Force sensing linear rolling guides

Force measurement capabilities in machine tools enable process monitoring and process control. Thus, force measurement is an essential enabler for industry 4.0 applications in cutting processes. Researchers have dealt with integrating force sensors into different machine tool components such as spindle slides, spindle units, clamping systems, and tool holders. This work aims to investigate the potential of expanding force measurement capabilities to linear rolling guides. The paper presents a force measurement approach based on strain gauge sensors applied on the guide carriages. The approach is investigated experimentally on a single carriage as well as on a linear-axis test rig. It is shown that measurement and distinction of two force directions at each carriage under the presence of disturbance torques is possible. The achievable sensitivity is sufficient to detect misalignment of the guide rails. However, force sensitivity is not sufficient for process monitoring yet. Moreover, disturbances such as time varying constraint forces, preload variation, and roller circulation lead to major challenges for force measurement by this component. Thus, sophisticated signal processing will be inevitable for reliable measurement of process forces.