scholarly journals Feed-forward control of elastic-joint industrial robot based on hybrid inverse dynamic model

2021 ◽  
Vol 13 (9) ◽  
pp. 168781402110381
Author(s):  
Mei Zaiwu ◽  
Chen Liping ◽  
Ding Jianwan

A novel feedforward control method of elastic-joint robot based on hybrid inverse dynamic model is proposed in this paper. The hybrid inverse dynamic model consists of analytical model and data-driven model. Firstly, the inverse dynamic analytical model of elastic-joint robot is established based on Lie group and Lie algebra, which improves the efficiency of modeling and calculation. Then, by coupling the data-driven model with the analytical model, a feed-forward control method based on hybrid inverse dynamics model is proposed. This method can overcome the influence of the inaccuracy of the analytical inverse dynamic model on the control performance, and effectively improve the control accuracy of the robot. The data-driven model is used to compensate for the parameter uncertainties and non-parameter uncertainties of the analytical dynamic model. Finally, the proposed control method is proved to be stable and the multi-domain integrated system model of industrial robot is developed to verify the performance of the control scheme by simulation. The simulation results show that the proposed control method has higher control accuracy than the traditional torque feed-forward control method.

Author(s):  
Hyun-Sik Kim ◽  
Ha-Yong Kim ◽  
Chong-Won Lee ◽  
Tae-Ha Kang

The active magnetic bearing (AMB) systems mounted in moving vehicles are exposed to the disturbances due to the base motion, often leading to malfunction or damage as well as inaccurate positioning of the systems. Thus, in the controller design of such AMB systems, robustness to base disturbances becomes an essential requirement. In this study, effective control schemes are proposed for the homo-polar AMB system, which uses permanent magnets for generation of bias magnetic flux, when it is subject to base motion, and its control performance is experimentally evaluated. The base motion of AMB system is modeled as the dynamic disturbances in the gravity and base excitation forces. To effectively compensate for the disturbances, the angle feed-forward controller based on the inverse dynamic model and the acceleration feed-forward controller based on the normalized filtered-X LMS algorithm and the inverse dynamic model are proposed. The performance test of the prototype AMB system is carried out, when the system is mounted on a six degrees-of-freedom motion platform. The experimental results show that the performance of the proposed controllers for the AMB system is satisfactory in compensating for the disturbances due to the base motion.


2010 ◽  
Vol 63 (1) ◽  
pp. 3-23 ◽  
Author(s):  
Peter Paul Pott ◽  
Achim Wagner ◽  
Essameddin Badreddin ◽  
Hans-Peter Weiser ◽  
Markus L. R. Schwarz

Symmetry ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 1849
Author(s):  
Jianbo Liu ◽  
Rongqiang Guan ◽  
Yongming Yao ◽  
Hui Wang ◽  
Linqiang Hu

In this paper, we propose a novel kinematic and inverse dynamic model for the flybar-less (FBL) swashplate mechanism of a small-scale unmanned helicopter. The swashplate mechanism is an essential configuration of helicopter flight control systems. It is a complex, multi-loop chain mechanism that controls the main rotor. In recent years, the demand for compact swashplate designs has increased owing to the development of small-scale helicopters. The swashplate mechanism proposed in this paper is the latest architectures used for hingeless rotors without a Bell-Hiller mixer. Firstly, the kinematic analysis is derived from the parallel manipulators concepts. Then, based on the principle of virtual work, a methodology for deriving a closed-form dynamic equation of the FBL swashplate mechanism is developed. Finally, the correctness and efficiency of the presented analytical model are demonstrated by numerical examples and the influence factors of the loads acted on actuators are discussed.


Author(s):  
Ming Li ◽  
Huapeng Wu ◽  
Heikki Handroos ◽  
Marco Ceccarelli ◽  
Giuseppe Carbone

Due to the high stiffness, high dynamic performance, the parallel manipulator presents great advantages in the industrial manufacture. However in the machining process, the external low frequency disturbance, e.g. the varying cutting force, has a significant effect on the control system of parallel manipulator, which presents a chatter phenomenon on the end-effector of manipulator. In this paper, a feed forward control strategy is proposed to eliminate the effect of the random external disturbance on the control system of parallel manipulator. By applying the external disturbance force on the inverse dynamic model, the compensation torque is calculated and fed forward into the manipulator driving joints to cancel out the effect of the disturbance acting on the manipulator end-effector. The key issue herein is to be able to establish the accurate dynamic model for the parallel manipulator. Furthermore, in order to guarantee the position precision of the manipulator, a feed forward model-based control strategy combined with the feedback loop PV (position and velocity) control has been developed based on the reference trajectory, which could relatively simplify the highly nonlinear control system of the parallel manipulator and obtain a stable tracking error model. The whole research has been carried out on a parallel manipulator named CaPaMan which has been built in the laboratory of robotics and mechatronics in university of Cassino and South Latium. The results show that the chatter phenomenon could be utterly depressed by the force compensation from the feed forward path of the external disturbance; meanwhile the model-based controller can guarantee the trajectory tracking accuracy within a stable error by choosing the suitable PV gains.


2007 ◽  
Vol 27 (6) ◽  
pp. 1346-1355 ◽  
Author(s):  
A. M. Green ◽  
H. Meng ◽  
D. E. Angelaki

Author(s):  
Dalei Pan ◽  
Feng Gao ◽  
Yunjie Miao

This article proposes a novel type of series-parallel lower extremity exoskeleton driven by hydraulic actuators. Each leg of the exoskeleton has six DOFs, which can walk like human and carry heavy loads. A mapping from the positions of human lower extremity joints to the exoskeleton joints was established. Based on Kane's method, the inverse dynamic model of the exoskeleton was conducted. Finally, the exoskeleton humanoid gaits of level walking, ascent, descent, level walking with different loads and speed were simulated, and the required driving torques and power were obtained. These performance analyses provide a basis to the design of the control law and the estimation of the hydraulic actuator parameters for the exoskeleton.


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