JPH0798637B2 - Balanced equipment safety circuit - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a balanced cargo handling device, and more particularly to ensuring safety when a load suddenly changes, such as when a work falls or jumps during a balanced operation.

(Prior Art) As a conventional technology, for example, as disclosed in Japanese Patent Application No. 62-283159, there is a technology that instantaneously judges a sudden change in the load and stops the sudden movement of the load.

(Problems to be Solved by the Invention) In a balanced cargo handling apparatus, there is often a problem that safety is threatened by a sudden change in load during balanced operation or a shock during work, and workability is impaired. The present invention is
For the purpose of solving this problem, the present invention provides a technique for sensitively judging and distinguishing a sudden change in load or impact without impairing safety and workability.

(Means and Actions for Solving the Problems) In the present invention, in order to solve the above problems, the first
Of the invention, an actuator for raising and lowering a load, a drive circuit for driving the actuator, a force detector for detecting the load, an acceleration detector for detecting the acceleration of the load, and a speed detector for detecting the actuator speed, In a balanced cargo handling device equipped with a position detector that detects the actuator position and a speed commander that inputs a speed command, the differential value (dFe / dt) of the signal obtained from the signal Fe from the force detector When,
A signal (dθ / dt) from the speed detector is input, and the absolute value of the differential signal (dFe / dt) of the force detector is a predetermined threshold value ε.
Greater than (dFe / dt) and the signal from the speed detector (d
When the absolute value of (θ / dt) is larger than a predetermined threshold value ε (dθ / dt), (a) the equilibrium operation is temporarily stopped and the signal θ from the position detector, the velocity signal (dθ / dt),
And a negative feedback of the acceleration signal a, or (b) a negative force feedback for multiplying the difference between the signal Fe from the force detector in the equilibrium operation and the load memory value Wφ which has stored this signal Fe for a predetermined time. This is a safety circuit for a balanced cargo handling apparatus, which comprises control means for controlling the gain K by outputting a value smaller than that during normal balanced operation.

A second invention is an actuator for lifting and lowering a load,
A drive circuit that drives the actuator, a force detector that detects a load, and an acceleration detector that detects a load acceleration,
In a balanced cargo handling device equipped with a speed detector that detects the speed of the actuator, a position detector that detects the position of the actuator, and a speed commander that inputs the speed command,
The differential value (dFe / dt) of the same signal obtained according to the signal Fe from the force detector and the signal (dθ / dt) from the speed detector are input, and the differential signal (dFe / dt) of the force detector is input. ) Is greater than a predetermined threshold ε (dFe / dt), and the absolute value of the signal (dθ / dt) from the speed detector is predetermined ε (d
θ / dt) is larger than the load memory value φ that stores the signal Fe from the force detector during equilibrium operation for a predetermined time.
If the absolute value of the difference from the signal Fe from the force detector is continuously smaller than a predetermined threshold value εemg for a predetermined time T0 or more, it is determined that the load is temporary and the normal force When the feedback gain K is output to continue the balanced operation, and the load is continuously large for the predetermined time T0 or more, it is determined that the load is continuous and the balanced operation is stopped, and the signal θ from the position detector is stopped. The velocity signal (dθ / dt) and the acceleration signal a are negatively fed back, or the difference between the signal Fe from the force detector in the equilibrium operation and the load memory value Wφ stored for a predetermined time of this signal Fe is multiplied. This is a safety circuit for a balanced cargo handling apparatus, which comprises control means for controlling the force negative feedback gain K by controlling whether it is output smaller than during normal balanced operation.

The first aspect of the present invention having the above structure operates as follows.

The absolute value of the differential signal (dFe / dt) of the force detector is larger than a predetermined threshold value ε (dFe / dt), and the absolute value of the signal (dθ / dt) from the speed detector is a predetermined threshold value ε ( If the load Fe suddenly changes when the speed (dθ / dt) is large, (a) the equilibrium operation is temporarily stopped, and the position signal θ, the speed signal (dθ / dt), By negatively feeding back the acceleration signal a, or (b) by outputting the force negative feedback gain K, which is once multiplied by the difference between the signal Fe in the balanced operation and the load memory value Wφ, smaller than that in the normal balanced operation. Control to prevent sudden movements of.

Further, the second invention having the above-described structure operates as follows.

The absolute value of the differential signal (dFe / dt) of the force detector is larger than a predetermined threshold value ε (dFe / dt), and the absolute value of the signal (dθ / dt) from the speed detector is a threshold value ε (dθ / dt), that is, when the speed (dθ / dt) is large, the load Fe
When the load suddenly changes, the load memory value Wφ and the force signal during equilibrium operation
If the absolute value of the difference from Fe is continuously smaller than a certain threshold value εemg for a given time T0 or more, it is determined that it is a temporary sudden load, and equilibrium operation is continued by the normal force negative feedback gain K. However, if the load is continuously large for the predetermined time T0 or more, it is determined that the load is a continuous sudden change, and the equilibrium operation is stopped, the signal θ from the position detector, the speed signal (dθ / dt),
And the acceleration signal a are negatively fed back, or the force negative feedback gain K, which multiplies the difference between the signal Fe from the force detector in balanced operation and the load memory value Wφ, is output smaller than in normal balanced operation. (Example) The present invention is configured by the following (1) to (3) in response to a sudden load change during equilibrium operation or a shock during work. It enables sensitive detection of sudden changes in load without compromising the workability and workability.

(1) When the load suddenly changes, the difference between the differential signal Fe of the force detector and the stored value of the load and the signal from the force detector is large.

(2) On the other hand, at the time of impact, the differential signal Fe of the force detector is large, but the difference between the load memory value of the load and the signal from the force detector is only momentarily large, and thereafter becomes almost zero.

(3) Distinguishing between a shock or sudden load change and a normal working state,
After that, the impact and the sudden change in load are judged from the above (1) and (2).

FIG. 1 shows the overall configuration of an embodiment of the present invention.

The structure and operation shown in FIG. 1 are shown in detail in Japanese Patent Application No. 62-288343 except for the safety circuit.

The structure and operation of the safety circuit, which is a feature of the present invention, is shown in FIG.

The safety circuit works in conjunction with the speed command selection circuit,
This circuit operates when balanced operation is selected, and in other cases, the same as when the safety circuit release input is input.
This circuit does not work.

First, the absolute values of the force differential signal Fe and the velocity signal θ are εF, respectively.
The absolute value comparison circuits 21 and 22 determine whether or not the values are larger than e and εθ. The absolute value comparison circuits 21 and 22 output "1" when the absolute values of the signals are respectively larger than the thresholds to be compared, and output "φ" when they are small.

The outputs of the absolute value comparators 21 and 22 enter the and circuit 24 and further the circuit 2
The output of 4 becomes the input of the latch circuits 25 and 29. The latch circuit 29 is output to the speed command selection circuit. As shown in FIG. 3, when the output is “1”, the abnormal command is selected, and when the output is “φ”, the balanced operation command is selected as the motor rotation speed command. It That is, the absolute values of the force differential signal Fe and the velocity signal θ are
If both εFe and εθ are larger, an abnormal time command is output. The absolute value comparison circuit 23 determines whether the absolute value of the difference between the force signal Fe and the memory Wφ from the memory circuit is larger or smaller than εemg. The circuit 23 also outputs "1" when it is large and outputs "φ" when it is small.

The output of the circuit 23 and the output of the latch circuit 25 are input to the and circuit 26.

The absolute value comparison circuit 23 is a circuit for determining a shock or a sudden change in load. In the case of a shock, the absolute value of the difference between the force signal Fe and the stored value Wφ is momentarily large, but the T time is, for example, 2 seconds or more continuously. And there is nothing big. If the load changes suddenly, Tφ time,
For example, the absolute value does not decrease continuously for 0.5 seconds or longer.

The above time management is performed by the timers 27 and 28. Timer 27, 28
Details of the operation will be described below.

When the outputs of the latch circuit 25 and the absolute value circuit 23 are both “1”, a start signal is output from the and circuit 26 to the timer 28. The timer 28 is a timer for judging a sudden change in load, and outputs "1" from the out port unless the T time reset signal is input after the start signal is input.

In addition, the output is output to the or circuit 31, and the shock judgment timer
Output to 27 reset signal input ports. The timer 28 is reset when the output of the and circuit 26 is “φ”, the timer 27 times out, or when the safety circuit release input is input. On the other hand, the start signal of timer 27 is an
When the output of the d circuit 26 is “φ”, that is, the absolute value comparison circuit 23
Alternatively, it is output when one of the outputs of the latch circuit 25 is “φ”.

The timer 27 is a timer for releasing the sudden load change mode, and the time-up time is set to about 0.5 seconds.

According to the above configuration, when a shock is applied, the timer 27
Just to be in the load sudden change mode for the time set by, so that it automatically returns to the equilibrium operation mode afterwards.
On the other hand, when the load changes suddenly, it is fixed in the load sudden change mode and cannot be released until the safety circuit release input is input.
Can be operated.

(Effects of the Invention) According to the present invention, when a load is subjected to equilibrium operation at a predetermined speed or more and a sudden change load such as an impact is applied, a sudden movement of the load is reliably prevented, Work efficiency and work safety can be greatly improved by preventing the danger of jumping and dropping.

In addition, when a sudden load change occurs during balanced operation, it is judged whether it is a temporary sudden load or continuous sudden change load, and if it is a temporary sudden load, the balanced operation is continued as it is to improve operability. The work efficiency can be improved without affecting the safety of the work, and if the load changes continuously, sudden movement of the load can be reliably prevented and the danger of jumping or dropping of the load can be prevented. Can be greatly improved.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram showing an embodiment of the present invention, FIG. 2 is a configuration diagram showing the safety circuit and operation of the present invention, and FIG. Is. 21, 22, 23 …… Absolute value comparison circuit 24, 26 …… and circuit 25, 29 …… Latch circuit 27, 28 …… Timer 30, 31, 32 …… or circuit 33, 34 …… Inversion circuit

Claims (2)

[Claims] 1. An actuator for raising and lowering a load, a drive circuit for driving the actuator, a force detector for detecting the load, an acceleration detector for detecting the acceleration of the load, and a speed detector for detecting the speed of the actuator. , A position detector that detects the position of the actuator, and a speed commander that inputs a speed command, in a balanced cargo handling device, the differential value of the signal (dFe / dt)
And the signal (dθ / dt) from the speed detector, the absolute value of the differential signal (dFe / dt) of the force detector is larger than a certain threshold value ε (dFe / dt), and the speed detector When the absolute value of the signal (dθ / dt) from is larger than a predetermined threshold value ε (dθ / dt), (a) the equilibrium operation is temporarily stopped, and the signal θ from the position detector and the velocity signal (dθ / d
t) and the acceleration signal a are negatively fed back, or (b) once the signal Fe from the force detector in equilibrium operation
And the load memory value Wφ that stores this signal Fe for a predetermined time
A safety circuit for a balanced cargo handling apparatus, comprising control means for controlling a force negative feedback gain K, which is multiplied by the difference between and, to output the force negative feedback gain K smaller than during normal balanced operation. 2. An actuator for raising and lowering a load, a drive circuit for driving the actuator, a force detector for detecting the load, an acceleration detector for detecting the acceleration of the load, and a speed detector for detecting the speed of the actuator. , A position detector that detects the position of the actuator, and a speed commander that inputs a speed command, in a balanced cargo handling device, the differential value of the signal (dFe / dt)
And the signal (dθ / dt) from the speed detector, the absolute value of the differential signal (dFe / dt) of the force detector is larger than a certain threshold value ε (dFe / dt), and the speed detector When the absolute value of the signal (dθ / dt) from is larger than a predetermined threshold value ε (dθ / dt), the load storage value Wφ that stores the signal Fe from the force detector during equilibrium operation for a predetermined time , The absolute value of the difference from the signal Fe from the force detector is a predetermined threshold εem
If it is continuously smaller than g for a predetermined time T0 or more, it is judged to be a temporary sudden load and the normal force negative feedback gain K is output to continue equilibrium operation, and continuously larger for a predetermined time T0 or more. In this case, it is judged that the load is continuous and the balance operation is stopped, and the signal θ, speed signal (dθ / dt), and acceleration signal a from the position detector are negatively fed back, or the balance operation is performed. Control for controlling the force negative feedback gain K, which is obtained by multiplying the difference between the signal Fe from the force detector and the load memory value Wφ storing this signal Fe for a predetermined time, by outputting a smaller value than that during normal equilibrium operation. A safety circuit for a balanced cargo handling device, comprising a means.