• Journal of Institute of Control, Robotics and Systems
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• v.19 no.1
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• pp.1-9
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• 2013

This paper presents a new control algorithm for dynamic control of a unicycle robot. The unicycle robot motion consists of a pitch that is controlled by an in-wheel motor and a roll that is controlled by a reaction wheel pendulum. The unicycle robot doesn't have any actuator for a yaw axis control, which makes the derivation of the dynamics relatively simple. The Euler-Lagrange equation is applied to derive the dynamic equations of the unicycle robot to implement the dynamic speed control of the unicycle robot. To achieve the real time speed control of the unicycle robot, the sliding mode control and LQ regulator are utilized to guarantee the stability while maintaining the desired speed tracking performance. In the roll controller, the sigmoid-function based sliding mode controller has been adopted to minimize the chattering by the switching function. The LQR controller has been implemented for the pitch control to drive the unicycle robot to follow the desired velocity trajectory in real time using the state variables of pitch angle, angular velocity, angle and angular velocity of the wheel. The control performance of the two control systems form a single dynamic model has been demonstrated by the real experiments.

• Journal of Institute of Control, Robotics and Systems
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• v.15 no.11
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• pp.1130-1136
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• 2009

A new control algorithm for the yaw motion control of a unicycle robot has been proposed in this paper. With the increase of life quality, there are various transportation systems such as segway and unicycle robot which provide not only transportation but also amusement. In most of the unicycle robots share the same technology in that the directions of roll and pitch are controlled by the balance controllers, allowing the robots to maintain balance for a long period by continuously moving forward and backward. However, one disadvantage of this technology is that it cannot provide the capability to the robots to avoid obstacles in their path way. This research focuses to provide the yawing function to the unicycle robot and to control the yaw motion to avoid the obstacles as desired. For the control of yawing motion, the yaw angle is adjusted to the inertia generated by the velocity and torque of a yawing motor which is installed in the center axes of the unicycle robot to keep the lateral control simple. Through the real experiments, the effective and robustness of the yawing control algorithm has been demonstrated.

• Journal of Institute of Control, Robotics and Systems
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• v.16 no.11
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• pp.1074-1081
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• 2010

Today, the research related to the robot is achieved in various part. With the high interest in means of transport, various researches about autonomous mobile robot and next generation transport is continuing. The unicycle robot among these needs much control technique like balance control model and driving model. For autonomous driving of this unicycle robot, from the basic balance control to direction switching control and velocity control are needed. But the environment elements like a gradient and frictional force or unbalanced elements from the structural feature. The unicycle needs the real time balance control so more complex, harder to control. And when functional addition is made, the problem that fall entire reaction velocity or accuracy would be happen. This paper introduces entire dynamics modeling of the unicycle robot and reduced model. And propose the new balance control algorithm using fuzzy controller. Also the evaluation about performance would be made through the test.

• Journal of Institute of Control, Robotics and Systems
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• v.18 no.3
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• pp.275-284
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• 2012

This paper proposes an attitude and direction control of a single wheel balanced robot. A unicycle robot is controlled by two independent control laws: the mobile inverted pendulum control method for pitch axis and the reaction wheel pendulum control method for roll axis. It is assumed that both roll dynamics and pitch dynamics are decoupled. Therefore the roll and pitch dynamics are obtained independently considering the interaction as disturbances to each other. Each control law is implemented by a controller separately. The unicycle robot has two DC motors to drive the disk for roll and to drive the wheel for pitch. Since there is no force to change the yaw direction, the present paper proposes a method for changing the yaw direction. The angle data are obtained by a fusion of a gyro sensor and an accelerometer. Experimental results show the performance of the controller and verify the effectiveness of the proposed control algorithm.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.1
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• pp.139-144
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• 2014

This paper presents the novel design, implementation and control of a single-wheel mobile robot that can balance by using air power from ducted fans. All of the motions of the single-wheel mobile robot are actuated by air power instead of motor torques. Using air power allows to reduce the total weight of the robot. The complementary sensor fusion algorithm is introduced to estimate the angle correctly. After several design and development, the robot is tested for balancing in the roll direction and yawing motion. In addition, the balancing control of the robot on a single rope is tested to evaluate the control performance.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.7
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• pp.799-807
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• 2014

This paper describes the development of an indoor locomotion assistive robot, Ball-Chair, comprising a novel drive system. This robot facilitates locomotion assistive operation in narrow spaces, in which common wheelchairs cannot move easily. The Ball-Chair has two main features: its structural feature and driving mechanism. The exoskeleton frames of the Ball-Chair have been designed with octagonal shapes resembling a circle, for minimizing its volume and weight. Additionally, all its driving parts (including the ball) are mounted within of the robot to enhance its safety. The Ball-Chair features a reverse ball-mouse driving mechanism comprising two driving omni-wheels in the x- and y-axes. By controlling the speed of each omni-wheel, a holonomic driving system that can facilitate omnidirectional locomotion has been achieved using only two wheels. The effective movement of the Ball-Chair in any direction within narrow indoor spaces was experimentally verified. The paper outlines the development procedure in detail.