Abstract: A disk drive is disclosed comprising a disk, and a head actuated radially over the disk. A first linear acceleration signal is generated representing a first acceleration disturbance, a second linear acceleration signal is generated representing a second acceleration disturbance, and a third linear acceleration signal is generated representing a thermal popping disturbance. The first linear acceleration signal is combined with the third linear acceleration signal to generate a fourth linear acceleration signal representing a combined physical shock disturbance and thermal popping disturbance.

Abstract: A disk drive is disclosed comprising a spindle motor comprising a plurality of windings for rotating a disk. The spindle motor is rotated by commutating the windings over a plurality of commutation states, wherein audible noise generated by the disk drive is reduced by phase modulating the commutation interval. Further audible noise reduction is achieved by modulating a current applied to the windings which substantially reduces discontinuities in the torque output of the spindle motor caused by phase modulation of the commutation intervals.

Abstract: Methods and devices for converting the kinetic energy of the rotating spindle motor of a disk drive of a rechargeable battery operated mobile host device into electrical energy during braking of the rotating spindle motor. The converted electrical energy is conditioned and used to charge the rechargeable battery of the mobile host device.

Abstract: A disk drive comprising a programmable inverting voltage regulator (PIVR) for generating an inverted voltage supply applied to a preamp is disclosed. The PIVR is programmably configured relative to the disk drive's mode of operation, including a read mode and a write mode.

Abstract: A disk drive incidentally generates undesirable acoustic noise during an operation mode and includes a spindle motor having windings and a rotor rotatable at an operating spin-rate during the operation mode. A commutation state sequencer includes a sequence of commutation states including a present commutation state and a next commutation state for generating a sequence of control signals. Switching elements are responsive to the sequence of control signals for sequentially applying a voltage across a selected combination of the windings to generate a torque on the rotor in order to maintain the operating spin-rate. A spindle motor control system provides a series of commutation clock pulses having a corresponding series of commutation clock periods to advance the commutation state sequencer from the present commutation state to the next commutation state.

Abstract: A rapid prototyping and manufacturing (e.g. stereolithography) apparatus includes a secondary frame located within a primary frame of the system. The secondary frame defines an enclosure for housing a number of peripheral heat-producing components and peripheral vibration-producing components. The heat generated by these peripheral heat-producing components is substantially isolated in the enclosure and is removed from the primary frame so as not to cause an undesired impact on other components within the main frame. The secondary frame preferably sits directly on the floor or other surface without touching the primary frame, thus substantially avoiding transmittance of vibration from components in the enclosure to the primary frame of the system.

Abstract: An arc welder control in which the current is pulsed between a high level and a low level. The high level pulse is maintained until a selected energy condition is satisfied. The low level pulse is maintained to satisfy an average energy condition. A proximity control moves the torch head and the feed wire tip toward and away from the work to stabilize a parameter of welder operation which may deviate with the current pulse energy control.

Abstract: A motor control system for a high accuracy incremental motion system such as a paper feed system in a high speed printer. The system utilizes a stepping motor which is driven in one of two modes, depending upon its position. During most of the movement from one position to another, the motor is driven as a DC brushless motor. This is accomplished by commutating the phases of the motor so that they are energized around the peaks of their torque curves. The motor is driven in a closed loop fashion, with velocity commands being generated by a velocity profile generator incorporating a microprocessor. Both position and velocity feedback are utilized. Since the motor is driven as a DC brushless motor, traditional control theory methods (e.g., Root locus, Bode, etc.) can be employed.As the motor nears the final desired position, the system switches so that the motor is energized as a step motor.