title: Interface

In order to create an environment, use:

from osim.env import ProstheticsEnv

env = ProstheticsEnv(visualize=True)

Parameters:

• visualize - turn the visualizer on and off

Methods of ProstheticsEnv

reset(project = True)

Restart the enivironment.

The function returns:

• observation - a vector (if project = True) or a dictionary describing the state of muscles, joints, and bodies in the biomechanical system.

step(action, project = True)

Make one iteration of the simulation.

• action - a list of continuous values in [0,1] corresponding to excitation of muscles. The length of the vector is expected to be: 22 and 18 for 3D and 2D models without the prosthesis; 19 and 15 with a prosthesis.

The function returns:

• observation - a vector (if project = True) or a dictionary describing the state of muscles, joints, and bodies in the biomechanical system.

• reward - reward gained in the last iteration.

• done - indicates if the move was the last step of the environment. This happens if either 300 iterations were reached or the pelvis height is below 0.6 meters.

• info - for compatibility with OpenAI, currently not used.

change_model(model='3D', prosthetic=True, difficulty=0,seed=None)

Change model parameters. Your solution will be graded in the environment with difficulty = 2, prosthetic = True and model = 3D, yet it might be easier to train a simplified model first (where model = 2D, difficulty = 0, prosthetic = False` is the simplest).

• model - 3D model can move in all directions, 2D one dimension is fixed, i.e. the model cannot fall to the left or right.

• prosthetic - if True the right leg of the model is a prosthesis.

• difficulty - For the 3D model: 0 - go forward at 3 meters per second, (other values not used for now)

• seed - starting seed for the random number generator. If the seed is None, generation from the previous seed is continued.

This function does not return any value. reset() must be run after changing the model.