Collision detection methods and corresponding controllers, mechanical joints, and robotic arms

Abstract

This invention belongs to the field of robotics technology, specifically disclosing a method for detecting collisions and a corresponding controller, mechanical joint, and robotic arm. The method is used to detect whether an automated device collides while moving along a planned path. The automated device includes mechanical joints and a position information acquisition device. The position information acquisition device is used to collect the position information of the mechanical joints. The method includes the following steps: monitoring the real-time position information output by the position information acquisition device; calculating the error between the real-time position information and the corresponding planned position information in the planned path; if the error exceeds a preset threshold, a collision is determined to have occurred; otherwise, a collision is not considered to have occurred, and the real-time position information continues to be monitored, and the error and the threshold continue to be compared. The advantage of this invention is that it simplifies the calculation process and improves the robot's reaction speed.

Description

Technical Field

[0001] This invention relates to the field of robotics engineering technology, and in particular to a method for detecting collisions and a corresponding controller, mechanical joint, and robotic arm. Background Technology

[0002] Since industrial robots were put into practical use, the environments in which they can be applied have become increasingly diverse. Compared to traditional robots used in large-scale production, the newly developed collaborative robots are more flexible and capable of self-control. In other words, collaborative robots are more "intelligent."

[0003] Currently, collaborative robots are generally defined as robots that can directly interact with humans (human operators) within a defined collaborative area. A problem that arises is that, to ensure the safety of the human operator, collaborative robots must possess collision detection and automatic stopping capabilities.

[0004] The industry typically uses a current loop method—detecting sudden changes in motor current—to determine if a collision has occurred. This current loop method is achieved by controlling the current of the drive motors in each mechanical joint, requiring the establishment of a dynamic model. This involves converting the position and velocity information from the encoders in the mechanical joints into torque information; it also requires converting the current information of the drive motors in the mechanical joints into torque information. Multiple conversions lead to a decrease in accuracy, and most dynamic models utilize information from both speed and position encoders. Since mechanical joints are not absolutely rigid, the information from the two encoders is not completely synchronized, which introduces further errors.

[0005] To compensate for the aforementioned errors, torque sensors (including joint torque sensors, base torque sensors, end effector torque sensors, etc.) are sometimes added in addition to the methods described above to improve detection accuracy. However, this approach is too expensive, and adding torque sensors to the confined space of the robot's mechanical joints makes the structural design extremely complex, while also increasing the size and weight of the mechanical joints.

[0006] Therefore, there is an urgent need to develop a better collision detection method for collaborative robots. Summary of the Invention

[0007] To address the aforementioned shortcomings, this invention first provides a collision detection method. This method is used to detect whether a collision occurs when an automated device moves along a planned path. The automated device includes mechanical joints and a position information acquisition device, which is used to acquire the position information of the mechanical joints.

[0008] The method includes the following steps:

[0009] The method includes the following steps:

[0010] Monitor the real-time location information output by the location information acquisition device;

[0011] Calculate the error between the real-time location information and the corresponding planned location information in the planned path;

[0012] If the error exceeds a preset threshold, a collision is determined to have occurred; otherwise, a collision is not considered to have occurred, and the real-time location information continues to be monitored, and the error and the threshold continue to be compared.

[0013] In the above method, after a collision is determined to have occurred, the automated equipment stops moving and issues an alarm.

[0014] In the above method, the threshold is linearly related to the rotational speed of the motor driving the mechanical joint, that is:

[0015] U 单 =a 单 θ′+b 单

[0016] Among them, U 单 a represents the threshold of the mechanical joint. 单 and b 单 θ' is an empirical coefficient associated with the mechanical joint, and θ' is the rotational speed of the motor driving the mechanical joint.

[0017] In the above method, considering each mechanical joint individually, the error and the threshold U are compared for each mechanical joint. 单 , among which, U 单 This represents the threshold value when considering each of the mechanical joints individually, if the error of any one of the mechanical joints exceeds the threshold value U. 单 If the collision occurs, it is determined that a collision has taken place.

[0018] In the above method, a set of mechanical joints with parallel drive shafts are considered as associated joints. Taking these associated joints into account, the threshold U... 关 It is linearly related to the rotational speed of the motor driving the associated joint. For example, the threshold U 关 It could be a comprehensive value derived from experience; or, a threshold U. 关 It could also be an independent threshold U for each of the mechanical joints in the associated joints, taking into account the associated joints. 关 The cumulative value, where i represents the sequence number of the i-th mechanical joint in the associated joint, i.e.:

[0019] U关 =∑U 关i =∑a 关i θ′ i +∑b 关i

[0020] Among them, U 关 U represents the threshold value of the associated joint. 关i a represents the independent threshold of the i-th mechanical joint in the associated joints. 关i and b 关i It is an empirical coefficient related to the i-th mechanical joint, θ′ i The rotational speed of the i-th motor driving the i-th mechanical joint;

[0021] If the sum of the errors of all the mechanical joints in the associated joint exceeds the threshold U 关 If the collision occurs, it is determined that a collision has taken place.

[0022] In the above method, considering all the mechanical joints as a whole, the threshold U all It is linearly related to the rotational speed of the motors driving all the aforementioned mechanical joints. For example, the threshold U all It could be a comprehensive value derived from experience; or, a threshold U. all It could also be an independent threshold U for each of the mechanical joints when considering all the mechanical joints as a whole. alli The cumulative value, where i represents the sequence number of the i-th mechanical joint, i.e.:

[0023] U all =∑U alli =∑a alli θ′ i +∑b alli

[0024] Among them, U all U represents the threshold value for all the aforementioned mechanical joints. alli a represents the threshold value of the i-th mechanical joint. alli and b alli It is an empirical coefficient related to the i-th mechanical joint, θ′ i The rotational speed of the i-th motor driving the i-th mechanical joint;

[0025] If the sum of the errors of all the aforementioned mechanical joints exceeds the threshold U all If the collision occurs, it is determined that a collision has taken place.

[0026] In the above method, the threshold further includes a heavy threshold and a light threshold, wherein the heavy threshold is greater than the light threshold. When the error or the sum of the errors exceeds the heavy threshold, the corresponding mechanical joint returns along the original path. When the error exceeds the light threshold but does not exceed the heavy threshold, the corresponding mechanical joint stops.

[0027] In the above method, the error and the threshold are compared N times consecutively. If the error exceeds the threshold in P comparisons, a collision is determined to have occurred; otherwise, a collision is not considered to have occurred. Here, N is a natural number and P ≤ N.

[0028] In the above method, the P times can be consecutive or non-consecutive.

[0029] In the above method, during N consecutive comparisons, when the error exceeds the threshold for P' comparison results, the torque output by the drive component is reduced to slow down the movement speed of the mechanical joint, where P' < P.

[0030] Compared to existing technologies, the above method only collects one type of information, namely location information. It determines whether a collision has occurred by comparing the actual location information with the predetermined location information. This not only reduces the amount of information that needs to be collected, but also simplifies the calculation process by including only addition, subtraction and logical judgment calculations. The resulting judgment is still highly reliable.

[0031] To further improve the reliability of the judgment and filter out noise information, this method adopts a continuous comparison approach to implement the judgment process. A collision is determined to have occurred only if the results of P (P≤N) of the N consecutive comparisons exceed the threshold, thereby avoiding false alarms.

[0032] The present invention also proposes a controller for detecting collisions, which is used to detect whether a collision occurs when an automated device moves in a planned path, wherein the automated device includes mechanical joints, and the controller includes;

[0033] A signal acquisition unit is used to acquire the real-time position information of the mechanical joint.

[0034] An error calculation unit is used to calculate the error between the real-time location information and the corresponding planned location information in the planned path;

[0035] The cumulative determination unit is used to determine whether a collision has occurred based on the method described above.

[0036] The controller described above also includes an alarm unit, which is used to sound an alarm and / or lock the mechanical joint by means of sound / light / electricity after the cumulative determination unit determines that a collision has occurred, and to provide a prompt by means of sound / light / electricity after the danger has passed.

[0037] Compared to existing technologies, the aforementioned method and controller not only consider a single isolated mechanical joint but also comprehensively assess the collision conditions of several interconnected mechanical joints. Here, the interconnected mechanical joints refer to a group of mechanical joints with parallel drive shafts. By employing a comprehensive assessment approach, the intensity of the collision can be evaluated from multiple angles. By setting more targeted thresholds, the force conditions of individual joints and interconnected joints are assessed separately. Then, the weights of the two force conditions can be determined based on the actual application environment, and the decision logic is comprehensively determined.

[0038] Furthermore, the system can comprehensively consider the stress conditions of individual joints, interconnected joints, and the entire system as a whole. First, the stress conditions of individual joints, interconnected joints, and the entire system as a whole are assessed separately. Then, the weights of these three stress conditions are determined based on the actual application environment, and the overall decision logic is determined accordingly. By including all mechanical joints of the entire automated equipment in the consideration, collisions are considered at three levels (single joint, interconnected joints, and the entire machine). Depending on the weights, collision decisions can be flexibly adjusted for different environments and requirements.

[0039] The present invention also proposes a computer-readable storage medium storing instructions that, when executed, enable the computer to implement the collision detection method as described above.

[0040] Accordingly, the present invention proposes a mechanical joint that implements the above-described collision detection method.

[0041] Compared to existing technologies, the aforementioned mechanical joint has a simple and rapid collision determination process, and can flexibly adjust the threshold and weights according to different environments and needs, greatly increasing the adaptability of the mechanical joint to the environment.

[0042] Accordingly, the present invention also proposes a robotic arm that implements the above-described collision detection method.

[0043] Compared to existing technologies, the above-mentioned robotic arm has a simple and rapid collision judgment process, and can flexibly adjust the threshold and weights according to different environments and needs, which greatly increases the adaptability of the robotic arm to the environment. Attached Figure Description

[0044] Figure 1 This is a structural block diagram of the mechanical joint in this invention;

[0045] Figure 2 This is a schematic diagram of the mechanical joint in this invention;

[0046] Figure 3 This is a flowchart of the collision detection method in this invention;

[0047] Figure 4 This is a schematic diagram of the interrelated mechanical joints in this invention;

[0048] Figure 5 This is a curve comparison chart of the actual angle information and the theoretical angle information output by the position encoder in this invention;

[0049] Figure 6 This is a block diagram of an exemplary controller in this invention. Detailed Implementation

[0050] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Although the description of the present invention is presented in conjunction with preferred embodiments, this does not mean that the features of the invention are limited to these embodiments. On the contrary, the purpose of describing the invention in conjunction with embodiments is to cover other options or modifications that may be derived based on the claims of the present invention. To provide a deep understanding of the invention, many specific details will be included in the following description. The invention may also be implemented without using these details. Furthermore, to avoid confusion or obscuring the focus of the invention, some specific details will be omitted in the description. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of the present invention can be combined with each other.

[0051] It should be noted that in this specification, similar reference numerals and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures, and is assumed to be the same definition.

[0052] It should also be stated that the methods and processes in this invention are numbered for ease of reference, not to limit the order of steps. If there is a sequence between the steps, the textual description shall prevail.

[0053] The key concept of this invention lies in abandoning the existing approach of determining whether automated equipment has collided by detecting the output current of the drive motor. Instead, it utilizes the position information acquisition devices commonly found in existing automated equipment for monitoring. Specifically, the monitoring approach involves comparing the monitored real-time position information with pre-calculated planned position information. When the error exceeds a certain threshold, a collision is determined to have occurred. This solution does not require modifications to the existing structure of existing products; only an upgrade to the control software is needed. Compared to the often six-month or longer deployment cycle for automated equipment, software upgrades can significantly shorten the time to operational use.

[0054] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0055] Collaborative robots typically work as members of the production line, performing repetitive tasks requiring high precision. Since human operators will be present within the robot's operating range, collision detection is essential for safety. For collisions with humans, the accuracy of the collision detection must be high, and the detection speed (i.e., reaction speed) should be as fast as possible. Furthermore, collaborative robots often do not only participate in the production of a single product; when they change roles, their collision detection thresholds usually need to be adjusted. Therefore, the ability to adapt to frequent parameter adjustments is also expected.

[0056] Figure 1 This is a structural block diagram of the mechanical joint discussed in this invention, showing a block diagram of a relatively general embodiment of the mechanical joint. As shown in the figure, the mechanical joint includes: a motor 1, a reducer 2, a shaft-end encoder 3, a shaft 4, and an output end 5.

[0057] Motor 1 (driving component) is fixedly connected to shaft 4 (transmission component) to drive shaft 4 to rotate. Shaft 4 is fixedly connected to output end 5 (torque output end) so as to drive output end 5 to rotate.

[0058] The reducer 2 is used to reduce the speed of motor 1.

[0059] The shaft-end encoder 3 (information acquisition device) is typically positioned close to the output end 5 to acquire data as close as possible to the actual value. The shaft-end encoder 3 may include a speed encoder, a position encoder 31 (position information acquisition device), etc. The position encoder 31 is preferably positioned very close to the output end 5, ensuring that the acquired position information is as close as possible to the actual position offset. Alternatively, due to space constraints within the mechanical joint, the position encoder 31 may be rigidly connected and positioned slightly further from the output end 5, for example... Figure 1The position marked by the dashed box is the position of encoder 31. Figure 1 The position encoder 31, marked by the dashed box in the middle, is rigidly connected to the output end 5 via the shaft 4. Under this connection method, since the position encoder 31 is a certain distance away from the actual force-bearing position, the acquired position information will contain a fixed deviation. However, this deviation can be corrected by calculation equations. This invention will not discuss this point in detail.

[0060] exist Figure 1 Based on the structure shown, this invention only monitors the real-time position information output by the position encoder 31, compares it with the planned position information, and thus achieves the purpose of collision detection.

[0061] Figure 2 This is a schematic diagram of an actual mechanical joint in this invention. The encoder 31 shown in the figure is close to the output end 5, which is a position that is more conducive to collecting position information. In the subsequent calculation process, it is not necessary to add a step to correct for fixed errors.

[0062] Figure 3 by Figure 2 Based on the structure shown, a flowchart of an embodiment of the collision detection method of the present invention is illustrated. The decision process in the figure includes three decision logics: making a decision on an independent mechanical joint, making a decision on a group of related joints, and making a decision on all mechanical joints as a whole. In practical applications, one or two of these logics can be selected for implementation as needed, or as follows... Figure 3 As shown, three logics are applied simultaneously for actual execution, which will not be elaborated upon in this article. For example, if only the first logic is selected to perform the collision detection, then in practical applications, only the force situation of a single mechanical joint is considered in isolation. As long as the error of any one mechanical joint exceeds the threshold U... 单 If this happens, the collaborative robot's operation needs to be stopped / paused. For example, if both the first and second logic methods are selected to perform collision detection, then in practical applications, the force conditions of individual joints and related joints are considered comprehensively. When the error of a single joint exceeds the threshold U... 单 Or / and the error of a set of associated joints exceeds the threshold U. 关 The collaborative robot needs to stop working only when the drive shafts are parallel. Here, a linked joint refers to a group of mechanical joints with parallel drive shafts.

[0063] The collision detection method of the present invention can be used to detect whether a collision occurs when an automated device (e.g., a collaborative robot) moves along a planned path. The automated device is equipped with a position information acquisition device (e.g., an encoder 31) for collecting position change information of the automated device. The collection of position change information can also refer to the collection of position change information of critical / sensitive nodes of the automated device. For example, in this embodiment, the position changes of the mechanical joints of the collaborative robot are monitored.

[0064] Figure 4 The diagram shows a typical collaborative robot. The robot includes six mechanical joints 42, 43, 45, 47, 48, and 49, and connecting rods 44 and 46 linking these joints. Mechanical joints 42, 43, 45, 47, 48, and 49 can rotate along the axes shown by the dotted lines in the diagram. This rotational motion is captured by a position information acquisition device (e.g., an encoder 31) and transmitted to a controller 415, which then determines the robot's motion state. The collaborative robot is fixed to a fixed object such as the ground or a tabletop via a base 41. The controller 415, used to control the robot's motion, is connected to the robot via a cable. Before each of the mechanical joints begins to move, the controller 415 of the collaborative robot plans the movement path for each mechanical joint. During each data acquisition cycle, the controller 415 receives the real-time position information collected by the position encoder 31 in each mechanical joint. Corresponding to the time point when the position encoder 31 collects data, the controller 415 can obtain the planned position information according to the planned path. The error between each real-time position information and the planned position information is calculated, and the error is compared with a threshold. If the error exceeds the threshold range, the movement of the mechanical joint is considered to be outside the range of the planned path.

[0065] Back Figure 3 , Figure 3 The given embodiments include the following steps:

[0066] Step S1: Collect real-time position information for each mechanical joint. Different position information acquisition devices will collect different information. Figure 2 The mechanical joint shown is used to collect angle information. Furthermore, this step, or the process shown in this flowchart, is not a one-time event, but is repeatedly executed at a cycle T during the collaborative robot's operation until a collision alarm occurs, at which point the data acquisition and judgment process temporarily stops.

[0067] Step S2: Calculate the error between the real-time location information collected in step S1 and the planned location information.

[0068] In steps S3 and S4, the error is compared with the threshold U for each mechanical joint. 单 And record whether the error in this loop exceeds the threshold U. 单 When the error exceeds a threshold, a collision is considered to have occurred. Determining whether a collision has occurred through simple subtraction and comparison operations greatly simplifies the decision-making process and improves efficiency. According to the existing technology mentioned in the background section, a computational model needs to be established based on mechanical principles, kinematic principles, and parameters such as motor current. This is not only computationally complex but also consumes a significant amount of CPU time, meaning the reaction speed of the collaborative robot will decrease. However, the decision-making method described in this embodiment can improve the reaction speed of the collaborative robot.

[0069] Furthermore, the threshold U 单 This may include the re-threshold U 单U and light threshold U 单L There are two thresholds: a heavy threshold, which is a threshold given under more stringent conditions, generally indicating a serious impact when the error exceeds the heavy threshold. Similarly, a light threshold, which is a threshold given under more lenient conditions, generally indicating that although a problem has occurred, the impact is not severe when the error exceeds the light threshold (but not the heavy threshold). Therefore, in the subsequent processing of this embodiment, when the error is greater than the light threshold but less than the heavy threshold, the collaborative robot stops and alarms, waiting for manual intervention to eliminate the danger (steps S11 and S10). When the error exceeds the heavy threshold, the collaborative robot returns along the original path and alarms again. Finally, after receiving a safety notification, it continues to execute the next operation command (steps S9 and S10).

[0070] To improve the reliability of the judgment and filter out noisy samples, this embodiment only determines a collision after multiple errors exceed a threshold. If P records in N consecutive cyclic comparisons show errors exceeding the threshold, it is determined that the mechanical joint / related joints / all joints as a whole have collided, and an alarm should be considered. The P instances can be continuous or intermittent, depending on the specific usage environment. Typically, the setting of P is different in both cases.

[0071] As a compromise, during N consecutive cyclic comparisons, when the error exceeds the threshold for P' (P' < P) comparison results, the torque output by the drive component is reduced to slow down the movement speed of the mechanical joint, thereby reducing the damage / loss caused by possible collisions.

[0072] Steps S5 and S6, for a set of associated joints, for example Figure 4The mechanical joints 43, 45, and 47 shown can be used to accumulate the errors of all mechanical joints in this group of associated joints and whether they exceed the threshold U. 关 Those skilled in the art will understand that, based on the foregoing definition of associated joints, Figure 4 There may also be a group of associated joints consisting of mechanical joints 43, 45, 47, and 49, and another group of associated joints consisting of mechanical joints 42 and 48, as well as other associated joints that conform to the definition. In practical application of this invention, the choice of which associated joints to focus on can be determined by actual needs.

[0073] Continuing with steps S5 and S6, which are similar to those described above, the threshold U... 关 This may include the re-threshold U 关U and light threshold U 关L There are two scenarios. In subsequent processing, when the error is greater than the light threshold but less than the heavy threshold, the collaborative robot stops and waits for manual intervention to remove the danger (steps S11 and S10). When the error exceeds the heavy threshold, the collaborative robot returns along the original path and alarms, waiting for a safety notification and / or the next operation instruction (steps S9 and S10).

[0074] Steps S7 and S8 involve considering all mechanical joints of the entire collaborative robot as a whole, accumulating the errors of all mechanical joints, and determining whether the error exceeds the threshold U. all (repeated threshold U) allU and light threshold U allL The accumulation method and judgment logic are similar to those described above, and will not be repeated here. The only difference is that the values ​​of the consecutive number of times N3 and the number of times the recording error exceeds the third threshold P3 may be different from the values ​​in step S4.

[0075] The three logics in this embodiment are executed sequentially. That is, if a collision is determined to have occurred in step S4, then it is considered that the collaborative robot has already collided and needs to proceed to the next step of pausing or manual intervention.

[0076] In other embodiments, the above three logics can be executed in parallel, that is, simultaneously determining whether a collision has occurred at a single mechanical joint, an associated joint, and all mechanical joints as a whole, resulting in three collision-free conclusions. Logical operations are then performed on these conclusions to determine whether an alarm should be triggered or whether the operation should be stopped. The logical operations here can be logical AND, logical OR, or a combination of logical AND and logical OR, depending on the usage environment. In a higher safety embodiment, a logical OR operation can be selected; that is, if any one of the three collision-free conclusions indicates a collision, the operation stops and awaits manual intervention.

[0077] For the purpose of ensuring production safety, in steps S3-S4, if the error exceeds the threshold U P' times (P' < P) in N consecutive cyclic comparisons... 单 In such cases, the output torque at output terminal 5 can be reduced to slow down the movement of the corresponding mechanical joint. Similarly, the same slowing-down operation can be performed in steps S5 and S6, as well as steps S7 and S8, except that the values ​​of N, P, and P' can be set to different values.

[0078] Figure 5 This is a curve comparison chart of the actual angle information and the theoretical angle information output by the position encoder in this invention. The solid line represents the actual position information (i.e., encoder angle value) collected by the position encoder 31, and the dashed line represents the position information in the planned path. As can be seen from the figure, at time t0, the dashed and solid lines coincide, meaning that the collaborative robot (or a certain mechanical joint of the collaborative robot) is moving according to the planned path at this time. At times t1 and t2, a significant divergence occurs between the solid and dashed lines, i.e., θ... 1实 θ 2实 , and θ 1设 θ 2设 A significant error occurred, meaning that the collaborative robot (or a particular mechanical joint of the collaborative robot) exhibited abnormal movement, deviating from the planned path. Calculate |θ1set - θ1actual| and |θ2set - θ2actual| to obtain the error at times t1 and t2. Compare this error to a threshold; the result is used to determine whether the collaborative robot has encountered a collision. Specific decision-making principles can be found in relevant... Figure 3 Explanation of the flowchart.

[0079] Back Figure 3 Based on years of practical experience, the threshold in this invention is linearly related to the rotational speed of the motor driving the mechanical joint, that is, the threshold can be calculated by the following formula:

[0080] U 单 =a 单 θ′+b 单 (1)

[0081] Among them, U 单 a represents the threshold of the mechanical joint. 单 and b 单 θ' is an empirical coefficient associated with the mechanical joint, and θ' is the rotational speed of the motor driving the mechanical joint.

[0082] Since the motor speed θ' is not constant, the threshold determined by formula (1) is a dynamic value. The decision based on this dynamic threshold has higher reliability and is more closely related to the current movement speed of the collaborative robot.

[0083] Considering each of the mechanical joints individually, the error and the threshold are compared for each mechanical joint. If the error of any one of the mechanical joints exceeds the threshold U... 单 If the collision occurs, it is determined that a collision has taken place.

[0084] When considering associated joints, the threshold U 关 It is linearly related to the rotational speed of the motor driving the associated joint. For example, the threshold U 关 These values ​​can be comprehensive values ​​derived from experience. That is, a, b, and θ' in formula (1) are comprehensive values, rather than data obtained from actual measurements. For example, the values ​​of a, b, and θ' can be the average values ​​of each mechanical joint, or other statistical values ​​that can be used by those skilled in the art.

[0085] Or, threshold U 关 It could also be an independent threshold U for each of the mechanical joints in the associated joints, taking into account the associated joints. 关 The cumulative value of ; where i represents the sequence number of the i-th mechanical joint in the associated joint, i.e.:

[0086] U 关 =∑U 关i =∑a 关i θ′ i +∑b 关i (2)

[0087] Among them, U 关 U represents the threshold value of the associated joint. 关i a represents the independent threshold of the i-th mechanical joint in the associated joints. 关i and b 关i It is an empirical coefficient related to the i-th mechanical joint, θ′ i The rotational speed of the i-th motor driving the i-th mechanical joint.

[0088] If the sum of the errors of all the mechanical joints in the associated joint exceeds the threshold U 关 If the collision occurs, it is determined that a collision has taken place.

[0089] Taking all the aforementioned mechanical joints into account, the threshold U all This is linearly related to the rotational speed of the motors driving all the aforementioned mechanical joints. For example, similar to the threshold U... 关 The statement, threshold U all It can be a comprehensive value derived from experience.

[0090] Alternatively, the threshold U all It could also be an independent threshold U for each of the mechanical joints when considering all the mechanical joints as a whole.alli The cumulative value, where i represents the sequence number of the i-th mechanical joint, i.e.:

[0091] U all =∑U alli =∑a alli θ′ i +∑b alli (3)

[0092] Among them, U all U represents the threshold value for all the aforementioned mechanical joints. alli a represents the threshold value of the i-th mechanical joint. alli and b alli It is an empirical coefficient related to the i-th mechanical joint, θ′ i The rotational speed of the i-th motor driving the i-th mechanical joint.

[0093] If the sum of the errors of all the aforementioned mechanical joints exceeds the threshold U all If the collision occurs, it is determined that a collision has taken place.

[0094] For the empirical coefficient a in formulas (1), (2) and (3) 单 and b 单 a 关i and b 关i 、,a alli and b alli These are usually different. Below is a set of practical threshold calculation formulas. The empirical coefficients in this example are related to the collaborative robot's weight, arm length, and other conditions; different empirical coefficients should be modified based on multiple trials for different robots.

[0095] ①Each mechanical joint is judged individually:

[0096]

[0097]

[0098] ② Joint determination of the associated joints composed of mechanical joints 42, 43, and 45, where θ′2 is the rotational speed of the motor of mechanical joint 43, θ′3 is the rotational speed of the motor of mechanical joint 45, and θ′4 is the rotational speed of the motor of mechanical joint 47:

[0099] Light threshold <![CDATA[U 关L =0.0009θ′2+0.001θ′3+0.0008θ′4+0.055<!-- 8 --> ]]> Re-threshold <![CDATA[U 关U =0.0016θ′2+0.002θ′3+0.0016θ′4+0.011]]>

[0100] ③ All mechanical joints are judged as a whole, including:

[0101]

[0102] Figure 6This is a block diagram of an exemplary controller 415 in this invention. The controller 415 includes a signal acquisition unit 71, an error calculation unit 72, an accumulation determination unit 73, and an alarm unit 74.

[0103] Signal acquisition unit 71 is used to acquire the real-time position information of the mechanical joint:

[0104] Error calculation unit 72 is used to calculate the error between the real-time location information and the corresponding planned location information in the planned path;

[0105] The cumulative decision unit 73 is used to implement the collision decision process. For example, it can be configured as follows: Figure 3 The method shown is used to make a judgment.

[0106] Alarm unit 74 is used to sound an alarm / sound / electrical means and / or lock the mechanical joint after the cumulative determination unit determines that a collision has occurred, so as to remind the staff to intervene in time and eliminate the danger. It can also use sound / sound / electrical means to indicate that the scheduled work can be restarted after the danger has been eliminated (safety is achieved).

[0107] The present invention also provides a computer-readable storage medium storing instructions that, when executed, enable the computer to implement the collision detection method as described above.

[0108] Numerous specific details are provided in the description provided herein. However, it will be understood that embodiments of the invention may be practiced without these specific details. In some instances, well-known methods, structures, and techniques have not been shown in detail so as not to obscure the understanding of this specification.

[0109] Similarly, it should be understood that, in order to simplify the invention and aid in understanding one or more of the various inventive aspects, features of the invention are sometimes grouped together in a single embodiment, figure, or description thereof in the above description of exemplary embodiments of the invention. However, this disclosure should not be construed as reflecting an intention that the claimed invention requires more features than expressly recited in each claim. Rather, as reflected in the claims, inventive aspects lie in fewer than all features of the single foregoing disclosed embodiment. Therefore, the claims following the detailed description are hereby expressly incorporated into that detailed description, wherein each claim itself is a separate embodiment of the invention.

[0110] Those skilled in the art will understand that modules in the device of the embodiments can be adaptively changed and placed in one or more devices different from that embodiment. Modules, units, or components in the embodiments can be combined into a single module, unit, or component, and further, they can be divided into multiple sub-modules, sub-units, or sub-components. Except where at least some of such features and / or processes or units are mutually exclusive, any combination can be used to combine all features disclosed in this specification (including the accompanying claims, abstract, and drawings) and all processes or units of any method or device so disclosed. Unless expressly stated otherwise, each feature disclosed in this specification (including the accompanying claims, abstract, and drawings) may be replaced by an alternative feature serving the same, equivalent, or similar purpose.

[0111] Furthermore, those skilled in the art will understand that although some embodiments described herein include certain features but not others included in other embodiments, combinations of features from different embodiments are intended to be within the scope of the invention and form different embodiments. For example, in the claims, any of the claimed embodiments can be used in any combination.

Claims

1. A method of detecting a collision, characterized by, A method for detecting whether a collision occurs when an automated device moves along a planned path, wherein the automated device comprises a mechanical joint and a position information acquisition device for acquiring position information of the mechanical joint; The method comprises the following steps: monitoring real-time position information output by the position information acquisition device; calculating an error between the real-time position information and corresponding planned position information in the planned path; if the error exceeds a preset threshold, determining that a collision occurs; otherwise, not considering that a collision occurs, continuing to monitor the real-time position information, and continuing to compare the error and the threshold; wherein the threshold further comprises a heavy threshold and a light threshold, the heavy threshold is greater than the light threshold, when the error exceeds the heavy threshold, the corresponding mechanical joint returns along the original path, when the error exceeds the light threshold but does not exceed the heavy threshold, the corresponding mechanical joint stops.

2. The method of claim 1, wherein, After determining that a collision occurs, the automated device stops moving and sends an alarm.

3. The method of claim 1, wherein, The threshold is linearly related to the rotation speed of the motor driving the mechanical joint.

4. The method of claim 3, wherein, comparing said error and a threshold value U for each of said mechanical joints separately 单 wherein U 单 denotes a threshold value in case of considering each of said mechanical joints separately, and if said error of one of said mechanical joints exceeds said threshold value U 单 a collision is determined to have occurred.

5. The method of claim 3, wherein, Considering the associated joints, a threshold U 关 is linearly related to the rotational speed of the motor driving the associated joint; if the sum of the errors of all the mechanical joints in the associated joint exceeds the threshold U 关 a collision is determined to have occurred.

6. The method of claim 3, wherein, In the overall consideration of all the mechanical joints, threshold U all linearly related to the rotation speed of the motor driving all the mechanical joints; if the sum of the errors of all the mechanical joints exceeds threshold U all , it is determined that a collision has occurred.

7. The method according to any one of claims 1 to 6, wherein Continuously compare the error and the threshold N times, if the comparison result of P times is that the error exceeds the threshold, determine that a collision occurs, otherwise, not consider that a collision occurs, wherein N is a natural number, P≤N.

8. The method of claim 7, wherein, The P times are continuous P times or discontinuous P times.

9. The method of claim 7, wherein, During the continuous N times comparison, when P' times of the comparison result is that the error exceeds the threshold, the movement speed of the mechanical joint is slowed down, wherein P' < P.

10. A controller for detecting a collision, characterized by, A method for detecting whether a collision occurs when an automated device moves along a planned path, wherein the automated device comprises a mechanical joint, and the controller comprises: a signal acquisition unit for acquiring real-time position information of the mechanical joint; an error calculation unit for calculating an error between the real-time position information and corresponding planned position information in the planned path; an accumulated determination unit for determining whether a collision occurs according to the method of any one of claims 3-9.

11. The controller of claim 10, wherein, Further comprising an alarm unit for alarming and / or locking the mechanical joint through sound / light mode after the accumulated determination unit determines that a collision occurs, and prompting through sound / light mode after the danger is removed.

12. A computer readable storage medium, characterized in that, The storage medium stores instructions, when the instructions are executed, the computer implements the method for detecting a collision according to any one of claims 1-9.

13. A mechanical joint, characterized by The mechanical joint implements the method for detecting a collision according to any one of claims 1-9.

14. A robot arm, characterized in that The mechanical arm implements the method for detecting a collision according to any one of claims 1-9.

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