Dynamics modeling and control of a 6-DOF space robot with flexible panels for capturing a free floating target

2016 ◽  
Vol 128 ◽  
pp. 560-572 ◽  
Author(s):  
Zhang-wei Yu ◽  
Xiao-feng Liu ◽  
Guo-ping Cai
Author(s):  
Yu Zhang-Wei ◽  
Liu Xiao-Feng ◽  
Li Hai-Quan ◽  
Cai Guo-Ping

With the development of space exploration, researches on space robot will cause more attentions. However, most existing researches about dynamics and control of space robot concern planar problem, and the effect of flexible panel on dynamics of the system is not considered. In this article, dynamics modeling and active control of a 6-DOF space robot with flexible panels are investigated. Dynamic model of the system is established based on the Jourdain's velocity variation principle and the single direction recursive construction method. The computed torque control method is used to design point-to-point active controller of the space robot. The validity of the dynamic model is verified through the comparison with ADAMS software; the effects of panel flexibility on the system performance and the active controller design are studied in detail. Simulation results indicate that the proposed model is effective to describe the dynamics of space robot; panel flexibility has large influence on the dynamic behavior of space robot; the designed controller can effectively make the robot reach a specified position and the elastic vibration of the panels may be suppressed simultaneously.


2019 ◽  
Vol 26 (11-12) ◽  
pp. 989-1000
Author(s):  
Pingxin Wang ◽  
Xiaoting Rui ◽  
Hailong Yu ◽  
Bo Li

Track assemblies are widely used to reduce vehicles’ ground pressure and improve their off-road performance. During off-road, the track tension has a significant effect on the performance of the crawler driving system. Previous control strategies only make use of the motions of partial road wheels. This paper develops a logical improvement to govern the motion of the track tensioner by using all road wheels. First, a dynamic model of the hydraulic-mechanism coupling system is established using the transfer matrix method for multibody systems and pressure-flow equations. Then, in order to get the angle of the idler arm, a modeling method of wheel envelope perimeter is developed, which is based on the locations of all wheels. Simulation results indicate that the control system maintains the wheel envelope perimeter almost constant while road wheels swing and decrease the possibility of peel-off and breakage of the track. It alleviates the track repeated stretch and keeps the tension in a stable range to reduce the fatigue damage. The control strategy can effectively reduce the peak value of the upper track tension during a vehicle passing through obstacles. This study suggests that the active track tensioning system can be implemented to improve the driving properties of tracked vehicles.


2016 ◽  
Vol 2016 ◽  
pp. 1-13 ◽  
Author(s):  
Yanhua Han

Dynamics modeling and control problem of a two-link manipulator mounted on a spacecraft (so-called carrier) freely flying around a space target on earth’s circular orbit is studied in the paper. The influence of the carrier’s relative movement on its manipulator is considered in dynamics modeling; nevertheless, that of the manipulator on its carrier is neglected with the assumption that the mass and inertia moment of the manipulator is far less than that of the carrier. Meanwhile, we suppose that the attitude control system of the carrier guarantees its side on which the manipulator is mounted points accurately always the space target during approaching operation. The ideal constraint forces can be out of consideration in dynamics modeling as Kane method is used. The path functions of the manipulator’s end-effector approaching the space target as well as the manipulator’s joints control torque functions are programmed to meet the soft touch requirement that the end-effector’s relative velocity to the space target is zero at touch moment. Numerical simulation validation is conducted finally.


2014 ◽  
Vol 875-877 ◽  
pp. 1961-1966
Author(s):  
Hui Jin Mu

In recent years, modeling and control of flexible space robots are extensively researched. Compared with traditional rigid robots, flexible robots have low energy consumption, wide operating space, high carrying capacity and other characteristics. However, due to its special structure, the robot arm will get deformation and vibration in motion, which brings a lot of problems to the positioning and tracking control of flexible space robots. Therefore, directing at the dynamics modeling and control issues of the free-floating flexible dual-arm space robots, this article carries out in-depth study. This paper first studies the elastic deformation and vibration of the flexible space manipulator and the robust control problem of the system trajectory tracking for free-floating flexible dual-arm space robots.


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