rotations (version 1.6.5)

drill: Drill data set

Description

The drill data set was collected to assess variation in human movement while performing a task (Rancourt, 1995). Eight subjects drilled into a metal plate while being monitored by infared cameras. Quaternions are used to represent the orientation of each subjects' wrist, elbow and shoulder in one of six positions. For some subjects several replicates are available. See Rancourt et al. (2000) for one approach to analyzing these data.

Usage

drill

Format

A data frame with 720 observations on the following 8 variables:

Subject

Subject number (1-8)

Joint

Joint name (Wrist, elbow, shoulder)

Position

Drilling position (1-6)

Replicate

Replicate number (1-5)

Q1

First element of orientation (quaternion)

Q2

Second element of orientation (quaternion)

Q3

Third element of orientation (quaternion)

Q4

Fourth element of orientation (quaternion)

References

1. Rancourt, D. (1995). "Arm posture and hand mechanical impedance in the control of a hand-held power drill." Ph.D. Thesis, MIT.

2. Rancourt, D., Rivest, L. & Asselin, J. (2000). "Using orientation statistics to investigate variations in human kinematics." Journal of the Royal Statistical Society: Series C (Applied Statistics), 49(1), pp. 81-94.

Examples

# Estimate central orientation of the first subject's wrist
Subject1Wrist <- subset(drill, Subject == 1 & Joint == "Wrist")
Qs <- as.Q4(Subject1Wrist[, 5:8])
mean(Qs)

# \donttest{
  # Plot Subject 1's wrist measurements using the connection to rotation matrices
  plot(Qs, col = c(1, 2, 3))
# }

# Translate the quaternion measurements into rotations and
# estimate the central orientation in terms of rotations
Rs <- as.SO3(Qs)
mean(Rs)