The strength of the individual paper fiber bonds (IPFB) is the key parameter which determines the mechanical quality of paper hand sheets. Currently, most of the strength measurements are still done on hand-sheet level because of the absence of high throughput IPFB strength measurement tools. Micro and Nanosystems research group of Tampere University of Technology recognized the demand for an IPFB characterization system and built a microrobotics platform. However, the current configuration of the platform is not able to rotate the microgripper which limits the measurements such as Z-directional bond breaking and shear mode bond breaking. Moreover, this configuration is not capable of dealing with twisted fibers. This thesis addresses these problems and introduces addition of two more degrees of rotation to the current platform. This modification of microrobotic platform will enable the bond strength measurement of IPFBs in desired pure modes which will enhance the paper fiber scientist`s understanding of IPFBs breaking process.
Bond strength measurement with the current platform provides data that is a combination of normal and shear forces which is not desired. After the modifications provided by this thesis, the microrobotic platform will be able to separate the shear force and the normal force during shear mode bond breaking.
In the Z-directional bond strength measurement, it is essential to know which fiber is on the top whereas the platform does not fulfill this requirement. The rotation of the microgripper and thus, the fibers will reveal the orientation of the IPFBs.
Moreover, the rotation of the microgripper enables the user to untwist the twisted fibers by rotating from one end while the other end is fixed with another microgripper.
Forward kinematics of the modified system is calculated through Matlab and compared with the real system. The errors between the ideal system and real system are reduced significantly by modifying the parameters in the overall transformation matrix which ensures that the modified microrobotic platform is now capable of solving all three problems discussed above. Maximum errors are decreased 90.65% (from 107 micrometers to 10 micrometers) at the X-axis, 82.47% (from 97 micrometers to 17 micrometers) at the Y-axis and 87.17% (from 195 micrometers to 25 micrometers) at the Z-axis
