JP7804490B2 - Robot control device and robot system - Google Patents

Description

The present invention relates to a robot control device and a robot system.

In recent years, many robots have become widespread in industry. These robots are used, for example, for assembling, welding, and transporting electronic and mechanical parts, and for processing metals, castings, resins, and wood, thereby improving the efficiency and automation of manufacturing processes.

For example, a robot with a cutting tool attached as an end effector to the end of its arm is used to remove burrs from castings or cut weld beads. If the robot collides with the workpiece or a nearby obstacle, the cutting tool attached to the end of the arm and the robot itself will be damaged. For this reason, it is desirable to properly detect collisions between the robot and the workpiece or nearby obstacles and quickly stop the robot.

Patent Document 1 discloses technology related to a robot control device that detects when a robot collides with a surrounding object without using additional sensors and prevents damage to the robot or the surrounding object. The robot control device described in Patent Document 1 calculates the drive torque required for the task to be performed by the robot, such as deburring or hand opening and closing, and determines whether a collision has occurred based on this drive torque and the current of the motors that drive each joint.

Patent document 2 also discloses technology related to a robot collision detection device that is equipped with a force sensor in the robot's hand to detect impact forces and determines collisions based on the magnitude of the detected impact forces.

Japanese Patent Application Laid-Open No. 2003-25272 Japanese Patent Application Publication No. 4-19093

However, with the robot control device described in Patent Document 1, for example, when attempting to detect a collision during cutting, it is necessary to distinguish this from impacts during cutting, and therefore the threshold for determining that a collision has been detected must be set high. This results in a delay in detecting the collision, making it impossible to quickly stop the robot. As a result, there is a risk of damage to the cutting tool, robot, etc.

It is also possible to equip the robot with force sensors to quickly grasp the situation, as in the robot collision detection device described in Patent Document 2, but in order to properly detect collisions between the robot and obstacles, etc., multiple force sensors would be required, which would increase costs.

The present invention aims to provide a robot control device and robot system that can grasp the situation based on the load on a tool attached to the robot's arm and appropriately detect collisions.

A robot control device according to one aspect of the present invention controls the operation of a robot and includes a torque monitoring unit that monitors the torque applied to the robot, a load calculation unit that calculates the load applied to a spindle motor that drives a tool attached to the robot's arm, a collision detection threshold setting unit that sets a collision detection threshold according to the load applied to the spindle motor, and a collision determination unit that determines whether the robot will collide based on at least the monitored torque and the set collision detection threshold.

According to this aspect, the load calculation unit grasps the situation by calculating the load on the spindle motor that drives the tool attached to the robot's arm, and the collision detection threshold setting unit sets a collision detection threshold according to the load on the spindle motor. The collision determination unit then determines a robot collision based on at least the monitored torque and the set collision detection threshold. As a result, it is possible to properly detect a robot collision and quickly stop the robot, thereby reducing and preventing damage to the cutting tool attached to the arm, the robot, etc.

In the above aspect, the collision detection threshold setting unit may set the collision detection threshold depending on whether or not work is being performed while the tool is in contact with the workpiece.

In this aspect, the collision detection threshold setting unit sets the collision detection threshold depending on whether or not work is being performed while the tool is in contact with the workpiece. This allows for appropriate detection of robot collisions both during and outside of work, taking into account the load on the tool during work.

In the above aspect, the collision detection threshold setting unit may set one of a first threshold corresponding to a non-working state in which the tool is not in contact with the workpiece, a second threshold corresponding to a working state, and a threshold corresponding to the load rate on the spindle motor.

In this aspect, the collision detection threshold setting unit sets one of a first threshold corresponding to non-working conditions, a second threshold corresponding to working conditions, and a threshold corresponding to the load rate, thereby taking into more detailed consideration the load on the tool during work and more appropriately detecting robot collisions during work and non-working conditions.

In the above aspect, the load calculation unit may calculate the load on the spindle motor based on loads on multiple spindle motors sampled over a predetermined period, and the collision detection threshold setting unit may set a collision detection threshold according to the calculated load on the spindle motor.

In this aspect, the load calculation unit calculates the load on the spindle motor based on the loads on multiple spindle motors sampled over a predetermined period, allowing for an appropriate understanding of the situation. The collision detection threshold setting unit then sets an appropriate collision detection threshold in accordance with the calculated load on the spindle motor, allowing for more appropriate detection of robot collisions.

A robot system according to one aspect of the present invention includes a spindle motor that drives a tool attached to the arm of the robot, a spindle motor control device that controls the spindle motor, and a robot control device that controls the operation of the robot and issues operation instructions to the spindle motor control device. The robot control device includes a torque monitoring unit that monitors the torque applied to the robot, a load calculation unit that calculates the load applied to the spindle motor, a collision detection threshold setting unit that sets a collision detection threshold according to the load applied to the spindle motor, and a collision determination unit that determines whether the robot will collide based on at least the monitored torque and the set collision detection threshold.

In this aspect, in the robot control device, the load calculation unit grasps the situation by calculating the load on the spindle motor that drives the tool attached to the robot's arm, and the collision detection threshold setting unit sets a collision detection threshold according to the load on the spindle motor. The collision determination unit then determines a robot collision based on at least the monitored torque and the set collision detection threshold. As a result, it is possible to properly detect a robot collision and quickly stop the robot, thereby reducing and preventing damage to the cutting tool attached to the arm, the robot, etc.

The present invention provides a robot control device and robot system that can grasp the situation based on the load on a tool attached to the robot's arm and appropriately detect collisions.

1 is a configuration diagram showing an overview of a robot system 10 according to an embodiment of the present invention. FIG. 1 is a functional block diagram showing each function of a robot system 10 according to an embodiment of the present invention. FIG. 10 is a diagram showing a specific example of a current waveform related to a load applied to a spindle motor during cutting work. FIG. 10 is a diagram showing a specific example of a collision detection threshold that is set according to a load applied to a spindle motor. FIG. 10 is a diagram showing a specific example of timing at which a collision detection threshold is set in accordance with a load applied to a spindle motor. 1 is a flowchart showing a robot collision detection method M100 executed by a robot controller 100 included in a robot system 10 according to an embodiment of the present invention. FIG. 10 is a diagram showing another specific example of the timing at which the collision detection threshold is set in accordance with the load applied to the spindle motor.

Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings. Note that the embodiment described below is merely a specific example for implementing the present invention and is not intended to limit the scope of the present invention. Furthermore, to facilitate understanding of the description, identical components in each drawing will be designated by the same reference numerals wherever possible, and duplicate descriptions may be omitted.

<One embodiment>
[Robot system configuration]
1 is a configuration diagram showing an overview of a robot system 10 according to an embodiment of the present invention. As shown in FIG. 1, the robot system 10 includes a robot 20, a cutting tool 30, a spindle motor 31, a spindle motor control device 32, and a robot control device 100.

The robot 20 is an industrial robot equipped with a cutting tool 30 attached as an end effector to the tip of its arm, and is used, for example, to remove burrs from castings or cut weld beads. Based on operational instructions from the robot control device 100, the robot 20 rotates each axis using multiple servo motors 21 to move and rotate the arm, thereby moving the cutting tool 30 to an appropriate position and angle.

The cutting tool 30 includes, for example, an end mill or face milling cutter, and is driven by a spindle motor 31 to remove burrs from castings or cut weld beads.

The spindle motor 31 is controlled by the spindle motor control device 32 and drives the cutting tool 30.

The spindle motor control device 32 controls the spindle motor 31 so that it rotates based on the rotation speed, rotation time, etc. commanded by the rotation start command from the robot control device 100. The spindle motor control device 32 also notifies the robot control device 100 of the current value during rotation of the spindle motor 31 as the load applied to the spindle motor 31.

The robot controller 100 controls the operation of the robot 20. Specifically, the robot controller 100 controls the multiple servo motors 21 in the robot 20 to rotate each axis and move and rotate the arm. In this way, the robot controller 100 controls the robot 20 to maintain an appropriate position and posture.

As described above, the robot control device 100 also controls the operation of the cutting tool 30 attached to the tip of the arm of the robot 20 by instructing the spindle motor control device 32 to rotate the spindle motor 31.

Furthermore, if the robot control device 100 detects a collision of the robot 20, it controls the robot 20 and cutting tool 30 to stop.

[Robot collision detection]
The function of detecting a collision of the robot 20 will be described in detail below.
2 is a functional block diagram showing each function of the robot system 10 according to one embodiment of the present invention. As shown in FIG. 2, the robot control device 100 that controls the operation of the robot 20 includes a servo motor control unit 110, a torque monitoring unit 120, a load calculation unit 130, a collision detection threshold setting unit 140, a collision determination unit 150, and a storage unit 160.

The servo motor control unit 110 controls multiple servo motors 21 that rotate each axis of the robot 20 so as to move and rotate the arms of the robot 20. Specifically, the servo motor control unit 110 sends commands, including the required output (electrical power), on how to drive the multiple servo motors 21 (position, speed, rotational force, etc.) so that the position and orientation of the robot 20 becomes the desired position and angle. The multiple servo motors 21 are driven based on commands from the servo motor control unit 110, but how they were actually driven is determined by detecting information such as the position, speed, and rotational force of the multiple servo motors 21 using an encoder.

The torque monitoring unit 120 monitors the torque applied to the robot 20. Specifically, the torque monitoring unit 120 monitors the torque applied to the robot 20 based on information from the multiple servo motors 21 detected by the encoders described above. In other words, the torque monitoring unit 120 monitors the torque applied to the robot 20 based on how the multiple servo motors 21 are actually driven (position, speed, rotational force, etc.), and grasps the situation of the robot 20, including its position and posture.

The load calculation unit 130 calculates the load on the spindle motor 31 that drives the cutting tool 30 attached to the arm of the robot 20. Specifically, the load calculation unit 130 acquires the current value during rotation of the spindle motor 31 as the load on the spindle motor 31 via the spindle motor control device 32. For example, if the robot 20 is cutting (operating) a workpiece such as a casting, the load calculation unit 130 acquires a current value corresponding to the rotation speed of the spindle motor 31, etc. If cutting is not in progress, the spindle motor 31 is stopped and therefore acquires 0 or a small current value (such as standby current).

The collision detection threshold setting unit 140 sets a collision detection threshold according to the load on the spindle motor 31 calculated by the load calculation unit 130. For example, the torque applied to the robot 20 depends on the position, posture, and movement of the robot 20. Normally, when there is no collision of the robot 20, the torque applied to the robot 20 can be calculated based on the position, posture, and other factors of the robot 20, including the rotation angles of each axis and the position and inclination of the arms, and its value can be estimated (estimated torque). On the other hand, when the robot 20 collides with an obstacle, the torque actually applied to the robot 20 will be greater than the estimated torque when there is no collision of the robot 20 as described above.

Here, by appropriately setting a collision detection threshold that can be used to determine that a collision of the robot 20 has been detected, it is possible to detect that the robot 20 has collided with an obstacle or the like by comparing the torque applied to the robot 20 with the set collision detection threshold. Furthermore, it may be determined that a collision of the robot 20 has been detected when there is a large difference between the torque actually applied to the robot 20 and the estimated torque in the absence of a collision of the robot 20 described above. When determining that a collision of the robot 20 has been detected in this way, it is sufficient to set a collision detection threshold that corresponds to this difference.

However, the torque applied to the robot 20 is greater when the robot 20 is cutting a workpiece such as a casting than when it is not cutting, so it is necessary to appropriately set the collision detection threshold for determining whether the robot 20 has detected a collision depending on whether cutting is in progress.

In other words, the collision detection threshold setting unit 140 sets the collision detection threshold depending on whether cutting is in progress. For example, the collision detection threshold setting unit 140 determines whether cutting is in progress based on the load on the spindle motor 31 calculated by the load calculation unit 130, and sets the collision detection threshold according to this determination.

Figure 3 shows a specific example of a current waveform related to the load on the spindle motor during cutting work. As shown in Figure 3, the current value of the spindle motor 31 rises sharply, reaches a maximum at point S, fluctuates while maintaining a high current level, and then drops sharply to a minimum at point E.

In other words, when the current value of the spindle motor 31 rises sharply and fluctuates while maintaining a high level, cutting is in progress, and when the current value remains stable near zero, cutting is not in progress.

Here, the collision detection threshold setting unit 140 determines whether cutting is in progress based on the load on the spindle motor 31 calculated by the load calculation unit 130, and sets a collision detection threshold according to this determination. For example, the collision detection threshold corresponding to non-cutting times may be set as a first threshold, and the collision detection threshold corresponding to cutting times may be set as a second threshold (first threshold < second threshold), and appropriate collision detection thresholds may be stored in advance in the storage unit 160.

In addition, cutting work may be actually performed by the robot 20, and the torque monitoring unit 120 may collect the torque applied to the robot 20 corresponding to the load on the spindle motor 31 during cutting and non-cutting. An appropriate collision detection threshold may then be stored in the memory unit 160 based on the collected torque applied to the robot 20. For example, the maximum and minimum loads applied to the spindle motor 31 during cutting and a collision detection threshold (second threshold) based on the torque applied to the robot 20 may be stored in the memory unit 160. In addition, a collision detection threshold (first threshold) based on the torque applied to the robot 20 during non-cutting may be stored in the memory unit 160.

The first and second thresholds are set according to conditions such as the material of the workpiece to be cut, the cutting position, and the type of robot 20 and cutting tool 30, so the memory unit 160 may be updated when these conditions change. Specifically, when cutting a different type of workpiece, the torque applied to the robot 20 can be collected by the torque monitoring unit 120 the first time and an appropriate collision detection threshold (first and second thresholds) can be calculated.

Furthermore, for example, during cutting, the load on the spindle motor 31 may differ or fluctuate depending on the cutting position, angle, cutting amount, timing, etc., and this load also affects the torque applied to the robot 20. For this reason, during cutting, it is preferable to set the collision detection threshold based on the torque applied to the robot 20 in more detail depending on the load on the spindle motor 31.

As described above, the collision detection threshold setting unit 140 sets, for example, a first threshold that is a collision detection threshold corresponding to a non-cutting state, and a second threshold that is a collision detection threshold corresponding to a cutting state (first threshold < second threshold), and further sets a threshold according to the load rate applied to the spindle motor 31. Here, the first threshold is a collision detection threshold corresponding to a non-cutting state and is the lower limit of the thresholds for detecting a collision of the robot 20, and the second threshold is a collision detection threshold corresponding to a cutting state and is the upper limit of the thresholds for detecting a collision of the robot 20. The threshold according to the load rate applied to the spindle motor 31 may be calculated using the following (Equation 1).
Threshold value according to the load factor applied to the spindle motor 31=(second threshold value−first threshold value)×load factor+first threshold value (Equation 1)

Furthermore, the load rate applied to the spindle motor 31 may be calculated, for example, by dividing the period from when the spindle motor 31 starts to rotate until when it stops rotating into a plurality of intervals in units of a predetermined period, and using the following equation (2) based on the load applied to the spindle motor 31 in each interval (e.g., maximum load and minimum load) and the specified value of the spindle motor 31 (e.g., maximum load and minimum load allowed as product specifications).
Load factor applied to spindle motor 31=(difference between maximum load and minimum load in a predetermined period)/(difference between predetermined maximum load and minimum load) (Equation 2)

The system is divided into multiple intervals in predetermined time periods, and the load on the spindle motor 31 in each interval (e.g., maximum load, minimum load, etc.) is stored in a storage unit such as a memory as past performance data, and is used when calculating the load rate on the spindle motor 31.

Figure 4 shows a specific example of a collision detection threshold that is set according to the load on the spindle motor. As shown in Figure 4, the collision detection threshold setting unit 140 sets the collision detection threshold to a first threshold (lower limit threshold) when not cutting, a second threshold (upper limit threshold) when the load rate calculated using the above (Equation 2) is 90% or greater, and a threshold according to the load rate on the spindle motor 31 calculated using the above (Equation 1) when the load rate is 10% or greater but less than 90%.

Note that, since the load rate on the spindle motor 31 is assumed to be in 10% increments and the result calculated using the above (Equation 2) is rounded up, the collision detection threshold setting unit 140 sets the threshold calculated using a load rate of 10% as the collision detection threshold when the load rate is less than 10%. This prevents the collision detection threshold from changing frequently and finely, simplifying the calculation and judgment processes, but is not limited to 10% increments. For example, if the change in torque applied to the robot 20 when it collides is minute, the result calculated using the above (Equation 2) can be validated in increments smaller than 10%, and can be set appropriately depending on the required accuracy, etc.

Figure 5 shows a specific example of the timing at which the collision detection threshold is set depending on the load on the spindle motor. As shown in Figure 5, the collision detection threshold is set depending on the load on the spindle motor 31, and a collision of the robot 20 is determined depending on whether the difference between the actual torque and estimated torque applied to the robot 20 exceeds the collision detection threshold.

Specifically, the load calculation unit 130 calculates the load on the spindle motor 31 based on the loads on the multiple spindle motors 31 sampled during each predetermined period T. By extracting the maximum and minimum loads from the loads on the multiple spindle motors 31 sampled during each predetermined period T, the load on the spindle motor 31 during each predetermined period T is calculated using the above equation (2). The collision detection threshold setting unit 140 then sets the collision detection threshold for each predetermined period T using the above equation (1) based on the load on the spindle motor 31 during each predetermined period T calculated by the load calculation unit 130. In other words, the collision detection threshold is set (updated) for each predetermined period T.

As shown in Figure 3, the load on the spindle motor 31 fluctuates rapidly during cutting. Therefore, if the collision detection threshold is set to follow this, the calculation and judgment processes related to collision detection by the robot 20 may become complicated, or the collision detection threshold may fluctuate rapidly, making it possible for a collision to be detected improperly. For this reason, as described above, it is preferable for the load calculation unit 130 to set the collision detection threshold at an appropriate timing (every predetermined period T) by calculating the load on the spindle motor 31 based on the loads on multiple spindle motors 31 sampled during each predetermined period T. Note that the predetermined period T may be set taking into account fluctuations in the load on the spindle motor 31, etc.

[Robot collision detection method]
Next, a method for detecting a collision of the robot will be specifically described in detail.

FIG. 6 is a flowchart showing a robot collision detection method M100 executed by a robot controller 100 included in a robot system 10 according to one embodiment of the present invention. As shown in FIG. 6, the robot collision detection method M100 includes steps S110 to S180, and each step is executed by a processor included in the robot controller 100.

In step S110, the robot control device 100 determines whether the robot is currently cutting. As a specific example, the collision detection threshold setting unit 140 determines whether the robot is currently cutting based on the load on the spindle motor 31 calculated by the load calculation unit 130.

If it is determined in step S110 that cutting is not in progress, the robot controller 100 sets the collision detection threshold to the first threshold (lower limit threshold) (step S120).

If it is determined in step S110 that cutting is in progress, the robot control device 100 calculates the load factor on the spindle motor (step S130). As a specific example, the collision detection threshold setting unit 140 may use the above-mentioned (Equation 2) to calculate this based on the maximum and minimum loads of the spindle motor 31 in each section from when the spindle motor 31 starts to when it stops rotating, and the maximum and minimum loads, etc., that are specified values for the spindle motor 31.

In step S140, the robot control device 100 determines the load factor calculated in step S130.

If it is determined in step S140 that the load rate is 90% or higher, the robot controller 100 sets the collision detection threshold to a second threshold (upper limit threshold) (step S150).

If it is determined in step S140 that the load rate is less than 90%, the robot control device 100 sets the collision detection threshold to a threshold value corresponding to the load rate calculated in step S130 (step S160). As a specific example, the collision detection threshold setting unit 140 may set the collision detection threshold to a threshold value calculated using the above-mentioned (Equation 1).

In step S170, the robot control device 100 determines the difference between the actual torque applied to the robot and the estimated torque. As a specific example, the collision determination unit 150 compares the difference between the torque actually applied to the robot 20 (actual torque) monitored by the torque monitoring unit 120 and the torque applied to the robot 20 (estimated torque) calculated based on the position and posture of the robot 20 when there is no collision of the robot 20, with the collision detection threshold set in step S120, S150, or S160.

If it is determined in step S170 that the difference is less than the collision detection threshold, the robot control device 100 returns to the processing of step S110. Specifically, the collision determination unit 150 determines that a collision of the robot 20 has not been detected.

If it is determined in step S170 that the difference is equal to or greater than the collision detection threshold, the robot control device 100 determines that a robot collision has been detected (step S180). Specifically, the collision determination unit 150 detects that the robot 20 has collided with an obstacle or the like. The robot control device 100 then controls the robot 20 and cutting tool 30 to stop.

As described above, according to the robot control device 100, robot system 10, and robot collision detection method M100 according to one embodiment of the present invention, the load calculation unit 130 grasps the situation by calculating the load on the spindle motor 31 that drives the cutting tool 30 attached to the arm of the robot 20, and the collision detection threshold setting unit 140 sets a collision detection threshold according to the load on the spindle motor 31. The collision determination unit 150 then determines a collision of the robot 20 based on at least the torque applied to the monitored robot 20 and the collision detection threshold set by the collision detection threshold setting unit 140. As a result, a collision of the robot 20 can be appropriately detected and the robot 20 can be quickly stopped, thereby reducing and preventing damage to the cutting tool 30 attached to the arm, the robot, etc.

In this embodiment, as explained using FIG. 5, the collision detection threshold is set (updated) every predetermined period T, but it is also possible to take into account the load on the spindle motor 31 detected in real time. As described above, the predetermined period T can be set as appropriate, but when the load on the spindle motor 31 is sampled during the predetermined period T and the load rate and collision detection threshold for that predetermined period T are calculated, a time lag may occur before the collision detection threshold calculated for every predetermined period T is set (updated). For this reason, the load rate and collision detection threshold are calculated taking into account the load on the spindle motor 31 detected in real time so that the collision detection threshold is more appropriate for the current situation.

Figure 7 shows another specific example of the timing at which the collision detection threshold is set depending on the load on the spindle motor. As shown in Figure 7, the collision detection threshold is set to reflect the load on the spindle motor 31.

Specifically, the load factor applied to the spindle motor 31 is calculated by dividing the period from when the spindle motor 31 starts to rotate until when it stops into a plurality of intervals in predetermined units, and taking into consideration the load applied to the spindle motor 31 in each interval (e.g., maximum load, minimum load, etc.) and the load detected in real time on the spindle motor 31. Then, similar to the above-mentioned (Equation 2), the load factor can be calculated using the following (Equation 3) based on the specified values of the spindle motor 31 (e.g., maximum load, minimum load, etc. allowed as product specifications).
Load factor applied to spindle motor 31={(two loads in a predetermined period)/2 and the difference between the minimum load in the predetermined period}/(difference between a predetermined maximum load and a predetermined minimum load) (Equation 3)

The two loads in a specified period may include, for example, two consecutive loads among the loads applied to the spindle motor 31 acquired in multiple sections of the specified period, as well as the current load and the load t seconds before or immediately before the present.

In this way, by taking into account the load on the spindle motor 31 detected in real time, a collision detection threshold that reflects the load on the spindle motor 31 can be set, making it possible to more accurately grasp the current situation. As a result, the collision detection threshold can be set more appropriately, and collisions of the robot 20 can be more accurately detected.

In this embodiment, the robot 20 has been described as removing burrs from castings or cutting weld beads, using a cutting tool 30 as an example of an end effector attached to the arm of the robot 20, but this is not limited to this. For example, the present invention may be applied to drilling, chamfering, emindling (a type of cutting), polishing, reaming (finishing holes), cutting, etc., by attaching an appropriate tool as an end effector to the arm of the robot 20.

The embodiments described above are intended to facilitate understanding of the present invention and are not intended to limit the scope of the present invention. The elements included in the embodiments, as well as their arrangement, materials, conditions, shape, size, etc., are not limited to those illustrated and can be modified as appropriate. Furthermore, configurations shown in different embodiments can be partially substituted or combined.

10...Robot system, 20...Robot, 21...Servo motor, 30...Cutting tool, 31...Spindle motor, 32...Spindle motor control device, 100...Robot control device, 110...Servo motor control unit, 120...Torque monitoring unit, 130...Load calculation unit, 140...Collision detection threshold setting unit, 150...Collision determination unit, 160...Memory unit, M100...Robot collision detection method, S110-S180...Steps of robot collision detection method M100

Claims (3)

A robot control device for controlling the operation of a robot,
a torque monitoring unit that monitors a torque applied to the robot;
a load calculation unit that calculates a load applied to a spindle motor that drives a tool attached to an arm of the robot based on a plurality of loads applied to the spindle motor sampled over a predetermined period ;
a collision detection threshold setting unit that sets a collision detection threshold according to the load applied to the spindle motor calculated by the load calculation unit ;
a collision determination unit that determines a collision of the robot based on at least the monitored torque and the set collision detection threshold ,
the collision detection threshold setting unit sets one of a first threshold corresponding to a non-working state in which the tool is not in contact with a workpiece, a second threshold corresponding to the work being performed, and a threshold corresponding to a load rate applied to the spindle motor.
Robot control device. the collision detection threshold setting unit sets the collision detection threshold depending on whether or not the tool is in contact with a workpiece during an operation.
The robot control device according to claim 1 . a spindle motor that drives a tool attached to the arm of the robot;
a spindle motor control device that controls the spindle motor;
a robot control device that controls the operation of the robot and instructs the spindle motor control device to operate;
The robot control device
a torque monitoring unit that monitors a torque applied to the robot;
a load calculation unit that calculates a load applied to the spindle motor based on a plurality of loads applied to the spindle motor sampled over a predetermined period ;
a collision detection threshold setting unit that sets a collision detection threshold according to the load applied to the spindle motor calculated by the load calculation unit ;
a collision determination unit that determines a collision of the robot based on at least the monitored torque and the set collision detection threshold ,
the collision detection threshold setting unit sets one of a first threshold corresponding to a non-working state in which the tool is not in contact with a workpiece, a second threshold corresponding to the work being performed, and a threshold corresponding to a load rate applied to the spindle motor.
Robot system.