Design, development and calibration of a robotic wrist force sensor

Muralindran Mariappan (2004) Design, development and calibration of a robotic wrist force sensor. Masters thesis, Universiti Malaysia Sabah.


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With a pressing need for increased productivity and delivery of end products of uniform quality, industries have been focusing on robots to perform variety of manufacturing functions in a more flexible working environment and at lower production cost The usage of robots to circumvent complicated problems and to provide high accuracy is also vastly expanding in many areas such as in medical, aerospace, agriculture, military etc. However, since industries are shifting to a new trend of flexible manufacturing system where robots deal with multiple product manufacturing and varied complex tasks, the degree of freedom (dot) of the robot has significant contribution. For a robot of same type having different number of dot, the cost difference is quite high. Furthermore, the availability of robotic wrist force sensor (wfs) is limited to specific applications only. Hence, the improvement of the dof allows the robot to expand its application sphere and the presence of general-purpose robotic wf5 will allow the robot to perform multiple applications. Such an effort is laid in this thesis where, robot with insufficient dof is improved by adding an additional arm and a general purpose wfs is designed and calibrated to suite any required applications such as screwing, press fitting in assembly, slicing and measurement of surface profile. In this thesis, the structural design of robotic wtS is presented. The wfs design is a modified Maltese cross sensor used on the five axis articulated Fanuc LR-Mate 100i robot The design of a 90-degree additional arm in modifying the roll movement into the yaw movement at the tip of wfs probe so that the robot can to be utilized in tactile sensing and surface exploration is also discussed. The analysis of the wfs beam is performed using singularity function. This analysis identifies the most suitable location to place the strain gauge on the crossbeam of wfs. Simulation of the analysis is also used to study the characteristics of the beam. The system integration is also discussed and software modules are also developed using MATLAB 6.1 and CIMPUCITY HMI software to interface the wfs and the robot to perform the desired tasks. A specially designed calibration kit is used to calibrate the wfs. The calibration study is made for various values of inclination angle, a, surface direction angle, β, reacting force, R, vertical force, Pv and horizontal force, PH. The information a, β and R, obtained from the calibration kit, are fed into a back propagation neural network for calibration. The application of neural network in this thesis overcomes the problems of un-modeled parameters that exist in the calibration equation. The output of the neural network is used to compute the necessary pitch and yaw angles to position the wfs probe normal to unknown surface.

Item Type: Thesis (Masters)
Uncontrolled Keywords: design, calibration, robotic wrist force sensor, product of uniform, lower production cost, manufacturing system
Subjects: T Technology > TJ Mechanical engineering and machinery
Divisions: SCHOOL > School of Engineering and Information Technology
Date Deposited: 28 Jun 2013 16:28
Last Modified: 11 Oct 2017 12:39

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