Electromechanical Coupling Characteristics Analysis and Research of Rotation-Parallel Flexible Robot Manipulator

RP(Rotation-Parallel) flexible robot as a typical electromechanical system. The complex electromechanical coupling effect in the system has a significant impact on the dynamic characteristics and stability of the flexible manipulator. This article investigates the electromechanical coupling dynamics and vibration response characteristics of flexible robot manipulator driven by AC(Alternating Current) servo motor with considering the start-up dynamic characteristics of the motor. Firstly, the physical model including the coupling of electromagnetic and mechanical system is established, and the dynamic model of the whole system is derived based on the global electromechanical coupling effect and Lagrange-Maxwell equations. Secondly, the virtual simulation platform is constructed with the help of MATLAB/Simulink, and the output speed characteristics of the motor drive end and the motion of the moving base are analyzed. Finally, through the joint simulation of MATLAB/Simulink dynamic simulation model and ADAMS/Controls virtual prototype model, the vibration characteristics of flexible manipulator under electromechanical coupling are obtained. The result demonstrates that the electromechanical coupling effect at the motor driving end has an obvious influence on the dynamic characteristics of the flexible manipulator, which is manifested in the increase of the vibration displacement amplitude of the flexible manipulator. With the increase of motor speed, the change of elastic vibration of flexible manipulator becomes larger, which shows that the electromechanical coupling effect of motor driving end has a greater impact on the dynamic characteristics of flexible manipulator at high speed. The analysis results are of great significance to improve the dynamic performance of motor-driven flexible robot manipulator.

Optimum control of a flexible single link manipulator with Artificial Bee Colony Algorithm

This paper presents a stable control for a single link flexible manipulator. The flexible manipulator is considered as Euler–Bernoulli beam, and its dynamic model is developed based on assumed mode method. Position and vibration control are realised with a single controller as motor torque. The controller has three parameters that must be selected. In this paper, the main motivation is to find the suitable parameter values to generate optimum torque values in every sampling time. In order to achieve this goal, Artificial Bee Colony Algorithm is performed, and the controller parameters are optimised simultaneously in every sampling period. Simulations verify that the manipulator achieves the position control objective, and the vibration is suppressed simultaneously even with different payloads with the proposed optimisation method.

Measurement and modeling of a flexible manipulator for vibration control using five-segment S-curve motion

User designed manipulators are widely used in industry as a part of automation. The design of lighter robotic arms is required for less energy consumption. Joints, structural features, and payload affect the dynamic behavior of manipulators. Even if the arms have sufficient structural rigidity, joints, or payloads further increase their flexibility. These factors should be considered at the design stage. Flexibility causes vibrations, and these vibrations negatively affect robot repeatability and processing speed. Reducing the vibration levels of flexible manipulators is an attractive issue for engineers and researchers. Accurate estimation of the mathematical model of flexible manipulators increases the success of vibration control. In this paper, the modeling and experiments for vibration control of a single-axis flexible curved manipulator with payload are considered. The experimental system is introduced to collect vibration responses synchronously at the tip of the curved manipulator for angular velocity input. The mathematical model of the manipulator is estimated using the continuous-time system identification (CTSI) method with a black-box model based on the experimental input/output (I/O) signals. A five-segment S-curve motion input based on the modal parameters is designed to suppress residual vibrations. Vibration control is successfully performed for different deceleration times of the designed S-curve motion input. The results showed that the residual vibrations from experiments and predicted models matched well for different cases depending on payload, angular position, and motion time.

Modelling of Flexible Manipulator System via Ant Colony Optimization for Endpoint Acceleration

The application of flexible manipulators has increased in recent years especially in the fourth industrial revolution. It plays a significant role in a diverse range of fields, such as construction automation, environmental applications, space engineering and many more. Due to the lightweight, lower inertia and high flexibility of flexible manipulators, undesired vibration may occur and affect the precision of operation. Therefore, development of an accurate model of the flexible manipulator was presented prior to establishing active vibration control to suppress the vibration and increase efficiency of the system. In this study, flexible manipulator system was modelled using the input and output experimental data of the endpoint acceleration. The model was developed by utilizing intelligence algorithm via ant colony optimization (ACO), commonly known as a population-based trail-following behaviour of real ants based on autoregressive with exogenous (ARX) model structure. The performance of the algorithm was validated based on three robustness methods known as lowest mean square error (MSE), correlation test within 95% confidence level and pole zero stability. The simulation results indicated that ACO accomplished superior performance by achieving lowest MSE of 2.5171×10−7 for endpoint acceleration. In addition, ACO portrayed correlation tests within 95% confidence level and great pole-zero stability.

Research on Active Control of Rotating Motion and Vibration of Flexible Manipulator

In this study, PZT (piezoelectric) actuators and PD control (PDs’ command line tool) method is selected to control the vibration of the flexible manipulator. The dynamic equations of the flexible manipulator system are established based on Lagrange principle. The control strategy of PZT actuators and joint control torque are designed. It is investigated by a Lyapunov approach that a combined scheme of PD feedback and command voltages applies to segmented PZT actuators. By comparison, only PD feedback control is also considered to control the flexible manipulator. The numerical simulations prove that the method of the designed PZT actuators’ control strategy and PD control is effective to compress the vibration of the flexible manipulator.