FIELD OF THE INVENTION

The present invention relates to a robot controller comprising a 0 control part for controlling at least one industrial robot and a portable operating control device, for teaching and manually op¬ erating the robot. The controller may also be used for controlling equipment associated to the robot.

5 PRIOR ART

An industrial robot is programmed to carry out work along an operating path. In order to program or teach the robot the path, the robot is manipulated to positions along the desired operating 0 path. These positions are stored as instructions in a memory in the controller. During operation of the robot, the program in¬ structions are executed, thereby making the robot work as de¬ sired.

5 An industrial robot can be operated in at least two different modes: automatic and manual. When the robot is in the manual operation mode, the robot is controlled by means of a portable operator control device, generally denoted a Teach Pendant Unit, and called hereafter a TPU . A robot operator uses a TPU 0 for manually controlling a robot, for example to teach or program the robot to follow an operating path. The TPU may also be used for monitoring a robot program, changing certain variables in the program, starting, stopping and editing the program. When the robot is in manual mode, the TPU has exclusive right to operate 5 the robot and thus no other control device is allowed to control the robot. A TPU normally comprises operator control means, for example a joystick, a ball, a set of buttons or any combination thereof, a visual display unit, and safety equipment including an enabling device. The enabling device enables or disables manual control of the robot by means of the TPU. The enabling device affects the current to the motors of the robot. When manual mode is se¬ lected and the enabling device is activated, it possible to manu¬ ally operate the robot by means of the TPU. When the enabling device is deactivated, it is not possible to manually operate the robot. If manual mode is selected it is possible to move the ro¬ bot, for example by means of the joystick, provided that the enabling device of the TPU is activated. In automatic mode it is not possible to move the robot with the TPU, even with the ena- bling device activated. The enabling device is for example a switch or a push button, which has to be pressed by the opera¬ tor to enable control of the robot by the TPU.

The status of the enabling device is either activated or deacti- vated. If the enabling device is a push button, the status of the enabling device is activated when the operator presses the but¬ ton, and the status of the enabling device is deactivated when the button is released. Some enabling devices have three posi¬ tions: a first position when the button is released, a second po- sition when the button is pressed, and a third position when the push button is pressed harder. In such cases the enabling de¬ vice is deactivated when the button is in the first and the third position.

For safety reasons the TPU is provided with either an emer¬ gency stop device or a stop device.

In order to facilitate the automation of complex series of actions under safe conditions, the robots can be placed in robot cells. Due to the considerable risk for twisting the cables, it is particu- larly advantageous to use a wireless TPU when there are sev¬ eral robots arranged near each other in a robot line.

From the international patent application WO03036324 it is known to use a wireless link for exchange of information be¬ tween the TPU and the robot controller.

From the Japanese patent application 1 1 -73201 and European patent application EP1 407 860, a wireless control system is previously known. The object of those applications is to provide a communication system wherein the specific communication of emergency stop control can be carried out by wireless means in a manner equivalent to cable communication.

OBJECTS AND SUMMARY OF THE INVENTION

The object of the present invention is to provide a controller in¬ cluding a wireless TPU.

This object is achieved by a controller as defined in claim 1 . Ac¬ cording to the invention, the TPU comprises: a plurality of de¬ tecting means, detecting the status of the enabling device, at least one communication data generating means, generating communication data including information regarding the de- tected status of the enabling device, and at least one wireless transmitting means, transmitting said communication data to said control part, and the control part comprises at least one re¬ ceiving means, receiving said communication data from said transmitting means and the control part is adapted to permit or not permit manual control of the robot by means of the TPU ba¬ sed on the received status of the enabling device.

The detection means detects whether the enabling device is ac¬ tivated or deactivated. In order to improve the safety and achieve redundancy, the TPU comprises a plurality of redundant detection means detecting the status of the enabling device. The TPU comprises at least one communication data generating means, generating communication data including information regarding the detected status of the enabling device. The com¬ munication data generating means comprises a communication data generating software process or a communication data gen¬ erating circuit. Thus, the communication data generating means is implemented either by means of software or hardware.

The communication data generating means generates mes- sages, including the communication data, according to any known communication protocol for wireless transfer to the con¬ trol part. A message may include information regarding the de¬ tected status from all of the detection means, or the detected status from one single detection means. In the latter case, one message is generated for each detection means. The control part comprises means for receiving the communication data from the TPU and for deciding to permit or not permit manual control of the robot by means of the TPU, based on the received status of the enabling device. The receiving means is adapted to generate an enabling signal based on the received communica¬ tion data.

The invention provides a portable TPU comprising a wireless enabling device. This makes it possible to eliminate the emer- gency stop button and still have the degree of security and safety, which the standard regulation provides.

According to an embodiment of the invention, the control part is adapted to permit manual control of the robot, if the status in- formation received from at least two of said detecting means in¬ dicates that the enabling device is activated. The control part is adapted to not permit manual control of the robot, if the status received from at least one of said detecting means indicates that the enabling device is not activated. Thus, it is possible to de- tect if any of the detecting means is defect and the safety of the controller is increased. According to an embodiment of the invention, the TPU com¬ prises a plurality of communication data generating means, which respectively correspond to each of said plurality of detect- ing means. The communication data generating means are re¬ dundant. Having a plurality of redundant communication data generating means makes it is possible to detect if any of the communication data generating means is defect and thus to in¬ creases the safety of the controller.

According to an embodiment of the invention, the TPU com¬ prises a plurality of wireless transmitting means, which respec¬ tively correspond to each of said plurality of communication data generating means. The wireless transmitting means are redun- dant. Having a plurality of redundant transmitting means makes it is possible to detect if any of the transmitting means is defect and thus to increases the safety of the controller.

According to an embodiment of the invention the receiving means comprises a plurality of receiving modules, which respec¬ tively correspond to each of the plurality of transmitting means and which receives communication data from the transmitting means. The receiving means are redundant. Having a plurality of redundant receiving means makes it is possible to detect if any of the receiving means is defect and thus to further in¬ creases the safety of the controller.

According to an embodiment of the invention, the control part is adapted to permit manual control of the robot as long as status information indicating that the enabling device is activated is re¬ ceived within a certain time frame. The control part is adapted to not permit manual control of the robot upon failure to receive status information from the enabling device within a certain time frame. Thus, the safety is further improved. According to an embodiment of the invention, the robot control¬ ler comprises a control part for controlling at least one industrial robot or associated equipment, and a portable operating device arranged to communicate with each other by at least one wire- less network wherein the portable operating device comprises a manually operated enabling device, which when continuously activated, permits motion of the robot and/or the associated equipment, and a plurality of communication data generating software processes or communication data generating circuits, which respectively generate communication data expressing an enabling device status command based on operation of said enabling device, and transmitting means which transmit commu¬ nication data expressing said enabling status command to said control part by wireless network communication; and the control part comprises receiving means which receives communication data expressing enabling status command from said transmitting means; wherein said receiving means place said robot or asso¬ ciated equipment in the enabling state according to the received enabling status command, which permits motion alternatively stop motion of the robot or associated equipment when receiving even a single set of communication data expressing an enabling status command generated by said plurality of communication data generating software processes or communication data gen¬ erating circuits.

The above-mentioned object is also achieved by means of a method for controlling an industrial robot according to claim 9.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be explained more closely by the descrip¬ tion of different embodiments of the invention and with reference to the appended figures.

Fig. 1 shows an industrial robot including a control part and a TPU. Fig. 2 shows a robot controller according to a first embodiment of the invention.

Fig. 3 shows a robot controller according to a second embodi¬ ment of the invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

Figure 1 shows an industrial robot comprising a manipulator 1 , a controller comprising a control part 3 for controlling the manipu¬ lator, and a portable operator control device 4, in the following denoted a TPU (Teach Pendant Unit) for teaching and manually operating the manipulator. The TPU 4 is communicating with the control part 3 via a wireless data link 5. The TPU comprises a display screen 6, function keys 8, a joystick 10, and an enabling device 12. The TPU also includes and antenna 14 and a radio module for wireless communication with the control part 3. The function keys 8 permit the operator to select various states for the control system. The joystick 10 is used for controlling the movement of the manipulator when the robot is manually oper¬ ated. The enabling device comprises a button 12, which has to be activated by the operator to enable manual control of the ro- bot by the TPU. When the operator deactivates the button of the enabling device 12, the robot can no longer be operated via the TPU.

Figure 2 shows a controller according to a first embodiment of the invention. The enabling device comprises two switches 16a- b connected to the button 12 of the enabling device. When the operator activates the button 12, the switches 16a-b closes, and when the operator deactivates the button 12, the switches 16a-b opens. The TPU 4 further comprises two detecting means 18a-b, means, which respectively correspond to each of the switches 16a-c, for detecting the status of the enabling device, i.e. de- tecting whether the button 12 is pressed or released, by detect¬ ing whether the switches 16a-b closed or opened. There are two switches and two detecting means to achieve redundancy and thus to improve the safety.

The TPU 4 further comprises a communication data generating means 20, generating communication data including information regarding the detected status of the enabling device. The data generating means is either implemented by hardware or soft- ware. The communication data generating means 20 generates communication data comprising one or more messages including information regarding the detected status of the enabling device from both detecting means 18a-b. A wireless transmitting means 14 transmits the communication data to the control part 3 of the controller. For example the communication data is transmitted by means of radiofrequency (RF), such as "bluetooth" or WLAN , or optically, such as infrared (IR). The communication data may also include other type of information such as a check sum for increasing the safety of the communication, the identity of the operator, the name of the robot and an IP-address.

The control part 3 is connected to a data communication link 21 , for example a data bus. For example, the data communication link 21 is part of a communication network. Other control units can be connected to the same network. An antenna 22 con¬ nected to the data communication link 21 receives the communi¬ cation data from the TPU . The control part 3 comprises receiv¬ ing means 24, receiving the communication data from the TPU and generating an enabling signal ES based on the received communication data. The enabling signal ES is a hardware sig¬ nal and is based on the received status of the enabling device. The enabling signal ES indicates whether or not manual control of the robot by means of the TPU is permitted or not.

The receiving means 24 extracts information regarding the de¬ tected status of the enabling device from the received communi- cation data. The receiving means 24 extracts the status de¬ tected by both detecting means 18a-b. The receiving means compares the status from both detecting means 16a-b. If the status information received from both detecting means indicates that the enabling device is activated, the control part will permit manual control of the robot provided that the robot is in manual mode. If the status received from any of the detecting means indicates that the enabling device deactivated, the control part will not permit manual control of the robot. The receiving means 24 is preferably implemented as program instructions in a com¬ puter program.

The control part also comprises one enabling circuit 26, often called an enabling chain, which is adapted to permits or not per- mit manual motion of the robot. The enabling circuit 26 com¬ prises a switch 28 that is opened or closed in dependence of the state of the enabling device, and a switch 30 that is opened or closed in dependence of whether the robot is in automatic or manual mode. A power supply V is connected to the enabling circuit. The enabling signal ES generated by the receiving means 24 controls the switch 28. If the robot is in automatic mode, the switch 28 is open and it is not possible to control the robot by the TPU . The enabling circuit 26 is connected to the motors M of the robot. When the robot is in manual mode and the switch 28 is open, the brakes are applied to the motors. Thus, the robot must be in manual mode and the enabling de¬ vice must be activated for the operator to be able to manually move the robot.

The receiving means 24 comprises a timer, which detects whether or not communication data is continuously received within a certain time frame. The receiving means 24 permits manual control of the robot as long as status information indicat¬ ing that the enabling device is activated is received within the certain time frame and do not permit manual control of the robot upon failure to receive communication data from the enabling device within the time frame. The time frame is for example cho¬ sen as the time it takes for the robot to move a distance, which is determined due to safety reasons.

The function of the controller according to the invention will be described in the following with reference to figure 2. The robot is put into manual mode and the switch 30 is closed, thereby the enabling chain is activated. As long as the enabling device 12 is deactivated, the switches 16a and 16b are opened, and as long as the operator activates the enabling device 12, the switches 16a and 16b are closed. The detecting means 18a detects the status of the switch 16a, and the detecting means 18b detects the status of the switch 16b. The communication data generating means 20 generates communication data including information regarding the detected status of the switches 16a and 16b, which correspond to the status of the enabling device. The re¬ ceiving means 24 of the control part 3 receives communication data from the TPU including information about the status of the switches 16a-b. The receiving means 24 is adapted to make a decision whether to close the switch 28 or not, based on the re¬ ceived status of the switches 16a and 16b. If the received status of both the switches 16a and 16b tells that the enabling device is activated, the switch 28 is closed and manual control of the robot by means of the TPU is permitted, for example motion of the robot by means of the joystick of the TPU is permitted. If the received status of at least one the switches 16a and 16b tells that the enabling device is deactivated, the switch 28 is opened and manual control of the robot by means of the TPU is not permitted.

Figure 3 shows a robot controller according to a second em¬ bodiment of the invention. Components corresponding to those in Figure 2 have been given the same reference numerals, and will not be described in more detail here. As can be seen in the drawing the TPU 4 comprises two communication data generat¬ ing means 20a-b, which respectively correspond to each of the two detecting means 18a-b. The TPU comprises two wireless transmitting means, in the form of two antennas 14a-b, which respectively correspond to each of the communication data gen¬ erating means 20a-b. The receiving means comprises two re- ceiving modules 25a-b and a comparator 27. The receiving modules 25a-b respectively correspond to each of the transmit¬ ting means 14a-b. The receiving modules 25a-b are connected to the data communication link 21 and receive communication data from the transmitting means 14a-b.

The receiving module 25a extracts information regarding the de¬ tected status of the enabling device from the communication data received from the communication data generating means 20a, and receiving module 25b extracts information regarding the detected status of the enabling device from the communica¬ tion data received from the communication data generating means 20b. The receiving modules 25a-b generate enabling signals ES1 , ES2, which indicates whether or not manual control of the robot by means of the TPU is permitted or not. A com- parator 27 compares the signals ES1 and ES2 and generates an enabling signal ES to the enabling circuit 26. The enabling sig¬ nal ES permits manual control of the robot if both signals ES1 and ES2 allows manual control and otherwise does not permit manual control.

The present invention is not limited to the embodiments dis¬ closed but may be varied and modified within the scope of the following claims. For example, in another embodiment the num¬ ber of switches of the enabling device, and the number of de- tecting means is more than two, for example three or four. In another embodiment, the control part may comprise two or more antennas, which respectively corresponds to each of a plurality of transmitting means.

The enabling device does not necessary has to be a push button or a switch, the enabling device may for example include a plate on the floor which is activated when the operator stands on it and is deactivated otherwise. The enabling device may also in¬ clude a defined area, which is activated when the operator en¬ ters the area and is deactivated when the operator leaves the area.