Human detection coordinate output device

Abstract

To provide a coordinate output device for person detection, which can surely prevent collision of a crane-suspended load with a person using a general-purpose PC for a PC constituting a person detection device.SOLUTION: A general-purpose PC 16 and a PLC 09 are respectively provided on a crane crab and a girder. Collision of a crane-suspended load with a person is prevented by calculating coordinates of a person detected by cameras 18, 20 and a distance from a crane hook. The general-purpose PC 16 calculates the coordinates of the person detected by the cameras 18, 20, notifies the PLC 09 of coordinates of a preset number of people including the calculated coordinates of the person and the number of people detected by the cameras 18, 20. The PLC 09 calculates the distance of the person detected by the cameras 18, 20 from the crane hook on the basis of the coordinates of the set number of people notified from the general-purpose PC 16 and the number of people detected by the cameras 18, 20.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a coordinate output device for human detection used in a safety confirmation device for preventing collisions between workers (persons) and the suspended load of a crane in a crane work area.

Background Art

[0002] Conventionally, as a safety confirmation device for preventing collisions between workers and the suspended load of a crane in a crane work area, a camera is used to photograph the area around the crane from above the crane, and a recognition unit that recognizes the helmets worn by the workers sets a danger area and displays it on a monitor for safety confirmation (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document Ⅰ

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in this type of safety confirmation device, a personal computer (PC) and a programmable logic controller (PLC) are used to calculate the coordinates of a person detected by a camera and the distance from the hook of the crane, so as to prevent the suspended load of the crane from colliding with a person. Specifically, as shown in the sequence diagram of the PC and PLC in Figure 4, the PC, which constitutes the human detection device, shifts the image according to the speed and direction of movement of the crane, and processes the image of the person captured by the camera to calculate the coordinates of the person and the distance from the crane hook. The calculated results are then notified to the PLC via TCP / IP packet communication. Based on the information notified from the PC, the PLC determines whether the distance to the person (his helmet detected by the camera), taking into account the suspended load (size of the cargo), is dangerous or not, and controls (stops) the crane. Thus, if the calculation of the coordinates of people captured by the camera and the distance from the crane hook is performed using a general-purpose PC in the PC that constitutes the human detection device, then, for example, if there are many people to be detected, the calculation of the coordinates of the people and the distance from the crane hook may take time, potentially delaying safety checks. Furthermore, even when the number of people being detected is small, with a general-purpose PC, the communication interval between notifications from the PC to the PLC (the time from the end of one communication to the start of the next) becomes shorter, increasing the number of communications. In such cases, the PLC temporarily pauses data reception before the TCP / IP packet receiving area on the PLC side overflows, resulting in retries to the communication from the PC to the PLC. This can cause delays in notifications from the PC to the PLC, potentially making it impossible to reliably perform safety checks. This is because when TCP / IP packet communication is performed between a PC and a PLC, the connection between the PC and the PLC is opened and closed, but a wait time (waiting time) is required between closing the connection and reopening it.

[0005] To resolve the above problem, one could consider using a PC with high specifications and a real-time OS that allows specifying the processing time so that a predetermined wait time (waiting time) is secured between closing and reopening communication between the PC and PLC, regardless of the number of people being detected. However, this would result in higher costs compared to general-purpose PCs.

[0006] Furthermore, the human detection coordinate output device could be easily applied to existing crane control systems that include safety confirmation devices. By incorporating the human detection coordinate output device, it was necessary to enable the PLC to reliably determine whether the crane was ultimately safe to operate.

[0007] In view of the problems that arise when a general-purpose PC is used as the PC constituting the above-mentioned person detection device, the present invention aims to provide a person detection coordinate output device that can reliably prevent a crane's suspended load from colliding with a person by using a general-purpose PC as the PC constituting the person detection device. [Means for solving the problem]

[0008] To achieve the above objective, the present invention provides a person detection coordinate output device that includes a general-purpose PC on the crane's cradle and a PLC on the girder, and prevents the crane's suspended load from colliding with a person by calculating the coordinates of a person detected by a camera and the distance from the crane's hook. The general-purpose PC calculates the coordinates of a person detected by the camera, notifies the PLC of the coordinates of a predetermined number of people including the calculated coordinates of the person, and the number of people detected by the camera. The PLC then calculates the distance from the crane's hook of the person detected by the camera based on the coordinates of the predetermined number of people notified by the general-purpose PC and the number of people detected by the camera.

[0009] In this case, the PLC can extract only the coordinates of the number of people detected by the camera from the coordinates of the set number of people notified from the general-purpose PC, and calculate the distance of the people detected by the camera from the crane hook. [Effects of the Invention]

[0010] The present invention provides a person detection coordinate output device that, when incorporated into an existing crane control system including a safety confirmation device, can reliably prevent the crane's suspended load from colliding with a person by using a general-purpose PC as the PC constituting the person detection device. [Brief explanation of the drawing]

[0011] [Figure 1] This is a system configuration diagram of a safety confirmation device to which the human detection coordinate output device of the present invention is applied. [Figure 2] These are sequence diagrams for general-purpose PCs and PLCs. [Figure 3] This is a timing chart for general-purpose PCs and PLCs. [Figure 4] This is a sequence diagram for a PC and a PLC. [Modes for carrying out the invention]

[0012] Hereinafter, embodiments of the coordinate output device for human detection according to the present invention will be described based on the drawings.

[0013] Figures 1 to 3 show an embodiment of the coordinate output device for human detection according to the present invention.

[0014] Figure 1 shows an example of a system configuration for a safety confirmation device that applies the person detection coordinate output device of the present invention to prevent accidents such as collisions between workers (people) and loads suspended by cranes in a crane work area. In Figure 1, the crane is equipped with a drive mechanism consisting of a main hoisting motor 01, a main hoisting inverter 02, an auxiliary hoisting motor 03, an auxiliary hoisting inverter 04, a traverse motor 05, a traverse inverter 06, a travel motor 07, and a travel inverter 08 on the crane; a PLC control panel 09 (hereinafter referred to as "PLC"), a human detection status indicator light 10, a human detection number indicator 11, and a wireless receiver 12 on the girder; and a load cell 13 for load detection, an upper limit switch 14, a voice loudspeaker 15, and a personal computer 16 (hereinafter referred to as "general-purpose PC") on the cradle. The system is equipped with a touch panel 17, a human detection camera 18 (human detection camera 1 (human detection camera unit 1)), a human detection illuminator 19 (human detection illuminator 1 (human detection camera unit 1)) consisting of an infrared illuminator, a human detection camera 20 (human detection camera 2 (human detection camera unit 2)), a human detection illuminator 21 (human detection illuminator 2 (human detection camera unit 2)) consisting of an infrared illuminator, and a wireless transmitter (wireless operator) 22.

[0015] The human detection coordinate output device of the present invention, as shown in the sequence diagram of the general-purpose PC and PLC in Figure 2, is equipped with a general-purpose PC 16 on the crane's cradle and a PLC 09 on the girder, respectively, and prevents the crane's suspended load from colliding with a person by calculating the coordinates of a person detected by cameras 18 and 20 and the distance from the crane's hook. The general-purpose PC 16 calculates the coordinates of a person detected by cameras 18 and 20, and notifies the PLC 09 of the coordinates of a predetermined number of people (not particularly limited, but for example, 10 to 50 people; in this embodiment, 20 people) including the calculated coordinates of the person, and the number of people detected by cameras 18 and 20. Based on the coordinates of the predetermined number of people notified by the general-purpose PC 16 and the number of people detected by cameras 18 and 20, the PLC 09 calculates the distance from the crane's hook to the person detected by cameras 18 and 20, determines whether the distance to the person (helmet detected by the camera) taking into account the suspended load (cargo size) is dangerous, and controls (stops) the crane.

[0016] In this person detection coordinate output device, the suspended load (package size) is registered in advance as a maximum standard size (length, width, height) via the touch panel 17, and the shape of the suspended load is defined as a circumscribed circle with a radius from the center of the suspended load to the point furthest away.

[0017] Also, human detection is to detect a retroreflective mark attached to the helmet. Specifically, the ON / OFF images of the human detection projectors 19 and 21 composed of infrared projectors are captured by the human detection cameras 18 and 20 and imported into the general-purpose PC 16. The imported images are centered on the hook in use with the center coordinates (0, 0), and the images are shifted according to the crane moving direction and speed to perform differential processing on the ON / OFF images of the infrared projectors, thereby calculating the coordinates (X, Y) of the detected person.

[0018] Data transmission and reception between the general-purpose PC 16 and the PLC 09 are each performed by a message by providing transmission data, a transmission flag, and a reception flag. Specifically, as shown in the timing chart of the general-purpose PC and the PLC in FIG. 3, when transmitting data on the crane moving direction, speed, and main / auxiliary winding selection to the general-purpose PC 16 at the timing on the PLC 09 side, when the setting of the data is completed in the transmission area on the PLC 09 side, the transmission flag on the PLC 09 side is turned ON. When the general-purpose PC 16 confirms that the transmission flag on the PLC 09 side is ON, the general-purpose PC 16 starts receiving the transmission data on the PLC 09 side. When the general-purpose PC 16 completes receiving the transmission data, the reception flag is turned ON. When the PLC 09 confirms that the reception flag on the general-purpose PC 16 side is ON, the PLC 09 resets the data in the transmission area on the PLC 09 side and turns OFF the transmission flag. Finally, the general-purpose PC 16 confirms that the transmission flag on the PLC 09 side is OFF and turns OFF the reception flag on the general-purpose PC 16 side to end one message.

[0019] For human detection, the coordinates determined as helmets by the human detection cameras 18 and 20 are each subjected to tracking processing according to the crane moving direction and speed, and the recognition coordinates of the human detection cameras 18 and 20 are subjected to coordinate transformation in the real space based on the hook. The coordinates of the human detection cameras 18 and 20 with close results after coordinate transformation are grouped together, and integration is performed with the hook as the center coordinates (0, 0). The integrated result is used to calculate the coordinates from the hook center to the helmet, and the data is set from the head address in the order of detection within the camera field of view. Specifically The coordinate information search order is as follows: the XY coordinate plane is classified into four quadrants, and the search is performed in the following order: (0,0), (+X,0), first quadrant (+X,+Y), (0,+Y), second quadrant (-X,+Y), (-X,0), third quadrant (-X,-Y), (-Y,0), and fourth quadrant (+X,-Y). The data is then set from the first address in the order in which it is detected.

[0020] When transmitting the detected XY coordinates and the number of people detected from the general-purpose PC 16 to the PLC 09, as shown in the timing chart for the general-purpose PC and PLC in Figure 3, the transmission flag on the general-purpose PC 16 is turned ON once the data has been set in the transmission area on the general-purpose PC 16 side. When PLC09 confirms that the transmit flag on the general-purpose PC16 is ON, it begins receiving the data transmitted from the general-purpose PC16. Once PLC09 has finished receiving the transmitted data, it turns the receive flag ON. When the general-purpose PC16 confirms that the receive flag on the PLC09 side is ON, it resets the data in the transmit area on the general-purpose PC16 side and turns the transmit flag OFF. Finally, PLC09 confirms that the transmit flag on the general-purpose PC16 side is OFF, and then turns OFF the receive flag on the PLC09 side to complete one message.

[0021] As shown in the example in Figure 4, when the number of people detected is small, if coordinate calculation, person notification, and distance calculation are performed, the communication interval between notifications from the general-purpose PC 16 to the PLC 09 becomes shorter than the manufacturer's recommended time, such as 500ms. If the number of communications increases, data reception is temporarily paused before the TCP / IP packet receiving area on the PLC 09 side overflows. In addition, if the transmit flag on the general-purpose PC 16 side is ON and a certain period of time (1 second) has passed, but the receive flag on the PLC 09 side is not ON, a communication error is detected and the system is forcibly terminated. Therefore, because it may not be possible to reliably notify the PLC09 of all information regarding human detection from the general-purpose PC 16, as shown in the embodiment in Figure 4, the general-purpose PC 16 calculates the coordinates (X,Y) of the people detected by cameras 18 and 20, and notifies the PLC09 of the coordinates (X,Y) of a predetermined number of people (20 people), including the calculated coordinates (X,Y), as well as the number of people detected by cameras 18 and 20. This ensures that the communication interval for notifications from the general-purpose PC 16 to the PLC09 is 500ms or longer than the manufacturer's recommended time. Here, the coordinates (X,Y) of people other than those detected by cameras 18 and 20 are written as, for example, (0,0).

[0022] On the PLC09 side, from the coordinate information (X, Y) of the set number of people (for 20 people) sent from the general-purpose PC16, information for only the number of people notified, that is, information for only the number of people set out in the order they were detected, starting from the first address, is extracted, and the distance is calculated in order from the person closest to the hook ((X 2 +Y 2 ) 1 / 2 ) This is because the coordinates (X,Y) of people other than those detected by cameras 18 and 20 are written as (0,0), and it is necessary to distinguish them from the coordinates (0,0) closest to the hook. Therefore, the number of people detected is notified, and only the information for the number of detected people is extracted. Next, the distance from the circumscribed circle, with the radius being the point furthest from the center of the suspended load, to the person (helmet) is calculated. This is then compared to the distance from the hook to the person, taking the load size into account, to determine if it falls within the range where the crane should be decelerated or stopped. Finally, a decision is made to decelerate or stop the output frequency of the traverse inverter 06 and / or the travel inverter 08.

[0023] If PLC09 determines that it is necessary to stop the crane, it checks the current rope length and the current crane speed command, substitutes the values ​​into the simulation formula for preventing swaying if the crane were stopped from the current state, outputs the simulation results to the analog command (frequency) of the traverse inverter 06 and / or travel inverter 08, and controls the frequency of the traverse inverter 06 and / or travel inverter 08 in accordance with the simulation results so that the suspended load does not sway. The rotational speed of motor 05 and / or travel motor 07 is controlled so that if the distance from the hook to the person falls within the stopping range, the brakes are applied.

[0024] The person detection coordinate output device of the present invention has been described above based on its embodiments. However, the present invention is not limited to the configuration described in the above embodiments, and its configuration can be modified as appropriate without departing from the spirit of the invention. [Industrial applicability]

[0025] The human detection coordinate output device of the present invention can prevent collisions between workers and crane loads in crane work areas with a simple equipment configuration using a general-purpose PC, and can therefore be suitably used in overhead crane applications as well as in applications such as construction machinery that uses cranes. [Explanation of symbols]

[0026] 01 Main winding motor 02 Main winding inverter 03 Auxiliary winding motor 04 Auxiliary Winding Inverter 05 Traverse Motor 06 Traverse Inverter 07 Driving motor 08 Driving Inverter 09 PLC control panel (PLC) 10 people detected status indicator lights 11-person detection display 12 Wireless receiver 13 Load Cells 14 Upper limit switch 15. Loudspeaker 16. Personal computer (general-purpose PC) 17 Touch panel 18-person detection camera 1 19 Floodlight for person detection 1 20-person detection camera 2 21 Floodlights for Human Detection 22 Wireless Transmitter (Wireless Controller)

Claims

1. In a person detection coordinate output device that prevents the crane's suspended load from colliding with a person by calculating the coordinates of a person detected by a camera and the distance from the crane's hook, a general-purpose PC is installed on the crane's traction board and a PLC is installed on the girder, respectively. The general-purpose PC calculates the coordinates of the person detected by the camera, and notifies the PLC of the coordinates of a predetermined number of people, including the calculated coordinates of the person, and the number of people detected by the camera. The PLC calculates the distance from the crane hook to each person detected by the camera, based on the coordinates of the specified number of people notified from the general-purpose PC and the number of people detected by the camera. A coordinate output device for human detection, characterized by the following features.

2. The PLC extracts only the coordinates of the people detected by the camera from the coordinates of the set number of people notified from the general-purpose PC, and calculates the distance of the people detected by the camera from the crane hook. The person detection coordinate output device according to feature 1.

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