How to train the duck in MuJoCo to walk forward?

I changed gait_motions. I kept only "forward".
I opened part 4 in auto_waddle. Part 4 makes motions for slow, medium, and fast speeds.
Because i saw gait_motions is only used in part 4.

Then I ran --sweep to make a JSON file.
But when I used this file in runner.py, it crashed.

The error is:
```text
Open_Duck_Playground/playground/common/poly_reference_motion.py", line 148, in process
self.data_array[x][y][th] = jp.array(_data[dx][dy][dtheta])
~~~~~~~~~^^^^
KeyError: -3.407
```

I just want to konw how to train the duck to walk forward? Thanks.