Ground Contact#

Constraints for ground contact forces and kinematics.

class biosym.constraints.ground_contact.Constraint(model, settings, args)#

Bases: BaseConstraint

Base class for dynamics constraints in the biosym package.

This class provides a template for implementing specific dynamics constraints. It includes methods for evaluating the constraint function, computing the Jacobian, and retrieving information about the constraint.

get_confun()#

Evaluate the dynamics constraint function.

Parameters:

states_list – Dictionary containing the current states.

Returns:

The dynamics constraint function.

get_jacobian()#

Get the Jacobian of the dynamics constraint function.

Parameters:

states_list – Dictionary containing the current states.

Returns:

The Jacobian of the dynamics constraint function.

get_n_constraints()#

Get the number of constraints defined by this dynamics constraint.

Returns:

The number of constraints.

get_nnz()#

Get the number of non-zero entries in the Jacobian of the dynamics constraint.

Returns:

The number of non-zero entries.

biosym.constraints.ground_contact.confun(model, states_list, globals_dict, settings, info)#

Placeholder for the constraint function.

This function should be implemented in subclasses to evaluate the dynamics constraints.

Parameters:

  • states_list – List containing the current states.

  • settings – Dictionary containing settings for the dynamics constraint.

  • info – Information about the constraint function.

Returns:

The evaluated value of the constraint function.

Todo: there is some non-jax logic in here, which could be replaced with a static function

biosym.constraints.ground_contact.jacobian(model, states_list, globals_dict, settings, info)#

Placeholder for the Jacobian of the constraint function.

This function should be implemented in subclasses to compute the Jacobian of the dynamics constraints.

param states_list: List containing the current states. :param settings: Dictionary containing settings for the dynamics constraint. :param info: Information about the constraint function. :return: The Jacobian of the constraint function.