This is a list of possible sensors for inclusion
Gyro - ideally, this robot should be able to walk on a grade and maintain the upright orientation of the hub. Useful for side-grades and inclines, keeps camera or other equipment on the level.
Optical flow sensor - this would allow the robot to track actual movement (for measuring slippage and closely estimating location)
Pressure sensor - incorporated into the leg joint(s) to signal ground/other contact and with the appropriate sensor, measure amount of force applied to each 'foot'
Ultrasonic distance sensors - for obstacle avoidance and relative positioning
Camera(s) - also for obstacle avoidance and relative positioning, (obstacle recognition?)