Drive device

Abstract

The transmission device (112) is designed as a tandem elastic transmission (SEA) having a brushless motor (13) which transmits rotation and torque to an output shaft (134) of the drive device (112) via a gearbox (132). One or more torsion springs (136) connect the motor (130) and the gearbox (132) to a frame (128) of the drive (112). The reaction torque generated by the gearbox (132) and the electric machine (130) may cause deformation of the torsion spring (136). The deformation is then read by a rotary encoder module (144), thereby calculating the torque generated by the drive device (112).

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application incorporates by reference the following documents: International Application No. PCT / IB2014 / 062735, filed on June 30, 2014, published as WO 2015 / 001469 A1 on January 8, 2015; International Application No. PCT / IB2016 / 050639, filed on February 8, 2016, published as WO 2016 / 128877 A1 on August 18, 2016; International Application No. PCT / IB2019 / 053598, filed on May 2, 2019, published as WO 2019 / 211791 A1 on November 7, 2019; International Application No. PCT / US2020 / 029573, filed on April 23, 2020, published as WO 2020 / 219712 A1 on October 29, 2020 A1; and international application PCT / IB2021 / 058139 filed on September 7, 2021, published as WO 2022 / 053934 A1 on March 17, 2022.

[0003] This application also incorporates by reference U.S. Provisional Patent Application No. 63 / 421,862, filed on November 2, 2022, entitled “ACTIVE PELVIC ORTHOSE INCLUDING A PHYSICAL HUMAN-MACHINE INTERFACE.” Similarly, this application also incorporates by reference PCT Application No. 63 / 421,862, filed on November 2, 2022, entitled “ACTIVE PELVIC ORTHOSE INCLUDING A PHYSICAL HUMAN-MACHINE INTERFACE.” Technical Field

[0004] The present invention relates to a drive system for a wearable robot, and in particular to a drive system for an active pelvic orthosis that can be used to support the hip. Background Art

[0005] Movement disorders associated with aging present challenges for individuals requiring assistance with mobility, particularly walking and activities of daily living. Robotic orthoses and exoskeletons offer a promising solution for assisting the elderly and others with mobility impairments. These orthoses typically have an anthropomorphic appearance and are worn by the patient. To achieve active assistance, such robotic orthoses may include a drive mechanism that generates and transmits mechanical power to the affected joint.

[0006] An example of a robotic orthosis is an active pelvic orthosis (APO), a wearable orthosis designed to improve gait efficiency, particularly in situations affected by hip injuries. The APO, which may be of the type described in WO 2016 / 128877, employs a complex system of connectors, actuators, and other components to align the body's flexion-extension axis with a control system, thereby assisting the user's hip abduction-adduction rotation and internal rotation-external rotation.

[0007] Known drive mechanisms used in robotic orthoses include electric, pneumatic, hydraulic, and passive actuators. Of note, the series elastic actuator (SEA) has been used in various applications. The characteristic of an SEA actuator is that a passive elastic element is connected in series with the motor and gearbox, with the elastic element positioned between the gearbox and the load.

[0008] The basic design of the SEA can be seen in Figures 1A and 1B of this article and will be described in more detail below. Under normal static conditions, the torque (Δτ) exchanged between the SEA and the load can be calculated by multiplying the deflection of the torsion spring (Δθ) by the spring stiffness (K), yielding the following formula:

[0009] Δτ=k×Δθ.

[0010] If the SEA generates an output torque (i.e., an applied force) (Δτ), the load generates a reaction force equal in magnitude but opposite in direction to the applied force. This output torque (Δτ) does not cause motion of the SEA or the load; instead, the output torque (Δτ) causes a torsional deformation (Δθ) of the spring according to the following formula:

[0011] Δτ / k=Δθ=Δθ1-Δθ2.

[0012] If the output torque (Δτ) cannot be measured directly, it can be estimated when the spring stiffness (K) is known and the deformation values (Δθ1, Δθ2) are measured by the encoder module.

[0013] The elastic element of an SEA forms a compliant mechanical interface between the motor and the load. Elasticity generally reduces the corresponding inertia and improves shock absorption and energy storage capabilities. However, a key issue when using this type of actuator is the selection and construction of the elastic element. Disadvantages of using a traditional SEA include reduced positioning bandwidth, an increased number of mechanical components, and increased overall weight. The SEA-load interaction in a traditional SEA cannot be measured directly; instead, if the stiffness of the elastic element is known and the elastic deformation of the spring can be measured, the SEA-load interaction can be estimated indirectly. Therefore, improvements to the drive unit are needed.

[0014] For the elastic elements of an SEA, it is desirable to have low manufacturing costs, low weight, and a small footprint, especially when it is to be integrated with wearable robotics. Furthermore, since the elastic elements should be designed according to fatigue criteria, the SEA should be able to accurately track the force and control the torque of the system, which requires the elastic element's stiffness to be within a specified range. Finally, the design of the elastic element and SEA should ensure a well-defined and repeatable assembly process. Therefore, the purpose of the actuator device described in the present invention is to provide an improved SEA in which the elastic element has these desired properties.

[0015] The subject matter claimed herein is not limited to embodiments that address any disadvantages, nor is it limited to embodiments that are used only in such environments as described above. Instead, this background technology only illustrates some example situations in a certain technical field in which certain embodiments of the drive apparatus described herein can be applied. Summary of the Invention

[0016] Embodiments of the devices, systems, and methods disclosed herein relate to a drive device or drive unit having an improved series elastic actuator (SEA). The present invention relates to a drive device, drive system, and method for generating assistive torque for users of active pelvic orthoses (APOs). The present invention aims to improve upon the aforementioned prior art solutions, particularly with regard to ergonomics and ease of use, such as by reducing weight, achieving a compact design, and utilizing customized elastic elements acting as torsion springs to connect the motor and gearbox to the frame of the drive device.

[0017] The drive unit is a highly customized, rotary, electric SEA. It features a brushless motor that transmits rotation and torque to the drive unit's output shaft via a gearbox. One or more torsion springs or elastic elements connect the motor and gearbox to the drive unit's frame. The reaction torque generated by the gearbox and motor causes deformation in the torsion springs. A rotary encoder module then reads this deformation to calculate the torque generated by the drive unit.

[0018] One or more torsion springs provide a compact torsionally elastic assembly with linear angle / torque characteristics that are independent of the direction of rotation. The one or more torsion springs prevent unintended contact between components, provide high engagement with the connected element, and achieve a high transmittable torque relative to their weight and overall size. The one or more torsion springs are designed based on fatigue criteria. Unlike conventional devices, where the torsion spring is positioned between the gearbox and the load, it is mounted on the opposite end from the load. This characteristic is also maintained in the design of the elastic element described below.

[0019] Using more than one torsion spring can reduce the manufacturing cost of the drive device.The fastening mechanism between the torsion springs can be oriented in the axial or radial direction of the torque output axis of the drive device.

[0020] Furthermore, the fastening mechanism, oriented in the radial direction of the drive unit, can interrupt the chain of axial relative positions of the various components. In fact, the sequence of mating components (each with its own dimensional tolerances) is provided with clearance by the holes in the torsion spring designed to accommodate the screws used to attach the springs. Therefore, during assembly, only the necessary elements of the sequence or chain of mating components determine the final axial relative positions of the components.

[0021] These and other aspects of the described drive apparatus and the operation and function of the associated structural elements and combinations of parts will become more apparent upon consideration of the following description and appended claims with reference to the accompanying drawings, all of which constitute a part of this specification.

[0022] To summarize the disclosed drive device, certain aspects, advantages, and novel features of the drive device are described herein. It should be understood that not all of these advantages are necessarily achieved according to any particular embodiment of the drive device. Thus, the drive device may be embodied or implemented in a manner that achieves or optimizes one advantage or group of advantages taught herein without necessarily achieving other advantages taught or suggested herein.

[0023] Glossary

[0024] The term "approximately" refers to a value that is within a statistical range of one or more values, for example, within the context of a stated length, distance, weight, height, angle, or force.

[0025] The term "encoder" has its conventional and customary meaning to those skilled in the art and, unless otherwise specified, refers to both absolute and incremental encoders. An encoder may include a device or sensor for detecting position. Encoders may be mechanical, optical, magnetic, or electromagnetic induction.

[0026] The term "elastic" refers to the ability to recover size and shape after deformation.

[0027] The term "gearbox" or "gear train" has a conventional meaning and refers to a series of gears designed to achieve a specific overall gear ratio. The gearbox described herein is based on harmonic drive and can act as a speed reducer and torque multiplier.

[0028] As used herein, the terms "rigid," "flexible," "compliant," and "elastic" may distinguish between partial properties of certain features in a drive system. The term "rigid" refers to a component of a drive system (e.g., a frame) that is substantially inflexible. In the context of "rigid" features, it is understood that these features do not lose their overall shape when subjected to a force and may break when a sufficient force is applied to bend them. The term "flexible" refers to the ability of a feature to bend repeatedly, such that the feature can be bent into a non-retaining shape, or the feature does not retain its overall shape but continues to deform when subjected to a force. The term "elastic" refers to the ability of such a flexible feature to substantially return to its original overall shape without permanent deformation. For the term "semi-rigid," the term may refer to the property of a support element or housing that provides support and exists independently; however, such a support element or housing may be flexible or elastic.

[0029] The term "substantially" or "essentially" means that the characteristics, parameters, or values ​​proposed do not need to be achieved precisely, but may have deviations or changes, such as tolerances, measurement errors, measurement precision limitations, and other deviation factors known to those skilled in the art, as long as the degree of these deviations or changes does not eliminate the effect that the feature is intended to provide. The term "substantially" or "essentially" refers to ±10% in some embodiments, ±5% in some embodiments, and ±1% in some embodiments.

[0030] The term "user" refers to the person who uses the active pelvic orthosis. The user can be a patient or an operator.

[0031] It should be understood that unless a term has been defined to have the described meaning, the meaning of the term is not limited, either explicitly or indirectly, beyond its original or ordinary meaning. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] This document describes certain embodiments, some examples of which are shown in the accompanying drawings. These drawings are intended to be illustrative and not limiting. Although this document generally describes these embodiments, it should be understood that the scope of the present invention is not limited to these specific embodiments. The drawings are not necessarily drawn to scale.

[0033] Other characteristics and advantages of the invention will become apparent from the following description with reference to the accompanying drawings, which are given by way of non-limiting example only.

[0034] FIG1A shows a block diagram of a conventional series elastic actuator.

[0035] FIG1B shows a cross-sectional view of a conventional series elastic actuator.

[0036] Figure 2 Shown is a perspective view of an exemplary wearable robotic device configured as an active pelvic orthosis.

[0037] Figures 3A to 3C Shows Figure 2 Cross-sectional view of the auxiliary unit of the active pelvic orthosis.

[0038] Figure 3D Shows Figure 2 sectional view of an active pelvic orthosis in FIG, which comprises a transmission unit with a crank-connecting rod system.

[0039] Figure 4 A cross-sectional view of an embodiment of a drive device according to the present invention is shown.

[0040] Figure 5A A block diagram of an embodiment of the described drive device is shown, which has an elastic element at the beginning of the chain.

[0041] Figures 5B to 5C Shows the Figure 5A Perspective and cross-sectional views of the relevant drive device.

[0042] Figures 6A to 6C Shows the Figure 5A Perspective and cross-sectional views of a related drive arrangement with an elastic element directly connected to the front frame of a series elastic drive.

[0043] Figure 7A A block diagram of one embodiment of the disclosed drive device is shown having a plurality of elastic elements connected in series at the beginning of a chain.

[0044] FIG. 7B to FIG. 7C Shows the Figure 7A Perspective and sectional views of a corresponding drive device with an axial connection between at least one elastic element and a rotary drive.

[0045] Figures 8A to 8C Shows the Figure 7A Perspective and sectional views of a corresponding drive device with a radial connection between at least one elastic element and a rotary drive.

[0046] Figure 9A A block diagram of one embodiment of the disclosed drive device is shown having multiple elastic elements connected in series and in parallel at the beginning of the strip.

[0047] Figures 9B to 9D Shows the Figure 9A Perspective and cross-sectional views of a related drive device, the components of which have close dimensional tolerances.

[0048] FIG. 10A to FIG. 10B Shows the Figure 9A Perspective and cross-sectional views of a related drive device, wherein at least one elastic element has a small axial dimension.

[0049] FIG. 11A to FIG. 11B Shows Figure 2 Cross-sectional view of a variant of the auxiliary unit of the active pelvic orthosis.

[0050] Figure 12A Shown Figure 11A Cross-sectional view of the auxiliary unit in .

[0051] Figure 12B Shown Figure 10A Cross-sectional view of the auxiliary unit in .

[0052] FIG. 13A to FIG. 13B Shows Figure 2 Cross-sectional view of another variant of the auxiliary unit of the active pelvic orthosis.

[0053] Figure 14 A block diagram of another embodiment of a drive device is shown. DETAILED DESCRIPTION

[0054] Various embodiments of the present invention may be better understood from the following description and accompanying drawings, in which like reference numerals refer to like elements.

[0055] A. Theoretical Background

[0056] 1A and 1B illustrate the design of a conventional series elastic actuator (SEA) system 10. FIG1A shows a rotary actuator 40 comprising a motor 20 and a gearbox 30. An elastic element 50 is connected in series with the motor 20 and the gearbox 30, and is positioned between the rotary actuator 40 and a load 60.

[0057] FIG1B shows a cross-sectional view of the SEA system 10 of FIG1A , which is supported by two frame members 70. Under normal static conditions, the torque (Δτ) exchanged between the SEA system 10 and the load 60 can be calculated by multiplying the deformation (Δθ) of the elastic element 50 by the stiffness (K) of the elastic element 50, resulting in the following formula:

[0058] Δτ=k×Δθ.

[0059] If the SEA generates an output torque (i.e., an applied force) (Δτ), the load 60 generates a reaction force equal in magnitude but opposite in direction to the applied force. Such an output torque (Δτ) does not cause motion of the SEA system 10 or the load 60; instead, the output torque (Δτ) causes a torsional deformation (Δθ) of the elastic element 50 according to the following formula:

[0060] Δτk=Δθ=Δθ1-Δθ2。

[0061] If the output torque (Δτ) cannot be directly measured, it can be estimated when the stiffness (K) of the elastic element 50 is known and the deformation values (Δθ1 , Δθ2 ) are measured by the encoder module 80 .

[0062] As described above, the elastic element 50 of the SEA system 10 forms a compliant mechanical interface between the motor 20 and the load 60. However, the SEA-load interaction in the conventional SEA system 10 cannot be directly measured; instead, if the stiffness of the elastic element 50 is known and if the elastic deformation of the elastic element 50 can be measured, the SEA-load interaction can be indirectly calculated.

[0063] B. Detailed description of various embodiments

[0064] Although certain illustrative embodiments are shown in the accompanying drawings and below, the present invention may also adopt various modifications and alternative structures. The dimensions, angles, and curvatures described herein are all to be understood as exemplary and are not necessarily drawn to scale. However, it should be understood that the present invention is not intended to be limited to the specific embodiments described, but rather to encompass all modifications, alternative structures, combinations, and equivalents falling within the spirit and scope of the present invention. In the various drawings, similar elements have similar reference numerals. The reference numerals used herein are for ease of description only and therefore do not limit the scope of protection of the embodiments.

[0065] Figure 2An exemplary active pelvic orthosis (APO) 100 is shown for assisting a user with lower limb mobility. APO 100 includes at least one assistive unit 102 for generating assistive forces for flexion and extension along a first axis I1 corresponding to one or both hips of the user. A housing 103 of assistive unit 102 houses various components for providing torque around the user's hip flexion and extension joints. APO 100 includes a rear housing or backpack 106 for housing electrical components, such as a power supply and a computing unit. Backpack 106 may also be equipped with a width adjustment system and / or an orientation locking system for assistive unit 102. Assistive unit 102 is connected to backpack 106 via a connecting element 104. Connecting element 104 couples assistive unit 102 to backpack 106 and may also be used to secure electrical wiring and / or a power source (e.g., a battery). APO 100 includes a waist belt 110 for connection to the user and at least one thigh connector 108. The waist belt 110 provides connection points to the user's abdomen and waist, and the thigh links 108 provide connection points to the user's thighs. The thigh links 108 are rotatably connected to the housing 103 via connection attachments 109, which are substantially aligned with the first axis I1 to allow flexion and extension of the user's lower limbs.

[0066] Figures 3A to 3C Shows Figure 2 1 is a cross-sectional view of the auxiliary unit 102 in FIG. The auxiliary unit 102 generates torque for the flexion and extension movement of the user's hip. The auxiliary unit 102 includes a driver or drive unit 112 and a transmission unit 114 located in a housing 103. The auxiliary unit 102 is positioned on the right and / or left side of the user's body. In one embodiment, the second axis I2 is a rotational output axis, preferably aligned with the user's hip flexion and extension axis and parallel to the first axis I1. The auxiliary unit 102 transmits the auxiliary torque to the user's legs through the thigh connector 108. As shown in FIG. Figure 3A to Figure 3B As shown, the auxiliary unit 102 is arranged on a first axis I1 and a second axis I2, wherein the first axis corresponds to the position of the drive unit 112 and the second axis I2 roughly corresponds to the user's hip flexion and extension joint. The transmission unit 114 transmits motion and torque between the two axes I1 and I2, wherein the first axis I1 corresponds to the output axis of the auxiliary unit 102 and the second axis I2 corresponds to the input axis of the auxiliary unit. The joint encoder 116 can measure the rotation of the thigh link 108 around the first axis I1 oriented in line with the user's thigh. The joint encoder 116 can be magnetic and used as a redundant safety mechanism.

[0067] The transmission unit 114 includes a first timing pulley 118, a second timing pulley 120, and a synchronous timing belt 122. In one embodiment, the center-to-center distance between the timing pulleys 118 and 120 of the transmission unit 114 is fixed. In another embodiment, the center-to-center distance between the timing pulleys 118 and 120 of the transmission unit 114 is adjustable. The transmission ratio of the transmission unit 114 can also be equal to or different from 1:1. The timing belt 122 can be constructed of a stain-resistant and wear-resistant polyurethane structure with a carbon fiber tension cord. The first and second timing pulleys 118, 120 can be constructed of nylon to provide excellent mechanical properties, fatigue resistance, and reduced weight. In one embodiment, the first timing pulley 118 serves as the driving timing pulley and can be coaxial with the drive unit 112 on the second axis I2. The second timing pulley 120 serves as the driven timing pulley and can be coaxial with the attachment 109 on the first axis I1. The transmission unit 114 helps protect the motor axis I1 from the load motions generated by the interaction between the thigh link 108 and the user's leg. In addition, the transmission unit 114 allows the relatively bulky components to be placed near a certain area of the user's body (i.e., the outer portion of the gluteal muscles) to avoid creating a large outer footprint.

[0068] Figure 3D Assist unit 102 is shown, having a transmission unit 114 comprising a crank 124 and a rod 126. Transmission unit 114 can be designed to transmit mechanical power between two parallel axes I1 and I2 using various methods (e.g., a four-bar linkage or chain drive system). In another embodiment, assist unit 102 of APO 100 may not utilize a transmission unit 114 operating along two axes I1 and I2, but instead may include drive unit 112 located along the same axis I1 as thigh link 109. Thus, drive unit 112 can directly engage the user's hip flexion and extension axis, or first axis I1.

[0069] Figure 4 A cross-sectional view of one embodiment of the drive unit 112 is shown. Drive unit 112 is a custom, rotary, electric, series-type elastomeric actuator powered by a brushless motor 130. Motor 130 transmits rotation and torque to an output shaft 134 of drive unit 112 via a gearbox 132. Gearbox 132 acts as a speed reducer and torque amplifier, and is based on harmonic drive.

[0070] The combination of elastic elements or torsion springs 138, 140, 142 are connected together by fasteners 141 as a unified elastic assembly 135 and connect the motor 130 and gearbox 132 to the frame 128 in a compliant manner. The fasteners 141 can be screws, bolts, clips and / or other rigid connecting elements. The reaction torque generated by the gearbox 132 and motor 130 causes the elastic elements 138, 140, 142 to deform, wherein the deformation is read by the encoder module 144. The encoder module 144 includes an encoder ring 146 connected to the input flange or first flange 154 and an encoder read head 148 connected to the output flange or second flange 156, which will be referred to below. Figure 6C The encoder module 144 can calculate the torque generated by the drive unit 112 based on the stiffness values of the elastic elements 138 , 140 , 142 .

[0071] Figure 5A The overall structure of the drive unit 112 is shown, along with the integrated torsion spring 136 relative to the other components of the drive unit 112. Advantageously, the torsion spring 136 is located at the beginning of the drive unit 112, opposite the load 150, rather than between the gearbox 132 and the load 150. The dashed line connecting the motor 130 and the torsion spring 136 indicates that the interaction between these two components is negligible because the interaction between the motor 130 and the torsion spring 136 is approximately two orders of magnitude smaller than the interaction between the gearbox 132 and the torsion spring 136.

[0072] Figures 5B to 5C An embodiment of a drive unit 112 is shown. Drive unit 112 includes a torsion spring 136 in accordance with WO 2015 / 001469 A1, which is incorporated herein by reference. In one embodiment, torsion spring 136 is shaped as a parallelepiped, having a linear segment 143 extending parallel to the second axis I2. This provides a compact torsional elastic element with linear angle / torque characteristics that are independent of rotational direction, prevents unintended contact between its components, provides high engagement with connected components, and achieves a high transmittable torque relative to its weight and overall size. In one embodiment, the stiffness of torsion spring 136 is preferably between 100 Nm / rad and 5000 Nm / rad, a range that enables precise and stable torque control of drive unit 112. In one exemplary embodiment, the stiffness of torsion spring 136 is approximately 200 Nm / rad. The expected stiffness value of the torsion spring 136 depends on various aspects, such as the resolution of the encoder module 144 used to read the deformation of the torsion spring 136 .

[0073] A fundamental variable in achieving the desired properties of the torsion spring 136 lies in the material or materials used; the most suitable materials are metals commonly used in mechanical structures. These include steel, aluminum alloys, and titanium alloys. First, the Young's modulus of the selected material can be determined, which is an essential parameter for achieving the desired stiffness properties of the torsion spring 136. In addition to the desired stiffness, the choice of material to be used is directly dependent on the size of the mechanical load 150 that the torsion spring 136 should be able to withstand and the degree of compactness that is desired to be achieved. In addition, Figures 5B to 5C The assembly of the drive unit 112 and the torsion spring 136 in the embodiment shown is well defined and repeatable.

[0074] Drive unit 112 includes a first frame 128 and a second frame 129 for rigidly supporting components of drive unit 112 and housing 103 of auxiliary unit 102. Torsion spring 136 has a first flange 154 connected to motor housing 152 and a second flange 156 connected to second frame 129. Drive unit 112 also includes an encoder module 144 having an encoder ring 146 and a read head 148. Encoder module 144 directly detects relative rotation of second flange 156 of torsion spring 136 relative to first flange 154 about second axis I2, without using frames 128 and 129 as angular reference points. Encoder ring 146 is connected to first flange 154 of torsion spring 136, and encoder read head 148 is connected to second flange 156 of torsion spring 136. Motor housing 152 houses brushless motor 130, which is connected to gearbox 132. Gearbox 132 extends through first frame 128 to engage load 150. Figures 5A to 5C The load 150 shown is associated with the mechanical system or transmission unit 114 driven by the drive unit 112. Compared with the conventional SEA system 10 shown in FIG. 1B , Figures 5B to 5C The embodiment of the drive unit 112 in FIG. 1 reduces weight and space by providing a single encoder module 144 and two frames 128 , 129 .

[0075] Figures 6A to 6C Another embodiment of the drive unit 112 is shown. As shown, an integral torsion spring 136 is located at the starting end of the drive unit 112 opposite the load 150, rather than between the gearbox 132 and the load 150. The output flange or second flange 156 of the torsion spring 136 is directly connected to the single front frame 128 of the drive unit 112. The input flange or first flange 154 is directly connected to the gearbox 132. The torsion spring 136 surrounds the motor 130 circumferentially relative to the second axis I2 and includes a linear segment 143 extending parallel to the second axis I2. Compared to the conventional SEA system 10 shown in FIG. 1B , Figures 6A to 6CThe embodiment of the drive unit 112 in FIG. 1 further reduces weight and space by using a single frame 128. Figure 6C As shown, the spring's torsion (Δθ) can be measured by an encoder module 144 having an encoder ring 146 rigidly connected to the first flange 154, while a readhead 148 is rigidly connected to the spring's output flange. According to the data sheet, encoder ring 146 and readhead 148 function properly if their axial distance, or gap 149, is within a specified range. In one embodiment, gap 149 is between 0.05 mm and 0.35 mm.

[0076] Figure 7A The overall structure of the drive unit 212 is shown with a first torsion spring 236 and a second torsion spring 237. Advantageously, the first torsion spring 236 and the second torsion spring 237 are connected in series and are located at the starting end of the drive unit 212 opposite the load 250, rather than between the gearbox 232 and the load 250. The dashed line connecting the motor 230 and the first torsion spring 236 and the second torsion spring 237 indicates that the interaction between these components is negligible because the interaction between the motor 230 and the first torsion spring 236 and the second torsion spring 237 is approximately two orders of magnitude smaller than the interaction between the gearbox 232 and the first torsion spring 236 and the second torsion spring 237.

[0077] FIG. 7B to FIG. 7C An embodiment of a drive unit 212 is shown. The drive unit 212 includes a first torsion spring 236 and a second torsion spring 237, wherein the first torsion spring 236 and the second torsion spring 237 form a unified elastic assembly 235. The equivalent stiffness value of the unified elastic assembly 235 is preferably between 100 Nm / rad and 5000 Nm / rad, which allows for precise and stable torque control of the drive unit 212. In an exemplary embodiment, the stiffness value of the elastic assembly 235 is approximately 5000 Nm / rad. The desired stiffness value of the elastic assembly 235 depends on various factors, such as the resolution of the encoder module 244 used to read the deformation of the torsion springs 236 and 237. In addition, the one or more materials used for the mechanical structure of the first torsion spring 236 and the second torsion spring 237 include steel, aluminum alloy, and titanium alloy.

[0078] Drive unit 212 includes a frame 228 for rigidly supporting the components of drive unit 212. A first torsion spring 236 has a first flange 254 connected to gearbox 232 and a connecting flange 256 engaged with a second torsion spring 237. Second torsion spring 237 includes a second flange 256 connected to frame 228. The first and second torsion springs 236, 237 are axially connected, parallel to the second axis I2 of drive unit 112. Drive unit 212 also includes an encoder module 244 having an encoder ring 246 and a read head 248. Encoder module 244 directly registers the relative rotation of the second flange 256 of the second torsion spring 237 relative to the first flange 254 of the first torsion spring 236 about the second axis I2, without using frame 228 as an angular reference point. A brushless motor 230, enclosed by torsion springs 236, 237, is connected to gearbox 232. The gearbox 232 extends through the frame 228 to engage the load 250 , and the gearbox 232 includes an output shaft 234 that meshes with the load 250 . Figures 7A to 7C The illustrated load 250 is associated with the mechanical system or transmission unit 114 driven by the drive unit 212 . FIG. 7B to FIG. 7C The embodiment of the drive unit 212 in FIG. 2 reduces manufacturing costs by using two different torsion springs 236 , 237 .

[0079] Figures 8A to 8C Another embodiment of a drive unit 212 is shown. As shown, torsion springs 236 and 237 are integrated in series at the starting end of the drive unit 212, opposite the load 250, rather than being located between the gearbox 232 and the load 250. The first flange 254 of the first torsion spring 236 is connected to the gearbox 232. The second torsion spring 236 has a second flange 256 connected to the frame 228 of the drive unit 212. The first and second torsion springs 236 and 237 are oriented along the radial dimension of the drive unit 212 to interrupt the axial relative position chain of the various components. The first torsion spring 236 has a linear segment 243 extending parallel to the second axis I2. The second torsion spring 237 has a linear segment 245 extending parallel to the second axis I2 at a greater radial distance from the second axis I2 than the first torsion spring 236. The second torsion spring 237 also has at least two opposing arcuate segments 247 that extend partially and radially around the first torsion spring 236.

[0080] The first torsion spring 236 and the second torsion spring 237 are connected together by a fastener 241, which is radially oriented relative to the second axis I2 on the connecting flange 255. The first torsion spring 236 and the second torsion spring 237 form a unified elastic component 235. The equivalent stiffness value of the unified elastic component 235 is preferably between 100 Nm / rad and 5000 Nm / rad. This range of values allows for accurate and stable torque control of the drive unit 212. This makes it particularly convenient to Figures 8A to 8C The illustrated assembly of the drive unit 212 and the torsion springs 236, 237 is well defined and repeatable. In one exemplary embodiment, the stiffness of the elastic component 235 has a value of approximately 2000 Nm / rad.

[0081] Figure 8C The chain of mating parts between the torsion springs 236, 237 is highlighted, with the individual mating parts having specific dimensional tolerances, which allows clearance for the hole 257 in the second torsion spring 237 to receive a fastener 241 for connecting the first torsion spring 236 and the second torsion spring 237. The first torsion spring 236 circumferentially surrounds the motor 230 relative to the second axis I2 and includes a linear segment 243 extending parallel to the second axis I2. Figures 8A to 8C The embodiment of the drive device 212 in the embodiment further reduces weight and reduces occupied space by adopting a single frame 228. In addition, particularly for the first torsion spring 236, manufacturing costs are also reduced.

[0082] Figure 9A The overall structure of drive unit 312 is shown, which includes a first torsion spring 336 connected in series with a second torsion spring 337 and a third torsion spring 339 connected in parallel. It will be appreciated that drive units 212 and 312 are different embodiments of drive unit 112. Advantageously, first torsion spring 336 is connected in series with the second torsion spring 337 and the third torsion spring 339 connected in parallel and is located at the starting end of drive unit 312, opposite load 350, rather than between gearbox 332 and load 350. The dashed line connecting motor 330 and torsion springs 336, 337, 339 indicates that the interaction between these components is negligible because the interaction between motor 330 and torsion springs 336, 337, 339 is approximately two orders of magnitude smaller than the interaction between gearbox 332 and torsion springs 336, 337, 339.

[0083] Figures 9B to 9DAn embodiment of a drive unit 312 is shown. Drive unit 312 includes a first torsion spring 336, a second torsion spring 337, and a third torsion spring 339, wherein torsion springs 336, 337, and 339 form a unified elastic assembly 335. The equivalent stiffness of unified elastic assembly 335 is preferably between 100 Nm / rad and 5000 Nm / rad, a range that enables precise and stable torque control of drive unit 312. In an exemplary embodiment, the stiffness of elastic assembly 335 is approximately 2000 Nm / rad. The desired stiffness of elastic assembly 335 depends on various factors, such as the resolution of encoder module 344 used to read the deformation of torsion springs 336, 337. Furthermore, the one or more materials used in the mechanical structure of torsion springs 336, 337, and 339 include steel, aluminum alloy, and titanium alloy.

[0084] Drive unit 312 includes a frame 328 for rigidly supporting the components of drive unit 312. A first torsion spring 336 includes a first flange 354 connected to gearbox 332, and connecting flanges 355 and 359 connected to second and third torsion springs 337 and 339. Second torsion spring 337 includes a second flange 356 connected to frame 328 and engages with first torsion spring 336 at one or more connecting flanges 355. The first and second torsion springs 336 and 337 are connected together by fasteners 341, which are oriented radially relative to second axis I2 at one or more connecting flanges 355. The third torsion spring 339 includes a third flange 358 connected to frame 328 and engages with first torsion spring 336 at one or more connecting flanges 359. The first and third torsion springs 336 and 339 are connected together by fasteners 341, which are oriented radially relative to second axis I2 at one or more connecting flanges 359. The second torsion spring 337 and the third torsion spring 339 form at least two opposing arcuate segments 347 , 349 that partially and circumferentially extend around the first torsion spring 336 .

[0085] As shown, torsion springs 336, 337, and 339 are located at the starting end of drive unit 312, opposite load 350, and not between gearbox 332 and load 350. First torsion spring 336 has a linear section 343 extending parallel to second axis I2. Second torsion spring 337 has a linear section 345 extending parallel to second axis I2, with a radial distance from second axis I2 greater than the radial distance between first torsion spring 336 and second axis I2. Third torsion spring 339 also has a linear section 357 extending parallel to second axis I2, with a radial distance from second axis I2 greater than the radial distance between first torsion spring 336 and second axis I2.

[0086] Drive unit 312 also includes an encoder module 344 having an encoder ring 346 and a read head 348. Encoder module 344 can simultaneously read the deformation of flange 356 of second torsion spring 336 and flange 358 of third torsion spring 337, respectively. Flanges 356 and 358 are rigidly connected to frame 328. Brushless motor 330, surrounded by torsion springs 336, 337, and 339, is connected to gearbox 332. Gearbox 332 extends through frame 328 to engage load 350 and includes an output shaft 334 that meshes with load 350. Figures 9A to 9D The illustrated load 350 is associated with the mechanical system or transmission unit 114 driven by the drive unit 312 . Figures 9B to 9C The embodiment of the drive unit 312 in FIG. 3 reduces manufacturing costs by using two different torsion springs 336 and 337. In addition, Figures 9B to 9D The assembly of the drive unit 312 and the torsion springs 336 , 337 , 339 in the embodiment shown is well defined and repeatable.

[0087] FIG. 10A to FIG. 10B Another embodiment of the drive unit 312 is shown. Torsion springs 336, 337, and 339 are located at the starting end of the drive unit 312, opposite the load 350, rather than between the gearbox 332 and the load 350. Without significantly changing the stiffness value, the axial length of the inner or first torsion spring 336 is reduced by distributing the axial length of the inner or first torsion spring 336 so that the plurality of linear segments 343 of the first torsion spring 336 do not extend beyond the motor 330 along the second axis I2. This embodiment of the drive unit 312 preserves the original length of the deformable portion of the torsion spring 336 and reduces the overall axial footprint.

[0088] Figure 11A and Figure 11B Another embodiment of a drive unit 360 is shown. Drive unit 360 includes a frame 362, a motor 364, a gearbox 366, a torsion spring 368, and a rotary encoder 369, which includes an encoder ring 370 and a read head 372. Assume that a load 374 is connected to drive unit 360. According to this embodiment, rotary encoder 369 is located on the back or rear side of the assembly, and gearbox 366 is simplified and has a single torsion spring.

[0089] Due to the arrangement of the torsion spring 368, the base and deformable portion of the spring are flipped 180° relative to the plane of the frame 362. The rotary encoder module 369 is located on the rear side of the assembly, using the base of the spring 368 as a mounting surface. FIG. 10A to FIG. 10BCompared to the arrangement in the embodiment of FIG. 1 , this arrangement improves the assembly and disassembly process of the rotary encoder module; in particular, it simplifies the installation procedure for ensuring the required axial distance between the encoder ring and the encoder read head.

[0090] like FIG. 12A to FIG. 12B As shown, Figure 12A shown FIG. 11A to FIG. 11B The gearbox of the embodiment is arranged relative to Figure 12B shown FIG. 10A to FIG. 10B The embodiment of has one less component. Specifically, Figure 12B The part marked as 367 is Figure 12A This is probably because (i) the rotary encoder module is mounted on the back of the assembly, and (ii) the circular spline 376 of the harmonic drive (HD) is mounted on the spring (i.e. Figure 12A 368 of them; Figure 12B 368, 373) instead of on component 367. As a result, the assembly and disassembly process of the SEA is improved and the manufacturing cost is reduced.

[0091] like Figure 12A As shown, Figure 12B Compared with the two springs 368 and 373 shown in FIG, one spring 368 is missing, that is, Figure 12A There is no spring 373. This can be achieved by redesigning the spring 368, specifically by increasing the axial distance between the spring connection flange 371 and the main plane of the frame 362 (see distance 378). This adjustment allows the frame 362 and the spring 368 to be directly connected and Figure 12B This design has the least impact on its stiffness compared to other designs.

[0092] Figure 9A The spring diagram in the figure is applicable to FIG. 11A to FIG. 12A Example of .

[0093] By following 11A to 12A The above description of the embodiments shown is based on the needs of APO. All the design schemes adopted in the components introduced in this section can meet the following requirements of APO and its drive unit (especially the elastic element therein): (i) the stiffness value of the spring is within a certain numerical range to enable accurate and stable torque control of the system; (ii) the elastic element is designed based on the fatigue criterion; (iii) the assembly process of SEA and the elastic element therein is clearly defined; (iv) the weight and radial and axial space occupied by SEA and the elastic element therein are limited; (v) for large-scale production, the manufacturing cost of the elastic element is low.

[0094] Figure 13A and Figure 13B Another embodiment of a drive unit 380 is shown. The drive unit 380 includes a frame 382, a motor 384, a gearbox 386, two torsion springs 388 and 389, and a rotary encoder 390 including an encoder ring 391 and a reading head 393. Assume that a load 392 is connected to the drive unit 380.

[0095] The provision of drive unit 380 reduces weight and costs. Therefore, only a small section of encoder ring is required to read the torsional deformation of the spring. To reduce the manufacturing cost of frame 382, a second torsion spring 389 is provided to connect frame 382 and first torsion spring 388, thereby compensating for their relative positions in both radial and axial directions. Thus, second torsion spring 389 helps reduce the required tolerances for assembly of frame 382 and first torsion spring 388.

[0096] Figure 9A The spring diagram in the figure is applicable to FIG. 13A to FIG. 13B In addition, the above-mentioned embodiment can also be satisfied. Figures 11A-11B The same design criteria as the embodiments.

[0097] Figure 14 Another embodiment of an elastic element 400 is shown. The elastic element includes multiple deformable components, including a first series-parallel elastic body 402, a second series-parallel elastic body 404, and a series elastic body 406. The line connecting the motor 408 and the series elastic body 406 is a dashed line because, in the design of the drive unit, the interaction between them can be assumed to be two orders of magnitude smaller than the interaction between the gear train 410 and the series elastic body 406, which in turn is transmitted to the load 412.

[0098] Furthermore, features and / or components of one embodiment, example, or figure described, shown, or referred to herein may be combined with features and / or components of other embodiments, examples, or figures described, shown, or referred to herein to provide embodiments, examples, or implementation variations that are not explicitly described verbally or visually shown herein.

[0099] It will be appreciated by those skilled in the art that the elastic element assembly may include multiple deformable components connected in parallel or in series to develop further embodiments. These and other alternatives will readily occur to those skilled in the art based on the disclosure herein and are encompassed by the subject matter of the present invention.

[0100] It should be understood that even though many features and advantages of various embodiments of the present invention, as well as details of the structure and function of various embodiments, have been set forth in the foregoing description, such detailed description is only illustrative and that within the scope of the principles of the invention, changes may be made to the details (especially the structure and arrangement of parts) within the full scope of the broad general meaning of the terms expressed in the appended claims.

Claims

1. A driving device (112) comprising: Gearbox based on harmonic drive (132); a motor (130) for transmitting rotation and torque to an output shaft (134) through a gearbox (132) for supporting a mechanical load (150); and A first torsion spring (136) connects the motor (130) and the gearbox (132) to the frame (128).

2. The drive device (112) according to claim 1, characterized in that The first torsion spring (136), the motor (130) and the gearbox (132) are aligned along the rotation output axis (I2), the first torsion spring (136) and the mechanical load (150) are located at opposite ends of the drive device (112), and the motor (130) and the gearbox (132) are located between the first torsion spring (136) and the mechanical load (150).

3. The drive device (112) according to claim 2, characterized in that An encoder module (144) is also included.

4. The drive device (112) according to claim 3, characterized in that The encoder module (144) is capable of directly reading the relative rotation (Δθ) of the output flange (156) of the first torsion spring (136) around the rotational output axis (I2).

5. The driving device (112) according to claim 1, characterized in that The interaction between the motor (130) and the first torsion spring (136) is two orders of magnitude smaller than the interaction between the gear box (132) and the first torsion spring (136).

6. A driving device (212) comprising: Gearbox based on harmonic drive (232); a motor (230) for transmitting rotation and torque through a gearbox (232) for supporting a mechanical load (250); a first torsion spring (236) and a second torsion spring (237) connected in series, the first torsion spring (236) and the second torsion spring (237) being used to connect the motor (230) and the gearbox (232) to the frame (228); and Encoder module (244).

7. The driving device (212) according to claim 6, characterized in that The second torsion spring (237) has at least two opposing arcuate segments (247) that partially and circumferentially extend relative to the first torsion spring (236).

8. The driving device (212) according to claim 6, characterized in that The first torsion spring (236), the second torsion spring (237), the motor (230) and the gearbox (232) are aligned along a rotational output axis (I2).

9. The driving device (212) according to claim 6, characterized in that The first torsion spring (236) and the second torsion spring (237) and the mechanical load (250) are located at opposite ends of the driving device (212), and the motor (230) and the gear box (232) are located between the first torsion spring (236) and the mechanical load (250).

10. The driving device (212) according to claim 6, characterized in that The first torsion spring (236) and the second torsion spring (237) are connected together by a fastener (241) oriented along the axial direction of the drive device (212).

11. The driving device (212) according to claim 6, characterized in that The first torsion spring (236) has a linear section (243) extending parallel to the rotation output axis (I2).

12. The driving device (212) according to claim 6, characterized in that The second torsion spring (237) has a linear section (245) extending parallel to the rotation output axis (I2).

13. The driving device (212) according to claim 6, characterized in that The radial distance between the second torsion spring (237) and the rotation output axis (I2) is greater than the radial distance between the first torsion spring (236) and the rotation output axis (I2).

14. The driving device (212) according to claim 6, characterized in that The first torsion spring (236) and the second torsion spring (237) are connected together by a fastener (241) oriented along the radial direction of the drive device (212).

15. A driving device (312) comprising: Gearbox based on harmonic drive (332); a motor (330) for transmitting rotation and torque through a gearbox (332) for supporting a mechanical load (350); as well as A first torsion spring (336) is connected in series with a second torsion spring (337) and a third torsion spring (339) connected in parallel, the first torsion spring (336) is connected in series with the motor (330) and the gear box (332) and is connected to the frame (328).

16. The driving device (312) according to claim 15, characterized in that Also included is an encoder module (344).

17. The driving device (312) according to claim 15, characterized in that The first torsion spring (336), the second torsion spring (337), and the third torsion spring (339) and the mechanical load (350) are located at opposite ends of the driving device (312), and the motor (330) and the gear box (332) are located between the first torsion spring (336), the second torsion spring (337), and the third torsion spring (339) and the mechanical load (350).

18. The driving device (312) according to claim 15, characterized in that The second torsion spring (337) and the third torsion spring (339) form at least two opposing arcuate segments (347, 349) that partially and circumferentially extend relative to the first torsion spring (336).

19. The driving device (312) according to claim 15, characterized in that The first torsion spring (336) and the second torsion spring (337) are connected together by a fastener (341) oriented along the radial direction of the drive device (312).

20. The driving device (312) according to claim 15, characterized in that The first torsion spring (336) includes a linear segment (343) extending around the gearbox (332) parallel to the rotational output axis (I2), and the motor (330) extends parallel to the rotational output axis (I2) away from the mechanical load (350) and beyond the linear segment (343) of the first torsion spring (336).

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