WO2009039896A1

WO2009039896A1 - System and method for measuring speed and/or distance in robot-assisted production and fabrication processes

Info

Publication number: WO2009039896A1
Application number: PCT/EP2008/002241
Authority: WO
Inventors: Jörg IHRIG
Original assignee: Abb Ag
Priority date: 2007-09-19
Filing date: 2008-03-20
Publication date: 2009-04-02
Also published as: AT512731A5; AT512731B1

Abstract

The invention relates to a system for measuring speed and distance in robot-assisted production and fabrication processes, wherein at least one radar sensor and a data processing device are provided, which data processing device interacts with the radar sensor and with which the speed and/or distance of at least one object, in particular a moving object, can be sensed, in particular by exploiting the Doppler effect, and/or can be converted into information that can be used for a control/adjustment device of at least one handling apparatus. Furthermore, the invention also relates to a corresponding method, with which a radar-controlled speed and distance measurement of at least one object, in particular an object moved by means of a transporting belt or conveyor belt, is carried out by using electromagnetic waves outside the visible spectrum and/or by exploiting the Doppler effect, and/or the data determined are converted into information that can be used for a control/adjustment device of at least one handling apparatus.

Description

System and method for speed and / or distance measurement in robotic production and manufacturing processes

description

The invention relates to a system and a method for speed and / or distance measurement in robotic production and manufacturing processes, wherein in particular the speed and / or distance of an object moved by means of a conveyor or conveyor belt relative to at least one handling device and / or a reference point, regardless of the prevailing lighting conditions, can be determined.

The use of robots in the field of automation, for example in painting and / or shit technology, or robotic automation is one of the most widespread applications in modern robot systems. To cope with increasingly complex automation tasks in the manufacturing sector, robots are increasingly being used, with the aid of which, in conjunction with the most universal production devices, numerous different product variations can be produced, wherein the robots and / or production devices used intelligently communicate and interact with their environment via a large number of sensors. One possible application is, for example, the feeding of one or more also different workpieces via a conveyor belt to a workstation with one or more robots. The timing plays thereby an essential role, wherein substantially speed and / or distance from the respective workpiece in relation to the workstation or the respective robot to determine and take into account.

Often, the workpiece or component is the respective handling device, in particular a multi-axis industrial robot, supplied for example by means of conveyor belts in any form. It is important to ensure that the speed of the conveyor belt and that of the robot are synchronized with each other.

A well-known method for speed measurement and / or synchronization is the so-called conveyor tracking, which can be used, for example, in painting, arc welding, picking and other applications, and in which, essentially, sensing wheels as well as optical monitoring and detection systems, in particular laser and camera systems also photoelectric sensors are used.

When Conveyor Tracking the speed of each conveyor belt, regardless of the transported object, for example, via a jockey wheel or other mechanical sensor or sensor can be detected or measured and can be passed to the control / regulating device of the respective handling device, in particular the respective robot. This is done in particular via a so-called encoder. The encoder converts the electrical impulses, which are sent from the clock or pulse generator to the control / regulating device, into reprocessable digital or analog values.

Such speed measurements and transmissions are well known and now industrial standard.

In addition, in addition to the feed rate of the respective workpiece in each production or fabrication process, the respective distance between the workpiece and handling system of importance, which can be determined for example by means of lasers of different classes and wavelengths. About in the Control / regulating integrable encoder, these pulses are converted into digital or analog values and / or usable information for the respective control / regulating device, which then, for example in the form of instructions, to the respective robot control for implementation to be passed or forwarded.

As a possible alternative to the jockey wheel, photoelectric sensors are also used as pulse generators. In this case, by means of two light barriers, which are mounted at a certain distance from each other in the direction of movement on the conveyor belt, the running speed of the respective conveyor belt detected or measured and passed on.

If the distance between the workpiece and the handling system or robot is also of importance in the respective production or production process, optical systems such as, in particular, lasers of different classes and wavelengths are used for distance determination. By means of encoders that can also be integrated into the open-loop / closed-loop control system, these pulses are also converted into digital or analog values and / or information that can be used for the respective control / regulating device, which then, for example in the form of instructions, is passed on to the respective robot controller for conversion or can be forwarded.

As a possible alternative, photoelectric sensors are used as pulse generators. In this case, two light barriers, which are mounted at a certain distance in the direction of movement on the conveyor belt, measure the speed of the conveyor belt and pass.

Through the use of conveyor or conveyor belts, the position of the workpiece in 2-dimensional space is clearly defined. Thus, a speed measurement together with a distance measurement and the knowledge of the position of the conveyor belt and its direction of movement relative to the handling device would be sufficient to synchronize the tool center of the handling device with the speed of the workpiece. Disadvantageously, conventional conveyor tracking systems accordingly require additional, as a rule, usually also maintenance-intensive and / or fault-prone mechanical and optical components and assemblies.

In particular, in the case of the optical components used, changing or changing light conditions in the environment of the respective workstation and / or contamination of the optical systems can disadvantageously lead to an impairment of the measurement accuracy and / or serviceability of the same. To compensate for this, corresponding light sources and lighting systems are installed with comparatively high expenditure in order to ensure consistent and extremely homogeneous lighting conditions.

In addition, at least two different systems or arrangements must generally be used, operated, maintained and linked with the respective control / regulating device of the at least one handling device for speed and distance determination.

An efficient speed and distance determination with at the same time comparatively little effort is not possible in this way.

The invention is thus based on the object of specifying a possibility for efficient synchronization and / or coordination of the movement of an object, in particular a workpiece, and a handling device.

This object is achieved by a system of the type mentioned with the features of claim 1.

Advantageous embodiments and further developments of the invention and a corresponding method are specified in further claims and the following description.

Accordingly, the system for speed and distance measurement in robotic production and manufacturing processes, at least one Radar sensor and a data processing device, which cooperates with the respective radar sensor and, in particular taking advantage of the Doppler effect, speed and / or distance of at least one object, in particular a moving object detectable and / or usable for a control / regulating device at least one handling device information are convertible.

Advantageously, it can be provided that radar sensor and data processing device each have a wireless or wired communication connection, in particular a LAN, WLAN or WAN, for example, the type Ethernet, Bluetooth, or other common bus type, such as CAN, CANOPEN, Profibus, Modbus, but also USB , RS-232, SCSI or the like.

In an advantageous embodiment, the system comprises at least one interface via which the converted information of the control / regulation device of at least one handling device, in particular one or more six-axis industrial robots, can be supplied or transmitted.

Also, the aforementioned interface can be wired or wireless in nature, for example, as Ethernet, Bluetooth, CAN, CANOPEN, Profibus, Modbus, but also USB, RS-232 or SCSI interface or a combination thereof be.

According to the system, electromagnetic waves are generated outside the visible light by means of the respective radar sensor.

The associated transmission frequencies move by way of example in the range of 76-77 GHz, corresponding to a wavelength of about 4 mm. A measurement in the transmission frequency range of for example 24 GHz is advantageously possible.

The corresponding radar sensors in particular comprise both a transmitting device and a receiving device for radar waves Frequency. Further education transmitting and receiving device can also be integrated in a device.

For each measurement the Doppler effect is used. The Doppler effect is the change in the frequency of the waves of any kind, including radar or ultrasonic waves, while the source and measuring body, in this case in particular the workpiece, move relative to one another, that is to say, for example, the source moves towards or onto the body moving away from it or the body moving towards or away from the source. Through this change in frequency, various information can be passed to the control / regulating device of the respective handling device. From the time difference between transmission of the wave and its reception after the reflection at the respective object or measuring body, in particular a workpiece to be processed, the distance of the illuminated object can be measured, whether the system moves to the viewer or away and from the pursuit of individual Measuring points its speed and direction relative to the handling device and / or a predeterminable reference point.

In another embodiment, at least one radar sensor comprises an FMCW (Frequency Modulated Continous Wave) radar, a "Modulated CW Radar" or an FM radar, wherein the different types of radar can also be used in combination.

These radars transmit at a constantly changing frequency. At least two operating modes can be distinguished. The frequency either increases linearly to abruptly decrease to the initial value at a certain frequency, or it increases and decreases alternately at a constant rate of change.

Advantageously, it can furthermore be provided that the data processing device comprises a decoder or decoder or coder for signal or pulse or signal processing and / or information provision. By means of the decoder, a provision of data / information in accordance with the tool speed and / or removal during the production process is accordingly feasible.

Furthermore, the object is achieved by a corresponding method for speed and / or distance measurement in robotic production and manufacturing processes, in particular by means of an aforementioned system, a radar-controlled speed and distance measurement of at least one object, in particular an object moved by means of a conveyor or conveyor belt using electromagnetic waves outside the visible spectrum and / or utilizing the Doppler effect, and / or converting it into information usable for a control device of at least one handling device.

In a further development of the method, the usable information for the implementation via a corresponding communication link to the control / regulating device at least one handling device, in particular a multi-axis industrial robot, transmitted and / or used for synchronization and tuning of the movements of handling device and object, in particular workpiece.

In an advantageous embodiment, a plurality of radar sensors are used for speed and / or distance measurement. In this case, a sensor comprises both a transmitting and a receiving device, wherein the transmitting device generates and transmits electromagnetic waves of suitable transmission frequency or wavelength, and the receiving device receives and registers the waves reflected by one or more objects, in particular workpieces. By the time shift between transmission and reception or by the propagation delay of the wave, with knowledge of the propagation speed, the distance to the respective object can be determined. Taking advantage of the Doppler effect and by determining a possible frequency shift, the speed and direction of the respective object, in particular the respective workpiece can be determined. In a further method embodiment, at least one radar sensor is used in the form of an FMCW (Frequency Modulated Continuous Wave) radar, a "Modulated CW Radar" or an FM radar, the different types of radar also being usable in combination.

It can also be advantageously provided that, according to the method, at least one data processing device is used which has a decoder or decoder or coder for signal or pulse or signal processing and / or information provision.

By means of the decoder, a provision of data / information in accordance with the tool speed and / or removal during the production process is accordingly feasible.

Advantageously, it can be provided that radar sensor and / or data processing device and / or control device of at least one handling device in each case via a wireless or wired communication connection, in particular a LAN, WLAN or WAN, for example, the type Ethernet, Bluetooth, or other common bus type For example, CAN, CANOPEN, Profibus, Modbus, but also USB, RS-232, SCSI or the like work together.

With the present invention it is achieved that the number of electronic and mechanical components in the measurement is reduced. In addition, errors and disturbances due to mechanical wear of the clock or defect of the sensor changing light conditions are largely avoidable, creating an efficient speed and distance measurement and associated with a efficient synchronization and coordination of handling device and conveyor belt and / or moving object is made possible.

The further explanation of the invention is based on the single figure and the associated embodiment.

Further advantageous embodiments and developments of the invention can be removed in the single figure and the associated description.

In Fig. 1 is an exemplary trained system for speed and distance measurement in robotic production and manufacturing processes, wherein at least one radar sensor (1) and a data processing device (2) are provided, which data processing device (2) with the respective radar sensor (1) cooperates and with which, in particular taking advantage of the Doppler effect, speed and / or distance of at least one by means of a transport (4) or conveyor belt moving object (6) detectable and / or the detected data in for a control / ruleeinhchtung (8) at least a handling device (10), in the example shown here a six-axis industrial robot, in particular a welding and / or painting robot, usable information can be converted.

The radar-based system as well as methods executable thereon advantageously permit a determination of the speed and / or the distance of an object in relation to a predeterminable reference point, whereby additional maintenance-intensive mechanical components or external measuring sensors such as light barriers and the like are avoided.

Claims

claims

1. System for speed and distance measurement in robotic production and manufacturing processes, wherein at least one radar sensor and a data processing device are provided, which data processing device cooperates with the respective radar sensor and with which, in particular taking advantage of the Doppler effect, speed and / or distance of at least one object , in particular a moving object can be detected and / or converted into usable for a control / regulating device of at least one handling device information.

2. System according to claim 1, characterized in that radar sensor and data processing device respectively via a wireless or wired communication connection, in particular a LAN, WLAN or WAN, for example, the type Ethernet, Bluetooth, or other common bus type, such as CAN, CANOPEN, Profibus , Modbus, but also USB, RS-232, SCSI or the like.

3. System according to any one of the preceding claims, characterized in that at least one interface is provided, via which the converted information of the control / regulating device of at least one handling device, in particular one or more multi-axis industrial robots, zuleitbar or can be transmitted.

4. System according to claim 3, characterized in that the interface is wired or wireless, in particular as Ethernet, Bluetooth, CAN, CANOPEN, Profibus, Modbus, but also USB, RS-232 or SCSI Interface or a combination thereof.

5. System according to any one of the preceding claims, characterized in that by means of the respective radar sensor electromagnetic waves outside of In particular, transmission frequencies in the range of 76-77 GHz, corresponding to a wavelength of about 4 mm, or in the transmission frequency range of about 24 GHz can be generated.

6. System according to any one of the preceding claims, characterized in that the radar sensors comprise both a transmitting device and a receiving device for radar waves suitable frequency and / or transmitting and receiving device can be integrated in a device.

7. System according to one of the preceding claims, characterized in that at least one radar sensor as FMCW (frequency modulated continuous wave) radar, "Modulated CW radar" or FM radar is formed.

8. System according to one of the preceding claims, characterized in that the data processing device comprises a decoder or decoder or encoder for signal or pulse or signal processing and / or information provision.

9. A method for speed and / or distance measurement in robotic production and manufacturing processes, wherein, in particular by means of a system according to one of claims 1 to 8, a radar-controlled speed and distance measurement of at least one object, in particular one moved by means of a conveyor or conveyor belt Object using electromagnetic waves outside the visible spectrum and / or utilization of the Doppler effect, carried out and / or the determined data are converted into usable for a control device of at least one handling device information.

10. The method according to claim 9, characterized in that the usable information for implementation via a corresponding communication link to the control / regulation device at least one handling device, in particular a multi-axis industrial robot, transmitted and / or used for synchronization and tuning of the movements of handling device and object, in particular workpiece.

11.Verfahren according to any one of claims 9 or 10, characterized in that for speed and / or distance measurement a plurality of radar sensors are used, wherein a sensor thereby comprises both a transmitting and a receiving device and / or the transmitting device electromagnetic waves suitable transmission frequency or Wavelength generated and transmits and the receiving device receives at one or more objects, in particular workpieces, reflected waves, and registered.

12. The method according to any one of claims 9 to 11, characterized in that the distance to the respective object is determined by the time shift between transmission and reception or by the transit time of the wave, with knowledge of the propagation speed, and / or taking advantage of the Doppler effect and by Determining a possible frequency shift, the speed and direction of the respective object, in particular the respective workpiece is determined.

13. The method according to any one of claims 9 to 12, characterized in that at least one radar sensor in the manner of an FMCW (frequency modulated continous wave) radar, a "Modulated CW radar" or an FM radar used, wherein the different radar types also used in combination.

14. The method according to any one of claims 9 to 13, characterized in that at least one data processing device is used which has a decoder or decoder or encoder for Signalbeziehungsweise pulse or signal processing and / or information provision.

15. The method according to claim 14, characterized in that by means of the decoder is also a provision of data / information bereffend the tool speed and / or removal in the production process is performed.

16. The method according to any one of claims 9 to 15, characterized in that the radar sensor and / or data processing device and / or control / regulating device at least one handling device in each case via a wireless or wired communication connection, in particular a LAN, WLAN or WAN, for example, the type Ethernet , Bluetooth, or any other common bus type, such as CAN, CANOPEN, Profibus, Modbus, but also USB, RS-232, SCSI, or the like.