A method for detecting abnormality of brakes of multi-joint robots

Abstract

The present invention relates to a method for detecting abnormality of brakes of a multi-joint robot, which is characterized in that a multi-joint robot comprises a mechanical arm and a plurality of joints, wherein the joints comprise: a housing; a motor; a brake, wherein the brake comprises: a brake pad, which is sleeved on a motor shaft to rotate with the motor shaft; a stopper, wherein the stopper comprises an extended state and a retracted state, wherein the stopper can contact the brake pad when in the extended state to at least partially limit the rotation of the brake pad; the multi-joint robot comprises: a detection module, which is used to detect whether there is an abnormality in the brake before the robot is powered on and starts to perform work and / or before the robot is powered off after the work is completed, and when the motor is in an excitation state; and a control module, which is used to maintain the motor excitation state and output an abnormal instruction according to the detection of abnormality in the brake. The beneficial effects of the present invention are that the braking reliability and safety of the multi-joint robot are good.

Description

Technical Field

[0001] The present invention relates to the field of industrial robots, and in particular to a multi-joint robot and a control method thereof. Background Art

[0002] With the development of society, robots have begun to be widely used in many fields such as household robots, industrial robots, and service robots. Industrial robots include mechanical arms and multiple joints, which are often used to replace or assist human work in industrial environments. Industrial robots include traditional industrial robots and new collaborative robots. Collaborative robots are often used to work with people. Therefore, collaborative robots are a type of robot with higher safety requirements among industrial robots. The joints of industrial robots include brakes and motors, where the motor provides the driving force for the joints, and the brake is used to limit the rotation of the motor to stop the movement of the corresponding joints. For industrial robots, especially for collaborative robots, the performance of the brake is very important. If the brake is abnormal, the robot may be in danger of hitting the arm or falling.

[0003] CN109760035A discloses a robot modular joint redundant brake device, which adopts a redundant braking design of a first gear lever and a second gear lever, and detects resistance values ​​through a first pressure sensor and a second pressure sensor respectively to determine whether the gear lever is braked in place, and uses a normally open brake component to ensure that the arm is not hit, but the structural design is complex, difficult to implement, and the cost is high.

[0004] Therefore, it is necessary to design a multi-joint robot and its detection method with good braking performance, good reliability and easy implementation. Summary of the invention

[0005] In view of this, an object of the present invention is to provide a multi-joint robot and a detection method thereof with good braking performance, good reliability and easy implementation.

[0006] The present invention can adopt the following technical scheme: a multi-joint robot, including a mechanical arm and a plurality of joints, the joints including: a shell; a motor; a brake, the brake including: a brake pad, which is sleeved on the motor shaft to rotate with the motor shaft; a baffle, the baffle including an extended state and a retracted state, and the baffle can contact the brake pad when in the extended state to at least partially limit the rotation of the brake pad; the multi-joint robot includes: a detection module, which is used to detect whether there is an abnormality in the brake before the robot is powered on to start working and / or before the robot ends working and is powered off, and when the motor is in an excitation state; a control module, which is used to maintain the motor excitation state and output an abnormal instruction based on the detection of the abnormality of the brake.

[0007] Furthermore, the control module is used to detect that there is an abnormality in the brake and control the brake not to release the brake.

[0008] Furthermore, the abnormal instruction includes at least one of: a warning instruction, an instruction to reduce the working speed of the robot, an instruction to remind the user to process, and an instruction to remind the user to select a working mode.

[0009] Further, the detecting whether there is an abnormality in the brake includes: detecting whether the lever contacts the brake pad; and the detecting whether there is an abnormality in the brake includes: not detecting that the lever contacts the brake pad.

[0010] Further, the detecting whether there is an abnormality in the brake includes: detecting the movement amount of the motor within a predetermined time, and determining whether the movement amount exceeds a preset value; the detecting whether there is an abnormality in the brake includes: detecting that the movement amount exceeds a preset value.

[0011] Furthermore, the starting point of the predetermined time is when the barrier rod contacts the brake pad.

[0012] Furthermore, the detection module includes at least two position sensors, and the at least two position sensors are respectively used to detect the movement amount of the motor within a predetermined time, and only when the detection results are consistent, it is determined whether the movement amount exceeds a preset value.

[0013] Furthermore, the at least two position sensors include at least one of a joint encoder, a velocity / acceleration sensor, and a Hall sensor.

[0014] Furthermore, the control module is used to control the robot to power off or control the robot to release the brake to perform work according to detecting that the brake is normal.

[0015] The present invention can also adopt the following technical scheme: a detection method for a multi-joint robot, applied to the multi-joint robot described in any of the above items, the method comprising: before the robot is powered on to start working and / or before the robot finishes working and is powered off, and when the motor is in an excitation state, detecting whether there is an abnormality with the brake; if an abnormality is detected in the brake, maintaining the motor excitation state, and outputting an abnormal instruction.

[0016] Furthermore, the method includes: when an abnormality of the brake is detected, controlling the brake not to release the brake.

[0017] Furthermore, the abnormal instruction includes at least one of: a warning instruction, an instruction to reduce the working speed of the robot, an instruction to remind the user to process, and an instruction to remind the user to select a working mode.

[0018] Further, the detecting whether there is an abnormality in the brake includes: whether the lever contacts the brake pad; and the detecting whether there is an abnormality in the brake includes: not detecting that the lever contacts the brake pad.

[0019] Further, the detecting whether there is an abnormality in the brake includes: detecting the movement amount of the motor within a predetermined time, and determining whether the movement amount exceeds a preset value; the detecting whether there is an abnormality in the brake includes: detecting that the movement amount exceeds a preset value.

[0020] Further, the detecting whether there is an abnormality in the brake includes: detecting whether there is an abnormality in the brake by at least two position sensors respectively; the detecting whether there is an abnormality in the brake includes: when the results of the at least two position detectors are consistent, judging whether there is an abnormality in the brake.

[0021] Furthermore, the at least two position sensors include at least one of a joint encoder, a velocity / acceleration sensor, and a Hall sensor.

[0022] Compared with the prior art, the beneficial effects of the specific embodiments of the present invention are as follows: the multi-joint robot includes a lever-type brake, which confirms the working performance of the brake during the power-on and / or power-off stages of the multi-joint robot, thereby ensuring the braking performance during the operation of the robot. At the same time, the motor excitation is maintained when the braking performance is detected, so that the robot will not lose control and fall or smash its arm when the brake is abnormal. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The above-mentioned objectives, technical solutions and beneficial effects of the present invention can be achieved through the following drawings:

[0024] Figure 1 Schematic diagram of a multi-joint robot according to an embodiment of the present invention

[0025] Figure 2 Schematic diagram of a brake according to an embodiment of the present invention

[0026] Figure 3 An exploded view of a joint of an embodiment of the present invention

[0027] Figure 4a This is the time diagram of the industrial robot's motion start program

[0028] Figure 4b This is a time chart of the motion start program of the multi-joint robot according to one embodiment of the present invention.

[0029] Figure 5a This is the time diagram of the industrial robot stopping program

[0030] Figure 5b This is a time chart of the stop program of the multi-joint robot according to one embodiment of the present invention. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical scheme and advantages of the present invention clearer, the scheme in the embodiment of the present invention will be described clearly and completely in conjunction with the drawings in the embodiment of the present invention. Obviously, the described embodiment is a part of the embodiment of the present invention but not all of the embodiments. Based on the embodiment of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] The present invention protects a multi-joint robot, Figure 1 , Figure 1 1 is a schematic diagram of a multi-joint robot according to an embodiment of the present invention. The multi-joint robot includes a plurality of joints 130, for example, three, five, or six joints. Multi-joint robots with different numbers of joints have different degrees of freedom. A collaborative robot is a typical multi-joint robot. Figure 1 The multi-joint robot shown in the figure is a six-joint collaborative robot. The multi-joint robot protected by the present invention comprises a mechanical arm 120 and a plurality of joints. The mechanical arm 120 comprises a plurality of mechanical arm parts. The joints are used to connect adjacent mechanical arm parts. The joints 130 comprise: a housing 1; a motor 2; and a brake 10. The multi-joint robot 100 can be connected to a tool 200 to perform a work task. Figure 2 , Figure 2 A schematic diagram of a brake 10 of a multi-joint robot 100 according to an embodiment of the present invention is shown, wherein the brake 10 comprises: a brake pad 11, which is sleeved on a motor shaft 14 to rotate with the motor shaft 14; a stopper 12, wherein the stopper 12 comprises an extended state and a retracted state, wherein the stopper 12 can contact the brake pad 11 when in the extended state to at least partially restrict the rotation of the brake pad 11, and further, the brake 10 comprises an electromagnetic valve 13, wherein the electromagnetic valve 13 can control the switch of the stopper 12 between the extended state and the retracted state. The multi-joint robot 100 comprises a detection module, which is used to detect whether the brake 10 is abnormal before the robot is powered on to perform work and / or before the robot is powered off after finishing the work, and when the motor 2 is in the excitation state; and a control module, which is used to maintain the motor excitation state and output an abnormal instruction according to the detection of the abnormality of the brake 10. Specifically, the multi-joint robot 100 protected by the present invention adopts the above-mentioned lever-type brake, which includes a lever 12 and a brake plate 11. When the lever is in an extended state and contacts the brake plate 11, the rotation of the brake plate 11 can be at least partially restricted. Figure 3 , Figure 3An exploded diagram of a joint of a robot according to an embodiment of the present invention is shown, wherein the brake 10 further comprises brake pads 15 arranged on both sides of the brake pad 11, wherein the brake pads 15 can clamp the brake pad 11 during braking, so as to further realize power-on braking of the brake 10. In one embodiment of the present invention, specifically, after the robot is powered on, the brake 10 is released, and then the work task is started. In this embodiment, before the robot is powered on and starts to work, and the motor is in an excitation state, the detection module detects whether there is an abnormality in the brake 10, and when the control module detects that the brake 10 is abnormal, the motor is kept in an excitation state, and an abnormal instruction is outputted at the same time. In another embodiment of the present invention, similarly, after the robot finishes working, the brake 10 is braked, and then powered off and stopped. In this embodiment, after the robot finishes working, the brake is braked, and when the motor is in an excitation state, the detection module detects whether there is an abnormality in the brake 10, and when the control module detects that the brake 10 is abnormal, the motor is kept in an excitation state, and an abnormal instruction is outputted. The lever-type brake has idle motion during the braking process, that is, the movement process in which the brake pad 11 does not contact the lever during braking. When the motor is in the excitation state, it is detected whether the brake is abnormal. Then, the motor in the excitation state can be in a rotating state, so the brake pad 11 rotates with the motor shaft 14, so that the brake pad 11 and the lever 12 may contact each other to detect whether the brake is abnormal. And, when an abnormality is detected, the motor is kept excited to prevent the brake from failing to brake effectively and causing dangers such as the robot's arm being smashed. Before the robot is powered on and starts to perform work and / or before the robot is powered off after completing the work, the brake 10 is detected in the motor excitation state to see if there is an abnormality, and when the brake 10 is abnormal, the motor excitation state is maintained, and an abnormal instruction is output, so that the brake of the robot 100 has good reliability and safety, and is easy to implement.

[0033] In one embodiment of the present invention, the control module is used to maintain the motor excitation state and output an abnormal instruction according to the detection of an abnormality in the brake 10. Further, the abnormal instruction includes: at least one of a warning instruction, a robot working speed reduction instruction, a user reminder processing instruction, and a user reminder to select a working mode instruction. Further, the warning instruction, for example, can attract people's attention through visual, acoustic, etc.; the robot working speed reduction instruction, that is, controlling the robot to continue to work after reducing the speed; the user reminder to select a working mode instruction, for example, reminds the user that the current option is to force power off, or power off after slowing down, that is, to ensure that the operation of the robot is under the control of the user, avoiding safety risks caused by abnormal brakes. In another embodiment of the present invention, the control module is used to control the brake not to release the brake when detecting an abnormality in the brake. Further, the detection module detects whether the brake is abnormal before the robot is powered on and starts to work. The control module detects that the brake is abnormal, controls the brake not to release the brake, maintains the motor excitation state, and outputs an abnormal instruction.

[0034] In one embodiment of the present invention, the detection module is used to detect whether the brake 10 is abnormal, and the detection of whether the brake 10 is abnormal includes: detecting whether the lever contacts the brake pad; the control module is used to maintain the motor excitation state and output an abnormal instruction according to the detection of the abnormality of the brake. The detection of the abnormality of the brake includes: not detecting the lever 12 contacting the brake pad 11. Specifically, the detection module detects whether the brake 10 is abnormal, that is, the detection module detects whether the brake 10 is in a reliable braking state. For a lever-type brake, the lever 12 needs to contact the brake pad 11 during the braking process to achieve braking. Further, there is friction between the brake pad 11 and the brake pad 15 to further achieve the braking of the brake. If the lever 12 is not detected to contact the brake pad 11, there may be an abnormal factor that the lever 12 fails to be successfully in the extended state. At this time, it is determined that the brake is abnormal, and an abnormal instruction is output while maintaining the motor excitation. Further, the detection of whether the lever 12 contacts the brake pad 11 includes: detecting whether the lever 12 contacts the brake pad 11 within a predetermined time. The detection of the abnormality of the brake includes: the blocking rod 12 is not detected to contact the brake pad 11 within a predetermined time. Exemplarily, the predetermined time is the time for the motor to rotate the brake pad 11 by one tooth angle. Or for example, the detection of the abnormality of the brake includes: the blocking rod 12 is not detected to contact the brake pad within a predetermined distance. Exemplarily, the predetermined distance is the distance between adjacent teeth of the motor brake pad 11.

[0035] In another embodiment of the present invention, the detection of whether the brake is abnormal includes: detecting the amount of movement of the motor within a predetermined time, and determining whether the amount of movement exceeds a preset value; the detection of the brake being abnormal includes: detecting that the amount of movement exceeds a preset value. Further, the amount of movement of the motor in the state of successful braking can be known in advance, that is, a preset value is set, and the preset value represents the amount of movement of the robot in the state of successful braking. By detecting the amount of movement of the motor within a predetermined time, if the amount of movement is greater than the preset value, it indicates that the brake is abnormal, otherwise, it indicates that the brake is working normally. Further, the brake being abnormal includes that the brake fails to brake normally or the braking performance of the brake is poor. If any of the above situations occurs, it is determined that the brake is abnormal because it does not have safe and reliable braking performance. Further, the predetermined time can be used to measure the amount of movement basis of the robot's entire braking process, or the predetermined time is used to measure the amount of movement basis of the robot's braking process excluding the idle stroke. In one embodiment, the starting point of the predetermined time is when the lever 12 contacts the brake pad 11, that is, the predetermined time is used to measure the amount of movement basis of the robot's braking process excluding the idle stroke. There may be two situations in which the multi-joint robot 100 cannot provide stable braking performance during the braking process. One is that the lever 12 is not effectively in the extended state, that is, it fails to contact the brake pad 11. The other is that the lever 12 is already in the effective state, but the friction between the brake pad 11 and the brake pad 15 is insufficient, so that the braking performance of the robot cannot be guaranteed. In the latter case, during the idle process, the robot has a large amount of movement, which makes the relative error of the determined movement large, and the movement distance between the brake pad 11 and the brake pad 15 when stopped by friction is relatively small. By setting the starting point of the predetermined time as the lever 12 contacts the brake pad 11, the accuracy of detecting brake abnormalities can be improved.

[0036] In one embodiment of the present invention, exemplarily, by detecting the amount of motion of the motor within a predetermined time, it is determined whether the brake is abnormal or not by judging whether it exceeds a preset value. The amount of motion of the motor can be determined by a position sensor. In this embodiment, the detection module includes at least two position sensors, and the at least two position sensors are respectively used to detect the amount of motion of the motor within a predetermined time. Only when the detection results are consistent, it is determined whether the amount of motion exceeds the preset value. By setting two position sensors, if the detection result of any one of the sensors is inaccurate, the detection results of the two sensors are inconsistent, and the detection results of the two sensors cannot be trusted, so as to prevent the process reliability of detecting whether the brake is abnormal or not due to the inaccuracy of position detection from being low. By setting at least two position detection sensors, the reliability of detecting the abnormality of the brake is improved, thereby improving the safety of the multi-joint robot 100. Further, when the detection results of the at least two position sensors are inconsistent, the detection results are not adopted, and the user is reminded that the robot has unsafe factors and is reminded to deal with them. Further, the at least two position sensors include at least one of a joint encoder, a speed / acceleration sensor, and a Hall sensor. Wherein, in one embodiment, the joint encoder is arranged at the output side of the motor. In summary, the multi-joint robot 100 of this embodiment uses dual position sensors to detect the movement of the motor, so that the reliability of the detection result is higher, and the reliability of the multi-joint robot is high.

[0037] The multi-joint robot 100 protected by the present invention detects whether there is an abnormality in the brake before the robot is powered on to start working and / or before the robot is powered off after finishing working, and when the motor is in an excitation state. In one embodiment, the control module is used to control the robot to power off or control the robot to release the brake to perform work according to detecting that the brake is normal. That is, when the brake is detected to be normal before the robot is powered on to start working, it indicates that the performance of the brake is guaranteed at this time, and the work is performed after the brake is released; when the brake is detected to be normal before the robot is powered off after finishing working, it indicates that the braking performance of the robot is normal at this time, and the robot will not smash its arm due to unsuccessful braking when the robot is powered off.

[0038] Ginseng Figure 4a and Figure 5a , respectively shows the time diagram of the industrial robot action start program and stop program, Figure 4bA time chart of the action start procedure of a multi-joint robot according to an embodiment of the present invention is shown. After the multi-joint robot 100 is powered on, the motor excitation is in the on state and the brake is in the braking state. The work instruction can be executed only after the brake is released. The time between the start of motor excitation and the release of brake is T1. The detection module detects whether there is an abnormality in the brake within T1. Specifically, the detection module detects whether the lever contacts the brake pad within T2. ​​The detection module detects whether the movement of the motor exceeds a preset value within T3. Only when the detection module meets the detection results in both the T2 time period and the T3 time period, it is determined that there is no abnormality in the brake, the brake is released, and the multi-joint robot executes the work instruction. Figure 5b The time chart of the stop program of a multi-joint robot of an embodiment of the present invention is shown. Conventionally, after the robot finishes executing the work, the motor excitation is in the on state, the brake is braked, and before the motor excitation is disconnected, that is, in the T4 time period, the detection module detects whether the brake is abnormal. Specifically, the detection module detects whether the lever contacts the brake pad within the T5 time period, and the detection module detects whether the motor movement exceeds the preset value within the T6 time period. Only when the detection results of the detection module in the T5 and T6 time periods meet the conditions, it is judged that there is no abnormality in the brake, the motor excitation is disconnected, and the robot performs the power-off operation. Specifically, within the above-mentioned T1 and T4 time periods, the motor excitation is in the on state, that is, the motor can rotate for the detection module to confirm whether the lever contacts the brake pad, and confirm the movement of the motor, and then judge whether the brake is abnormal. By detecting whether the brake is abnormal before the robot is powered on and performs the work, and detecting whether the brake is abnormal before the robot finishes the work and powers off, and by respectively detecting the lever contact state and the motor movement through the detection module to confirm whether the brake is abnormal, the brake works more reliably and the multi-joint robot has good safety.

[0039] The beneficial effects of the above preferred embodiments are: by detecting whether there is an abnormality with the brake in the motor excitation state before the robot is powered on to start working and / or before the robot finishes working and powers off, and maintaining the motor excitation state when the brake is abnormal, and outputting an abnormal instruction, the robot's brake has good reliability and safety and is easy to implement.

[0040] The present invention also protects a detection method of a multi-joint robot 100, which is applied to the multi-joint robot 100 described in any one of the above, and the method comprises:

[0041] Before the robot is powered on to start working and / or before the robot is powered off after finishing working, and when the motor is in the excitation state, check whether the brake is abnormal;

[0042] If an abnormality is detected in the brake, the motor excitation state is maintained and an abnormal command is output.

[0043] Furthermore, the method includes: when an abnormality of the brake is detected, controlling the brake not to release the brake.

[0044] The abnormal instruction includes at least one of a warning instruction, an instruction to reduce the working speed of the robot, an instruction to remind the user to process, and an instruction to remind the user to select a working mode.

[0045] Further, the detecting whether there is an abnormality in the brake includes: whether the lever contacts the brake pad; and the detecting whether there is an abnormality in the brake includes: not detecting that the lever contacts the brake pad.

[0046] Further, the detecting whether there is an abnormality in the brake includes: detecting the movement amount of the motor within a predetermined time, and determining whether the movement amount exceeds a preset value; the detecting whether there is an abnormality in the brake includes: detecting that the movement amount exceeds a preset value.

[0047] Further, the detecting whether there is an abnormality in the brake includes: detecting whether there is an abnormality in the brake by at least two position sensors respectively; the detecting whether there is an abnormality in the brake includes: when the results of the at least two position detectors are consistent, judging whether there is an abnormality in the brake.

[0048] Furthermore, the at least two position sensors include at least one of a joint encoder, a velocity / acceleration sensor, and a Hall sensor.

[0049] The detection method of the multi-joint robot protected by the present invention has specific implementation details that are the same as or similar to the implementation details of the multi-joint robot and will not be repeated here.

[0050] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A multi-joint robot, characterized in that: It includes a robotic arm and several joints, wherein the joints include: A housing; a motor; and a brake, wherein the brake comprises: A brake pad is sleeved on the motor shaft to rotate along with the motor shaft; A blocking rod, wherein the blocking rod comprises an extended state and a retracted state, and when the blocking rod is in the extended state, the blocking rod can contact the brake plate to at least partially restrict the rotation of the brake plate; The multi-joint robot comprises: A detection module is used to detect whether there is an abnormality in the brake before the robot is powered on and starts to perform work and / or before the robot is powered off after completing the work, and when the motor is in an excitation state; A control module, used for maintaining the motor excitation state and outputting an abnormal instruction according to detecting an abnormality of the brake; The control module is used to detect that there is an abnormality in the brake and control the brake not to release the brake; The abnormal instruction includes: at least one of: a warning instruction, an instruction to reduce the working speed of the robot, an instruction to remind the user to process, and an instruction to remind the user to select a working mode; The detecting whether there is an abnormality in the brake comprises: detecting whether the lever contacts the brake pad; the detecting whether there is an abnormality in the brake comprises: not detecting that the lever contacts the brake pad; The detecting whether there is an abnormality in the brake comprises: detecting the movement amount of the motor within a predetermined time, and determining whether the movement amount exceeds a preset value; the detecting whether there is an abnormality in the brake comprises: detecting that the movement amount exceeds a preset value; The starting point of the predetermined time is when the barrier rod contacts the brake pad; The detection module includes at least two position sensors, and the at least two position sensors are respectively used to detect the movement amount of the motor within a predetermined time, and only when the detection results are consistent, it is determined whether the movement amount exceeds a preset value.

2. The multi-joint robot according to claim 1, characterized in that: The at least two position sensors include at least one of a joint encoder, a speed and / or acceleration sensor, and a Hall sensor.

3. The multi-joint robot according to claim 1, characterized in that: The control module is used to control the robot to power off or control the robot to release the brake to perform work according to detecting that the brake is normal.

4. A detection method for a multi-joint robot, applied to the multi-joint robot according to any one of claims 1 to 3, characterized in that: The method comprises: Before the robot is powered on to start working and / or before the robot is powered off after finishing working, and when the motor is in the excitation state, check whether the brake is abnormal; If an abnormality is detected in the brake, the motor excitation state is maintained and an abnormal command is output.

Images