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Dynamic models that consider multiple nonlinear factors including the two-dimensional deformation and higher-order modes are too computationally complex to be suitable for real-time control of the rotating Euler-Bernoulli beam. This article proposes a new dynamic modeling method according to the assumed mode method. The new modeling method not only has high modeling accuracy but also has a brief mathematical expression. In addition, based on the new modeling method, a neural network sliding mode control strategy using the saturation function is designed to improve the rotational accuracy of the Euler-Bernoulli beam. In the control law design, the saturation function is proposed instead of the unit step function to reduce the chattering phenomenon. Simulation and control experiments describe that the new dynamic modeling method has higher modeling accuracy than the modeling method based on the one-dimensional deformation; the proposed strategy can effectively decrease the rotation angle tracking error of the rotating Euler-Bernoulli beam and improve the control accuracy. [ABSTRACT FROM AUTHOR]

The raceway damage of the bearing restricts the operation stability of the system. Therefore, in the case of damage, simulating vibration response and predicting the performance of the shaft-cylindrical roller-bearing-pedestal system have high research value. According to the structural characteristics and the force transfer relationship, a dynamic model of the shaft-cylindrical roller-bearing-pedestal system is established in this paper. Then, the vibration response of the system is simulated by Runge–Kutta algorithm and measured by experiment. Finally, the effects of load and speed, damage size, and radial clearance on the dynamic performance are investigated. The simulation and measurement results indicate that the load F and the speed N can promote the enhancement of the vibration acceleration signal. As the damage length continues to increase, the ring in the Poincaré map begins to break, and the system transits from quasi-periodic to chaotic motion. The vibration signal is more affected by the damage size than by the damage location. When the radial clearance increases from 5 × 10−6 m to 15 × 10−6 m, the PTP value increases from 23.83 m·s−2 to 61.36 m·s−2. [ABSTRACT FROM AUTHOR]

Dynamic performance of the power transmission line inspection robots (PTLIRs) is of great importance, which would heavily affect the stability of the robot during obstacle avoidance. In this paper, a detailed dynamic performance analysis method of PTLIR is presented by considering the effect on the mechatronic system caused by obstacle avoidance. First, the dynamic modeling of the robot and control system model of the revolute joint are given based on the mechatronic modeling. Then, dynamic characteristics of mechanical subsystem are analyzed by studying the change of the inertia matrix during obstacle avoidance. Next, to analyze the control subsystem performance, three kinds of pole assignment methods which used to tune the controller parameter are compared. Finally, a series of numerical simulations are performed, which prove the time-varying characteristic of load inertia during obstacle avoidance has a great influence on the dynamic performance of the robot, moreover, the changes of natural angular frequency and damping coefficient parameters could be used to evaluate dynamic performance. The main results of the paper can provide an effective tool to analysis dynamic performance of the PTLIR, which is meaningful to improve inspection stability. [ABSTRACT FROM AUTHOR]

Many factors lead to fluctuations of output speed in the motor side during the movement processes in a flexible manipulator with an axially translating arm. These factors include the time‐varying characteristics of manipulator parameters, external disturbance, and flexibility in the manipulator. The vibration of flexible manipulators is strengthened by fluctuations of output speed, which seriously affects the motion accuracy. Therefore, a variable parameters proportional–integral (PI) control strategy based on disturbance observer is adopted to reduce fluctuations of output speed in a dual flexible servo system. First, the dynamic model of the dual flexible servo system is established by the assumed mode method. Then, the variable parameters PI control strategy is applied to the servo system, and the controller parameters in different conditions are selected by pole placement strategies. Finally, numerical simulations and control experiments of the servo system are carried out. The results show that the control strategy using the variable parameters and disturbance observer could reduce fluctuations of output speed and improve the motion accuracy of flexible manipulators. [ABSTRACT FROM AUTHOR]