Load Cell Force and Direction Sensor System for Push Bars

This paper presents the theory, design, and development of force sensor system using load cells that can provide force magnitude and direction from the handle of a mobile system. A novel mechatronic based patient transfer system is being created as an alternative to sling transfers. This new system is heavy, and staff will require power assistance to move and position the transfer system. Handles on the system provide the expected push bars that staff currently use on gurneys and the proposed sensor system allows the forces on handles to be measured as inputs to a power assist system. The results shown that the sensor provides a linear relationship for force magnitude and allows for the measurement of direction of force with minimal error without requiring detailed calibration of each of the sensors. The results are presented for forces in 8 different directions for a range of force magnitudes. Results show that force magnitude can be estimated with an average standard deviation of 10% and the direction can be measured with an approximately standard deviation of 1%.