Redundant Force Sensing for Cooperatively-controlled Surgical Robot

Unmet Need:
Many cooperatively controlled surgical robots incorporate force/torque sensors as the main input for the human interactions controlling robot motion. Force/torque sensors are susceptible to many modes of failure due to accidents, misuse, or hazards in the environment. Sensors can also generate false measurements from temperature change, electrical noise, or mechanical deformation. In situations where measurements are inaccurate, it is possible the surgical robot will react in an unexpected and possibly unsafe manner. These types of problems present high risk scenarios where any undesirable motion of the surgical instrument controlled by a robot may cause severe injury or even a patient’s death.
 
Technology Overview:
Hopkins researchers have developed novel features that improve a surgical robot’s stability and safety. Because the efficiency and reliability of the primary force/torque sensor is critical to ensuring stringent control and safety requirements in surgical applications, the inventors focused on introducing additional force/torque sensors in different locations to mitigate complications stemming from the failure of one single primary sensor.
 
Specific to cooperative control of force/torque sensing, several new elements with a single interface were engineered into the robot’s design. First, additional force/torque sensors act as a consistency check on the primary force/torque sensor and are used to cross-check the force and frequency values to determine if a failure has occurred. Second, in the event of robot arm collision, the motion, direction, force and contact point on the robot arm can be estimated. Third, operator interactions can be detected through frequency analysis to verify that the surgeon is properly holding an instrument (attached to the robot) without using a pedal or a button. Fourth, it provides improved stability and protection against user hand tremor.

Stage of Development:
Surgical robot prototype is available.

Publications:
N/A
 

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