Industrial Robot Control Systems

Abstract

To provide a controlling system of an industrial robot capable of enhancing the precision of operation of the industrial robot, by merging data sensed with a tool monitoring unit mounted posteriorly to the industrial robot performing autonomous operation control, with internal information such as the CNC of the industrial robot.SOLUTION: An in-robot controller conducts force control based on a detection value of an in-robot detector, while performing control of a robot by using information on a posture of the robot and a detection value of a displacement amount detector when a predetermined movement / rotational action is carried out by the industrial robot. A tip of the robot is connected with a tool monitoring unit that grips a machining tool performing prescribed machining on a machining object part of a workpiece, and that moves and / or rotates in cooperation with the robot. The tool monitoring unit comprises: a machining tool detector which successively detects force generated in the machining tool; and an interruption controller which corrects a control signal of the in-robot controller according to the detection value of the machining tool detector and the detection value of the in-robot detector of the same time axis.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an industrial robot control system that can improve the precision of industrial robot operations by combining data sensed by a tool monitoring unit attached after the fact with internal information such as the CNC of the industrial robot, in an industrial robot that performs autonomous operation control based on feedback from monitoring various phenomena. [Background technology]

[0002] In recent years, as machining technology has become more precise, the tasks performed by industrial robots have become more complex and sophisticated, and advances in IoT (Internet of Things) technology have led to demands for autonomous operation based on sensing technology and detection data for industrial robots. In industrial robots, such as so-called six-axis machining robots, the robot's movement, tilt, tool rotation speed, and other operations (also referred to as "machining control") are controlled using computerized numerical control (CNC) or other systems (hereafter referred to as "CNC" in this specification). However, industrial robots are now required to not only perform simple machining control, but also monitor various phenomena and feed back that data to autonomously control their operations.

[0003] In recent years, advances have been made in the development of industrial robots (hereinafter also referred to as "collaborative robots") that can cooperate with humans without safety fences, as an example of the use of autonomous operation control based on feedback from monitoring various phenomena. Unlike normal machining operations, safety control, such as stopping operation, is performed in the event of human contact or collision or interference between the robot and other parts (also referred to as "abnormality control": see Patent Document 1). Generally, abnormality control in collaborative robots involves using contact sensors to measure the load applied when contact or interference occurs between humans, robot parts, peripheral devices, etc., and, when a predetermined condition is met, interrupting the internal information of the CNC to stop the operation of the collaborative robot (see Patent Document 2). There is a great need for highly accurate machining control using internal CNC information in autonomous control such as abnormality control.

[0004] However, in actual manufacturing sites, machining control is often complex, and there are limits to correcting high-precision machining control using the autonomous control installed in collaborative robots with large inertial weights. For example, when using a collaborative robot to perform polishing work (processing) that requires high precision on complex shapes, it is difficult to achieve autonomous control using data from the contact sensors built into the robot, and there has yet to be a provision of an IoT-compatible collaborative robot that can perform autonomous control using internal servo information and wireless communication functions.

[0005] Meanwhile, the present applicant has been working on the development of a machining tool monitoring unit that is retrofitted to the tip of the spindle as a post-process replacement and monitors the temperature / vibration / force of tools and other components in machining equipment such as machining centers, and has provided a device that detects data obtained from this monitoring device and transmits it externally for analysis (see Patent Document 3, etc.). Furthermore, this machining tool monitoring device also provides a technology that performs external interrupt processing to correct the internal CNC information of the machining equipment (see Patent Document 4). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 2019-130646 [Patent Document 2] Japanese Patent Application Publication No. 2020-163478 [Patent Document 3] Japanese Patent Application Laid-Open No. 2017-140696 [Patent Document 4] International Publication WO2020 / 149316 Summary of the Invention [Problem to be solved by the invention]

[0007] In view of the above circumstances, the present invention aims to provide an industrial robot control system for an industrial robot, such as a collaborative robot, that performs autonomous operation control based on feedback from monitoring various phenomena, in which detection information from the machining tool monitoring unit attached to the tip of the spindle is fed back to the industrial robot and combined with internal information on the numerical values ​​of the industrial robot's CNC or other computer, thereby improving the speed and precision of the industrial robot's operation.At the same time, the present invention also aims to provide an industrial robot control system that feeds back internal information on the numerical values ​​of the industrial robot's CNC or other computer to a machining tool monitoring device and combines it with the detection information. [Means for solving the problem]

[0008] In order to achieve the above object, the industrial robot control system of the present invention specifically comprises: an industrial robot that is displaceable relative to a workpiece placed on a stage and performs predetermined processing on a non-processing target portion of the workpiece; a robot internal control unit that controls the posture of the industrial robot and the predetermined movement / rotation operation; a displacement amount detection unit that successively detects the amount of displacement of the industrial robot relative to the workpiece during a predetermined processing; and an in-robot detection unit that detects a force generated by contact between at least a part, a workpiece, or an external object supported by the industrial robot and the industrial robot or a part supported by the industrial robot, The robot internal control unit an industrial robot system that performs force control based on a detection value of a detection unit in the robot while controlling the robot using information on the posture of the robot and a detection value of the displacement amount detection unit when the industrial robot performs the predetermined movement / rotation operation, A tool monitoring unit is connected to the tip of the robot, which holds a machining tool that performs a specified machining operation on the portion of the workpiece to be machined and moves and / or rotates in cooperation with the robot, and the tool monitoring unit includes at least a machining tool detection unit that sequentially detects the forces acting on the machining tool, and an interrupt control unit that corrects a control signal for the robot's internal control unit based on the detection values ​​of the machining tool detection unit and the robot internal detection unit on the same time axis.

[0009] The present invention provides a control system for industrial robots such as collaborative robots that perform the autonomous operation control described above, in which contact and interference with people, parts, etc. is monitored by a contact force detection unit (contact sensor), and data on the posture (position, tilt, etc.) detected by a displacement detection unit is fed back to correct internal information of a control unit within the robot such as a CNC, thereby stopping operation in that posture.An industrial robot control system is provided that improves the precision of the operation of a collaborative robot by correcting internal information of the robot's CNC, etc. based on data obtained from a tool monitoring unit (machining tool monitoring device) that senses machining tools such as added tools.

[0010] As will be described in more detail below, the inventors, intending to improve the machining accuracy of collaborative robots, used a tool monitoring unit for which the applicant has technology to detect and analyze real-time phenomena of force, temperature, and vibration of tools such as tools during workpiece machining. In the process, the inventors found that, when compared with internal information sensed by the collaborative robot for autonomous operation control, the two sets of data had a stable linear relationship (hereinafter, sometimes simply referred to as "synchronized"), at least with respect to force. This finding led to the development of the present invention, which, in industrial robots that perform autonomous operation control, such as collaborative robots, makes it possible to improve the precision of control of the industrial robot's posture, etc., by correcting the numerical values ​​of a computer such as a CNC on the robot side based on real-time detection values ​​of phenomena of a separate machining tool such as a tool.

[0011] It is also preferable that the tool monitoring unit calculates the force detection value detected by the processing tool detection unit from the force detection value detected by the in-robot detection unit on the same time axis.

[0012] In particular, with industrial robots such as collaborative robots that perform polishing, when it is necessary to recognize the load on a workpiece, it has been discovered that a force sensor based on the robot (placed on a base, etc.) that can obtain data in the robot space coordinate system, which is an absolute coordinate, is advantageous, and that it can also fully obtain the load on processing tools such as tools.Based on this knowledge, in this industrial robot control system, data based on relative coordinates from this tool monitoring unit, which senses the force applied to processing tools such as tools, can be evaluated as a robot space coordinate system of absolute coordinates on the same time axis.

[0013] Furthermore, the processing tool detection section of the tool monitoring unit can successively detect the force, vibration and / or heat generated in the processing tool.

[0014] In this industrial robot control system, the tool monitoring unit measures heat and vibration in addition to force, enabling highly accurate control of the industrial robot. In particular, with industrial robots such as collaborative robots that perform polishing, it has been found that the amount of cutting into the workpiece is highly dependent on the vibration and temperature of the processing tool. By measuring the temperature and vibration of the polishing surface (the surface of the polishing tool), it is possible to control the amount of cutting, which is an important factor in accurate polishing of the workpiece, and achieve even more accurate polishing.

[0015] Preferably, the temperature successively detected by the processing tool detection unit is detected by at least one non-contact external thermometer disposed facing the direction of any processing surface of the processing tool relative to the workpiece.

[0016] When polishing is performed using an industrial robot such as a collaborative robot as described above, it is sufficient to arrange one non-contact external thermometer such as an inexpensive infrared temperature sensor in any direction of the machining surface of the machining tool relative to the workpiece (for example, any radial direction of the machining tool), providing a simple and inexpensive monitoring and control method.

[0017] Furthermore, the vibrations successively detected by the machining tool detection unit can be detected by an acceleration sensor that detects vibration accelerations in the translational and vertical directions of the machining tool relative to the workpiece.

[0018] Furthermore, the tool monitoring unit can compare the detection value of the machining tool detection unit, the detection value of the robot internal detection unit, and / or the detection value of the displacement amount detection unit on the same time axis, and correct the control of the robot internal control unit using the interrupt control unit.

[0019] This industrial robot control system achieves higher precision machining by combining and analyzing, on the same time axis, the detection data of machining tools such as tools detected by the machining tool detection section of the tool monitoring unit and the internal information, which is the detection data from the industrial robot itself, and by automatically correcting the internal information, such as the CNC, on the robot's side based on the results. In particular, while conventionally, the internal information, which is computer numerical values ​​such as CNC, was corrected by a control unit installed in each industrial robot by the equipment manufacturer to control operation for higher precision and safety, this industrial robot control system has a major advantage in that it can be applied to various industrial robots and has a basic configuration that can provide a universal system that can achieve higher precision in robot control according to the type of machining. [Effects of the Invention]

[0020] According to the industrial robot control system of the present invention, in an industrial robot such as a collaborative robot that performs so-called autonomous operation control by monitoring various phenomena, the detection information from the tool monitoring unit attached to the tip of the spindle can be combined with internal information from the industrial robot's CNC, etc., to improve the precision of the industrial robot's operation. At the same time, internal information from the industrial robot's CNC, etc. can be fed back to the tool monitoring unit and combined with the detection information. [Brief explanation of the drawings]

[0021] [Figure 1] This is a photograph showing the pressure points when verifying force detection by the robot internal detection unit and the machining tool detection unit in this industrial robot control system, and the layout of the mounted grinding wheel and peripheral sensors in the tool monitoring unit. [Figure 2] This figure shows the experimental setup for measuring temperature using an infrared temperature sensor and an infrared thermography camera. [Figure 3] This shows the setup of the experimental equipment for monitoring force, heat, and vibration during machining using a base force sensor, infrared temperature sensor, and wireless vibration measurement system. [Figure 4] The present invention relates to an industrial robot control system, a processing tool detection unit of a tool monitoring unit, and a wireless vibration monitoring system for detecting vibrations. [Figure 5] This is a schematic diagram of the workpiece shape, tool (machining tool) trajectory, and sensing position for monitoring the force, temperature, and vibration when polishing the periphery of the workpiece, which was conducted as a demonstration experiment. [Figure 6] The left and right columns are graphs showing the relationship between the applied pressure at points 1 and 2 in FIG. 1 and the average values ​​per second of system variables 1-3 (upper to lower rows) of the hand force sensor. [Figure 7]The left and right columns are graphs showing the relationship between the applied pressure at points 1 and 2 and the one-second average values ​​(horizontal axis) of system variables 1-3 (upper to lower rows) of the base force sensor. [Figure 8] This is a photograph of the heat generated during polishing, taken with an infrared thermography camera from point c (90°) shown in Figure 2. [Figure 9] FIG. 10 is a graph showing that the temperature becomes constant in the tool radial direction not only when the temperature is saturated but also from the rise of the temperature. [Figure 10] FIG. 10 is a graph showing plots of changes in the rotation speed of the tool for each depth of cut 10 seconds after the start of pressing. [Figure 11] This is a graph showing the average values ​​of temperature, vibration acceleration, and force from each sensor, as well as changes in cutting depth. [Figure 12] FIG. 10 is a graph showing average values ​​of monitored polishing efficiency during each reciprocation at each depth of cut. [Figure 13] FIG. 13 is a photograph showing the observation results of the surface texture during monitoring in FIG. 12. DETAILED DESCRIPTION OF THE INVENTION

[0022] The following is an outline of the industrial robot control system of the present invention. In particular, the specification focuses on an example in which a collaborative robot having a force sensor for detecting contact with a person or the like performs polishing of a workpiece with a complex shape using a tool held at the tip of the spindle, and describes findings obtained as a result of a demonstration experiment in which the force, vibration, and temperature of the tool are detected by an internal robot detection unit in the collaborative robot and a processing tool detection unit in the tool monitoring unit, and the data wirelessly transmitted to the outside is analyzed. At the same time, the specification describes an industrial robot control system in which a new polishing system is constructed that utilizes the internal information of the force sensor for contact detection as the internal detection unit of the robot to improve the polishing process.

[0023] Collaborative robots for polishing work and obtaining internal CNC information The industrial robot used in this demonstration experiment was a 6-axis collaborative robot (FANUC: CR-7iA / L) with a 7 kg payload, consisting of J1-J6 axes. It has a force sensor (Force sensor (Base)) on the base (a component of the collaborative robot) directly below the J1 axis at the base as the robot's internal detection unit. This force sensor on the base is used to recognize contact with a person or other object, and the industrial robot control system acquires CNC system variables (internal parameters) as output values ​​from the force sensor and wirelessly outputs them to an external PC. The collaborative robot also has a force sensor (Force sensor (Hand) (FANUC: FS-15iA)) attached to the tip of its J6 axis, and this output value was similarly acquired as a CNC system variable by the industrial robot control system and output externally. The example of this industrial robot control system shown here is a robot system for polishing work in which an Air Leutor (UHT: MSG-3BSPlus) is attached as a tool (processing tool) via a jig to the tip of this tool monitoring unit (Wireless Vibration Monitoring System (Yamamoto Metal Works: MULT INTELLIGENCE)) which is attached to the tip of the collaborative robot. Figure 1 shows the pressure points when force detection was verified in the robot's internal detection unit and the processing tool detection unit in this industrial robot control system, and force detection was carried out at pressure points 1 and 2.

[0024] <<Polishing tools (processing tools), wireless transmission, and external sensors>> Multiple sensors (displacement detection unit, robot internal detection unit, machining tool detection unit, etc.) were attached around the air router at the tip of this tool monitoring unit, and a rotary tool was attached to the tip of that. The layout of the rotary tool and surrounding sensors in this tool monitoring unit is shown in Figure 1. The sensors used in the demonstration experiment are listed in Table 1 below. [Table 1]

[0025] In addition, in the demonstration experiment, to confirm the heat generated during the polishing process, temperature measurements were taken using an infrared temperature sensor and an infrared thermographic camera, as shown in Figure 1. The experimental equipment settings at that time are shown in Figure 2, and the polishing conditions are shown in Table 2 below. A thermomobile detection type infrared temperature sensor was used, and temperature information at a point on the grinding wheel during the polishing process, located 3 mm from the bottom of the wheel, was obtained from one direction (180° opposite to the X-axis from point a in Figure 2). [Table 2]

[0026] Additionally, an infrared thermography camera was used to capture images of the tool surface temperature from three directions (30°, 90°, and 150° counterclockwise around the X axis from points b, c, and d in Figure 2). In order to confirm changes in force, temperature, and vibration when the depth of cut was changed during this polishing process, the tool monitoring unit was equipped with the above-mentioned base force sensor, infrared temperature sensor, and a wireless vibration measurement system; using these, we attempted to monitor the force, heat, and vibration during processing. The experimental equipment settings at that time are shown in Figure 3, and the polishing process conditions are shown in Table 3 below. [Table 3]

[0027] As an example of vibration detection in the machining tool detection section of this tool monitoring unit, an example configuration of a wireless vibration monitoring system and a method for monitoring vibration acceleration are shown in Figure 4. The left column of Figure 4 shows an example of the main configuration of this tool monitoring unit, which is connected to the spindle so that it rotates cooperatively with it, and four piezoelectric acceleration sensors (4X acceleration sensors (see the right column of Figure 4)) with sensitivity in one axis direction are arranged at equal intervals on the same circumference inside a small case (Wireless Vibration Monitoring System) on the spindle side above this tool monitoring unit.

[0028] The circumferential accelerations ax1 and ax2 of the sensors, which are placed on opposite sides in the upper and lower radial directions, have positive sensitivity in the direction of the double arrows shown in the right column of Figure 4, and Xm, as one axial direction, is calculated by differential calculation (analog op amp calculation) of the vibration acceleration at (ax1-ax2) / 2, canceling out the rotational vibration component. Similarly, it is possible to monitor vibration acceleration in a total of two directions using the remaining two sensors Xm and its vertical component Zm (= vibration acceleration calculated by differential calculation of the vibration acceleration at (az1-az2) / 2). When the output of the differential or sum calculation at any time t is x(t), the effective value of the vibration, RMS (Root Mean Square) calculation a(t), is given by the following equation 1.

number

[0029] The microcomputer in the wireless vibration monitoring system of this tool monitoring unit has an integration time of T = 0.1 s, performs analog calculations in real time, and after A / D conversion of the calculation result a(t), transmits it wirelessly at a transfer frequency of 50 Hz, i.e., at intervals of 0.02 s, from the small case to a receiver connected to a remote PC. The natural frequency of the sensor used here is 20 kHz, making it possible to detect vibration accelerations up to about 10 kHz.

[0030] Specifically, the vibration measurement signal flow from a piezoelectric accelerometer (4X acceleration sensor) is as shown in the left column of Figure 4. The piezoelectric accelerometer transmits an analog vibration signal, which is then matched by an amplifier to adjust the impedance and gain-to-frequency characteristics. The amplifier's output signal can be filtered to eliminate the piezoelectric accelerometer's resonant frequency. The output signal is then passed through a low-pass filter to a subtraction circuit (differential amplifier) ​​consisting of an operational amplifier, an adder, and an averaging circuit to quantitatively capture the magnitude of the vibration—for example, root-mean-square (RMS) averaging—and output the effective acceleration value. The analog signal is then converted to a digital signal by an A / D converter, and the data is processed by a microcontroller and transmitted externally via a wireless transmitter. Although not shown, the wirelessly transmitted vibration information (vibration data) is received by a wireless receiver and processed by an external PC with dedicated software installed, where it is displayed on the screen on the same time axis as the sensor information and CNC internal information from the collaborative robot, and is then analyzed, and the CNC internal information is corrected, etc., so that it can be interrupted and processed by the external PC to the robot's internal control unit.

[0031] <<Processing conditions>> As an example of a demonstration experiment, the force, temperature, and vibration were monitored when polishing the periphery of an octagonal workpiece made of JIS:S50C material. Figure 5 shows a schematic diagram of the workpiece shape, tool path, and sensing position, and Table 4 below shows the polishing conditions. The polishing operation consisted of three sets of 20 back and forth strokes, in which the four sides of the octagonal workpiece were polished continuously, and the surface roughness after processing was confirmed. Processing monitoring was carried out using the base force sensor, infrared temperature sensor, and wireless vibration measurement system mentioned above. This operation was carried out for two cutting conditions. [Table 4]

[0032] Results and Considerations of the Demonstration Experiment (Detection of CNC Internal Information and Forces of Collaborative Robots) The force was detected by applying pressure in the X, Y, and Z directions in an absolute coordinate system (hereinafter also referred to as the "robot coordinate system") based on the collaborative robot at points 1 and 2 (Pressure point 1 (Tool end), Pressure point 2 (Base)) shown in Figure 1 using a spring balance in increments of 0.98 N until the pressure reached 4.9 N (specifically, six conditions: 0 N, 0.98 N, 1.96 N, 2.94 N, 3.92 N, 4.9 N). The values ​​of the force sensors (Force sensor (Base), Force sensor (Hand)) were then confirmed when the pressure was reduced in the same increments to 0 N. In Figure 6, the left and right columns show the relationship between the pressure (horizontal axis) at points 1 and 2 (Pressure point 1 (Tool end), Pressure point 2 (Base)) in Figure 1 and the one-second average (vertical axis) of system variables 1-3 (upper to lower rows (Hand Force [1] to [3])) of the hand force sensor (Force sensor (Hand)). Similarly to Figure 6, the left and right columns show the relationship between the pressure (horizontal axis) at points 1 and 2 (Pressure point 1 (Tool end), Pressure point 2 (Base)) and the one-second average (horizontal axis) of system variables 1-3 (upper to lower rows (Base Force [1] to [3])) of the base force sensor (Force sensor (Base)).

[0033] As shown in the left column of Figure 6, at point 1 (Pressure point 1 (Tool end)) in Figure 1, system variable 1 (top row (Hand Force [1])) fluctuates significantly in the Z and X directions, while system variable 2 (middle row (Hand Force [2])) changes in the Y direction, and system variable 3 (bottom row (Hand Force [3])) fluctuates significantly in the X and Z directions. This is thought to be due to the tool attachment direction not being the same as the direction recognized by the hand force sensor (Force sensor (Hand)). This led to the prediction that the hand force sensor (Force sensor (Hand)) would not be able to recognize the load when it was applied to the base. In fact, as shown in the right column of Figure 6, at point 2 (Pressure point 2 (Base)), the base sensor (Force sensor (Base)) remained almost flat from the 0 point.

[0034] Next, as shown in the left column of Figure 7, at point 1 (Pressure point 1 (Tool end)) in Figure 1, system variable 1 (top row (Base Force [1])) changes linearly in the X direction, system variable 2 (middle row (Base Force [2])) changes linearly in the Y direction, and system variable 3 (bottom row (Base Force [3])) changes linearly in the Z direction when a load is applied. Furthermore, the relative change from 0 N load is almost the same regardless of the load application position, demonstrating that the load at the tip can be adequately recognized by the force sensor on the base (Force sensor (Base)). Therefore, the demonstration experiment demonstrated that when recognizing the load on a workpiece, the force sensor on the robot base (Force sensor (Base)), which can obtain data in the robot space coordinate system (absolute coordinates), is superior, and can also adequately obtain the load on the tool tip. By utilizing this, data based on relative coordinates from this tool monitoring unit, which senses the force of a tool, can be evaluated in the robot space coordinate system (absolute coordinates) on the same time axis.

[0035] <Monitoring the grinding wheel temperature> Figure 8 shows a photograph of the heat generated during polishing, taken with an infrared thermography camera (see also Figure 1) from point c (90°) in Figure 2. The surface temperature was found to be constant in the tool radial direction. This was true regardless of the photographing angle. Figure 9 is a graph showing that the temperature remained constant in the tool radial direction, not just when it saturated, but from the initial temperature rise. This graph plots the time-dependent change in maximum temperature within the measurement range at each angle: 30° (30°), 90° (90°), 150° (150°), and 180° (180°), while the time-dependent change in temperature obtained from the infrared temperature sensor (see also Figure 1) is plotted at 180°. Comparing these graphs, it can be seen that the graphs for both sensors are similar. This indicates that the temperature value for this grinding wheel does not change significantly depending on the measurement angle, and that measuring the temperature at one point in the radial direction during polishing is sufficient. Furthermore, there was no significant difference between the temperature values ​​obtained by the infrared thermography camera and the infrared temperature sensor, and it was found that the infrared temperature sensor can adequately measure the temperature during processing.

[0036] <<Force, temperature, and vibration monitoring when cutting depth changes>> Furthermore, in the above polishing process, the tool was rotated and pressed against the workpiece (S50C (carbon steel for machine structures)) in the Y-direction in the robot coordinate system as an absolute coordinate for 60 seconds, and the force, temperature, and vibration were monitored. The radial depth of cut was varied from 0 to 0.5 mm in 0.1 mm increments, and six conditions were tested. Figure 10 shows the change in the tool rotation speed (vertical axis: spindle speed (min)) at 10 seconds after pressing began. -1 )) plotted against the depth of cut (horizontal axis: Ae (mm)). This graph shows that as the depth of cut increases, the contact area between the tool and the workpiece increases, and the resulting friction force reduces the rotation speed of the tool.

[0037] In Figure 11, the upper left column shows the temperature value (Temperature (℃)) from the infrared temperature sensor (see also Figure 1), the middle left column shows Xm (the vibration acceleration obtained by calculating the difference in vibration acceleration using (ax1 - ax2) / 2 as shown in Figure 4: Vibration RMS (mV)), the lower left column shows Zm (the vibration acceleration of the vertical component of Xm obtained by calculating the difference in vibration acceleration using Zm = (az1 - az2) / 2 as shown in Figure 4: Vibration RMS (mV)), and the upper and lower right columns show the average values ​​calculated from the base force sensors (Base force [1] to [3] (see also Figure 4): Original data (-)) from 10 seconds to 50 seconds after the start of machining, which are plotted against the change in cutting depth (Ae (mm)). Checking the average values ​​of the infrared temperature sensor (top row in the left column) shows that the temperature rose with each increase in the cutting depth up to Ae = 0.3 mm, but as the cutting depth was increased further, the temperature dropped and a stable temperature equilibrium state was reached. This is thought to be because as the cutting depth was increased, the contact area between the tool and workpiece increased, the tool rotation speed decreased, and the amount of removal per unit time decreased. Also, checking the vibration values ​​(vibration acceleration) Xm and Zm showed that the cutting depth Ae = 0.2 mm was the highest, and as the cutting depth was increased further, the vibration value (vibration acceleration) decreased (bottom center row in the left column), which is thought to be due to the detection of a decrease in forced vibration due to a decrease in rotation speed and the effects of changes in contact rigidity.

[0038] When checking the values ​​of the base force sensor (Base force[1]~[2]) synchronized with the hand force sensor (Force sensor (Hand)) from the upper middle of the right column of Figure 11, it appears that a force equivalent to 1N in the X direction and 4N in the Y direction is generated when Ae = 0.5mm, and it was found that this increases exponentially according to the cutting depth (Ae). Furthermore, from the bottom right column of Figure 11, the force in the Z direction (value of the base force sensor (Base force[3])) is almost constant at cutting depths Ae of 0.1~0.5mm, and because it does not depend greatly on the cutting depth, it is possible to find the appropriate cutting depth that achieves temperature equilibrium and reduces vibration.

[0039] <<Results and Considerations of the Demonstration Experiment (Polishing with a Grinding Stone)>> Since stable polishing conditions were determined using wireless monitoring, we investigated the polishing efficiency at 20, 40, and 60 strokes when the depth of cut Ae was 0.2 mm and 0.4 mm, which have the largest difference. The average values ​​of the various monitoring results are shown in Figure 12, and the results of observing the surface properties are shown in Figure 13. When checking the surface roughness Ra value, it was found that the value was lower at Ae = 0.4 mm, where vibration was stable, resulting in a better surface and efficient polishing. Comparing the monitoring results for each depth of cut, it was found that the temperature and force were higher when the depth of cut was larger, and the vibration was smaller when the depth of cut was smaller. Although the grinding volume was larger and heat was generated at Ae = 0.4 mm, which is deeper than Ae = 0.2 mm, the reduced rotation speed and therefore reduced vibration are thought to be the reason for the reduced surface roughness.

[0040] Summary of the demonstration experiment A monitoring system with wireless communication capabilities as the tool monitoring unit in this industrial robot control system, a monitoring system with infrared wireless communication capabilities, and an infrared temperature sensor were attached to the collaborative robot, and polishing processing was verified while integrating this with the acquisition of internal CNC information of the collaborative robot. As a result, the following observations were made. (1) It was found that the machining load generated at the tip of the robot can be monitored by utilizing the internal CNC information from the force sensor on the base of the collaborative robot, which is used to detect contact (interference) with people and surrounding parts. (2) By using an infrared thermography camera, it was found that the machining temperature was uniform around the circumference of the grinding wheel, and that the temperature at the machining point could be measured by observing the temperature at one point around the tool. (3) When the cutting depth of the grinding wheel was changed, the rotation speed of the air grinder decreased according to the cutting depth, the temperature reached equilibrium, and the contact stiffness changed, stabilizing the vibration. Therefore, it was found that the appropriate cutting depth could be found by monitoring these factors. (4) A case study was carried out using the appropriate cutting depth determined through monitoring, and it was confirmed that this industrial robot control system is effective in improving machining.

[0041] <<Example of control using this industrial robot control system based on the results of monitoring and analysis>> In addition, in this industrial robot control system, the sensor information, CNC internal information of the collaborative robot, and force, vibration, and temperature information read by the tool monitoring unit in synchronization within the external computer 8 are compared and judged against pre-set conditions according to processing conditions such as polishing, and a signal is sent to interrupt the CNC internal information of the collaborative robot to correct or stop the operation of the collaborative robot, thereby changing the NC program.

[0042] Although not shown in the figure, a specific example of an interrupt processing flow on the NC program side of the collaborative robot's internal control unit is as follows: when the interrupt control function is turned on from an external PC, a subprogram is registered to be called as a correction or stop of the collaborative robot's operation when an interrupt occurs; when the collaborative robot's internal control unit (NC program) receives an interrupt signal from the external PC, the internal control unit executes the registered subprogram, which controls the collaborative robot to correct or stop its operation.

Claims

1. an industrial robot that is displaceable relative to a workpiece placed on a stage and performs predetermined processing on a non-processing target portion of the workpiece; a robot internal control unit that controls the posture and predetermined movement / rotation operations of the industrial robot; a displacement amount detection unit that successively detects the amount of displacement of the industrial robot relative to the workpiece during a predetermined processing; and an in-robot detection unit that detects a force generated by contact between at least a part, a workpiece, or an external object supported by the industrial robot and the industrial robot or a part supported by the industrial robot, The robot internal control unit an industrial robot system that performs force control based on a detection value of a detection unit in the robot while controlling the industrial robot using information on the posture of the industrial robot and a detection value of the displacement amount detection unit when the industrial robot performs the predetermined movement / rotation operation, A tool monitoring unit is connected to the tip of the industrial robot, which holds a processing tool that performs a predetermined processing on a portion to be processed of a workpiece and moves and / or rotates in cooperation with the industrial robot, and the tool monitoring unit comprises at least a processing tool detection unit that successively detects forces acting on the processing tool, and an interrupt control unit that corrects a control signal for a robot internal control unit of the industrial robot based on detection values ​​of the processing tool detection unit and the robot internal detection unit on the same time axis, The tool monitoring unit calculates the force detection value detected by the processing tool detection unit from the force detection value detected by the detection unit within the robot on the same time axis.

2. an industrial robot that is displaceable relative to a workpiece placed on a stage and performs predetermined processing on a non-processing target portion of the workpiece; a robot internal control unit that controls the posture and predetermined movement / rotation operations of the industrial robot; a displacement amount detection unit that successively detects the amount of displacement of the industrial robot relative to the workpiece during a predetermined processing; and an in-robot detection unit that detects a force generated by contact between at least a part, a workpiece, or an external object supported by the industrial robot and the industrial robot or a part supported by the industrial robot, The robot internal control unit an industrial robot system that performs force control based on a detection value of a detection unit in the robot while controlling the industrial robot using information on the posture of the industrial robot and a detection value of the displacement amount detection unit when the industrial robot performs the predetermined movement / rotation operation, A tool monitoring unit is connected to the tip of the industrial robot, which holds a processing tool that performs a predetermined processing on a portion to be processed of a workpiece and moves and / or rotates in cooperation with the industrial robot, and the tool monitoring unit comprises at least a processing tool detection unit that successively detects forces acting on the processing tool, and an interrupt control unit that corrects a control signal for a robot internal control unit of the industrial robot based on detection values ​​of the processing tool detection unit and the robot internal detection unit on the same time axis, the processing tool detection unit of the tool monitoring unit sequentially detects the force, vibration, and / or heat generated in the processing tool; The temperature successively detected by the processing tool detection unit is detected by at least one non-contact external thermometer arranged facing in the direction of any processing surface of the processing tool relative to the workpiece.

3. 3. The industrial robot control system according to claim 2, wherein the vibrations successively detected by the processing tool detection unit are detected by an acceleration sensor that detects vibration accelerations in translational and vertical directions of the processing tool relative to the workpiece.

4. 4. The industrial robot control system according to claim 1, wherein the tool monitoring unit compares the detection value of the machining tool detection unit, the detection value of the robot internal detection unit, and / or the detection value of the displacement amount detection unit on the same time axis, and corrects the control of the robot internal control unit using the interrupt control unit.

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