Question Zhuo teacher Hello, I would like to ask you a question, I am a camera group, recently our car out a little
Metaphysical issue that must pinch with hands cable camera data to pass back.
Replacement camera, replace the cable, there is no way, I asked a lot of seniors and met the teacher said no, saying it was a hardware problem. Indeed, another group also appeared this problem, so they re-weld a piece of board just fine, but I want to figure out the problem in the end went wrong?
VCC and GND are normal, but only to the camera VCC power supply is connected directly to GND. Respective signal lines are turned on, Weld phenomenon. Moreover, the image for some time before the camera is capable of real-time transmission, suddenly gg two days, the teacher Point to give us directions to check the circuit thing?
Reply metaphysical problem you encountered may be related to integrity (Signal Integrity, or SI) signal.
You use camera is a digital camera estimates, the CCD read data to the microcontroller via the parallel lines. In fact any signal are analog signals, digital signals just be abstract and simplified. For the distribution parameter will be high-speed signals over the signal circuit mess.
Integrity (Sigrity) signal is stable high-speed digital circuit design factors to be considered, if not handled properly, there will be metaphysical problem you have described. Sigrity design includes the following aspects:
Determines the signal integrity at the receiving end the signal of which waveform, amplitude distortion and noise. If it is not for the receiving end to the amplitudes, time, etc. of the desired signal, there will be a communication;
Hand holds the camera cable, the transmission line distributed capacitance will change, thereby affecting the transmission line impedance, which changes in the integrity of the signal transmission process. I suggest that you read the two ends of the camera increased impedance matching resistors, capacitors; or a suitable frequency can be reduced to improve the situation. Oscilloscope by correct measurement, observe the waveform of the signal transmission integrity.
Question Zhuo teacher, hello, Excuse me, I would like to ask your questions about the incremental pid. Incremental pid pid is a variant type of position, with the motor I was pi, in accordance with the definition of p pid play a leading role, i play a role in the elimination of poor stability, but I tune when i set to 0, regardless of p to much, they are lower than the velocity of the target. After i gave in order to achieve, then if some oscillation wave reaches the target value, adjusting a small p can reduce the oscillation.
Theory this phenomenon and it does not match the pid, I do not know whether I was wrong or formula columns incremental motor problems. My formula is this column:
Change + = KP * (s-last_er) + ki * is;
er = set_speed (target speed) -now_speed (encoders, the value of the motor)
change is the final output of the pwm,
last_er for the last time bias.
This problem has troubled me for a long time, hope can answer greatly Zhuo clear my doubts.
Reply
