movement_primitives.dmp.canonical_system_alpha

movement_primitives.dmp.canonical_system_alpha(goal_z, goal_t, start_t)

Compute parameter alpha of canonical system.

The parameter alpha is computed such that a specific phase value goal_z is reached at goal_t. The canonical system is defined according to [1], even though we compute a different value for alpha.

Parameters:

goal_zfloat

Value of phase variable at the end of the execution (> 0).

goal_tfloat

Time at which the execution should be done. Make sure that goal_t > start_t.

start_tfloat

Time at which the execution should start.

Returns:

alphafloat

Value of the alpha parameter of the canonical system.

Raises:

ValueError

If input values are invalid.

References

[1]

Ijspeert, A. J., Nakanishi, J., Hoffmann, H., Pastor, P., Schaal, S. (2013). Dynamical Movement Primitives: Learning Attractor Models for Motor Behaviors. Neural Computation 25 (2), 328-373. DOI: 10.1162/NECO_a_00393, https://homes.cs.washington.edu/~todorov/courses/amath579/reading/DynamicPrimitives.pdf