• Title, Summary, Keyword: balancing order

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APPROXIMATION AND BALANCING ORDERS FOR TOTALLY INTERPOLATING BIORTHOGONAL MULTIWAVELET SYSTEMS

  • Choi, Young-Woo;Jung, Jae-Won
    • Bulletin of the Korean Mathematical Society
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    • v.48 no.6
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    • pp.1157-1167
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    • 2011
  • We consider totally interpolating biorthogonal multiwavelet systems with finite impulse response two-band multifilter banks, a study balancing order conditions of such systems. Based on FIR and interpolating properties, we show that approximation order condition is completely equivalent to balancing order condition. Consequently, a prefiltering can be avoided if a totally interpolating biorthogonal multiwavelet system satisfies suitable approximation order conditions. An example with approximation order 4 is provided to illustrate the result.

A study on the generation of balancing trajectory for biped robot using genetic algorithm (유전 알고리즘을 이용한 이족보행로봇의 균형 궤적 생성에 관한 연구)

  • Kim, Jong-Tae;Kim, Jin-Geol
    • Journal of Institute of Control, Robotics and Systems
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    • v.5 no.8
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    • pp.969-976
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    • 1999
  • This paper is concerned with the generation of a balancing trajectory for improving the walking performance. The balancing motion has been determined by solving a second -order differential equation. However, this method caused some difficulties in linearizing and approximating the equation and had restrictions on using various balancing trajectories. The proposed difficulties in linearizing and approximating the equation and had restrictions on using various balancing trajectories. The proposed method i this paper is based on the genetic algorithm for minimizing the motins of balancing joints, whose trajectories are generated by the fifth-order polynomial interpolation after planning leg trajectories. The real walking experiments are made on the biped robot IWR-III, developed by our Automatic Control Laboratory. The system has 8 degrees of freedom and the structure of three pitches in each leg, and one roll and one prismatic joint in the balancing joints. The experimental result shows the validity and applicability of the new proposed algorithm.

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Active Voltage-balancing Control Methods for the Floating Capacitors and DC-link Capacitors of Five-level Active Neutral-Point-Clamped Converter

  • Li, Junjie;Jiang, Jianguo
    • Journal of Power Electronics
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    • v.17 no.3
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    • pp.653-663
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    • 2017
  • Multilevel active neutral-point-clamped (ANPC) converter combines the advantages of three-level ANPC converter and multilevel flying capacitor (FC) converter. However, multilevel ANPC converter often suffers from capacitor voltage balancing problems. In order to solve the capacitor voltage balancing problems for five-level ANPC converter, phase-shifted pulse width modulation (PS-PWM) is used, which generally provides natural voltage balancing ability. However, the natural voltage balancing ability depends on the load conditions and converter parameters. In order to eliminate voltage deviations under steady-state and dynamic conditions, the active voltage-balancing control (AVBC) methods of floating capacitors and dc-link capacitors based on PS-PWM are proposed. First, the neutral-point current is regulated to balance the neutral-point voltage by injecting zero-sequence voltage. After that, the duty cycles of the redundant switch combinations are adjusted to balance the floating-capacitor voltages by introducing moderating variables for each of the phases. Finally, the effectiveness of the proposed AVBC methods is verified by experimental results.

A Smooth Trajectory Generation for an Inverted Pendulum Type Biped Robot (도립진자형 이족보행로봇의 유연한 궤적 생성)

  • Noh Kyung-Kon;Kong Jung-Shik;Kim Jin-Geol;Kang Chan-Soo
    • Journal of the Korean Society for Precision Engineering
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    • v.22 no.7
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    • pp.112-121
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    • 2005
  • This paper is concerned with smooth trajectory generation of biped robot which has inverted pendulum type balancing weight. Genetic algorithm is used to generate the trajectory of the leg and balancing weight. Balancing trajectory can be determined by solving the second order differential equation under the condition that the reference ZMP (Zero moment point) is settled. Reference ZMP effect on gait pattern absolutely but the problem is how to determine the reference ZMP. Genetic algorithm can find optimal solution under the high order nonlinear situation. Optimal trajectory is generated when use genetic algorithm which has some genes and a fitness function. In this paper, minimization of balancing joints motion is used for the fitness function and set the weight factor of the two balancing joints at the fitness function. Inverted pendulum type balancing weight is very similar with human and this model can be used fur humanoid robot. Simulation results show ZMP trajectory and the walking experiment made on the real biped robot IWR-IV.

Control of balancing weight for IWR biped robot by genetic algorithm (유전 알고리즘을 이용한 IWR 이족 보행 로보트의 균형추 제어)

  • 심경흠;이보희;김진걸
    • 제어로봇시스템학회:학술대회논문집
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    • pp.1185-1188
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    • 1996
  • In this paper we present a genetic approach for trajectory control algorithm of balancing weight for IWR biped walking robot. The biped walking robot, IWR that was made by Automatic Control Lab. of Inha University has a trunk which stabilizes its walking by generating compensation moment. Trunk is composed of a revolute and a prismatic joint which roles balancing weight. The motion of balancing weight is determined by the gait of legs and represented by two linear second order ordinary differential equations. The solution of this equation must satisfy some constraints simultaneously to have a physical meaning. Genetic algorithm search for this feasible motion of balancing weight under some constraints. Simulation results show that feasible motion of balancing weight can be obtained by genetic algorithm.

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A Control of Balancing Robot (밸런싱 로봇 제어)

  • Min, Hyung-Gi;Kim, Ji-Hoon;Yoon, Ju-Han;Jeung, Eun-Tae;Kwon, Sung-Ha
    • Journal of Institute of Control, Robotics and Systems
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    • v.16 no.12
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    • pp.1201-1207
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    • 2010
  • This paper shows to stabilize a balancing robot. We derive the dynamics of a balancing robot and design its controller using LQR method. For stabilizing balancing robot, we introduce a method to detect an angle using inertial sensors. In this study, we use a complementary filter to fuse signals by frequency response of gyroscope and accelerometer in order to measure the inclined angle of balancing robot. The filter coefficients are obtained by least square to minimize error in angle-detecting filter design. And then, after we derive a dynamics of balancing robot using Lagrange method, we linearize that dynamics for using LQR method.

On-line Balancing of a Ultra-high speed Rotor with Residual Unbalance (자기베어링을 이용한 잔류질량불균형이 존재하는 초고속 회전체의 온라인 밸런싱)

  • 송상호
    • Journal of The Korean Society of Manufacturing Technology Engineers
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    • v.7 no.1
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    • pp.51-57
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    • 1998
  • In order to minimize vibration problems of rotating machinery rotors have been assembled through balancing machines. Since perfect balancing is impossible, residual unbalances cause serious vibration while the rotor is in high speed region. To minimize unbalance effects of magnetic bearing systems (AMB) during rotation on-line balancing methodology was studied. Unbalances were considered as disturbances of the system. The disturbance observer was used to estimate unbalance force from measurable state and input variables. Balancing inputs computed according to LQR and outputs of the observer were applied to eliminate unbalances during high speed rotation of the AMB. the effectiveness of the on-line balancing was verified through numerical simulations.

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Development of 3-Dimensional Simulator for a Biped Robot (이족 보행로봇의 3차원 모의실험기 개발)

  • Noh, Kyung-Kon;Kim, Jin-Geol;Huh, Uk-Youl
    • Proceedings of the KIEE Conference
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    • pp.2438-2440
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    • 2004
  • This study is concerned with development of 3-Dimensional simulator of a biped robot that has a prismatic balancing weight or a revolute balancing weight. The dynamic stability equation of a biped robot which have a prismatic balancing weight is conditional linear but a walking robot's stability equation with a revolute balancing weight is nonlinear. To get a stable gait of a biped robot, stabilization equations with ZMP (Zero Moment Point) are modeled as non-homogeneous second order differential equations for each balancing weight type. A trajectory of balancing weight can be directly calculated with the FDM (Finite Difference Method) solution of the linearized differential equation. In this paper, the 3-Dimensional graphic simulator is programmed to get and calculate the desired ZMP and the actual ZMP. Walking of 4 steps was simulated and verified. This balancing system will be applied to a biped humanoid robot, which consist Begs and upper body, at future work.

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Expanding the MCS of Refinery Process Compressor through Operating-Speed Balancing at 10,500 rpm (정유공정 압축기의 10,500 rpm 운전속도 밸런싱을 통한 MCS의 확장)

  • Lee, An-Sung;Kim, Byung-Ok
    • The KSFM Journal of Fluid Machinery
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    • v.12 no.6
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    • pp.41-46
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    • 2009
  • This paper deals with the operating-speed (high-speed) balancing of a refinery gasoline HDS (hydrodesulfurization) process recycle-gas 8-stages compressor rotor. A low-speed balancing condition of the rotor was measured as maintaining the G2.5 level. But an inspection run of operating-speed balancing condition, using tilting-pad journal bearings of actual use, showed that while it could be continuously-operated safely at a rated speed of 10,500 rpm, the rotor would not be able to run over 11,000 rpm as the vibration increased very sharply, approaching 11,000 rpm. In order to cure that a series of operating-speed balancing, which first calculated balance correction-weights by applying the influence coefficient measured and calculated at 10,500 rpm and then implemented correction works, was carried-out. The final operating-speed balancing results showed that the vibrations at the bearing pedestals represented very good levels of 0.2 mm/s by decreasing to as much as the 1/10 of the original vibrations and particularly, even at a targeted maximum continuous operating speed, MCS, of 11,500 rpm the vibrations represented about 1 mm/s, which is the operating-speed balancing vibration specification of API. Therefore, the expansion of MCS was successfully accomplished through the operating-speed balancing.

A Stability Analysis of a Biped Walking Robot about Balancing Weight (이족 보행로봇의 균형추 형태에 따른 안정성 해석)

  • Noh Kyung-Kon;Kim Jin-Geol
    • Journal of the Korean Society for Precision Engineering
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    • v.22 no.1
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    • pp.89-96
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    • 2005
  • This paper is concerned with a balancing motion formulation and control of the ZMP (Zero Moment Point) for a biped-walking robot that has a prismatic balancing weight or a revolute balancing weight. The dynamic stability equation of a walking robot which have a prismatic balancing weight is conditionally linear but a walking robot's stability equation with a revolute balancing weight is nonlinear. For a stable gait, stabilization equations of a biped-walking robot are modeled as non-homogeneous second order differential equations for each balancing weight type, and a trajectory of balancing weight can be directly calculated with the FDM (Finite Difference Method) solution of the linearized differential equation. In this paper, the 3dimensional graphic simulator is developed to get and calculate the desired ZMP and the actual ZMP. The operating program is developed for a real biped-walking robot IWRⅢ. Walking of 4 steps will be simulated and experimented with a real biped-walking robot. This balancing system will be applied to a biped humanoid robot, which consist legs and upper body, as a future work.