Motion damping apparatus

Apparatus for controlling the movement of a movable element to bring said movable element to rest at a desired stopping position, said apparatus comprising:

• a multi-phase drive motor having a drive shaft coupled to said movable element for driving same, a plurality of electrically conductive coils mounted in position displaced relationship about said shaft, and means coupled to said drive shaft and responsive to the selective energization of said coils by respective motor drive signals for causing the corresponding rotation of said drive shaft and movement of said movable element;
• a sensor coupled to said drive shaft and responsive to the rotation thereof for generating an electrical signal containing information indicative of the direction, speed and distance of movement of said movable element;
• means for detecting from the distance information indicated by said electrical signal whether said movable element is within a predetermined distance of said desired stopping position;
• and
• control means for controlling the levels of said motor drive signals in dependence upon the direction information indicated by said electrical signal following detection of said movable element being within said predetermined distance of said desired stopping position, said motor and thus said movable element being brought to a final stop with only a single one of said motor drive signals and thus corresponding motor coil on, and wherein said single one of said motor drive signals and thus corresponding motor coil is turned on by said control means following detection of said movable element being within said predetermined distance and the two motor coils each adjacent said single one motor coil are selectively alternatively energized or deenergized by said control means, during movement of said movable element toward said desired stopping position, said two motor coils being energized only in the event that said sensor senses that the speed of said movable element is above a predetermined threshold speed.