Design of a compression depth and frequency tester for cardiopulmonary resuscitation machines based on a pneumatic test bench

To address the inefficiency and poor consistency caused by the separate measurement of compression depth and frequency using different equipment as stipulated in the current “JJF 1748—2019 Calibration Specification for Cardiopulmonary Resuscitation Machines”, this paper innovatively designs a pneumatic depth test bench. This bench utilizes the compressibility of confined gas to simulate the mechanical response of the human thoracic cavity and incorporates a guide shaft mechanism to significantly reduce the lateral swing error inherent in traditional spring-based structures. Centered around this test bench, this paper further develops an on-site calibration tester capable of simultaneous and high-precision measurement of compression depth and frequency by integrating a high-precision laser displacement sensor, a pressure control system, and an ARM processor. Experimental verification demonstrates that the technical indicators of the tester surpass the requirements of the specification, exhibiting excellent safety, universality, and reliability, thereby providing an effective technical solution for the rapid and accurate calibration of CPR machines.