Patent ID: 8616088

Claim:
A control method for a joint device, comprising: providing the joint device, wherein the join device comprises: a rotary shaft; two fixing members, pivoted to each other through the rotary shaft; two driving members, respectively fixed to the fixing members; two transmission gears, respectively connected to the driving members respectively driving the transmission gears to rotate; and a link gear, pivoted to one of the fixing members, wherein a pivot axis of the link gear and the rotary shaft are coaxial, the link gear is engaged with the transmission gears respectively, and a relative position between the pivot axis and any one of the fixing members remains constant; wherein the transmission gears and the link gear are all bevel gears, and the transmission gears have the same pitch diameter and number of teeth; setting pivoting directions of the transmission gears relative to the rotary shaft to be the same, and setting a relative speed difference of the transmission gears to be greater than zero, so that a relative angular speed of the fixing members is greater than zero to rotate the joint device in a direction; and changing the relative speed difference of the transmission gears to be smaller than zero, so that the relative angular speed of the fixing members is smaller than zero to rotate the joint device in a reverse direction without changing the pivoting directions of the transmission gears.