scholarly journals Integrated Trajectory Planning and Sloshing Suppression for Three-Dimensional Motion of Liquid Container Transfer Robot Arm

2015 ◽  
Vol 2015 ◽  
pp. 1-15 ◽  
Author(s):  
Wisnu Aribowo ◽  
Takahito Yamashita ◽  
Kazuhiko Terashima
Keyword(s):  
Trajectory Planning ◽  
Dimensional Space ◽  
Translational Motion ◽  
Three Dimensional ◽  
Joint Space ◽  
Robot Arm ◽  
Task Space ◽  
Robot Wrist ◽  
Point To Point ◽  
Sloshing Suppression

For liquid transfer system in three-dimensional space, the use of multijoint robot arm provides much flexibility. To realize quick point-to-point motion with minimal sloshing in such system, we propose an integrated framework of trajectory planning and sloshing suppression. The robot motion is decomposed into translational motion of the robot wrist and rotational motion of the robot hand to ensure the upright orientation of the liquid container. The trajectory planning for the translational motion is based on cubic spline optimization with free via points that produces smooth trajectory in joint space while it still allows obstacle avoidance in task space. Input shaping technique is applied in the task space to suppress the motion induced sloshing, which is modeled as spherical pendulum with moving support. It has been found through simulations and experiments that the proposed approach is effective in generating quick motion with low amount of sloshing.

Regulation of 3D Human Arm Impedance Through Muscle Co-Contraction

2013 ◽  
Author(s):  
Harshil Patel ◽  
Gerald O’Neill ◽  
Panagiotis Artemiadis
Keyword(s):  
Dimensional Space ◽  
Human Subjects ◽  
Three Dimensional ◽  
Mechanical Impedance ◽  
Dominant Factor ◽  
Robot Arm ◽  
End Point ◽  
Human Arm ◽  
Arm Muscles ◽  
Experimental Trials

Humans have the inherent ability of performing highly dexterous and skillful tasks with their arms, involving maintenance of posture, movement, and interaction with the environment. The latter requires the human to control the dynamic characteristics of the upper limb musculoskeletal system. These characteristics are quantitatively represented by inertia, damping, and stiffness, which are measures of mechanical impedance. Many previous studies have shown that arm posture is a dominant factor in determining the end point impedance on a horizontal (transverse) plane. This paper presents the characterization of the end point impedance of the human arm in three-dimensional space. Moreover, it models the regulation of the arm impedance with respect to various levels of muscle co-contraction. The characterization is made by route of experimental trials where human subjects maintained arm posture while their arms were perturbed by a robot arm. Furthermore, the subjects were asked to control the level of their arm muscles’ co-contraction, using visual feedback of their muscles’ activation, in order to investigate the effect of this muscle co-contraction on the arm impedance. The results of this study show a very interesting, anisotropic increase of arm stiffness due to muscle co-contraction. These results could lead to very useful conclusions about the human’s arm biomechanics, as well as many implications for human motor control-specifically the control of arm impedance through muscle co-contraction.

scholarly journals A unified framework for coordinated multi-arm motion planning

2018 ◽  
Vol 37 (10) ◽  
pp. 1205-1232 ◽  
Author(s):  
Seyed Sina Mirrazavi Salehian ◽  
Nadia Figueroa ◽  
Aude Billard
Keyword(s):  
Moving Objects ◽  
Control Strategies ◽  
Dynamic Control ◽  
Joint Space ◽  
Quadratic Program ◽  
Task Space ◽  
Unified Framework ◽  
External Variable ◽  
Arm Motion ◽  
Point To Point

Coordination is essential in the design of dynamic control strategies for multi-arm robotic systems. Given the complexity of the task and dexterity of the system, coordination constraints can emerge from different levels of planning and control. Primarily, one must consider task-space coordination, where the robots must coordinate with each other, with an object or with a target of interest. Coordination is also necessary in joint space, as the robots should avoid self-collisions at any time. We provide such joint-space coordination by introducing a centralized inverse kinematics (IK) solver under self-collision avoidance constraints, formulated as a quadratic program and solved in real-time. The space of free motion is modeled through a sparse non-linear kernel classification method in a data-driven learning approach. Moreover, we provide multi-arm task-space coordination for both synchronous or asynchronous behaviors. We define a synchronous behavior as that in which the robot arms must coordinate with each other and with a moving object such that they reach for it in synchrony. In contrast, an asynchronous behavior allows for each robot to perform independent point-to-point reaching motions. To transition smoothly from asynchronous to synchronous behaviors and vice versa, we introduce the notion of synchronization allocation. We show how this allocation can be controlled through an external variable, such as the location of the object to be manipulated. Both behaviors and their synchronization allocation are encoded in a single dynamical system. We validate our framework on a dual-arm robotic system and demonstrate that the robots can re-synchronize and adapt the motion of each arm while avoiding self-collision within milliseconds. The speed of control is exploited to intercept fast moving objects whose motion cannot be predicted accurately.

Smooth Trajectory Planning for 3-UPU Parallel Manipulator

2013 ◽  
Vol 464 ◽  
pp. 285-292
Author(s):  
Kambiz Ghaem Osgouie ◽  
Amir Hossein Asfia ◽  
Mohamad Hossein Sadooghi ◽  
Abolfazl Ahmadi Kazemabadi
Keyword(s):  
Trajectory Planning ◽  
Parallel Manipulator ◽  
Optimization Method ◽  
Joint Space ◽  
Optimization Techniques ◽  
Task Space ◽  
Total Execution Time ◽  
B Splines ◽  
Method Optimization ◽  
System Task

Exciting the mechanical resonance mode and vibration caused by non-smooth trajectories can cause some failure in the structure of the robot and its actuators. This work proposes a smooth trajectory planning for 3 degree of freedom (dof) 3-upu parallel manipulator. We have used optimization method to define the smooth trajectory for this robot. In this paper an objective function has been used which contain a term related to the total execution time and a term corresponding to the integral of squared jerk. Some constraints have been applied to the problem as the input of our system. Task space and joint space trajectory are then considered as the output. In this method optimization techniques such as genetic algorithm and fmincon (function of MatLabTM ) have been investigated. Six via points have been considered and B-splines have been used to present kinematic quantities.

Postural Control of Three-Dimensional Prehension Movements

1997 ◽  
Vol 77 (1) ◽  
pp. 452-464 ◽  
Author(s):  
Michel Desmurget ◽  
Claude Prablanc
Keyword(s):  
Postural Control ◽  
Upper Limb ◽  
Three Dimensional ◽  
Joint Space ◽  
Object Orientation ◽  
Task Space ◽  
Movement Onset ◽  
Dynamic Level ◽  
Prehension Movements ◽  
Path Curvature

Desmurget, Michel and Claude Prablanc. Postural control of three-dimensional prehension movements. J. Neurophysiol. 77: 452–464, 1997. This experiment was carried out to test the hypothesis that three-dimensional upper limb movements could be initiated and controlled in the joint space via a mechanism comparing an estimate of the current postural state of the upper arm with a target value determined by one specific inverse static transform converting the coordinates of the object into a set of arm, forearm, and wrist angles. This hypothesis involves two main predictions: 1) despite joint redundancy, the posture reached by the upper limb should be invariant for a given context; and 2) a movement programmed in joint space should exhibit invariant characteristics of the joint covariation pattern as well as a corresponding variable hand path curvature in the task space. To test these predictions, we examined prehension movements toward a cylindrical object presented at a fixed spatial location and at various orientations without vision of the moving limb. Once presented, the object orientation was either kept constant (unperturbed trials) or suddenly modified at movement onset (perturbed trials). Three-dimensional movement trajectories were analyzed in both joint and task spaces. For the unperturbed trials, the task space analysis showed a variable hand path curvature depending on object orientation. The joint space analysis showed that the seven final angles characterizing the upper limb posture at hand-to-object contact varied monotonically with object orientation. At a dynamic level, movement onset and end were nearly identical for all joints. Moreover, for all joints having a monotonic variation, maximum velocity occurred almost simultaneously. For the elbow, the only joint presenting a reversal, the reversal was synchronized with the time to peak velocity of the other joint angles. For the perturbed trials, a smooth and complete compensation of the movement trajectory was observed in the task space. At a static level the upper limb final posture was identical to that obtained when the object was initially presented at the orientation following the perturbation. This result was particularly remarkable considering the large set of comfortable postures allowed by joint redundancy. At a dynamic level, the joints' covariation pattern was updated to reach the new target posture. The initial synergies were not disrupted by the perturbation, but smoothly modified, the different joints' movements ending nearly at the same time. Taken together, these results support the hypothesis that prehension movements are initiated and controlled in the joint space on the basis of a joint angular error vector rather than a spatial error vector.

scholarly journals Task Space Trajectory Planning for Robot Manipulators to Follow 3-D Curved Contours

Electronics ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 1424
Author(s):  
Juhyun Kim ◽  
Maolin Jin ◽  
Sang Hyun Park ◽  
Seong Youb Chung ◽  
Myun Joong Hwang
Keyword(s):  
Trajectory Planning ◽  
Control Parameters ◽  
Spline Method ◽  
Task Space ◽  
Scaling Method ◽  
Time Scaling ◽  
Shoe Manufacturing ◽  
End Effectors ◽  
Point To Point ◽  
Robotic Tasks

The demand for robots has increased in the industrial field, where robots are utilized in tasks that require them to move through complex paths. In the motion planning of a manipulator, path planning is carried out to determine a series of the positions of robot end effectors without collision. Therefore, it is necessary to carry out trajectory planning to determine position, velocity, and acceleration over time and to control an actual industrial manipulator. Although several methods have already been introduced for point-to-point trajectory planning, a trajectory plan which moves through multiple knots is required to allow robots to adapt to more complicated tasks. In this study, a trajectory planning based on the Catmull–Rom spline is proposed to allow a robot to move via several points in a task space. A method is presented to assign intermediate velocities and time to satisfy the velocity conditions of initial and final knots. To optimize the motion of the robot, a time-scaling method is presented to minimize the margin between the physical maximum values of velocity and acceleration in real robots and the planned trajectory, respectively. A simulation is then performed to verify that the proposed method can plan the trajectory for moving multiple knots without stopping, and also to check the effects of control parameters. The results obtained show that the proposed methods are applicable to trajectory planning and require less computation compared with the cubic spline method. Furthermore, the robot follows the planned trajectory, and its motion does not exceed the maximum values of velocity and acceleration. An experiment is also executed to prove that the proposed method can be applied to real robotic tasks to dispense glue onto the sole in the shoe manufacturing process. The results from this experiment show that the robot can follow the 3-D curved contour in uniform speed using the proposed method.

Path constraints on point-to-point arm movements in three-dimensional space

Neuroscience ◽  
1986 ◽  
Vol 17 (2) ◽  
pp. 313-324 ◽  
Author(s):  
F. Lacquaniti ◽  
J.F. Soechting ◽  
S.A. Terzuolo
Keyword(s):  
Dimensional Space ◽  
Three Dimensional ◽  
Arm Movements ◽  
Path Constraints ◽  
Point To Point ◽  
Three Dimensional Space

scholarly journals Point Cloud Registration Based on Multiparameter Functional

Mathematics ◽  
2021 ◽  
Vol 9 (20) ◽  
pp. 2589
Author(s):  
Artyom Makovetskii ◽  
Sergei Voronin ◽  
Vitaly Kober ◽  
Aleksei Voronin
Keyword(s):  
Dimensional Space ◽  
Three Dimensional ◽  
Point Clouds ◽  
Autonomous Driving ◽  
Geometric Transformation ◽  
Icp Algorithm ◽  
Registration Algorithm ◽  
Closed Point ◽  
Partial Overlap ◽  
Point To Point

The registration of point clouds in a three-dimensional space is an important task in many areas of computer vision, including robotics and autonomous driving. The purpose of registration is to find a rigid geometric transformation to align two point clouds. The registration problem can be affected by noise and partiality (two point clouds only have a partial overlap). The Iterative Closed Point (ICP) algorithm is a common method for solving the registration problem. Recently, artificial neural networks have begun to be used in the registration of point clouds. The drawback of ICP and other registration algorithms is the possible convergence to a local minimum. Thus, an important characteristic of a registration algorithm is the ability to avoid local minima. In this paper, we propose an ICP-type registration algorithm (λ-ICP) that uses a multiparameter functional (λ-functional). The proposed λ-ICP algorithm generalizes the NICP algorithm (normal ICP). The application of the λ-functional requires a consistent choice of the eigenvectors of the covariance matrix of two point clouds. The paper also proposes an algorithm for choosing the directions of eigenvectors. The performance of the proposed λ-ICP algorithm is compared with that of a standard point-to-point ICP and neural network Deep Closest Points (DCP).

scholarly journals Point-to-Point trajectory planning of flexible redundant robot manipulators using genetic algorithms

Robotica ◽  
2002 ◽  
Vol 20 (3) ◽  
pp. 269-280 ◽  
Author(s):  
Shigang Yue ◽  
Dominik Henrich ◽  
W. L. Xu ◽  
S. K. Tso
Keyword(s):  
Genetic Algorithms ◽  
Trajectory Planning ◽  
Robot Manipulators ◽  
Joint Space ◽  
Redundant Robot ◽  
Flexible Links ◽  
Gas Kinematics ◽  
Quintic Polynomial ◽  
Point Motion ◽  
Point To Point

The paper focuses on the problem of point-to-point trajectory planning for flexible redundant robot manipulators (FRM) in joint space. Compared with irredundant flexible manipulators, a FRM possesses additional possibilities during point-to-point trajectory planning due to its kinematics redundancy. A trajectory planning method to minimize vibration and/or executing time of a point-to-point motion is presented for FRMs based on Genetic Algorithms (GAs). Kinematics redundancy is integrated into the presented method as planning variables. Quadrinomial and quintic polynomial are used to describe the segments that connect the initial, intermediate, and final points in joint space. The trajectory planning of FRM is formulated as a problem of optimization with constraints. A planar FRM with three flexible links is used in simulation. Case studies show that the method is applicable.

FORCE-UNCONSTRAINED POSES OF THE 3-PRR AND 4-PRR PLANAR PARALLEL MANIPULATORS

2005 ◽  
Vol 29 (4) ◽  
pp. 617-628 ◽  
Author(s):  
Flavio Firmani ◽  
Ron P. Podhorodeski
Keyword(s):  
Parallel Manipulator ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Parallel Manipulators ◽  
Task Space ◽  
Planar Parallel Manipulator ◽  
Order Polynomial ◽  
Position And Orientation ◽  
Planar Parallel Manipulators ◽  
Three Dimensional Space

Force-unconstrained (singular) poses of the 3-PRR planar parallel manipulator (PPM), where the underscore indicates the actuated joint, and the 4-PRR, a redundant PPM with an additional actuated branch, are presented. The solution of these problems is based upon concepts of reciprocal screw quantities and kinematic analysis. In general, non-redundant PPMs such as the 3-PRR are known to have two orders of infinity of force-unconstrained poses, i.e., a three-variable polynomial in terms of the task-space variables (position and orientation of the mobile platform). The inclusion of redundant branches eliminates one order of infinity of force-unconstrained configurations for every actuated branch beyond three. The geometric identification of force-unconstrained poses is carried out by assuming one variable for each order of infinity. In order to simplify the algebraic procedure of these problems, the assumed or “free” variables are considered to be joint displacements. For both manipulators, an effective elimination technique is adopted. For the 3-PRR, the roots of a 6th-order polynomial determine the force-unconstrained poses, i.e., surfaces in a three dimensional space defined by the task-space variables. For the 4-PRR, a 64th-order polynomial determines curves of force-unconstrained poses in the same dimensional space.

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