Torque sensor element and torque sensor

Abstract

A torque sensor element for measuring torque applied to a joint is described. The torque sensor element includes an outer frame and an inner frame connected to first and second sides of the joint, respectively, and a compliant arrangement connecting the outer frame to the inner frame. The compliant arrangement includes first and second members each extending between and connecting the outer frame and the inner frame, and each being resilient and deformable to allow some relative rotation between the outer frame and the inner frame in response to the applied torque. A connecting structure extends between the first and second members and includes a first portion located between the first and second members, the first portion being configured to move an amount determined by the extent of relative rotation between the outer frame and the inner frame caused by the torque applied to the joint in response to deformation of the first and / or second members.

Description

Technical Field

[0001] This invention relates to a torque sensor element for measuring torque in a joint. The invention also relates to a torque sensor including a torque sensor element, particularly, but not exclusively, for measuring torque in the joints of a robotic device. Background Technology

[0002] Some types of robots have one or more articulated arms with end effectors, also known as manipulators, used to perform certain tasks. A robot typically consists of a body and multiple mechanical links connecting the end effector to the body. These mechanical links are usually connected to each other via one or more rotatable joints. Control of these rotatable joints allows control of the end effector's movement to perform a given task. For example, one or more joints can be operated by a motor that applies torque to control the joint's position. Various control schemes can be used to control the robot. For example, some control schemes may apply impedance control, which allows control of the end effector based on the relationship between the external force applied to it and the end effector's position.

[0003] Joint-related data is typically collected to allow for the control of robotic devices and, for example, to determine how the robot positions itself relative to its environment or how it interacts with it. For instance, knowing the orientation of a joint can be important for precisely controlling the position of an end effector or other parts of a robotic device. This joint-related data can be obtained using certain types of detectors or sensors. For example, detectors in the joints of a robotic device can collect data related to the joint's position (e.g., angular position) and feed that data back to the controller, allowing the controller to control the joint accordingly. Torque sensors can also be used to detect the torque applied to a joint. For example, a joint can be controlled by applying torque to it via a joint motor. Torque sensors can be used to measure the torque applied by the motor.

[0004] Detecting the torque applied to the joints can also allow for the detection of torques or forces exerted on the robot by its environment. For example, a torque sensor can detect external torques indicating a collision between the robot (e.g., an end effector) and objects in the environment. Quickly and accurately detecting such torques can be important for ensuring the safe operation of the robot. This is especially true when the robot operates in human environments, as it may have large moving masses that could pose a danger to humans if not safely controlled. A torque sensor can also, for example, allow determining the weight of a load carried by the robot by determining the external torque acting on it when the load is borne. Furthermore, since the joints of a robotic device can be controlled by applying torque to the joints, for example, via motors, measurements of the torques applied to control the joints can be made and these measurements taken into account in the calculations involved in controlling the joints.

[0005] Figure 1 A plan view of an exemplary prior art torque sensor element 100 for use in a joint of a robotic device (not shown) is shown. The prior art torque sensor 100 is generally planar and includes a circular frame comprising an outer frame 110, an inner frame 120, and an arrangement of beams 130 connecting the outer frame 110 to the inner frame 120. The torque sensor 100 includes a compliant arrangement consisting of a plurality of flexures 140 extending between and connecting the inner frame 120 and the outer frame 110. The inner frame 120 of the torque sensor 100 defines a central aperture 150 through which wires, etc., of the joint can pass when the torque sensor 100 is mounted in a joint of the robotic device. The torque sensor element 100 is generally circular and generally planar, and therefore can be located in a joint between a first and second component of the robotic device, such as a rotating “elbow” joint. The outer frame 110 includes a first series of holes 112 to allow the outer frame 110 to be secured to a first side of the joint of the robotic device, while the inner frame 120 includes a second series of holes 122 to allow the inner frame 120 to be secured to a second side of the joint. Therefore, when mounted in the joint, the first and second sides of the joint are connected to each other via a torque sensor 100, such that any torque applied around the joint is transmitted through the torque sensor 100.

[0006] Beam 130 is configured to connect the outer frame 110 and the inner frame 120 with relatively high stiffness, allowing the torque sensor 100 to transmit torque without significant movement between the outer frame 110 and the inner frame 120. However, beam 130 allows for a small amount of relative rotational movement between the outer frame 110 and the inner frame 120 under applied torque. When this relative rotational movement occurs, the flexural portion 140 deforms. The degree of deformation of the flexural portion 140 can be measured to measure the torque applied to the torque sensor 100.

[0007] Each flexure 140 is arranged opposite to another flexure 140 as a pair of flexures. At the free end of each flexure 140 is an electrode plate, which, together with the electrode plate of the other flexure in the pair, forms a corresponding capacitive sensor C1, C2, C3, C4 for each pair of flexures 140. When no torque is applied to the torque sensor 100, the electrode plates of the inner flexures 140 in this pair are arranged substantially parallel to each other. One pair of electrode plates in each capacitive sensor C1, C2, C3, C4 is configured to move relative to each other as the flexure 140 deforms, increasing or decreasing the gap between them. The capacitance of capacitive sensors C1 to C4 varies according to the corresponding distance between each pair of electrodes (i.e., the size of the gap) and also varies with the degree of overlap between the electrodes. Therefore, when the flexure 140 flexes due to the relative movement of the outer frame 110 and the inner frame 120, the capacitive sensor 142 detects the change in capacitance. This change in capacitance can be detected and used to determine the torque applied to the torque sensor 100.

[0008] Figure 1 The arrows illustrate how the rotational direction between the inner frame 120 and the outer frame 110 causes the corresponding electrode plates of the capacitive sensors C1, C2, C3, and C4 to move. Specifically, when the outer frame 110 is held in a fixed position, the applied torque causing the inner frame 120 to rotate clockwise forces the electrodes of the first and third capacitive sensors C1 and C3 to separate. Simultaneously, under the same torque, the electrodes of the second and fourth capacitive sensors C2 and C4 are forced closer together. The applied torque can be determined by measuring the resulting capacitance change. Summary of the Invention

[0009] According to a first aspect of the invention, a torque sensor element for measuring torque applied to a joint is provided, the torque sensor element comprising: an outer frame connected to a first side of the joint; an inner frame connected to a second side of the joint; and a compliant means for connecting the outer frame to the inner frame, wherein the compliant means comprises: a first member and a second member, each member extending between the outer frame and the inner frame and connecting the outer frame to the inner frame, and each member being elastic and deformable to allow at least some relative rotation between the outer frame and the inner frame in response to torque applied to the joint; and a connection structure extending between the first member and the second member, the connection structure including a first portion located between the first member and the second member, the first portion being configured to move by an amount determined by the degree of relative rotation between the outer frame and the inner frame caused by torque applied to the joint in response to deformation of the first member and / or the second member.

[0010] An example according to the invention allows the torque applied to the torque sensor element to cause movement of a first portion of the connecting structure. This allows for a reliable way of translating the relative rotation of the outer and inner frames into measurable movement of a portion of the torque sensor element. In an example according to the invention, it is not necessary to measure the overlap between portions of the compliant structure, such as... Figure 1 The situation in the prior art apparatus is illustrated. Therefore, an alternative to such a prior art apparatus can be provided according to the examples according to the present invention.

[0011] The movement of the first part of the connecting structure in response to deformation of the first and / or second member may include at least a rotational component.

[0012] This allows the relative rotation between the inner and outer frames to be measured by measuring the rotation of a first portion on the connecting structure. The rotation of the first portion can, for example, be about a point on the connecting structure. For instance, the first portion can be substantially circular and can be configured to rotate about a center.

[0013] The torque sensor element may include a first arm connected to the first part, wherein the first arm is configured to move by an amount determined by the degree of relative rotation between the outer frame and the inner frame caused by the torque applied to the joint.

[0014] The first arm can convert the motion of the first part into a larger motion of the arm. For example, the rotational motion of the first part can be converted into a larger motion of the free end of the arm. The free end of the arm can move away from the first part.

[0015] The first arm may extend in a direction away from the inner frame. The outer frame may include gaps. The first arm may extend through these gaps.

[0016] By extending away from the inner frame, the first arm can be allowed to extend further from the first portion. This allows the first arm to amplify the movement of the first portion to a greater extent. For example, the first arm can convert a relatively small rotational motion of the first portion into a large translational motion of the free end of the first arm. If the outer frame includes a gap, the first arm can extend through the gap. This provides a convenient way to make the first arm longer and amplify the rotational motion of the first portion to a greater extent. In some examples, the gap in the outer frame is completely broken, such that the outer frame is divided into separate sections. In other examples, the gap in the outer frame may include a thinner portion of the outer frame. In such examples, the first arm can extend above or below the thinner portion of the outer frame forming the gap. The first arm can be arranged, for example, to include complementary thinner portions to allow the first arm to pass above or below the thinner portion of the outer frame.

[0017] The connection structure may include at least one linking element that connects a first member or a second member to a first part and is configured to facilitate movement of the first part when torque is applied to the joint.

[0018] The connection structure may include a first linking element configured to connect a first member to a first portion and a second linking element configured to connect a second member to the first portion. The first and second linking elements may be configured to facilitate movement of the first portion when torque is applied to the joint.

[0019] When the compliant structure deforms due to the applied torque, the linking element can facilitate the movement of the first part.

[0020] One or more beam elements can connect the outer frame to the inner frame. Each of the one or more beam elements may include one or more connecting members that connect the outer frame to the inner frame.

[0021] One or more beam elements provide rigidity in the connection between the outer and inner frames. These beam elements can be configured to distribute stress across the entire torque sensor element. This allows the torque sensor element to limit the maximum stress at any point within the element to an acceptable level. For example, each of the beam elements may include one or more members that are bent or otherwise shaped to effectively distribute stress. In some examples, two beam elements may be provided. In other examples, three beam elements are provided. In still other examples, more than three beam elements may be provided.

[0022] The torque sensor element may include a third member and a fourth member, each extending between an outer frame and an inner frame and connecting the outer frame to the inner frame, and each of the third and fourth members is elastic and deformable to allow at least some relative rotation between the outer frame and the inner frame in response to torque applied to the joint; and a second connection structure extending between the third and fourth members, the connection structure including a second portion located between the third and fourth members, the second portion being configured to move by an amount determined by the degree of relative rotation between the outer frame and the inner frame caused by torque applied to the joint in response to deformation of the third and / or fourth members.

[0023] Providing a second connecting structure and a second portion thereon provides another portion whose movement indicates the torque applied to the joint. For example, in addition to the movement of the first portion, the applied torque can be measured using a measurement of the movement of the second portion. Some examples may allow for the measurement of the movements of both the first and second portions, used together to measure the applied torque. This can allow for the elimination of any asymmetry in the movement of the first and second portions under different torque directions. Furthermore, by providing additional measurement points, the ratio of measurement error to the measured value can be reduced.

[0024] The second part of the connecting structure may include a second arm configured to move by an amount determined by the degree of relative rotation between the outer and inner frames caused by the torque applied to the joint.

[0025] The second arm can convert the movement of the second part into a larger movement of the second arm in a manner similar to that described for the first arm. The second part can also extend away from the inner frame. The outer frame may include another gap. This gap can be configured to allow the second arm to extend through the gap. One or more linking elements can connect the second part to the third and fourth members, respectively, in the same manner as described for the first part.

[0026] According to a second aspect of the invention, a torque sensor is provided for measuring torque applied to a joint, the torque sensor comprising: a torque sensor element according to a first aspect of the invention; and a measuring element for measuring the amount by which a first portion of the torque sensor element moves in response to relative rotation between an outer frame and an inner frame caused by torque applied to the joint, thereby measuring the torque applied to the joint.

[0027] The measuring element can be configured to measure the rotation of the first part, thereby measuring the torque applied to the joint.

[0028] The measuring element may include a magnetic measuring element configured to measure the movement of the first part by measuring the change in the magnetic field caused by the movement of the first part of the connecting structure.

[0029] In the example where the torque sensor element includes a second portion, the torque sensor may include another measuring element for measuring the amount of movement of the second portion of the torque sensor element in response to the relative rotation between the outer and inner frames caused by a torque applied to the joint. The measuring element for measuring the movement of the second portion may have any of the characteristics described for the measuring element for measuring the movement of the first portion.

[0030] According to a third aspect of the invention, a robotic device is provided, comprising: a body; an end effector coupled to the body via one or more joints; a propulsion system for driving the one or more joints to control the state of the robotic device; and a torque sensor according to a second aspect of the invention, the torque sensor being arranged to measure torque applied to one of the one or more joints.

[0031] Further features and advantages of the invention will become apparent from the following description of preferred embodiments of the invention with reference to the accompanying drawings, which are given by way of example only. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of an exemplary prior art torque sensor element;

[0033] Figure 2 This is a schematic diagram of an example torque sensor element according to one aspect of the present invention;

[0034] Figure 3 This is a schematic diagram of another example torque sensor element according to one aspect of the present invention;

[0035] Figure 4 This is a schematic diagram of another example torque sensor element according to one aspect of the present invention;

[0036] Figure 5 This is a schematic diagram of an exemplary measuring element used in a torque sensor according to one aspect of the present invention;

[0037] Figure 6A An exploded perspective view of an example joint including a torque sensor element according to one aspect of the invention is shown.

[0038] Figure 6B It is also shown in decomposed form. Figure 6A The example shown is a side view of a joint.

[0039] Figure 6C It shows Figure 6A and 6B A perspective view of the compact form of the example joint shown;

[0040] Figure 6D It shows Figures 6A to 6C A side view of the compact form of the example joint shown; and

[0041] Figure 7 A simplified schematic diagram of an example robotic device including an example torque sensor according to one aspect of the present invention is shown. Detailed Implementation

[0042] Examples of the present invention relate to torque sensor elements for use as torque sensors in robotic devices. Such robotic devices can be configured to interact with humans in human environments. However, examples of the present invention can find applications in other fields, such as commercial robots designed to operate in non-human environments (e.g., factory environments). Some examples of the present invention are configured to be located in the joints of a robotic device and used to determine the torque applied to or exerted by the joints of the robotic device. However, example torque sensors according to the present invention can be applied to detect torque in other parts of a robotic device, for example, detecting torque between components of the robotic device that are configured to remain substantially stationary relative to each other during operation of the robotic device. Example torque sensors according to the present invention can also be applied to torque measurement applications outside the field of robotics. Torque sensor elements will now be described by way of example.

[0043] Figure 2 A plan view of an example of a first torque sensor element 1000 according to the present invention is shown. The first torque sensor element 1000 is used in robotic devices ( Figure 2 The torque sensor in the joint (not shown). The torque sensor 1000 in this example is shared. Figure 1 This describes certain features of a prior art torque sensor 1000. The torque sensor 1000 includes a generally annular outer frame 1010, a generally annular inner frame 1020, and means of beams connecting the outer frame 1010 to the inner frame 1020. In this example, a first beam assembly 1030a and a second beam assembly 1030b connect the outer frame 1010 to the inner frame 1020. The torque sensor element 1000 is generally circular and generally planar. The first and second beam assemblies 1030a and 1030b are arranged on opposite sides of the torque sensor element 1000 and serve to provide a degree of rigidity between the outer frame 1010 and the inner frame 1020 while allowing only a small amount of rotational movement between them. In some examples, the torque sensor element 1000 may be made of a metal such as steel. For example, the torque sensor element 1000 may be made of spring steel, such as monolithic spring steel.

[0044] The torque sensor 100 has a central aperture 1050 to allow wires, etc., to pass through it. The outer frame 1010 also includes a first series of holes 1012 to allow the outer frame 1010 to be secured to a first side of the joint of the robotic device, while the inner frame 1020 includes a second series of holes 1022 to allow the inner frame 1020 to be secured to a second side of the joint of the robotic device. When mounted in the joint, the first and second sides of the joint are connected to each other via the torque sensor 1000, and any torque applied to the joint is transmitted through the torque sensor 1000.

[0045] Similar to the prior art torque sensor 1000, the torque sensor 1000 includes a compliance device connecting the outer frame 1010 to the inner frame 1020. This compliance device will be described in more detail below.

[0046] Beams 1030a-c connect the outer frame 1010 and the inner frame 1020 with relatively high stiffness, sufficient to allow a small amount of rotational movement between the outer frame 1010 and the inner frame 1020 given a suitable lever with a given applied torque. When such rotational movement occurs, the deformation of the compliant device is related to the degree of rotation between the outer frame 1010 and the inner frame 1020, which itself is determined by the applied torque.

[0047] The compliant device in this example includes a first portion 1040a, which includes a first member 1042a and a second member 1044a, each extending between an outer frame 1010 and an inner frame 1020 and connecting the outer frame 1010 and the inner frame 1020. When a torque is applied between the outer frame 1010 and the inner frame 1020, the first member 1042a and the second member 1044a each respond to at least some of the relative rotation between the outer frame 1010 and the inner frame 1020 and become elastic and deformable.

[0048] The first component 1042a is connected to the second component 1044a via a first connecting structure 1060a. The first connecting structure 1060a includes a first portion 1062a located between the first component 1042a and the second component 1044a. The first portion 1062a is configured to move when the first component 1042a and / or the second component 1044a deform due to relative rotation between the outer frame 1010 and the inner frame 1020.

[0049] In this example, the motion of the first portion 1062a is a rotational motion when there is relative rotation between the outer frame 1010 and the inner frame 1020. The rotational motion of the first portion 1062a is a result of the first portion 1062a being part of a connecting structure 1060a that connects the first member 1042a to the second member 1044a. Therefore, the relative rotation between the outer frame 1010 and the inner frame 1020 can be measured by measuring the rotation of the first portion 1062a. In this example, the first portion 1062a is generally circular and configured to rotate about its center when a torque is applied. In other examples, the motion of the first portion 1062a of the connecting structure may be a translational motion, or the motion may include a translational component in addition to a rotational component. The overall structure of the connecting structure can determine the type of motion achieved by the first portion 1062a when the first member 1042a and / or the second member 1044a deforms.

[0050] The first member 1042a 1044a is divided into two arms 1043a extending between the first and second members 1042a, for connection to one side of the connecting structure 1060a. The second member 1044a is similarly divided into two arms (in... Figure 2 (Not marked) to connect to opposite sides of the connecting structure 1060a. In addition to the first portion 1062a, the connecting structure 1060a also includes a first linking element 1046a and a second linking element 1048a. The first member 1042a and the second member 1044a are connected to the respective sides of the first portion 1062a via the first and second linking elements 1046a and 1048a. The linking elements 1046a and 1048a are configured to allow the first compliant portion 1040a to deform due to relative rotation between the outer frame 1010 and the inner frame 1020, thereby causing rotation of the first portion 1062a. In this example, the linking elements 1046a and 1048a are shaped as arcuate elements oriented in opposite directions (radially inward and radially outward, respectively) to facilitate rotation of the first portion 1062a. In other examples, the connection structure 1060a may include any suitable means for linking the first member 1042a to the second member 1044a and causing movement of the first portion 1062a when relative rotation occurs between the outer frame 1010 and the inner frame 1020. The manner in which the first portion 1062a is connected between the first member 1042a and the second member 1044a can affect the manner in which the first portion 1062a moves in response to relative rotation of the outer frame 1010 and the inner frame 1020.

[0051] The compliant device connecting the outer frame 1010 to the inner frame 1020 also includes a second compliant portion 1040b having features similar to the first compliant portion 1040a. The second compliant portion 1040b includes a third member 1042b and a fourth member 1044b, and a connecting structure 1060b connects the third member 1042b to the fourth member 1044b. The connecting structure includes a second portion 1060b configured in the same manner as the first portion 1062a described above, such that when a torque applied to the torque sensor element 1000 causes relative rotation between the outer frame 1010 and the inner frame 1020, the second portion 1062b moves in a manner similar to the first portion 1062a. The features of the second portion 1040b correspond to and operate in the same manner as described above with respect to the first portion 1040a, and a description of this operation will not be repeated.

[0052] Torque sensor element 1000 is configured such that, Figure 2 As shown, if the outer frame 1010 remains fixed and the applied torque causes the inner frame 1020 to rotate clockwise, then the first part 1062a rotates clockwise about its own axis. Similarly, for the same relative rotation between the outer frame 1010 and the inner frame 1020, the second part 1062b also rotates clockwise about its own axis. The directions of these rotations are as follows: Figure 2 As indicated by the arrows in the diagram. If the torque causes relative rotation between the outer frame 1010 and the inner frame 1020 in the opposite direction to the aforementioned direction, then the first and second parts 1060a and 1060b rotate counterclockwise relative to their own axes.

[0053] To measure the torque applied to a joint in which a torque sensor element 1000 is mounted, a measuring element (not shown) is used to measure the degree of movement of one or both of the first part 1062a and the second part 1062b, in this example, the degree of rotation. For example, to measure the degree of rotation of the second part 1062b, the measuring element can be used to measure the movement of point 1063b on the second part 1062b. In some examples, a magnetic measuring element is used to measure the movement of the second part 1062b. In one such example, a diameter-magnetized magnet ( Figure 2 (Not shown in the image), i.e., having north and south poles on a single surface rather than on opposing surfaces, is attached to the first part 1062a. In this example, a rotational position sensor (not shown) is then positioned to measure the rotation of a radially magnetized magnet. The rotational position sensor may include an array of Hall sensors, for example, an array of five Hall sensors. Each Hall sensor is configured to sense the magnetic field of the radially magnetized magnet and the orientation of the magnet, so that the rotation of the first part 1062a can be determined from the magnetic field measurements obtained from the Hall sensors.

[0054] The aforementioned compliant mechanism of the torque sensor element 1000 allows for a small degree of rotation between the outer frame 1010 and the inner frame 1020, resulting in movement of the first portion 1062a and the second portion 1062b. This movement can be measured to determine the torque applied to the torque sensor element. Specifically, the first portion 1062a and the second portion 1062b are located on the connection structure 1060a, 1060b between the respective pairs of deformable members, resulting in rotational movement of the first portion 1062a and the second portion 1062b. This can be combined with... Figure 1 In contrast to existing technology devices, Figure 1 Existing technical devices rely on measuring the spacing or overlap between adjacent flexural portions 140. Providing a connecting portion between the first member 1042a and the second member 1044a provides this movement of the first portion 1062a, which provides a reliable way to convert the relative rotation of the outer and inner frames 1010, 1020 into measurable, for example, rotational motion.

[0055] In this example, beam assemblies 1030a and 1030b are configured to maintain a suitable degree of rigidity to allow the torque sensor element 1000 to effectively transmit torque without significant movement between the outer frame 1010 and the inner frame 1020. Simultaneously, small rotational movements between the outer frame 1010 and the inner frame 1020 are converted into measurable rotational movements of the first portion 1062a and the second portion 1062b, which, in this example, rotate about their own axes. The connection structure can also help increase the rigidity of the connection between the outer frame 1010 and the inner frame 1020 while providing this measurable rotational movement.

[0056] In some examples, an amplifying device is provided to amplify the movement of one or both of the first and second connecting structures. The amplifying device may, for example, include a protrusion or extension, such as an arm, extending from a given one of the first and second parts. Such a protrusion or extension can be configured to amplify the movement of the given one of the first and second parts to which it is connected. Thus, for example, for a given degree of movement of the first part, a protrusion connected to the first part can be configured to move to a greater degree. A similar protrusion connected to the second part can be configured to amplify the movement of the second part in a similar manner.

[0057] Figure 3 An exemplary torque sensor element 1000' is shown, which is Figure 2A variant of the first torque sensor element 1000. The torque sensor element 1000' has the features of the first torque sensor element 1000 and additionally includes an arm 1064b' extending from the second portion 1062b'. The arm 1064b' extends from the second portion 1062b' and terminates at a free end 1063b'. Movement of the arm, such as movement of the free end 1063b', can be measured to determine the applied torque. Figure 3 The arrows indicate the direction of rotation of the second part 1062b' and the movement of the free end 1063b', for example, where the inner frame 1020' rotates clockwise relative to the outer frame 1010'. The arm 1064b' is configured to provide displacement of the free end 1063b' greater than a point on the second part 1062b' (e.g., ...). Figure 2 The displacement of point 1063b) of the torque sensor element 1000 with respect to a given degree of rotation of the second part 1062b'. Therefore, the movement of the free end 1063b' is an amplification of the movement of the second part 1062b', which is provided by the arm 1064b'. This allows a small degree of relative rotational motion between the outer frame 1010' and the inner frame 1020' to be converted into a relatively large displacement of the free end 1063b'. Figure 3 The arrows in the diagram illustrate the rotation of the second part 1062b' and the movement of the free end 1063b'. Therefore, a more sensitive torque sensor can be provided while maintaining the same level of rigidity. Similarly, rigidity can be increased while maintaining the same level of sensitivity.

[0058] although Figure 3 The example only includes one arm 1064b' connected to the second part 1062b, but in other examples, a similar arm may be provided on the first part 1062b' to amplify the movement of the first part 1062b. In the example, one or both of the first part 1062b' and the second part 1062b' may have such an arm attached thereto.

[0059] Figure 4 A second torque sensor element 2000 according to an example of the present invention is shown. The second torque sensor element 2000 shares many features with the first torque sensor element 1000, and these features are indicated by similar reference numerals.

[0060] The second torque sensor element 2000 includes an outer frame 2010, which comprises two separate portions: a first outer frame portion 2010a and a second outer frame portion 2010b. Therefore, the outer frame 2010 is discontinuous and does not form a complete loop around the inner frame 2020, but rather defines two discontinuous portions or "gaps," including a first gap 2010c and a second gap 2010d located on opposite sides of the outer frame 2010. The first outer frame portion 2010a and the second outer frame portion 2010b are configured to be rigidly attached to a joint. Figure 4 The two outer frames (not shown) are positioned on the same side of each other to maintain a fixed position relative to each other. In this example, the width of the first outer frame portion 2010a is generally greater than the width of the second outer frame portion 2010b. The outer frame 2010 includes a first series of holes 2012 for securing the outer frame 2010 to a first side of the joint, while the inner frame 2020 includes a second series of holes 2022 for securing the inner frame 2020 to a second side of the joint.

[0061] The outer frame 2010 is connected to the inner frame 2020 via multiple beam assemblies 2030a, 2030b, and 2030c. The beam assemblies 2030a-c are configured to distribute the stress caused by the applied torque throughout the torque sensor element 2000. This allows the maximum stress experienced by any single part of the torque sensor element 2000 to be limited. For example, it has been found that in examples where the torque sensor element 2000 comprises spring steel, an applied torque of 1.6 Nm produces a maximum stress of 180 MPa in the torque sensor element 2000. Spring steel typically has a yield stress of approximately 1200 MPa, although this can vary depending on the composition of the spring steel. In any case, it can be seen that in such an arrangement, the maximum stress at this applied torque level is far below the typical yield stress of spring steel. The values ​​given in this example are for a 0.8 mm spring steel torque sensor element 2000. Therefore, even under high torque, the maximum stress remains well below the stress level that could cause permanent material damage to the torque sensor element 2000.

[0062] In the example, torque sensor element 2000 can be configured to deform by a given maximum amount when a given maximum torque is applied to it. For example, based on the intended application of torque sensor element 2000, torque sensor element 2000 can deform by a specific amount at a given torque. Different examples of torque sensor element 2000 manufactured for different applications and different corresponding maximum torques can be configured to exhibit the same maximum deformation at these different maximum torques. For example, an example of torque sensor element 2000 intended for mounting in a shoulder joint, where the maximum torque applied to torque sensor element 2000 will be large, can be configured to deform less at a given torque than an example of torque sensor element 2000 intended for mounting in a wrist joint, where the applied maximum torque will be smaller. The amount by which example torque sensor element 2000 deforms at a given torque can be configured such that it exhibits the same maximum deformation at the corresponding maximum torque expected to be applied to the given torque sensor element 2000. The thickness of torque sensor element 2000 can be selected to provide the desired deformation resistance at the applied torque. For example, when the torque sensor element 2000 is made of spring steel, in order to achieve the same maximum deformation under the maximum applied torque in each application, the torque sensor element 2000 may have a thickness of about 4 mm when used in the shoulder joint and about 0.5 mm when used in the wrist joint.

[0063] exist Figure 4 In the example, there are three beam assemblies 2030a-c equidistantly spaced around the inner frame 2020. In other examples, there may be a different number of beam assemblies, such as two or more than three beam assemblies. Figure 4 In the examples shown, each beam assembly 2030a-c includes a set of connecting members. For example, the first beam assembly 2030a includes a set of connecting members 2032a, each connecting member connecting the outer frame 2010 to the inner frame 2020. In this example, each of the connecting members 2032a in the first beam assembly 2030a and the other beam assemblies 2030b-c has a curved shape defining two convex angles. In this example, each of the beam assemblies 2030a-c includes four such connecting members. Other examples may have different numbers of connecting members in each beam assembly. Furthermore, in other examples, the connecting members may be differently shaped, for example, including different numbers of convex angles, such as one convex angle or more than two convex angles. In some examples, convex angles may not be present, for example, one or more connecting members may be substantially linear.

[0064] The second torque sensor element 2000 includes a compliant device comprising a first compliant portion 2040a located between the first beam assembly 2030a and the second beam assembly 2030b, and a second compliant portion 2040b located between the first beam assembly 2030a and the third beam assembly 2030c. Since the second torque sensor element 2000 includes three beam assemblies 2030a-c, a third compliant portion 2040c is located between the second beam assembly 2030b and the third beam assembly 2030c. The first compliant portion 2040a includes a first member 2042a and a second member 2044a connected by a first connecting structure 2060a. Similarly, the second compliant portion 2040b includes a third member 2042b and a fourth member 2044b connected by the second connecting structure 2060b. The third compliant portion 2040c includes a fifth member 2042c and a sixth member 2044c connected by the third connecting structure 2060c.

[0065] The first connecting structure 2060a includes a first portion 2062a located between the first member 2042a and the second member 2044a. Similarly, the second connecting structure 2060b includes a second portion 2062b located between the third member 2042b and the fourth member 2044b. The first connecting portion 2060a includes linking elements 2046a and 2048a for providing flexibility and elasticity within the connecting structure 2060a. This facilitates the conversion of deformation of the first member 2042a and the second member 2044a into movement of the first portion 2062a, in this example, rotation. The second connecting portion 2060b includes similar linking elements (not labeled for clarity) that function in the same manner to facilitate movement of the second portion 2062b. In this example, each of the linking elements 2046a and 2048a is shaped as a convex corner on either side of the first portion 2062a. The linking elements on either side of the second portion 2062b have similar shapes. Linking members of different shapes can enable different types of movement of the first and second parts 2046a and 2048a. For example, the linking member on either side of the first part 2062a can be shaped such that the first part influences translational movement in, for example, a generally circumferential direction.

[0066] and Figure 2 and Figure 3 Similar to the example, the first part 2062a and the second part 2062b are configured to move when there is relative rotation between the outer frame 2010 and the inner frame 2020 due to an applied torque. Measuring the degree of movement of the first part 2062a and the second part 2062b allows for the measurement of the applied torque. In this example, the movement of the first part 2060a and the second part 2060b includes at least a rotational component.

[0067] exist Figure 4In the example shown, the first arm 2064a is connected to the first portion 2062a. In this example, the first arm 2064a extends radially outward away from the first portion 2062a and away from the inner frame 2020. The first arm 2062a terminates at a free end 2066a. The first arm 2064a converts the rotational motion of the first portion 2062a into displacement of the free end 2066a. The displacement of the free end 2066a can then be measured to measure the applied torque. Figure 4 As shown, the first arm 2064a extends a considerable distance from the first portion 2062a, which amplifies the movement of the free end 2066a, which is a given rotation of the first portion 2062a to a similar degree. Figure 3 The torque sensor element 1000' of arm 1064b' is generated in the manner described.

[0068] In the example, the first arm 2064a can extend through a gap in the outer frame. This allows the first arm 2064a to extend further from the first section 2062a, thereby providing greater displacement of the free end 2066a at a given torque.

[0069] Figure 4 An example is shown where a first arm 2064a extends through a first gap 2010c in the outer frame. In this example, the first arm 2064a includes two substantially right-angle bends such that the first arm 2064a extends through the first gap 2010c. The first arm 2064a includes a further substantially right-angle bend and subsequently extends in a substantially circumferential direction such that the first arm 2064a terminates at a first free end 2066a, near the center of a second portion 2010b of the outer frame 2010.

[0070] The second connection structure 2060b includes a second portion 2062b and a second arm 2064b extending from the second portion 2062b. The second arm 2064b extends in a similar manner to that described above for the first arm 2064a and may have any of the features described for the first arm 2064a. The second connection structure also includes a linking element on either side of the second portion 2062b (for clarity, in...). Figure 4 (Not marked), it resembles the linking elements 2046a, 2048a on either side of the first part 2062a. The second arm 2064a extends through the second gap 2010d in the outer frame and terminates at the second free end 2066b. The second free end 2066b is located near the center of the second part 2010b of the outer frame. Figure 4 In the example shown, the free ends 2066a and 2066b are basically circular; however, in other examples they can be different shapes.

[0071] The third connecting structure 2060c of the third compliant portion 2040c includes a similar linking element between the fifth member 2042c and the sixth member 2044c. This linking element serves to increase the overall compliance of the compliant device, thereby facilitating the movement of the first arm 2064a and the second arm 2064b when torque causes relative rotation between the outer frame 2010 and the inner frame 2020. In this example, the linking element of the third connecting structure 2060c includes a convex angle similar to the linking elements 2046a and 2048a of the first connecting structure 2060a.

[0072] As described above, the first and second free ends 2066a, 2066b are configured to convert the relative rotation between the outer frame 2010 and the inner frame 2020 into displacement, which can be measured to measure the torque applied to the torque sensor element 2000. In this example, when torque is applied, the movement of the first and second free ends 2066a, 2066b is along... Figure 4 The basic linear motion of the corresponding axes indicated by the arrows located at the first free end 2066a and the second free end 2066b. From Figure 4 As can be seen, in this example, the axis along with the first and second free ends 2066a and 2066b is configured to move slightly off-center from the horizontal direction shown in the figure. Specifically, the first free end 2066a is configured to move substantially along a tangent to a circle centered on 2062a and passing through the center of the first free end 2066a. Similarly, the second free end 2066b is configured to move substantially along a tangent to a circle centered on 2062b and passing through the center of the second free end 2066b.

[0073] When the inner frame 2020 rotates clockwise relative to the outer frame 2010, the first portion 2062a and the second portion 2062b also rotate clockwise. As a result, when the inner frame 2020 rotates clockwise relative to the outer frame 2010, each of the free ends 2066a and 2066b moves from right to left along its respective axis. When the inner frame 2020 rotates counterclockwise relative to the outer frame 2010, the rotation directions of the first and second portions 2062a and 2062b are reversed, and the first and second free ends 2066a and 2066b move from left to right along their respective axes.

[0074] In the example, the measuring element can be placed on and / or adjacent to the free ends 2066a and 2066b and used to measure the motion of the free ends 2066a and 2066b.

[0075] Figure 5 A magnetic measuring element is shown for measuring the motion of the first free end 2066a of a torque sensor element 2000. Figure 5In the example shown, in order to measure the movement of the first free end 2066a, a diameter-magnetized magnet 2070a is attached to the first free end 2066a. Figure 5 (Not shown in the image). Magnet 2070a includes a north pole 2072a and a south pole 2074a. Magnetic sensor 2080a is placed near magnet 2070a. Magnetic sensor 2080a can be a Hall sensor. Magnetic sensor 2080a is held in a fixed position relative to outer frame 2010. Figure 5 (Not shown in the image). For example, a magnetic sensor 2080a can be fixed to an outer frame 2010. In one example, the magnetic sensor 2080a is positioned approximately 1 mm above the magnet 2070a. When the first free end 2066a and the magnet 2070a attached thereto move due to an applied torque, the magnetic sensor 2080a senses the change in the magnetic field caused by the movement of the magnet 2070a. Various electrical connections (not shown) can be provided to the magnetic sensor 2080a to allow it to measure the magnetic field of the magnet 2070a. A similar magnetic measuring device can be used to measure the movement of the second free end 2066b.

[0076] In other examples, any suitable type of measuring element can be used to measure the motion of the first and second free ends 2066a, 2066b. For example, a capacitive sensor or an optical sensor can be used.

[0077] The example of measuring the motion of the two free ends 2066a, 2066b to measure the applied torque allows for certain advantages, because the motion of each arm 2064a, 2064b may not be perfectly symmetrical for clockwise and counterclockwise torques. However, since the arms 2064a, 2064b always experience opposite displacements relative to the center of the torque sensor element 2000 under the applied torque (i.e., when the first arm 2064a swings outward, the second arm 2064b swings inward, and vice versa), any error caused by this asymmetry can be offset by measuring the motion of the two free ends 2066a, 2066b. Furthermore, by taking more measurement points, such as two measurement points instead of one, the ratio between the error (i.e., uncertainty) and the measured value is reduced.

[0078] This arrangement allows for a significant amplification of the movement of the free ends 2066a and 2066b of the arms 2064a and 2064b compared to the relative rotational movement between the outer frame 2010 and the inner frame 2020 that causes the movement of the arms 2064a and 2064b. For example, the discontinuity of the outer frame 2010 allows the arms 2062a and 2062b to extend radially outward through one of the gaps 2010c and 2010d in the outer frame 2010. This allows for longer arms that provide greater displacement of the free ends 2066a and 2066b of the arms for a given degree of relative rotation between the outer and inner frames 2010 and 2020.

[0079] For these reasons, the movement of arms 2064a and 2064b is highly sensitive to applied torque. Furthermore, the discontinuous nature of the outer frame 2010 allows arms 2064a and 2064b to extend in such a way that their free ends 2066a and 2066b are conveniently positioned for measuring their movement by suitable measuring elements. This allows the torque sensor element 2000 to make efficient use of the space within the joint, as one or more measuring elements can be placed in a convenient location.

[0080] In the example, a torque sensor element according to the invention can be provided, which is suitable for the coverage of prior art torque sensor elements, for example... Figure 1 The torque sensor element is shown. For example, according to one example, Figure 4 The dashed lines in the middle represent Figure 1 The coverage area of ​​the prior art torque sensor. It can be seen that even though the arms 2064a and 2064b extend radially outward into the outer frame 2010, the structure of the torque sensor element 2000 allows it to still fit substantially within the contour. In this example, this is achieved by the second outer portion 2010b being narrower than the upper outer portion 2010a, and the arm 2064a extending substantially circumferentially and being narrow enough that, although the movement of the arm 2064a is an amplification of the movement of the first portion 2062a, the arm 2064a is generally kept within the area that would be filled by the lower outer frame portion 2010b if it had the same width as the upper outer frame portion 2010a. In this example, the second arm 2064b is also like this. Therefore, according to certain example torque sensor elements of the present invention, for example Figure 4 The torque sensor element shown can provide a greater degree of sensitivity with its slender arms 2064a and 2064b, while still being able to be accommodated in existing or standard-sized joints.

[0081] In an example embodiment of the second torque sensor element 2000, an applied torque of 1.6 N / mm results in a displacement of approximately 0.070 mm of the inner frame 2020 relative to the outer frame, and a displacement of approximately 1.38 mm of one or both of the first free end 2066a and the second free end 2066b. Therefore, the movement of the free ends 2066a and 2066b is approximately 20 times amplified by the movement between the outer frame 2010 and the inner frame 2020. Conversely, under the same applied torque, Figure 1 Implementations of existing art devices can produce displacement of the plates of capacitive sensors C1-C4, which is approximately nine times larger than the displacement between the outer ring 110 and the inner ring 120. Therefore, as described above, certain examples according to the invention provide an amplification of the relative rotation of the outer and inner frames, resulting in increased sensitivity to applied torque.

[0082] While providing amplified motion for more sensitive torque measurement, the overall structure of the exemplary torque sensor element (e.g., torque sensor element 2000) according to the invention provides sufficient rigidity to allow torque to be effectively transmitted in the joint. Furthermore, by providing beam devices, such as beam devices 2030a-c, stress can be effectively distributed within the exemplary torque sensor element, thus limiting the possibility of material strain. This can even be achieved in examples where gaps exist in the outer frame 2010, for example in… Figure 4 In the example, this allows the torque sensor element 2000 to minimize the hysteresis caused by material stress resulting from the applied torque. Therefore, the torque sensor element 2000 allows for accurate and reproducible torque measurements.

[0083] Furthermore, certain exemplary torque sensor elements according to the invention, such as the second torque sensor element 2000, allow for a low degree of deformation of the inner frame 2020 under typical torques that may be experienced in a robot joint. For example, in the same exemplary embodiment of the second torque sensor element 2000 discussed above, where the torque sensor element 2000 is formed of spring steel sheets, the maximum deformation of the inner frame 2020 is less than 0.07 mm under an applied torque of 1.6 Nm when the outer frame 2010 is fixed in place. This low degree of deformation of the inner frame 2020 is advantageous because it provides more effective control over the position of the second side of the joint relative to the first side of the joint. For example, in the joints of the arm of a robotic device, deformation of the inner and / or outer frames of the torque sensor in the joint will negatively affect how the arm's position is controlled.

[0084] Despite Figure 4In the example shown, gaps 2010c and 2010d in the outer frame 2010 represent points of complete breakage within the outer frame 2010. However, in other examples, the outer frame may include thinner portions of the outer frame 2010, allowing the arm to extend above or below a given thinner portion of the outer frame 2010. Therefore, arms 2064a and 2064b can be configured to extend radially outward even when the gaps between portions of the outer frame 2010 are not complete breaks within the outer frame 2010. In such examples, arms 2064a and 2064b may also be thinner to allow movement above or below a thinner portion of the outer frame. For example, the thinner portion of the outer frame may be substantially half the thickness of the remaining portion of the outer frame. The arm may also be substantially half the thickness of the remaining portion of the outer frame to allow movement above or below the thinner portion, while the total thickness of the torque sensor element remains constant.

[0085] In some examples, two measuring elements are provided, each for measuring the motion of a corresponding one of the first parts 2062a, 2062b, such as the motion of the free ends 2066a, 2066b of the arms, as described above. Providing two sensor elements allows for more reliable torque measurement by considering the motion of both the first arm 2064a and the second arm 2064b. For example, the measured values ​​can be averaged, or the difference between the measured values ​​can be taken, which can, for example, help to eliminate noise. In other examples, torque measurement may be based on the measurement of the motion of only one of the first and second arms, or typically based on the measurement of the motion of only one of the first and second parts. In such examples, there may be only one measuring element.

[0086] although Figure 4 Examples include two arms 2064a and 2064b, but in other examples, the torque sensor element may include only one arm extending from one of the first portion 2062a and the second portion 2062b, such as one of the first arm 2064a and the second arm 2064b. In other examples, the torque sensor element may include more than two arms, and torque measurement may be based on a measurement of the movement of each of more than two arms. For example, a third arm (not shown) may be connected to the center of the third connection portion 2060c, and the movement of the third arm may be measured to provide torque measurement alone or in combination with measurements of the movement of other arms (e.g., the first and second arms). In some such examples, further clearance may be provided in the outer frame to allow any additional arms to extend radially outward into the outer frame.

[0087] Despite Figure 4In the example shown, each of arms 2064a, 2064b extends through gaps 2010c, 2010d in the outer frame 2010, but in other examples, arms may be provided extending from, for example, the first or second portion but not radially outside the outer frame 2010. For example, the arm may extend from one of the first or second portions in any direction, such as radially or generally circumferentially, while remaining radially inside the outer frame. In some examples, the outer frame and / or inner frame may be shaped to accommodate the arm extending within the space between the inner and outer frames. For example, the outer and / or inner frame may include cut-out portions that provide sufficient space to accommodate the arm and allow movement of the arm when an applied torque causes relative rotation between the inner and outer frames.

[0088] Figures 6A-6D An exemplary joint 4000 including a second torque sensor element 2000 is shown. Joint 4000 is a joint in a robotic device and is an elbow joint between an upper arm 410 and a lower arm (not shown). Figure 6A and Figure 6B The perspective and side views of joint 4000 are shown in exploded form. Figure 6C and 6D Perspective and side views of the compact form of the joint 4000 are shown respectively.

[0089] Joint 4000 includes a cavity 4010 in the upper arm 410. Cavity 4010 is generally circular and houses the torque sensor element 2000 and other components of joint 4000. In use, the outer frame 2010 of the torque sensor element 2000 passes through a first series of holes 2012 in the torque sensor element 2000 (see...). Figure 4 The retaining element (not shown) inserted into the corresponding series of holes in the cavity 4010 is rigidly fixed to the upper arm 410. The bearing 4020, positioned above the torque sensor element 2000 during use, provides rigidity against torsional forces, i.e., forces that do not produce torque about the vertical axis through the central hole 4050 of the joint 4000.

[0090] The upper ring 4030 is housed within the bearing 4020 and is located on top of the torque sensor element 2000. In use, the upper ring 4030 is fixed to the inner frame 2020 of the torque sensor element 2000. The upper ring 4030 includes a protrusion 4032 on its lower surface. Figure 6BAs most clearly seen, protrusion 4032 facilitates the connection of the upper ring 4030 to the inner frame 2020. Protrusion 4032 includes holes (not shown) complementary to the second series of holes in the inner frame 2020, thereby allowing the upper ring 4030 to be secured to the inner frame 2020. The upper ring 4030 is configured to connect to the underside of a joint motor (not shown) for controlling the elbow joint 4000. Thus, the torque applied by the joint motor for controlling the elbow joint 4000 is transmitted through the torque sensor element 2000. The torque causes a small rotation between the outer frame 2010 and the inner frame 2020 and deforms certain portions of the torque sensor element 2000 in a measurable manner as described above to measure the torque applied to the joint 4000. Cavity 4010 includes a cut-off portion 4012 that allows a magnetic measuring element (see Figure 5 Located near the first and second free ends 2066a, 2066b, to measure the movement of arms 2062a, 2062b.

[0091] Especially from Figure 6B As can be seen, the torque sensor element 2000 has a low profile, which facilitates its inclusion within the joints of a robot, which may contain numerous mechanical and electronic components. Various features of the torque sensor element 2000 described above enable this low profile. For example, the stress distribution beam assembly 2030a-c allows the torque sensor element 2000 to be formed from thin steel sheets while still possessing sufficient stress resistance to withstand the typical torques used in the joints of robotic devices (e.g., joint 4000).

[0092] In cases where it is desired to measure torque in a joint subjected to high torque, a torque sensor can be used that employs multiple stacked torque sensor elements arranged according to the example described herein. For example, two... Figure 4 The second torque sensor elements 2000 shown can be placed one on top of the other (their center apertures 2050 aligned), making them effectively function as a single torque sensor element with twice the thickness and therefore twice the stress resistance. A torque sensor element with greater thickness means that for a given torque, the degree of rotation produced between the outer frame 2010 and the inner frame 2020 is reduced, and therefore the sensitivity of the torque sensor is reduced. Any number of torque sensor elements according to the examples described herein can be combined in this way to provide a torque sensor with suitable strength and sensitivity for a given application.

[0093] Figure 7 A simplified representation of an example robotic device 500 is shown, in which a torque sensor according to the example described herein can be used. Figure 7A side view of a robotic device 500 is shown. The robotic device 500 includes an actuated robotic arm 505, which includes a body 502, an end effector 512, and multiple joints. The body 502 may also be referred to as a base link. The robotic device 500 also includes a propulsion system (not shown) for actuating one or more joints, which may include one or more joint motors. The position of one or more joints is controlled to control the position and / or orientation of the end effector 512 in Cartesian space, allowing the end effector 512 to move within the environment in which the robotic device 500 is located. For example, where the position and orientation of the end effector 512 are controlled by the joints, the position and orientation of the end effector 512 (which may be referred to as the "pose" of the end effector 512 in some examples) can be controlled in 6-dimensional space.

[0094] In the example robotic device 500, the actuated robotic arm 505 includes six joints 514a-514f, which are configured to allow positioning of an end effector 512 having, for example, six degrees of freedom. The robotic device 500 includes six rotary joints and can therefore be referred to as a 6R robot. The joints 414a-414f of the actuated robotic arm 405 are connected by mechanical links or "links". Figure 7 A first link 515a is shown, mechanically connecting a first joint 514a to a second joint 515b. A second link 515b mechanically connects the second joint 514b to a third joint 514c. The robotic arm 505 also includes a third link 515c, a fourth link 515d, and a fifth link 515e, which respectively mechanically connect the third joint 514c to the fourth joint 514d, the fourth joint 514d to the fifth joint 514e, and the fifth joint 514e to a sixth joint 514f. The robotic device 500 may include other joints and / or links not shown in the figures. For example, as described above, in some examples, the robotic device may include one or more joints that allow translational (i.e., linear) motion in addition to joints that allow rotational motion. Each link may include a rigid, elongated member. Each link may be a single unit or multiple connected subunits. Each link may have solid and / or hollow portions. In one case, the link may include a hollow tube and / or a frame of a rigid material such as steel, aluminum, or carbon fiber. In some examples, the tool (not shown in the figure) may be mechanically coupled to the end effector 512.

[0095] Robotic device 500 is positioned on surface 570 defining an xy-plane. The xy-plane can be horizontal, such that the z-axis is a vertical axis. However, this is not the case in all examples. The position and / or orientation of the end effector 512 relative to this three-dimensional coordinate system can be controlled by controlling the rotation of one or more of joints 514a-514f. Each of joints 514a-514f is configured to rotate about at least one axis to allow the end effector 512 to move within a specific degree of freedom. For example, in a given configuration of robotic device 500, one or more of joints 514a-514f can rotate about an axis parallel to the z-axis to allow control of the position of the end effector 512 in the xy-plane. Furthermore, one or more of joints 514a-514f can be configured to rotate to control the position of the end effector 512 along the z-axis. In some examples, one or more of joints 514a-514f may include ball joints or double-joint assemblies that allow rotation about axes parallel to the z-axis and y-axis, respectively.

[0096] As described above, the joints 514a-514f of the actuated robotic arm 505 can be rotated by applying a corresponding joint torque to the joints 514a-514f. The joint torque is calculated by a controller (not shown) performing a control method (e.g., an impedance-based control method). The calculated joint torque is applied to the joints via a propulsion system, which may include one or more electric motors. For example, the propulsion system may include multiple electric motors, and one of the electric motors may be located in each of the joints 514a-514f.

[0097] The robot device 500 also includes one or more sensors for detecting the state of the robot device 400 and feeding it to a controller for use in a control method. The sensors include at least one torque sensor, which includes a torque sensor element according to an aspect of the invention described herein. Other sensors may, for example, detect corresponding joint angles of joints 514a-514f. A torque sensor including a torque sensor element according to the invention and a measuring element for measuring the deformation of the torque sensor element may be present in one or more, for example, all joints 514a-514f. For example, any one of joints 514a-514f may have the above reference. Figures 6A-6D The characteristics described.

[0098] The drive control system (not shown) of the robot device 500 can control the torque applied by one or more motors arranged at joints 514a-514f in response to signals received from a controller (not shown). The controller may include one or more processors, including one or more microprocessors, a central processing unit and / or a graphics processing unit, and one (or more) memories. The controller is communicatively coupled to the example control unit to control the movement of the robot device. This coupling may be achieved via a system bus (not shown). For example, the controller can provide a desired joint torque, which is translated into joint actuator commands by the joint control system assembly.

[0099] The examples above should be understood as illustrative. Further examples are also contemplated. Any feature described with respect to any example may be used alone or in combination with other features described, and may also be used in combination with one or more features of any other example, or in any combination of any other example. Furthermore, equivalents and modifications not described above may be employed without departing from the scope of the invention, the scope of which is defined in the appended claims.

Claims

1. A torque sensor element for measuring torque applied to a joint, the torque sensor element comprising: The outer frame connects to the first side of the joint; The inner frame connects to the second side of the joint; as well as A compliant device connects the outer frame to the inner frame; The compliance device includes: A first member and a second member, each extending between and connecting the outer frame to the inner frame, and each member being elastic and deformable to allow at least some relative rotation between the outer frame and the inner frame in response to torque applied to the joint; and A connecting structure extends between the first member and the second member and connects the first member and the second member, the connecting structure including a first portion located between the first member and the second member, the first portion being configured to move by an amount determined by the degree of relative rotation between the outer frame and the inner frame caused by a torque applied to the joint in response to deformation of the first member and / or the second member.

2. The torque sensor element according to claim 1, wherein, The movement of the first part of the connection structure in response to the deformation of the first member and / or the second member includes at least a rotational component.

3. The torque sensor element of claim 1, comprising a first arm connected to the first portion, wherein, The first arm is configured to move by an amount determined by the degree of relative rotation between the outer frame and the inner frame caused by the torque applied to the joint.

4. The torque sensor element according to claim 3, wherein, The first arm extends in a direction away from the inner frame.

5. The torque sensor element according to claim 4, wherein, The outer frame includes a gap, and the first arm extends through the gap.

6. The torque sensor element according to any one of the preceding claims, wherein, The connection structure includes at least one linking element that links the first member or the second member to the first portion and is configured to facilitate movement of the first portion when torque is applied to the joint.

7. The torque sensor element according to claim 6, wherein, The connection structure includes a first linking element configured to connect the first member to the first portion and a second linking element configured to connect the second member to the first portion, wherein each of the first linking element and the second linking element is configured to facilitate movement of the first portion when torque is applied to the joint.

8. The torque sensor element according to any one of claims 1 to 5, wherein, One or more beam elements connect the outer frame to the inner frame, wherein each of the one or more beam elements includes one or more connecting members that connect the outer frame to the inner frame.

9. The torque sensor element according to any one of claims 1 to 5, comprising a third member and a fourth member, each member extending between and connecting the outer frame to the inner frame, and each of the third member and the fourth member being elastic and deformable to allow at least some relative rotation between the outer frame and the inner frame in response to a torque applied to the joint; and A second connecting structure extends between the third and fourth members, the connecting structure including a second portion located between the third and fourth members, the second portion being configured to move by an amount determined by the degree of relative rotation between the outer and inner frames caused by a torque applied to the joint in response to deformation of the third and / or fourth members.

10. The torque sensor element according to claim 9, wherein, The second part of the connection structure includes a second arm configured to move by an amount determined by the degree of relative rotation between the outer frame and the inner frame caused by the torque applied to the joint.

11. A torque sensor for measuring torque applied to a joint, the torque sensor comprising: Torque sensor element according to any one of claims 1 to 10; as well as A measuring element is used to measure the amount of movement of a first portion of the torque sensor element in response to the relative rotation between the outer and inner frames caused by the torque applied to the joint, thereby measuring the torque applied to the joint.

12. The torque sensor according to claim 11, wherein, The measuring element is configured to measure the rotation of the first portion, thereby measuring the torque applied to the joint.

13. The torque sensor according to claim 11 or 12, wherein, The measuring element includes a magnetic measuring element configured to measure the movement of the first portion by measuring the change in the magnetic field caused by the movement of the first portion of the connection structure.

14. A robotic device, comprising: main body; An end effector, connected to the body via one or more joints; A propulsion system that drives the one or more joints to control the state of the robotic device; as well as The torque sensor according to any one of claims 11 to 13 is arranged to measure the torque applied to one of the one or more joints.

Images