repair a robot vacuum cleaner

Submitted by Pelgrim on Wed, 11/18/2020 - 15:33

hi,

I'm trying to repair a robot vacuum cleaner, brand clatronic.

Symptoms: it only operates in reverse, while it should go forward and turn in the event the front sensors are activated.

The front bumper is pushing 3 sensors inward, which in normal operation activate a reverse motion and some turn before moving forward again.

Light sensors ?

 

After disassmbling and testing, I concluded that the sensors don't do anything anymore, if connected or disconnected, the motors keep spinning in reverse.

The sensor looks like this:

The outer cables have a voltage of 2.5 V, permanently powering the dark component (lower left on the picture).

The upper left component is connected with the 2 first cables, which I would suspect is the sensor making a connection.

 

The sensor cable:

3 of these are connected to this board:

So the quetion is simple: can this be repaired ?

Its hard to troubleshoot without any testing. Are you sure that the failure is because of the sensor? 

If your robot can be controlled directly with a remote (most vacuum bots have this option) try controlling it directly, this will override the sensors and you should notice the wheel move in forward. If that happens we can almost be certain that the problem is with the sensors 

  Joined August 16, 2016      998
Tuesday at 12:29 AM

thank you for your reply.

Unfortunally it's not that modern, it has an on/off switch, nothing else.

 

When switched on, it moves like less then 1 cm forward, and then switches backwards.

One more thing to note: the only way to get it working now is to unplug the main power while the switch is on, that starts it. When switched on without main power, it doesn't react.

For some strange reason it the battery power is only drawn in this way.

 

  Joined November 18, 2020      3
Wednesday at 02:57 PM

Hi, I wasn't too sure if the 3 sensors you mention are all at the front of the machine as I'd expect others on the sides and back. The PCB sockets for sensors and the 2x motors all look the same, have you tried swapping the plugs around and seeing if there's any different reaction? I also suspect there might be 'loading' detection - i.e. if a motor controller encounters a sudden difference in current it might think the device has hit an obstacle and then might throw itself into reverse, so try the unit off the ground.

My thoughts are, unfortunately, that the sensors are likely to be bulletproof and the underlying fault is probably the logic components. 

  Joined November 19, 2020      1
Thursday at 03:56 AM

might be so.

I tested with sensors disconnected, partially connected, all seems to be ignored by the logic.

Anyway, here is how it looks like, it's not assembled, but this is how the front bumper looks like.

The sensors are not on the sides, but a bit "sideways".

  Joined November 18, 2020      3
Wednesday at 02:57 PM

It is something that the sensor is malfunctioning. My best guess is by any chances the IR sensor is turned on continuously, and it is drawing current from the battery also.

Do you check if there is some options to reset everything, or atleast any configuration or setting that has been made.

Do you have the model number?

  Joined February 12, 2018      696
Monday at 02:11 PM