Description:
Sustainable manufacturing assessment is meant to ensure that products are manufactured such that negative environmental impacts are reduced by conserving energy and managing the use of natural resources as well as ensuring economical soundness for the process. The main objective of this work is to introduce sustainable development methodology/models for manufacturing processes. For this purpose, the paper utilizes background data, develops a computer model and presents detailed case studies. This paper will identify and adopt key performance indicators (KPIs) and utilize these to assess the sustainability of extrusion process and their designs. Different manufacturing parameters such as material types, product specifications and manufacturing tools are considered in the process of measuring sustainability. The proposed computer model is verified with data obtain from actual aluminium extrusion plants.
Description:
Sustainable manufacturing assessment is meant to ensure that products are manufactured such that negative environmental impacts are reduced by conserving energy and managing the use of natural resources as well as ensuring economical soundness for the process. The main objective of this work is to introduce sustainable development methodology/models for manufacturing processes. For this purpose, the paper utilizes background data, develops a computer model and presents detailed case studies. This paper will identify and adopt key performance indicators (KPIs) and utilize these to assess the sustainability of extrusion process and their designs. Different manufacturing parameters such as material types, product specifications and manufacturing tools are considered in the process of measuring sustainability. The proposed computer model is verified with data obtain from actual aluminium extrusion plants.
Description:
A circolimacon positive displacement machine is driven by a lima on mechanism, but the profiles of its rotor and housing are circular arcs. As such, its design models are different from those of the lima on-to-lima on machines, whose profiles are cut to the limacon equations. For the benefit of the reader the paper starts with a brief background on the general geometric aspects of the limacon fluid processing technology. However the focus is then turned to the circolimacon machine, where its design parameters are introduced and geometric models are proposed to assist with the design process. Also, a computational inverse design model has been employed to work out a set of congruent geometric parameters to meet certain design requirements. Case studies are presented at the end of the paper to give the reader a numerical perspective on the design process of this class of positive displacement machines.
Description:
It is central to the control of manipulators to calculate the set/sets of joint-displacements which correspond to a given spatial pose (position and orientation) of the end-effector. This problem, which is referred to as the inverse position problem, represents one of the most difficult mathematical challenges in the field of robotics, particularly when performed for calibrated robots (or robots with general structures). In such cases, closed form solutions are too impractical to implement and iterative solutions suffer from numerical singularities. In the present work a procedure is introduced to obtain multiple inverse position solutions for serial robotic structures. For calibrated robots, the procedure involves a simple iterative technique designed to ensure fast convergence and eliminate the occurrence of singularity. However, inverse position solutions for spherical-wrist manipulators will be obtained in a straight-forward non-iterative fashion. A published kinematic notation, referred to as the phi -model, was used to develop the system equations.
Description:
Accurate use of robots in an off-line programming mode is only possible through a proper calibration procedure. In this procedure, the end-effector is made to move along a set of known spatial poses where the positional errors are to be measured and employed in mathematical models. The models are subsequently solved for the manipulator dimensions (geometric parameters) using suitable regression techniques. Calibration is usually performed using either aggregate or independent-axis models. While the aggregate models result in all the system parameters being worked out simultaneously, the independent-axis models are meant to work out the geometric particulars of each joint-axis individually. In the present work, the independent-axis technique is used for the analysis with new mathematical models proposed to overcome the drawbacks of the existing methods. Moreover, the techniques employed here result in the prediction of transmission error functions and the modelling of the joint motion dependencies. This is a new concept in the field of robot calibration. Finally, the models proposed have been used to calibrate an ASEA IRB/L6 robot and the results are reported at the end of the paper.
Description:
Accurate use of robots in an off-line programming mode is only possible through a proper calibration procedure. In this procedure, the end-effector is made to move along a set of known spatial poses where the positional errors are to be measured and employed in mathematical models. The models are subsequently solved for the manipulator dimensions (geometric parameters) using suitable regression techniques. Calibration is usually performed using either aggregate or independent-axis models. While the aggregate models result in all the system parameters being worked out simultaneously, the independent-axis models are meant to work out the geometric particulars of each joint-axis individually. In the present work, the independent-axis technique is used for the analysis with new mathematical models proposed to overcome the drawbacks of the existing methods. Moreover, the techniques employed here result in the prediction of transmission error functions and the modelling of the joint motion dependencies. This is a new concept in the field of robot calibration. Finally, the models proposed have been used to calibrate an ASEA IRB/L6 robot and the results are reported at the end of the paper.
Description:
This paper presents a proposed adaptive technique for nonholonomic wheeled mobile robot (NWMR) using the sliding-mode control (SMC) method. The proposed control system based on the backstepping kinematic controller and PI sliding mode dynamic control. With an adaptive fuzzy logic to adjust adaptation gain of SMC for trajectory tracking control of nonholonomic mobile robot. Parametric and nonparametric uncertainties of mobile robot can be solved by using the proposed control which take advantages of stability and robustness in sliding mode control. The adaptation gain of SMC is adjusted by using Mamdani type inference system with adaptive tuning algorithm, which improves the adaptability for uncertainness and eliminate input chattering of the SMC. The stability and convergence of the control system are proved using Lypanouve criteria, and the comparison of the proposed controller with the other controllers ensures the validity and superiority of my own controller
Description:
This paper presents an expert system for the life cycle assessment of die-casting process. The system is built around a robust database of the die-casting process parameters. The sustainability of die-casting is measured using performance indicators, namely investment cost of machines and equipment, operating cost of machines, and energy-related carbon emissions. The methodology of developing an expert system first uses MATLAB function (combivec) to generate alternate process plans thereafter it uses a multi-criteria decision-making method as technique for order of preference by similarity to ideal solution (TOPSIS) for selecting the best feasible process plan. Results show that the proposed approach can compare alternate process plans using sustainability performance indicators for selecting the best feasible option. An illustrative example is presented in this paper for demonstrating how to implement the proposed expert system
Description:
Forward and inverse kinematics operations are important in the operational space control of mechanical manipulators. In case of a parallel manipulator, the forward kinematics function relates the joint variables of the active joints to the position of end-effector. This paper finds analytically forward kinematics function by exploiting the position-closure property. Using the proposed function along with the analytical Jacobian presented in the literature, the forward and the inverse kinematics blocks are formulated for a prospective operational space control scheme. Finally, an example is presented for a 3-RPR robot.