GB1565459A – Speed control system of elevator
– Google Patents
GB1565459A – Speed control system of elevator
– Google Patents
Speed control system of elevator
Download PDF
Info
Publication number
GB1565459A
GB1565459A
GB50146/77A
GB5014677A
GB1565459A
GB 1565459 A
GB1565459 A
GB 1565459A
GB 50146/77 A
GB50146/77 A
GB 50146/77A
GB 5014677 A
GB5014677 A
GB 5014677A
GB 1565459 A
GB1565459 A
GB 1565459A
Authority
GB
United Kingdom
Prior art keywords
speed
acceleration
pattern
car
speed pattern
Prior art date
1976-12-01
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
GB50146/77A
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Mitsubishi Electric Corp
Original Assignee
Mitsubishi Electric Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
1976-12-01
Filing date
1977-12-01
Publication date
1980-04-23
1977-12-01
Application filed by Mitsubishi Electric Corp
filed
Critical
Mitsubishi Electric Corp
1980-04-23
Publication of GB1565459A
publication
Critical
patent/GB1565459A/en
Status
Expired
legal-status
Critical
Current
Links
Espacenet
Global Dossier
Discuss
Classifications
B—PERFORMING OPERATIONS; TRANSPORTING
B66—HOISTING; LIFTING; HAULING
B66B—ELEVATORS; ESCALATORS OR MOVING WALKWAYS
B66B1/00—Control systems of elevators in general
B66B1/24—Control systems with regulation, i.e. with retroactive action, for influencing travelling speed, acceleration, or deceleration
B66B1/28—Control systems with regulation, i.e. with retroactive action, for influencing travelling speed, acceleration, or deceleration electrical
B66B1/285—Control systems with regulation, i.e. with retroactive action, for influencing travelling speed, acceleration, or deceleration electrical with the use of a speed pattern generator
Description
PATENT SPECIFICATION ( 11) 1 565 459
O ( 21) Application No 50146/77 ( 22) Filed 1 Dec 1977 t ( 31) Convention Application No 51/144339 ( 19) ( 32) Filed 1 Dec 1976 in ( 33) Japan (JP) ( 44) Complete Specification published 23 April 1980 _( 51) INT CL 3 B 66 B 1/28 H ( 52) Index at acceptance G 3 N 265 B DB ( 54) SPEED CONTROL SYSTEM OF ELEVATOR ( 71) We, MITSUBISHI DENKI KABUSHIKI KAISHA, a Japanese Company, of 2-3, Marunouchi 2-chome, Chiyoda-ku, Tokyo, Japan, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: 5
The present invention relates to a speed control system for an elevator.
In order to illustrate a speed pattern of an elevator, reference will now be made to Figure 1 of the accompanying drawings, which is a graphical representation of velocity and acceleration against time for movement of an elevator car 10 It is desirable that, as shown in Figure 1, the maximum accelerating values (the absolute values of acceleration) at the accelerating and decelerating times are previously set at fixed values al and a 2 and a speed pattern Vo Va Vb Vc Vd Ve is formed so that the acceleration pattern depicts a pattern Ao Aa Ab Ac Ad Ae, for example The maximum acceleration (the absolute value of acceleration) at the 15 deceleration is independent of the type of operations With the reference of the time that the car reaches a target stoppage position, the speed pattern for an acceleration pattern A’o A’a A’b A’c Ad Ae is V’o V’a V’b V’c Vd Ve and the speed attern for an acceleration pattern A”o A”a A”b A”c Ad Ae is V”o Va V”b V”c Vd Ve These speed patterns are laid on a straight line 20 V Vc V’c V Wc Vd as indicated by a broken line in the constant acceleration region at the deceleration.
The car is accelerated along a speed pattern Vo Va Vb and as it reaches the deceleration decision point Vb, a speed pattern Vb Vc of the time reference as shown is generated At this time, various factors cause it to deviate from the speed 25 pattern V M Vat the point Vc, to possibly cross the latter In such a case, the car is shocked to result in the discomfort of passengers.
Accordingly, the primary object of the invention is to provide a speed control system of elevator by which two speed patterns smoothly overlap each other to eliminate a shock to the car and thus to ensure the comfort of passengers, with a 30 view to overcoming the above-mentioned disadvantage.
According to the invention there is provided a speed control system for an elevator car, the system comprising means in which a first speed pattern, being an integration of an acceleration pattern, and a second speed pattern, decreasing at a constant acceleration for a certain distance before a stoppage point, are set up; 35 comparing means which detect the difference in magnitude between said first and second speed patterns; means which determine when an elevator car reaches a deceleration decision point; means reducing said acceleration pattern stepwise after the car reaches the deceleration point in accordance with the comparing means output, integration of said reducing acceleration being used as said first 40 speed pattern; and means which operate the car in accordance with the first speed pattern before the decision point and, when the car reaches the deceleration decision point, control the car in accordance with the first speed pattern before the first and second speed patterns are coincident and then in accordance with the second speed pattern after they are coincident 45 The present invention will be better understood from the following description taken in connection with the accompanying drawings in which:
Figure 1 shows two graphs to illustrate the relationship of acceleration pattern vs speed pattern of elevator; Figure 2 shows two graphs to illustrate the relationship of acceleration pattern vs speed pattern of an embodiment of a speed control system of an elevator according to the invention; 5 Figure 3 is a set of graphs to illustrate the relationship of the speed pattern immediately before the car stops and the car speed and the acceleration pattern; Figure 4 is a block diagram of an embodiment of the speed control apparatus of an elevator according to one embodiment of the invention; and Figure 5 is a set of graphs for illustrating the relationship of acceleration 10 pattern when the speed reaches the rating speed in the embodiment of the invention.
An embodiment of the invention will be given with reference to Figs 2 through 4.
In Fig 2, Ap designates an acceleration pattern of three-step staircase shape in 15 which the absolute values of the maximum accelerations at acceleration and deceleration are designated by a and each step has an acceleration interval l/3 a and an equal time interval T (generally, increase of number of steps makes the speed pattern smooth) Vp designates a first speed pattern.
For ease of explanation, the operating condition of the elevator will be divided 20 into 10 regions: the stoppage region designated by STO; the acceleration 1/3 a region from start time 0 to time T designated by ST 1; the acceleration 2/3 a region from T 1 to T 2 and soon by ST 2; the maximum acceleration a region by ST 3 continuous to the time T 3 to start the deceleration to stop the car at the stop target floor position (hereinafter referred to as a stoppage point); the acceleration 2/3 a 25 region continuing its successive deceleration to time T 4 by ST 4; the acceleration 1/3 a continuous till time Ts by S Ts; the acceleration 0 region till T 6 by ST 6; the negative acceleration -1/3 a continuous to time T 7 by ST 7; the negative acceleration -2/3 a region till time T 8 by ST 8; the region designated by ST 9 including the acceleration -a region and another region where the acceleration rectilinearly 30 changes from -a to 0 for car stop Further, an instruction speed value at a point V 3 on the first speed pattern Vp at time T 3 is represented by character V 3; instruction speed values at points V 4 to V 9 by characters V 4 to V 9 The car running distances in the respective regions ST 4 to ST 8 (for example, the running distance of ST 4 corresponds to the area defined by T 3, V 3, V 4, T 4 and T 3) are designated by 35 characters Sa, Sb, Sc, Sd and Se, respectively The distance of the region ST 9 corresponding to a triangle area defined by T 8, V 8, T’10 and T 8 is denoted by Sf The area enclosed by Sf, T’o, Vg, T 10 and T’10 by Sx These instruction speed values and areas are given below V 3 =/ 40 V 4 =V=V 3 + 2/3 a T Vs=V=V 4 + 1/3 a T=V 3 +a T Sa=Se= I/3 a T 2 +V 3 T Sb=Sd= 5/6 a T 2 +V 3 T Sf=a T 2 +V 3 T 45 The remaining distances at time T 4 to T 8 till the stoppage point, designated by 54 to S are given Ss=Sf+Sx 57 =Sf+Sx+Se=Sf+Sx+ l/3 a T 2 +V 3 T Se=Sf+Sx+Se+Sd=Sf+Sx+ 7/6 a T 2 + 2 V 3 T 50 Ss=Sf+Sx+Se+Sd+Sc=Sf+Sx+ 13/6 a T 2 + 3 V 3 T 54 =Sf+Sx+Se+Sd+Sc+Sb=Sf+Sx+ 3 a T 2 + 4 V 3 T The rectilinear speed pattern V’3 V V, V’10 indicated by dotted and alternate long and short dash lines is given by an equation ( 1) with respect to the remaining distance Sr till the stoppage point when the car is decelerated at a fixed negative 55 acceleration -a.
V=V/2 a(Sr-Sx) ( 1) The remaining distance 53 at time T 3 to start to reduce the acceleration in order to stop the car at the stoppage point, is given 1,565,459 53 =Sf+Sx+Sa+Sb+Sc+Sd+Se The distance 53 is smaller than the area defined by T 3, V’3, Vg, T 10 and T 3 The speed curve obtained by substituting the respective remaining distances at times T 3 to T 8 into the fupction of the speed distance by the equation ( 1), is traced to be a broken line V” 3 V” 45 V” 6 V ” 7 V 8 5 Speed differences AV 4, AV,, AVR, and AV, at times T 4 to T 7 between the curves V” 3 ‘ V V 4 Vt V” 6 V, V” 8 and V 3 V 4 V 5 V 6 V 7 V 8 are \V+ Za( 54 Sx) -V 4 =V 3 + 3 a T+ 4 Va T -V 3-2 a T V, ‘-12 a(Sr-5)-V Vz t3 V -a T V= -2 a( 57 >S-‘ S < 87-V:+ ai T 2 +V 3 T V 3-2 ai F 3 The speed differences AV 4, AV 5, A Va and V, are the function of the instruction speed value V 3 at the stoppage decision time T 3 and become large as the value V 3 is large.
Let us now study deviation of the speed difference depending on the 15 instruction speed value V 3 at the stoppage decision point When T= 0 4 sec and a=l O m/sec 2, in the car operation for one floor interval of 3 m, the instruction speed value V 3 is approximately 1 O m/sec and, when the rating speed is 10 m/sec the V is 9 6 m/sec to reach the rating speed When the speed differences of the respective cases, e g AV 4 is calculated, we obtain AV 44-1 23 for one floor interval 20 operation and AV 4 = 1 53 for the operation to reach the rating speed Therefore, the speed deviation is only about 20 %.
The speed differences AV 4, A Vs, AV 6 and AV 7 in an ideal one floor interval operation are previously set up At time T 3 of the stoppage decision point V 3, the acceleration is reduced from the maximum value a to 2/3 a A second speed pattern 25 Vm, previously stored in terms of the function of speed and distance, and the first speed pattern Vp are compared Then, as the difference therebetween equals the pregiven speed difference AV 4, the acceleration is reduced to be l/3 a And when the speed difference thus obtained equals the A Vs, the acceleration is reeduced to be zero In this manner, this comparing process will be repeated for the respective 30 pregiven speed differences AV 4, A Vo, AV 6, and AV 7 Along with this, the acceleration is reduced successively as of A 8 A 7 A 8 As A Ao This reducing acceleration is integrated to obtain the first speed pattern Vp ' Finally, in the region ST 8 of the acceleration -2/3 a, if the acceleration maintains its-2/3 a, both the speed patterns Vp and Vm will necessarily cross since 35 the acceleration of the second speed pattern Vm is -a Accordingly, after the speed values of both the speed patterns Vp and Vm coincide with each other the second speed pattern Vm is treated as the instruction speed pattern As a result, the speed pattern is smooted wthly changed without being accompanied by the discomfort of passengers, from the first speed pattern of time reference at the acceleration to the 40 second speed pattern of distance reference at the deceleration, and additionally the car lands at the stoppage point with a high accuracy i Incidentally, the speed/distance function of the second speed pattern previously stored must take account of the time lag of the elevator control system.
Referring to Fig 3, and example will be described of the speed/distance 45 function of the second speed pattern Vm to be stored A In the figure, Vmy 9 '1 V,0 is'the second speed pattern, Vr Y Vrg V'rg Ti O an actual speed of the car, A Ar Tro the acceleratio the the second speed pattern, and A Ar Ttr O an actual acceleration of the car.
In this example, it is assumed that the time delay of the elevator control system 50 in the fixed acceleration region of a acceleration is constant with Td, the acceleration of the second speed pattern and the car acceleration exhibit a 1,565,459 rectilinear decrease, and the time lag is reduced zero at the time To the car lands the stoppage point That is, the second speed pattern V, V' T 10 and the actual speed pattern Vr V'9 T 10 are of the second order curve With designation of Tc for the time interval between the time points, T'9 and To, Vc for the second speed value at time Tg, and V'c for the actual speed of the car, the following relations hold 5 Vc= 1/2 a Tc V'c=Vc+a Td The remaining distances from the time points T 9 and T'9 to the stoppage point (corresponding to the area defined by T 9 Vr 9 T 10 T 9 and T'9 V'r 9 To T'9), designated 10 by 59 and S'9 are 10 S=l I/6 a Tc 2 + 1/2 a(Tc+Td)Td S'= l/6 a Tc 2 Accordingly, the speed/distance function to be stored is given below with designation of Sr for the remaining distance till the stoppage point and Umrn for the stored speed 15 In the region O
