Control of the interaction of a gantry robot end effector with the environment by the adaptive behaviour of its joint drive actuators

The thesis examines a way in which the performance of the robot electric actuators can be precisely and accurately force controlled where there is a need for maintaining a stable specified contact force with an external environment. It describes the advantages of the proposed research, which eliminates the need for any external sensors and solely depends on the precise torque control of electric motors. The aim of the research is thus the development of a software based control system and then a proposal for possible inclusion of this control philosophy in existing range of automated manufacturing techniques.The primary aim of the research is to introduce force controlled behaviour in the electric actuators when the robot interacts with the environment, by measuring and controlling the contact forces between them. A software control system is developed and implemented on a robot gantry manipulator to follow two dimensional contours without the explicit geometrical knowledge of those contours. The torque signatures from the electric actuators are monitored and maintained within a desired force band. The secondary aim is the optimal design of the software controller structure. Experiments are performed and the mathematical model is validated against conventional Proportional Integral Derivative (PID) control. Fuzzy control is introduced in the software architecture to incorporate a sophisticated control. Investigation is carried out with the combination of PID and Fuzzy logic which depend on the geometrical complexity of the external environment to achieve the expected results

Robot Manipulators

Robot manipulators are developing more in the direction of industrial robots than of human workers. Recently, the applications of robot manipulators are spreading their focus, for example Da Vinci as a medical robot, ASIMO as a humanoid robot and so on. There are many research topics within the field of robot manipulators, e.g. motion planning, cooperation with a human, and fusion with external sensors like vision, haptic and force, etc. Moreover, these include both technical problems in the industry and theoretical problems in the academic fields. This book is a collection of papers presenting the latest research issues from around the world

Fuzzy PID control of a two-link flexible manipulator

For a flexible manipulator system, the unwanted vibrations deteriorate usually the performance of the system due to the coupling of large overall motion and elastic vibration. This paper focuses on the active vibration control of a two-link flexible manipulator with piezoelectric materials. The multi flexible body dynamics (MFBD) model of the two-link flexible manipulator attached with piezoelectric sensors and actuators is established firstly. Based on the absolute nodal coordinate formulation (ANCF), the motion equations of the manipulator system are derived and motion process and dynamic responses of the system are simulated. According to the time varying feature of system, a fuzzy PID controller is developed to depress the vibration. This controller can tune control gains online accommodating to the variation of the system. Control results obtained by the fuzzy PID control and the conventional PID control indicate that the fuzzy PID controller can effectively suppress the elastic vibration of the manipulator system and performs better than the conventional PID controller

Performance of modified jatropha oil in combination with hexagonal boron nitride particles as a bio-based lubricant for green machining

This study evaluates the machining performance of newly developed modified jatropha oils (MJO1, MJO3 and MJO5), both with and without hexagonal boron nitride (hBN) particles (ranging between 0.05 and 0.5 wt%) during turning of AISI 1045 using minimum quantity lubrication (MQL). The experimental results indicated that, viscosity improved with the increase in MJOs molar ratio and hBN concentration. Excellent tribological behaviours is found to correlated with a better machining performance were achieved by MJO5a with 0.05 wt%. The MJO5a sample showed the lowest values of cutting force, cutting temperature and surface roughness, with a prolonged tool life and less tool wear, qualifying itself to be a potential alternative to the synthetic ester, with regard to the environmental concern

Elasto-geometrical modeling and calibration of robot manipulators: Application to machining and forming applications

International audienceThis paper proposes an original elasto-geometrical calibration method to improve the static pose accuracy of industrial robots involved in machining, forming or assembly applications. Two approaches are presented respectively based on an analytical parametric modeling and a Takagi-Sugeno fuzzy inference system. These are described and then discussed. This allows to list the main drawbacks and advantages of each of them with respect to the task and the user requirements. The Fuzzy Logic model is used in a model-based compensation scheme to increase significantly the robot static pose accuracy in a context of incremental forming application. Experimental results show the efficiency of the Fuzzy Logic model while minimizing development and computational resources

MODELLING AND CONTROL OF MULTI-FINGERED ROBOT HAND USING INTELLIGENT TECHNIQUES

Research and development of robust multi-fingered robot hand (MFRH) have been going on for more than three decades. Yet few can be found in an industrial application. The difficulties stem from many factors, one of which is that the lack of general and effective control techniques for the manipulation of robot hand. In this research, a MFRH with five fingers has been proposed with intelligent control algorithms. Initially, mathematical modeling for the proposed MFRH has been derived to find the Forward Kinematic, Inverse Kinematic, Jacobian, Dynamics and the plant model. Thereafter, simulation of the MFRH using PID controller, Fuzzy Logic Controller, Fuzzy-PID controller and PID-PSO controller has been carried out to gauge the system performance based parameters such rise time, settling time and percent overshoot

Design and construction of a portable force-reflecting manual controller for teleoperation systems

A man-machine system called teleoperator system has been developed to work in hazardous environments such as nuclear reactor plants. Force reflection is a type of force feedback in which forces experienced by the remote manipulator are fed back to the manual controller. In a force-reflecting teleoperation system, the operator uses the manual controller to direct the remote manipulator and receives visual information from a video image and/or graphical animation on the computer screen. This thesis presents the design of a portable Force-Reflecting Manual Controller (FRMC) for the teleoperation of tasks such as hazardous material handling, waste cleanup, and space-related operations. The work consists of the design and construction of a prototype 1-Degree-of-Freedom (DOF) FRMC, the development of the Graphical User Interface (GUI), and system integration. Two control strategies - PID and fuzzy logic controllers are developed and experimentally tested. The system response of each is analyzed and evaluated. In addition, the concept of a telesensation system is introduced, and a variety of design alternatives of a 3-DOF FRMC are proposed for future development