Researchers in medical robotics have taken interest into using magnetic resonance imaging (MRI) as a guiding imaging modality for robotic interventions. MRI has several advantages compared to other imaging modalities. For example, it does not use ionizing radiation and it is able to achieve high contrast imaging in soft tissue. However, the strong and varying magnetic field that the MRI-scanner generates puts stringent material requirements on the robot that operates within. To ensure patient safety and prevent imaging artefacts, electronics and ferromagnetic materials should not be present within the MRI-bore. This poses a challenge to the development of sensors and actuators for the purpose of assisting with interventions inside the MRI-scanner.
To accurately control the robot, it is important to have position feedback from a position sensor. An MR Safe solution is the use of fibre optic sensors. However, these sensors are costly and not compact. Instead, this project looks into the options to use pneumatics to make a fully MR Safe position sensor for robotic applications.
In this project an empirical approach was taken to design and fabricate a pneumatic position sensor. Static characterisation of the sensor shows that the position sensor is not yet accurate enough to be applied in medical robotics. Therefore, to explore possible future directions, a pneumatic position encoder has also been designed and fabricated.