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
Reexamination Certificate
1999-08-30
2001-11-06
Salata, Jonathan (Department: 2837)
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
C187S291000
Reexamination Certificate
active
06311802
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an elevator system, and in particular to a velocity instruction generation apparatus for a car of an elevator system and a velocity control method which are capable of decreasing an arithmetic operation time, operation amount and operation error and controlling the velocity of a car in real time by integer-operating a velocity instruction for controlling the velocity of the car.
2. Description of the Conventional Art
Generally, in an elevator system, a Direct Current (DC) motor or an induced motor moves an elevator car connected with the rotation axis of the motor through a cable or a pneumatic mechanism. The driving operation of the motor should be properly controlled so that an elevator car is accurately stopped and started from a certain floor of a building. In order to properly control the driving operation of the motor, variables related to the driving operation of the motor should be properly defined, and the units of the variables should be defined. The variables and the units of the variables are defined in the specification of an elevator system. Generally, the specification of the elevator system is defined in the MKS unit.
The operation controller formed of a microcomputer chip generates a velocity instruction signal of the MKS system in real time without changing the units of the constants based on the constants of the system specification of the MKS system and controls the operation of the car for thereby preventing a certain error during the operation of the elevator system, so that a certain elevator car operation is implemented.
The elevator car velocity instruction generation apparatus for a conventional elevator system will be explained.
FIG. 1
is a view illustrating a schematic block diagram of the conventional elevator system which includes an elevator car
180
for boarding passengers thereon, a door zone plate
170
installed at each floor for indicating an absolute floor, a balance weight
160
connected with the car
180
by a rope through a sheave of a winding machine (not shown), a motor
150
for upwardly and downwardly moving the car
180
, a rotary encoder
140
for outputting pulses as rotating the shaft of the motor
150
, a velocity controller
120
for outputting a velocity control signal for controlling the driving operation of the motor
150
in real time in accordance with the position of the car
180
, an amplifier
130
for supplying an electric power to the motor
150
in accordance with the velocity control signal, a position detector
190
installed at the upper portion of the car
180
for detecting an absolute floor by detecting the door zone plate
170
, and an operation controller
110
for receiving an output signal from the position detector
190
and pulses outputted from the rotary encoder
140
, computing the velocity instruction signal for controlling the velocity of the car
180
and outputting to the velocity controller
120
.
FIG. 2
is a view illustrating a conventional velocity instruction generation apparatus which includes a signal processing unit
111
for controlling an elevator system and computing a running distance of a car
180
, an EEPROM
112
for storing the specification of the elevator system, a ROM
113
for storing a program for controlling the elevator system, a RAM
114
for temporarily storing a computation data when computing the velocity instruction signal, and a counter
115
for counting pulses.
In detail, the signal processing unit
111
includes a pulse input unit
11
for receiving a pulse signal outputted from the rotary encoder
140
, a traveling distance computation unit
12
for counting the number of pulses received into the pulse input unit
11
and computing the traveling distance of the car
180
, a floor height computation unit
13
for judging the present position of the car
180
based on the distance computed by the traveling distance computation unit
12
, a car stop determination computation unit
14
for determining the stop position of the car
180
, a time based velocity instruction computation unit
15
for transferring a velocity instruction signal corresponding to time stored in the EEPROM
112
at the time of the operation start point of the car
180
to the velocity controller
120
, and a distance based velocity instruction computation unit
16
for transferring a velocity instruction signal corresponding to the distance stored in the EEPROM
112
to the velocity controller
120
with respect to the stop instruction of the car
180
.
The operation of the velocity instruction generation apparatus for a conventional elevator system will be explained.
When a passenger calls the car
180
at a certain floor, the signal processing unit
111
of the operation controller
110
performs an operation control program stored in the ROM
113
and transfers the velocity instruction signal V(t) to the velocity controller
120
. The velocity controller
120
which received the velocity instruction signal v(t) outputs a velocity control signal to the amplifier
130
, and the amplifier
130
controls the rotation speed of the motor
150
based on the velocity control signal.
When the car
180
begins to move, the rotary encoder
140
connected with the shaft of the motor
150
outputs pulses. The running distance computation unit
12
receives the pulses via the pulse input unit
11
and computes the running distance of the car
180
by counting the number of pulses. The floor computation unit
13
computes the current floor and the previous floor of the moving or moved the car
180
based on the computed running distance of the running distance computation unit
12
.
The stop determination computation unit
14
which receives the value corresponding to the current position of the car and the value corresponding to the previous floor outputted from the floor computation unit
13
computes the control values stored in the EEPROM
117
and the thusly received values and determines the destination floor at which the car
180
arrives.
When the car
180
moves to approximately the destination floor, the position detector
190
installed on the upper portion of the car
180
detects the door zone plate
170
. When the position detector
190
accurately detects the position of the door zone plate
170
, a certain output signal is outputted to the signal processing unit
111
. Therefore, the time based velocity instruction computation unit
15
of the signal processing unit
111
is inactivated, and the distance based velocity instruction computation unit
16
is activated, so that the car
180
is stopped. The distance based velocity instruction computation unit
15
reads the distance based velocity instruction signal v(t) stored in the EEPROM
112
and outputs the velocity instruction signal v(t) to the velocity controller
120
, and the velocity controller
120
outputs a velocity control signal, so that the rotation of the motor
150
is decreased and the car
180
arrives at the destination floor. When the car
180
arrives at the destination floor, the rotation of the motor
150
is stopped.
With an elevator system specification, the elevator car velocity instruction generation aparatus in accordance with the conventional art will be explained as follows.
In the specification of an elevator system, for example, if the maximum jerk Jmax is defined as 1 m/s
3
, the maximum acceleration Amax is defined as 1 m/s
2
, the maximum velocity Vmax is defined as 2 m/s, and the minimum height of a floor is defined as 2.5 m, the operation of the elevator car velocity instruction generation aparatus in accordance with the conventional art will be explained.
The velocity controller
120
controls the rotation of the motor in three types as shown in
FIGS. 3 through 5
in accordance with the running distance of the car.
FIG. 3
illustrates the profiles of a velocity of a car, an acceleration and a jerk when a car runs long distance over the time, and the car decelerates at a certain time after the car reached the maximu
Choi Byoung Wook
Kim Ji Heon
LG-Otis Elevator Company
Salata Jonathan
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