Preparation for Capturing Human Skills during Tooling Tasks Using Redundant Markers and Instrumented Tool

2016 ◽  
Vol 842 ◽  
pp. 293-302
Author(s):  
Phan Gia Hoang ◽  
H. Asif ◽  
Domenico Campolo
Keyword(s):  
Motion Capture ◽  
Force Control ◽  
Material Handling ◽  
End Effector ◽  
Continuous Contact ◽  
Human Skills ◽  
User Skills ◽  
Dependent Tasks ◽  
Kinematic Information ◽  
Experienced User

In recent years, robots have found extensive applications in automating repetitive, defined, position dependent tasks such as painting and material handling. However, continuous contact type tasks (such as finishing, deburring and grinding) that require both position and force control are still carried out manually by skilled labor. Majorly, because it is difficult to program experienced user skills in a robotic setup without having clear knowledge of underlying model used by the operators. In this paper we present a preparation for capturing human operator’s dynamics using an instrumented hand-held tool and a motion capture setup. We first present the design of an instrumented tool and later present a method for reliably capturing kinematics using redundant markers removing effects of marker occlusions, and effect of gravity caused by the tool's mass. Kinematic information is used for deriving the forces/torques on the tool end effector.

Robotic force control for deburring using an active end effector

Robotica ◽  
1989 ◽  
Vol 7 (4) ◽  
pp. 303-308 ◽  
Author(s):  
G. M. Bone ◽  
M. A. Elbestawi
Keyword(s):  
Control System ◽  
Force Control ◽  
Pid Controller ◽  
Closed Loop ◽  
Least Squares Method ◽  
Closed Loop Control ◽  
End Effector ◽  
Loop Control ◽  
Positioning Errors ◽  
Force Control System

SUMMARYAn active force control system for robotic deburring based on an active end effector is developed. The system utilizes a PUMA-560 six axis robot. The robot's structural dynamics, positioning errors, and the deburring cutting process are examined in detail. Based on ARMAX plant models identified using the least squares method, a discrete PID controller is designed and tested in real-time. The control system is shown to maintain the force within l N of the reference, and reduce chamfer depth errors to 0.12 mm from the 1 mm possible without closed-loop control.

Dynamic Analysis of Handling Compliant Sheet-Metal Blanks

2007 ◽  
Author(s):  
Gene Y. Liao
Keyword(s):  
Sheet Metal ◽  
Stiffness Matrix ◽  
Material Handling ◽  
Equations Of Motion ◽  
Time Integration ◽  
Nonlinear Finite Element ◽  
Time Varying ◽  
End Effector ◽  
Part Quality ◽  
Element Technique

Automating material handling of flexible sheet-metal blanks in stamping process requires attention due to its significant impact on product quality and productivity. This paper investigated the capability of a fully dynamic and nonlinear finite element technique in developing virtual material handling process of compliant sheet-metal blanks subject to time varying movability conditions. The technique used explicit time integration to avoid the formulation of stiffness matrix by a direct integration of the equations of motion. The influence of holding end-effector layout scheme and movability conditions on the final part quality was investigated.

On the Problem of Constrained Path Following For Manipulators

1988 ◽  
Vol 110 (4) ◽  
pp. 443-448
Author(s):  
A. Sankaranarayanan ◽  
M. Vidyasagar
Keyword(s):  
Collision Avoidance ◽  
Force Control ◽  
Robot Manipulator ◽  
Sufficient Conditions ◽  
Path Following ◽  
Necessary And Sufficient Conditions ◽  
End Effector ◽  
Circular Contour ◽  
Necessary And Sufficient

Force Control involves moving the end-effector of a robot manipulator on the surface of an object while ensuring that no other part of the manipulator collides with the object. Suppose C is a given contour to be followed. If the end-effector can move between two points a and b on C while meeting the collision avoidance requirement, we can say that a path exists between a and b. We begin by considering a planar manipulator and a circular contour and derive the necessary and sufficient conditions for a path to exist between a pair of points. By extending these ideas, sufficient conditions are derived for a noncircular contour. The advantages of a (kinematically redundant) 3-link planar manipulator over a 2-link manipulator are pointed out. Finally, we consider spatial manipulators and derive the necessary and sufficient conditions for the case where the contour lies on the surface of a sphere.

Hybrid Position/Force Control for a RRR 3-DoF Manipulator

2011 ◽  
Vol 48-49 ◽  
pp. 589-592 ◽  
Author(s):  
Shi Xiang Tian ◽  
Sheng Ze Wang
Keyword(s):  
Force Control ◽  
Free Space ◽  
High Performance ◽  
Degree Of Freedom ◽  
End Effector ◽  
Robot Trajectory ◽  
Simulation Results ◽  
Trajectory Following ◽  
Three Degree Of Freedom

In this paper, a novel hybrid position/force controller has been proposed for a three degree of freedom (3-DOF) of robot trajectory following that is required to switch between position and force control. The whole controller consists of two components: a positional controller and a force controller. Depending on whether the end-effector is in free space or in contact with the environments during work, the two subcontrollers run simultaneously to guide the manipulator tracking in free space and constraint environments. After the principle and stability of the controller are briefly analyzed, simulation results verify that the proposed controller attains a high performance.

scholarly journals Is Power Grasping Contact Continuous or Discrete?

2013 ◽  
Vol 29 (5) ◽  
pp. 554-562 ◽  
Author(s):  
Todd C. Pataky ◽  
Greg P. Slota ◽  
Mark L. Latash ◽  
Vladimir M. Zatsiorsky
Keyword(s):  
Force Control ◽  
Continuous Contact ◽  
Local Maxima ◽  
External Forces ◽  
Power Grasp ◽  
Anatomical Constraints ◽  
Pushing And Pulling

During power grasp, the number of local force maxima reflects either the central nervous system’s preferential use of particular hand regions, or anatomical constraints, or both. Previously, both bimodal and trimodal force maxima have been hypothesized for power grasp of a cylindrical handle. Here we measure the number of local force maxima, with a resolution of 4.8°, when performing pushing and pulling efforts in the plane perpendicular to the cylinder’s long axis. Twelve participants produced external forces to eight targets. The number of contacts was defined as the number of local maxima exceeding background variance. A minimum of four and a maximum of five discrete contacts were observed in all subjects at the distal phalanges and metacarpal heads. We thus reject previous hypotheses of bimodal or trimodal force control for cylindrical power grasping. Since we presently observed only 4–5 contacts, which is rather low considering the hand’s kinematic flexibility in the flexion plane, we also reject hypotheses of continuous contact, which are inherent to current grasping taxonomy. A modification to current grasping taxonomy is proposed wherein power grasp contains separate branches for continuous and discrete contacts, and where power and precision grasps are distinguished only by grasp manipulability.

scholarly journals Subdividing the Beat: Auditory and Motor Contributions to Synchronization

2009 ◽  
Vol 26 (5) ◽  
pp. 415-425 ◽  
Author(s):  
Janeen D. Loehr ◽  
Caroline Palmer
Keyword(s):  
Motion Capture ◽  
Music Performance ◽  
Sensory Information ◽  
Auditory Information ◽  
Finger Motion ◽  
Motor Production ◽  
Synchronization Accuracy ◽  
Kinematic Information

THE CURRENT STUDY EXAMINED HOW AUDITORY AND kinematic information influenced pianists' ability to synchronize musical sequences with a metronome. Pianists performed melodies in which quarter-note beats were subdivided by intervening eighth notes that resulted from auditory information (heard tones), motor production (produced tones), both, or neither. Temporal accuracy of performance was compared with finger trajectories recorded with motion capture. Asynchronies were larger when motor or auditory sensory information occurred between beats; auditory information yielded the largest asynchronies. Pianists were sensitive to the timing of the sensory information; information that occurred earlier relative to the midpoint between metronome beats was associated with larger asynchronies on the following beat. Finger motion was influenced only by motor production between beats and indicated the influence of other fingers' motion. These findings demonstrate that synchronization accuracy in music performance is influenced by both the timing and modality of sensory information that occurs between beats.

Modeling and Optimization of End Effector Layout for Handling Compliant Sheet Metal Parts

2000 ◽  
Vol 123 (3) ◽  
pp. 473-480 ◽  
Author(s):  
D. Ceglarek ◽  
H. F. Li ◽  
Y. Tang
Keyword(s):  
Sheet Metal ◽  
Material Handling ◽  
Design Stage ◽  
End Effector ◽  
Industrial Practice ◽  
Modeling And Optimization ◽  
Sheet Metal Stamping ◽  
Sheet Metal Parts ◽  
Metal Stamping ◽  
Compliant Parts

Material handling of compliant parts is one of the most critical and underresearched problems in the sheet metal stamping industry. The fundamental shortcoming of currently studied material handling systems for sheet metal stamping is the lack of analysis of its impact on part dimensional quality and production throughput. This paper addresses this problem by development of a generic methodology for modeling and optimization of part holding end-effector layout in order to minimize part dimensional deformation during handling operations. The methodology extends the design of “N-2-1” fixturing layout by adding part movability conditions. It considers part CAD model, handling direction and motion kinematic parameters to determine the best end effector layout. This methodology is realized by integrating FEM part and loading modeling with the optimization algorithm. It can be implemented into the design stage of a stamping line so that the trial and error process, which is current industrial practice, can be greatly shortened and the production throughput increased. Experimental results verify the proposed part holding end-effector layout methodology.

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