Sequential Time-Optimal Algorithm for Extended Path Tracking Problem

2020 ◽  
Vol 142 (8) ◽  
Author(s):  
Gábor Csorvási ◽  
István Vajk
Keyword(s):  
Degrees Of Freedom ◽  
Optimal Algorithm ◽  
Real Life ◽  
Path Tracking ◽  
Robotic Arm ◽  
Tracking Problem ◽  
Six Degrees Of Freedom ◽  
Time Optimal ◽  
Path Tracking Algorithm ◽  
Extended Path

Abstract This paper presents a fast and easily implementable path tracking algorithm for robots. Usually, for a path tracking problem, the goal is to move the robot on a predefined path, while the joint velocities and accelerations are kept within their limits. This paper deals with the extended case, constraining the forces applied to the objects at the manipulator. First, a problem with a special set of constraints is presented, and a sequential solver method is formulated. The presented sequential solver algorithm has significant computational benefits compared to the direct transcription approach. Then, a practical example is introduced where the proposed algorithm can be applied. At last, the algorithm is validated by real-life experimental results with a six degrees-of-freedom robotic arm.

scholarly journals Ship-to-Ship State Observer Using Sensor Fusion and the Extended Kalman Filter

2019 ◽  
Vol 141 (4) ◽  
Author(s):  
Sondre Sanden Tørdal ◽  
Geir Hovland
Keyword(s):  
Kalman Filter ◽  
Sensor Fusion ◽  
Extended Kalman Filter ◽  
Relative Motion ◽  
Degrees Of Freedom ◽  
Load Transfer ◽  
Real Life ◽  
Fusion Algorithm ◽  
Six Degrees Of Freedom ◽  
Motion Estimate

In this paper, a solution for estimating the relative position and orientation between two ships in six degrees-of-freedom (6DOF) using sensor fusion and an extended Kalman filter (EKF) approach is presented. Two different sensor types, based on time-of-flight and inertial measurement principles, were combined to create a reliable and redundant estimate of the relative motion between the ships. An accurate and reliable relative motion estimate is expected to be a key enabler for future ship-to-ship operations, such as autonomous load transfer and handling. The proposed sensor fusion algorithm was tested with real sensors (two motion reference units (MRS) and a laser tracker) and an experimental setup consisting of two Stewart platforms in the Norwegian Motion Laboratory, which represents an approximate scale of 1:10 when compared to real-life ship-to-ship operations.

Integrating laser profile sensor to an industrial robotic arm for improving quality inspection in manufacturing processes

2020 ◽  
pp. 095440622094255
Author(s):  
Toufik Al Khawli ◽  
Muddasar Anwar ◽  
Dongming Gan ◽  
Shafiqul Islam
Keyword(s):  
Degrees Of Freedom ◽  
Ground Truth ◽  
Calibration Procedure ◽  
Robotic Arm ◽  
Manufacturing Processes ◽  
Quality Inspection ◽  
Six Degrees Of Freedom ◽  
Tool Positioning ◽  
Sharp Object ◽  
Laser Profile

This paper investigates the integration of laser profile sensor to an industrial robotic arm for automating the quality inspection in manufacturing processes that requires a manual labour intensive work. The aim was to register the measurements from a laser profile sensor mounted on a six degrees-of-freedom robot with respect to the robot base frame. The registration is based on a six degrees-of-freedom calibration, which is an essential step for several automated manufacturing processes that require high level of accuracy in tool positioning and alignment on one hand, and quality inspection systems that require flexibility and accurate measurements on the other hand. The investigation compromises of two calibration procedures namely the calibration using a sharp object and the planar constraints. The solution of the calibration procedures estimated from both iterative and optimization solvers is thoroughly discussed. By implementing a simulation platform that generates virtual data for the two procedures with additional levels of noise, the six-dimensional poses are estimated and compared to the ground truth. Finally, an experimental test using a laser profile from Acuity mounted on Mitsubishi RV-6SDL manipulator is presented to investigate the measurement accuracy with four estimated laser poses. The calibration procedure using a sharp object shows the most accurate simulation and experimental results under the effect of noise.

scholarly journals Inverse Kinematics Data Adaptation to Non-Standard Modular Robotic Arm Consisting of Unique Rotational Modules

2021 ◽  
Vol 11 (3) ◽  
pp. 1203
Author(s):  
Štefan Ondočko ◽  
Jozef Svetlík ◽  
Michal Šašala ◽  
Zdenko Bobovský ◽  
Tomáš Stejskal ◽  
...  
Keyword(s):  
Inverse Kinematics ◽  
Degrees Of Freedom ◽  
Structural Changes ◽  
Kinematic Chain ◽  
Building Blocks ◽  
Robotic Arm ◽  
Six Degrees Of Freedom ◽  
Coordinate Vector ◽  
Mathematical Equations ◽  
The Individual

The paper describes the original robotic arm designed by our team kinematic design consisting of universal rotational modules (URM). The philosophy of modularity plays quite an important role when it comes to this mechanism since the individual modules will be the building blocks of the entire robotic arm. This is a serial kinematic chain with six degrees of freedom of unlimited rotation. It was modeled in three different environments to obtain the necessary visualizations, data, measurements, structural changes measurements and structural changes. In the environment of the CoppeliaSim Edu, it was constructed mainly to obtain the joints coordinates matching the description of a certain spatial trajectory with an option to test the software potential in future inverse task calculations. In Matlab, the model was constructed to check the mathematical equations in the area of kinematics, the model’s simulations of movements, and to test the numerical calculations of the inverse kinematics. Since the equipment at hand is subject to constant development, its model can also be found in SolidWorks. Thus, the model’s existence in those three environments has enabled us to compare the data and check the models’ structural designs. In Matlab and SolidWorks, we worked with the data imported on joints coordinates, necessitating overcoming certain problems related to calculations of the inverse kinematics. The objective was to compare the results, especially in terms of the position kinematics in Matlab and SolidWorks, provided the initial joint coordinate vector was the same.

scholarly journals A New 6 DOF Robotic Arm with Linkage Motion Mechanism and Actuators Placed in Base

2016 ◽  
Vol 5 (1) ◽  
pp. 35
Author(s):  
Mohsen Shahhosseini ◽  
Rambod Rastegari ◽  
Roozbeh Abbasi
Keyword(s):  
Mechanism Design ◽  
Degrees Of Freedom ◽  
Robotic Arm ◽  
Linkage Mechanism ◽  
Performance Simulation ◽  
Motion Mechanism ◽  
Six Degrees Of Freedom ◽  
Bevel Gears ◽  
Controller Performance ◽  
Special Case

<p>We examined mechanism design and kinematic simulation of a new six degrees of freedom (DOF) robotic arm with rotational joints and a linkage motion mechanism. In the design, a parallel linkage mechanism, accompanied by an additional set of bevel gears, was used to create the desired motion for all six links along with transfer of all actuators to the robot’s base to reduce the mass of most of the arms. These changes resulted in reduction of the torque required for joints 1, 2, and 3. Using this parallel mechanism ensures dependence to motion links and creates a special case for the control of the robot and more rigidity against unwanted movement. Initially, we examined mechanism design methods for a parallel linkage mechanism and considered methods for application in an operational robot. In the next step, we determined the kinematic relationships that were established between the robot’s actuators and joints spaces due to the use of this mechanism. Then, we developed an example of the robot’s function in a performance simulation. The simulation results indicated that the mechanism and controller performance were acceptable.</p>

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