Continuous time-varying feedback control of a robotic manipulator with base vibration and load uncertainty

2020 ◽  
pp. 107754632092759
Author(s):  
Xi Wang ◽  
Baolin Hou

To solve precise and fast position control of a robotic manipulator with base vibration and load uncertainty, a continuous time-varying feedback control method based on the implicit Lyapunov function is studied. This method is proportional–derivative-like in the form of control law, but its proportional and differential coefficients depend on the system Lyapunov function, which are differentiable functions of system error variables. In the motion process of the robotic manipulator, the system performance is influenced by three main nonlinear factors: system friction, balance torque, and base vibration. As the former two factors are available to be modeled and identified through experiments, compensation of the two terms is added to the proposed control law to reduce the effects of system nonlinearities to a certain extent. Experimental results show that the proposed control strategy is robust to base vibration and load uncertainty. Besides, the compensation of system friction and balance torque can shorten the positioning time by 27.3%, from 1.32 s to 0.96 s. Meanwhile, the positioning precision is guaranteed, which verifies the effectiveness of the proposed control scheme.

2020 ◽  
Vol 42 (14) ◽  
pp. 2822-2829
Author(s):  
Kexin Xu ◽  
Xianqing Wu ◽  
Miao Ma ◽  
Yibo Zhang

In this paper, we consider the control issues of the two-dimensional translational oscillator with rotational actuator (2DTORA) system, which has two translational carts and one rotational rotor. An output feedback controller for the 2DTORA system is proposed, which can prevent the unwinding behaviour. In addition, the velocity signal unavailability and actuator saturation are taken into account, simultaneously. In particular, the dynamics of the 2DTORA system are given first. On the basis of the passivity and control objectives of the 2DTORA system, an elaborate Lyapunov function is constructed. Then, based on the introduced Lyapunov function, a novel output feedback control method is proposed straightforwardly for the 2DTORA system. Lyapunov theory and LaSalle’s invariance principle are utilized to analyse the stability of the closed-loop system and the convergence of the states. Finally, simulation results are provided to illustrate the excellent control performance of the proposed controller in comparison with the existing method.


Lab on a Chip ◽  
2018 ◽  
Vol 18 (14) ◽  
pp. 2099-2110 ◽  
Author(s):  
Yu Gao ◽  
Richard Lakerveld

A novel feedback control method to align colloidal particles reliably via directed self-assembly in a microfluidic device is presented.


Author(s):  
Pradeep Reddy Bonikila ◽  
Ravi Kumar Mandava ◽  
Pandu Ranga Vundavilli

The path tracking phenomenon of a robotic manipulator arm plays an important role, when the manipulators are used in continuous path industrial applications, such as welding, machining and painting etc. Nowadays, robotic manipulators are extensively used in performing the said tasks in industry. Therefore, it is essential for the manipulator end effector to track the path designed to perform the task in an effective way. In this chapter, an attempt is made to develop a feedback control method for a 4-DOF spatial manipulator to track a path with the help of a PID controller. In order to design the said controller, the kinematic and dynamic models of the robotic manipulator are derived. Further, the concept of inverse kinematics has been used to track different paths, namely a straight line and parabolic paths continuously. The effectiveness of the developed algorithm is tested on a four degree of freedom manipulator arm in simulations.


Author(s):  
Robert Wagner ◽  
Kai Dönnebrink ◽  
Felix Reinker ◽  
Karsten Hasselmann ◽  
Jonas Rejek ◽  
...  

A modular low-speed wind tunnel system was designed and developed. Due to the modular concept, the wind tunnel permitted open-jet operation, cascade testing or closed-circuit operation. The closed-circuit wind tunnel had two test sections, and it had a high quality test-section with variable flow angle that is particular valuable for airfoil or blade testing. Physical calibration of the wind tunnel facility validated the design rules and CFD methods used and demonstrated that these techniques can be employed successfully for future wind tunnel designs. A detailed study of the thermal behavior of the closed-circuit wind tunnel was conducted. A feedback control method based on a PI control law was developed and tested for the wind tunnel speed.


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