Abstract: A plurality of step time tables consisting of a sequence of step times defining intervals between steps and thus a velocity profile to be executed by a stepper motor are stored in a first memory. A step table defining a plurality of identical sequences of excitation pattern for driving a stepper motor is stored in a second table. Identical DMA channels output the step times to a timer and the plurality of exitation patterns to a buffer. The timer measures the duration of the step times and when each step time expires generates a trigger signal which initiates the transfer of the next step time and next excitation pattern through the respective DMA channels. The buffer includes a control register which selects one excitation pattern from the plurality of excitation patterns output from the step table to be output for control of a selected one of a plurality of motors connected to the buffer.

Abstract: A motor speed controller for use with dc motors, such as found in model (slot) cars, is provided by a plurality of pairs of oppositely-poled voltage-sensitive threshold conduction devices which are selectively connected so as to be controllably inserted between a source of operating voltage and the dc motor. In a preferred embodiment of the invention, the voltage-sensitive threshold conduction devices advantageously comprise a series connection of diode bridges which are sequentially included in the energizing path of the motor.Furthermore, the controller provides a speed sensitive brake function by controllably connecting at least one voltage-sensitive threshold conduction device across the windings of the dc motor. When so connected, this allows the voltage generated by the spinning motor to cause the voltage-sensitive threshold conduction device to be conductive until the motor speed slows to the point that the generated voltage no longer causes the device to conduct.

Abstract: A parallel structure manipulator device for displacing an object in a cylindrical work space about a predetermined axis (X) includes at least three drive mechanisms (A, B, C) interposed between a base (2) and a moving element (1). Two of the mechanisms (A, B) each include: mover (V) movable along a circular path (L) in a transverse plane perpendicular to the axis (X); a connecting rod (7) extending between the mover and the element (1) and connected thereto by a hinge (8) capable of two-directional rotation; and an attitude transmission member (9) associated with the connecting rod for maintaining the element (1) parallel to the transverse plane. The mechanisms (A, B) act together on the element (1) to define its angular position about the axis (X) and its distance (D) from a notional axis (W) passing through those ends of the connecting rods that are connected to the mover. A third mechanism (C) is free to rotate relative to the base about an axis parallel to the axis (X) and away from the transverse plane.