Robot joint module based on shape memory characteristic and Peltier effect

Abstract

The invention belongs to the technical field of manipulators, and discloses a robot joint module based on shape memory characteristics and Peltier effect, comprising: a joint seat, a semiconductor cooler arranged in the joint seat, a power line of the semiconductor cooler being connected with an external power supply; the joint swing arm is hinged to the joint seat, a pulley shaft is arranged in the joint swing arm, and a pulley is arranged on the pulley shaft; the SMA wire is wound on the pulley, the two ends of the SMA wire are fixed to the joint base, the SMA wire is provided with a first section of SMA wire and a second section of SMA wire which are integrally connected, and the cold end and the hot end of the semiconductor cooler are located between the first section of SMA wire and the second section of SMA wire. According to the joint driving module, the joint movement reaction speed of the robot and related parts such as a humanoid dexterous hand can be increased, the system structure is light, and the safety, stability and service life of the system are ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of manipulators, and more particularly to a robot joint module based on shape memory characteristics and Peltier effect. Background Art

[0002] In today's rapidly evolving technological landscape, robotics is making significant strides toward greater intelligence and humanization. The development of anthropomorphic dexterous hands has become a highly anticipated frontier. The humanoid dexterous hand holds immense research value, serving not only as a key breakthrough for achieving refined manipulation in robotics but also as a vehicle for humans to expand their capabilities. By mimicking the complex structure and flexible functions of the human hand, the humanoid dexterous hand is expected to play an irreplaceable role in numerous fields, such as assisting elderly or disabled individuals with mobility difficulties in daily grasping and care tasks at home, performing high-risk tasks in hazardous environments, and achieving high-precision assembly and processing in precision manufacturing.

[0003] As an advanced robotic end-effector, the humanoid dexterous hand offers numerous unique advantages over traditional industrial manipulators. It possesses powerful universal grasping capabilities, capable of grasping objects of various shapes and sizes; a wide grasping range, adaptable to a variety of complex scenarios; a rich variety of grasping gestures, high flexibility, and extremely precise in-hand manipulation. As such, the humanoid dexterous hand has found widespread and in-depth application in key areas such as medical equipment, bioengineering, aerospace, and agricultural production, and the development of related technologies has garnered significant attention and recognition from all sectors of society.

[0004] Currently, common dexterous hands are driven by hydraulics, motors, and pneumatics, but these traditional drive methods have some significant drawbacks. Hydraulically driven dexterous hands (such as CN107791266A - a robotic hydraulically driven five-finger dexterous hand) are typically bulky, increasing the overall weight of the device and making operation and maintenance complex and cumbersome. Motor-driven dexterous hands (such as CN107932536A - a humanoid five-finger dexterous hand device and CN119036496A - a direct-drive dexterous hand) are highly rigid and struggle to achieve the same flexible grip as a human hand, limiting their application in scenarios requiring high grip strength and flexibility. Pneumatically driven dexterous hands (such as CN1651200A - a robotic pneumatic dexterous hand) are often accompanied by high noise levels and lack control precision, which to some extent affects their user experience and scope of application.

[0005] In recent years, the emergence of various new functional materials has provided novel solutions for reducing actuator size. SMA actuators are one such solution. SMA actuators are a fundamentally new type of actuator (e.g., CN108284455A - A Humanoid Dexterous Hand Fingers Actuated by SMA Wire). They integrate sensing, control, energy conversion, and braking, leveraging the unique shape memory effect (SME) of SMA materials to achieve electromechanical energy conversion. SMA actuators are lightweight, have high power density, are simple in structure, and can be easily constructed into microactuators. They offer continuous and smooth motion, operate silently, and are environmentally friendly.

[0006] In the above-mentioned prior art (CN108284455A - A humanoid dexterous hand finger driven by SMA wire), the SMA wire is usually directly connected to a power source for electrical heating, thereby achieving phase change deformation of the SMA wire to drive the finger movement. However, after research, it was found that the method of directly heating the SMA wire with electricity has some defects, such as (1) the cooling and reset of the SMA wire depends on natural cooling, and the cooling process is slow, making it difficult to achieve high reaction speed and high-frequency movement of the finger; (2) when directly heated, the temperature distribution of the SMA wire may be uneven, resulting in inconsistent deformation, and uneven heating may accelerate the initiation of microcracks, causing local stress concentration, causing premature damage to the SMA wire and shortening its service life.

[0007] Therefore, for the SMA drive method, how to improve the driver response speed and ensure the system safety, stability and service life is an urgent problem that those skilled in the art need to solve. Summary of the Invention

[0008] In view of this, the present invention provides a robot joint module based on shape memory characteristics and Peltier effect, which can improve the joint movement reaction speed of robots and related components such as humanoid dexterous hands, achieve lightweight system structure, and ensure system safety, stability and service life.

[0009] In order to achieve the above object, the present invention adopts the following technical solutions:

[0010] A robot joint module based on shape memory characteristics and Peltier effect, comprising:

[0011] A joint seat, wherein a semiconductor cooler is provided in the joint seat, and a power line of the semiconductor cooler is connected to an external power source;

[0012] A joint swing arm, the joint swing arm is hingedly connected to the joint seat, a pulley shaft is provided in the joint swing arm, and a pulley is provided on the pulley shaft;

[0013] An SMA wire is wound on the pulley, and both ends of the SMA wire are fixed on the joint seat. The SMA wire has a first section of SMA wire and a second section of SMA wire that are integrally connected. The hot and cold ends of the semiconductor refrigerator are located between the first section of SMA wire and the second section of SMA wire.

[0014] Through the above technical solution, it can be seen that compared with the prior art, the present invention discloses a robot joint module based on shape memory characteristics and Peltier effect. Under the action of external stress, the SMA wire is repeatedly heated and cooled for certain training so that it has shape memory. When in high temperature state (austenite state), the SMA wire undergoes contraction deformation, and when in low temperature state (martensite state), the SMA wire undergoes elongation deformation. The semiconductor cooler is powered by a power supply. If the side end of the semiconductor cooler close to the first section of SMA wire is the hot end, then the other side end close to the second section of SMA wire is the cold end. Due to the shape memory effect of the SMA wire, when the pre-stretched first section of SMA wire is indirectly heated by the hot end of the semiconductor cooler to above the austenite phase transition temperature, the first section of SMA wire contracts and the second section of SMA wire is stretched. At this time, the joint swing arm realizes a bending action relative to the joint seat. When the joint swing arm needs to be reset, the direction of the current flowing to the semiconductor cooler is changed. At this time, the hot end and the cold end of the semiconductor cooler are exchanged. At this time, the cold end of the semiconductor cooler cools down the first section of SMA wire, causing the first section of SMA wire to quickly cool to the martensitic phase transition temperature and be stretched again. The hot end of the semiconductor cooler heats up the second section of SMA wire, causing the second section of SMA wire to contract. At this time, the joint swing arm realizes the swing back and reset action.

[0015] Therefore, the robot joint module uses a semiconductor cooler to indirectly heat and cool the SMA wire. This avoids the existing problem of uneven temperature distribution and inconsistent deformation caused by direct electrical heating of the SMA wire. Uneven heating can also accelerate the initiation of microcracks, causing local stress concentration, premature damage to the SMA wire, and shortening its service life. In addition, the use of a semiconductor cooler can achieve active cooling of the SMA wire, avoiding the existing problem of slow cooling caused by the SMA wire's reliance on natural cooling, which makes it difficult to achieve high response speed and high-frequency operation of the actuator.

[0016] Furthermore, two hinge plates are fixed on one side end of the joint seat, and two connecting side plates are fixed on one side end of the joint swing arm. A pin shaft is fixed between the two connecting side plates, and the two hinge plates are located between the two connecting side plates, and both hinge plates are rotatably connected to the pin shaft.

[0017] The beneficial effect of adopting the above technical solution is that the pin shaft can be rotated relative to the hinge plate, thereby realizing the swing of the joint swing arm relative to the joint seat, thereby realizing joint movement.

[0018] Furthermore, it also includes a controller and an angle sensor, wherein the inner side of one of the hinge plates is provided with the angle sensor for detecting the rotation angle of the pin shaft, and the controller controls the current parameters of the power supply in real time according to the data of the angle sensor to control the temperature increase or decrease of the semiconductor refrigerator.

[0019] The beneficial effects of adopting the above technical solution are: the angle sensor collects joint angle data (i.e., the pin rotation angle) in real time and transmits it to the controller. The controller compares the actual angle with the target angle and adjusts the temperature control of the semiconductor cooler according to the deviation (for example, if the angle is insufficient, the semiconductor cooler is controlled to heat up and further drive the SMA wire to contract; if the angle is overshoot, the semiconductor cooler is controlled to cool down and allow the SMA wire to stretch and return to its position), forming a closed-loop control, thereby ensuring the accuracy of joint movement.

[0020] Furthermore, the pin shaft is a D-shaped anti-rotation shaft, and the two connecting side plates are each provided with a D-shaped anti-rotation hole, and both ends of the D-shaped anti-rotation shaft are respectively passed through the two D-shaped anti-rotation holes.

[0021] The beneficial effect of adopting the above technical solution is: after the D-shaped anti-rotation shaft and the D-shaped anti-rotation hole are matched, since there is a plane in the matching surface of the two, the anti-rotation effect of the D-shaped anti-rotation shaft can be achieved. That is, during assembly, the D-shaped anti-rotation shaft can be inserted into the D-shaped anti-rotation hole without the need for additional measures to fix the pin shaft, which greatly simplifies the joint structure and assembly process.

[0022] Furthermore, the two SMA wires are arranged at intervals, the two pulleys are arranged at intervals, and the two SMA wires are respectively wound around the corresponding pulleys.

[0023] The beneficial effect of adopting the above technical solution is that the joint is driven by double SMA wires, which can improve the stability of the joint swing arm when swinging.

[0024] Furthermore, a weight-reducing hole is provided on the joint swing arm, and both ends of the pulley shaft are arranged on two opposite side walls of the weight-reducing hole.

[0025] The beneficial effects of adopting the above technical solution are: reducing the weight of the joint swing arm, increasing the lightweight of the joint swing arm, and thus improving the swing effect of the joint swing arm.

[0026] Furthermore, the SMA wire has shape memory properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0028] Figure 1 This is a structural schematic diagram of the first perspective of the three-dimensional structure of a robot joint module based on shape memory characteristics and Peltier effect provided by the present invention.

[0029] Figure 2 This is a structural schematic diagram from a second perspective of the three-dimensional structure of a robot joint module based on shape memory characteristics and Peltier effect provided by the present invention.

[0030] Figure 3 This is a schematic diagram of the main structure of a robot joint module based on shape memory characteristics and Peltier effect provided by the present invention.

[0031] Figure 4 for Figure 3 Schematic cross-section of the middle section AA.

[0032] Figure 5 This is a schematic diagram of the top view of the structure of a robot joint module based on shape memory characteristics and Peltier effect provided by the present invention.

[0033] Figure 6 for Figure 5 Schematic cross-section of the middle section BB.

[0034] Figure 7 This is a schematic diagram of the control part of a robot joint module based on shape memory characteristics and Peltier effect provided by the present invention.

[0035] Figure 8 This is a control logic diagram of a robot joint module based on shape memory characteristics and Peltier effect provided by the present invention. DETAILED DESCRIPTION

[0036] The following describes embodiments of the present invention in detail, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and are not to be construed as limiting the present invention.

[0037] In the description of the present invention, it should be understood that the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as limiting the present invention.

[0038] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature identified as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "plurality" means two or more, unless otherwise specifically defined.

[0039] In the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," "connect," "fixed," etc. should be understood broadly. For example, they may refer to fixed connection, detachable connection, or integration; mechanical connection or electrical connection; direct connection or indirect connection through an intermediate medium; internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0040] like Figures 1-8 As shown, an embodiment of the present invention discloses a robot joint module based on shape memory characteristics and Peltier effect, comprising:

[0041] The joint seat 1 is provided with a semiconductor cooler 2, and the power line 3 of the semiconductor cooler 2 is connected to the external power supply 4;

[0042] The joint swing arm 5 is hingedly connected to the joint seat 1. A pulley shaft 6 is provided in the joint swing arm 5, and a pulley 7 is provided on the pulley shaft 6;

[0043] SMA wire 8, SMA wire 8 is wound on the pulley 7, and both ends of the SMA wire 8 are fixed on the joint seat 1. The SMA wire 8 has a first section of SMA wire 81 and a second section of SMA wire 82 that are integrally connected. The hot and cold ends of the semiconductor cooler 2 are located between the first section of SMA wire 81 and the second section of SMA wire 82.

[0044] The basic principle of the Peltier effect is that when current flows through a conductor, charge carriers jump between energy levels of different materials, resulting in energy exchange. When a charge carrier jumps from a higher energy level to a lower energy level, it releases energy, which manifests as heat release; conversely, when it jumps from a lower energy level to a higher energy level, it needs to absorb energy from the outside world, which manifests as heat absorption. This energy exchange manifests as heat at the joints of the conductors.

[0045] An important application of the Peltier effect is the semiconductor cooler (consisting of a semiconductor cooling chip and a housing), also known as a thermoelectric cooler or a temperature differential cooler. This type of cooler uses the Peltier effect to control the direction of the current, achieving cooling or heating at the junction. Because semiconductor coolers have no refrigerants or moving parts, they have the advantages of precise temperature control, no noise, and high reliability.

[0046] TEC (semiconductor refrigeration) temperature control logic: The TEC controls the temperature rise and fall by controlling the direction and magnitude of the current. To increase the temperature, the current is controlled so that the TEC supplies heat to the SMA. To cool the temperature, the current direction or parameters are changed to allow the TEC to absorb the heat from the SMA, using the temperature change to drive the adjustment of the SMA's strain rate.

[0047] Therefore, the robot joint module of the present invention is designed based on shape memory characteristics and Peltier effect.

[0048] The working principle of the present invention is as follows: the SMA wire is pre-stretched before installation, and power is supplied to the semiconductor cooler through a power supply. If the end of the semiconductor cooler near the first section of the SMA wire is the hot end, then the end of the semiconductor cooler near the second section of the SMA wire is the cold end. Due to the shape memory effect of the SMA wire, when the pre-stretched first section of the SMA wire is indirectly heated to above the austenite phase transition temperature by the hot end of the semiconductor cooler, the first section of the SMA wire contracts and the second section of the SMA wire is stretched. At this time, the joint swing arm realizes a bending action relative to the joint seat. When the joint swing arm needs to be reset, the direction of the current supplied to the semiconductor cooler is changed. At this time, the hot end and the cold end of the semiconductor cooler are exchanged. The cold end of the semiconductor cooler cools the first section of the SMA wire, causing the first section of the SMA wire to quickly cool to the martensitic phase transition temperature and be stretched again. The hot end of the semiconductor cooler heats the second section of the SMA wire, causing the second section of the SMA wire to contract. At this time, the joint swing arm realizes a swing-back reset action.

[0049] The present invention takes into account the drawbacks of fan cooling, which is not only noisy but also occupies a large space. Therefore, the present invention utilizes a semiconductor cooler, which can be applied to space constraints, as the heating and cooling element for the SMA wire. This indirect heating and cooling of the SMA wire by the semiconductor cooler avoids the existing problem of uneven temperature distribution and inconsistent deformation caused by direct heating of the SMA wire. Furthermore, uneven heating can accelerate the initiation of microcracks, causing localized stress concentration, leading to premature failure and shortening the service life of the SMA wire. Furthermore, the semiconductor cooler is suitable for installation in small joint spaces and can also achieve active cooling of the SMA wire, accelerating the transformation of austenite from the SMA wire to martensite, further improving the response speed of the SMA actuator.

[0050] In the above embodiment, two hinge plates 9 are fixed to one side end of the joint seat 1, and one side end of the joint swing arm 5 has two connecting side plates 10, a pin shaft 11 is fixed between the two connecting side plates 10, and the two hinge plates 9 are located between the two connecting side plates 10, and the two hinge plates 9 are both rotatably connected to the pin shaft 11.

[0051] To secure the pin 11 to the connecting side plates 10, the pin 11 is a D-shaped anti-rotation pin. Both connecting side plates 10 are provided with D-shaped anti-rotation holes 101, with the ends of the D-shaped anti-rotation pin respectively inserted into the two D-shaped anti-rotation holes 101. This allows the pin 11 to achieve an anti-rotation effect by utilizing its own structural characteristics.

[0052] In some embodiments of the present invention, a controller 12 and an angle sensor 13 are further included, wherein an angle sensor 13 for detecting the rotation angle of the pin shaft 11 is provided on the inner side of one of the hinge plates 9, and the controller 12 controls the current parameters of the power supply 4 in real time according to the data of the angle sensor 13 to control the temperature increase or decrease of the semiconductor cooler 2.

[0053] In addition, the power supply 4 and the controller 12 of the present invention can be mounted on a robot.

[0054] like Figure 8 As shown, the PID (Proportional-Integral-Derivative) control algorithm can be incorporated into the controller. The proportional term quickly responds to deviations, the integral term eliminates steady-state errors, and the differential term predicts trends. Fuzzy control can also be combined to address complex characteristics such as SMA nonlinearity and TEC thermal inertia, optimizing control accuracy and response speed. Other control algorithms can also be used, such as neural network PID, sliding mode control (SMC), multi-processor predictive control (MPC), integral separation PID, and fuzzy PID.

[0055] In some embodiments of the present invention, there are two SMA wires 8 arranged at intervals, there are two pulleys 7 arranged at intervals, and the two SMA wires 8 are respectively wound around the corresponding pulleys 7.

[0056] In some embodiments of the present invention, a weight-reducing hole 51 is provided on the joint swing arm 5 , and both ends of the pulley shaft 6 are disposed on two opposite side walls of the weight-reducing hole 51 .

[0057] The SMA wire 8 has shape memory properties.

[0058] The joint module of the above embodiment can be used in various robot scenarios such as rehabilitation robots, humanoid robots, humanoid dexterous hands, industrial robots, and service robots.

[0059] The present invention can control the current direction and magnitude of the power supply through a controller, thereby controlling the exchange of the hot and cold ends of the semiconductor refrigerator and the bending angle of the joint.

[0060] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. Reference can be made to the common and similar parts between the various embodiments. For the devices disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple, and the relevant parts can be referred to the method description.

[0061] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A robot joint module based on shape memory characteristics and Peltier effect, characterized in that: include: A joint seat (1), wherein a semiconductor cooler (2) is provided in the joint seat (1), and a power line (3) of the semiconductor cooler (2) is connected to an external power source (4); A joint swing arm (5), the joint swing arm (5) is hingedly connected to the joint seat (1), a pulley shaft (6) is provided in the joint swing arm (5), and a pulley (7) is provided on the pulley shaft (6); An SMA wire (8) is wound around the pulley (7), and both ends of the SMA wire (8) are fixed to the joint seat (1). The SMA wire (8) comprises a first section of SMA wire (81) and a second section of SMA wire (82) that are integrally connected. The hot and cold ends of the semiconductor cooler (2) are located between the first section of SMA wire (81) and the second section of SMA wire (82).

2. A robot joint module based on shape memory characteristics and Peltier effect according to claim 1, characterized in that: Two hinge plates (9) are fixed to one side end of the joint seat (1), and two connecting side plates (10) are provided to one side end of the joint swing arm (5). A pin shaft (11) is fixed between the two connecting side plates (10). The two hinge plates (9) are located between the two connecting side plates (10), and both hinge plates (9) are rotatably connected to the pin shaft (11).

3. The robot joint module based on shape memory characteristics and Peltier effect according to claim 2, characterized in that: It also includes a controller (12) and an angle sensor (13), wherein the angle sensor (13) for detecting the rotation angle of the pin shaft (11) is provided on the inner side of one of the hinge plates (9), and the controller (12) controls the current parameters of the power supply (4) in real time according to the data of the angle sensor (13) to control the temperature increase or decrease of the semiconductor refrigerator (2).

4. A robot joint module based on shape memory characteristics and Peltier effect according to claim 2 or 3, characterized in that: The pin shaft (11) is a D-shaped anti-rotation shaft, and the two connecting side plates (10) are each provided with a D-shaped anti-rotation hole (101), and the two ends of the D-shaped anti-rotation shaft are respectively passed through the two D-shaped anti-rotation holes (101).

5. A robot joint module based on shape memory characteristics and Peltier effect according to any one of claims 1 to 3, characterized in that: The two SMA wires (8) are arranged at intervals, the two pulleys (7) are arranged at intervals, and the two SMA wires (8) are respectively wound around the corresponding pulleys (7).

6. A robot joint module based on shape memory characteristics and Peltier effect according to any one of claims 1 to 3, characterized in that: A weight-reducing hole (51) is provided on the joint swing arm (5), and both ends of the pulley shaft (6) are arranged on two opposite side walls of the weight-reducing hole (51).

7. A robot joint module based on shape memory characteristics and Peltier effect according to any one of claims 1 to 3, characterized in that: The SMA wire (8) has shape memory properties.

8. A robot joint module based on shape memory characteristics and Peltier effect according to any one of claims 1 to 3, characterized in that: Joint modules can be used in a variety of robot scenarios including rehabilitation robots, humanoid robots, humanoid dexterous hands, industrial robots, and service robots.

Images