Fixed‐time cooperative control for robotic manipulators with motion constraints using unified transformation function

2021 ◽  
Author(s):  
Yang Liu ◽  
Huaguang Zhang ◽  
Yingchun Wang ◽  
Shuhang Yu
Keyword(s):  
Cooperative Control ◽  
Robotic Manipulators ◽  
Fixed Time ◽  
Transformation Function ◽  
Motion Constraints

scholarly journals Distributed fixed-time cooperative control of an islanded microgrid under event-triggered mechanism

2021 ◽  
Author(s):  
Deming Xu ◽  
Ze Li ◽  
Guozeng Cui ◽  
Wanjun Hao ◽  
Fuyuan Hu
Keyword(s):  
Cooperative Control ◽  
Fixed Time ◽  
Active Power ◽  
Settling Time ◽  
Power Sharing ◽  
Control Approach ◽  
Time Control ◽  
Islanded Microgrid ◽  
Control Protocols ◽  
Event Triggered

Abstract The secondary cooperative control problem of an islanded microgrid through event-triggered mechanism is investigated in this paper. A distributed fixedtime secondary cooperative control strategy is proposed to obtain frequency and voltage magnitude secondary restoration, and also a proportional active power sharing under an undirected topology. We consider a centralized event-triggered mechanism to alleviate the communication burden and reduce the frequency of controllers update. Through this mechanism, the distributed fixed-time control protocols using frequency, voltage magnitude and active power sampling measurement values of distributed generations (DGs) only when the predefined event-triggered condition is satisfied. Compared with the conventional distributed asymptotic control protocols under period-triggered communication, the secondary control objectives of an islanded microgrid are achieved within a fixed settling time by applying the presented distributed fixed-time control approach, and the upper bound of settling time is unrelated to any initial states. Meanwhile, the presented centralized event-triggered communication method exhibits excellent performance in alleviating communication burden and promoting control efficiency. The theoretical proof is given by adopting Lyapunov method. The simulation studies are conducted to illustrate the effectiveness of the proposed control scheme.

Fixed-time compliant motion/force control of robotic manipulators with environmental constraints

2017 ◽  
Vol 37 (3) ◽  
pp. 271-277 ◽  
Author(s):  
Chao Ma
Keyword(s):  
Control Strategy ◽  
Force Control ◽  
Stability Theory ◽  
Robotic Manipulators ◽  
Fixed Time ◽  
Lyapunov Theory ◽  
Environmental Constraints ◽  
Time Stability ◽  
Content Type ◽  
Compliant Motion

Purpose The purpose of this paper is to design a new compliant motion/force control strategy for robotic manipulators with environmental constraints in the sense of fixed-time stability. Design/methodology/approach This paper investigates a novel compliant motion/force control strategy for robotic manipulators with environmental constraints. By using the Lyapunov theory and fixed-time stability theory, a non-singular terminal sliding mode manifold is first established. Then, the compliant motion/force controller is designed, and relevant conditions are given for guaranteeing that the robotic manipulator can track the prescribed constrained trajectory while exerting a desired force to the environment in fixed-time. An illustrative example is presented to show the effectiveness of our proposed control strategy. Findings Based on fixed-time stability theory, the desired compliant motion/force controller for robotic manipulators with environmental constraints is developed. Originality/value Compared with most existing literature, the proposed fixed-time compliant motion/force control strategy can provide the upper bound of the settling time independent of the initial conditions in designing procedure and is more practical for the real-world applications.

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