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Acta Mechanica Sinica 2019年第4期35卷 866-878页

作者： Bo Tian Subhrajit Bhattacharya Department of Mechanical Engineering and Mechanics Lehigh University Bethlehem PA 18015 USA

We study the problem of dynamically controlling the shape of a cable that is fixed at one end and attached to an actuated robot at another end. This problem is relevant to unmanned aerial vehicles (UAVs) tethered to a base. While rotorcrafts, such as quadcopters, are agile and versatile in their applications and have been widely used in scientific, industrial and military applications, one of the biggest challenges with such UAVs is their limited battery life that make the flight time for a typical UAVs limited to twenty to thirty minutes for most practical purposes. A solution to this problem lies in the use of cables that tether the UAV to a power outlet for constant power supply. However, the cable needs to be controlled effectively in order to avoid obstacles or other UAVs. In this paper, we develop methods for controlling the shape of a cable using actuation at one end. We propose a discrete model for the spatial cable and derive the equations governing the cable dynamics for both force controlled system and position controlled system. We design a controller to control the shape of the cable to attain the desired shape and perform simulations under different conditions. Finally, we propose a quasi-static model for the spatial cable and discuss the stability of this system and the proposed controller.

关键词： Lagrangian mechanics Discrete model of cable Control of under-actuated systems

Adaptive back-stepping control on container ships for path following

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Journal of Systems Engineering and Electronics 2020年第4期31卷 780-790页

作者： ZHAO Yang DONG Lili Physics and Engineering Department Taylor UniversityUpland IN 46989USA Department of Electrical Engineering and Computer Science Cleveland State UniversityCleveland OH 44115USA

A feedback-dominance based adaptive back-stepping(FDBAB) controller is designed to drive a container ship to follow a predefined path. In reality, current, wave and wind act on the ship and produce unwanted disturbances to the ship control *** FDBAB controller has to compensate for such disturbances and steer the ship to track the predefined(or desired) path. The difference between the actual and the desired path along which the ship is to sail is defined as the tracking error. The FDBAB controller is built on the tracking error model which is developed based on Serret-Frenet frame transformation(SFFT). In additional to being affected by external disturbances, the ship has more outputs than inputs(under-actuated), and is inherently *** back-stepping controller in FDBAB is used to compensate the nonlinearity. The adaptive algorithms in FDBAB is employed to approximate disturbances. Lyapunov's direct method is used to prove the stability of the control system. The FDBAB controlled system is implemented in Matlab/Simulink. The simulation results verify the effectiveness of the controller in terms of successful path tracking and disturbance rejection.

关键词： under-actuated nonlinear environmental disturbance path following Serret-Frenet frame transformation(SFFT) ship steering

Periodic Motion Planning and Control for Double Rotary Pendulum via Virtual Holonomic Constraints

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IEEE/CAA Journal of Automatica Sinica 2019年第1期6卷 291-298页

作者： Zeguo Wang Leonid B.Freidovich Honghua Zhang Beijing Institute of Control Engineering IEEE the Robotics and Control Laboratory (www.control.tfe.umu.se) Department of Applied Physics and ElectronicsUmea University

Periodic motion planning for an under-actuated system is rather difficult due to differential dynamic constraints imposed by passive dynamics, and it becomes more difficult for a system with higher underactuation degree, that is with a higher difference between the number of degrees of freedom and the number of independent control inputs. However, from another point of view, these constraints also mean some relation between state variables and could be used in the motion *** consider a double rotary pendulum, which has an underactuation degree 2. A novel periodic motion planning is presented based on an optimization search. A necessary condition for existence of the whole periodic trajectory is given because of the higher underactuation degree of the system. Moreover this condition is given to make virtual holonomic constraint(VHC) based control design feasible. Therefore, an initial guess for the optimization of planning a feasible periodic motion is based on this necessary condition. Then, VHCs are used for the system transformation and transverse linearization is used to design a static state feedback controller with periodic matrix function gain. The controller gain is found through another optimization procedure. The effectiveness of initial guess and performance of the closed-loop system are illustrated through numerical simulations.

关键词： Double rotary pendulum periodic motion planning under-actuated mechanical systems virtual holonomic constraint (VHC)

Control of a Two-wheeled Machine with Two-directions Handling Mechanism Using PID and PD-FLC Algorithms

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International Journal of Automation and computing 2019年第4期16卷 511-533页

作者： Khaled M. Goher Sulaiman O. Fadlallah School of Engineering University of Lincoln Lincoln LN6 7TS UK Mechanical Engineering Department Auckland University of Technology Auckland 1142 New Zealand

This paper presents a novel five degrees of freedom (DOF) two-wheeled robotic machine (TWRM) that delivers solutions for both industrial and service robotic applications by enlarging the vehicle′s workspace and increasing its flexibility. Designing a two-wheeled robot with five degrees of freedom creates a high challenge for the control, therefore the modelling and design of such robot should be precise with a uniform distribution of mass over the robot and the actuators. By employing the Lagrangian modelling approach, the TWRM′s mathematical model is derived and simulated in Matlab/Simulink?. For stabilizing the system′s highly nonlinear model, two control approaches were developed and implemented: proportional-integral-derivative (PID) and fuzzy logic control (FLC) strategies. Considering multiple scenarios with different initial conditions, the proposed control strategies′ performance has been assessed.

关键词： Two-wheeled inverted pendulum (IP) with two direction handling Lagrangian formulation proportional-integral-derivative (PID) fuzzy logic control (FLC) under-actuated systems

HIT anthropomorphic robotic hand and finger motion control

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Journal of Harbin Institute of Technology(New Series) 2006年第1期13卷 48-53页

作者：高晓辉史士才赵大威姜力王智洋蔡鹤皋刘宏 Robot Research Institute Harbin Institute of Technology Harbin 150001 China Institute of Robotics and Mechatronics German Aerospace Center DLR 82230 Wessling Germany

Nowadays many anthropomorphic robotic hands have been put forward. These hands emphasize different aspects according to their applications. HIT Anthropomorphic Robotic Hand (ARhand) is a simple, lightweight and dexterous design per the requirements of anthropomorphic robots. underactuated self-adaptive theory is adopted to decrease the number of motors and weight. The fingers of HIT ARhand with multi phalanges have the same size as those of an adult hand. Force control is realized with the position sensor, joint torque sensor and fingertip torque sensor. From the 3D model, the whole hand, with the low power consumption DSP control board integrated in it, will weigh only 500 g. It will be assembled on a BIT-Anthropomorphic Robot.

关键词： anthropomorphic robotic hand under-actuated force sensor

A Back-stepping Control Strategy for the Tri-rotor UAV

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A Back-stepping Control Strategy for the Tri-rotor UAV