Tip Of Robot Arm Research Articles

Equilibrium Control of Robot Arm Tip Mounted on a Transfer Coaxial Two-Wheel Robot

Japan has continued to experience population decline which adversely affect working-age group (15-64 years). As a remedy to this social issue, advancements in robotics and human-machine cooperation is proposed to make up for the declining labor force. To this end, design of robots which can work in constrained (indoor) workspace is desirable. A coaxial two-wheeled robot with an appended robot arm aimed at transporting objects is proposed in this paper. The robot is designed with center of gravity below the axle to make it statically stable at rest. It is combined with a robot arm with two links, two degrees of freedom. The goal is to maintain equilibrium of the arm tip during motion with the robot-arm is inclined at 0-, 3-, and 120-degree. In this study, simulations to combine a stable coaxial two-wheel robot with the robot arm is performed to confirm the effectiveness of the designed LQ, and LQI controller. From the results, all the controllers are able to maintain the robot-arm tip at 0-degrees. For 120-degrees, LQI performs better than LQ controller in stabilizing the rotation speed of the wheels by 1.7 seconds. In the future, the proposed controller model will be incorporated in the actual robot to confirm the performance for object transportation.

Design and Analysis of Jittering Mitigator for Robot Arm-Tip

To tackle the jittering of a robot arm-tip, a novel method of the jittering mitigation is proposed. The key idea is to transmit the jittering to vibration of a mass block nested inside the jittering-mitigator. This method only requires the frequency of the jittering at the arm-tip. To verify the practicability of the method, a practical robot was applied through simulations and physical experiments. The jittering mitigator device can be directly attached to or detached from the arm-tip. The jittering at the arm-tip was first measured through experiments using accelerometers connected to the vibration and noise testing system. Then, the dominant frequency was identified through fast Fourier transform analysis. The theoretical parameters of the jittering mitigator were calculated accordingly. A model was established to simulate the jitter reduction effect of the mitigator. The results revealed a 68% reduction in the average amplitude of the jittering vibration at the arm-tip, which is corroborated by the experiment results. The proposed method could be applicable to all types of robots theoretically because it only requires computing the frequency of jitter.

G1510304 ロボットアームによるヨーヨーのフォワードパス操作実現を目指したモデリングと制御([G151-03]ロボティクス・メカトロニクス部門一般セッション(3))

This study focuses on a yoyo operation called forward-pass trick by a robot arm as a part of approach to skill-full robots realizing human dexterity. Realization of forward-pass trick by the robot arm requires taking swing of the yoyo string into account. Hence a mathematical model including yoyo string swing is derived. The integrated model of the yoyo and the robot arms is also derived by Projection Method, and is used for design and calculation of the desired trajectory for the robot arm tip to follow it for throwing the yoyo. A PID-based servo controller is implemented to let the robot arm follow the trajectory. A robot arm is developed as the experimental system, and is used for verifycation of the proposed control system realizing the forward-pass trick.

Accurate Calibration of Kinematic Parameters of a Robot Using a Laser Tracking System : Compensation of Non-Geometric Errors Using Neural Networks and Selection of Optimal Measuring Points Using Genetic Algorithm

A laser tracking system is employed for measuring the robot arm's tip with high accuracy. The geometric parameters in the robot kinematic model are calibrated by minimizing errors between the measured positions and the predicted ones based on the model. The residual errors caused by non-geometric parameters are further reduced by using neural networks, realizing the high positioning accuracy of sub-millimeter order. To speed up the calibration process, the smaller number of measuring points is preferable. Optimal measuring points, which realize high positioning accuracy with small point number, are selected using genetic algorithm (GA).

1001 ロボットカメラ画像の処理によるカメラ位置算出の計算

In this research, as the compensation method of the robot positioning error, reference markers are photographed with the CCD camera attached at the tip of robot arm, and it aims at computing the correction value of a robot parameter based on a robot's present position computed using the analysis value of the picture. This paper reports the basic experiments that photographed the reference markers of position known with the CCD camera, and calculation of the camera position that applies the principle of photo survey.

ジャイロを用いたロボットの姿勢計測に関する研究 第２報 レーザトラッキングシステムとジャイロを併用したロボットの位置・姿勢キャリブレーション手法の提案

For the purpose of realizing not only positioning but also orientating accuracy of a robot, a position and orientation calibration method is newly proposed and applied to a 6-DOF articulated robot (PUMA 560). The existence of gear transmission errors and gear backlashes of the 4-6th axes of this robot is detected by using a high precision gyroscope and it is proved that these non-geometric errors cause the orientation error of robot arm's tip. A position and orientation measuring system using both a laser tracking system and this gyroscope is proposed. A calibration method, which uses both position and orientation data and considers non-geometric errors of 4-6th axes as parameters to be calibrated in the forward kinematics model, is proposed. The positioning accuracy of 0.2mm and roll, pitch, yaw orientating accuracy of (0.17°, 0.10°, 0.10°), which is near the limit value of calibration predicted by the orientating repeatability, are successfully achieved and it is experimentally proved that the proposed measuring system and the calibration method are very effective for improving the orientating accuracy while keeping the high positioning accuracy. The optimal weights of position and orientation data in the least squares estimation process of parameters are also discussed.

Analog data transmission through plastic optical fiber in robot with compensation of errors caused by optical fiber bending loss

A new type of analog data transmission system using a plastic fiber is proposed, where a direct intensity modulation scheme has been employed together with a differential amplifier to compensate for the transmission error caused by the optical fiber bending loss. This system was experimentally applied to transmit analog data of dimensions detected by the displacement sensor attached to the robot arm tip to the robot basement through the plastic optical fiber installed in the robot arm body.

2917 ピストンリング用ユニバーサル把持機構の接触問題構造解析

As the part of universal gripper development which holds piston ring of various diameters in 6 nails, the deformation behavior of piston ring in robot arm tip holding part was clarified, and adaptability evaluation of the hold mechanism was carried out. The aspect of the deformation in concretely holding piston ring in multiple supporting point was analyzed by the finite element method, and the relationship between deformation characteristic and retention force and hold method was clarified. On the basis of these analytical result, whether it was effective for the piston automatic insertion to the cylinder in respect of the deformation without the irrational in piston ring was investigated, and development support of the multiproducts-correspondent hold mechanism was carried out what kind of hold mechanism.