Yanjun Yang

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Using a laparoscope-holding robot in minimally invasive surgery has been shown to improve surgeons’ efficiency and operation safety. However, controlling the robot can increase surgeons’ cognitive load. Therefore, a suitable interface is critical to ease the control task and reduce surgeons’ workload. A foot interface for commanding the robot is common, with two control strategies possible: Decoupled control only allows a single Cartesian axis actuation, known as decoupled commands. Hybrid control enables both a single axis and multiple axes actuation, known as coupled commands. This paper aims to find the most suitable control strategy for foot interfaces by validating two common assumptions in the literature for a laparoscope manipulation task: 1. Decoupled control is believed to have better final laparoscopic view orientation predictability, and 2. Hybrid control is assumed to be more efficient in manipulating the laparoscope. Results from a user study with 11 surgeons and surgeon trainees show that the decoupled control indeed has better predictability than the hybrid control. However, the result does not support assumption 2 with both approaches equally efficient. In addition, we analyze the interface usage patterns and safety when choosing between the coupled and decoupled commands using two surgery-like tasks in a simulator. The results show that decoupled commands are preferred for small adjustments, and coupled commands are preferred for larger motions. No obvious correlation between control safety and command selection is found. Based on the assumptions validation and usage patterns study, a guideline for foot interface control strategy selection is provided. The experiment protocol can be modified for other human-robot interaction studies in surgical and industry applications.