• Title, Summary, Keyword: Torque Redundancy

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Trajectory planning for redundant robot by joint disturbance torque minimization (여유자유도 로봇의 관절외란최소화를 이용한 궤적계획)

  • 최명환;최병진
    • 제어로봇시스템학회:학술대회논문집
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    • pp.1581-1584
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    • 1997
  • This paper poropsed an efficient optimization technuque to resolve redundancy and a trajectory planning for a high precision control using proposed optimization technique. The proposed techniqus is the joint disturbance torque optimizatioin considering redundancy in the joing servo control. Joint disturbance torque is not unknown it is described dynamic equation ignored friction and viscosity. The proposed technique is used the dynamic equatiion included the joint disturbance torque characteristics. Numerical example of 3 joint planar redundant robot manipulator is simulated. In the 2-norm minimization of joint disturbance torque we compared pseudoinverse local optimization with proposed technique, and the results showed better the proposed technique. So the proposed technique can be highly precision controlled redundant robot manipulators in the joint servo control.

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Redundancy Resolution by Minimization of Joint Disturbance Torque for Independent Joint Controlled Kinematically Redundant Manipulators

  • Park, Myoung-Hwan
    • Transactions on Control, Automation and Systems Engineering
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    • v.2 no.1
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    • pp.56-61
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    • 2000
  • Majority of industrial robots are controlled by a simple independent joint control of joint actuators rather than complex controllers based on the nonlinear dynamic model of the robot manipulator. In this independent joint control scheme, the performance of actuator control is influenced significantly by the joint disturbance torques including gravity, Coriolis and centrifugal torques, which result in the trajectory tracking error in the joint control system. The control performance of a redundant manipulator under independent joint control can be improved by minimizing this joint disturbance torque in resolving the kinematic redundancy. A 3 DOF planar robot is studied as an example, and the dynamic programming method is used to find the globally optimal joint trajectory that minimize the joint disturbance torque over the entire motion. The resulting solution is compared with the solution obtained by the conventional joint torque minimization, and it is shown that joint disturbance can be reduced using the kinematic redundancy.

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Control input reconstruction using redundancy under torque limit

  • Park, Jonghoon;Chung, Wan-Kyun;Youm, Youngil
    • 제어로봇시스템학회:학술대회논문집
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    • pp.452-455
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    • 1995
  • Various physical limitations which intrinsically exist in the manipulator control system, for example kinematic limits and torque limit, cause some undesirable effects. Specifically, when one or more actuators are saturated the expected control performance can not be anticipated and in some cases it induces instability of the system. The effect of torque limit, especially for redundant manipulators, is studied in this article, and an analytic method to reconstruct the control input using the redundancy is proposed based on the kinematically decomposed modeling of redundant manipulators. It results to no degradation of the output motion closed-loop dynamics at the cost of the least degradation of the null motion closed-loop dynamics. Numerical simulations help to verify the advantages of the proposed scheme.

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A Study on Impact Control of Planar Redundant Manipulator using A Intelligent Control (지능제어를 이용한 평면 여자유도 매니퓰레이터의 충돌제어에 관한 연구)

  • Yoo, Bong-Soo;Koo, Seong-Wan;Joh, Joong-Seon
    • Journal of the Korean Institute of Intelligent Systems
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    • v.18 no.6
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    • pp.787-796
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    • 2008
  • When the manipulator collides with surroundings, there occurs an impulse. To reduce the impulse, the self motion should maintain the manipulator's position by the minimally effective mass. At this time, we can use the local joint torque minimization algorithm to resolve the redundancy. In this study, to reduce the impulse and damages by the impact between the manipulator and surroundings, new control algorithm for the minimization of the joint torque using the kinetic redundancy and the impact minimization is proposed. It adapts fuzzy logic and genetic algorithm to the conventional local joint torque minimization algorithm. The proposed algorithm is applied to a 3-DOF redundant planar manipulator. Simulation results show that the proposed algorithm works well.

Force and Pose control for Anthropomorphic Robotic Hand with Redundancy (여유자유도를 가지는 인간형 로봇 손의 자세 및 힘 제어)

  • Yee, Gun Kyu;Kim, Yong Bum;Kim, Anna;Kang, Gitae;Choi, Hyouk Ryeol
    • The Journal of Korea Robotics Society
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    • v.10 no.4
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    • pp.179-185
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    • 2015
  • The versatility of a human hand is what the researchers eager to mimic. As one of the attempt, the redundant degree of freedom in the human hand is considered. However, in the force domain the redundant joint causes a control issue. To solve this problem, the force control method for a redundant robotic hand which is similar to the human is proposed. First, the redundancy of the human hand is analyzed. Then, to resolve the redundancy in force domain, the artificial minimum energy point is specified and the restoring force is used to control the configuration of the finger other than the force in a null space. Finally, the method is verified experimentally with a commercial robot hand, called Allegro Hand with a force/torque sensor.

Optimal Redundant Actuation of Parallel Manipulators with High Operational Stiffness (고강성 병렬형 로봇의 최적 여유 구동)

  • Kim, Sung-Bok
    • Journal of Institute of Control, Robotics and Systems
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    • v.6 no.2
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    • pp.181-189
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    • 2000
  • This paper presents the optimal redundant actuation of parallel manipulators for complicated robotic applications such as cutting grinding drilling and digging that require a high degree of operational stiffness as well as the balance between force applicability and dexterity. First by taking into account the distribution(number and location) of active joints the statics and the operational stiffness of a redundant parallel manipulator are formulated and the effects of actuation redundancy are analyzed, Second for given task requirements including joint torque limit task force maximum allowable disturbance and maximum allowable deflection the task execution conditions of a redundant parallel manipulator are derived and the efficient testing formulas are provided. Third to achieve high operational stiffness while maintaining moderate dexterity the redundant actuation of a parallel manipulator is optimized which determines the optimal distribution of active joints and the optimal internal joint torque, Finally the simulation results for the optimal redundant actuation of a planar parallel manipulator are given.

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Control of Redundant Manipulators Using Null-Space Dynamics (여유자유도 로보트 충격제어)

  • Kim, Il-Hwan
    • Journal of Industrial Technology
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    • v.15
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    • pp.63-70
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    • 1995
  • This paper presents an impact control algorithm for reducing the potentially damaging effects by interation of redundant manipulators with their environments. In the proposed control algorithm, the redundancy is resolved at the torque level by locally minimizing joint torque, subject to the operational space dynamic formulation which maps the joint torque set into the operational forces. For a given pre-impact velocity of the manipulator, the proposed approach is on generating joint space trajectories throughout the motion near the contact which instantaneously minimize the impulsive force which is a scalar function of manipulator's configurations. The comparative evaluation of the proposed algorithm with a local torque optimization algorithm with a local torque optimization algorithm without reducing impact is performed by computer simulation. The simulation results illustrate the effectiveness of the algorithm in reducing both the effects of impact and large torque requirements.

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Impact control of redundant manipulators using null-space dynamucs

  • Chung, W.J.;Choi, S.L.;kim, I.H.;Chung, G.J.
    • 제어로봇시스템학회:학술대회논문집
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    • pp.89-94
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    • 1994
  • This paper presents an impact control algorithm for reducing the potentially damaging effects by interation of redundant manipulators with their environments. In the. proposed control algorithm, the redundancy is resolved at the torque level by locally minimizing joint torque, subject to tire operational space dynamic formulation which maps tire joint torque set into the operational forces. For a given pre-impact velocity of the manipulator, the proposed approach is on generating joint space trajectories throughout the motion near the contact which instantaneously minimize the impulsive force which is a scalar function of manipulator's configurations. This is done by using the null space dynamics which does not affect the motion of an end-effector. The comparative evaluation of the proposed algorithm with a local torque optimization algorithm without reducing impact is performed by computer simulation. The simulation results illustrate the effectiveness of the algorithm in reducing both the effects of impact and large torque requirements.

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Dynamic control of redundant manipulators based on stbility condition

  • Chung, W.J.;Chung, W.K.;Youm, Y.
    • 제어로봇시스템학회:학술대회논문집
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    • pp.902-907
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    • 1993
  • An efficient dynamic control algorithm that outperforms existing local torque optimization techniques for redundant manipulators is presented. The method resolves redundancy at the acceleration level. In this method, a systematic switching technique as a trade-off means between local torque optimization and global stability is proposed based on the stability condition proposed by Maciejewski [1]. Comparative simulations on a three-link planar arm show the effectiveness of the proposed method.

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PMSM Torque Control Algorithm under One Phase Open-Fault in Three-Phase Inverter Condition (삼상 인버터의 한상 개방 고장 시 PMSM 토크제어 알고리즘)

  • Lee, Jin-Hwan;Lee, Jong-Min;Cho, Young-Pyo;Kwon, Chun-Ki;Yoo, Ji-Yoon
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.62 no.9
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    • pp.1249-1254
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    • 2013
  • A torque control algorithm suitable for detecting an open circuit failure in which one of the three phases is unable to supply power to a motor in the permanent magnet synchronous motor is presented in this paper. When the failure occurs in the inverter, the output torque of motor is restricted. A new method which is implemented by using only a processor algorithm internally without any hardware redundancy circuit is proposed. A simulation and experimental study is carried out with a three phase inverter system to show the validity of the proposed method.