KR102823050B1 - Charging gun insertion control system and method for automatic charging of electric vehicles - Google Patents

Abstract

The present invention relates to a charging gun insertion control system and method for automatic charging of electric vehicles.
A charging gun insertion control method for automatic charging of an electric vehicle according to the present invention comprises: (a) a step of sensing force data during a process of combining an electric vehicle charging gun and a charging port; (b) a step of setting a wiggle direction using the force data sensed in step (a); and (c) a step of determining a completion state of insertion of the electric vehicle charging gun and the charging port.

Description

{CHARGING GUN INSERTION CONTROL SYSTEM AND METHOD FOR AUTOMATIC CHARGING OF ELECTRIC VEHICLES}

The present invention relates to a charging gun insertion control system and method for automatic charging of electric vehicles.

According to the prior art, when a charging gun is attached to an electric vehicle charging port, alignment between the peg-holes is performed through a shaking motion without any information, so if the spring constant of the compliance control is not properly adjusted, there is a problem of causing breakage.

In addition, if the compliance control is very weak, there is a problem in that an external force is transmitted from the charging port, and conversely, a phenomenon in which the posture is greatly distorted occurs.

The present invention has been proposed to solve the above-mentioned problems, and its purpose is to provide a charging gun insertion control system and method that supports more robust coupling in actual situations by applying a smart wiggle motion that sets a wiggle direction using external force information obtained through a sensor.

The present invention relates to a charging gun insertion control system and method for automatic charging of electric vehicles.

A charging gun insertion control method for automatic charging of an electric vehicle according to the present invention comprises: (a) a step of sensing force data during a process of combining an electric vehicle charging gun and a charging port; (b) a step of setting a wiggle direction using the force data sensed in step (a); and (c) a step of determining a completion state of insertion of the electric vehicle charging gun and the charging port.

The above step (a) senses the force applied to the flange area using a six-axis force/torque sensor or a joint torque sensor.

In the above step (b), if the force data is used to monitor that a force other than the direction of travel is measured, the wiggle direction is set.

The step (c) above monitors whether the preset external force criteria and displacement criteria are met to determine the insertion completion status.

In the above step (c), if it is confirmed that a reaction within a preset range is detected against a force pushing the charging gun in the preset axial direction, it is determined that the external force criterion is satisfied.

The step (c) above includes: (c-1) a step of storing a robot base reference position, (c-2) a step of pushing the charging gun in a preset axis direction and checking a change in the robot base reference position, (c-3) a step of obtaining a robot base reference rotation matrix and its transpose matrix of the tool coordinate system, (c-4) a step of calculating a total displacement based on the tool coordinate system direction, and (c-5) a step of determining that the displacement criterion is satisfied when the total displacement is included within a preset range.

The charging gun insertion control system for automatic charging of an electric vehicle according to the present invention includes an input interface device for receiving force data acquired during a process of inserting a charging gun into a charging port, a memory storing a program for setting a wiggle direction using the force data, and a processor for executing the program, wherein the processor monitors whether a force other than a direction of movement of the charging gun is measured using the force data to set the wiggle direction.

The above input interface device receives the force data regarding the force applied to the flange area from a six-axis force/torque sensor or a joint torque sensor.

The above processor determines the insertion completion status of the charging gun based on whether preset external force criteria and displacement criteria are met.

The above processor determines that the external force criterion is met when it determines that a reaction within a preset range is detected against the force pushing the charging gun.

The above processor stores the robot base reference position, pushes the charging gun in a preset axis direction, checks the change in the robot base reference position, obtains the robot base reference rotation matrix and its transpose matrix of the tool coordinate system, calculates the total displacement based on the tool coordinate system direction, and determines that the displacement criterion is satisfied if the total displacement is included within a preset range.

According to the present invention, since the insertion of the charging port and the charging gun is deep and strong, it is possible for one robot to utilize multiple chargers while leaving only the charging gun connected, thereby making it possible to lower the unit cost of charging.

According to the present invention, in addition to the coupling for electric vehicle charging, there is an advantage that can be utilized for insertion control between two contact surfaces that are not aligned with each other, and an advantage that can be utilized for insertion control between two contact surfaces having geometric anisotropy.

The effects of the present invention are not limited to those mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the description below.

Figure 1 illustrates a smart wiggle control start situation according to an embodiment of the present invention.
Figure 2 illustrates a charging gun insertion control method for automatic charging of an electric vehicle according to an embodiment of the present invention.
Figure 3 illustrates the charging gun direction adjustment according to an embodiment of the present invention.
FIG. 4 is a block diagram illustrating a computer system for implementing a method according to an embodiment of the present invention.

The above-mentioned objects and other objects, advantages and features of the present invention, and methods for achieving them will become apparent with reference to the embodiments described below in detail together with the accompanying drawings.

However, the present invention is not limited to the embodiments disclosed below, but can be implemented in various different forms, and the following embodiments are merely provided to easily inform a person having ordinary skill in the art to which the present invention pertains of the purpose, structure, and effect of the invention, and the scope of the rights of the present invention is defined by the description of the claims.

Meanwhile, the terminology used in this specification is for the purpose of describing embodiments and is not intended to limit the present invention. In this specification, the singular also includes the plural unless specifically stated in the phrase. The terms "comprises" and/or "comprising" as used in the specification do not exclude the presence or addition of one or more other components, steps, operations, and/or elements to the mentioned components, steps, operations, and/or elements.

The technology of combining a charging gun and a charging port according to the prior art assumes that the location and attitude information of the charging port obtained from the sensor are accurate. However, in reality, due to the characteristics of the charging port (color, etc.) that make it difficult to obtain information using a vision sensor, it is difficult to accurately determine the attitude, and accordingly, there is a problem that the alignment of the charging port and the charging gun is difficult.

In view of this, in the field of research mainly on the peg-in-hole task of robots, the position search of the charging port through a spiral motion, that is, the alignment and insertion process through a wiggle motion are utilized. In the case of light objects, there is no major problem, but in the case of a large load, there is a problem that the problem of damage is accompanied because the movement is controlled in an inaccurate direction. To prevent this, if the compliance control is weakly applied, there is a problem that the robot arm cannot maintain its posture due to an external force and the combination fails.

That is, according to the prior art, due to the characteristics of the charging port being black in color and not clearly showing its features, there is a problem in that it is difficult to estimate the exact position and posture using the camera (vision sensor) of the robot arm, and even if a three-point contact is made, there is a high possibility that the charging port and the charging gun will not be aligned with each other. In addition, since the shape of the charging port is not isotropic on the contact plane, there is a high possibility that the alignment status will be a problem if it is isotropic.

The present invention has been proposed to solve the above-mentioned problems, and supports more robust coupling in real situations by applying a smart wiggle motion that sets the direction of the wiggle motion based on external force information obtained through a sensor.

The charging gun insertion control system for automatic charging of an electric vehicle according to an embodiment of the present invention includes a robot arm having a six-axis force/torque sensor mounted on a flange portion or a joint torque sensor mounted on a joint to measure (or calculate) a force applied to the flange portion. The charging port and the charging gun to be coupled complete position search and make three-point contact with each other. Since the robot can move while leaving only the charging gun behind without waiting while charging an electric vehicle, it is necessary to insert it sufficiently deep into the charging port.

Figure 1 illustrates a smart wiggle control start situation according to an embodiment of the present invention.

It shows that a normal force and a frictional force are generated at the point of contact between the charging gun and the charging port, and that the direction is incorrect with respect to the three-point contact state.

Figure 2 illustrates a charging gun insertion control method for automatic charging of an electric vehicle according to an embodiment of the present invention.

Step S201 performs a change to the tool coordinate flange in a three-point contact situation.

In step S202, compliance is set, and 0 is set for rotation.

At step S203, a command is sent to apply force in the forward direction, causing it to continue pushing.

At step S204, forces other than those in the forward direction are measured.

At step S205, if it is confirmed that an x-axis force is input, step S206 transmits an x-axis movement command.

At step S207, if it is confirmed that a y-axis force is input, step S208 transmits a y-axis movement command.

Step S209 checks whether sufficient insertion has occurred.

When sufficient insertion is confirmed at step S209, the bonding is terminated.

Figure 3 illustrates the charging gun direction adjustment according to an embodiment of the present invention.

According to an embodiment of the present invention, assuming a situation where 80 N is pushed in the z-axis direction, the incoming force and the moving direction based on the tool coordinate system are opposite to each other within the same axis. The x-axis and y-axis move in small units and monitor the change in force, moving in units of 5 mm and applying a maximum movement of 10 mm are possible.

Referring to FIG. 3, the blue arrow represents the force pushing the charging port (illustrated as port 303) with the charging gun (illustrated as tool body 301 and tool tip 302), which represents the force applied by the robot in the z-direction. Referring to FIG. 3, the red arrow represents the normal force due to the connection. Referring to FIG. 3, the green arrow represents the reaction force due to friction.

The force that the charging gun uses to push the charging port must be very large compared to the static frictional force, and control is only possible when the normal force is sufficiently large compared to the frictional force.

The normal force, shown by the red arrow, is separated into the force along the z-axis and perpendicular to it with respect to the charging gun.

When the force perpendicular to the z-axis exceeds the reference value, the flange part of the robot arm moves in the opposite direction to the force. At this time, the charging gun, whose compliance is completely released by the vertical force, changes its orientation.

The charging gun is continuously pushed in the z-axis direction of the tool coordinate system, so that insertion into the charging port is completed.

Below, insertion completion determination according to an embodiment of the present invention is described.

According to an embodiment of the present invention, insertion completion is determined based on the magnitude of an external force coming in the opposite direction to the tool travel direction and the displacement in the current tool travel direction compared to the initial position.

In relation to the external force criterion, assuming that the tool is fully engaged, the reaction in the direction of pushing the tool in the z-axis must be detected. For example, assuming that it is pushed by 80N, if it comes within the range of ±5N based on -80N, it is judged that the external force condition is satisfied.

).In relation to the displacement reference, the robot base reference position of the tool is saved just before starting the smart wiggle movement (initial position

).

).As you start pushing the tool along the z-axis, check the current position of the tool relative to the robot base at each moment (current position

).

Using forward kinematics, we obtain the rotation matrix of the robot base relative to the current tool coordinate system at each moment ( ), find the transpose of this matrix ( ).

Calculates the total displacement relative to the current tool coordinate system direction ( ).

If the z-axis component of this vector is within 30 mm to 35 mm based on the CCS type 1 charging port, it is judged as a sufficiently inserted displacement criterion.

According to an embodiment of the present invention, insertion is determined to be complete when both the external force criterion and the displacement criterion described above are satisfied.

The control method according to the embodiment of the present invention can be applied to a test laboratory environment utilizing tools requiring strong bonding force. In the case of high-load tools, the tool changer shape is anisotropic and the contact surface is likely to be uneven. According to the embodiment of the present invention, it is possible to ensure the bonding success rate of multiple tools and to compensate for errors in position and posture.

FIG. 4 is a block diagram illustrating a computer system for implementing a method according to an embodiment of the present invention.

Referring to FIG. 4, the computer system (1300) may include at least one of a processor (1313), a memory (1330), an input interface device (1350), an output interface device (1360), and a storage device (1340) communicating via a bus (1370). The computer system (1300) may also include a communication device (1320) coupled to a network. The processor (1310) may be a central processing unit (CPU), or a semiconductor device that executes instructions stored in the memory (1330) or the storage device (1340). The memory (1330) and the storage device (1340) may include various forms of volatile or nonvolatile storage media. For example, the memory may include a read only memory (ROM) and a random access memory (RAM). In embodiments of the present disclosure, the memory may be located internally or externally to the processor, and the memory may be connected to the processor via various known means. Memory is a variety of volatile or nonvolatile storage media, for example, memory may include read-only memory (ROM) or random access memory (RAM).

A charging gun insertion control system for automatic charging of an electric vehicle according to an embodiment of the present invention includes an input interface device (1360) for receiving force data acquired during a charging port insertion process of a charging gun, a memory (1330) storing a program for setting a wiggle direction using the force data, and a processor (1310) for executing the program, wherein the processor (1310) monitors whether a force other than a direction of travel of the charging gun is measured using the force data to set the wiggle direction.

The input interface device (1360) receives force data on the force applied to the flange area from a six-axis force/torque sensor or a joint torque sensor.

The processor (1310) determines whether the insertion of the charging gun is complete based on whether preset external force criteria and displacement criteria are met.

When the processor (1310) determines that a reaction within a preset range is detected against the force applied to the charging gun, it determines that the external force criterion is met.

The processor (1310) stores the robot base reference position, pushes the charging gun in the preset axis direction, checks the change in the robot base reference position, obtains the robot base reference rotation matrix and its transpose matrix of the tool coordinate system, calculates the total displacement based on the tool coordinate system direction, and determines that the displacement criterion is satisfied if the total displacement is included within the preset range.

Accordingly, embodiments of the present invention may be implemented as a computer-implemented method or as a non-transitory computer-readable medium having computer-executable instructions stored thereon. In one embodiment, the computer-readable instructions, when executed by a processor, may perform a method according to at least one aspect of the present disclosure.

The communication device (1320) can transmit or receive wired or wireless signals.

In addition, the method according to the embodiment of the present invention may be implemented in the form of program commands that can be executed through various computer means and recorded in a computer-readable medium.

The above computer-readable medium may include program commands, data files, data structures, etc., alone or in combination. The program commands recorded on the computer-readable medium may be specially designed and configured for the embodiments of the present invention, or may be known and usable to those skilled in the art of computer software. The computer-readable recording medium may include a hardware device configured to store and execute the program commands. For example, the computer-readable recording medium may be a magnetic media such as a hard disk, a floppy disk, and a magnetic tape, an optical media such as a CD-ROM, a DVD, a magneto-optical media such as a floptical disk, a ROM, a RAM, a flash memory, etc. The program commands may include not only machine language codes generated by a compiler, but also high-level language codes that can be executed by a computer through an interpreter, etc.

Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements made by those skilled in the art using the basic concept of the present invention defined in the following claims also fall within the scope of the present invention.

Claims (11)

In a charging gun insertion control method for automatic charging of an electric vehicle, performed by a charging gun insertion control system for automatic charging of an electric vehicle,
(a) a step of sensing force data during the process of combining an electric vehicle charging gun and a charging port;
(b) a step of setting the wiggle direction using the force data sensed in step (a); and
(c) a step of monitoring whether the preset external force criteria and displacement criteria are met and determining the completion status of insertion of the electric vehicle charging gun and charging port;
Step (c) above,
(c-1) Step of saving the robot base reference position;
(c-2) A step of pushing the charging gun in the preset axis direction and checking the change in the reference position of the robot base;
(c-3) A step of obtaining a robot base-based rotation matrix and its transpose matrix in the tool coordinate system;
(c-4) a step of calculating the total displacement based on the tool coordinate system direction; and
(c-5) Including a step of determining that the displacement criterion is met when the total displacement is within the preset range.
A charging gun insertion control method for automatic charging of an electric vehicle.
In the first paragraph,
The above step (a) senses the force applied to the flange area using a 6-axis force/torque sensor or a joint torque sensor.
A charging gun insertion control method for automatic charging of an electric vehicle.
In the first paragraph,
In the above step (b), if the force data is used to monitor that a force other than the direction of travel is measured, the wiggle direction is set.
A charging gun insertion control method for automatic charging of an electric vehicle.
delete In the first paragraph,
The step (c) above is judged to satisfy the external force criterion when it is confirmed that a reaction within a preset range is detected against a force pushing the charging gun in the preset axial direction.
A charging gun insertion control method for automatic charging of an electric vehicle.
delete An input interface device for receiving force data obtained during the process of inserting a charging port of a charging gun;
A memory storing a program for setting a wiggle direction using the above force data; and
comprising a processor that executes the above program,
The processor monitors whether a force other than the direction of travel of the charging gun is measured using the force data to set the wiggle direction,
The above processor determines the insertion completion status of the charging gun based on whether preset external force criteria and displacement criteria are satisfied, stores the robot base reference position, pushes the charging gun in the preset axial direction, checks the change in the robot base reference position, obtains the robot base reference rotation matrix and its transpose matrix of the tool coordinate system, calculates the total displacement based on the tool coordinate system direction, and determines that the displacement criteria are satisfied if the total displacement is included within the preset range.
A charging gun insertion control system for automatic charging of electric vehicles.
In Article 7,
The above input interface device receives the force data on the force received by the flange area from a 6-axis force/torque sensor or a joint torque sensor.
A charging gun insertion control system for automatic charging of electric vehicles.
delete In Article 7,
The above processor determines that the external force criterion is met when it determines that a reaction within a preset range is detected against the force pushing the charging gun.
A charging gun insertion control system for automatic charging of electric vehicles. delete