• Journal of the Korean Society of Physical Medicine
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• v.8 no.2
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• pp.209-217
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• 2013

PURPOSE: The purpose of this study was to investigate the clinical availability of the pendulum test (through reliability and validity) using a NK table attached electrogoniometer for spasticity measurement in patients with brain lesions. METHODS: Thirty-one stroke and traumatic brain injury subjects participated in the study. Intraclass correlation coefficient (ICC) was used to verify the test-retest reliability of spasticity measures of the pendulum test. Pearson's product correlation coefficient was used to examine the validity of the pendulum test through the amplitude of the deep tendon reflex (DTR) test known for objective and quantitative measure of spasticity. RESULTS: In these results, the test-retest reliability was showed significantly high correlation between pendulum tests (ICCs=.95~.97, p<.01). There were significant negative correlations between the amplitude of the DTR test and all measures of spasticity of the pendulum test(r=-.77~-.85, p<.01). CONCLUSION: Thus, it is possible to use the pendulum test using a NK table as an objective measure of spasticity, rather than other expensive equipment, which is more complicated to use. Further studies are needed to explore the therapeutic effects of spasticity using a newly designed pendulum test equipment in this study.

• Journal of The Korean Association For Science Education
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• v.26 no.5
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• pp.611-619
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• 2006

The aims of this study are to investigate science high school students' understanding of velocity and acceleration of a simple pendulum bob, and to investigate their understanding of inertia and gravitational force in the motion of a pendulum bob when the tension is removed. For the study, 46 students that had already studied the physical, concepts in simple pendulum were sampled from a science high school in a large city in Korea. For a comparison with general high school students' conceptions, 49 students were sampled from a general high school in the same city. The test tool for the investigation consisted of four drawing and simple-answering type questions developed by the authors. The outcomes of the study revealed that a substantial number of science high school students have misconceptions concerning acceleration in pendulum motion, and that many of them do not understand the relationship between force and acceleration. In addition, the results of the study showed that more than 30% of the students drew the path of a bob going along the tangential direction at the highest point of the motion, and approximately 20% of them drew the path of a bob falling straight down at the lowest point of the motion.

• Proceedings of the KIEE Conference
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• 1999.11c
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• pp.643-645
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• 1999

In experiment, a real inverted pendulum system has state constraints and limited amplitude of input. These problems make it difficult to design a swing-up controller. To overcome these problems, we design a sliding mode controller considering physical behaviour of the inverted pendulum system. This sliding mode controller uses a switching control action to converge along a specified path derived from energy equation from a state around the path to desired states(standing position). And optimal control method is used to guarantee stability at unstable equilibrium position. The designed controller can be applied to all inverted pendulum systems regardless of the values of their parameters. Compared with previous existing controllers, it is simple and easy to tune. Experimental results are given to show the effectiveness of this controller.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.7
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• pp.162-169
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• 2000

In this paper, we develop a parallel inverted pendulum system that has the characteristics of the strongly coupled dynamics of motion by an elastic spring, the time-variant system parameters, and inherent instability, and so on. Hence, it is possible to approximate some kinds of a physical system into this representative system and to apply the various control theories to this system in order to verie their fidelity and efficiency. For this purpose, an experimental system of the parallel inverted pendulum has been implemented, and a control scheme using the eigenstructure assignment for decoupling control is presented in comparison with the conventional LQR optimal control method. Furthermore, this system can be utilized as a testbed to develop and evaluate new control algorithms through various setups. Finally, in this paper, the results of the experiment are compared with those of numerical simulations for validation.

• Journal of Advanced Marine Engineering and Technology
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• v.36 no.8
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• pp.1104-1110
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• 2012

The inverted pendulum system is a common, interesting control problem that involves many basic elements of control theory. In the early, controls of stabilization for the inverted pendulum system were used classical methods like PD, PID controller. In recently, however, control methods based on modern and intelligent control theory are widely applied. The fuzzy logic controller which is often used in nonlinear control is a little too hard to design due to increasing fuzzy rules rapidly if the given system like inverted pendulum has many state variables. Also, in case the state variables are divided into two parts, two fuzzy controllers are needed in the control system. In this paper, the authors propose FCSC(Fuzzy Controller based on State variables Combination) that reorganized into two new signals depending on the physical meaning of the four state variables of the inverted pendulum system. The proposed method is applied to the inverted pendulum system and simulations are accomplished to illustrate the control performance.

• Journal of Advanced Marine Engineering and Technology
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• v.31 no.4
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• pp.462-467
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• 2007

The design and synthesis of a state feedback controller assumes the feedback of all state variables of the system. However, some state variables are not physical quantifies so that sensors may not be available, or may be too expensive to measure. Hence, a state observer can be an alternative to estimate unmeasurable state variables. This paper therefore presents a scheme for state observer-based stabilization control of inverted pendulum systems. The feedback gain matrices of both the state feedback controller and the state observer are tuned by real-coded genetic algorithms(RCGAs) such that the given performance indices are minimized. The proposed method is demonstrated through simulations.

• Journal of the Korean Institute of Intelligent Systems
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• v.26 no.2
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• pp.127-134
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• 2016

This paper presents a robust control of a reaction wheel inverted pendulum. To this end, a mathematical model is derived using physical laws, and then parameters in the model are identified as well. Based on the model, a robust position control is designed, which consists of two parts: swing-up control using passivity and robust stabilization control using LMI (Linear Matrix Inequality). When the pendulum starts to move, the swing-up control is applied. If the position of the pendulum is near the desired upright position, the control is switched to the robust stabilization control. This robust control is employed in order to deal with the uncertainties in the inertia of the pendulum dynamics. The performance of the proposed control scheme is validated not only simulation but also real experiment.

• The Journal of Korea Robotics Society
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• v.6 no.2
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• pp.108-117
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• 2011

This paper proposes an optimal ARS control of a two-wheel mobile inverted pendulum robot. Conventional researches are highly concentrated on the robust control of a mobile inverted pendulum on the flat ground, $i.e.$, mostly focus on the compensation of gyroscope signals. This newly proposed algorithm deals with a climbing control of a slanted surface based on the dynamic modeling using the conventional structure. During the climbing control of the robot, unexpected disturbance forces are essentially caused by the irregular contact force which comes from the irregular contact angle between the wheel and the terrain. The disturbances have effects on the optimal posture of the mobile robot to compensate the slanted angle. Therefore the dynamics equations through physical interpretation are derived for the selection of optimum climbing posture through ARS. Also using the ultrasonic sensor the slope information is obtained to compensate for the force of gravity. The control inputs are dynamically adjusted to climb up the slanted surface effectively. The proposed algorithm is demonstrated through the real experiments.

• Physical Therapy Korea
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• v.14 no.4
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• pp.7-13
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• 2007

The purpose of this study was to investigate correlations among objective measurements of spasticity in patients with brain lesions. Thirty-two stroke and traumatic brain injury subjects participated in the study. Spasticity was quantified using the knee first flexion angle, relaxation index obtained from a pendulum drop test, and the amplitude of a knee tendon reflex test. Pearson's product correlation coefficient was used to examine relationships among these measurements of spasticity. There was a significant positive correlation between the relaxation index and knee first flexion angle in patients with brain lesions (r=.895, p<.01). There was also significant negative correlation between the amplitude of knee tendon reflex and relaxation index (r=-.612, p<.01), and between amplitude and knee first flexion angle (r=-.537, p<.01). Thus, it is possible to use the knee first flexion angle as an objective measure of spasticity, rather than relaxation index, which is more complicated to obtain. Further studies are needed to explore the effects of functional improvement and long-lasting carryover effects of spasticity using a simple objective measure such as the knee first flexion angle from a pendulum test.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 2012.05a
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• pp.57-58
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• 2012