LENGTH-OPTIMIZED SMOOTH OBSTACLE AVOIDANCE FOR ROBOTIC MANIPULATORS

2011 ◽  
Vol 35 (4) ◽  
pp. 505-514 ◽  
Author(s):  
Soheil S. Parsa ◽  
Juan A. Carretero ◽  
Roger Boudreau
Keyword(s):  
Harmonic Function ◽  
Obstacle Avoidance ◽  
Robotic Manipulators ◽  
Joint Space ◽  
Displacement Velocity ◽  
End Effector ◽  
Smooth Path ◽  
Simulation Results

This paper presents a novel optimized smooth obstacle avoidance algorithm for robotic manipulators. First, a 3-4-5 interpolating polynomial is used to plan a smooth trajectory between initial and final positions in the joint space without considering any obstacles. Then, a simple harmonic function, which is smooth and continuous in displacement, velocity and acceleration, is applied to generate a new smooth path avoiding collisions between the robot links and an obstacle. The obstacle avoidance portions on the path are optimized such that the length of the path traversed by the end-effector is minimized. Simulation results for a 6 DOF serial manipulator demonstrate the efficiency of the proposed method.

New repetitive motion planning scheme with cube end-effector planning precision for redundant robotic manipulators

Robotica ◽  
2021 ◽  
pp. 1-22
Author(s):  
Limin Shen ◽  
Yuanmei Wen
Keyword(s):  
Theoretical Analysis ◽  
Motion Planning ◽  
Robotic Manipulators ◽  
Robotic Manipulator ◽  
Repetitive Motion ◽  
End Effector ◽  
Difference Formula ◽  
Planning Scheme ◽  
Simulation Results ◽  
The Difference

Abstract Repetitive motion planning (RMP) is important in operating redundant robotic manipulators. In this paper, a new RMP scheme that is based on the pseudoinverse formulation is proposed for redundant robotic manipulators. Such a scheme is derived from the discretization of an existing RMP scheme by utilizing the difference formula. Then, theoretical analysis and results are presented to show the characteristic of the proposed RMP scheme. That is, this scheme possesses the characteristic of cube pattern in the end-effector planning precision. The proposed RMP scheme is further extended and studied for redundant robotic manipulators under joint constraint. Based on a four-link robotic manipulator, simulation results substantiate the effectiveness and superiority of the proposed RMP scheme and its extended one.

scholarly journals Optimization of Dynamic Task Location within a Manipulator’s Workspace for the Utilization of the Minimum Required Joint Torques

Electronics ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 288
Author(s):  
Adam Wolniakowski ◽  
Charalampos Valsamos ◽  
Kanstantsin Miatliuk ◽  
Vassilis Moulianitis ◽  
Nikos Aspragathos
Keyword(s):  
High Performance ◽  
Human Robot Interaction ◽  
Optimal Position ◽  
End Effector ◽  
Joint Torques ◽  
Dynamic Task ◽  
Arbitrary Position ◽  
Simulation Results ◽  
Set Up ◽  
Task Placement

The determination of the optimal position of a robotic task within a manipulator’s workspace is crucial for the manipulator to achieve high performance regarding selected aspects of its operation. In this paper, a method for determining the optimal task placement for a serial manipulator is presented, so that the required joint torques are minimized. The task considered comprises the exercise of a given force in a given direction along a 3D path followed by the end effector. Given that many such tasks are usually conducted by human workers and as such the utilized trajectories are quite complex to model, a Human Robot Interaction (HRI) approach was chosen to define the task, where the robot is taught the task trajectory by a human operator. Furthermore, the presented method considers the singular free paths of the manipulator’s end-effector motion in the configuration space. Simulation results are utilized to set up a physical execution of the task in the optimal derived position within a UR-3 manipulator’s workspace. For reference the task is also placed at an arbitrary “bad” location in order to validate the simulation results. Experimental results verify that the positioning of the task at the optimal location derived by the presented method allows for the task execution with minimum joint torques as opposed to the arbitrary position.

scholarly journals An Obstacle Avoidance Method for Action Support 7-DOF Manipulators Using Impedance Control

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Masafumi Hamaguchi ◽  
Takao Taniguchi
Keyword(s):  
Angular Velocity ◽  
Obstacle Avoidance ◽  
Impedance Control ◽  
Kinematic Redundancy ◽  
End Effector ◽  
Rate Vector

An obstacle avoidance method of action support 7-DOF manipulators is proposed in this paper. The manipulators are controlled with impedance control to follow user's motions. 7-DOF manipulators are able to avoid obstacles without changing the orbit of the end-effector because they have kinematic redundancy. A joint rate vector is used to change angular velocity of an arbitrary joint with kinematic redundancy. The priority of avoidance is introduced into the proposed method, so that avoidance motions precede follow motions when obstacles are close to the manipulators. The usefulness of the proposed method is demonstrated through obstacle avoidance simulations and experiments.

scholarly journals Stiffness Modeling of Robotic-Manipulators Under Auxiliary Loadings

2012 ◽  
Author(s):  
Alexandr Klimchik ◽  
Anatol Pashkevich ◽  
Stéphane Caro ◽  
Damien Chablat
Keyword(s):  
Robotic Manipulators ◽  
Computationally Efficient ◽  
End Effector ◽  
Efficient Procedure ◽  
Stiffness Modeling ◽  
Cartesian Stiffness Matrix ◽  
Different Types ◽  
Mapping Equation ◽  
Linear Force ◽  
Cartesian Stiffness

The paper focuses on the extension of the virtual-joint-based stiffness modeling technique for the case of different types of loadings applied both to the robot end-effector and to manipulator intermediate points (auxiliary loading). It is assumed that the manipulator can be presented as a set of compliant links separated by passive or active joints. It proposes a computationally efficient procedure that is able to obtain a non-linear force-deflection relation taking into account the internal and external loadings. It also produces the Cartesian stiffness matrix. This allows to extend the classical stiffness mapping equation for the case of manipulators with auxiliary loading. The results are illustrated by numerical examples.

Dynamic Modeling of an Innovative Piezoelectric Actuator for Minimally Invasive Surgery

1999 ◽  
Author(s):  
Benjamin Edinger ◽  
Mary Frecker ◽  
John Gardner
Keyword(s):  
Minimally Invasive Surgery ◽  
Minimally Invasive ◽  
Dynamic Model ◽  
Invasive Surgery ◽  
Force Measurement ◽  
Equations Of Motion ◽  
Measurement Model ◽  
End Effector ◽  
Simulation Results ◽  
Optimal Driving

Abstract A small piezoelectric inchworm actuator has been designed for use with a monolithic compliant end-effector in minimally invasive surgery procedures. A dynamic model of the inchworm actuator has been developed using SIMULINK. Utilizing the equations of motion for the inchworm actuator, the dynamic characteristics of the piezoelectric stack material, and the known compliance of the gripper, a force measurement model has been developed which extracts resisting force information from the piezoelectric signal. The focus of this paper is on the development of the dynamic model and the results of a simulation study that will be used to develop optimal driving signals for the inchworm actuator. Simulation results include the predicted displacement capabilities and settling time of the inchworm actuator over a range of driving frequencies.

Shape Optimum Design of Robotic Manipulators With Static Performance Criteria

1987 ◽  
Author(s):  
D. A. Saravanos ◽  
J. S. Lamancusa ◽  
H. J. Sommer
Keyword(s):  
Finite Element ◽  
Optimum Design ◽  
Robotic Manipulators ◽  
Performance Criterion ◽  
Performance Criteria ◽  
Robotic Arm ◽  
Mass Ratio ◽  
End Effector ◽  
Vibrational Response ◽  
Static Performance

Abstract The end effector deflections of robotic manipulators may be minimized by optimizing the geometric shape and the dimensions of their links. A multiple posture static performance criterion for the prediction of the shape optimum design is presented. An efficient optimization algorithm is developed for the solution of the problem using finite element modeling to predict the compliance of the robotic arm. The method is applied to an existing robotic arm, and the results demonstrate that simple alterations to the dimensions and the shape of the links can greatly improve, not only the stiffness, but also the stiffness/mass ratio and consequently the vibrational response of the manipulator structure.

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