This crane control apparatus and method with swing control and variable impedance
is intended for use with overhead cranes where a line suspended from a moveable
hoist suspends a load. It is responsive to operator force applied to the load and
uses a control strategy based on estimating the force applied by the operator to
the load and, subject to a variable desired load impedance, reacting in response
to this estimate. The human pushing force on the load is not measured directly,
but is estimated from measurement of the angle of deflection of the line suspending
the load and measurement of hoist position.