Couch Top Pitch and Roll Motion by Linear Wedge Kinematic and Universal Pivot

2:

• The assembly of claim 1, wherein each of the first and the second actuators comprises:
• a wedge assembly, comprising:
• a first carriage on the first structural element, the first carriage being translatable along a first horizontal direction, the first carriage comprising an inclined plane;
• a second carriage on the inclined plane, the second carriage being translatable along the first horizontal direction;
• a third carriage translatable against a bottom side of the second structural element, the third carriage being translatable along a second horizontal direction perpendicular to the first horizontal direction, the third carriage comprising a spherical bushing;
• and
• a fastener securing the third carriage through the spherical bushing to the second carriage.

4:

• The assembly of claim 2, wherein:
• the first carriage comprises one or more first linear bearings that engage one or more first rails mounted along the first horizontal direction on the first structural element;
• the second carriage comprises one or more second linear bearings that engage one or more second rails mounted along the first horizontal direction on the inclined plane;
• and
• the third carriage comprises one or more third linear bearings that engage one or more third rails mounted along the second horizontal direction on the bottom side of the second structural element.

5:

• The assembly of claim 2, wherein each of the first and the second actuators comprises:
• a screw drive, comprising:
• a spindle shaft;
• and
• a wedge link comprising or being attached to a nut on the spindle shaft, the wedge link being coupled to the first carriage;
• and
• a motor coupled to the spindle shaft.

8:

• The assembly of claim 2, further comprising:
• first and second rotary feedback devices on ends of the first shaft;
• and
• third and fourth rotary feedback devices on ends of the second shaft.

11:

• The assembly of claim 1, wherein the universal joint further comprises:
• an upper mount comprising first bearing housings;
• first bearings being mounted to the ends of the second shaft, the first bearings seated in the first bearing housings;
• a lower mount comprising second bearing housings;
• and
• second bearings mounted to the ends of the first shaft, the second bearings seated in the second bearing housings.

12:

• The assembly of claim 11, wherein the universal joint further comprises:
• first adjustable hard stops extending from the upper mount toward the second shaft to limit rotation of the first shaft;
• and
• second adjustable hard stops extending from the lower mount toward the first shaft to limit rotation of the second shaft.

13:

• The assembly of claim 5, further comprising:
• a first rotary feedback device on one end of the first shaft;
• a second rotary feedback device on one end of the second shaft;
• and
• third and fourth rotary feedback devices coupled to the motors of the first and the second actuators.

15:

• The assembly of claim 13, further comprising:
• a communication interface;
• a power amplifier coupled to the motors;
• an input/output (I/O) interface coupled to the first, the second, the third, and the fourth rotary feedback devices;
• and
• a controller coupled to the communication interface, the power amplifier, and the I/O interface.

16:

• The assembly of claim 15, wherein the controller is configured to:
• receive, via the communication interface, a reference pitch about the first horizontal axis and a reference roll about the second horizontal axis;
• receive, via the I/O interface, an actual pitch and an actual roll from the first and the second rotary feedback devices on the universal joint;
• determine reference positions for the motors based on a difference between the reference and the actual pitches and a difference between the reference and the actual rolls;
• receive, via the I/O interface, measured positions of the motors from the third and the fourth rotary feedback devices;
• determine motor commands for the motors based on the differences between the reference and the measured positions of the motors;
• and
• instruct the power amplifier with the motor commands for the motors.

18:

• The assembly of claim 15, wherein the controller is configured to:
• receive, via the communication interface, motor commands from an other controller;
• provide the motor commands to the power amplifier;
• receive, via the I/O interface, a measured pitch and a measured roll from the first and the second rotary feedback devices on the universal joint;
• receive, via the I/O interface, measured positions of the motors from the rotary feedback devices in the first and the second actuators;
• and
• send, via the communication interface, the measured pitch, the measured roll, and the measured positions of the motors to the other controller.

19:

• The assembly of claim 1, wherein each of the first and the second actuators comprises:
• a first link being translatable along a first horizontal direction on the first structural element;
• and
• a second link having a first end coupled to the first link and a second end coupled to the second structural element.

21:

• A couch top for positioning a patient, comprising:
• a base, comprising;
• a top side;
• and
• on the one or more first rails mounted on the top side parallel to a Y axis;
• a top, comprising:
• a bottom side;
• and
• one or more second rails mounted to the bottom side parallel to an X axis
• a universal joint coupled between the top and the base so the top is rotatable about the X and the Y axes, the universal joint comprising a cross shaft with a pitch shaft and a roll shaft;
• a first primary encoder on one end of the pitch shaft;
• a first secondary encoder on another end of the pitch shaft;
• a second primary encoder on one end of the roll shaft;
• a second secondary encoder on another end of the roll shaft;
• first and second actuators mounted on the base, the first and the second actuators being coupled to the top on different sides of the Y axis, each of the first and the second actuator comprising:
• a motor;
• a resolver on the motor;
• a screw drive, comprising:
• a spindle shaft coupled to the motor;
• and
• a wedge link comprising or being attached to a nut on the spindle shaft;
• a wedge assembly, comprising:
• a first carriage coupled to the wedge link, the first carriage comprising one or more first linear bearings riding on the one or more first rails on the base, the first carriage comprising one or more inclined rails parallel to the Y axis;
• a second carriage comprising one or more second linear bearings riding on the one or more inclined rails;
• a third carriage comprising one or more third linear bearings engaging the one or more second rails on the bottom side of the top, the third carriage comprising a spherical bushing;
• and
• a fastener securing the third carriage through the spherical bushing to the second carriage;
• a communication interface;
• a power amplifier coupled to motors of the first and the second actuators;
• an input/output (I/O) interface coupled to the first, the second, the third, and the fourth encoders and the resolvers;
• and
• a controller coupled to the communication interface, the power amplifier, and the I/O interface.