SpatialWrench – Apply a spatial wrench to a frame.

SpatialWrench applies a fixed or variable wrench to a coordinate frame. The wrench is expressed in the world coordinate frame and applied to the location of the world origin in the coordinate frame.

\[F_{q_i} = \left(\deriv[g]{q_i} g^{-1}\right)^{\displaystyle\check{}} \cdot f\]

where \(g_1\) is the coordinate frame the wrench is applied to and \(f\) is the wrench. The wench is a vector of six numbers that defined the forces applied to the x, y, and z axes and torques about the x, y, and z axes. In trep, each component of the wrench can be a fixed real number or an input variable (trep.Input).

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

SpatialWrench(system, frame, wrench=tuple(), name=None):

Create a new spatial wrench force to apply to frame.

wrench is a mixed tuple of 6 real numbers and strings. Components that are real numbers will be constant values for the wrench, while components that are strings will be controlled by input variables. An instance of Input will be created for each string, with the string defining the input’s name.

SpatialWrench.wrench

A mixed tuple of numbers and inputs that define the wrench.

(read-only)

SpatialWrench.wrench_val

A tuple of the current numeric values of the wrench.

SpatialWrench.frame

The frame that this wrench is applied to.

(read-only)