Camera Thermals Solution

Background & Introduction

• Vicarious Surgical's camera system takes a novel approach to surgical imaging. 

  The design is meant to provide users with a 360 degree stereoscopic view of the working environment while providing ample illumination for a clear picture of the surgeon’s location of interest. In order to accomplish this, the main subassembly of the camera consists of a cylindrical enclosure which contains a circuit board. This board, along with a number of other components, is populated with two image sensors (‘cameras’) and two LEDs.

• Users are permitted to manually adjust focus distance and LED brightness, along with the ability to articulate the camera in space to achieve visualization of the target defect. 

  One drawback of producing light and recording images within the distal assembly itself, rather than using fiber optic technology, is the generation of significant amounts of heat within the patient’s abdomen.

• Camera thermals has been a challenge of the Vicarious Surgical system for many years. Efforts have been made to address the problem from various avenues. These include reducing necessary power consumption, adding passive cooling geometry, altering enclosure materials, etc. to name a few, but none of these designs proved to demonstrate a large enough cooling effect.

Design & Development

• After it was apparent that a more complex cooling solution was going to be required, I began work developing thermal simulations using COMSOL. These simulations were meant to evaluate different concepts which implemented an active cooling approach.

• After refining the thermal model to a point where myself and my team was happy with the results, we began prototyping machined assemblies to test the concept in a bench top assembly.

  
  

• Bench top testing pointed to success! Since initial results appeared promising, we proceeded with further testing and used this data to compare to simulations.

• After running a number of tests and analyzing their data, the testing results were nearly identical to the thermal model. This indicated that the model was useful for future prototype development and could be used as a more efficient means of heat transfer optimization.

• Subsequent designs, having leveraged the simulated thermal model, performed even better than the initial prototype. This spurred development of surrounding hardware and software necessary to ensure the cooling method would perform during the course of a procedure.

• Included in this iterative process was the selection of the best materials to use. Weighing the pros and cons between conductive and insulative qualities, corrosion resistance, weldability and biocompatibility (to name a few) was a great experience for me. Since the camera is a medical device, it is imperative that all materials are safe for the patient, not to mention compatibility with our chosen sterilization method.

• The team gathered to evaluate risks and improve the system to a point where it was extremely robust and able to keep the camera within acceptable surface temperature limits nearly independently of the amount of heat being generated by the electronics.

• I was able to generate further test methods that recorded data from numerous thermocouples on cameras placed within a thermal chamber meant to simulate the conditions that the camera would experience during a procedure. Testing was carried out on a number of samples to prove the dependability of the design.

Current Project State

• The camera system has been tested in a variety of conditions, at all possible joint configurations and at all possible power levels. At this point, the design is effectively finalized

• More work may be done to streamline the initialization of the cooling system from the users' perspective. This comes as a result of the formative study mentioned in the Camera Manual Extraction project outline. Surgical technicians gave their feedback on the user input portion of the cooling system which we leverage towards improving the design.

Conclusion

• Solving the camera's thermal issue is probably the most thorough work I have done as both a professional and academic engineer. Myself and my team were able to start from nothing and develop this novel approach to a challenging task.

• The type of work involved here is some of my favorite. Starting with brainstorming sessions with my team, delegating tasks and gathering back up with our concepts is always an exciting part of a project.

• Iterating through designs using theoretical models and bringing those concepts to reality taught me about the importance of upfront thoroughness being a worthwhile investment of time when it comes to the final result.

• I'm very proud of the result that myself and my team was able to come to. We created and implemented a complex cooling system with what felt like hundreds of constraints on size, materials,