Compute acceleration from position or velocity data

Computes acceleration (second derivative) from position or velocity assays. If velocity assays already exist, differentiates those (first derivative of velocity). Otherwise, computes the second derivative of position directly.

Usage

computeAcceleration(
  pe,
  assay_names = NULL,
  method = "central",
  sampling_rate = NULL
)

Arguments

pe

A PhysioExperiment object.

assay_names

Character vector of assay names to differentiate. If NULL (default), auto-detects velocity_x/y/z (preferred) or position_x/y/z assays.

method

Finite difference method: "central" (default), "forward", or "backward".

sampling_rate

Sampling rate in Hz. If NULL (default), uses samplingRate(pe).

Value

PhysioExperiment with new accel_x, accel_y, accel_z assays added.

References

Winter DA (2009). "Biomechanics and Motor Control of Human Movement." 4th ed. John Wiley & Sons.

See also

computeVelocity() for first-order derivatives, computeJerk() for third-order derivatives, differentiate() for general-purpose numerical differentiation.

Examples

if (FALSE) { # \dontrun{
pe <- make_mocap_markers(n_time = 100, n_markers = 4, sr = 120)
pe <- computeAcceleration(pe)
} # }