An Automated Traction Measurement Platform and Empirical Model for Evaluation of Rolling Micropatterned Wheels

Colonoscopy is the leading preventative procedure for colorectal cancer. The traditional tool used for this procedure is an endoscope, which can cause patient discomfort, pain and fear of the procedure. There has been a movement to develop a robotic capsule colonoscope (RCC) in an attempt to mitigate these drawbacks and increase procedure popularity. An RCC is a capsule robot that propels itself through the colon as opposed to being pushed, like a traditional endoscope. In this study, an overview of an in vivo RCC is given, followed by the introduction of a mobility method for an RCC using micropatterned polydimethylsiloxane (PDMS). The design of a three degree-of-freedom automated traction measurement (ATM) platform for quantitative evaluation of the mobility method is presented. An empirical model for traction force as a function of slip ratio, robot speed, and weight for micropatterned PDMS on synthetic tissue is developed using data collected from the ATM platform. The model is then used to predict traction force at different slip ratios, speeds, and weights, and is verified experimentally. The average normalized root-mean-square error (NRMSE) between the empirical model and the data used to develop the model is 1.1% (min 0.0024%, max 4.2%). The average NRMSE between the traction force predicted by the model and the data used to verify the prediction is 1.8% (min 0.020%, max 8.6%). Understanding how model parameters influence tread performance will improve future RCC mobility systems and aid in the development of analytical models, leading to more optimal designs.