scholarly journals Relative Motion Dynamics Modeling and Control of DFP Vibration Isolation Spacecraft

Author(s):  
Yongxing Tang ◽  
Zhanxia Zhu

In order to better meet the future high precision task requirements, the DFP(Disturbance-Free Payload) spacecraft composed of non-contact PM(Payload Module)and SM(Support Module)is taken as the object to study the relative motion dynamics modeling and control between the two modules and verify the system vibration isolation performance. Firstly, the force and torque expressions of the two modules are derived by simplifying the configuration and analyzing the stress. In view of that couple effect, the relative motion dynamics equations between two modules of DFP spacecraft with high model accuracy, and simple and uniform format are established with the dual quaternions. Based on this, the PD control law is designed, and the relative motion of PM and SM could meet DFP spacecraft working requirements when the measurability of control quantity and the measurement error of sensors were taken into account. Simulation results verify the advantage of vibration isolation and attitude maneuverability of DFP spacecraft.

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.


Author(s):  
A. Narimani ◽  
M. F. Golnaraghi

Semi-active isolators offer significant improvement in performance over passive isolators. These systems benefit from the advantages of active systems with the reliability of the passive systems. In this work we study a vibration isolation system with a magnetorheological (MR) damper. The experimental investigation of the mechanical properties of a commercially available linear MR damper (RD-1005-3) was conducted next. The mathematical Bouc-Wen model was adopted to predict the performance of MR damper. In addition, a modified Bingham model has been developed to characterize the damper behavior more accurately and efficiently. The measured hysteresis characteristics of field-dependent damping forces are compared with the simulation results from the described mathematical models. The accuracy of a damping-force controller using the proposed method is also demonstrated experimentally. Finally, a scaled quarter car model is set up to study the performance of the control strategy. The experimental results show that with the semi-active control the vibration of the quarter car model is well controlled.


2017 ◽  
Vol 40 (8) ◽  
pp. 1837-1859 ◽  
Author(s):  
Joshua Sullivan ◽  
Sebastian Grimberg ◽  
Simone D’Amico

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.


Sign in / Sign up

Export Citation Format

Share Document