$\newcommand{\deriv}[2][]{\dfrac{\partial #1}{\partial #2}} \newcommand{\tderiv}[2][]{\tfrac{\partial #1}{\partial #2}} \newcommand{\fderiv}[2][]{\dfrac{d #1}{d #2}} \newcommand{\derivII}[3][]{\dfrac{\partial^2 #1}{\partial #2 \partial #3}} \newcommand{\tderivII}[3][]{\tfrac{\partial^2 #1}{\partial #2 \partial #3}} \newcommand{\derivIII}[4][]{\dfrac{\partial^3 #1}{\partial #2 \partial #3 \partial #4}} \newcommand{\tderivIII}[4][]{\tfrac{\partial^3 #1}{\partial #2 \partial #3 \partial #4}} \newcommand{\derivIV}[5][]{\dfrac{\partial^4 #1}{\partial #2 \partial #3 \partial #4 \partial #5}} \newcommand{\half}{\tfrac{1}{2}} % Macro for 1/2 \newcommand{\ud}{\mathrm{d}} \newcommand{\op}{\circ} \newcommand{\dq}{\dot{q}} \newcommand{\ddq}{\ddot{q}} \newcommand{\dt}{\Delta t}$

Damping – Damping on Configuration Variables

Damping implements a damping Force on the generalized coordinates of a system:

\[F_{q_i} = -c_i\ \dq_i\]

where the damping constant \(c_i\) is a positive real number.

One instance of Damping defines damping parameters for every configuration variable in the system. You can specify values for specific configuration variables and have a default value for the other variables.

Implemented Calculations

Calculation	Implemented
f	Y
f_dq	Y
f_ddq	Y
f_du	Y
f_dqdq	Y
f_ddqdq	Y
f_ddqddq	Y
f_dudq	Y
f_duddq	Y
f_dudu	Y

Examples

damped-pendulum.py, extensor-tendon-model.py, forced-pendulum-inverse-dynamics.py, initial-conditions.py, pccd.py, pend-on-cart-optimization.py, puppet-basic.py, puppet-continuous-moving.py, puppet-moving.py, pyconfig-spring.py, pypccd.py, radial.py

class trep.forces.Damping(system, default=0.0, coefficients={}, name=None)

Create a new damping force for the system. default is the default damping coefficient.

Damping coefficients for specific configuration variables can be specified with coefficients. This should be a dictionary mapping configuration variables (or their names or index) to the damping coefficient:

trep.forces.Damping(system, 0.1, {'theta' : 1.0})

Damping.default

The default damping coefficient for configuration variable.

Damping.get_damping_coefficient(config)

Return the damping coefficient for the specified configuration variable. If the configuration variable does not have a set value, the default value is returned.

Damping.set_damping_coefficient(config, coeff)

Set the damping coefficient for a specific configuration variable. If coeff is None, the specific coefficient for that variable will be deleted and the default value will be used.