Patent ID: 6799649
Filing Date: 2004-10-05
Classification: A61G,B62K,G05B,Y10T

Abstract:
A method for enabling a payload to ascend and descend stairs, each stair having a riser, the method comprising:a. providing a device, the device comprising: i. a support for supporting the payload; ii. a ground contacting element movable with respect to a local axis, the local axis being movable with respect to a second axis having a defined relation with respect to the support; iii. a motorized drive arrangement for permitting controllable motion of the ground contacting element with respect to the local axis in such a manner that the local axis moves with respect to the second axis so as to operate in an operating condition that is unstable with respect to tipping in at least a fore-aft plane when the motorized drive arrangement is not powered; and b. maintaining wheel torque against each riser successively; and c. changing the relation of the local axis with respect to the support so as to maintain the center of gravity of the device and the payload between specified limits in forward and rearward directions of rotation of the device.