Multi-Axis Micro Force Sensor Based on a CMOS Integrated Chip

Abstract:
This paper presents the design, fabrication, characterization, and successful demonstration of a multi-axis micro-force sensor system. The core of the design are a CMOS integrated transducer and a specially designed load cell for multi-axial force application. The special features of this solution are a small-size axially symmetric load cell, which concentrates multi-axial loads onto one measuring point, where they are captured by CMOS sensor elements on a single stress sensor chip. As the electrical signal conversion is carried out on the side of the load cell facing away from the force application, the design ensures a separation of media. The telemetry interface for energy and data transmission allows good interchangeability and complete encapsulation of the sensor. For demonstration purposes, a quasi-displacement-free joystick system, with a nominal measuring range of 0.5 N was set up, as required e.g. by persons with handicaps like ataxia or paraplegia. In addition, this compact and robust force-sensor solution opens up a wide range of other applications: From force-sensitive robotics and precision machining to human-machine interfaces and vortex-acting pressure flow sensors.