비선형력 보상 관절 별 로봇 제어

Abstract

로봇의 운동은 관절 상호 간의 운동이 연계되어 매우 복잡한 비선형 미분방정식으로 나타내어질 뿐 만 아니라 관절에서의 마찰력, 하중, 의외의 외력 등과 같이 운동 중 그 크기를 정확히 측정하기가 어려운 변수에 의하여도 그 식이 달라진다. 이들 변수의 변화에 기인한 힘들 때문에 선형제어기로는 로봇을 정확히 제어하기가 매우 어렵다. 따라서 본 연구에서는 이와 같은 힘을 보상할 수 있는 관절 별 보상 제어기를 개발하고 이의 안정성을 리아푸노프 이론을 이용하여 증명한다. 또한 일 관절 로봇을 대상으로 전산 모의 실험과 실제 실험으로 개발된 제어기의 성능과 안정성을 검증한다. 실험 결과 개발된 제어기의 궤적 추적 성능이 선형제어기인 비례-미분 제어기에 비하여 월등하였고 제어계도 안정함을 볼 수 있었다.

Robot manipulator dynamics are governed by a set of very complicated nonlinear and strongly coupled differential equations. The dynamics contain system parameters which can change with time and are difficult to measure accurately, such as joint friction, the payload, and unexpected external forces. The forces introduced by the parameters degrade the performance of controllers designed, especially the controllers designed based on linear control theory. Therefore, in this paper, a simple decentralized nonlinear force compensation controller for robot manipulators is proposed and the stability of the controller is proved by using Lyapunov theory. The performance and stability of the controller proposed is also verified by computer simulations and experiments. The results of the simulations and experiments with one link model show that the controller proposed is very superior in trajectory tracking of joint motion to a proportional and derivative controller, and also show excellent system stability.

Robot manipulator dynamics are governed by a set of very complicated nonlinear and strongly coupled differential equations. The dynamics contain system parameters which can change with time and are difficult to measure accurately, such as joint friction, the payload, and unexpected external forces. The forces introduced by the parameters degrade the performance of controllers designed, especially the controllers designed based on linear control theory. Therefore, in this paper, a simple decentralized nonlinear force compensation controller for robot manipulators is proposed and the stability of the controller is proved by using Lyapunov theory. The performance and stability of the controller proposed is also verified by computer simulations and experiments. The results of the simulations and experiments with one link model show that the controller proposed is very superior in trajectory tracking of joint motion to a proportional and derivative controller, and also show excellent system stability.