Patent ID: 7905791

Claim:
A swing amplitude control device for controlling an amplitude of a swing, said swing being driven by a motor, said swing amplitude control device comprising: a swing amplitude sensor configured for outputting an electrical signal representative of an amplitude of said swing; and a swing amplitude control circuit configured for: receiving said electrical signal from said swing amplitude sensor; comparing said electrical signal with a goal amplitude signal; in response to said amplitude represented by said electrical signal from said swing amplitude sensor being greater than a goal amplitude represented by said goal amplitude signal, outputting a decrease signal to said motor to decrease said amplitude of said swing not more frequently than once every one and a half swing cycles; and in response to said amplitude represented by said electrical signal from said swing amplitude sensor being less than a goal amplitude represented by said goal amplitude signal, outputting an increase signal to said motor to increase said amplitude of said swing not more frequently than once every one and a half swing cycles.