Tim Detert

Motor Positioning and Drive Train Design for a 3-DOF Robotic Structure

This paper introduces a systematic approach to the drive train design and positioning of motors for 3 DOF robotic arms for a new kind of parallel-kinematic manipulator. After a short introduction into the state of the art, the methodology and main considerations are presented and applied to gain a set of principle solutions for possible drive-trains for every link. Combining this principle solutions, nine concepts for the robotic arm are developed.

Cognitive Self-Optimization in Industrial Assembly

Modern day production has to overcome a polylemma – the gaps between economies of scale and scope as well as between economies of plan and value. Due to shorter product lifecycles and a rising demand of customization, flexibility and adaptability of assembly processes will become key elements for a sustainable success of industrial production in high-wage countries. Self-optimization as presented in this paper has been identified as one major contributor to the enhancement of this flexibility and adaptability. After a short introduction of the historical background, the specifics of the application of self-optimization to assembly are discussed using its meta model. In the end, two application examples are presented to illustrate its industrial deployment.

Improving the Accuracy of a Multi-Arm-Robot-System by Parameter Identification of the Single Arms

Based on a novel handling concept, the reconfigurable modular multi-arm robot system PARAGRIP is able to handle objects with six DOF by including them into a parallel kinematic structure. The properties of this repeatedly new created parallel structure can be adjusted by appropriate choice of the grasping-and base points to gain optimal performances for a given task. As kinematic parameters determine the transmission behavior and properties of the structure, deviations in the kinematic control model induce positioning errors of the object. In this work, the reduction of these positioning errors is investigated by parameter identification of the implemented kinematic parameters for a single robotic arm. After deriving the kinematic relations of the system, the pose is measured using an external referencing system. Meaningful kinematic parameters are identified and it is shown that the accuracy of each arm can be increased significantly.

Reconfiguration Analysis and Motion Planning of a Novel Reconfigurable Mobile Manipulator Torso

A novel 2-RER reconfigurable parallel mechanism (ReConBot) considered as the flexible torso of the mobile manipulator is proposed. This paper deals with the analysis of reconfiguration, kinematics, and motion planning. The ReConBot is composed of straight bar-shape base and moving platforms and two metamorphic kinematic chains (MKC) consisted of a revolute (R) joint, a planar (E) joint, and an R joint in sequence. Firstly, mobility and reconfiguration analysis discuss the conditions and mutual mode transition rules of 12 possible configuration states. And then, the kinematics model covers all states with Cartesian coordinate and axis/angle representations. Whats more, the motion planning following the rules of the mode transition is explained and illustrated together with a case study. Furthermore, the method of handling the transition at singularity position is discussed. Finally, the robotic system and its experiments verify the correctness of the theoretical analysis and the validation of reconfiguration rules.

Cooperating Robot Force Control for Positioning and Untwisting of Thin Walled Components

Geometric deformations in large thin walled components such as airplane shells caused by gravitational influences have to be compensated before assembly. The research objective is to develop a metrology assisted robot based assembly system that detects deformations and compensates them through force controlled movements of the robots. This paper describes the development of a cooperating robot force control for three industrial robots. The control algorithm uses a numerical optimization to take into account the strong mechanical coupling of the robots by the handled component.

Reconbot: A Reconfigurable Rescue Robot Composed of Serial-Parallel Hybrid Upper Humanoid Body and Track Mobile Platform

The mobility analysis of a 2-URU parallel mechanism (PM) using the screw theory and its novel application for constructing reconfigurable mobile robot are the main focus of this paper. By taking advantage of the singularity positions, the PM can reconfigure into different mobility configurations, which enable the robot to multi-mode collaborative locomotion and cooperative serial-parallel hybrid manipulation. Integrating these properties, a novel reconfigurable rescue robot called Reconbot composed of a track platform, a reconfigurable 2-URU PM with an equal offset in its two universal joints and two 7-DoF serial arms is proposed. The PM consisted of two offset URU branch chains and two platforms serves as dexterous upper body with base platform mounted on the track platform and two arms attached to the moving platform. The Reconbot can deform into folding compact state, serial two-leg state, parallelogram five-bar linkage state, etc.

Cognition-Enhanced, Self-optimizing Assembly Systems

Due to shorter product lifecycles and a rising demand for customization, flexibility and adaptability of assembly processes will become key elements in achieving sustainable success of industrial production in high-wage countries. Cognition-enhanced self-optimization as presented in this chapter has been identified as one major contributor to the enhancement of this flexibility and adaptability. The proposed approach to realize cognition-enhanced self-optimization for assembly systems in a broad range of application domains is to integrate dynamic behavior allowing reactions on disturbances and unforeseen events by dynamically adapting the target objectives of internal control loops. Unlike the approach of traditional closed control loops in which target objectives of an optimization process are determined in advance, this approach defines goal functions as dynamically adaptable throughout the process. The chapter concludes with two application examples—one dealing with the assembly of large-scale components (airplane structures) and the other with small component assembly (micro-optical elements)—presented to illustrate the industrial deployment of self-optimization for assembly tasks.

Kybernetische Ansätze in der Produktionstechnik

Kybernetische Ansatze sind seit langem ein wichtiger Teil der Produktionstechnik. Die Regelungstechnik – als Teil der Kybernetik – ist die Voraussetzung dafur, dass Zustandsgrosen in Produktionsmaschinen gefuhrt oder konstant gehalten werden, wahrend Storgrosen ohne menschlichen Eingriff kompensiert werden. Klassische regelungstechnische Ansatze gehen davon aus, dass sich Regelstrecken mit einer festgelegten Struktur von Ubertragungsfunktionen beschreiben lassen. Im Hinblick auf Automatisierungslosungen fur kundenindividuelle Produkte ist diese Voraussetzung jedoch nicht mehr gegeben. In diesem Zusammenhang wird der Begriff der Selbstoptimierung fur Systeme verwendet, „die in der Lage sind, auf Grund geanderter Eingangsbedingungen oder Storungen eigenstandige („endogene“) Veranderungen ihres inneren Zustands oder ihrer Struktur vorzunehmen“ (Schmitt et al., Selbstoptimierende Produktionssysteme. In: Integrative Produktionstechnik fur Hochlohnlander. Springer, 2011, S. 750). Der Schritt von der klassischen Regelungstechnik zur Selbstoptimierung besteht somit darin, das Zielsystem mithilfe von modellbasierten oder kognitiven Methoden anzupassen. Im Exzellenzcluster „Integrative Produktionstechnik fur Hochlohnlander“ und in flankierenden Projekten wird erforscht, wie selbstoptimierende Produktionssysteme auf unterschiedlichen Ebenen konzipiert werden konnen. Der Beitrag zeigt anhand ausgewahlter Demonstratoren die Potenziale der Selbstoptimierung in der Produktionstechnik auf und macht dadurch deutlich, dass die IT-gestutzte Kybernetik auch zukunftig ein wichtiges Hilfsmittel in der Produktionstechnik darstellen wird.

Kinematic Calculation for modular reconfigurable cooperating Robotic Systems

The field of reconfigurable and cooperative robotics is attracting increasingly widespread attention in industry. The reasons for this are the many advantages of such systems over traditional fixed configuration single arm robots, such as their adaptability to changing tasks and superior stiffness properties. This paper presents a solution scheme for a computational calculation of the joint variables and Jacobian of arbitrarily configured modular cooperating robots for the task of object integrated manipulation. The system architecture is defined and a calculation procedure which takes into consideration possible kinematic redundancy as well as actuator constraints is implemented and then validated on a representative example.