Accelerometer Based Absolute Positioning for a Miniature In-Vivo Surgical Robot

摘要

The development and adoption of minimally invasive surgery (MIS) in the 1990's was a pivotal advancement in general surgery. MIS techniques allow surgeries to be performed through a few small incisions instead of one large incision. Laparoendoscopic Single-Site Surgery (LESS) has recently gained interest as an MIS procedure [1]. Many relatively simple surgical tasks are currently performed using LESS, but there are factors that limit the use of LESS in more advanced procedures, such as colon resection. To apply LESS to more complex surgical procedures, new tools must be developed to overcome these limitations. Miniature in vivo surgical robots have been developed that can address these problems and provide an alternative method to convert open abdominal procedures to a minimally invasive method. Miniature in vivo surgical robots are inserted into the peritoneal cavity through the navel where, once inserted, need to be able provide exact position feedback to the surgeon. Currently, incremental optical encoders attached to motor shafts are used to provide quick relative feedback, but do not provide absolute angle information. It only provides joint angle information relative to where it was when the robot was initially powered on. Currently, a visual homing routine is used to sync the global position of the robot with the information from the encoders, but if the robot were to lose power and have to reinitiate while performing surgery, the global position of the robot would be lost and the homing routine would have to be performed. This presents a problem with a visual homing routing. If the robot is in the abdominal cavity it is really hard to see what position the robot is in. This can be fixed by replacing the visual homing method with a sensor system to measure the global absolute position of the robot. This additional system will also provide critical redundancy to the position feedback system.