a notebook PC can replace existing camera system. Autonomous steering control system of this research was intended to be used for combine harvester. If the web camera can recognize cut/uncut edge of crop, which will be the reference for steering control, then the position of the machine can be determined in terms of lateral offset and heading angle. In this research, a white line was used as a cut/uncut edge of crop for steering control. Image processing algorithm including capturing image in the web camera was developed to determine the desired travel path. An experimental vehicle was constructed to evaluate the system performance. Since the vehicle adopted differential drive steering mechanism, it is steered by the difference of rotation speed between left and right wheels. According to the position of vehicle, the steering algorithm was developed as well. Evaluation tests showed that the experimental vehicle could travel within an RMS error of 0.8cm along the desired path at the ground speed of $9\sim41cm/s$. Even when the vehicle started with initial offsets or tilted heading angle, it could move quickly to track the desired path after traveling $1.52\sim3.5m$. For turning section, i.e., the curved path with curvature of 3 m, the vehicle completed its turning securely.

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Online Control of DC Motors Using Fuzzy Logic Controller for Remote Operated Robots

  • Prema, K.;Kumar, N. Senthil;Dash, Subhransu Sekhar
    • Journal of Electrical Engineering and Technology
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    • v.9 no.1
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    • pp.352-362
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    • 2014
  • In this paper, a fuzzy logic controller is designed for a DC motor which can be used for navigation control of mobile robots. These mobile robots can be used for agricultural, defense and assorted social applications. The robots used in these fields can reduce manpower, save human life and can be operated using remote control from a distant place. The developed fuzzy logic controller is used to control navigation speed and steering angle according to the desired reference position. Differential drive is used to control the steering angle and the speed of the robot. Two DC motors are connected with the rear wheels of the robot. They are controlled by a fuzzy logic controller to offer accurate steering angle and the driving speed of the robot. Its location is monitored using GPS (Global Positioning System) on a real time basis. IR sensors in the robot detect obstacles around the robot. The designed fuzzy logic controller has been implemented in a robot, which depicts that the robot could avoid obstacle as well as perform its operation efficiently with remote online control.

Improvement of Energy Efficiency for an Omnidirectional Mobile Robot with Steerable Omnidirectional Wheels (조향 가능한 전방향 바퀴를 갖는 전방향 이동로봇의 에너지 효율 개선)

  • Song Jae-Bok;Kim Jeong-Keun
    • Journal of Institute of Control, Robotics and Systems
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    • v.11 no.8
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    • pp.696-703
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    • 2005
  • Since most autonomous mobile robots are powered by a battery, it is important to increase the continuous operating time without recharging. This can be achieved by improving the energy efficiency of a mobile robot, but little research on energy efficiency has been performed. This paper proposes two methods for improving the energy efficiency of an omnidirectional mobile robot.. One method is to realize a continuously variable transmission (CVT) by adopting the mechanism of steerable omnidirectional wheels. The other is the proposed steering algorithm in which wheel arrangement of the mobile robot is continuously adjusted so as to obtain the maximum energy efficiency of the motors during navigation. In addition, new omnidirectional wheels which can be transformed to the conventional wheels depending on the driving conditions are proposed to compensate for less efficient omnidirectional drive mode. Various tests show that motion control of the OMR-SOW works satisfactorily and the proposed steering algorithm for CVT can provide higher energy efficiency than the algorithm using a fixed steering angle. In addition, it is shown that the differential drive mode can give better energy efficiency than the omnidirectional drive mode.

Path control of a mobile robot 'KMR-2' using odometer system (거리계를 이용한 이동로보트 'KMR-2'의 경로주행제어에 관한 연구)

  • 조형석;이대업;이종원
    • 제어로봇시스템학회:학술대회논문집
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    • 1988.10a
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    • pp.142-147
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    • 1988
  • Free-path-type guidance system does not need a hardwired path in the environment so that it gives a mobile robot a flexible path. ln this study to achieve the free-path-type guidance system for a mobile robot which is steered by the differential steering of both drive forewheels, position recognition systems are constructed using odometer system as an internal position sensor. Two odometer systems, a auxiliary wheel odometer and a 2-encoder odometer system are constructed and path following algorithms using these odometer systems are designed and experimented. PID control type is adopted in the path following algorithms.

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Automated Technology for Pipelines Inspection Using Inpipe Robot (배관 로봇을 이용한 배관 검사 자동화 기술)

  • Roh, Se-Gon;Choi, Hyouk-Ryeol
    • Journal of the Korean Society for Nondestructive Testing
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    • v.22 no.3
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    • pp.261-266
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    • 2002
  • Up to now a wide variety of researches on inpipe robots for inspection have been introduced, but it still seems to be difficult to construct a robot providing mobility sufficient to navigate inside the complicated configuration of underground pipelines. The robot for the inspection of pipelines should freely move along the basic configuration of pipelines such as along horizontal or vertical pipelines. Moreover it should be able to travel along reducers and elbows, and especially the capability for steering in branches is essential to it. In this report, citical points and technologies in the development of the inpipe inspection robots are introduced and inpipe robots developed for last several years are introduced.