add set environment variable

[GithubMingEnter]

run python file

$ python models/kinematic_car_test.py 
Traceback (most recent call last):
  File "models/kinematic_car_test.py", line 9, in <module>
    from control.dcbf_optimizer import NmpcDcbfOptimizerParam
ModuleNotFoundError: No module named 'control'