Consecutive movements in primitive

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1

Hi

I try to implement consecutive movements for two motors in a primitive like this:

class ShowPrimitive(pypot.primitive.Primitive):
    def run(self):
        self.robot.m2.goto_position(0., 1., control="dummy", wait=True)
        time.sleep(.2)
        self.robot.m1.goto_position(0., 1., control="dummy", wait=True)

On first start() both motors move as expected - consecutive. But on second start() for this primitive, both motors are moving at the same time. 3rd start is ok, 4th start not ok, and so on …
If I set control="minjerk" the motors move sometimes erratic.

What’s wrong?

My Setup:
XL320
Raspberry 2
Miniconda Python 2.7.10
PyPot 2.10.0

2

That’s strange. Can you show me the rest of the code? I’ll try to reproduce the problem.

3

Hi Pierre

Until now it’s just a kind of test program. I see this problem, when I invoke the ShowPrimitive (enter “g”) and the HidePrimitive (enter “h”) alternating. Other primitives are running fine.
If I switch on logging, I can see, that to both motors values are sent in the problem case.
Used config:

{
  "controllers": {
    "my_dxl_controller": {
      "sync_read": true,
      "protocol": 2,
      "attached_motors": [
        "m1", "m2"
      ],
      "port": "/dev/ttyACM0",
      "syncloop": "LightDxlController"
    }
  },
  "motorgroups": {
  },
  "motors": {
    "m1": {
      "offset": 0.0,
      "type": "XL-320",
      "id": 1,
      "angle_limit": [
        -90.0,
        90.0
      ],
      "orientation": "direct"
    },
    "m2": {
      "offset": 0.0,
      "type": "XL-320",
      "id": 2,
      "angle_limit": [
        -90.0,
        90.0
      ],
      "orientation": "indirect"
    }
  }
}

Thanks
Gerald

robot.py (5.2 KB)

4

Good catch actually! I’ve spent some times reproducing what you observed and trying to understand were the problem came from.

I think it was because we forget to clear some values from the previous run of a primitive before re-running it. I’ve pushed a branch with a fix here:

https://github.com/poppy-project/pypot/tree/fix-consecutive-primitives

It solves the problem on my test bench (using the simulator), can you tell me if it works for you?

Thanks for the bug report!

5

Hi Pierre

Thanks for your analysis and your bug fix. Now the primitives works as expected. :grinning:

Greetings from Switzerland
Gerald

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6

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