• Journal of Institute of Control, Robotics and Systems
• /
• v.16 no.8
• /
• pp.771-779
• /
• 2010

This paper presents a method that integrates the geometric path tracking and the obstacle avoidance for nonholonomic mobile robot. The mobile robot follows the path by moving through the turning radius given from the pure pursuit method which is the one of the geometric path tracking methods. And the obstacle generates the obstacle potential, from this potential, the virtual force is obtained. Therefore, the turning radius for avoiding the obstacle is calculated by proportional to the virtual force. By integrating the turning radius for avoiding the obstacle and the turning radius for following the path, the mobile robot follows the path and avoids the obstacle simultaneously. The effectiveness of the proposed method is verified through the real experiments for path tracking only, static obstacle avoidance, dynamic obstacle avoidance.

• Proceedings of the KIEE Conference
• /
• 2005.10b
• /
• pp.415-417
• /
• 2005

This paper proposes tracking control method using pseudo-backstepping control for wheeled mobile robots with nonholonomic constraints. First, the pseudo commands for forward linear velocity and angular velocity are chosen based on the kinematics. Then, the actual torque control inputs are designed to make the actual forward linear velocity and angular velocity follow the pseudo commands. Both semi-global practical posture(position and heading direction angle) stabilization and trajectory tracking are achieved for reference trajectories such as straight line and sinusoidal curve. The stability and performance analysed and numerical simulations are performed to confirm the effectiveness of the proposed scheme.

• Journal of Power Electronics
• /
• v.13 no.6
• /
• pp.975-984
• /
• 2013

This paper proposes a robust optimal nonlinear control with an observer to reject the offset errors of position tracking for surface mounted permanent magnet synchronous motors. We provide the control method to reject offset errors and load torque for designing field oriented control (FOC) based the alternating current (AC) frame. The proposed method consists of a torque generator, a commutation scheme, an electrical controller, and a load torque observer. The mechanical controller is designed to compensate for load torque and the offset error and generate the desired torque. The commutation scheme is proposed to create the desired currents for the desired torque. The electrical controller is developed to guarantee the desired currents. The observer is designed to estimate both the velocity and the load torque. In order to obtain the robustness to parameter uncertainties and a gain tuning guide, the linear quadratic regulator method is applied to the proposed method. The closed-loop stability is proven. A detailed process for the FOC design and an analysis of the control methods based on the AC frame are presented. The performance of the proposed method was validated via experiments. The proposed method obtains the FOC based on the AC frame. Furthermore, the position tracking performance of the proposed method is superior to that of the conventional method.

• 제어로봇시스템학회:학술대회논문집
• /
• 1990.10b
• /
• pp.980-984
• /
• 1990

In order to find the optimal control law for the precise trajectory tracking of a robot manipulator, a perturbational control method is proposed based on a linearized manipulator dynamic model which can be obtained in a very compact and computationally efficient manner using the dual number algebra. Manipulator control can be decomposed into two parts: the nominal control and the corrective perturbational control. The nominal control is precomputed from the inverse dynamic model using the quantities of a desired trajectory. The perturbational control is obtained by applying the second-variational method on the linearized dynamic model. Simulation results for a PUMA-560 robot show that, by using this controller, the desired trajectory tracking performance of the robot can be achieved, even in the presence of large initial positional disturbances.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.63 no.6
• /
• pp.786-796
• /
• 2014

This paper presents a new approach to design a robust tracking controller for linear time-invariant systems with uncertain time-delay. By introducing the model following control (MFC) structure which consists of two loops in nature, we show that the controller is capable of having a predictive control action and effectively tracking the reference output with a desired transient response as well. Three design techniques to achieve good tracking performance are suggested. It is also analytically shown that the tracking performance of the proposed scheme is more robust than that of typical single-loop feedback structure. An illustrative example is given to compare the tracking performances of the proposed methods with a single loop method.

• Journal of Mechanical Science and Technology
• /
• v.20 no.5
• /
• pp.652-657
• /
• 2006

Although many methods about the control of irregular external noise have been introduced and implemented, it is still necessary to design a controller that will be more effective and efficient methods to exclude for various noises. Accumulation of errors due to model tracking, internal noises (thermal noise, shot noise and 1/f noise) that come from elements such as resistor, diode and transistor etc. in the circuit system and numerical errors due to digital process often destabilize the system and reduce the system performance. New stochastic controller is adopted to remove those noises using conventional controller simultaneously. Design method of a model tracking dual controller is proposed to improve the stability of system while removing external and internal noises. In the study, design process of the model tracking dual stochastic controller is introduced that improves system performance and guarantees robustness under irregular internal noises which can be created internally. The model tracking dual stochastic controller utilizing F-P-K stochastic control technique developed earlier is implemented to reveal its performance via simulation.

• 제어로봇시스템학회:학술대회논문집
• /
• 1993.10a
• /
• pp.1047-1051
• /
• 1993

A fuzzy controller of a manipulator with artificial rubber muscles is proposed. The fuzzy logic controller as a compensator is described to control the trajectory tracking of a -two link manipulator, where computed torque control method has already assumed to be applied. We shows that the fuzzy compensator with a simple adaptive scaling technique is effective for the robust control when there exist model uncertainties and/or untuned feedback gains. The effectiveness of the proposed control method is illustrated by some experimental results for a circular path tracking.

• Journal of the Korean Institute of Intelligent Systems
• /
• v.22 no.2
• /
• pp.198-204
• /
• 2012

Tracking and recognition of robots are required for the cooperation task of robots in various environments. In the paper, a tracking control system of moving robot using stereo image processing, code-book model and fuzzy controller is proposed. First, foreground and background images are separated by using code-book model method. A candidate region is selected based on the color information in the separated foreground image and real distance of the robot is estimated from matching process of depth image that is acquired through stereo image processing. The open and close processing of image are applied and labeling according to the size of mobile robot is used to recognize the moving robot effectively. A fuzzy tracking controller using distance information and mobile information by stereo image processing is designed for effective tracking according to the movement velocity of the target robot. The proposed fuzzy tracking control method is verified through tracking experiments of mobile robots with stereo camera.

• Journal of the Ergonomics Society of Korea
• /
• v.19 no.2
• /
• pp.47-61
• /
• 2000

To study the characteristic of the weight center control of humans, the tracking control capability of circular and wave motion by weight center movement was conducted by using the force platform. The control performance(the integrated value of the $|Object\;value(X)-Control\;Value(Y)|^{2}$) and control trace record was used to evaluate the individual performance characteristics. The size of the population for this study was 73, which consisted of engineering students, students majoring in taekwondo, students majoring in dance, all of which were in their twenties, and also people in their sixties. The results of this study indicate that the weight center control characteristics of humans can be represented by the evaluation method and values. People who were capable of tracking the object did not stop nor overshot the objective. In addition, habits or training characteristics and aging seemed to influence the performance of the subjects. In the future, development of different objectives for weight center control could be used to determine the severity of the disease of the subject and the effects of the treatment.

• Journal of Advanced Navigation Technology
• /
• v.7 no.2
• /
• pp.162-170
• /
• 2003

In this paper, we propose a robust controller for trajectory control of n-link robot manipulators using feature based on visual feedback. In order to reduce tracking error of the robot manipulator due to parametric uncertainties, integral action is included in the dynamic control part of the inner control loop. The desired trajectory for tracking is generated from feature extraction by the camera mounted on the end effector. The stability of the robust state feedback control system is shown by the Lyapunov method. Simulation and experimental results on a 5-link robot manipulator with two degree of freedom show that the proposed method has good tracking performance.