scholarly journals On the dynamics modeling of free-floating-base articulated mechanisms and applications to humanoid whole-body dynamics and control

2012 ◽  
Author(s):  
Karim Bouyarmane ◽  
Abderrahmane Kheddar
Keyword(s):  
Whole Body ◽  
Dynamics Modeling ◽  
Floating Base ◽  
Body Dynamics ◽  
Dynamics And Control ◽  
Articulated Mechanisms ◽  
And Control

Dynamics and control of a 6-DOF space robot with flexible panels

2016 ◽  
Vol 231 (6) ◽  
pp. 1022-1034 ◽  
Author(s):  
Yu Zhang-Wei ◽  
Liu Xiao-Feng ◽  
Li Hai-Quan ◽  
Cai Guo-Ping
Keyword(s):  
Dynamic Model ◽  
Control Method ◽  
Torque Control ◽  
Space Robot ◽  
Velocity Variation ◽  
Variation Principle ◽  
Dynamics Modeling ◽  
Dynamics And Control ◽  
Flexible Panels ◽  
And Control

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.

scholarly journals Versatile Locomotion Planning and Control for Humanoid Robots

2021 ◽  
Vol 8 ◽  
Author(s):  
Junhyeok Ahn ◽  
Steven Jens Jorgensen ◽  
Seung Hyeon Bang ◽  
Luis Sentis
Keyword(s):  
Trajectory Optimization ◽  
Control Method ◽  
Biped Robot ◽  
Humanoid Robots ◽  
Integer Program ◽  
Whole Body ◽  
Walking Robots ◽  
Planning And Control ◽  
Floating Base ◽  
And Control

We propose a locomotion framework for bipedal robots consisting of a new motion planning method, dubbed trajectory optimization for walking robots plus (TOWR+), and a new whole-body control method, dubbed implicit hierarchical whole-body controller (IHWBC). For versatility, we consider the use of a composite rigid body (CRB) model to optimize the robot’s walking behavior. The proposed CRB model considers the floating base dynamics while accounting for the effects of the heavy distal mass of humanoids using a pre-trained centroidal inertia network. TOWR+ leverages the phase-based parameterization of its precursor, TOWR, and optimizes for base and end-effectors motions, feet contact wrenches, as well as contact timing and locations without the need to solve a complementary problem or integer program. The use of IHWBC enforces unilateral contact constraints (i.e., non-slip and non-penetration constraints) and a task hierarchy through the cost function, relaxing contact constraints and providing an implicit hierarchy between tasks. This controller provides additional flexibility and smooth task and contact transitions as applied to our 10 degree-of-freedom, line-feet biped robot DRACO. In addition, we introduce a new open-source and light-weight software architecture, dubbed planning and control (PnC), that implements and combines TOWR+ and IHWBC. PnC provides modularity, versatility, and scalability so that the provided modules can be interchanged with other motion planners and whole-body controllers and tested in an end-to-end manner. In the experimental section, we first analyze the performance of TOWR+ using various bipeds. We then demonstrate balancing behaviors on the DRACO hardware using the proposed IHWBC method. Finally, we integrate TOWR+ and IHWBC and demonstrate step-and-stop behaviors on the DRACO hardware.

scholarly journals Multi-Body Dynamics Modeling and Control for Strapdown Inertially Stabilized Platforms Considering Light Base Support Characteristics

2020 ◽  
Vol 10 (20) ◽  
pp. 7175
Author(s):  
Zhongshi Wang ◽  
Dapeng Tian ◽  
Lei Shi ◽  
Jinghong Liu
Keyword(s):  
Disturbance Compensation ◽  
Dynamics Modeling ◽  
Tracking Accuracy ◽  
Dynamics Model ◽  
Modeling And Control ◽  
Body Dynamics ◽  
Feedforward Controller ◽  
Multi Body ◽  
And Control ◽  
Compound Disturbance

The dynamics model used for inertially or strapdown inertially stabilized platforms is based on the rotor and motor load, and it either does not consider the stator or it implicitly assumes a fixed stator. It has been determined that vibrations occur in the system when a controller is used in strapdown inertially stabilized platforms with a light base support. As the system is also affected by multi-source disturbances, which are the main factors that affect the control accuracy. For the above two problems, this paper originally establishes a multi-body dynamics model including the controller. The composite controller not only suppresses the vibration successfully, but also greatly improves the disturbance compensation and tracking performance of the strapdown inertially stabilized platforms. Specifically, a modified feedback controller is used to suppress the vibrations analyzed according to the dynamics model. The friction feedforward and residual disturbance observer facilitates the design of compound disturbance compensation on the basis of composite hierarchical anti-disturbance control. To emphasize the advantages of strapdown inertially stabilized platforms, the feedforward controller employs feedforward angular velocity and acceleration. The results of the numerical analysis and experiments indicate that vibrations are successfully suppressed and tracking accuracy and disturbance isolation ability are improved.

Robust push recovery by whole-body dynamics control with extremal accelerations

Robotica ◽  
2013 ◽  
Vol 32 (3) ◽  
pp. 467-476 ◽  
Author(s):  
Xuechao Chen ◽  
Qiang Huang ◽  
Zhangguo Yu ◽  
Yuepin Lu
Keyword(s):  
Whole Body ◽  
Vector Method ◽  
Inverted Pendulum Model ◽  
Push Recovery ◽  
Floating Base ◽  
Pendulum Model ◽  
Body Dynamics ◽  
Robustness Criterion ◽  
External Forces ◽  
Recovery Methods

SUMMARYThis paper presents a whole-body dynamics controller for robust push recovery on a force-controlled bipedal robot. Featherstone's spatial vector method is used to deduce dynamics formulas. We reveal a relationship between the accelerations of the floating base and the desired external forces needed for those accelerations. Introducing constraints on the desired external forces causes corresponding constraints on the accelerations. Quadratic programming is applied to find the extremal accelerations, which recover the robot from pushes as best as possible. A robustness criterion is proposed based on the linear inverted pendulum model to evaluate the performance of push recovery methods quantitatively. We evaluate four typical push recovery methods and the results show that our method is more robust than these. The effectiveness of the proposed method is demonstrated by push recovery in simulations.

scholarly journals Optimizing Electric Adjustment Mechanism Using the Combination of Multi-body Dynamics and Control

2019 ◽  
Vol 35 ◽  
pp. 1363-1369
Author(s):  
Yu Congyang ◽  
Zhu Dequan ◽  
Wang Chaoxian ◽  
Zhu Lin ◽  
Chu Tingting ◽  
...  
Keyword(s):  
Adjustment Mechanism ◽  
Body Dynamics ◽  
Dynamics And Control ◽  
Multi Body ◽  
And Control

PROJECT ON ELECTRONIC STEERING SYSYTEM

2018 ◽  
Vol 4 (5) ◽  
pp. 7
Author(s):  
Shivam Dwivedi ◽  
Prof. Vikas Gupta
Keyword(s):  
Steering System ◽  
Essential Elements ◽  
Variable Pressure ◽  
Passenger Cars ◽  
Control Techniques ◽  
Steering Mechanism ◽  
Dynamics And Control ◽  
Active Research ◽  
Electronic Steering ◽  
And Control

As the four-wheel steering (4WS) system has great potentials, many researchers' attention was attracted to this technique and active research was made. As a result, passenger cars equipped with 4WS systems were put on the market a few years ago. This report tries to identify the essential elements of the 4WS technology in terms of vehicle dynamics and control techniques. Based on the findings of this investigation, the report gives a mechanism of electronically controlling the steering system depending on the variable pressure applied on it. This enhances the controlling and smoothens the operation of steering mechanism.

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