  Clinicians require substantial training and experience to become comfortable
with steering Intracardiac echocardiography (ICE) catheter to localize and
measure the area of treatment to watch for complications while device catheters
are deployed in another access. Thus, it is reasonable that a robotic-assist
system to hold and actively manipulate the ICE catheter could ease the workload
of the physician. Existing commercially-available robotic systems and research
prototypes all use existing commercially available ICE catheters based on
multiple tendon-sheath mechanism (TSM). To motorize the existing TSM-based ICE
catheter, the actuators interface with the outer handle knobs to manipulate
four internal tendons. However, in practice, the actuators are located at a
sterile, safe place far away from the ICE handle. Thus, to interface with
knobs, there exist multiple coupled gear structures between two, leading to a
highly nonlinear behavior (e.g. various slack, elasticity) alongside hysteresis
phenomena in TSM.
  Since ICE catheters are designed for single use, the expensive actuators need
to be located in a safe place so as to be reusable. Moreover, these actuators
should interface as directly as possible with the tendons for accurate tip
controls. In this paper, we introduce a separable ICE catheter robot with four
tendon actuation: one part reusable and another disposable. Moreover, we
propose a practical model and calibration method for our proposed mechanism so
that four tendons are actuated simultaneously allowing for precise tip control
and mitigating issues with conventional devices such as dead-zone and
hysteresis with simple linear compensation. We consider an open-loop controller
since many available ICE catheters are used without position-tracking sensors
at the tip due to costs and single use
