Bengt Lennartson

A Constructive Cooperative Coevolutionary Algorithm Applied to Press Line Optimisation

Simulation-based optimisation often considers computationally expensive problems. Successfully optimising such large scale and complex problems...

A faster collision detection method applied on a sheet metal press line

Geometrical collision detection is a time and resource consuming simulation task. In order to decrease time and resources, a general method...

A faster collision detection method applied on a sheet metal press line

Geometrical collision detection is a time and resource consuming simulation task. In order to decrease time and resources, a general method has bee...

A new Camera Model and Algorithms for higher Accuracy and better Convergence in Vision-based Pose Calculations

This paper presents novel strategies for better calibration and pose calculations of a system for determining the pose, i.e. position and...

A new Camera Model for Higher Accuracy Pose Calculations

A position and orientation (pose) measurement system is being developed. The system, called PosEye, is based on a camera and by using the informati...

A Virtual Real-Time Model for Control Software Development : applied on a Sheet-Metal Press Line

An efficient algorithm for press line optimisation

Automated manufacturing processes such as automotive tandem press lines include time dependent complex control functions. All motions and critical...

Analysis and evaluation of a general camera model

A versatile General Camera Model, GCM, has been developed, and is described in detail. The model is general in the sense that it can capture both...

Automated Generation of Discrete Event System Simulation Models for Flexible Automation

Flexible automation cells with rapid product changes are an important competitive advantage for industries today. These cells can increase a...

Automation of laser metal deposition for the manufacture of fully dense structures

Automation of Robotized Laser Metal-Wire Deposition

Camera Modelling and Calibration - with Applications

Constructive cooperative coevolution for large-scale global optimisation

This paper presents the Constructive Cooperative Coevolutionary ( C3C3 ) algorithm, applied to continuous large-scale global optimisation problems....

Constructive cooperative coevolutionary optimisation for interacting production stations

Optimisation of the control function for multiple automated interacting production stations is a complex problem, even for skilled and experienced...

Continuous-, discrete- and sampled-data- H∞ˆž control - a unified framework

We present a unified and general framework for H∞-control in both continuous time, discrete time and combinations of these. The general result is a...

Control Design for Automation of Robotized Laser Metal-Wire Deposition

In this paper a novel approach towards automation of robotized laser metal-wire deposition (RLMwD) is described. The RLMwD technique is being...

Efficient geometrical simulation and virtual commissioning performed in stamping

In order to  perform efficient geometrical simulation and virtual commissioning in stamping, three fields are investigated namely: simulation...

Emissivity compensated spectral pyrometry for varying emissivity metallic measurands

A novel method for converting electromagnetic spectral radiance information into emperature measurements is presented. It allows for varying spectr...

Emissivity compensated spectral pyrometry-algorithm and sensitivity analysis

In order to solve the problem of non-contact temperature measurements on an object with varying emissivity, a new method is herein described and...

Freeform Fabrication using Laser Metal-wire Deposition

General Time Synchronisation Method for PLC Programs Aiming at Virtual Verification and Development

The latest state-of-the-art Computer Aided Production Engineering (CAPE) simulation technology offers OPC integration for PLC verification. A...

Goal-Oriented Process Plans in a Multiagent System for Plug & Produce

This article presents a framework for Plug & Produce that makes it possible to use configurations rather than programming to adapt a manufacturing...

Height control of laser metal-wire deposition based on iterative learning control and 3D scanning

Laser Metal-wire Deposition is an additive manufacturing technique for solid freeform fabrication of fully dense metal structures. The technique is...

Improved Constructive Cooperative Coevolutionary Differential Evolution for Large-Scale Optimisation

The Differential Evolution (DE) algorithm is widely used for real-world global optimisation problems in many different domains. To improve DE's...

Increased stability in laser metal wire deposition through feedback from optical measurements

Robotized laser metal-wire deposition is a fairly new technique being developed at University West in cooperation with Swedish industry for solid...

Low order sampled data H∞ control using the delta operator and LMIs

A procedure for H ∞ optimization of low order controllers for discrete-time and sampled-data systems is presented in this paper. Generally, low...

Low order sampled-data H∞ control

A method for obtaining low order sampled-data H∞ controllers is presented. The method is mainly based on a parametric static feedback controller fo...

Methods for Reliable Simulation-Based PLC Code Verification

Simulation based PLC code verification is a part of virtual commissioning, where the control code is verified against a virtual prototype of an...

Model based feedback control of gas tungsten arc welding : An experimental study

In order to obtain high structural integrity and joint performance in welding a transient heat conduction model has been utilized to design a model...

Model order reduction methods applied to a welding model

A  finite element representation modelling transient heat conduction of gas tungsten arc welding of stainless steel is used to evaluate different...

Modeling and Optimization of Hybrid Systems for the Tweeting Factory

In this paper, a predicate transition model for discrete-event systems is generalized to include continuous dynamics, and the result is a modular...

Modelling and Simulation for Feedback Control of Welding

Multi-objective constructive cooperative coevolutionary optimization of robotic press-line tending

This article investigates multi-objective optimization of the robot trajectories and position-based operation-coordination of complex multi-robot...

Off-Line Optimisation of Complex Automated Production Lines : Applied on a Sheet-Metal Press Line

This paper presents a successful off-line optimisation case study of a sheet-metal press line for the automotive industry. The proposed off-line...

Off-Line Simulation of Advanced Stereo Vision Welding Applications

Optimisation of Interacting Production Stations using a Constructive Cooperative Coevolutionary Approach

Simulation-based optimisation carries the burden of computationally expensive fitness calculations. It is very often used to tackle large-scale...

Optimised Control of Sheet Metal Press Lines

Determining the control parameters for sheet metal press lines is a large scale and complex optimisation problem. These control parameters determin...

Productivity/energy optimisation of trajectories and coordination for cyclic multi-robot systems

The coordination of cyclic multi-robot systems is a critical issue to avoid collisions but also to obtain the shortest cycle-time. This paper...

Resistance based iterative learning control of additive manufacturing with wire

This paper presents successful feed forward control of additive manufacturing of fully dense metallic components. The study is a refinement of form...

Resistance measurements for control of laser metal wire deposition

A method for controlling robotized laser metal wire deposition online by electrical resistance metering is proposed. The concept of measuring the...

Role of fixture forces on distortion in gas tungsten arc welding : An experimental and modelling approach

Simulation and experiments show that the fixture clamping force has a significant influence on the structural integrity of a welded workpiece. This...

Sampled-data H∞ˆž-control for time-varying hybrid systems

This paper presents sampled-data H∞ˆž-control of linear mixed continuous-time and discrete-time systems, including a mix of continuous-time and...

Sheet-Metal Press Line Parameter Tuning using a Combined DIRECT and Nelder-Mead Algorithm

It is a great challenge to obtain an efficient algorithm for global optimisation of nonlinear, nonconvex and high dimensional objective functions....

Simulation based optimization of a sheet-metal press line

An off-line optimization of a sheet-metal press line is performed with improved production performances, both in terms of increased production rate...

Simulation for Design of Automated Welding

This paper describes a promising approach where simulations were used in the design of real-time control for automated welding. A finite element...

Simulation-based Time and Jerk Optimisation for Robotic Press Tending

Increased production rate and robot motion smoothness in a sheet metal press line are essential. Smooth robot motions avoid unplanned production...

Time-synchronised hardware-in-the-loop simulation - Applied to sheet-metal press optimisation

This paper presents an off-line process parameter tuning method, focussing on complex control functions for automated manufacturing systems. The...

Toward efficient geometrical simulation and virtual commissioning in stamping

Towards stable high-speed metal-wire deposition, Part I: Parameter study

Towards stable high-speed metal-wire deposition, Part II: Automatic deposition using feedback control