Elevator – industrial lift truck – or stationary lift for vehicle – Having specific load support drive-means or its control – Includes control for power source of drive-means
Patent
1998-02-05
1999-09-28
Nappi, Robert E.
Elevator, industrial lift truck, or stationary lift for vehicle
Having specific load support drive-means or its control
Includes control for power source of drive-means
187393, 187293, B66B 134, B66B 124
Patent
active
059592664
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
This invention relates to a speed control apparatus for an elevator car.
BACKGROUND ART
In a roped-elevator, a car connected with a counter weight by a rope travels up and down with a hoist machine winding the rope up and down. A conventional speed control apparatus for the roped-elevator to control the speed of the car is shown in FIG. 8. A speed convert circuit 14 inputs a car speed command value Vcref and converts the car speed command value Vcref to a motor speed reference value Vmref1, where the motor drives the hoist machine. The motor speed reference value Vmref1 is calculated by using constants including a diameter and a rotational angular velocity of a sheave of the hoist machine. A follow-up control circuit 15 inputs a deviation value Vce1 between the motor speed reference Vmref1 and a actual motor speed Vm from a motor speed detecting circuit 5 and calculates a motor speed correction signal Vce2 for the actual motor speed Vm following-up the motor speed reference value Vmref1. This follow-up control circuit 15 is provided with a P (proportional) factor which outputs a signal proportional to the deviation value Vce1 and an I (integral) factor which outputs a signal proportional to a cumulative value of the deviations Vce1.
A motor 16 is a type of an induction motor for driving the elevator. A power from the motor is transmitted to an elevator mechanical system 4 and a car speed Vc changes. Here, the elevator mechanical system 4 represents the whole mechanical system of the elevator including the rope, the car and the counter weight. A resolver is used as the motor speed detecting circuit 5 and it outputs pulses where the number of the pulses per unit time is proportional to its rotational speed.
A vibration suppress circuit 17 in-puts a deviation Vrip (vibration components) between the actual motor speed Vm from the motor speed detecting circuit 5 and a presumed motor speed Vmobs from a motor speed presuming circuit 18 and outputs a compensation component signal Vb against the vibration. FIG. 9 shows an inner schematic structure of the vibration suppress circuit 17. The vibration suppress circuit 17 is provided with a filter circuit 19 for eliminating a vibration component of the motor speed and a gain setting circuit 20 for multiplying the vibration component by a gain to output the vibration compensation signal Vb. The filter circuit 19 defines the most pertinent filter constant based on a car position detected signal y from a car position detecting circuit 10, and passes only a given frequency component in the deviation signal Vrip of the vibration between the actual motor speed Vm and the presumed motor speed Vmobs. The gain setting circuit 20 defines the most pertinent gain based on the car position detected signal y and a car load detected signal mc from a car load detecting circuit 9 and outputs the vibration compensation signal Vb calculated by multiplying an output from the filter circuit 19 by the gain. As set forth above, the vibration suppress circuit 17 calculates the vibration compensation signal Vb for suppressing the vibration caused by the changes of the car position and the car load and adds the signal Vb on a motor speed correction signal Vce2 outputted from the follow-up control circuit 15. As a result, the added signal (Vce2-Vb) is inputted as a motor speed reference value Vmref2 to the motor 16 and the motor 16 can rotate smoothly without vibrations.
Here, the car position detecting circuit 10 includes a pulse generator mounted on a governor and evaluates the car position from the number of the pulses generated proportionally to a distance of movement of the car. The car load detecting circuit 9 includes a load cell (or a linear-former) mounted under the floor of the car and outputs a voltage signal proportional to the car load. The detecting circuits 9 and 10 input their output signals mc and y into the vibration suppress circuit 17.
Another follow-up control circuit 21 calculates, based on a deviation signal Vmobs1 between the motor speed reference valu
REFERENCES:
patent: 5635689 (1997-06-01), Shepard et al.
patent: 5824975 (1998-10-01), Hong
Kabushiki Kaisha Toshiba
Nappi Robert E.
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