Robot control system

Provided is a robot control system and a method thereof. The robot control system includes: a mobile robot comprising at least one camera; and a controller, wherein the controller is configured to transmit, to the mobile robot, a signal for adjusting a resolution of a next image to be transmitted from the at least one camera to the controller, based on a data transmission rate of a current image captured by the at least one camera and output to the controller, and wherein the mobile robot is configured to adjust the resolution of the next image, based on the signal for adjusting the resolution of the next image.

CROSS-REFERENCE TO THE RELATED APPLICATION

This application claims priority from Korean Patent Application No. 10-2014-0086157, filed on Jul. 9, 2014, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference.

BACKGROUND

Apparatuses and methods consistent with exemplary embodiments relate to a robot control system, and more particularly, to a robot control system that transmits live-view moving picture data from a mobile robot to a control device of a remote control center, and outputs the real-time moving picture data to a display device through the control device.

2. Description of the Related Art

A typical robot control system includes a mobile robot and a control device that is included in a remote control center.

The mobile robot transmits live-view moving picture data to the controller of the remote control center through wireless communication therewith.

The control device outputs the live-view moving picture data to a display device through wireless communication with the mobile robot. In addition, according to a drive signal output from a user input device, the controller transmits a remote control signal to the mobile robot.

In detail, the mobile robot has two modes of operation; one is an automatic operation mode, and the other is a remote control operation mode.

In the case of the remote control operation mode, the mobile robot is remotely controlled by a user input in the remote control center. Here, cameras for capturing images of surroundings thereof are attached to the mobile robot such that a controller of the mobile robot transmits live-view moving picture data obtained by the cameras to the controller of the remote control center. Accordingly, the controller of the remote control center a display device to display the live-view moving pictures representing the surroundings of the mobile robot. Meanwhile, a user manipulates the user input module while watching the moving pictures representing the surroundings of the mobile robot. The controller of the remote control center generates a remote control signal in response to the drive signal output from the user input device, and such a remote control signal is transmitted to the mobile robot through an antenna of the remote control center. Accordingly, the mobile robot moves in response to the transmitted remote control signal.

In regard to the transmission of the live-view moving picture data from the mobile robot to the controller of the remote control center, a transmission rate of the live-view moving picture data may suddenly change in at least one channel according to an ambient environment. The term ‘an ambient environment’ used herein refers to an ambient luminance, a subject to be captured by a camera, and a pattern of the subject to be captured.

In the case of a sudden rise in the transmission rate of the live-view moving picture data, due to limitations in transmission capacity, at least some of the live-view moving picture data may be lost during the transmission. Accordingly, the live-view moving picture data being displayed on the display device included in the remote control center may also become distorted. That is, problems that may prevent a user from smoothly controlling the mobile robot may arise.

Such problems in the related art are addressed by the inventors to derive the present inventive concept. Thus, these problems may not be simply referred to as information which was known to the general public before the application of the present inventive concept.

SUMMARY

One or more exemplary embodiments provide a robot control system that allows a user smoothly control a mobile robot by eliminating distortion of image such as live-view moving picture data being displayed on a display device included in a remote control center.

According to one or more exemplary embodiments, there is provided a robot control system which may include a mobile robot and a controller.

The controller may transmit, to the mobile robot, a signal for adjusting a resolution of a next image to be transmitted from the at least one camera to the controller, based on a data transmission rate of a current image captured by the at least one camera and output to the controller.

The mobile robot may adjust the resolution of the next image, based on the signal for adjusting the resolution of the next image.

The resolution of the next image may be adjusted to be inversely proportional to the data transmission rate of the current image. The at least one camera may include a plurality of cameras configured to capture a plurality of current images and output the captured current images to the controller through a plurality of channels, respectively, wherein each of the current images has an importance degree for each of the plurality of channels, and wherein the resolution of the next image is adjusted based on the importance degree for each of the channels. The resolution of the next image for each of the channels may be adjusted to be inversely proportional to the data transmission rate of the current image for each of the channels.

Thus, even in the case of a sudden rise in the data transmission rate of the current image, image data loss may be prevented during the transmission. Accordingly, distortion of an image being displayed on a display included in a remote control center may be also prevented. That is, a user may smoothly control the mobile robot.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

The descriptions and attached drawings for illustrating the exemplary embodiments are referred to in order to gain a sufficient understanding, the merits thereof, and the objectives accomplished by the implementation. In the description, certain detailed explanations of the related art are omitted when it is deemed that they may be obvious to those of ordinary skill in the art.

FIG. 1is a diagram illustrating a robot control system1according to an exemplary embodiment of the present inventive concept.FIG. 2is a diagram showing a main configuration of a mobile robot12ofFIG. 1.

Referring toFIGS. 1 and 2, the robot control system1includes a user input module112, a controller113, and a mobile robot12according to an exemplary embodiment.

The user input module112included in a remote control center11generates a drive signal according to a user input. The user input module112includes a steering module, an accelerator, a brake and a gear-shifting module. That is, the drive signal may be a signal for steering, accelerating, breaking and gear-shifting control.

The controller113, e.g., a control computer, included in the remote control center11generates a remote control signal in response to the drive signal output from the user input module112.

Then, the mobile robot12moves according to the remote control signal output from the controller113.

In detail, cameras123for capturing images of surroundings of the mobile robot12are attached to the mobile robot12, and a controller201of the mobile robot12transmits live-view moving picture data obtained from the cameras123to the controller113of the remote control center11through a wireless communication interface206and an antenna124.

The controller113of the remote control center11processes signals of the live-view moving picture data output from the antenna114and displays the moving pictures representing the surroundings of the mobile robot12on a display115based on the processed signals. Accordingly, a user manipulates the user input module112while watching the moving pictures representing the surroundings of the mobile robot12being displayed on the display115.

The controller113of the remote control center11generates a remote control signal in response to the drive signal output from the user input module112. The generated remote control signal is transmitted wirelessly to the mobile robot12through an antenna114of the remote control center.

Then, the mobile robot12moves according to the received remote control signal. That is, the controller201of the mobile robot12is configured to control an operation of a track drive module203according to the remote control signal received from the antenna124and the wireless communication interface206of the mobile robot.

The track drive module203is configured to drive a track mechanism using, for example, a steering module, an accelerator, a brake and a gear-shifting module, according to the drive control signal output from the controller201. That is, the track control signals output from the controller201and input to the track drive module203may include control signals for steering, accelerating, breaking and gear-shifting. Here, the steering module, the accelerator, the brake and the gear-shifting module of the track driver module203may correspond to the steering module, the accelerator, the brake and the gear-shifting module of the user input module112included in the remote control center11in their respective functions.

In an exemplary embodiment, a plurality of sensors121for detecting a position of an object are attached to the mobile robot12, and the controller201of the mobile robot12creates a route along which the mobile robot12may drive in accordance with the information about the position of the object detected by the sensors121, e.g., laser sensors. In addition, the controller201of the mobile robot creates a driving guidance map during a driving mode, in accordance with the information about the position of the object detected by the sensors121. The term “a driving guidance map” used herein refers to a cost map such as “Grid-based Perception Cost map”. The cost map is configured to set an object area first, and then, set a remaining area as an available driving area.

In the robot control system1, the controller113of the remote control center11transmits signals for adjusting a resolution of an image, e.g., a live-view moving picture, to the mobile robots in accordance with a transmission rate of image data output from the mobile robot12. Here, the image of which the resolution is adjusted may be an image to be transmitted from the mobile robot12to the remote control center11at a next time unit, and the image data of which the transmission rate is measured may be that of an image captured by the cameras123of the mobile robot12and transmitted to remote control center11at a current time unit. Also, the image of which the resolution is adjusted and the transmission rate is measured may not be limited to a moving picture or moving image, and instead, may cover a still image.

The controller201of the mobile robot12adjusts, in accordance with the signals for adjusting the resolution of the image output from the controller113, the resolution of the live-view moving picture data to be transmitted to the controller113.

Here, the resolution of the live-view moving picture data to be transmitted to the controller113is set to be inversely proportional to a current transmission rate.

In addition, the live-view moving picture data is configured to have an importance degree for each of a plurality of channels included in the robot control system. For example, among video channels of the cameras123attached to the mobile robot12, a front camera has the highest importance degree, a rear camera has the second highest importance degree, a leftward camera has the third highest importance degree, and a rightward camera has the fourth highest importance degree. Accordingly, the resolution of the live-view moving picture data is set according to the importance degree for each of the channels (seeFIG. 7).

FIG. 3is a flowchart for explaining operation steps of the controller113of the remote control center11ofFIG. 1. Referring toFIGS. 1 to 3, the operation steps of the controller113of the remote control center may be explained as follows. That is, the controller113of the remote control center outputs the live-view moving picture data on the display115, the live-view moving picture data being output from the controller201of the mobile robot12, to perform the following operation.

The controller113of the remote control center11is configured to measure a transmission rate of the live-view moving picture data output from the mobile robot12for each of the channels (step S301).

Next, the controller113of the remote control center11transmits, in accordance with the transmission rate measured for each of the channels, a signal for adjusting a resolution to the mobile robot12(step S303).

Meanwhile, the controller113of the remote control center11determines whether any drive signals have been output from the user input module112(step S305).

In the step S305, if drive signals have been output from the user input module112, the controller113of the remote control center11transmits a remote control signal to the mobile robot12in response to the drive signals (step S307).

The steps S301to S307are repeatedly carried out until an end signal is generated (step S309).

FIG. 4is a flowchart for explaining operation steps of the controller201of the mobile robot12. Referring toFIGS. 1, 2 and 4, the operation steps of the controller201of the mobile robot12may be explained as follows.

The controller201of the mobile robot12transmits the live-view moving picture data to the controller113of the remote control center11, the live-view moving picture data being obtained by the cameras123that move according to the remote control signals output from the controller113of the remote control center11(step S401).

In addition, when the signal for resolution adjustment output from the controller113of the remote control center11is received (step S403), the controller201of the mobile robot12adjusts, in accordance with the received signal for resolution adjustment, a resolution of the live-view moving picture data to be transmitted to the controller113of the remote control center11(step S405).

The steps S401to S405are repeatedly carried out until an end signal is generated (step S407).

Referring to the operations illustrated inFIGS. 3 and 4, in regard to the transmission of the live-view moving picture data from the mobile robot12to the controller113, the resolution of the moving picture data to be transmitted may be automatically adjusted according to the current transmission rate. For example, the resolution of moving picture data to be transmitted may be automatically adjusted inversely proportional to the current transmission rate.

In this regard, even in the case of a sudden rise in the transmission rate of the live-view moving picture data in accordance with the images being captured, omission of the data that may occur due to limitations in transmission capacity during the transmission may be prevented. Accordingly, distortion of the live-view moving picture data being displayed on the display115of the remote control center11may be also prevented. That is, a user may smoothly control the mobile robot12.

FIG. 5is a graph showing a transmission rate which is associated with live-view moving picture data of one channel according to time and obtained by repetitively performing step S301ofFIG. 3.

Referring toFIGS. 1, 2 and 5, in regard to the transmission of the live-view moving picture data from the mobile robot12to the control device113of the remote control center11, it is confirmed that the transmission rate associated with one channel may suddenly change in accordance to an ambient environment. Here, the term ‘an ambient environment’ used herein refers to an ambient luminance, a subject, and a pattern of the subject to be imaged. For example, the measured transmission rate shows sudden changes during a period of 1658 to 1661 seconds and a period of 1669 to 1671 seconds.

In the case of such a sudden rise in the transmission rate as measured during a period of 1658 to 1659 seconds, a problem in which data is lost may occur due to limitations in transmission capacity. Accordingly, the moving pictures in live-view displayed on the display115may become distorted. That is, problems that may prevent a user from smoothly controlling the mobile robot may arise.

FIG. 6shows an example of a look-up table (LUT) used for performing step S303inFIG. 3.

Referring toFIG. 6, the resolution of the live-view moving picture data to be transmitted is set to be inversely proportional to a current transmission rate.

In an exemplary embodiment ofFIG. 6, the live-view moving picture data is not configured according to the importance degree for each of the channels. For example, among video channels of the cameras123attached to the mobile robot12, the importance degrees of the front camera channel, the rear camera channel, the leftward camera channel and the rightward camera channel are the same as one another.

Accordingly, the live-view moving picture data for each of the channels is configured to have only one resolution based on the transmission rate of any one of the camera channels (Mbps: Mega-bits per second).

FIG. 7shows another example of an LUT used for performing step S303inFIG. 3.

Referring toFIG. 7, the resolution of the live-view moving picture data to be transmitted is set to be inversely proportional to a current transmission rate.

In an exemplary embodiment ofFIG. 7, the live-view moving picture data is configured according to the importance degree for each of the channels. For example, among video channels of the cameras123attached to the mobile robot12, the front camera channel (first channel) has the highest importance degree, the rear camera channel (second channel) has the second highest importance degree, the leftward camera channel (third channel) has the third highest importance degree, and the rightward camera channel (fourth channel) has the fourth highest importance degree.

Accordingly, the live-view moving picture data for each of the channels is configured to have a different resolution according to the different importance degree. That is, the resolution of the live-view moving picture data channel is set differently for each of the channels based on the transmission rate of any one of the camera channels (Mbps: Mega-bits per second).

In other words, the resolution of the live-view moving picture data for each of the channels is inversely proportional to the transmission rate of the live-view moving picture data for each of the channels, and is proportional to the importance degree for each of the channels.

As described above, the robot control system may automatically adjust the resolution of the live-view moving picture data when transmitting the data from the mobile robot to the control device, in accordance with the current transmission rates. For example, the resolution of the live-view moving picture data to be transmitted may be automatically adjusted inversely proportional to the current transmission rate.

Therefore, even in the case of a sudden rise in the transmission rates of the moving picture date according to images being captured, data loss that may occur due to limitations in transmission capacity during the transmission may be prevented. Accordingly, distortion of the live-view moving picture data being displayed on the display115of the remote control center11may be also prevented. That is, a user may smoothly control the mobile robot12.