Centrifuge with tilt control

A centrifuge (AP1) includes a centrifuge rotor (13) that rotates to provide supergravity conditions and tilt rotors (17) that provide for sample agitation under the supergravity conditions. The centrifuge rotor is integral with a hollow centrifuge drive shaft (49). A tilt-drive shaft (69) extends through the hollow and rotates coaxially of the centrifuge rotor. The tilt-drive shaft has a pinion (71) that engages the tilt rotors, which thus are made to rotate about tilt axes that are spaced from and parallel to the centrifuge axis. A centrifuge motor (41) is mechanically coupled to the centrifuge drive shaft to rotate the centrifuge rotor. A tilt motor (61) is mechanically coupled to the tilt drive shaft for imparting a rocking motion of the tilt rotors (and thus of mounted sample containers (100)) relative to the centrifuge rotor. Both motors are controlled by a servo (23) that receives orientation information from orientation encoders (75 and 77) associated with the motors; the tilt motor is phase locked to the centrifuge motor to ensure precise relative motion control. The centrifuge motor is typically rotated to achieve a centrifugal force at the tilt rotors of about 1000 G. The tilt motor is controlled differentially relative to the centrifuge motor so that the tilt rotors rotate controllably, at, above and/or below the centrifuge rotation rate to achieve the desired rotation relative to the centrifuge.