Servomechanisms that decelerates properly on approach to limit of travel

Claim 2

A servomechanism having an input circuit including an amplifier for delivering voltage to the input of a servo motor system for moving a load through a path limited by end stops, the servomechanism also including means for reducing the servo output speed at a critical position before an end stop, said means includIng a load position sensor, and voltage limiting means inserted in said input circuit responsive to signals delivered by the position sensor, said voltage limiting means comprising a pair of transistors each connected in parallel to the amplifier at one side through a common emitter resistor, and at the other side through respective oppositely poled diodes, said transistors being arranged to receive base biasing voltages which are derived under the control of the position sensor, and collector biasing voltages which are derived through the respective diodes from the amplifier output such that said transistors are switched on and off at required different times in the load traversal.

Claim 3

A servomechanism having an input circuit including an amplifier for delivering voltage to the input of a servo motor system for moving a load through a path limited by end stops, the servomechanism also including means for reducing the servo output speed at a critical position before an end stop, said means including a load position sensor, and voltage limiting means inserted in said input circuit including a reference voltage source in combination with electronic switching means arranged within the feedback loop of the amplifier and under the control of the position sensor and of the amplifier output, said voltage limiting means comprising a pair of transistors each connected in parallel to the amplifier at one side through a common emitter resistor, and at the other side through respective oppositely poled diodes, said transistors being so biased by voltages derived from the amplifier output and by potentials under the control of the position sensor that said transistors are switched on and off at required different times in the load traversal, said reference voltage source being constituted by the sum of the series voltages across the respective transistor when turned of and saturated, the respective diode and the common resistor.

Claim 4

A servomechanism having an input circuit including an amplifier for delivering voltage to the input of a servo motor system for moving a load through a path limited by end stops, the servomechanism also including means for reducing the servo output speed at a critical position before an end stop, said means including a load position sensor, and voltage limiting means inserted in said input circuit including a reference voltage source in combination with electronic switching means arranged within the feedback loop of the amplifier and under the control of the position sensor and of the amplifier output, said voltage limiting means comprising a pair of transistors each connected in parallel to the amplifier at one side through a common emitter resistor, and at the other side through respective oppositely poled diodes, said transistors being so biased by voltages derived from the amplifier output and by potentials under the control of the position sensor that said transistors are switched on and off at required different times in the load traversal, said reference voltage source being constituted by the sum of the series voltages across the respective transistor when turned of and saturated, the respective diode and the common resistor.

Claim 5

A servomechanism comprising a. a velocity feedback servosystem for moving a load through a path limited by end stops in response to a velocity demand signal applied at an input to said servosystem; b. an input circuit including an amplifier for receiving a signal representing a load velocity selected by an operator and for delivering said velocity demand signal to said input of the servosystem; and c. means for reducing the speed of the load at a critical position before an end stop, said means including a load position sensor and voltage limiting means connected to said input circuit at the output of the amplifier and responsive to signals delivered by the load position sensor to reduce the said velocity demand signal at the input to the servosystem to a preset maximum level when the load reaches said critical position, and thereby reduce the speed of the load to a preset value as the load approaches said stop from said critical position.

Claim 6

A servomechanism comprising a. a velocity feedback servosystem for moving a load through a path limited by end stops in response to a velocity demand signal applied at an input to said servosystem; b. an input circuit including an amplifier for receiving a signal representing a load velocity selected by an operator and for delivering said velocity demand signal to said input of the servosystem; and c. means for reducing the speed of the load at a critical position before an end stop, said means including a load position sensor and voltage limiting means connected to said input circuit at the output of the amplifier and responsive to signals delivered by the load position sensor to reduce the said velocity demand signal at the input to the servosystem to a preset maximum level when the load reaches said critical position, and thereby reduce the speed of the load to a preset value as the load approaches said stop from said critical position.

Claim 7

A servomechanism according to claim 3, wherein the transistors are arranged in a feedback loop of the amplifier with a common emitter connection to said common resistor.