Fast Force Control without Force Sensor Using Combination of aaKF and RFOB for In-circuit Test with Probing System

The in-circuit test is performed by pushing a needle-type probe into the printed circuit board (PCB) and measuring the conductivity between the electronic components. To reduce the testing time and improve the test reliability, a swift and stable motion of the probe is required, especially when the probe touches the surface of the PCB. Instead of the conventional method involving the use of a force sensor, this study investigates the application of a micro electronical mechanical systems accelerometer to realize the quick contacting motion. The detection of the contact instant is evaluated by the jerk signal from this device. Subsequently, a negative force is added to the probe and the proposed force control based on acceleration aided Kalman filter and reaction force observer is applied. The experimental verification indicates that the settling time is reduced to approximately 10 ms and this corresponds to nearly 1% of the comparison data based on the existing technique.