The present invention relates to a movement indicator that indicates coming robot movements to persons in the vicinity of the robot.

BACKGROUND ART

It is previously known to indicate coming robot movements to improve safety of an operator of a robot. JP2013086223 discloses a robot equipped with a movement indicator

disposed at a robot arm. The movement indicator is thereby an integral part of the robot and comprises a spherical member with an assembly of display pixels. The pixels are lighted or blinked along the moving direction of the robot arm. A drawback with the aforementioned known movement indicator is that as it is an integral part of a robot it is difficult to integrate into an existing robot. Another drawback is that the weight of the movement indicator needs to be carried by the robot. There therefore remains a desire to provide a movement indicator the use of which does not require any extensive changes to be done to the construction of the robot, and that does not negatively affect the payload of the robot.

SUMMARY OF THE INVENTION One object of the invention is to provide an alternative movement indicator that can in an easy way be used in combination with any existing robot. These objects are achieved by the device according to appended claim 1.

The invention is based on the realization that by providing a movement indicator with dimensions that correspond to a work area size of the robot the movement indicator can easily be configured to indicate movements of any existing robot with a corresponding work area size.

According to a first aspect of the invention, there is provided a movement indicator for a robot. The movement indicator is configured to indicate coming robot movements, and it comprises visual indicators for indicating the coming robot movements, and communication means configured to communicate with a robot controller. The movement indicator comprises a planar member configured to indicate the coming robot movements projected to a corresponding first plane.

According to one embodiment of the invention, the planar member comprises a mat configured to be placed under the robot .

According to one embodiment of the invention, the visual indicators comprise arrays of lamps.

According to one embodiment of the invention, the arrays of lamps emit light in different colours.

According to one embodiment of the invention, the emitted colour indicates a coming time period. According to one embodiment of the invention, the emitted colour indicates a speed of the robot movement.

According to one embodiment of the invention the movement indicator further comprises an auditory indicator for indicating robot movements. According to one embodiment of the invention the movement indicator further comprises a vibratory indicator for indicating robot movements.

According to one embodiment of the invention the movement indicator further comprises at least one a pressure sensor for sensing a force on the movement indicator.

According to one embodiment of the invention the movement indicator further comprises a distance indicator configured to indicate robot movements in a direction perpendicular to the first plane.

According to a second aspect of the invention, there is provided a robot system comprising a robot and a movement indicator according to the description hereinbefore.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be explained in greater detail with reference to the accompanying drawings, wherein figure 1 shows a robot system comprising a robot and a

movement indicator according to one embodiment of the invention. DESCRIPTION OF PREFERRED EMBODIMENTS

Referring to figure 1, a movement indicator 10 according to one embodiment of the invention comprises a mat 20 on which a robot 30 is to be placed. The mat 20 has a round form and the robot 30 is placed in the middle of the mat 20. The mat 20 comprises arrays of led lamps 40, each led lamp 40 being capable of emitting light in different colours. The arrays extend in radial directions from the middle of the mat 20 towards the periphery of the same. There are twenty arrays of led lamps 40 with an angular distance of 18 degrees between each pair of neighbouring arrays, each array

comprising ten led lamps 40. In addition there are two led lamps 40 between each pair of neighbouring arrays close to the periphery of the mat 20. The movement indicator 10 comprises an indication controller 50 configured to control the status of each led lamp 40.

A robot controller 60 controls movements of the robot 30. The robot controller 60 calculates a robot path before providing instructions to execute respective robot

movements, and thereby the robot controller 60 typically has knowledge about coming robot movements relatively long time before the movements are executed. The indication controller 50 comprises a communication means 70 configured to

communicate with the robot controller 60 in order to be informed about the coming robot movements. The indication controller 50 then turns this information into visual signals by turning on and off the led lamps 40 in

appropriate colours to indicate the coming robot movements. The indication controller 50 may be integrated to the robot controller 60 such that the two devices share a common hardware .

The mat 20 is a planar member that indicates robot movements projected to a plane of the mat 20. The mat 20 is thereby able to indicate a movement area 80 which is an area within which the projection of certain (moving) parts of the robot 30 in the plane of the mat 20 stay during a certain period of time. The movement indicator 10 can e.g. be configured to indicate the movements of a robot tool 90, or it can be configured to indicate the movements of all moving parts of the robot 30 including different robot arms 100 and a robot wrist 110. A movement area 80 may represent robot movements e.g. over next three seconds projected to the plane of the mat 20. All the led lamps 40 within the movement area 80 may be turned on to indicate such movement.

As an example, a first movement area 80 is illustrated with a solid line in figure 1 to indicate an area representing robot movements over the next three seconds projected to the plane of the mat 20. The led lamps 40 within the first movement area 80 are furthermore divided into three area groups whereof a first area group 120 is illustrated with a dashed line and represents robot movements over the next one second (including the current position) . The led lamps 40 within the first area group 120 are controlled to emit red light. A second area group 130 is illustrated with a dash- dot line and represents robot movements within a time period between one and two seconds from the current point in time. The led lamps 40 within the second area group 130 are controlled to emit orange light. The remaining led lamps 40 within the first movement area 80 form a third area group 140 that represents robot movements within a time period between two and three seconds from the current point in time. The led lamps 40 within the third area group 140 are controlled to emit yellow light. It is not excluded that the robot movements during the time period between one and two seconds from the current point in time may also correspond to the first area group 120 in part or in total, or that the robot movements during the time period between two and three seconds from the current point in time may also correspond to the first and second area groups 120, 130 in part or in total .

The movement indicator 10 according to figure 1 furthermore comprises an upright pole 150 with a column of led lamps 40. Together with the mat 20 the pole 150 enables indication of coming robot movements in three dimensions. The example of figure 1 shows a first movement distance 160 corresponding to the first movement area 80, and a first, second and third distance groups 170, 180, 190 corresponding to the first, second and third area groups 120, 130, 140 and representing the respective time periods. The led lamps 40 within the first movement distance 160 thereby indicate a distance interval representing robot movements over the next three seconds projected to the axis of the pole 150 i.e. in a direction perpendicular to the plane of the mat 20. Together the first movement area 80 and the first movement distance 160 define a first movement volume (not shown) of what an operator gets a visual indication.

The movement indicator 10 may indicate not only positions of coming robot movements but also other parameters such as speed. For example, the led lamps 40 may be controlled to blink at a certain frequency proportional to the speed of the robot movements. The blinking frequency may for example be 0,5 Hz at zero speed of the robot tool 90, 3 Hz at maximum speed of the same, and increase linearly from 0,5 Hz to 3 Hz in proportion to the speed from the zero speed to the maximum speed of the robot tool 90. Alternatively, instead of indicating different coming time periods, the different emitted colours may indicate the speed of the robot movement. For example, a red colour may indicate a fast movement, an orange colour may indicate a moderate movement, and a yellow colour may indicate a slow movement.

The movement indicator 10 may provide not only visual indications but also other types of indications such as auditory or vibratory indications. For example, the movement indicator 10 may comprise a buzzer that generates voice signals at a certain frequency proportional to the speed of the robot movements. The voice signal frequency may for example behave in a corresponding manner than the blinking frequency described hereinbefore. The movement indicator 10 may furthermore comprise a vibrator that generates a

vibrating alert. For example, the mat 20 of figure 1 may comprise an integrated vibrator that generates a vibrating alert if an operator is standing on the mat 20 at a position where the robot 30 is about to move. The sensing of the presence of an operator on the mat 20 can in its turn be based on pressure sensors integrated to the mat 20 and reacting on a force exerted on the mat 20.

The invention is not limited to the embodiments shown above, but the person skilled in the art may modify them in a plurality of ways within the scope of the invention as defined by the claims.