Mechanical arm with a function of slowing down falling and method of slowing down falling

Abstract

The application relates to a mechanical arm with a function of slowing down falling and a method of slowing down falling, which comprises a bus power supply, a motor, a motor driver and a damping module; the input end of the motor driver is connected with the output end of the bus power supply, at least two output ends of the motor driver are connected with at least two input ends of the motor; one input end of the damping module is connected with the bus power supply, the other input end is grounded, at least two input ends of the damping module are connected with at least two input ends of the motor, and a damping loop is formed. The application fully utilizes the current generated when the mechanical arm falls, passively slows down the falling speed, saves energy, and the device is simple and reliable.

Description

Technical Field

[0001] This invention relates to the field of motor control, and particularly to the field of robotic arm control. Background Technology

[0002] In modern industrial robots, collaborative robots, and service robots, many joints are driven by brakeless motors to reduce costs and simplify structure. When the equipment experiences an unexpected power outage or the emergency stop button is pressed, the motor driver stops outputting power, and the motor loses its active torque. Under the influence of gravity, the robotic arm joints will naturally droop, which may cause the end effector to collide with the workpiece or equipment, or even cause personal injury. At the same time, the external force reverses the motor's rotation to generate electricity, and the resulting high back electromotive force may impact the driver's power devices, causing permanent damage.

[0003] In existing technologies, a simple and effective solution is to directly short-circuit the three-phase windings of the motor, utilizing the motor's back electromotive force to generate electromagnetic damping and suppress the fall velocity. However, the damping magnitude of this solution is fixed and cannot be adjusted according to load, inertia, or usage scenario. If the damping is too strong, the joints cannot be moved manually after power failure (or require enormous force), which is detrimental to troubleshooting or posture adjustment; if the damping is too weak, the fall prevention capability is insufficient. Furthermore, the load characteristics of each joint in a multi-joint robotic arm vary greatly, making it difficult for fixed damping to simultaneously meet the requirements of safety and operability.

[0004] Therefore, there is an urgent need for a solution that automatically takes effect when power is off, has adjustable damping strength, and does not interfere with the normal control of the drive. Summary of the Invention

[0005] To provide a basic understanding of some aspects of the disclosed embodiments, a brief summary is given below. This summary is not intended as a general commentary, nor is it intended to identify key / important components or describe the scope of protection of these embodiments, but rather as a prelude to the detailed description that follows.

[0006] This disclosure provides a robotic arm with a fall mitigation function and a fall mitigation method. The present invention makes full use of the current generated when the robotic arm falls to slow down the fall as much as possible and control it within a controllable range. It is simple, reliable and convenient.

[0007] On one hand, this disclosure provides a robotic arm with a fall mitigation function, including a bus power supply, a motor, a motor driver, and a damping module; The input terminal of the motor driver is connected to the output terminal of the bus power supply, and at least two output terminals of the motor driver are connected to at least two input terminals of the motor; one input terminal of the damping module is connected to the bus power supply, the other input terminal is grounded, and at least two input terminals of the damping module are connected to at least two input terminals of the motor, forming a damping circuit. The motor is used to drive the movement of the robotic arm; The motor driver is used to drive the motor to rotate; When the bus power supply is energized, the damping circuit is open. The damping module is used to slow down the descent speed of the robotic arm when the bus power supply fails. When the power supply to the busbar is cut off, the damping circuit forms a closed circuit, and the current generated by the falling robotic arm generates a back electromotive force in the motor through the damping circuit, thereby slowing down the falling speed of the robotic arm.

[0008] Furthermore, the motor is a two-phase motor, including a first input terminal and a second input terminal; The damping module includes at least one first damping unit, and the first damping unit includes at least one first switching unit and at least one first resistor unit; The first input terminal, the first resistor unit, the first switch unit, and the second input terminal are connected in series to form a first damping circuit. When the bus power supply is energized, the switching unit remains in the open state, and the first damping circuit is broken. When the bus power supply fails, the switching unit changes from the open state to the on state, and the first damping circuit is connected.

[0009] Furthermore, the motor is a three-phase motor, including a U-phase input terminal, a V-phase input terminal, and a W-phase input terminal; The damping module includes three damping units, referred to as the second damping unit, the third damping unit, and the fourth damping unit, respectively. Each damping unit includes at least one switching unit and at least one resistor unit. The U-phase input terminal is connected to the second damping unit to form the first branch; The V-phase input terminal and the third damping unit are connected to form a second branch; The W-phase input terminal and the fourth damping unit are connected to form a third branch; The first branch, the second branch, and the third branch are connected in parallel; the damping circuit includes a second damping circuit and a third damping circuit, the first branch, the second branch, and the motor constitute the second damping circuit; the second branch, the third branch, and the motor constitute the third damping circuit; When the bus power supply is energized, the switching unit in the damping unit remains in the open state, and both the second damping circuit and the third damping circuit remain open. When the bus power supply fails, the switching unit in the damping single eye changes from the open state to the on state, and both the second damping circuit and the third damping circuit form a closed circuit.

[0010] Furthermore, the switching unit is a normally closed switch.

[0011] Furthermore, the switching unit is a normally closed electromagnetic relay.

[0012] Furthermore, the second damping unit includes a second switching unit and a second resistor unit, the third damping unit includes a third switching unit and a third resistor unit, and the fourth damping unit includes a fourth switching unit and a fourth resistor unit; the second resistor unit, the third resistor unit, and the fourth resistor unit are adjusted uniformly.

[0013] Furthermore, the damping module also includes a feedback adjustment unit, which includes a backup power supply, a sensor unit, and a control unit; One end of the backup power supply is connected to the output end of the bus power supply, and the other end is connected to the sensor unit and the control unit respectively; the sensor unit is connected to the control unit; the control unit is also connected to the resistor unit; The backup power supply is used to supply power to the sensor unit and the control unit when the bus power supply fails. The sensor unit is used to acquire the angular velocity of the robot arm falling when the bus power supply fails. The control unit is used to compare the angular velocity of the falling robotic arm with a preset value, and dynamically adjust the resistance value of the resistor unit according to the comparison result.

[0014] Furthermore, the step of comparing the descent speed of the robotic arm with a preset value and dynamically adjusting the resistance value of the resistor unit based on the comparison result includes: When the angular velocity is greater than the first preset value, the current resistance value of the resistor unit is reduced to increase the back electromotive force; When the angular velocity is greater than the second preset value and less than the first preset value, the current resistance value of the resistor unit is maintained; When the angular velocity is less than the second preset value, the current resistance value of the resistor unit is increased to reduce the back electromotive force.

[0015] On the other hand, this disclosure also provides a method for mitigating fall based on the above-described robotic arm, including the following steps: Step S1: When the robotic arm is powered on normally, the bus power supply supplies power to the damping module and the motor driver, so that the damping circuit remains open, the motor driver drives the motor normally, and the damping circuit is disconnected. Step S2: When a system power failure or emergency stop occurs, the bus power supply disappears, the damping module loses power, and the damping circuit is completed. Step S3: When the robotic arm joint drives the motor to reverse under the action of gravity, the current generated generates a back electromotive force in the motor through the damping circuit, forming an electromagnetic damping torque that hinders the joint rotation and thus slows down the robotic arm's descent speed.

[0016] Furthermore, it also includes the following steps, Step S4: The sensor unit acquires the real-time angular velocity of the robotic arm, the controller unit compares the falling speed of the robotic arm with the preset value, and dynamically adjusts the resistance value of the resistor unit according to the comparison result. When the angular velocity is greater than the first preset value, the current resistance value of the resistor unit is reduced. When the angular velocity is greater than the second preset value and less than the first preset value, the current resistance value of the resistor unit is maintained; When the angular velocity is less than the second preset value, the current resistance value of the resistor unit is increased.

[0017] Compared with the prior art, the present invention has the following beneficial technical effects: (1) The present invention makes full use of the current generated when the robotic arm falls to passively slow down the falling speed, save energy, and the device is simple and reliable.

[0018] (2) The present invention can dynamically adjust the damping module so that the fall of the robotic arm is in a controllable state. Attached Figure Description

[0019] One or more embodiments are illustrated by way of example with reference to the accompanying drawings. These illustrations and drawings do not constitute a limitation on the embodiments. Elements having the same reference numerals in the drawings are shown as similar elements. The drawings are not to be scaled. And wherein: Figure 1 This is a schematic diagram of the overall structure of this embodiment; Figure 2 This is a schematic diagram of the two-phase motor structure in this embodiment; Figure 3 This is a schematic diagram of the three-phase motor structure in this embodiment. (See attached diagram for details.) 10. Motor; 101. Two-phase motor; 1011. First input terminal; 1012. Second input terminal; 20. Driver; 201. Two-phase motor driver; 203. Three-phase motor driver; 30. Damping module; 301. First damping unit; 302. Second damping unit; 303. Third damping unit; 304. Fourth damping unit; 3011. First switching unit; 3012. First resistor unit; 3021. Second switching unit; 3022. Second resistor unit; 3031. Third switching unit; 3032. Third resistor unit; 3041. Fourth switching unit; 3042. Fourth resistor unit; 40. Feedback adjustment unit; 401. Control unit; 402. Sensor unit; 403. Backup power supply unit. Detailed Implementation

[0020] To provide a more detailed understanding of the features and technical content of the embodiments of this disclosure, the implementation of the embodiments of this disclosure will be described in detail below with reference to the accompanying drawings. The accompanying drawings are for illustrative purposes only and are not intended to limit the embodiments of this disclosure. In the following technical description, for ease of explanation, several details are used to provide a full understanding of the disclosed embodiments. However, one or more embodiments may still be implemented without these details. In other cases, well-known structures and devices may be simplified in their depiction to simplify the drawings.

[0021] The terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this disclosure are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate to implement embodiments of the present disclosure described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion.

[0022] Unless otherwise stated, the term "multiple" means two or more.

[0023] In this embodiment of the disclosure, the character " / " indicates that the objects before and after it are in an "or" relationship. For example, A / B means: A or B.

[0024] The term "and / or" describes an association between objects, indicating that three relationships can exist. For example, A and / or B means: A or B, or A and B.

[0025] The term "correspondence" can refer to an association or binding relationship. The correspondence between A and B means that there is an association or binding relationship between A and B.

[0026] like Figure 1 As shown, the robotic arm in this embodiment includes a bus power supply VCC, a motor 10, a motor driver 20, and a damping module 30. The input terminal of the motor driver 20 is connected to the output terminal of the bus power supply VCC, and at least two output terminals of the motor driver 20 are connected to at least two input terminals of the motor 10; one input terminal of the damping module 30 is connected to the bus power supply VCC, the other input terminal is grounded, and at least two input terminals of the damping module 30 are connected to at least two input terminals of the motor 10 to form a damping circuit. Motor 10 is used to drive the movement of the robotic arm; Motor driver 20 is used to drive motor 10 to rotate; When the bus power supply VCC is energized, the damping circuit ( Figure 1 (Not shown in the image) forms an open circuit; Damping module 30 is used to slow down the descent speed of the robotic arm when the bus power supply VCC loses power; When the bus power supply VCC is de-energized, the damping circuit forms a closed circuit. The current generated by the falling robotic arm forms a back electromotive force in the motor 10 through the damping circuit, thereby slowing down the falling speed of the robotic arm.

[0027] Preferably, this embodiment also includes a feedback adjustment unit 40, which includes a backup power supply 403, a sensor unit 402, and a control unit 401; One end of the backup power supply 403 is connected to the output terminal of the bus power supply VCC, and the other end is connected to the sensor unit 402 and the control unit 401 respectively; the sensor unit 402 is connected to the control unit 401; the control unit 401 is also connected to the resistor unit. Backup power supply 403 is used to supply power to sensor unit 402 and control unit 401 when the bus power supply VCC fails; Sensor unit 402 is used to acquire the angular velocity of the robot arm falling when the bus power supply VCC is lost; The control unit 401 is used to compare the angular velocity of the falling robotic arm with a preset value, and dynamically adjust the resistance value of the resistor unit according to the comparison result.

[0028] The robot arm's descent speed is compared with a preset value, and the resistance value of the resistor unit is dynamically adjusted based on the comparison result, including: When the angular velocity is greater than the first preset value, the current resistance value of the resistor unit is reduced to increase the back electromotive force; When the angular velocity is greater than the second preset value and less than the first preset value, the current resistance value of the resistor unit is maintained; When the angular velocity is less than the second preset value, the current resistance value of the resistor unit is increased to reduce the back electromotive force.

[0029] Preferably, the motor in this embodiment can be a three-phase motor or a two-phase motor. The following will take three-phase motor and two-phase motor as examples for detailed description.

[0030] It should be noted that control unit 401 is a backup controller, not the main controller.

[0031] Figure 2 A schematic diagram of a two-phase motor is shown. Figure 2 As shown, the two-phase motor 101 includes a first input terminal 1011 and a second input terminal 1012; the two-phase driver 201 is connected to the first input terminal 1011 and the second input terminal 1012 respectively. The damping module includes a first damping unit 301, which is connected to the first input terminal 1011 and the second input terminal 1012 respectively; The first damping unit 301 includes a first switching unit 3011 and a first resistor unit 3012; the first input terminal 1011, the first resistor unit 3012, the first switching unit 3011 and the second input terminal 1012 are connected in series to form a first damping circuit; When the bus power supply VCC is energized, the switching unit remains in the open state, and the first damping circuit is broken. When the bus power supply VCC loses power, the switching unit changes from the open state to the on state, and the first damping circuit is completed.

[0032] The first resistor unit is an adjustable resistor, and its resistance value is controlled and adjusted by the control unit 401.

[0033] Figure 3 A schematic diagram of a three-phase motor is shown. Figure 3 As shown, the three-phase motor 102 includes a U-phase input terminal, a V-phase input terminal and a W-phase input terminal; the three-phase driver 202 is connected to the first input terminal 1011 and the second input terminal 1012 respectively; The damping module includes three damping units, referred to as the second damping unit 302, the third damping unit 303 and the fourth damping unit 304, respectively. Each damping unit includes at least one switching unit and at least one resistor unit. The U-phase input terminal is connected to the second damping unit 302 to form the first branch; The V-phase input terminal and the third damping unit 303 are connected to form the second branch; The W-phase input terminal and the fourth damping unit 304 are connected to form the third branch; The first branch, the second branch, and the third branch are connected in parallel; the damping circuit includes the second damping circuit and the third damping circuit. The first branch, the second branch, and the motor 102 constitute the second damping circuit; the second branch, the third branch, and the motor 102 constitute the third damping circuit. When the bus power supply VCC is energized, the switching unit in the damping unit remains in the open state, and both the second and third damping circuits remain open. When the bus power supply VCC loses power, the switching unit in the damping single eye changes from the open state to the on state, and both the second and third damping circuits are connected.

[0034] Preferably, the second damping unit 302 includes a second switching unit 3022 and a second resistor unit 3021, the third damping unit 303 includes a third switching unit 3032 and a third resistor unit 3031, and the fourth damping unit 304 includes a fourth switching unit 3042 and a fourth resistor unit 3041; the second resistor unit 3021, the third resistor unit 3031 and the fourth resistor unit 3041 are uniformly adjusted by the control unit 401.

[0035] Preferably, the switching unit is a normally closed switch; more preferably, the switching unit is a normally closed electromagnetic relay.

[0036] Preferably, this embodiment also provides a working procedure based on the above-described robotic arm, including the following steps: Step S1: When the robotic arm is powered on normally, the bus power supply supplies power to the damping module and the motor driver, so that the damping circuit remains open, the motor driver drives the motor normally, and the damping circuit is disconnected. Step S2: When a system power failure or emergency stop occurs, the bus power supply disappears, the damping module loses power, and the damping circuit is completed. Step S3: When the robotic arm joint drives the motor to reverse under the action of gravity, the current generated generates a back electromotive force in the motor through the damping circuit, forming an electromagnetic damping torque that hinders the joint rotation and thus slows down the robotic arm's descent speed.

[0037] Step S4: The sensor unit acquires the real-time angular velocity of the robotic arm, the controller unit compares the falling speed of the robotic arm with the preset value, and dynamically adjusts the resistance value of the resistor unit according to the comparison result. When the angular velocity is greater than the first preset value, the current resistance value of the resistor unit is reduced. When the angular velocity is greater than the second preset value and less than the first preset value, the current resistance value of the resistor unit is maintained; When the angular velocity is less than the second preset value, the current resistance value of the resistor unit is increased.

[0038] The foregoing description and accompanying drawings fully illustrate embodiments of this disclosure to enable those skilled in the art to practice them. Other embodiments may include structural, logical, electrical, procedural, and other changes. The embodiments represent only possible variations. Individual components and functions are optional unless explicitly required, and the order of operation may vary. Parts and features of some embodiments may be included in or replace parts and features of other embodiments. Moreover, the terminology used in this application is for describing embodiments only and is not intended to limit the claims. As used in the description of embodiments and claims, the singular forms “a,” “an,” and “the” are intended to equally include the plural forms unless the context clearly indicates otherwise. Similarly, the term “and / or” as used in this application means including one or more of the associated listed items and all possible combinations thereof. Additionally, when used in this application, the term "comprise" and its variations "comprises" and / or "comprising" refer to the presence of stated features, integrals, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components, and / or groups thereof. Without further limitations, an element defined by the phrase "comprises a..." does not exclude the presence of other identical elements in the process, method, or apparatus that includes said element. In this document, each embodiment may focus on the differences from other embodiments, and similar or identical parts between embodiments can be referred to mutually. For methods, products, etc., disclosed in the embodiments, if they correspond to the method section disclosed in the embodiments, the relevant parts can be referred to the description of the method section.

[0039] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the embodiments of this disclosure. Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0040] The methods and products disclosed in the embodiments herein (including but not limited to devices, equipment, etc.) can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For instance, the division of units may be merely a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. In addition, the mutual coupling or direct coupling or communication connection shown or discussed may be through some interfaces, and the indirect coupling or communication connection of devices or units may be electrical, mechanical, or other forms. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to implement this embodiment according to actual needs. In addition, the functional units in the embodiments of this disclosure may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

Claims

1. A robot arm having a droop mitigation function, characterized by, Includes bus power supply, motor, motor driver and damping module; The input terminal of the motor driver is connected to the output terminal of the bus power supply, and at least two output terminals of the motor driver are connected to at least two input terminals of the motor; one input terminal of the damping module is connected to the bus power supply, the other input terminal is grounded, and at least two input terminals of the damping module are connected to at least two input terminals of the motor, forming a damping circuit. The motor is used to drive the movement of the robotic arm; The motor driver is used to drive the motor to rotate; When the bus power supply is energized, the damping circuit is open. The damping module is used to slow down the descent speed of the robotic arm when the bus power supply fails. When the power supply to the busbar is cut off, the damping circuit forms a closed circuit, and the current generated by the falling robotic arm generates a back electromotive force in the motor through the damping circuit, thereby slowing down the falling speed of the robotic arm.

2. The robotic arm as described in claim 1, characterized in that, The motor is a two-phase motor, including a first input terminal and a second input terminal; The damping module includes at least one first damping unit, and the first damping unit includes at least one first switching unit and at least one first resistor unit; The first input terminal, the first resistor unit, the first switch unit, and the second input terminal are connected in series to form a first damping circuit. When the bus power supply is energized, the switching unit remains in the open state, and the first damping circuit is broken. When the bus power supply fails, the switching unit changes from the open state to the on state, and the first damping circuit is connected.

3. The robotic arm as described in claim 1, characterized in that, The motor is a three-phase motor, including a U-phase input terminal, a V-phase input terminal and a W-phase input terminal; The damping module includes three damping units, referred to as the second damping unit, the third damping unit, and the fourth damping unit, respectively. Each damping unit includes at least one switching unit and at least one resistor unit. The U-phase input terminal is connected to the second damping unit to form the first branch; The V-phase input terminal and the third damping unit are connected to form a second branch; The W-phase input terminal and the fourth damping unit are connected to form a third branch; The first branch, the second branch, and the third branch are connected in parallel; the damping circuit includes a second damping circuit and a third damping circuit, the first branch, the second branch, and the motor constitute the second damping circuit; the second branch, the third branch, and the motor constitute the third damping circuit; When the bus power supply is energized, the switching unit in the damping unit remains in the open state, and both the second damping circuit and the third damping circuit remain open. When the bus power supply fails, the switching unit in the damping single eye changes from the open state to the on state, and both the second damping circuit and the third damping circuit form a closed circuit.

4. The robotic arm of claim 1, wherein, The switching unit is a normally closed switch.

5. The robot arm of claim 4, wherein, The switching unit is a normally closed electromagnetic relay.

6. The robotic arm of claim 3, wherein, The second damping unit includes a second switching unit and a second resistor unit; the third damping unit includes a third switching unit and a third resistor unit; and the fourth damping unit includes a fourth switching unit and a fourth resistor unit. The second resistor unit, the third resistor unit, and the fourth resistor unit are adjusted uniformly.

7. The robotic arm of claim 1, wherein, The damping module also includes a feedback adjustment unit, which includes a backup power supply, a sensor unit, and a control unit. One end of the backup power supply is connected to the output end of the bus power supply, and the other end is connected to the sensor unit and the control unit respectively; the sensor unit is connected to the control unit; the control unit is also connected to the resistor unit; The backup power supply is used to supply power to the sensor unit and the control unit when the bus power supply fails. The sensor unit is used to acquire the angular velocity of the robot arm falling when the bus power supply fails. The control unit is used to compare the angular velocity of the falling robotic arm with a preset value, and dynamically adjust the resistance value of the resistor unit according to the comparison result.

8. The robotic arm as described in claim 7, characterized in that, The step of comparing the descent speed of the robotic arm with a preset value and dynamically adjusting the resistance value of the resistor unit based on the comparison result includes: When the angular velocity is greater than the first preset value, the current resistance value of the resistor unit is reduced to increase the back electromotive force; When the angular velocity is greater than the second preset value and less than the first preset value, the current resistance value of the resistor unit is maintained; When the angular velocity is less than the second preset value, the current resistance value of the resistor unit is increased to reduce the back electromotive force.

9. A method of sag mitigation for a mechanical arm having a sag mitigation function according to any one of claims 1-8, characterized by, Includes the following steps: Step S1: When the robotic arm is powered on normally, the bus power supply supplies power to the damping module and the motor driver, so that the damping circuit remains open, the motor driver drives the motor normally, and the damping circuit is disconnected. Step S2: When a system power failure or emergency stop occurs, the bus power supply disappears, the damping module loses power, and the damping circuit is completed. Step S3: When the robotic arm joint drives the motor to reverse under the action of gravity, the current generated generates a back electromotive force in the motor through the damping circuit, forming an electromagnetic damping torque that hinders the joint rotation, thereby slowing down the descent speed of the robotic arm.

10. The anti-fall method as described in claim 9, characterized in that, It also includes the following steps: Step S4: The sensor unit acquires the real-time angular velocity of the robotic arm, the controller unit compares the falling speed of the robotic arm with the preset value, and dynamically adjusts the resistance value of the resistor unit according to the comparison result. When the angular velocity is greater than the first preset value, the current resistance value of the resistor unit is reduced. When the angular velocity is greater than the second preset value and less than the first preset value, the current resistance value of the resistor unit is maintained; When the angular velocity is less than the second preset value, the current resistance value of the resistor unit is increased.

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