Preliminary study on end-effector compliance in automated fluid coupling for trains

Abstract

In order to improve train availability and workplace safety standards, the rail industry is keen to modernise maintenance of trains through increased use of Robotic Autonomous Systems (RAS). Our research aims to address the mechanical challenges of automated fluid coupling in future applications of train-fluid servicing. Depending on the intricacy of the servicing RAS, a degree of misalignment will always exist between the robot end-effector and train fluid ports. Compliant end-effectors can generate flexing motions that facilitate misaligned insertions. Present work focuses on understanding the role of passive compliance within the end-effector of our demonstrator train-fluid servicing robot. Physical experiments were performed and using Design of Experiments we identify the effect of end-effector compliance parameters on misaligned insertions. Results show that maximum insertion force and work done increase exponentially with increasing misalignment. Certain arrangements of compliance parameters can significantly improve the coupling performance under misalignments. Nonetheless, forces observed are still too large and our research will continue to develop compliant end-effectors for better automated coupling that will reduce RAS force requirements.