Space robotics is regarded as one of the most impressing approaches for space debris removal missions. Due to the residual momentum of debris, it is essential to stabilize the base rapidly after capture. This paper pr...Space robotics is regarded as one of the most impressing approaches for space debris removal missions. Due to the residual momentum of debris, it is essential to stabilize the base rapidly after capture. This paper presents a novel control strategy for stabilization of a space robot in postcapture considering actuator failures and bounded torques. In the control strategy, the motion of the manipulator is not regarded as a disturbance to the base; in contrast, it is utilized to compensate for the limitation of the control torques by means of an inverse dynamical model of the system. Different scenarios where actuators are external mechanisms or momentum exchange devices have been carried out, and for actuator failures, both single-and two-actuator failures have been considered. Regarding to the performance of actuators, control torques are bounded. In cases that either single or two actuators have failed, the base can be stabilized kinematically when actuators are external mechanisms, but can only be stabilized dynamically when only momentum exchange devices are used. Finally, a space robot with a seven-degree-of-freedom manipulator in postcapture is studied to verify the validity and feasibility of the proposed control scheme. Simulation results show that the whole system can be stabilized rapidly.展开更多
This paper concerns the problem of output feedback tracking (OFT) control with bounded torque inputs of robot manipulators, and proposes a novel saturated OFT controller based on fuzzy self-tuning proportional and der...This paper concerns the problem of output feedback tracking (OFT) control with bounded torque inputs of robot manipulators, and proposes a novel saturated OFT controller based on fuzzy self-tuning proportional and derivative (PD) gains. First, aiming to accomplish the whole closed-loop control with only position measurements, a linear filter is involved to generate a pseudo velocity error signal. Second, different from previous strategies, the arctangent function with error-gain is applied to ensure the boundedness of the torque control input, and an explicit system stability proof is made by using the theory of singularly perturbed systems. Moreover, a fuzzy self-tuning PD regulator, which guarantees the continuous stability of the overall closed-loop system, is added to obtain an adaptive performance in tackling the disturbances during tracking control. Simulation showed that the proposed controller gains more satisfactory tracking results than the others, with a better dynamic response performance and stronger anti-disturbance capability.展开更多
基金co-supported by the National Natural Science Foundation of China (Nos. 11402200 and 11502203)the China Scholarship Council (CSC)
文摘Space robotics is regarded as one of the most impressing approaches for space debris removal missions. Due to the residual momentum of debris, it is essential to stabilize the base rapidly after capture. This paper presents a novel control strategy for stabilization of a space robot in postcapture considering actuator failures and bounded torques. In the control strategy, the motion of the manipulator is not regarded as a disturbance to the base; in contrast, it is utilized to compensate for the limitation of the control torques by means of an inverse dynamical model of the system. Different scenarios where actuators are external mechanisms or momentum exchange devices have been carried out, and for actuator failures, both single-and two-actuator failures have been considered. Regarding to the performance of actuators, control torques are bounded. In cases that either single or two actuators have failed, the base can be stabilized kinematically when actuators are external mechanisms, but can only be stabilized dynamically when only momentum exchange devices are used. Finally, a space robot with a seven-degree-of-freedom manipulator in postcapture is studied to verify the validity and feasibility of the proposed control scheme. Simulation results show that the whole system can be stabilized rapidly.
基金Project (No. 2008C21106) supported by the Science and Technology Foundation of Zhejiang Province, China
文摘This paper concerns the problem of output feedback tracking (OFT) control with bounded torque inputs of robot manipulators, and proposes a novel saturated OFT controller based on fuzzy self-tuning proportional and derivative (PD) gains. First, aiming to accomplish the whole closed-loop control with only position measurements, a linear filter is involved to generate a pseudo velocity error signal. Second, different from previous strategies, the arctangent function with error-gain is applied to ensure the boundedness of the torque control input, and an explicit system stability proof is made by using the theory of singularly perturbed systems. Moreover, a fuzzy self-tuning PD regulator, which guarantees the continuous stability of the overall closed-loop system, is added to obtain an adaptive performance in tackling the disturbances during tracking control. Simulation showed that the proposed controller gains more satisfactory tracking results than the others, with a better dynamic response performance and stronger anti-disturbance capability.
