scholarly journals Space Detumbling Robot Arm Deployment Path Planning Based on Bi-FMT* Algorithm

Micromachines ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 1231
Author(s):  
Ning Chen ◽  
Yasheng Zhang ◽  
Wenhua Cheng
Keyword(s):  
Path Planning ◽  
Robot Dynamics ◽  
Robot Arm ◽  
End Effector ◽  
Constraint Analysis ◽  
Safety And Reliability ◽  
Problem Description ◽  
Translational Joint ◽  
Algorithm Implementation ◽  
Detailed Derivation

In order to avoid damage to service satellites and targets during space missions and improve safety and reliability, it is necessary to study how to eliminate or reduce the rotation of targets. This paper focused on a space detumbling robot and studied the space detumbling robot dynamics and robot arm deployment path planning. Firstly, a certain space detumbling robot with a ‘platform + manipulator + end effector’ configuration is proposed. By considering the end effector as a translational joint, the entire space detumbling robot is equivalent to a link system containing six rotating joints and three translational joints, and the detailed derivation process of the kinematic and dynamic model is presented. Then, ADAMS and MATLAB were used to simulate the model, and the MATLAB results were compared with the ADAMS results to verify the correctness of the model. After that, the robot arm deployment problem was analyzed in detail from the aspects of problem description, constraint analysis and algorithm implementation. An algorithm of robot arm deployment path planning based on the Bi-FMT* algorithm is proposed, and the effectiveness of the algorithm is verified by simulation.

Motion Analysis of Robot Arm With Movement Restriction

2016 ◽  
Author(s):  
Celeste Colberg Poley ◽  
Balakumar Balachandran
Keyword(s):  
Path Planning ◽  
Degrees Of Freedom ◽  
Robotic Manipulator ◽  
Robot Arm ◽  
Initial State ◽  
Movement Restriction ◽  
End Effector ◽  
Goal State ◽  
Planning Algorithm ◽  
Manipulator Arm

Medical robots are increasingly being used to assist surgeons during procedures requiring precision. As reported in the literature, surgeons have been opting for minimally invasive surgery, as it reduces patient complications, overall patient recovery time, and hospital time for the patient. Robotic manipulators can be used to overcome natural limitations related to vision and human dexterity, and allow surgeons to transcend these limitations without having to sacrifice improvement in patient outcome. A desirable attribute of surgical robots is maneuverability similar to the human arm. The KUKA DLR Lightweight Robot Arm (LWR), with seven degrees of freedom, retains many of these human-like dexterity traits. Due to the KUKA robot arms maneuverability and flexibility, it is well-suited for intricate tasks based upon motion analyses and modeling of the compliance to path trajectory in addition to the overall smoothness of the path. This robot may be further programmed to be effective and precise for surgical applications. In the studies reported here, a unique Rapidly exploring Randomized Tree (RRT) based path-planning algorithm is developed and this algorithm is used to generate path plans between an initial state and a goal state for simulated models of robotic manipulator arms. Along with constraints, the RRT algorithm has been implemented to find paths for the chosen kinematic or dynamic robotic manipulator arm. Similar techniques are to be used to analyze the KUKA LWR IV+ system. Motion analyses have been carried out with consideration of motion trajectories and all possible locations of the end effector with unique constraints applied to the system. In these simulations, the Denavit-Hartenberg parameters were recorded, with special attention to movement restrictions. The results of the RRT paths generation, analysis of the manipulator arm trajectories, and simulations allow one to better determine the location of the end-effector at any given point in time and location. From this foundation, the generation of path-planning restrictions for the KUKA robots path programming is expected to take into account surgically restricted dangerous or undesirable zones. In future work, the trajectories of the KUKA robot and other manipulator arms are to be compared with the data available in the literature. This work holds promising implications for the improved use of such robot systems in surgical applications. For example, precise pre-programmed robotic movements are expected to be particularly helpful for surgeries in tight, anatomically restricted sites, with adjacent delicate tissues. Ultimately, it is expected that this type of novel robotic application will greatly aid surgeons in improving the precision and safety of surgical procedures, by reducing potential complications and minimizing potential nicks and tears, and working towards giving the surgeons the same ease that they have with traditional surgery.

Kinematic path control of robot arms

Robotica ◽  
1986 ◽  
Vol 4 (2) ◽  
pp. 107-116 ◽  
Author(s):  
Evgeny Krustev ◽  
Ljubomir Lilov
Keyword(s):  
Path Planning ◽  
Velocity Profile ◽  
New Method ◽  
Robot Arm ◽  
Optimal Motion ◽  
End Effector ◽  
Path Control ◽  
Time Optimal ◽  
Simulation Results ◽  
Arm Motion

SUMMARYPath planning of the end effector motion is here treated from the viewpoint of the path invariance under the transformations of its parametrical representation. Thus, a new method for path planning of the robot arm motion is being developed. Both the problems of finding the end effector time optimal motion and the end effector motion with a prescribed velocity profile along a preplanned path are being solved by the employment of this method. Simulation results are presented and some aspects of implementation are also discussed.

Three-Degree-of-Freedom Parallel Robot Arm

2006 ◽  
Author(s):  
Martin Hosek ◽  
Michael Valasek ◽  
Jairo Moura
Keyword(s):  
Parallel Robot ◽  
Degree Of Freedom ◽  
Motion Path ◽  
Angular Orientation ◽  
Robot Arm ◽  
Flat Panel Display ◽  
End Effector ◽  
Cluster Tools ◽  
Manufacturing Applications ◽  
Three Degree Of Freedom

This paper presents single- and dual-end-effector configurations of a planar three-degree of freedom parallel robot arm designed for automated pick-place operations in vacuum cluster tools for semiconductor and flat-panel-display manufacturing applications. The basic single end-effector configuration of the arm consists of a pivoting base platform, two elbow platforms and a wrist platform, which are connected through two symmetric pairs of parallelogram mechanisms. The wrist platform carries an end-effector, the position and angular orientation of which can be controlled independently by three motors located at the base of the robot. The joints and links of the mechanism are arranged in a unique geometric configuration which provides a sufficient range of motion for typical vacuum cluster tools. The geometric properties of the mechanism are further optimized for a given motion path of the robot. In addition to the basic symmetric single end-effector configuration, an asymmetric costeffective version of the mechanism is derived, and two dual-end-effector alternatives for improved throughput performance are described. In contrast to prior attempts to control angular orientation of the end-effector(s) of the conventional arms employed currently in vacuum cluster tools, all of the motors that drive the arm can be located at the stationary base of the robot with no need for joint actuators carried by the arm or complicated belt arrangements running through the arm. As a result, the motors do not contribute to the mass and inertia properties of the moving parts of the arm, no power and signal wires through the arm are necessary, the reliability and maintenance aspects of operation are improved, and the level of undesirable particle generation is reduced. This is particularly beneficial for high-throughput applications in vacuum and particlesensitive environments.

Robot Path Planning and Obstacle Avoidance: A Design Optimization Approach

1989 ◽  
Author(s):  
E. Sandgren ◽  
S. Venkataraman
Keyword(s):  
Path Planning ◽  
Design Optimization ◽  
Dynamic Programming Algorithm ◽  
Three Dimensional ◽  
Programming Algorithm ◽  
Optimization Approach ◽  
Robot Arm ◽  
Robot Path Planning ◽  
Real Time Control ◽  
Robot Path

Abstract A design optimization approach to robot path planning in a two dimensional workplace is presented. Obstacles are represented as a series of rectangular regions and collision detection is performed by an operation similar to clipping in computer graphics. The feasible design space is approximated by a discrete set of robot arm and gripper positions. Control is applied directly through the angular motion of each link. Feasible positions which are located between the initial and final robot link positions are grouped into stages. A dynamic programming algorithm is applied to locate the best state within each stage which minimizes the overall path length. An example is presented involving a three link planar manipulator. Extensions to three dimensional robot path planning and real time control in a dynamically changing workplace are discussed.

Cooperation and Null-Space Control of Networked Omni-Directional Mobile Manipulators

2020 ◽  
Author(s):  
Michael John Chua ◽  
Yen-Chen Liu
Keyword(s):  
Degrees Of Freedom ◽  
Null Space ◽  
Kinematic Model ◽  
Mobile Manipulator ◽  
Main Task ◽  
Mobile Manipulators ◽  
Robot Arm ◽  
Task Space ◽  
End Effector ◽  
Mobile Base

Abstract This paper presents cooperation and null-space control for networked mobile manipulators with high degrees of freedom (DOFs). First, kinematic model and Euler-Lagrange dynamic model of the mobile manipulator, which has an articulated robot arm mounted on a mobile base with omni-directional wheels, have been presented. Then, the dynamic decoupling has been considered so that the task-space and the null-space can be controlled separately to accomplish different missions. The motion of the end-effector is controlled in the task-space, and the force control is implemented to make sure the cooperation of the mobile manipulators, as well as the transportation tasks. Also, the null-space control for the manipulator has been combined into the decoupling control. For the mobile base, it is controlled in the null-space to track the velocity of the end-effector, avoid other agents, avoid the obstacles, and move in a defined range based on the length of the manipulator without affecting the main task. Numerical simulations have been addressed to demonstrate the proposed methods.

scholarly journals Detachable Robotic Grippers for Human-Robot Collaboration

2021 ◽  
Vol 8 ◽  
Author(s):  
Zubair Iqbal ◽  
Maria Pozzi ◽  
Domenico Prattichizzo ◽  
Gionata Salvietti
Keyword(s):  
Degrees Of Freedom ◽  
Tactile Feedback ◽  
Industrial Robots ◽  
Physical Interaction ◽  
Robot Arm ◽  
Robotic Hands ◽  
End Effector ◽  
External Power ◽  
Self Powered ◽  
Automatic Tool

Collaborative robots promise to add flexibility to production cells thanks to the fact that they can work not only close to humans but also with humans. The possibility of a direct physical interaction between humans and robots allows to perform operations that were inconceivable with industrial robots. Collaborative soft grippers have been recently introduced to extend this possibility beyond the robot end-effector, making humans able to directly act on robotic hands. In this work, we propose to exploit collaborative grippers in a novel paradigm in which these devices can be easily attached and detached from the robot arm and used also independently from it. This is possible only with self-powered hands, that are still quite uncommon in the market. In the presented paradigm not only hands can be attached/detached to/from the robot end-effector as if they were simple tools, but they can also remain active and fully functional after detachment. This ensures all the advantages brought in by tool changers, that allow for quick and possibly automatic tool exchange at the robot end-effector, but also gives the possibility of using the hand capabilities and degrees of freedom without the need of an arm or of external power supplies. In this paper, the concept of detachable robotic grippers is introduced and demonstrated through two illustrative tasks conducted with a new tool changer designed for collaborative grippers. The novel tool changer embeds electromagnets that are used to add safety during attach/detach operations. The activation of the electromagnets is controlled through a wearable interface capable of providing tactile feedback. The usability of the system is confirmed by the evaluations of 12 users.

Stable and Unstable Quasiperiodic Oscillations in Robot Dynamics

1993 ◽  
Author(s):  
G. Stépán ◽  
G. Haller
Keyword(s):  
Nonlinear Dynamical Systems ◽  
Dynamical Behavior ◽  
Time Lag ◽  
Nonlinear Behavior ◽  
Degree Of Freedom ◽  
Robot Dynamics ◽  
Robot Arm ◽  
Delayed Systems ◽  
Nonlinear Dynamical ◽  
Quasiperiodic Oscillations

Abstract Delays in robot control may result in unexpectedly sophisticated nonlinear dynamical behavior. Experiments on force controlled robots frequently show periodic and quasiperiodic oscillations which cannot be explained without including the time lag and/or the sampling time of the system in our models. Delayed systems, even of low degree of freedom, can produce phenomena which are already well understood in the theory of nonlinear dynamical systems but hardly ever occur in simple mechanical models. To illustrate this, we analyze the delayed positioning of a single degree of freedom robot arm. The analytical results show typical nonlinear behavior in the system which may go through a codimension two Hopf bifurcation for an infinite set of parameter values, leading to the creation of two-tori in the phase space. These results give a qualitative explanation for the existence of self-excited quasiperiodic oscillations in the dynamics of force controlled robots.

Space Robot Arm Deployment Path Planning Based on FMT*Algorithm

2021 ◽  
Author(s):  
Ning Chen ◽  
Yasheng Zhang ◽  
Wenhua Cheng
Keyword(s):  
Path Planning ◽  
Space Robot ◽  
Robot Arm
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