Wire Goniometer
(A circuit to measure the angle of a wire moving on top of the CCD sensors)
This is an innovative solution I came up with for a problem that had perplexed me for a long time! To get the best performance of the winding machines and wind as many layers of wires as possible neatly on top of each other, the wire being wound on the bobbin needs to be as perpendicular as possible to the bobbin. So, there was a need to design a feedback circuit to measure the relative wire angle so that the machine can adjust the CNC X-axis and the speed of the motors accordingly. One possible solution was using a camera on top of the machine, a separate computer to measure the wire’s angle through image processing techniques. Not only would it make the system very complicated, the final cost could be so expensive.
I designed this circuit using two CCD linear sensors, a microcontroller and a few Op Amps. It can be installed somewhere between the bobbin and the winding nozzle to measure the wire angle. Four stages of Op Amp pre-amplifier along with ideal rectifier prepare analogue signal to be digitized by ADC. A Kalman filter helps the final data to be stabilized. The video below shows the performance of the circuit while a wire moving on top of the CCD sensors. The measured angle is sent through UART to the main controller in the CNC machine. Here the angle is visualized via gauges.
