• Journal of Institute of Control, Robotics and Systems
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• v.21 no.11
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• pp.1064-1069
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• 2015

Control Moment Gyro (CMG) has been used as an indirect actuator of a single-wheel robot system GYROBO, developed at Chungnam National University. The flip motion of the gimbal system produces the gyroscopic motion onto the body system while the body motion also produces the gyroscopic motion onto the gimbal system inversely. In this paper, the intuitive equation of the inverse gyroscopic effect is derived as the direct relation between the rate of the body system and the rate of the gimbal system. Experiments on the inverse gyroscopic effect under the chaotically generated disturbance are conducted. Experimental data are approximated by a linear equation using the least square method.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.2
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• pp.335-341
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• 2016

In general, a yawing motion concept is used for the lateral control of one wheel robot where the gimbal system is located horizontally. In this paper, another concept of the vertically located gimbal system is presented for the same purpose. Although the vertical concept undergoes an instability more easily than the horizontal one, the pitching motion of the gyroscopic effect is considered. Firstly, the trade-off relation between two balancing concepts are investigated by comparing the gyroscopic mechanism. Secondly, the dynamic model for the problem of the proposed concept is derived using the oscillatory inverted stick model. Thirdly, the stability of the model is analyzed using the phase trajectory method. Finally, the control performance of the system by a vibration controller is simulated.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.16 no.3
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• pp.188-196
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• 2016

For the balancing control of a one-wheel mobile robot, CMG (Control Moment Gyro) can be used as a gyroscopic actuator. Balancing control has to be done in the roll angle direction by an induced gyroscopic motion. Since the dedicated CMG cannot produce the rolling motion of the body directly, the yawing motion with the help of the frictional reaction can be used. The dynamic uncertainties including the chattering of the control input, disturbances, and vibration during the flipping control of the high rotating flywheel, however, cause ill effect on the balancing performance and even lead to the instability of the system. Fuzzy compensation is introduced as an auxiliary control method to prevent the robot from the failure due to leaning aside of the flywheel. Simulation studies are conducted to see the feasibility of the proposed control method. In addition, experimental studies are conducted for the verification of the proposed control.

• Proceedings of the KIEE Conference
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• 2007.04a
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• pp.255-257
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• 2007

In this paper, we develop a single wheeled robot that has one wheel to move. The single wheel robot is similar to a rolling disk relying on gyroscopic motions to balance. The Gyrobo consists of three actuators: a spin motor, a tilt motor and a drive motor. The spin motor spins a flywheel at high rate so that it provides the balancing stability to upright the robot. The tilt motor controls steering of the robot by gyroscopic effect. The drive motor make forward accelerated motion to the robot. We have built and tested the Gyrobo to turn and move forward.

• Journal of Navigation and Port Research
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• v.30 no.9
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• pp.729-734
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• 2006

The authors aim to establish the theory necessary for developing the free gyroscopic compass and focus on mainly two points. One is to suggest north-finding principle by the angular velocity of the earth's rotation, and the other is to suggest orthogonal coordinate transformations of the motion rate of the spin axis, which transforms the components of motion rate in the free gyro frame into those in the platform frame and that this transformed rate is, in turn, transformed into the NED(north-east-down) navigation frame. Subsequently, ship's heading is obtained by using the fore-aft and athwartship components of the motion rate of the spin axis in the NED frame. In addition it was found how to solve the transformation matrix necessary for transforming each frame.

• 제어로봇시스템학회:학술대회논문집
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• 1986.10a
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• pp.251-255
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• 1986

Some missiles using canards as control device adopt rollerons to reduce roll motion due to aerodynamically induced rolling moment. This paper presents equations of motion of these missiles including the gyroscopic effect of rolleron rotors. Some linearized analysis results and simulation results are shown to coincide, thus some characteristic motions of missiles and rollerons can be seen.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.11a
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• pp.297-303
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• 2001

This research presents an analytical model to characterize the ball bearing vibration due to the waviness in a rigid rotor supported by multi-row ball bearings considering centrifugal force and gyroscopic moment of ball. The effects of centrifugal force and gyroscopic moment are introduced to the kinematic constraints and force equilibrium equations. The waviness of ball and races is modeled by the superposition of sinusoidal function and it is introduced to position vectors of race curvature center to use the Hertzian contact theory in order to calculate the elastic deflection and nonlinear contact force resulting from the waviness while the rotor has translational and angular motion. They can be determined by solving the nonlinear equations of motion with five degrees of freedom by using the Runge-Kutta-Fehlberg algorithm. The accuracy of this research is validated by comparing with the results of the prior researches. It characterizes the vibration frequencies resulting from the various kinds of waviness in rolling elements, the harmonic frequencies resulting from the nonlinear load-deflection characteristics of ball bearing resulting from the waviness interaction.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.44 no.4 s.316
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• pp.35-41
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• 2007

In this paper a single-wheeled robot called GYROBO is built and its hardware is implemented. The single-wheeled robot is similar to a rolling disk relying on gyroscopic motions to maintain its balance. The GYROBO consists of three actuators: a spin motor a tilt motor, and a drive motor. The spin motor spins a flywheel at a high rate so that it provides the balancing stability to upright the robot. The tilt motor controls steering of the robot by gyroscopic effect. The drive motor makes forward accelerated motion to the robot. Several models are designed. Experimental works of the GYROBO to turn and move forward have been presented.

• Journal of Sensor Science and Technology
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• v.28 no.1
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• pp.30-35
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• 2019

Inertial measurement units (IMUs) are widely used for wearable motion-capturing systems in the fields of biomechanics and robotics. When the IMUs are combined with optical motion sensors (hereafter, OPTs) for their complementary capabilities, it is necessary to align the coordinate system orientations between the IMU and OPT. In this study, we compare the application of two coordinate transformation-based orientation alignment methods between two coordinate systems. The first method (M1) applies angular velocity coordinate transformation, while the other method (M2) applies gyroscopic angle coordinate transformation. In M1 and M2, the angular velocities and angles, respectively, are acquired during random movement for a least-square algorithm to determine the alignment matrix between the two coordinate systems. The performance of each method is evaluated under various conditions according to the type of motion during measurement, number of data points, amount of noise, and the alignment matrix. The results show that M1 is free from drift errors, while drift errors are present in most cases where M2 is applied. Thus, this study indicates that M1 has a far superior performance than M2 for the alignment of IMU and OPT coordinate systems for motion analysis.

• Journal of the Earthquake Engineering Society of Korea
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• v.2 no.2
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• pp.1-12
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• 1998

The seismic behaviour of rotating machine-foundation systems subjected to six-component nonstationary earthquake ground accelerations is analyzed. The rotating machine-foundation system is idealized by using discs, rotating shaft, fluid-film journal bearings, pedestals, and space frame foundation. Thus, governing equations of motion for the rotating machine-foundation system are obtained by considering Gyroscopic effect, Coriolis effect, dynamic characteristics of fluid-film journal bearings, and translational and rotational motions of seismic rigid base. The influences due to Gyroscopic effects, Coriolis effects, and rotational motions of seismic base on the overall structural response are demonstrated by a numerical example. The results show that the inclusion of base rotations and Gyroscopic effects contributes significantly to the system response.