LIDAR
- Model: Picollo Laser Distance Sensor, External Link
- Interface: UART, 8N1, 115200, RX=brown/TX=orange/+5V=red/GND=black
- Motor: 3.0V@25°C, 6-9V@-20°C - -30°C
- Warning: Motor requires a control loop as data is only delivered when RPM > 180
- Mechanical info here
- Aperture here
Freezer test
Overall result: Scan is stable at all temperatures tested. Motor requires control loop as its consumption varies with temperature. LIDAR was not spinning after 12hours in the freezer. This is because the rubber O-ring had frozen. The reason might have been that because the temperature dropped further, the motor slowed down, letting the almost motionless O-ring to freeze. Video of problem here.
| Time | °C | V | mA | RPM | Comment |
|---|---|---|---|---|---|
| 19:30 | 25 | 3.0 | 100 | 190 | Data OK |
| 19:42 | ? | 3.0 | 170 | No Data | |
| 19:42 | ? | 3.4 | 200 | Changed voltage, Data is back | |
| 19:46 | ? | 3.4 | No Data | ||
| 19:46 | ? | 3.7 | 200 | Changed voltage, Data is back | |
| 19:55 | ? | 3.7 | No Data | ||
| 19:55 | ? | 4.1 | 205 | Changed voltage, Data is back | |
| 19:57 | ? | 4.1 | No Data | ||
| 19:57 | ? | 5 | 180 | 240 | Changed voltage, Data is back |
| 20:10 | -13°C | 5 | No Data | ||
| 20:10 | -13°C | 5 | 240 | 239 | Changed voltage, Data is back |
| next day, 10:00 | -29°C | 5 | No Data, not spinning |
Motor controler via PID closed loop
- With 3V the motor turns at 190 rpms.
- PID controller has been implemented and can be found on the github (ROS/pid)
- pid node subscribes to /rpms topic and publishes into /control_effort topic ⇒ This is working
- The rpms need then to be “converted” into tension (V) that will be sent to the motor driver as PWM value.
- The node rpms2volts subscribes to /control_effort and publishes into /motor_input ⇒ Nothing is published… yet