• Title/Summary/Keyword: repulsive function

Search Result 38, Processing Time 0.028 seconds

REPULSIVE FIXED-POINTS OF THE LAGUERRE-LIKE ITERATION FUNCTIONS

  • Ham, YoonMee;Lee, Sang-Gu
    • Korean Journal of Mathematics
    • /
    • v.16 no.1
    • /
    • pp.51-55
    • /
    • 2008
  • Let f be an analytic function with a simple zero in the reals or the complex numbers. An extraneous fixed-point of an iteration function is a fixed-point different from a zero of f. We prove that all extraneous fixed-points of Laguerre-like iteration functions and general Laguerre-like functions are repulsive.

  • PDF

Collision Avoidance for UAV using Potential Field based on Relative Velocity of Obstacles (장애물의 상대속도를 반영한 포텐셜필드 기반 무인항공기 충돌회피)

  • Ahn, Seung-gyu;Lee, Dongjin
    • Journal of the Korean Society for Aviation and Aeronautics
    • /
    • v.26 no.2
    • /
    • pp.47-53
    • /
    • 2018
  • In this paper, we investigate a collision avoidance algorithm for unmanned aerial vehicles using potential field based on the relative velocity of obstacles. The potential field consists of the attraction force and the repulsive force that are generated for the target and the obstacles. And the field can be classified into the attractive potential field generated by the target and the repulsive potential field generated by the obstacle, respectively. In this study, we construct an attractive potential field as a function of the distance between the UAV and the target position. On the other hand, a repulsive potential field is created by a function of distance and the relative velocity of the obstacle with respect to the UAV. The proposed potential field based collision avoidance algorithm is evaluate through simulations.

Hybrid Path Planning of Multi-Robots for Path Deviation Prevention (군집로봇의 경로이탈 방지를 위한 하이브리드 경로계획 기법)

  • Wee, Sung-Gil;Kim, Yoon-Gu;Choi, Jung-Won;Lee, Suk-Gyu
    • Journal of Institute of Control, Robotics and Systems
    • /
    • v.19 no.5
    • /
    • pp.416-422
    • /
    • 2013
  • This paper suggests a hybrid path planning method of multi-robots, where a path deviation prevention for maintaining a specific formation is implemented by using repulsive function, $A^*$ algorithm and UKF (Unscented Kalman Filter). The repulsive function in potential field method is used to avoid collision among robots and obstacles. $A^*$ algorithm helps the robots to find optimal path. In addition, error estimation based on UKF guarantees small path deviation of each robot during navigation. The simulation results show that the swarm robots with designated formation successfully avoid obstacles and return to the assigned formation effectively.

Path Planning of Mobile Robot using Weighted Potential Function with Obstacle Avoidance (가중화된 포텐셜 함수를 이용한 이동 로봇의 장애물 회피 경로 계획)

  • Kim, Jin-Hwan
    • The Transactions of the Korean Institute of Electrical Engineers P
    • /
    • v.58 no.1
    • /
    • pp.15-19
    • /
    • 2009
  • This paper presents the potential field for mobile robot path planning. The proposed repulsive potential has weighted parts, which consists of conventional repulsive potential and goals nonreachable with obstacles nearby repulsive potential. It ensures the global minimum of the total potential when the robot approaches goals near obstacle and the robot passes the adjacent obstacles. Simulation results shows that the proposed potential is better than conventional potentials.

A Modified Enskog-Like Equation of Self-Diffusion Coefficients for Penetrable-Sphere Model Fluids

  • Suh, Soong-Hyuck;Liu, Hong-Lai
    • Bulletin of the Korean Chemical Society
    • /
    • v.32 no.4
    • /
    • pp.1336-1340
    • /
    • 2011
  • Molecular dynamics simulations have been performed to investigate the transport properties of self-diffusion coefficients in the penetrable-sphere model system. The resulting simulation data for the product of the packing fraction and the self-diffusion coefficient exhibit a transition from an increasing function of density in lower repulsive systems, where the soft-type collisions are dominant, to a decreasing function in higher repulsive systems, where most particle collisions are the hard-type reflections due to the low-penetrability effects. A modified Enskog-like equation implemented by the effective packing fraction with the mean-field energy correction is also proposed, and this heuristic approximation yields a reasonably good result even in systems of high densities and high repulsive energy barriers.

Tactile feedback device using repulsive force of the magnets for teleoperation (자석의 반발력을 이용한 원격조종용 촉각궤환장치)

  • Ahn, Ihn-Seok;Moon, Yong-Mo;Lee, Jung-Hun;Park, Jong-Oh;Lee, Jong-Won;Woo, Kwang-Bang
    • Journal of Institute of Control, Robotics and Systems
    • /
    • v.3 no.1
    • /
    • pp.67-76
    • /
    • 1997
  • In this paper we developed a tactile feedback device using repulsive force of magnets. The force of the tactile feedback device was derived from the Maxwell's stress method by using the concept of magnetic charge. Magnetic repulsive force is linear function with respect to current and nonlinear to displacement. Experimental data shows these characteristics. To compensate the fact that the presented tactile feedback device can not be controlled by close loop control, we developed a simulation model which predicts output displacement and force by using Runge-Kutta method. And, this paper evaluated the presented tactile feedback device and compared it with commercial tactile feedback devices.

  • PDF

Impact Angle Control Guidance Synthesis for Evasive Maneuver against Intercept Missile

  • Yogaswara, Y.H.;Hong, Seong-Min;Tahk, Min-Jea;Shin, Hyo-Sang
    • International Journal of Aeronautical and Space Sciences
    • /
    • v.18 no.4
    • /
    • pp.719-728
    • /
    • 2017
  • This paper proposes a synthesis of new guidance law to generate an evasive maneuver against enemy's missile interception while considering its impact angle, acceleration, and field-of-view constraints. The first component of the synthesis is a new function of repulsive Artificial Potential Field to generate the evasive maneuver as a real-time dynamic obstacle avoidance. The terminal impact angle and terminal acceleration constraints compliance are based on Time-to-Go Polynomial Guidance as the second component. The last component is the Logarithmic Barrier Function to satisfy the field-of-view limitation constraint by compensating the excessive total acceleration command. These three components are synthesized into a new guidance law, which involves three design parameter gains. Parameter study and numerical simulations are delivered to demonstrate the performance of the proposed repulsive function and guidance law. Finally, the guidance law simulations effectively achieve the zero terminal miss distance, while satisfying an evasive maneuver against intercept missile, considering impact angle, acceleration, and field-of-view limitation constraints simultaneously.

Navigation Technique of Unmanned Vehicle Using Potential Field Method (포텐셜 필드 기법을 이용한 무인차량의 자율항법 개발)

  • Lee, Sang-Won;Moon, Young-Geun;Kim, Sung-Hyun;Lee, Min-Cheol
    • Transactions of the Korean Society of Automotive Engineers
    • /
    • v.19 no.4
    • /
    • pp.8-15
    • /
    • 2011
  • This paper proposes a real-time navigation algorithm which integrates the artificial potential field (APF) for an unmanned vehicle in the unknown environment. This approach uses repulsive potential function around the obstacles to force the vehicle away and an attractive potential function around the goal to attract the vehicle. In this research, laser range finder is used as range sensor. An obstacle detected by the sensor creates repulsive vector. Differential global positioning system (DGPS) and digital compass are used to measure the current vehicle position and orientation. The measured vehicle position is also used to create attractive vector. This paper proposes a new concept of potential field based navigation which controls unmanned vehicle's speed and steering. The magnitude of repulsive force based on the proposed algorithm is designed not to be over the magnitude of attractive force while the magnitude is increased linearly as being closer to obstacle. Consequently, the vehicle experiences a generalized force toward the negative gradient of the total potential. This force drives the vehicle downhill towards its goal configuration until the vehicle reaches minimum potential and it stops. The effectiveness of the proposed APF for unmanned vehicle is verified through simulation and experiment.

Dynamic Modeling and Repulsive Force Control of Medical Hpatic Master (의료용 햅틱 마스터의 동적 모델링과 힘 반향 제어)

  • Oh, Jong-Seok;Choi, Seung-Bok
    • Transactions of the Korean Society for Noise and Vibration Engineering
    • /
    • v.22 no.3
    • /
    • pp.284-290
    • /
    • 2012
  • In this research, a new type of haptic master device using electrorheological(ER) fluid for minimally invasive surgery(MIS) is devised and control performance of the proposed haptic master is evaluated. The proposed haptic master consists of ER bi-directional clutch/brake for 2 DOF rotational motion(X, Y) using gimbal structure and ER brake on the gripper for 1 DOF rotational motion (Z). Using Bingham characteristic of ER fluid and geometrical constraints, principal design variables of the haptic master are determined. Then, the generation of torque of the proposed master is experimentally evaluated as a function of applied field of voltage. A sliding mode controller which is robust to uncertainties is then designed and empirically realized. It has been demonstrated via experiment that the proposed haptic master associated with the controller can be effectively applied to MIS in real field conditions.