Devices and systems for correcting errors in blood pressure measurements

A wrist-worn device comprising:

• a pressure sensor for measuring a pressure signal from a target artery;
• an actuator coupled with the pressure sensor, wherein the actuator is configured to apply an applanation force to a wrist of a user during pressure measurement by the pressure sensor, and wherein the actuator comprises an actuator sensor for monitoring a displacement distance of a contact end of the actuator as it moves against the wrist of the user over a reconfiguration of the actuator, between a first configuration and a second configuration, that induces a variation in the applanation force applied to the wrist via the contact end of the actuator;
• and a processor coupled with the pressure sensor and the actuator, wherein the processor is configured to:
• monitor the pressure signal and the actuator sensor during an actuation of the actuator to identify an amount of the displacement distance of the contact end of the actuator as it moves against the wrist of the user that reconfigures the actuator from the first configuration to the second configuration or from the second configuration to the first configuration, wherein the second configuration of the actuator results in a desired variation in the pressure signal, and wherein the applanation force in the second configuration is greater than the applanation force in the first configuration;
• determine a correction factor based on the identified amount of the displacement distance of the contact end of the actuator as it moves against the wrist of the user;
• and calculate a blood pressure value based on the pressure signal from the pressure sensor and the correction factor.