JPS6010995B2 - Hanging load mass measuring device for robots, hoists, cranes, etc. - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method for automatically measuring the mass of a suspended load in order to control the speed of a movable body in a robot, hoist, crane, etc. using a speed pattern selected based on the mass of the suspended load. Concerning a measuring device.

In a previously filed patent application, the inventor proposed an invention for a device that controls the speed of a movable body using a speed pattern determined based on the weight of the suspended load. Since it uses a known weight detector, it is necessary to install a new weight detector at a predetermined location, and it also extracts mechanical displacement as an electrical signal, so inspection and adjustment are required frequently. There is concern that the failure rate will be relatively high after long-term use. The purpose of this invention is to visually measure the suspended load mass, which is proportional to the suspended load amount, using the drive system of the movable body, without directly detecting the suspended load amount using a weight detector. To provide a suspended lateral mass measuring device for a robot, hoist, crane, etc., which can accurately determine a speed pattern commensurate with the amount of suspended load by using the suspended mass to determine the speed pattern of a movable body. It is something.

Specifically, means for instantaneously generating a predetermined driving force in the drive source of the movable body that exceeds the static friction force of the movable body;
means for detecting the speed of a movable body instantaneously driven by a drive source and generating speed information; means for detecting a change in the speed of the movable body and generating movement distance information according to the change; It is an object of the present invention to provide a device for measuring the mass of a suspended load on a robot, hoist, crane, etc., which includes means for calculating the mass of a suspended load on a movable body based on distance information and a predetermined driving force applied to the movable body. Preferred embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a circuit block diagram showing an embodiment of the hanging fruit mass measuring device of the present invention, as well as a speed control system for a movable body, taking a hoist as an example.

In Fig. 1, 1 is a traveling rail as a stationary body, 2 is a cursor as a movable body, 3 is a parallel link mechanism for suppressing the swinging of the suspended load 5, 4 is a holding odor suspended from the cursor 2, and 6A is a Wire 1, 6B for moving cursor 2
7 is a wire for raising and lowering the retained odor 4.
A deceleration mechanism drives 6A, and 8 is a motor as a drive source.

An example in which the force-sol 2 is a movable body will be shown below, but the holder 4, which is raised and lowered by the wire 6B, may be used as a movable body and used in the speed control system. In the speed control system that controls the motor 8 based on the mass of the suspended load 5, 9 is a speed command generator that selects a speed pattern based on the measured mass and sends out a speed signal; 10 is an addition point; 11 is a speed controller, and 12 is a tachogenerator that feeds back the rotational speed of the motor 8 by one point.

The suspended mass measuring device of the present invention, which utilizes such a hoist and its speed control system, detects the speed of the cursor 2 and also detects changes in the speed of the cursor 2 using a tacho generator 13 as a means for generating speed information. As a means of generating movement distance information according to the change, a pulse generator 14 that generates unit distance pulses and a motor 8 are used to generate an instantaneous pulse that exceeds the static friction force of the cursor 2 (when the suspended load 5 is at its maximum rated weight). An instantaneous drive controller 15 as means for supplying driving power V, and information signals and set speed V from the tacho generator 13 and pulse generator 14. and set distance S. It is constructed with an arithmetic circuit 16 as a means for calculating the mass of the suspended load 5. The switch S is provided to operate the instantaneous drive controller 15, and the switch S2 disconnects the output of the speed controller 11 and supplies the output of the instantaneous drive controller 15 to the motor 8 during mass measurement. It is. Here, the principle of mass measurement by the apparatus of the present invention will be explained with reference to the graph of FIG.

The instantaneous drive controller 15 generates electric power that applies a constant force Fo in the form of a rectangular pulse as shown in FIG. is set to supply.

The magnitude of the driving force Fo applied to the cursor 2 must be greater than the static friction force (KIN) when the cursor 2 suspends the maximum rated load. By applying a driving force that exceeds this static frictional force (KIN), the cursor 2 is moved a small distance. Of course, the driving force Fo is larger than the force (K) of the cursor 2. Here, KI
is the coefficient of static friction, K2 is the coefficient of friction, and N is the drag force.
When an instantaneous driving force Fo is applied to the cursor 2 as shown in FIG. 2a, the cursor 2 causes an exponential speed change as shown in FIGS. 2b to d, for example.

Therefore, considering the amount of work W when the dynamic friction of cursor 2 is not considered, w=F.

・s: V2 (1) However, W: Work amount Fo = Driving force for the cursor (constant) S = Movement distance of the cursor V = Speed of the cursor m = Force - Mass of the suspended load including the sol, therefore mass m is Pan・S (2) m=-city-
It is required as.

From formula 21, driving force F.

There are three methods to find the mass m when given. 'ee As shown in Figure 2b, constant speed vo
Measure the distance s traveled when reaching
(3) How to obtain as follows.

‘.

) As shown in FIG. 2C, the speed v when reaching a certain distance So is measured, and m=empty=(bait・S.

) The method of finding the main (4).

As shown in Fig. 2d, the time t until reaching a certain distance so is measured, and the speed vo at this time is V.

=S. /t, so by substituting it into the above formula (①), m-person band: take away ■ Figure 3 shows an arithmetic circuit that calculates the mass m by measuring the moving distance S when the target reaches the constant speed vo. FIG. 2 is a circuit block diagram showing an embodiment of the part.

In FIG. 3, one input terminal of the comparator 17 is supplied with a predetermined velocity voo serving as a discrimination criterion, and the other input terminal is supplied with the cursor velocity vt from the tacho generator 13 as velocity information. When the speed vt matches the reference speed vo, the output of the comparator 17 changes from logic level "1" to "
0'', thereby prohibiting the passage of the unit distance pulse, which is information about the moving distance, from the pulse generator 14 and applied to the AND gate 18. Therefore, the unit distance pulses from the pulse generator 14 are counted until the comparator 17 is inverted, and the count content of the counter 19 is equal to the predetermined speed v.
The distance s is held at the time when the distance s is reached, and the second calculation unit calculates the mass m by executing the calculation according to the above-mentioned equation. FIG. 4 shows an embodiment of an arithmetic circuit unit for calculating the mass m by measuring the speed v when the vehicle reaches a certain distance So of the above-mentioned 'o}.

In FIG. 4, the counter 21 is the pulse generator 1
4 unit distance pulses are counted and the cursor movement distance St is supplied to one input terminal of the comparator 22. A predetermined distance So is supplied to the other input terminal of the comparator 22 as a discrimination criterion, and when both inputs match, a gate signal is given to the monostable multipipulator 23. The monostable multipipulator 23 is activated by this gate signal to produce a sampling pulse with a predetermined time width. On the other hand, the speed vt from the tacho generator 13 is input to the sample circuit 24, which is connected to the monostable multipipe generator 2.
3, the sampling pulse is received at a predetermined distance S. The speed when the cursor reaches v. is extracted, converted into a digital signal if necessary, and supplied to the arithmetic unit 26. Therefore,
The calculator 26 calculates the mass m by calculating the formula 41. FIG. 5 shows an embodiment of an arithmetic circuit unit for determining the mass m by measuring the time t until reaching the above-mentioned certain distance So.

In FIG. 5, the force counter 27 is connected to the pulse generator 1.
The unit distance pulses from 4 are counted and the cursor movement distance St is supplied to one input terminal of the comparator 28, and the other input terminal of the comparator 28 is supplied with a predetermined distance So as a discrimination criterion.
is supplied. The timer 29 is activated by a start signal derived from the instantaneous drive controller 25 shown in FIG. It is stopped by the output of the comparator 28 when reaching the predetermined distance So, and the time t until reaching the predetermined distance So is sent out. Therefore, the calculator 30 calculates the mass m by executing the calculation of the {5}th equation. Note that the calculation circuit 16 shown in FIG. 1 can calculate the mass of the movable body including the suspended load if it is equipped with any one of the circuit configurations shown in FIGS. Therefore, all of the circuits shown in FIGS. 3 to 5 may be provided, and the average value of their outputs may be taken as the measured mass m of the movable body. Furthermore, the arithmetic circuit 16 is not limited to the embodiments shown in FIGS. 3 to 5, and a microcomputer equipped with an arithmetic program for executing the arithmetic operations of equations {31 to [5] above may also be used.

In the above embodiments, the dynamic frictional force of the movable body is ignored as being extremely small, but in order to improve the accuracy of measuring the suspended load mass, the loss of the driving force Fo due to the dynamic frictional force may be taken into consideration.

That is, considering the sardine friction force, the above-mentioned formula '11 is W=F.
-S-leg-S pre-V2 (6) Since N=mg (however, g is the gravitational acceleration), scale winding g-S in m
(7) is obtained as.

Even when this {7th) equation is used, since each of Fo, x2, and g is a constant, the above-mentioned 'small.

} The mass of the suspended load including the movable body can also be calculated by any one of the methods described above. In addition, the working friction force (
K state) is proportional to the mass m, so a correction coefficient corresponding to the mass m is obtained in advance from the correlation with the mass m when the dynamic friction force is ignored and when it is included, and the The results of equations ~■ may be corrected using this correction coefficient.

In the above example, the tachometer generator 13 and the pulse generator 14, which serve as means for generating speed information and movement distance information of the movable body, are both connected to the cursor 2, which is the movable body.
may be connected to a motor 8 as a drive source, and the speed information of the cursor 2 may be obtained from the rotation speed of the motor 8.

Furthermore, the driving source is not limited to the motor 8, but may be based on hydraulic pressure or air pressure. As explained above,
The suspended load mass measuring device of the present invention is applicable to robots, hoists,
Since the mass of a suspended load including a movable body can be determined by applying the speed control system of a movable body such as a crane, it is possible to easily measure the mass by simply adding an electrical control system, and the mass of a suspended load including a movable body can be determined by simply adding an electrical control system. It is possible to accurately determine a speed pattern commensurate with the weight of the loaded load.

[Brief explanation of the drawing]

FIG. 1 is a circuit block diagram showing an embodiment of a speed control system using the suspended load mass measuring device of the present invention, taking a hoist as an example, and FIG. 2 is a circuit block diagram for explaining the mass measurement principle of the present invention. The graph diagrams, FIGS. 3, 4, and 5 are circuit block diagrams showing each embodiment of the arithmetic circuit of the mass measuring device according to the present invention. 1... Traveling rail, 2... Cursor,
3... Parallel link mechanism, 4... Holding odor, 5
...... Hanging load, 6A, 68... Wire 1, 7.
...Deceleration mechanism, 8...Motor, 9...Speed command generator, 10...Adder, 11...Speed controller, 12, 13... Tachometer generator, 14...
...pulse generator, 15...instantaneous drive controller,
16... Arithmetic circuit, 17, 22, 28...
...Comparator, 18...And gate, 19,2
1,27... Power unwind, 20,26,. 30... Arithmetic unit, 23... Monostable multipipulator, 2
4...Sample circuit, 29...Timer. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] 1. Means for instantaneously generating a predetermined driving force exceeding the static friction force of the movable body in the drive source of the movable body, and means for detecting the speed of the movable body instantaneously driven by the drive source and generating speed information. , a means for detecting a change in the speed of the movable body and generating movement distance information according to the change; and a means for detecting a change in the speed of the movable body and generating movement distance information according to the change; A device for measuring the mass of a suspended load on a robot, hoist, crane, etc., consisting of a means for calculating mass.