Aspects of the invention provide methods and systems for moving a plurality of moveable stages relative to a stator. The stator comprises a plurality of coils shaped to provide pluralities of coil trace groups where each coil trace group comprises a corresponding plurality of generally linearly elongated coil traces which extend across a stator tile. Each moveable stage comprises a plurality of magnet arrays. Methods and apparatus are provided for moving the moveable stages relative to the stator, where a magnet array from a first moveable stage and a magnet array from a second moveable stage both overlap a shared group of coil traces. For at least a portion of the time that the magnet arrays from the first and second moveable stages overlap the shared group of coil traces, currents are controllably driven in the shared coil trace group based on the positions of both the first and second moveable stages. The positions of the first and second moveable stages may be ascertained by feedback.

A method for controlling the drive current in a stepper motor includes measuring stepper motor current, computing a load angle of the stepper motor, calculating a torque ratio of the stepper motor, generating a reference current as a function of the torque ratio and a maximum current setting for the stepper motor, and setting the drive current of the stepper motor as a function of the reference current.

An H-bridge pre-driver is configured as two blocks so as to suit the width of an H-bridge driver Tr. The two blocks are line-symmetrically placed with a bias circuit interposed therebetween. One of the pre-driver blocks is laid out as a rectangle that is long in one direction and is short in a direction perpendicular to that direction. With this configuration, the pre-driver layout area can be reduced, and the cost of IC can be reduced. Furthermore, the symmetric placement enables matching of the impedance of interconnect from the pre-driver to the driver and stabilization of properties to be achieved.

An H-bridge pre-driver is configured as two blocks so as to suit the width of an H-bridge driver Tr. The two blocks are line-symmetrically placed with a bias circuit interposed therebetween. One of the pre-driver blocks is laid out as a rectangle that is long in one direction and is short in a direction perpendicular to that direction. With this configuration, the pre-driver layout area can be reduced, and the cost of IC can be reduced. Furthermore, the symmetric placement enables matching of the impedance of interconnect from the pre-driver to the driver and stabilization of properties to be achieved.

A conveying driving device of the invention includes a first motor which transmits power to a drive shaft of a roller; a second motor which transmits power to the drive shaft along with the first motor at a torque smaller than that of the first motor; and a controller which sets each of drive current setting values of the first motor and the second motor so that a total value of a consumption current of the first motor and the second motor becomes minimal in a steady state in which the roller rotates at a constant setting speed.

While a stepping motor for conveying a paper is being driven, a first clocking section enables a counting control section to add a first predetermined value to a count value each time a first predetermined period of time elapses. When the count value reaches a first threshold value, a motor stop determination section stops the motor. A second clocking section enables the counting control section to subtract a second predetermined value from the count value each time a second predetermined period of time elapses when the motor is stopped. When the count value falls below a second threshold value smaller than the first threshold value, a motor drive resuming section resumes the operation of the motor. A third clocking section enables the counting control section to subtract a third predetermined value from the count value each time a third predetermined period of time elapses when the stepping motor is stopped in a state in which the count value is smaller than the first threshold value.

While a stepping motor for conveying a paper is being driven, a first clocking section enables a counting control section to add a first predetermined value to a count value each time a first predetermined period of time elapses. When the count value reaches a first threshold value, a motor stop determination section stops the motor. A second clocking section enables the counting control section to subtract a second predetermined value from the count value each time a second predetermined period of time elapses when the motor is stopped. When the count value falls below a second threshold value smaller than the first threshold value, a motor drive resuming section resumes the operation of the motor. A third clocking section enables the counting control section to subtract a third predetermined value from the count value each time a third predetermined period of time elapses when the stepping motor is stopped in a state in which the count value is smaller than the first threshold value.

The invention provides an intelligent moxibustion device, comprising a vertically disposed barrel, an ash tower buckled with the barrel, a moxa stick driving unit and an intelligent control unit disposed in the barrel; wherein the moxa stick driving unit comprises a moxa stick sleeve and a stepping motor disposed above the moxa stick sleeve; the stepping motor drives the moxa stick to move up and down through the transmission of a gear; the intelligent control unit comprises a battery disposed above the stepping motor for powering the entire moxibustion device, a circuit board fixed above the battery, and a temperature sensor disposed in the ash tower, the battery being connected to the circuit board to provide power to the circuit board, the circuit board being connected to the temperature sensor through input and output terminals.

The invention provides an intelligent moxibustion device, comprising a vertically disposed barrel, an ash tower buckled with the barrel, a moxa stick driving unit and an intelligent control unit disposed in the barrel; wherein the moxa stick driving unit comprises a moxa stick sleeve and a stepping motor disposed above the moxa stick sleeve; the stepping motor drives the moxa stick to move up and down through the transmission of a gear; the intelligent control unit comprises a battery disposed above the stepping motor for powering the entire moxibustion device, a circuit board fixed above the battery, and a temperature sensor disposed in the ash tower, the battery being connected to the circuit board to provide power to the circuit board, the circuit board being connected to the temperature sensor through input and output terminals.

A method for backlash compensation in motion control systems includes homing a payload of a motion control system, and performing a tooth-pitch non-uniformity procedure on the motion control system to identify a non-uniformity correction. A backlash lookup table is generated for use in backlash correction during normal operation of the motion control system. The backlash lookup table is generated using a training process that includes selecting a move sequence for operating the motion control system, and executing the move sequence with the non-uniformity correction. The training process further includes computing a backlash measurement describing backlash of one or more components of the motion control system during the move sequence, and storing the backlash measurement in the backlash lookup table.