Miniature medical robot navigates over a beating heart

Citation

Bloss, R. (2012), "Miniature medical robot navigates over a beating heart", Industrial Robot, Vol. 39 No. 4. https://doi.org/10.1108/ir.2012.04939daa.001

Miniature medical robot navigates over a beating heart

Article Type: Mini features From: Industrial Robot: An International Journal, Volume 39, Issue 4

Researchers at the Carnegie Mellon University Robotics Institute have developed an endoscopic robot that can explore the surface of a patient’s beating heart (Figure 1). Called the HeartLander, the robot’s main function is to safely reach places on the heart to inject drugs that are needed without requiring major surgical incisions in the patient.

Figure 1 The HeartLander robot shown on a heart mock up

The robot consists of a long tube like structure that enters the patient. External to the patient is the controller/display, a vacuum pump and two actuator motors. The head of the robot consists of two units each with a vacuum cup, one with a tracking sensor, the other with the injection system. The robot is connected to the outside with vacuum tubes, drive wires to move the cups and the injector actuator (Figure 2). Each head is 5.5 mm×8 mm×8 mm and weighs only 0.3 g.

Figure 2 Cutaway diagram of the HeartLander robot head to show structure

The robot moves by alternating vacuum to each of the cups and inching along by pushing and pulling on the drive wires. One cup grips while the other cup moves then vacuum is switched and the action repeated until the robot head reaches the desired location. The operator follows the robot head movement on a display which recreates the movements based on feedback from the tracking sensor.

The drug injection system safely stores the needle while in motion. The 27-gauge needle is housed in the front robot unit. When the robot reaches the injection location the needle is extended into the heart. The injection distance can be preset mechanically to a range of 1-5 mm. The drug is forced through the injection system with an external syringe.

The vacuum cups are each 6 mm in diameter and 3.5 mm deep. The edge is lined with a thin latex strip to create a good vacuum seal the epicarduium of the heart. The tether is 650 mm in length. The tether is passive and requires not electrical energy inside the body cavity. All of the power requirements are external to the patient. The drive wires are each powered by a separate stepping motor. After the injection is completed, the robot retracts in the same manner as deployment. As a fail-safe feature, if necessary the robot can be manually extracted by pulling on the wire/tubing bundle.

Richard Bloss