Christian Löchte

Methods for Implementing Compensation Strategies in Micro Production Systems Supported by a Simulation Approach

Customers demands for highest product quality and lowest product costs and the use of rapidly changing technologies are the challenges for industrial companies. To cope with these challenges production processes need to be more effective. This also applies to the production of innovative micro products. However, the micro production has so far not adopted the advantages of established organization and quality strategies in production systems. Therefore, this article proposes three compensations methods which integrate quality strategies into a micro production system (MPS) with respect to the special needs of producing micro products. The aim is to balance quality errors against each other throughout the production process. This is illustrated by the example of micro assembly. This example uses a simulation approach to show the integration of the afore mentioned compensation methods in combination with a quality strategy. It allows a dynamic view of the effect of balancing errors during the whole production process.

A parallel kinematic concept targeting at more accurate assembly of aircraft sections

This article is concerned with the kinematics for flexible and precise assembly systems for big and heavy parts, e.g. parts of plane fuselages or wings. The hypothesis of this article is that the common 3- PPP S Tripod (which is a current industrial solution to the problem) may be replaced by a 6-S P S parallel kinematic. In difference to many other parallel kinematic machines, the part which has to be assembled is used itself as the end effector platform in this concept. On the part and on the floor, there is a generic grid of fixation points, which gives the possibility for (re)configuration and adaption to suit particular requirements. This article compares the transmission of drive errors in order to evaluate the transmission of alignment increments. This criterion is used for an optimization that searches for a kinematic configuration that outperforms the Tripod systems. It is shown that there is a considerable number of configurations which are superior to the Tripod system. Based on these insights, it is concluded that there is potential for the improvement of current systems through multi-objective optimization.

Novel form-flexible handling and joining tool for automated preforming

Abstract The production rates of carbon fiber reinforced plastic (CFRP) parts are rising constantly which in turn drives research to bring a higher level of automation to the manufacturing processes of CFRP. Resin transfer molding (RTM), which is seen as a production method for high volumes, has been accelerated to a high degree. However, complex net-shape preforms are necessary for this process, which are widely manually manufactured. To face these challenges a new concept for the manufacturing of carbon fiber preforms with a form-flexible gripping, draping and joining end-effector is presented and discussed. Furthermore, this paper investigates the application of this concept, describes the initial build-up of a demonstrator, focusing on material selection and heating technology, and discusses test results with the prototype. This prototype already validates the feasibility of the proposed concept on the basis of a generic preform geometry. After a summary, this paper discusses future in-depth research concerning the concept and its application in more complex geometries.

TRoBS — a biological inspired robot

This contribution presents a biological inspired robot, called Trunk Robot Braunschweig (TRoBS). The structural shape of the robot is motivated by a trunk mechanism, where the robot is actuated by NiTi shape memory alloy (SMA) wires, placed according to the agonist-antagonist principle of muscles. The robot has a modular structure, the single segments are connected by compliant joints, whose arrangement permit a variable degree of freedom (DoF) depending on the number of segments. The joints have a similar working principle as revolute joints. In order to show the functionality of the robot, the mechanical structure, the benefits of compliant joints as well as a method of kinematic modelling are presented. Another focus is placed on the actuation principle. The robot is actuated by SMA wires formed like springs, which provide advantages in design as well as in control aspects. Due to the high modularity of the mechanism, the robot is arbitrarily extendable and so adoptable for several applications.

Design Methodology for a Compliant Binary Actuated Parallel Mechanism with Flexure Hinges

This paper discusses the further development of a binary parallel manipulator named BaPaMan1 (Binary Actuated PArallel MANipulator), which is aimed at the improvement of the structural stiffness and allows task-adaptation. BaPaMan1 is a three DOF spatial parallel robot which comprises flexure hinges and Shape Memory Alloy (SMA) actuators to achieve a low-cost design, well suited for easy operation applications. Measurements have shown that this comes at the cost of poor structural stiffness and end effector accuracy. To counter these issues BaPaMan2 and BaPaMan3 have been developed and are elaborated within this work. During the design phase, an empirical FEA was used to improve the flexure hinge performance, in which relations between several design parameters and the stiffness of the entire system were analyzed. Finally, task-adaptation was achieved using a developed design methodology and parametric CAD model for BaPaMan3, which take advantage of deduced stiffness influencing equations.