Combined pose-wrench and state machine representation for modeling Robotic Assembly Skills

Wahrburg, Arne; Zeiss, Stefan; Matthias, Björn; Peters, Jan; Ding, Hu

doi:10.1109/iros.2015.7353471

Cited by 12 publications

(7 citation statements)

References 12 publications

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“…27 Examples include languages for pick and place, 28 assembly, 29 control, 12 and perception. 30 A commonly used design for current assembly languages is to rely on action and skill libraries, e.g., as suggested by Huckaby et al 31 or by Wahrburg et al 32 These provide a layered architecture and rely on domain abstractions for handling complex operations and control flow. The advantage of the design is that users can create programs using existing primitives and experts can add new complex primitives as long as they comply with the framework's conditions, as shown by both Thomas et al 12 and Bøgh et al 33 Our framework employs a similar structure.…”

Section: Robot Programmingmentioning

confidence: 99%

Modelling reversible execution of robotic assembly

Laursen¹,

Ellekilde²,

Schultz³

2018

Robotica

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SUMMARYProgramming robotic assembly for industrial small-batch production is challenging; hence, it is vital to increase robustness and reduce development effort in order to achieve flexible robotic automation. A human who has made an assembly error will often simply undo the process until the error is undone and then restart the assembly. Conceptually, robots could do the same. This paper introduces a programming model that enables robot assembly programs to be executed in reverse. We investigate the challenges in running robot programs backwards and present a classification of reversibility characteristics. We demonstrate how temporarily switching the direction of program execution can be an efficient error recovery mechanism. Moreover, we demonstrate additional benefits arising from supporting reversibility in an assembly language, such as increased code reuse and automatically derived disassembly sequences. As a default approach to reversibility, we use program inversion and statement-level inversion of commands, but with a novel override option providing alternative sequences for asymmetric reverse actions. To efficiently program for this model, this paper introduces a new domain-specific language, SCP-RASQ (Simple C++ Reversible Assembly SeQuences). In initial experiments, where 200 consecutive assemblies of two industrial cases were performed, 18 of 22 errors were corrected automatically using only the trial-and-error capabilities that come from reverse execution.

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Section: Robot Programmingmentioning

confidence: 99%

Modelling reversible execution of robotic assembly

Laursen¹,

Ellekilde²,

Schultz³

2018

Robotica

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“…In [10], "Robotic Assembly Skills" are defined with the purpose of establishing a clear interface with higher level logic. Other, more formal, definition can be found in [6], with the aim of developing a manipulation primitives based control system.…”

Section: Related Workmentioning

confidence: 99%

“…More recently, the problem of snap-fitting has been subject of attention. A manipulator is supposed to assemble an object that requires the application of a significant amount of force in order to 'snap' the parts together [16], [10].…”

Section: Related Workmentioning

confidence: 99%

Bimanual folding assembly: Switched control and contact point estimation

Almeida

Vina

Karayiannidis

2016

2016 IEEE-RAS 16th International Conference on Humanoid Robots (Humanoids)

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Abstract-Robotic assembly in unstructured environments is a challenging task, due to the added uncertainties. These can be mitigated through the employment of assembly systems, which offer a modular approach to the assembly problem via the conjunction of primitives. In this paper, we use a dual-arm manipulator in order to execute a folding assembly primitive. When executing a folding primitive, two parts are brought into rigid contact and posteriorly translated and rotated. A switched controller is employed in order to ensure that the relative motion of the parts follows the desired model, while regulating the contact forces. The control is complemented with an estimator based on a Kalman filter, which tracks the contact point between parts based on force and torque measurements. Experimental results are provided, and the effectiveness of the control and contact point estimation is shown.

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“…by formulating position-force commands, such as 'rotate to level', 'rotate to insert' [9], or concatenating sensorimotor primitives [10], [11], using human inspired recipes [12] or formulating elementary actions in the task frame [13]. The idea of elementary skills has still gained some interest in recent works [14], [15]. However, the ingenuity of finding the primitives that apply best in certain situations and parameterizing them often means a considerable engineering effort, leaving the cognitive performance to the programmer and not to the system.…”

Section: Introductionmentioning

confidence: 99%

Contact Skill Imitation Learning for Robot-Independent Assembly Programming

Scherzinger

Roennau

Dillmann

2019

2019 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS)

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Robotic automation is a key driver for the advancement of technology. The skills of human workers, however, are difficult to program and seem currently unmatched by technical systems. In this work we present a data-driven approach to extract and learn robot-independent contact skills from human demonstrations in simulation environments, using a Long Short Term Memory (LSTM) network. Our model learns to generate error-correcting sequences of forces and torques in task space from object-relative motion, which industrial robots carry out through a Cartesian force control scheme on the real setup. This scheme uses forward dynamics computation of a virtually conditioned twin of the manipulator to solve the inverse kinematics problem. We evaluate our methods with an assembly experiment, in which our algorithm handles part tilting and jamming in order to succeed. The results show that the skill is robust towards localization uncertainty in task space and across different joint configurations of the robot. With our approach, non-experts can easily program force-sensitive assembly tasks in a robot-independent way.

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Combined pose-wrench and state machine representation for modeling Robotic Assembly Skills

Cited by 12 publications

References 12 publications

Modelling reversible execution of robotic assembly

Modelling reversible execution of robotic assembly

Bimanual folding assembly: Switched control and contact point estimation

Contact Skill Imitation Learning for Robot-Independent Assembly Programming

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