Hi
I purchased a 4WD Hercules Mobile Robotic Platform from you folks late last year.
I love the mechanical quality of the Kit, but have had a heck of a time with the seed software and driver support.
I am at a point now that I need to use the encoders on the motors to provide feedback to my control system. I cannot find any specifications on the “built in” encoders included with the kit or specifications the motors that were provided.
Can you provide this information? Basically I need to know what “the encoders are”, to get some data sheets so I can work out how to read them and then make use of the data.
Also, what are the “kit included” motors so I can get replacements if required. If these “stock” motors are insufficient for the task, I would like to know how to get something that will report current rpm and ideally direction in a form the control board can use. ( I am aware that the stock motors cannot report direction.)
I am also open to suggestions for an alternative means to read the speed (rpm) of each “side”
As for the encoders, we have contacted the manufacturer to ask them for datasheets, specifications or product code.
We will update the 4WD Hercules page and post their reply here as soon as we get it.
I have that specification for the motor. If you google the model there are no matches, so it does not help in getting replacements.
By manually turning the motor the gear ratio was found to be 36:1 this implies that the encoder would report 72 pulses per revolution if I am reading it correctly.
Next is how to correctly connect the encoder and then read the internal PIN’s on the motor controller. Once this is determined, there are some Arduino libraries that can be adapted to work.
If you are planning to replace the motors and by knowing the motors specifications, you may consider choosing similar motors with encoders, using this comparison table.
As for the encoders, please find in the attached picture the connectors for the encoders on the controller.
You can find inthis link some sample codes to read quadrature encoders.
If I read the response correctly, there is no direct replacement for these motors. Does this mean if one fails I will have to replace all 4 of them? Am I understanding your response correctly? I ask because one is becoming increasingly noisy with less than 2 hours run time at no load. The bot is on a platform whilst I am still just testing the firmware.
I previously followed the same path as your suggestion, in my attempts to get the encoders working. These motors do not seem to have “quadrature encoders”, which is why I asked the question earlier on this forum about what type they were. I need that information so I can figure our the correct library / or, gods forbid, write one.
We unfortunately don’t offer a direct replacement for the motors of the 4WD Hercules Mobile Robotic Platform.
We have contacted Seeedstudio to obtain the specifications of the encoders. We didn’t yet receive a reply.
You are correct, it appears that the encoders of the 4WD Hercules Mobile Robotic are revolution-counters (Tachometers) that measure the rotation speed only (vs quadrature encoders that provide direction).
Did you try the library of the motor controller?
Thanks, yes I tried that library and some others from Seeed, I could not get them to work. Neither could others on the Seeed forums.
Since I would prefer to sense direction too, are you aware of any “retro-fit” parts that I can purchase to upgrade these motors to quadrature encoders? I have no idea on how to specify them otherwise I would try and look them up.
Getting the encoders to work is now on my critical path so any pointers would be appreciated.
We apologize for the delay. We have received a reply from the manufacturer and they said that they don’t have a sample code for these encoders.
Please take a look at our Encoders section. We don’t provide a specific replacements/upgrade encoders for these motors.
