• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 1989년도 한국자동제어학술회의논문집; Seoul, Korea; 27-28 Oct. 1989
• /
• pp.1085-1090
• /
• 1989

In this paper, an adaptive control method is presented to guarantee the ultimate boundedness of uncertain systems with partially known uncertainty bounds. This method, with a conventional linear compensator, is used to improve the performance of the trajectory tracking of a robotic manipulator with uncertainties. The proposed method is simulated under several different environments, and its performance is compared with the computed torque method. The simulation results show that the proposed method is well suited for high-performance operation of uncertain robotic systems.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 1993년도 한국자동제어학술회의논문집(국내학술편); Seoul National University, Seoul; 20-22 Oct. 1993
• /
• pp.889-894
• /
• 1993

This paper presents a robust adaptive control scheme based on the Lyapunov design for robot manipulators subjected to inertial parameter uncertainties and bounded torque disturbances. The scheme is a modified version of the adaptive computed torque method which adopts a dead zone into the adaptation mechanism so as to avoid parameter drifts by disturbances. It is shown via stability analysis and computer simulations that all the signals in the overall adaptive system are bounded and tracking errors lie within a prespecified bound.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 1993년도 한국자동제어학술회의논문집(국내학술편); Seoul National University, Seoul; 20-22 Oct. 1993
• /
• 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.

• 한국산업융합학회 논문집
• /
• 제19권4호
• /
• pp.206-215
• /
• 2016

Delta parallel robots are now widely used for high-speed applications. However, typical Delta robots, such as ABB Flexpicker suffer from rotating axis with passive prismatic joint subjected to critical speed and so requiring careful maintenance. In this paper, a novel 4-DOF high-speed parallel robot with four legs is presented, which consists of three legs with 90 degree arrangement for translational motions and one remaining leg with rack & pinion gears for rotational motion. The inverse kinematics, velocity, acceleration, statics, and inverse dynamics have been analyzed. From the workspace analysis and inverse dynamics simulation for 0.43 sec cycle time, the 4-axis parallel robot prototype with 12kg payload has been designed. In the future research, computed torque control methods will be developed for the prototype.

• 한국정밀공학회지
• /
• 제10권3호
• /
• pp.133-140
• /
• 1993

In this paper, we prpose a method for tracking optimally a spatial trajectory of the end-effector of flexible robot arms with multiple joints. The proposed method finds joint trajectories and joint torques necessary to produce the desired end-effector motion of flexible manipulator. In inverse kinematics, optimized joint trajectories are computed from elastic equations. In inverse dynamics, joint torques are obtained from the joint euqations by using the optimized joint trajectories. The equations of motion using finite element method and virtual work principle are employed. Optimal control is applied to optimize joint trajectories which are computed in inverse kinematics. The simulation result of a flexible planar manipulator is presented.

• 대한임베디드공학회논문지
• /
• 제3권2호
• /
• pp.49-56
• /
• 2008

This paper proposes a PC-based open architecture controller for a multi-axis robotic manipulator. The designed controller can be applied for various multi-axes robotic manipulators since the motion controller is implemented on a PC with its peripheral devices. The accuracy of the controller based on the computed torque method has been measured with the dynamic model of manipulator. Since the controller is implemented in the PC-based architecture, it is free from the user circumstances and the operating environment. Dynamics of the manipulator have been compensated by the feed forward path in the inner loop and the resulting linear outer loop has been controlled by PD algorithm. Using the specialized language, it can be more efficient in programming and in driving of the multi-axis robot. Unlike the conventional controller that is used to control only a specific robot, this controller can be easily changed for various types of robots. This paper proposes a PC-based controller that has a simple architecture with its simple interface circuits than general commercial controllers. The maintenance and the performance of the controller can be easily improved for a specific robot. In fact, using a Samsung multi-axis robot, AT1, the controller performance and convenience of the PC-based controller have been verified by comparing to the commercial one.

• 한국산업융합학회 논문집
• /
• 제21권2호
• /
• pp.53-62
• /
• 2018

This study propose a new approach to control the optimal working path of vertical type articulated robot with translation joint for trimming working process automation in forging manufacturing process. The basic structure of the proposed robotic joints controller consists of a Proportional-Intergral controller and a Proportional-Derivative controller in parallel. The proposed control scheme takes advantage of the properties of the fuzzy PID controllers. The proposed method is suitable to control of the trajectory and path control in cartesian space for vertical type articulated robot manipulator. The results illustrates that the proposed fuzzy computed torque controller is more stable and robust than the conventional computed torque controller. The reliability is varified by simulation test for vertical type s articulated robot with seven joints including one trqanslation joint.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 1988년도 한국자동제어학술회의논문집(국내학술편); 한국전력공사연수원, 서울; 21-22 Oct. 1988
• /
• pp.32-36
• /
• 1988

Generally, for nonlinear control of robotic system, the method of computed torque or inverse dynamics is frequently used. In this case, exact knowledge of the system parameters is required, however. This paper addresses the problem of nonlinear control when the parameter of system is varied. The approach is based upon decoupled model following. As an example, control of a three degree of freedom manipulator arm under mass variation is simulated.

• 대한전자공학회논문지
• /
• 제27권10호
• /
• pp.53-59
• /
• 1990

로보트 매니퓰레이터를 제어하는데 있어서, 토오크 계산법을 이용한 새로운 가변구조 모델 추종제어기를 설계한다. 슬라이딩 모드가 존재하기 위한 충부조건은 Lyapunov 함수에 의해 유도된다. 기준 모델은 이중 적분기를 사용하고 가속도 입력은 시스템의 안정성과 원하는 성능을 얻기 위하여 비례-미분 제어기로 구성한다. 제안된 제어기법은 매니퓰레이터 동력학 방정식 각 항들의 상한값과 추정값을 부여함으로써 정확한 매개변수의 지식과 역행렬 계산을 요구하지 않는다. 따라서 모의실험 결과 제어된 제어기가 목적궤적의 수렴성이 개선되었음을 보여준다.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 1992년도 한국자동제어학술회의논문집(국제학술편); KOEX, Seoul; 19-21 Oct. 1992
• /
• pp.1-6
• /
• 1992

A principle of "orthogonalization" is proposed as an extended notion of hybrid (force and position) control for robot manipulators under geometric endpoint constraints. The principle realizes the hybrid control in a strict sense by letting position and velocity feedback signals be orthogonal in joint space to the contact force vector whose components are exerted at corresponding joints. This orthogonalization is executed via a projection matrix computed in real-time from a gradient of the equation of the surface in joint coordinates and hence both projected position and velocity feedback signals become perpendicular to the force vector that is normal to the surface at the contact point in joint space. To show the important role of the principle in control of robot manipulators, three basic problems are analyzed, the first is a hybrid trajectory tracking problem by means of a "modified hybrid computed torque method", the second is a model-based adaptive control problem for robot manipulators under geometric endpoint constraints, and the third is an iterative learning control problem. It is shown that the passivity of residual error dynamics of robots follows from the orthogonalization principle and it plays a crucial role in convergence properties of both positional and force error signals.force error signals.