FIG. 6.
Stability and repeatability was established over a 3-week dynamic loading period, during which time, the stepper motors were cycled (1 Hz, 30 min on, 1 h off) to apply a target force of 1.2 N. Force-time traces show three representative 30-min cycling periods (only peak force recorded) in which, there was a maximum deviation from target force of±0.04 N.