Optimal Trajectory Tracking Control With a 5R Parallel Robot

Author(s):  
Gianmarc Coppola ◽  
Dan Zhang

This work examines the control characteristics of a 5R parallel robotic manipulator subjected to two control studies. Firstly, fundamental aspects of dynamics are presented. Then a brief review of Particle Swarm Optimization (PSO) and feedforward Neural Networks (NN) is undertaken. Subsequently, to tackle the challenging problem of controller parameter tuning for parallel robots in trajectory tracking scenarios, a multi objective optimization problem is formulated for automatic tuning using PSO. This offline method is comparatively evaluated to the Nelder-Mead (NM) sequential simplex optimization scheme. Several results are attained illustrating the strengths and weaknesses of this method for parallel robot control. Then, an adaptive NN model reference control scheme using PSO is proposed. This scheme is proposed as one possible way to take advantage of the strong properties of the PSO online. The scheme is tested and several observations are outlined.

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Cheng Liu ◽  
Yanming Cheng ◽  
Dejun Liu ◽  
Guohua Cao ◽  
Ilkyoo Lee

In order to better track the planned trajectory of Delta high-speed parallel robot, this paper proposes a dynamics control strategy for Delta high-speed parallel robots based on the linear active disturbance rejection control (LADRC) strategy which realizes decoupling control through observing and compensating the coupling and internal and external disturbances between the three joints. Firstly, the structure and dynamics model of the Delta high-speed parallel robot are analyzed, respectively. Secondly, the control scheme of the Delta high-speed parallel robot dynamic LADRC strategy is constructed, and then, the system stability is analyzed. Taking a representative 8-shaped space helical variance trajectory as a given input of the system and a triangular wave as an external disturbance as given disturbance input of the system, simulations are carried out to demonstrate the effectiveness of the proposed LADRC strategy; results indicate that the system with the LADRC strategy has a good quick and precise real-time trajectory tracking and strong robustness.


2011 ◽  
Vol 328-330 ◽  
pp. 2108-2112
Author(s):  
Jing Shuang Lu ◽  
Chun Mei Du ◽  
Rui Zhou ◽  
Na Li

A simple dynamics model is established based on the two-link flexible manipulator moving within the vertical plane, and a robust simple control scheme is put forward. The advantages of this scheme are simple and good robustness. Only the error signal is needed when designing the control scheme and the acquirement of control signal does not depend on the system model. The simulation results show that this method has a good robustness and stability.


Author(s):  
Yuanhui Wang ◽  
Haibin Wang ◽  
Mingyu Fu

This paper investigates concentrates on the trajectory tracking control problem of dynamic positioning (DP) ship, in the presence of the time-varying disturbance and input saturation. Firstly, a simplified mathematical model of three degrees of freedom is established. According to the characteristics of the DP ship, an adaptive backstepping controller which combine the prescribed performance function with disturbance observer is proposed. The control scheme can guarantee the transient and steady state performance of the trajectory tracking and meet the prescribed performance criteria. In addition, an auxiliary dynamic system is introduced into the controller to deal with the input saturation problem of the actuator, so that the DP ship can accomplish the task of trajectory tracking under the condition of actuator constraint. Subsequently, in combination of barrier Lyapunov function (BLF), it is proved that the DP system can stabilize and converge rapidly to the small neighborhood of the equilibrium point, which can achieve the prescribed performance. Finally, the effectiveness of the DP control law is demonstrated by a series of simulation experiments.


1995 ◽  
Vol 7 (4) ◽  
pp. 344-352 ◽  
Author(s):  
Karol Miller ◽  
◽  
Boris S. Stevens ◽  
◽  

The term ""Extended Space"" used in this article is hereby defined as a union of the operational and articulation spaces of a manipulator. The advantages in the use of such coordinates (extended space) in the description of DELTA robot is presented here and discussed in some detail. The emerging importance of parallel robots has necessitated an increased sophistication to achieve improved control. A method based on the direct application of the Hamilton's Principle in extended space, has been applied efficiently to solving the inverse problem of dynamics and implemented for real time application in the control law of the direct-drive version of DELTA parallel robot.1-3) The full dynamic model of this robot has been developed herein. The numerical efficiency and other benefits of this approach over the more classical Lagrange and Newton-Euler methods for the inverse dynamics problem solving are also briefly discussed. For similar models, the version obtained by the direct application of Hamilton's principle is found to possess 23% less mathematical operations than for the Lagrangebased model. Frictional effects. being very small in the direct-drive manipulator, are not included in the present Hamilton development but can be handled with a slight modification. Furthermore the acceleration information of the robot are not required as input states to the Hamilton model. The measurement of trajectory tracking performances for different controllers is conducted. The repeatability of the robot trajectory tracking is determined. The improvement obtained in the control algorithm's performance after the Hamilton implementation is proven to be conclusive.


2015 ◽  
Vol 799-800 ◽  
pp. 1069-1073
Author(s):  
Hao Tian ◽  
Yue Qing Yu

Trajectory tracking control of compliant parallel robot is presented. According to the characteristics of compliant joint, the system model is derived and the dynamic equation is obtained based on the Lagrange method. Radial Basis Function (RBF) neural network control is designed to globally approximate the model uncertainties. Further, an itemized approximate RBF control method is proposed for higher identify precision. The trajectory tracking abilities of two control strategies are compared through simulation.


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