Safety system, joint assembly including the safety system, and robot including the joint assembly

Abstract

The present disclosure provides a safety system for use with a joint assembly including a motor and a brake coupled to the motor, the safety system including at least one set of sensors configured to detect at least one parameter associated with a safety function of the joint assembly, a drive circuit disposed within the joint assembly and coupled to the motor and the brake, and first and second processors disposed within the joint assembly, the first and second processors configured to receive signals indicative of the at least one parameter from the at least one set of sensors and to send a stop command directly to the drive circuit to stop the motor in response to a joint fault identified based on the signals received from the at least one set of sensors.

Description

[Technical Field]

[0001] The present disclosure relates to the technical field of robots, and more particularly to a safety system, a joint assembly including the safety system, and a robot including the joint assembly. [Background technology]

[0002] Functional safety is the part of a system or device that is concerned with the overall safety of that system or device, and relies on automatic protection (fail-safe) to respond to system or device inputs in a predictable manner and to operate correctly in the event of a fault. Automatic protection systems must be designed to respond appropriately to possible human error, hardware failures, and operational and / or environmental anomalies. The objective of functional safety is to protect people from direct or indirect unacceptable personal injury or health hazards by properly performing one or more automatic protection or safety functions. A safety system typically consists of one or more safety functions.

[0003] Safety functions are particularly important for robots. In conventional robots, all safety function inspection and monitoring must be performed by the main safety controller located in the control box. The main safety controller must collect sensor data from all robot joints and perform all relevant calculations to determine whether there is a functional failure. Summary of the Invention [Means for solving the problem]

[0004] One aspect of the present disclosure provides a safety system for use with a joint assembly including a motor and a brake coupled to the motor. The safety system includes at least one set of sensors configured to detect at least one parameter related to a safety function of the joint assembly, a drive circuit disposed within the joint assembly and coupled to the motor and the brake, and first and second processors installed within the joint assembly. The first and second processors are configured to receive signals indicative of the at least one parameter from the at least one set of sensors and to send a stop command directly to the drive circuit to stop the motor in response to a joint fault identified based on the signals received from the at least one set of sensors.

[0005] Another aspect of the present disclosure provides a joint assembly including a safety system, the joint assembly including a motor and a brake coupled to the motor. The safety system includes at least one set of sensors configured to detect at least one parameter related to a safety function of the joint assembly, a drive circuit disposed within the joint assembly and coupled to the motor and the brake, and first and second processors installed within the joint assembly. The first and second processors are configured to receive signals indicative of the at least one parameter from the at least one set of sensors and to send a stop command directly to the drive circuit to stop the motor in response to a joint fault identified based on the signals received from the at least one set of sensors.

[0006] Yet another aspect of the present disclosure provides a robot including a joint assembly including a motor, a brake coupled to the motor, and a safety system including at least one set of sensors configured to detect at least one parameter related to a safety function of the joint assembly, a drive circuit disposed within the joint assembly and coupled to the motor and the brake, and first and second processors installed within the joint assembly, the first and second processors configured to receive signals indicative of the at least one parameter from the at least one set of sensors and to send a stop command directly to the drive circuit to stop the motor in response to a joint fault identified based on the signals received from the at least one set of sensors.

[0007] The details of one or more embodiments of the present application are set forth in the drawings and description below. Other features, objects, and advantages of the present application will be apparent from the description, drawings, and claims. [Brief explanation of the drawings]

[0008] All features of the present disclosure will be more readily understood from the following detailed description, taken in conjunction with the accompanying drawings which illustrate various embodiments of the present disclosure. [Figure 1] FIG. 1 is a schematic diagram of a joint assembly according to an embodiment of the present disclosure. [Figure 2] FIG. 1 is a schematic diagram illustrating a configuration of a joint assembly according to an embodiment of the present disclosure. [Figure 3] FIG. 10 is a schematic diagram illustrating a configuration of a joint assembly according to another embodiment of the present disclosure. [Figure 4] FIG. 10 is a schematic diagram illustrating a configuration of a joint assembly according to another embodiment of the present disclosure. [Figure 5] FIG. 10 is a block diagram illustrating communication between a main controller and an articulation assembly according to an embodiment of the present disclosure. [Figure 6] FIG. 1 is a schematic diagram illustrating a configuration of a robot according to an embodiment of the present disclosure.

[0009] It should be noted that the drawings of the present disclosure are not drawn to scale. The accompanying drawings illustrate only typical aspects of the present disclosure and are not to be considered as limiting the scope of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0010] In order to clarify the above-mentioned objects, features, and advantages of the present disclosure, specific embodiments of the present invention will be described in detail below with reference to the drawings. In the following description, specific contents are described to fully understand the present invention, but the present invention can be implemented in embodiments different from the contents described in this specification, and those skilled in the art can make improvements without departing from the spirit of the present invention. Therefore, the present invention is not limited to the following specific embodiments.

[0011] According to one aspect of the present disclosure, a safety system for a joint assembly is provided. In the embodiment shown in FIG. 1 , the joint assembly 10 includes a motor 20 and a brake 30 coupled to the motor 20 to stop the motor. Preferably, the joint assembly 10 further includes a transmission 40, such as a reducer, that can change the speed output and torque output of the motor 20. The brake 30 may be directly coupled to the motor 20 or indirectly coupled to the motor 20 via the transmission 40 coupled to the motor 20. The brake 30 applies a braking force to the motor 20 or the transmission 40 based on a command from a processor or control device, thereby slowing or stopping the joint assembly 10 and stopping an element coupled to and driven by the joint assembly 10, such as a robot arm.

[0012] 1 , the safety system 50 detects a joint fault of the joint assembly 10 and locks the joint assembly 10 based on the detected joint fault. The safety system 50 includes at least one set of sensors 60 configured to detect at least one parameter related to a safety function of the joint assembly 10, a drive circuit 70 coupled to the motor 20 and the brake 30 and disposed in the joint assembly 10, and a first processor 80 and a second processor 81 disposed in the joint assembly 10. Specifically, the first processor 80 and the second processor 81 can be fixed on a common circuit board or different circuit boards within the joint assembly 10 and configured to receive signals indicative of the at least one parameter from the at least one set of sensors 60 and directly transmit a stop command to the drive circuit 70 to stop the motor 20 in response to a joint fault identified based on the signals received from the at least one set of sensors 60. The joint fault may include, for example, a mechanical or functional failure of a component of the joint assembly 10, or a failure of a physical connection or digital communication between components.

[0013] In the illustrated example, the first processor 80 and the second processor 81 may be microcontroller units (MCUs).

[0014] 2, in one embodiment, the at least one set of sensors 60 includes an input side position sensor 60a that measures the position of the rotor of the motor 20, and an output side position sensor 60b that measures the position of the output shaft of the transmission 40 that is coupled to the motor 20. At least one of the first processor 80 and the second processor 81 is configured to determine the presence or absence of a joint fault based on the measured position of the rotor of the motor 20 and the measured position of the output shaft of the transmission 40. The position sensors 60a, 60b may include, for example, a Hall effect position encoder.

[0015] For example, the first processor 80 receives signals from the position sensors 60a and 60b to obtain the measured rotor position of the motor 20 and the measured position of the output shaft of the transmission 40, respectively, and determines whether or not a joint fault exists based on the measured rotor position of the motor 20 and the measured position of the output shaft of the transmission 40. In a specific embodiment, the first processor 80 compares the measured rotor position of the motor 20 with a predetermined rotor position of the motor 20 to determine whether or not a joint fault exists. For example, if the deviation between the predetermined value and the measured value exceeds a predetermined threshold, it may be determined that a joint fault exists. Similarly, the first processor 80 may compare the measured position of the output shaft of the transmission 40 with a predetermined position of the output shaft of the transmission 40 to determine whether or not a joint fault exists. For example, if the deviation between the two exceeds a predetermined threshold, it may be determined that a joint fault exists. In another embodiment, the measured position of the rotor of the motor 20 and the measured position of the output shaft of the transmission 40 may be compared with corresponding predetermined values, and if the deviation amount of either of them exceeds a corresponding predetermined threshold, it may be determined that a joint fault has occurred. In another embodiment, the first processor 80 may compare the position of the rotor of the motor 20 with the position of the output shaft of the transmission 40 to determine whether a joint fault has occurred. For example, taking into account the gear ratio of the transmission 40, if the deviation amount between the measured position of the rotor of the motor 20 and the measured position of the output shaft of the transmission 40 exceeds a threshold, it may be determined that a joint fault has occurred.

[0016] It will be appreciated that the various calculations and / or comparisons described above may be performed by the second processor 81 or simultaneously by the first processor 80 and the second processor 81. Specifically, in one embodiment, the first processor 80 and the second processor 81 are both simultaneously coupled to and receive signals from the position sensors 60a and 60b. If necessary, the calculations described above may be performed by either the first processor 80 or the second processor 81. Alternatively, the first processor 80 and the second processor 81 may each perform a portion of the calculations. For example, the first processor 80 may determine whether a joint fault has occurred based on the signal from the position sensor 60a, and the second processor 81 may determine whether a joint fault has occurred based on the signal from the position sensor 60b. Alternatively, both the first processor 80 and the second processor 81 may perform all of the calculations, and a safety measure may be activated if either processor determines that a joint fault has occurred.

[0017] In another embodiment, at least one of the first processor 80 and the second processor 81 is configured to calculate the rotor rotation speed based on the measured rotor position, and calculate the output shaft rotation speed based on the measured position of the output shaft of the transmission 40, and determine the presence or absence of a joint failure based on the deviation between the rotor rotation speed and the output shaft rotation speed.

[0018] For example, the first processor 80 receives signals from the sensors 60a and 60b to obtain the measured rotor position of the motor 20 and the measured position of the output shaft of the transmission 40, respectively, calculates the rotor speed of the motor 20 based on the measured rotor position of the motor 20, and calculates the rotation speed of the output shaft of the transmission 40 based on the measured position of the output shaft of the transmission 40. Specifically, the first processor 80 samples the rotor position of the motor 20 twice at a fixed time interval to provide two position values ​​used to calculate the rotor speed of the motor 20. Similarly, the rotation speed of the output shaft of the transmission 40 can be calculated by sampling the position of the output shaft of the transmission 40 twice at a fixed time interval. In one embodiment, the first processor 80 may take into account the gear ratio of the transmission 40 and determine that a joint fault has occurred if the deviation amount exceeds a threshold value when comparing the calculated rotor speed of the motor 20 with the calculated speed of the output shaft of the transmission 40. In another embodiment, the first processor 80 can compare the calculated rotor speed of the motor 20 with a predetermined rotor speed of the motor 20 to determine whether or not a joint failure has occurred. For example, if the deviation between the two exceeds a threshold, it may be determined that a joint failure has occurred. Similarly, the first processor 80 can compare the calculated rotation speed of the output shaft of the transmission 40 with a predetermined rotation speed of the output shaft of the transmission 40 to determine whether or not a joint failure has occurred. For example, if the deviation between the two exceeds a threshold, it may be determined that a joint failure has occurred.

[0019] Similarly, it will be understood that the various calculations and / or comparisons described above may be performed by the second processor 81, or may be performed jointly or separately by the first processor 80 and the second processor 81.

[0020] According to an embodiment of the present disclosure, the sensor data is collected locally by the first processor 80 and / or the second processor 81, so that the sampling frequency is high and the time interval between two samples is short, resulting in more accurate calculated rotor speed of the motor 20 and calculated rotation speed of the output shaft of the transmission 40.

[0021] 3, in one embodiment, the at least one set of sensors includes a current sensor 60c that detects a current of the motor 20 and a torque sensor 60d that detects an output torque of the transmission 40 coupled to the motor 20. At least one of the first processor 80 and the second processor 81 is configured to determine the presence or absence of a joint fault based on the measured current and the measured torque.

[0022] For example, the first processor 80 obtains the measured current of the motor 20 from the signal of the current sensor 60c, obtains the measured torque of the transmission 40 from the signal of the torque sensor 60d, and calculates the estimated torque based on the measured current of the motor 20. Taking into account the gear ratio of the transmission 40, the first processor 80 compares the calculated estimated torque of the motor 20 with the measured torque of the transmission 40, and if the deviation between the two exceeds a threshold, determines that a joint failure has occurred.

[0023] The first processor 80 may compare at least one of the calculated estimated torque of the motor 20 and the measured torque of the transmission 40 with a corresponding preset torque to determine whether or not a joint failure has occurred.

[0024] It will also be appreciated that the various calculations and / or comparisons described above may be performed by the second processor 81, or by the first processor 80 and the second processor 81, respectively. Specifically, in one embodiment, the first processor 80 and the second processor 81 are both simultaneously coupled to and receive signals from the current sensor 60c and the torque sensor 60d. If desired, the calculations described above may be performed by either the first processor 80 or the second processor 81. Alternatively, both the first processor 80 and the second processor 81 may be utilized, with each performing all calculations and activating a safety measure if either processor determines that a joint fault has occurred.

[0025] In one embodiment, one of the first processor 80 and the second processor 81 calculates an estimated torque of the motor 20 based on the current of the motor 20, and the other of the first processor 80 and the second processor 81 acquires a measured torque of the transmission 40 based on a signal from the torque sensor 60d. As described above, the first processor 80 and the second processor 81 may compare the calculated estimated torque and measured torque with corresponding thresholds, or compare the calculated estimated torque of the motor 20 with the measured torque of the transmission 40, to determine whether or not a joint fault has occurred.

[0026] 4, in one embodiment, the at least one set of sensors 60 includes an input-side position sensor 60a that measures the position of the rotor of the motor 20, an output-side position sensor 60b that measures the position of the output shaft of the transmission 40, a current sensor 60c that detects the current of the motor 20, and a torque sensor 60d that detects the output torque of the transmission 40. One of the first processor 80 and the second processor 81 is arranged to determine the presence or absence of a joint fault based on the measured position of the rotor of the motor 20 and the measured position of the output shaft of the transmission 40, for example, by the method described above, and the other of the first processor 80 and the second processor 81 is configured to determine the presence or absence of a joint fault based on the measured current of the rotor of the motor 20 and the measured torque of the output shaft of the transmission 40, for example, by the method described above.

[0027] In one embodiment, the first processor 80 and the second processor 81 communicate with each other, and when one of the processors detects a joint fault, it sends notification information to the other processor, thereby realizing cross-checking between the two processors 80, 81. Also, by having the first processor 80 and the second processor 81 communicate with each other, one processor can obtain sensor data from the other processor, which is more efficient than collecting all data directly from the sensors.

[0028] In one embodiment, the first processor 80 and the second processor 81 are configured with different technical specifications, which reduces the probability of the two processors failing at the same time and allows the two processors to validate each other to identify processor failures.

[0029] If it is determined that a joint fault exists, the first processor 80 and / or the second processor 81 send a stop signal to the drive circuit 70, and the drive circuit 70 responds to the stop signal by, for example, cutting off the current to the motor 20 or activating the brake 30 to stop the motor 20, thereby cutting off the torque output and locking the joint assembly 10.

[0030] In one embodiment, referring to FIG. 5 , the safety system further includes a main controller 90. The main controller 90 communicates with the first processor 80 and the second processor 81 and, upon receiving a joint failure notification from the first processor 80 and / or the second processor 81, generates a stop command for the entire apparatus utilizing the joint assembly 10. For example, the main controller 90 locks all other joint assemblies of the robot in response to the joint failure notification. The main controller 90 may further include one or more processors 91, such as MCUs, configured to receive signals from the sensors 60 in the joint assembly 10 and perform the various calculations and / or decisions described above independently of the calculations or decisions performed by the first processor 80 and the second processor 81 in the joint assembly 10. Thus, a determination regarding a joint failure can be further confirmed by related calculations in the main controller 90, thereby improving the reliability of the safety check. In one embodiment, the main controller 90 has direct control over the main power switch and will turn off the main power switch and lock out the entire device if the main controller 90 determines, based on data collected from sensors in the joint assemblies and / or elsewhere in the system, that there is a fault in the system.

[0031] According to another aspect of the present disclosure, the present disclosure further provides a joint assembly having the safety assembly described above in the various embodiments, and a robot having the joint assembly. Referring to FIG. 6 , in one embodiment, a robot 100 includes at least two arms 101 coupled to each other via joint assemblies 10, each of which is rotatable to adjust the position of an end effector 102 (e.g., a clamp) at the end of the connected arm. Another embodiment provides at least two joint assemblies 10. As described above, each joint assembly 10 includes a pair of processors and at least one set of sensors, and all of the joint assemblies 10 are coupled to and communicate with a common main controller. In this case, the processor of the main controller simultaneously receives signals from the sensors in at least one, and preferably all, of the joint assemblies 10, performs the various calculations and / or decisions described above, and provides additional checks for functional failures of each joint assembly 10.

[0032] According to some embodiments of the present disclosure, two processors disposed in the joint assembly perform safety functions related to at least joint position limits, joint velocity limits, or joint torque limits within the joint assembly, rather than all calculations and checks being completely performed by the main control device. The sensors and local processors use, for example, a high-speed communication protocol to achieve faster communication speeds than communication between the main control device and the sensors in the joint assembly, eliminating or reducing the risk of communication failure. Furthermore, if the joint assembly detects an abnormality in any safety function related to joint position, velocity, or torque, it immediately locks itself safely. Compared to conventional joint assemblies, fault detection and response delays are significantly faster.

[0033] According to some embodiments of the present disclosure, two processors are located within the joint assembly, and the computational load of safety checks is shared among the robot's joint assemblies, rather than being concentrated in a main controller having one or more processors. This sharing of the load allows for shorter check intervals and faster fault detection. It also adds additional safety protection to the joint assembly checks in addition to the main controller. Furthermore, according to some embodiments, because joint velocities are calculated locally at the joints, the time interval between two sampled joint position data for calculating joint velocities is much smaller than in conventional joint assemblies. Therefore, the joint velocities used in safety checks are more appropriate, thereby improving the accuracy and reliability of checks for all safety functions that depend on joint velocity data.

[0034] The terms used herein are for the purpose of describing particular embodiments and are not intended to limit the disclosure. As used herein, singular forms such as "a," "an," and "the" are intended to include the plural unless the context clearly dictates otherwise. Additionally, as used herein, the terms "comprise" or "include" refer to the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or combinations thereof. The terms "optional" or "any" mean that the subsequently stated event or circumstance may or may not occur, and the description includes both instances in which the event occurs and instances in which it does not occur.

[0035] As used in the present specification and claims, "approximate" terms are used to modify quantitative expressions that can vary within a range without causing a change in basic function. Thus, values ​​modified with terms such as "about," "approximately," and "substantially" are not limited to the specified value. In some circumstances, approximation terms correspond to the precision of the instrument used to measure the value. In the present specification and claims, range limitations are combinable and / or interchangeable, unless otherwise clearly indicated by the context. Such ranges include the specified range as well as all subranges.

[0036] It is intended that all apparatus and step-plus-function elements in the following claims, including their corresponding structure, material, or acts, and their equivalents, achieve that function in combination with any structure, material, or act specifically claimed in any other claim. The descriptions in this disclosure are provided for purposes of illustration and description and are not intended to be exhaustive or to limit the invention to the precise form disclosed. Those skilled in the art will recognize that various modifications and variations can be made without departing from the scope and spirit of the disclosure. These embodiments were chosen and described in order to best explain the principles and practical applications of the disclosure and to enable skilled artisans to appreciate various modified embodiments of the disclosure suitable for particular applications.

Claims

1. 1. A safety system for use with a joint assembly including a motor and a brake coupled to the motor, comprising: The safety system comprises: at least one set of sensors configured to detect at least one parameter related to a safety function of the joint assembly; a drive circuit disposed within the joint assembly and coupled to the motor and the brake; a first processor and a second processor installed within the joint assembly; the first processor and the second processor are configured to receive signals indicative of at least one of the parameters from the at least one set of sensors, and to send a stop command directly to a drive circuit to stop the motor in response to a joint fault identified based on the signals received from the at least one set of sensors.

2. the at least one set of sensors includes an input side position sensor that measures a position of a rotor of the motor, and an output side position sensor that measures a position of an output shaft of a transmission that is coupled to the motor; 2. The safety system of claim 1, wherein at least one of the first processor and the second processor is configured to determine the presence or absence of a joint fault based on the measured position of the rotor and the measured position of the output shaft of the transmission.

3. 3. The safety system according to claim 2, wherein at least one of the first processor and the second processor is configured to compare the measured position of the rotor with the measured position of the output shaft and determine whether or not a joint fault exists based on the amount of deviation between the two.

4. 3. The safety system of claim 2, wherein at least one of the first processor and the second processor is configured to compare at least one of the measured position of the rotor and the measured position of the output shaft with corresponding predetermined positions to determine whether or not a joint fault exists.

5. 3. The safety system according to claim 2, wherein at least one of the first processor and the second processor is configured to calculate a rotation speed of the rotor based on the measured position of the rotor, and to calculate a rotation speed of the output shaft based on the measured position of the output shaft, and to determine the presence or absence of a joint failure based on a deviation amount between the rotation speed of the rotor and the rotation speed of the output shaft.

6. 3. The safety system according to claim 2, wherein at least one of the first processor and the second processor is configured to calculate a rotation speed of the rotor based on the measured position of the rotor, and to calculate a rotation speed of the output shaft based on the measured position of the output shaft, and to compare at least one of the calculated rotation speed of the rotor and the calculated rotation speed of the output shaft with a corresponding predetermined speed to determine whether or not a joint fault exists.

7. 2. The safety system of claim 1, wherein the at least one set of sensors includes a current sensor configured to detect a current of the motor and a torque sensor configured to detect an output torque of a transmission coupled to the motor, and at least one of the first processor and the second processor is configured to determine whether or not a joint fault exists based on the measured current of the motor and the measured torque of the transmission.

8. 8. The safety system according to claim 7, wherein at least one of the first processor and the second processor is configured to calculate an estimated torque of the motor based on the measured current, compare the calculated estimated torque of the motor with the measured torque of the transmission, and determine whether or not a joint failure exists based on the amount of deviation between the two.

9. 8. The safety system of claim 7, wherein at least one of the first processor and the second processor is configured to calculate an estimated torque of the motor based on the measured current, and compare at least one of the calculated estimated torque of the motor and the measured torque of the transmission with a corresponding predetermined torque to determine whether or not a joint fault exists.

10. 8. The safety system of claim 7, wherein the first processor is arranged to calculate an estimated torque of the motor based on the measured current and determine the presence or absence of a joint fault based on the calculated estimated torque, and the second processor is configured to determine the presence or absence of a joint fault based on the measured torque of the transmission.

11. 8. The safety system of claim 7, wherein the first processor is arranged to calculate an estimated torque of the motor based on the measured current, and the second processor is configured to obtain a measured torque of the transmission from the torque sensor and compare the calculated estimated torque with the measured torque to determine whether a joint fault exists.

12. The at least one set of sensors includes: an input position sensor arranged to measure the position of the rotor of the motor; an output position sensor arranged to measure the position of an output shaft of a transmission coupled to the motor; a current sensor arranged to measure a current in the motor; a torque sensor arranged to measure a torque output by the transmission; 2. The safety system of claim 1, wherein one of the first processor and the second processor is arranged to determine the presence or absence of a joint fault based on the measured position of the rotor of the motor and the measured position of the output shaft of the transmission, and the other of the first processor and the second processor is configured to determine the presence or absence of a joint fault based on the measured current of the motor and the measured torque of the transmission.

13. 2. The safety system of claim 1, wherein the first processor and the second processor are configured to communicate with each other and send notifications to each other when a joint failure is determined to exist.

14. 10. The safety system of claim 1, wherein the first processor and the second processor are configured with different technical specifications.

15. 2. The safety system of claim 1, wherein the first processor and the second processor are configured to lock the joint assembly by interrupting torque output or engaging a brake of the joint assembly.

16. 2. The safety system of claim 1, further comprising a main control device that communicates with the first processor and the second processor and is configured to generate a stop command for an entire apparatus that utilizes the joint assembly when the main control device receives a joint fault notification from either the first processor or the second processor.

17. 1. A joint assembly comprising: An articulated assembly comprising a motor, a brake coupled to the motor, and a safety system according to any one of claims 1 to 16.

18. A robot, A robot comprising at least one joint assembly according to claim 17.

19. 20. The robot of claim 18, wherein the at least one joint assembly includes at least two joint assemblies each in communication with a common main controller.

20. 20. The robot of claim 19, wherein the main controller includes one or more processors configured to receive signals from at least one set of sensors in at least one of the joint assemblies, determine whether a joint fault exists based on the received signals, and lock the robot in response to the joint fault.

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