Robot arm post power down damping droop circuit

Abstract

The utility model relates to a robot arm power -off later damping droop circuit relates to robot technical field, aims at solving the problem of high cost of traditional band brake protection scheme because of no power fast droop easy to cause safety accident after existing robot arm power -off, the circuit includes unidirectional delay power module, LDO power module, threshold comparison module and photoelectric coupling drive module, through threshold comparison module monitoring joint module power supply VCC_MOT voltage, when VCC_MOT disability threshold, trigger photoelectric coupling drive module switch on switch tube, make motor phase line form short circuit loop, utilize electromagnetic induction and produce damping force and hinder arm fast droop, avoid switch tube misdirect on through unidirectional delay power module simultaneously. The utility model does not need software logic, only through hardware realizes the power -off damping of all joint module, and the cost is low, and the response is fast, and the chip is strong in replaceability, and the safety and reliability of robot are improved obviously.

Description

Technical Field

[0001] This utility model relates to the field of robotics technology, and in particular to a damping drooping circuit for a robot arm after power failure. Background Technology

[0002] In the field of robotics applications, the robotic arm is a core execution component, and its normal operation depends on a stable power supply. When the robotic arm encounters a power supply anomaly (such as a sudden power outage), the arm in motion will instantly lose power and droop rapidly and uncontrollably under its own gravity. This situation poses a serious safety hazard: at best, it may cause collision damage to the robotic arm's own structure; at worst, it may injure nearby people or damage surrounding equipment.

[0003] To address these issues, current industry solutions typically involve adding a brake device to each joint module of the robotic arm. For example, a robotic arm with eight degrees of freedom requires eight joint modules; if the robot has two arms, then 16 brake devices are needed. This solution has significant drawbacks: firstly, the hardware cost of the brake devices is high, and a separate installation structure needs to be designed for each joint module, increasing the overall manufacturing cost; secondly, the coordinated control of multiple brake devices relies on complex software logic, which is prone to response delays or malfunctions, reducing system reliability.

[0004] Therefore, there is an urgent need for a low-cost, highly reliable hardware protection solution that does not require complex software control to solve the safety problem of the robot arm drooping rapidly after a power failure. Utility Model Content

[0005] This invention proposes a damping droop circuit for a robot arm after power failure, in order to solve the problems mentioned in the prior art.

[0006] To achieve the above objectives, this utility model provides the following technical solution:

[0007] A damping droop circuit that supports 48V and 24V robot arms after power failure includes a unidirectional delayed power supply module, an LDO power supply module, a threshold comparison module, and an optocoupler drive module.

[0008] The input terminal of the unidirectional delayed power supply module is connected to VCC_12V, and the output terminal is connected to the optocoupler drive module to achieve delayed conduction of VCC_12V.

[0009] The input terminal of the LDO power supply module is connected to the intermediate node of the unidirectional delay power supply module, and the output terminal outputs 5V power supply to provide a stable low voltage for the threshold comparison module and other circuits.

[0010] The threshold comparison module has its first input terminal connected to VCC_5V, its second input terminal connected to the joint module power supply VCC_MOT, and its output terminal connected to the optocoupler drive module to monitor the VCC_MOT voltage and output high and low level signals.

[0011] The control terminal of the optocoupler drive module is connected to the output terminal of the threshold comparison module, and the power terminal is connected to VCC_MOT and ground. It is used to control the connection and disconnection of VCC_MOT and ground according to the signal of the threshold comparison module, so that the motor forms short-circuit damping.

[0012] As a further embodiment of this utility model: the unidirectional delay power supply module includes a diode D1, a capacitor C23, a resistor R18, a resistor R19, and a MOSFET Q4; VCC_12V is connected to one end of the capacitor C23 via the diode D1, and the other end of the capacitor C23 is grounded through the resistor R19. The resistor R18 is connected in parallel across the capacitor C23. The diode D1 is also connected to the source of the MOSFET Q4. The connection point between the capacitor C23 and R18 is connected to the gate of Q4. The drain of Q4 is the output terminal of the unidirectional delay power supply module. The capacitor C23 and R19 form an RC delay circuit. The delay conduction time of Q4 can be adjusted by adjusting the parameters of R19 and C23.

[0013] As a further embodiment of this utility model: the LDO power supply module includes an LDO chip U2, capacitors C10, C14, and C17, and a resistor R20; the IN pin of the LDO chip U2 is connected to VCC_12V, and the IN pin is grounded through capacitor C14; the OUT pin of the LDO chip U2 outputs VCC_5V, and the OUT pin is grounded through C17; the GND pin of U2 is grounded; C10, C14, C17, and C8 are all filter capacitors with capacitance values ​​of 100nF, 100nF, 100nF, and 100nF, respectively.

[0014] As a further embodiment of this utility model: the threshold comparison module includes a comparator U3, a MOSFET Q1, resistors R5, R10, R11, R12, R13, R14, a Zener diode D2, and a capacitor C19; VCC_5V is connected to the positive power supply terminal of comparator U3, and the negative power supply terminal of comparator U3 is grounded; VCC_MOT is grounded through resistors R11 and R10 in series, and the connection point of R10 and R11 is connected to the non-inverting input of comparator U3; VCC_5V is grounded through resistors R12 and R13 in series, and the connection point of R12 and R13 is connected to the inverting input of comparator U3; the output terminal of comparator U3 is connected to the gate of MOSFET Q1 through resistor R14, the source of MOSFET Q1 is grounded, and the drain of MOSFET Q1 is connected to the optocoupler drive module; the Zener diode D2 is connected in parallel across resistor R10, and the capacitor C19 is connected between VCC_5V and ground.

[0015] As a further embodiment of this utility model: the optocoupler driving module includes an optocoupler U1, a MOSFET Q2, resistors R7, R8, and R16; VCC_12V is connected to one end of the input terminal of the optocoupler U1 via resistor R3, the other end of the input terminal of the optocoupler U1 is connected to resistor R5, one end of the output terminal of the optocoupler U1 is connected to resistors R8, R7, and R16, the other end of resistor R8 is connected to the drain of the MOSFET Q4, the other end of the output terminal of the optocoupler U1 is connected to the other end of resistor R17 and ground, the other end of resistor R16 is connected to the gate of the MOSFET Q2, the source of the MOSFET Q2 is grounded, and the drain of Q2 is connected to VCC_MOT.

[0016] As a further aspect of this utility model: the optocoupler U1 is model LTV-217-CS.

[0017] As a further aspect of this utility model: the LDO chip U2 is model number 78L05.

[0018] As a further aspect of this utility model: the comparator U3 is model number TLV3201AIDBVR.

[0019] As a further aspect of this utility model: both MOS transistors Q1 and Q2 are P-MOS transistors.

[0020] As a further embodiment of this invention: the MOS transistor Q4 is an N-MOS transistor.

[0021] The technical effects and advantages provided by this utility model in the above technical solution are as follows:

[0022] Low cost: Only one set of hardware circuitry is needed to protect all parallel joint modules, eliminating the need to add a brake device for each joint, which greatly reduces hardware costs and installation complexity;

[0023] Fast response: Protection is implemented purely with hardware logic, without the need for software judgment and command transmission. The protection response time is <10ms, which is much faster than software control schemes.

[0024] High reliability: The circuit structure is simple, and the core chips are all general-purpose models. There are no imported "bottleneck" chips, which are highly replaceable and reduce supply chain risks.

[0025] High safety: When power is lost, the motor generates a stable damping force to prevent the arm from dropping rapidly, effectively protecting the safety of equipment and personnel;

[0026] Easy to maintain: Fewer circuit components and simpler layout make troubleshooting and repair easier, reducing later maintenance costs;

[0027] Wide compatibility: VCC_MOT is compatible with 48V to 68V, which can meet the power supply requirements of mainstream robot joint modules without the need for specific circuit modifications. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is the circuit diagram of this utility model. Detailed Implementation

[0030] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0031] It should be noted that the terms "vertical," "horizontal," "up," "down," "left," "right," and similar expressions used in this article are for illustrative purposes only and do not represent the only possible implementation.

[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains; the terminology used herein in the description of this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention; the term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0033] This utility model provides, for example Figure 1 The drawing shown is specifically a drive circuit that supports 48V and 24V motors, including a unidirectional delay power supply module, an LDO power supply module, a threshold comparison module, and an optocoupler drive module.

[0034] Unidirectional delayed power supply module, such as Figure 1As shown, VCC_12V conducts unidirectionally through D1. Since C23 needs to be charged, the voltage across R18 equals the voltage across C23, and the voltage rises slowly (the time constant τ of C23 and R19 = R × C). Therefore, the conduction time of Q4 is determined by τ, and the delayed conduction time of Q4 can be adjusted by adjusting the value of RC. When Q4 conducts, VCC_12V (voltage at point A) reaches point B unidirectionally and with a delay through D1 and Q4.

[0035] LDO power supply module such as Figure 1 As shown, VCC_12V is filtered by a capacitor to power the IN pin of chip U2, and the OUT pin of U2 is filtered by a capacitor to output 5V (VCC_5V). The 5V is used to power other chips or provide pull-up voltage to other circuits.

[0036] Threshold comparison circuit such as Figure 1 As shown, U3 is a comparator. The voltage at point F equals the voltage at the inverting input (VCC_5V*R12 / (R12+R13)), and the voltage at point E equals the voltage at the non-inverting input (VCC_MOT*R10 / (R11+R10)). When the voltage at point E is greater than the voltage at point F, comparator U3 outputs 5V, meaning point G equals 5V. When the voltage at point E is less than the voltage at point F, comparator U3 outputs 0V, meaning point G equals 0V. When the voltage at point G equals 5V, Q1 is turned on, meaning point D is pulled low. When the voltage at point G equals 0V, Q1 is turned off, meaning point D is left floating.

[0037] Optocoupler drive circuit, such as Figure 1 As shown, in the U1 optocoupler, R3 and R5 are current-limiting resistors for the U1 input circuit. When the other side of R3 is connected to 12V and the other side of R5 is grounded, the output terminal of U1 is short-circuited, meaning the voltage at point C is pulled low. When the other side of R3 is connected to 12V and the other side of R5 is floating, the output terminal of U1 is open-circuited, meaning the voltage at point C is high (the voltage at point C is the voltage at point B divided by R8 and R7, i.e., the voltage at point C equals half the voltage at point B). When the voltage at point C is high, Q2 conducts; when the voltage at point C is low, Q2 is cut off.

[0038] The hardware logic of this utility model is as follows:

[0039] 1. The voltage at point F equals VCC_5V*R12 / (R12+R13), which is 5V*1K / (1K+1.5K) = 2V. The voltage at point E equals VCC_MOT*R10 / (R11+R10), which is VCC_MOT*1K / (10K+1K). When the voltage at point E equals the voltage at point F (2V), VCC_MOT = 22V. That is, when VCC_MOT is greater than 22V, U3 outputs high; when VCC_MOT is less than 22V, U3 outputs low.

[0040] 2: When the output of point G is high, Q1 is turned on and point D is pulled low. The output of U1 is shorted and point C is pulled low, while Q2 is turned off. When the output of point G is low, Q1 is turned off and point D is left floating. The output of U1 is open and point C is pulled high, while Q2 is turned on.

[0041] Table 1 summarizes the key component status;

[0042] greater than 22V High output Conductivity Output shorting Deadline Less than 22V Low output Deadline Output open circuit Conductivity

[0043] When VCC_12V is powered on, due to the delay in module 1 (the delay time is adjustable), point C of module 4 has already been set (floating or shorted) according to the VCC_MOT voltage when point B receives voltage. This delayed turn-on of Q4 is crucial and prevents Q2 from mis-turning on. Voltage must be supplied to point B only after point C has been set. Therefore, Q2 will only turn on when VCC_MOT is less than 22V. The normal power supply for VCC_MOT is 48V~68V. When VCC_MOT is less than 22V, it indicates module failure, and the voltage begins to drop. When it falls below 22V, VCC_MOT is connected to ground.

[0044] Step 3: Motor Damping

[0045] When an external force rotates a motor, electromagnetic induction generates an induced electromotive force (EMF) (an EMF that opposes the current trend) on the motor's phase lines. When the motor's phase lines are open-circuited, the induced EMF cannot form a loop, thus preventing the formation of an induced current and an electromagnetic field that opposes the current trend. When the motor's phase lines are short-circuited, the induced EMF forms a loop, allowing the formation of an induced current, which in turn generates an electromagnetic field that opposes the current trend. This is the underlying principle of motor damping. Since the power supplies for all robotic arm joint modules are connected in parallel, adding this invention to any node of VCC_MOT will generate a damping effect during the power failure of all joint module motors.

[0046] This invention utilizes hardware circuit protection. When the arm loses power during operation, the motor generates damping, causing it to descend slowly. This significantly increases safety during power outages. Robots or robotic arms using this solution will have better reliability and safety in the robotics field, enhancing their overall competitiveness. Furthermore, this solution achieves power-off protection without requiring software-written judgment logic. The entire system only needs one protection circuit to achieve power-off damping for all joint modules, resulting in lower implementation costs, good maintainability, and strong material versatility, without relying on irreplaceable imported chips.

[0047] It will be apparent to those skilled in the art that this invention is not limited to the details of the exemplary embodiments described above, and that it can be implemented in other specific forms without departing from the spirit or essential characteristics of this invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of this invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within this invention.

[0048] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style of the specification is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment have been appropriately combined to form other embodiments that are easily understood by those skilled in the art.

Claims

1. A damping droop circuit supporting 48V and 24V robot arms after power failure, characterized in that, It includes a unidirectional delay power supply module, an LDO power supply module, a threshold comparison module, and an optocoupler drive module; The input terminal of the unidirectional delayed power supply module is connected to VCC_12V, and the output terminal is connected to the optocoupler drive module to achieve delayed conduction of VCC_12V. The input terminal of the LDO power supply module is connected to the intermediate node of the unidirectional delay power supply module, and the output terminal outputs 5V power supply to provide a stable low voltage for the threshold comparison module and other circuits. The threshold comparison module has its first input terminal connected to VCC_5V, its second input terminal connected to the joint module power supply VCC_MOT, and its output terminal connected to the optocoupler drive module to monitor the VCC_MOT voltage and output high and low level signals. The control terminal of the optocoupler drive module is connected to the output terminal of the threshold comparison module, and the power terminal is connected to VCC_MOT and ground. It is used to control the connection and disconnection of VCC_MOT and ground according to the signal of the threshold comparison module, so that the motor forms short-circuit damping.

2. The damping droop circuit for the robot arm after power failure according to claim 1, characterized in that, The unidirectional delay power supply module includes a diode D1, a capacitor C23, resistors R18 and R19, and a MOSFET Q4. VCC_12V is connected to one end of capacitor C23 via diode D1, and the other end of capacitor C23 is grounded through resistor R19. Resistor R18 is connected in parallel across capacitor C23. Diode D1 is also connected to the source of MOSFET Q4. The junction of capacitor C23 and R18 is connected to the gate of Q4. The drain of Q4 is the output terminal of the unidirectional delay power supply module. The capacitor C23 and R19 form an RC delay circuit. The delay conduction time of Q4 can be adjusted by adjusting the parameters of R19 and C23.

3. The damping drooping circuit for the robot arm after power failure according to claim 2, characterized in that, The LDO power supply module includes an LDO chip U2, capacitors C10, C14, and C17, and a resistor R20. The IN pin of the LDO chip U2 is connected to VCC_12V and is grounded through capacitor C14. The OUT pin of the LDO chip U2 outputs VCC_5V and is grounded through C17. The GND pin of U2 is grounded.

4. The damping droop circuit for the robot arm after power failure according to claim 3, characterized in that, The threshold comparison module includes a comparator U3, a MOSFET Q1, resistors R5, R10, R11, R12, R13, R14, a Zener diode D2, and a capacitor C19. VCC_5V is connected to the positive power supply terminal of comparator U3, and the negative power supply terminal of comparator U3 is grounded. VCC_MOT is grounded through resistors R11 and R10 in series, and the connection point of R10 and R11 is connected to the non-inverting input of comparator U3. VCC_5V is grounded through resistors R12 and R13 in series, and the connection point of R12 and R13 is connected to the inverting input of comparator U3. The output terminal of comparator U3 is connected to the gate of MOSFET Q1 through resistor R14, the source of MOSFET Q1 is grounded, and the drain of MOSFET Q1 is connected to the optocoupler drive module. Zener diode D2 is connected in parallel across resistor R10, and capacitor C19 is connected between VCC_5V and ground.

5. The damping droop circuit for a robot arm after power failure according to claim 4, characterized in that, The optocoupler drive module includes an optocoupler U1, a MOSFET Q2, resistors R7, R8, and R16. VCC_12V is connected to one end of the input terminal of the optocoupler U1 via resistor R3. The other end of the input terminal of the optocoupler U1 is connected to resistor R5. One end of the output terminal of the optocoupler U1 is connected to resistors R8, R7, and R16. The other end of resistor R8 is connected to the drain of the MOSFET Q4. The other end of the output terminal of the optocoupler U1 is connected to the other end of resistor R17 and ground. The other end of resistor R16 is connected to the gate of the MOSFET Q2. The source of the MOSFET Q2 is grounded, and the drain of Q2 is connected to VCC_MOT.

6. The damping droop circuit for a robot arm after power failure according to claim 5, characterized in that, The optocoupler U1 is model LTV-217-CS.

7. The damping droop circuit for a robot arm after power failure according to claim 6, characterized in that, The LDO chip U2 is model number 78L05.

8. The damping droop circuit for a robot arm after power failure according to claim 7, characterized in that, The comparator U3 is model TLV3201AIDBVR.

9. The damping droop circuit for a robot arm after power failure according to claim 8, characterized in that, Both MOSFETs Q1 and Q2 are P-MOS transistors.

10. The damping droop circuit for a robot arm after power failure according to claim 9, characterized in that, The MOS transistor Q4 is an N-MOS transistor.

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