Force torque sensor for robotic systems in bioprocessing environments
Patent Information
- Application Number
- CN202480084577.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2023-11-12
- Filing Date
- 2024-11-12
- Publication Date
- 2026-10-13
Smart Images
Figure CN122910399A_ABST
Abstract
Description
Cross-references to related applications
[0001] This application claims the benefit of U.S. Provisional Application No. 63 / 598,116, filed November 12, 2023, which is incorporated herein by reference in its entirety. Background Technology Technical Field
[0003] Various aspects of this disclosure relate to force and torque sensors, such as force and torque sensors for robotic systems in biological processing environments. Background Technology
[0005] Biological laboratory processing requires the handling of a wide variety of samples. These processes include transferring liquids from one location to another, centrifuging samples to separate components, precisely altering temperatures to catalyze specific reactions, and so on. Because of the sheer volume of processing required in biology, and because each laboratory typically needs a unique subset of these processes, achieving full automation of biological processing has proven extremely difficult.
[0006] Sensors attached to robotic systems in biological processing environments provide tactile feedback required for various processes. For example, robotic systems can use force-torque sensors to calibrate and / or determine the position of associated tools within the biological processing environment. Attached Figure Description
[0007] The accompanying drawings are incorporated herein by reference and form part of the specification.
[0008] Figure 1 A biological treatment environment according to some embodiments is shown.
[0009] Figure 2A , Figure 2B , Figure 2C A force-torque sensor according to some embodiments is shown.
[0010] Figure 3 A circuit architecture according to some embodiments is shown.
[0011] Figure 4 A method for detecting contact in a robotic system according to some embodiments is shown.
[0012] Figure 5A , Figure 5B , Figure 5C , Figure 5D and Figure 5E A capacitive force-torque sensor according to some embodiments is shown.
[0013] Figure 6 A block diagram of a sensor according to some embodiments is shown.
[0014] Figure 7 Methods according to some embodiments are shown.
[0015] Figure 8 A computer system according to some embodiments is shown.
[0016] In the accompanying drawings, similar reference numerals usually denote the same or similar elements. Additionally, the leftmost numeral in the reference numerals typically indicates the drawing in which the reference numeral first appears. Detailed Implementation
[0017] This specification discloses one or more aspects of the features incorporated herein. The disclosed aspects are merely illustrative. The scope of the invention is not limited to the disclosed aspects. The invention is defined by the appended claims.
[0018] The aspects described herein, and the references to "an aspect," "aspect," "example aspect," "exemplary aspect," etc., indicate that the described aspect may include a particular feature, structure, or characteristic, but not every aspect necessarily includes that particular feature, structure, or characteristic. Furthermore, such phrases do not necessarily refer to the same aspect. Moreover, when a particular feature, structure, or characteristic is described in conjunction with an aspect, whether explicitly stated or not, it is understood that the effect of combining it with other aspects on such feature, structure, or characteristic is within the knowledge of those skilled in the art.
[0019] For ease of description, this document uses spatially relative terms such as “below,” “under,” “lower,” “above,” and “upper” to describe the relationship between one element or feature and another, as shown in the figures. In addition to the orientations depicted in the figures, the spatially relative terms are intended to cover different orientations of the device in use or operation. The device may be oriented in other ways (rotated 90 degrees or otherwise), and the spatially relative descriptors used herein will be interpreted accordingly.
[0020] As used herein, the terms “about,” “substantially,” or “approximately” indicate the value of a given quantity that may vary based on a particular technique. Based on a particular technique, “about,” “substantially,” or “approximately” may indicate the value of a given quantity that varies within, for example, 1% to 15% of that value (e.g., ±1%, ±2%, ±5%, ±10%, or ±15% of that value).
[0021] Example biological treatment environment
[0022] Biological processing environments can include various locations containing equipment used in a given process. Robotic systems can transfer materials to the necessary locations within a biological processing environment. However, due to tolerances in the manufacturing process, robotic systems may struggle to determine the precise locations of equipment and materials. Furthermore, given the size and fragility of biological samples and associated equipment, accuracy is critical to avoid contaminating, damaging, or destroying the biological samples or associated equipment. Current solutions for calibrating the location of objects in biological processing environments use conductivity probes. However, conductivity probes are single-purpose tools and only work with conductive components. Therefore, conductivity probes cannot be used to calibrate or measure the location of plastic or glass objects. However, many objects used for biological sample processing are non-conductive, such as pipette tips and sample well plates.
[0023] Sensor systems, such as force-torque sensors according to the aspects described herein, provide tactile feedback to the robotic system, thereby allowing the robotic system to "feel" the position of individual components. For example, a force-torque sensor can provide measurements when the robotic system contacts the edge of a perforated plate, thereby allowing the robotic system to determine the position of the perforated plate.
[0024] Figure 1 A biological processing environment 100 according to some embodiments is illustrated. Environment 100 may include a frame 101 to which other components are mounted. Biological processing environment 100 may include a robotic system 102. Robotic system 102 includes a robotic arm 103 movable around biological processing environment 100. Biological processing environment 100 may also include a platform / tabletop 104 for mounting objects, the tabletop including multiple tabletop slots 105 for receiving devices, sample containers, and / or other biological system components. Although... Figure 1 A robotic system 102 is shown mounted on a worktable 104, but those skilled in the art will recognize that the robotic system 102 can be mounted on any part of the frame 101. In some embodiments, the bioprocessing environment 100 includes a tool loading station 106 for storing one or more tools 112 when not in use by the robotic system 102.
[0025] In some embodiments, the robot system 102 may include a tool changer configured to engage with corresponding connection points on one or more tools 112. This tool changer allows the robotic arm 103 to automatically change between tools 112 in response to commands instructing the robotic arm 103 to perform different functions. In some embodiments, the robot system 102 further includes a force-torque sensor 108. The force-torque sensor 108 may be mounted between the robotic arm 103 and the tool changer 110. By placing the force-torque sensor 108 between the robotic arm 103 and the tool changer 110, the sensor becomes universal / tool-independent. That is, force-torque sensing capability can be provided for all tools without the tool itself containing such a sensor.
[0026] When oriented from the mounting end of the robotic system 102, the proximal end of the force-torque sensor 108 can be attached to the distal end of the robotic arm 103, while the distal end of the force-torque sensor 108 can be attached to the proximal end of the tool changer 110. The tool changer 110 can be configured to connect to and replace one or more tools 112 at the tool loading station 106. The robotic system 102 can use one or more tools 112 to perform biological treatments and / or calibrate the surrounding environment. In embodiments where the tool changer 110 is not used (e.g., where the tool 112 must be replaced manually), the force-torque sensor 108 can be directly mounted between the robotic arm 103 and the tool 112.
[0027] Force and torque sensor 108 can measure the force and / or torque applied to tool changer 110 and tool 112. Because force and torque sensor 108 is positioned between tool 112 and robotic arm 103, any force or torque acting on tool 112 is mechanically transmitted to force and torque sensor 108, allowing for direct measurement in real time. As will be described below, force and torque sensor 108 includes multiple individual sensing elements that combine to allow force and torque sensor 108 to measure motion in multiple dimensions.
[0028] In some embodiments, robot system 102 may use force-torque sensor 108 to calibrate the position of components in bioprocessing environment 100. For example, robot system 103 may slowly move around environment 100 until tool 112 (e.g., a calibration rod) contacts a static component in environment 100, such as one side of a tabletop slot among a plurality of tabletop slots 105. When tool 112 contacts the static component, force-torque sensor 108 can detect the obstruction by measuring the torque experienced by the tool as the tool mechanically transmits motion to the attached force-torque sensor 108. In some cases, the above process may be repeated until all sides of the tabletop slot are located. Such positions can be used to develop an accurate virtual map of environment 100, eliminating positional uncertainties caused by dimensional variations due to device manufacturing tolerances. This, in turn, allows for more precise interaction between tools and devices in bioprocessing environment 100 during operation than is possible with existing tools. Similarly, robot system 102 may use force sensor 108 to determine the precise position of tool 112 in tool loading station 106.
[0029] In some embodiments, the force-torque sensor 108 can enhance the liquid handling capabilities of the robotic system 102. For example, the optimal location for collecting and dispensing liquid in a well is a few millimeters above the bottom surface of the well. As described below, the force-torque sensor 108 can accurately detect when the tool contacts the bottom surface of the well without substantially pressing into or substantially compressing the tool 112, and moves the tip of the liquid handling tool (such as a pipette) away from the bottom surface by an optimal amount. Thus, some embodiments of the force-torque sensor 108 have a sensitivity of up to approximately 2.5 grams. This sensitivity allows for detection when the pipette tip has just touched the bottom of the microplate well without causing the pipette tip to warp upon contact with the bottom of the well.
[0030] Additionally, the force-torque sensor 108 can be used for error detection. For example, if the robotic system is not properly aligned with a component such as a pipette tip, the force-torque sensor 108 can measure the peak of the mechanical force before the expected peak of the force, thereby indicating an alignment error.
[0031] Example strain gauge force-torque sensor
[0032] Figure 2A , Figure 2B and Figure 2C Elements of a force-torque sensor 200 according to some embodiments are shown. For example... Figure 2AAs shown, the force-torque sensor 200 may include a rigid housing 202 and a printed circuit board 204. The rigid housing 202 may include one or more strain gauges 206 mounted thereon. The rigid housing 202 may be made of a rigid metal such as aluminum, steel, or titanium. In some embodiments, the rigid housing 202 partially or completely surrounds the printed circuit board 204, such that the printed circuit board 204 is at least partially or completely located within the rigid housing 202.
[0033] In some embodiments, the rigid housing 202 includes an inner portion 208, an outer portion 210, and a plurality of beams 212. The inner portion 208 and the outer portion 210 may be concentric. The plurality of beams 212 may span between the inner portion 208 and the outer portion 210. Although Figure 2A Only one set of strain gauges 206 on one beam 212 is shown, but those skilled in the art will recognize that a set of strain gauges 206 may be present on multiple beams 212 of the rigid housing 202.
[0034] A set of measuring axes can be defined on the rigid housing 202 such that measurements along this set of axes can be converted into force and / or torque measurements along a principal axis (e.g., x, y, or z). For example, a set of three measuring axes can be defined such that the sensor 200 measures force in the z-direction and torque in the x and y directions. In another non-limiting example, a set of six measuring axes can be defined such that the sensor 200 measures both force and torque in the x, y, and z directions. The rigid housing 202 can be designed to flex and / or bend along the measuring axes under the applied force.
[0035] In some embodiments, each of the plurality of beams 212 constitutes a measurement axis. The beams generate mechanical deflection points to concentrate strain at specific locations on the beam while maintaining strength. Thicker beams imply higher overall strength and stiffness, but lower sensitivity, thus the beam thickness can be optimized as needed. Each of the plurality of beams 212 may have a set of strain gauges 206 mounted thereon.
[0036] The strain gauges in a set of strain gauges 206 may be glued or otherwise attached to the rigid housing 202. In order to read the measurement results from the set of strain gauges 212, each strain gauge in the set of strain gauges 206 must be electrically connected to the printed circuit board 204.
[0037] In some embodiments, the leads from each strain gauge in a set of strain gauges 206 are directly soldered to the printed circuit board 204. In other embodiments, a flexible member 214 provides an electrical connection between the set of strain gauges 206 and the printed circuit board 204. For example, a first end of the flexible member 214 may be connected to the rigid housing 202, and a second end of the flexible member 214 may be connected to the printed circuit board 204. The leads from each strain gauge in the set of strain gauges 206 may be soldered to the first end of the flexible member 214. This flexible connection simplifies the assembly process.
[0038] When the rigid housing 202 is compressed along the measuring axis, the resistance of each strain gauge in the set of strain gauges 206 changes in response to the applied force. The change in resistance results in a change in the voltage measured on the set of strain gauges 206.
[0039] Each set of strain gauges 206 can be configured as a bridge circuit. Figure 2B An example configuration of a set of strain gauges is shown. A set of strain gauges 206 can form a Wheatstone bridge 216. In some embodiments, two strain gauges are attached to the top side of the rigid housing 202, and two strain gauges are attached to the bottom side of the rigid housing 202. In some other embodiments, a first pair of strain gauges is attached to the top side of the rigid housing 202, and a second pair of strain gauges is attached to the bottom side of the rigid housing 202. When the rigid housing 202 is deflected / compressed under an applied force, the measured voltage on the Wheatstone bridge 216 changes. The measured voltage can be amplified and converted into a force and / or torque measurement along a principal axis (e.g., the x, y, or z axis).
[0040] Figure 2C A printed circuit board 204 according to some embodiments is shown. Printed circuit board 204 may include both analog electronics and high-frequency digital electronics. If high-frequency digital circuitry and sensitive low-frequency analog circuitry are mixed together on printed circuit board 204, interference may occur between these components. To ensure that return current from analog circuitry does not cross the digital signal path, printed circuit board 204 may be divided into regions 218 and 220, thereby mitigating mixed-signal interference. Region 218 may contain analog components such as sensing subcircuits, voltage regulators, and analog-to-digital converters. Region 220 may contain digital components such as microcontrollers and / or CAN buses.
[0041] Figure 3 A circuit architecture 300 according to some embodiments is shown. The circuit architecture 300 can, for example, amplify the voltage difference measurement results of each set of strain gauges 206.
[0042] As described above, a set of strain gauges can form a circuit bridge. In circuit 300, circuit bridge 302 provides the measured voltage signal. To reduce noise, the signal is filtered by filter 304. Filter 304 can attenuate signals greater than a predetermined value (such as approximately 1,000 Hz). In some embodiments, filter 304 is a low-pass RC filter.
[0043] The filtered signal can be amplified by amplifier 306. In some embodiments, amplifier 306 provides a gain of, for example, about 1,000x. To reduce noise introduced by amplifier 306, the signal can pass through a second low-pass filter 308. In some embodiments, filter 308 attenuates frequencies higher than, for example, about 500 Hz.
[0044] The measured, filtered, and amplified voltage signal can then be converted into a binary signal by the analog-to-digital converter 310. The microcontroller 312 can process the binary signal and, in some cases, determine the action to be taken based on the signal value. In some cases, the microcontroller 112 sends commands to the robot system 110 via the CAN bus.
[0045] In some embodiments, the resistance of each resistor (e.g., a strain gauge) in the circuit bridge 302 is equal. In this configuration, when no force is applied to the set of strain gauges, the voltage signal measured by the circuit bridge 302 should be zero. However, due to manufacturing defects in the set of strain gauges (e.g., inconsistent resistance values), a baseline signal may exist. The digital-to-analog converter 314 can convert the baseline signal (digital) read by the microcontroller 312 back into an analog signal. The analog baseline signal can be added to the voltage measured by the circuit bridge 302 to calibrate the measured voltage signal.
[0046] Figure 4 A method 400 for detecting contact in a robotic system according to some embodiments is shown. Method 400 includes steps 402, 404, and 406.
[0047] When a force is applied to the force-torque sensor or a component attached to it (such as a tool changer or tool), the sensor measures voltage. Because of noise (typically electromagnetic interference) present in the sensor, it measures a baseline noise value when no force is applied.
[0048] In step 402, the force-torque sensor measures the voltage value during operation of the robot system. The force-torque sensor can measure the applied force or baseline noise value. In some embodiments, the measured voltage value is smoothed by applying an exponential moving average function to the measured value.
[0049] In step 404, the measured sensor value is compared to the contact detection value. The contact detection value provides a threshold that allows the processor to distinguish between noise signals and force or torque signals. For example, a measured sensor value above the contact detection value is interpreted as a contact detection signal, and a value below the contact detection value is interpreted as a noise signal. The mean and standard deviation of the measured sensor noise can be calculated before or during sensor deployment. In some cases, the contact detection value differs from the average noise value by at least four standard deviations.
[0050] In step 406, the sensor processes the contact detection signal and sends motion commands to the controller in the robot system based on the contact detection signal. In some cases, the contact detection signal indicates a collision, and the robot system stops moving. In some cases, the contact detection signal indicates non-collision direct contact, and the robot system records the contact and continues to the next step in its processing flow. In some cases, the contact detection signal is used to calibrate the position of components in the biological processing environment, as described above.
[0051] Figure 4 The method steps can be performed in any conceivable order, and it is not necessary to perform all the steps. Furthermore, the above... Figure 4 The method steps described are merely examples, not limitations. That is, based on the reference... Figures 1 to 3 The description of each aspect envisions further methods, steps, and functions.
[0052] Example capacitive force and torque sensor
[0053] Figure 5A , Figure 5B , Figure 5C , Figure 5D and Figure 5E A capacitive force-torque sensor 500 according to some embodiments is shown. Sensor 500 is... Figure 2A , Figure 2B and Figure 2CAn alternative embodiment of sensor 200 is shown. Instead of the strain gauge described above, sensor 500 identifies the force and / or torque acting on sensor 500 based on the capacitance change of one or more parallel-plate capacitors of sensor 500. Sensor 500 can be integrated into a robotic system, such as robot system 102. In some embodiments, sensor 500 is attached between a robotic arm and a tool that can be used in the robotic system. In this arrangement, sensor 500 can be used to detect the force and / or torque applied to the tool. In some embodiments, the tool can be indirectly attached to the robotic arm via another element, such that sensor 500 can be placed anywhere between the robotic arm and the tool (e.g., before or after the other element). In some embodiments, sensor 500 is attached between the robotic arm of the robotic system and a tool changer. In this arrangement, sensor 500 can be used to detect the force or torque applied to the tool attached to the tool changer.
[0054] Sensor 500 may include a housing 502 and a printed circuit board (PCB) 504. Housing 502 may include elements forming one side of one or more parallel-plate capacitors, while PCB 504 may include elements forming the opposite sides of one or more parallel-plate capacitors. Housing 502 may include a material designed to flex but not plastically deform under applied forces, such that the material returns to its original shape when the force is removed. For example, housing 502 may be made of a metal such as aluminum, steel, titanium, etc. Figure 5A As shown, the housing 502 partially or completely surrounds the printed circuit board 504, such that the printed circuit board 504 is at least partially or completely located within the housing 502. Further details regarding the relative positioning between the housing 502 and the printed circuit board 504 will be discussed below.
[0055] A set of measuring axes can be defined on housing 502 such that measurements along this set of axes can be converted into force and / or torque measurements along a principal axis (e.g., x, y, or z). For example, a set of three measuring axes can be defined such that sensor 500 measures force in the z-direction and torque in the x and y directions. In another non-limiting example, a set of six measuring axes can be defined such that sensor 500 measures both force and torque in the x, y, and z directions. Although shown as having a generally circular configuration, those skilled in the art will recognize that housing 502 can have other shapes that allow measurements along multiple axes.
[0056] Figure 5BFurther details of a housing 502 according to some embodiments are shown. The housing 502 may include an inner portion 506, an outer portion 508, and a plurality of beams 510. The inner portion 506 and the outer portion 508 may be nested. In some embodiments, the inner portion 506 and the outer portion 508 may have substantially the same shape. In some embodiments, the inner portion 506 and the outer portion 508 may be substantially concentric. The inner portion 506 may present a shape other than... Figure 5B Shapes other than those shown. For example, the inner portion 506 may have a polygonal shape and may have a hollow or solid center. The inner portion 506 may typically be shaped and positioned to provide support for the plurality of beams 510 and the PCB 504. For example, each of the plurality of beams 510 may span between the inner portion 506 and the outer portion 508. In some embodiments, the PCB 504 may be attached to the inner portion 506 via a set of screws inserted into threaded holes in the inner portion 506.
[0057] The housing 502 may also include first conductive plates 512. Each of the first conductive plates 512 may be positioned adjacent to the outer portion 508 via a flexure 513, the flexure being designed to move the first conductive plate 512 when a force is applied to the outer portion 508. The first conductive plates 512 may include a conductive material, such as a metal or metal alloy. In some embodiments, the first conductive plates 512 are made of the same material as the housing 502. The first conductive plates may have a rough or smooth surface. Although the first conductive plates 512 are in Figure 5B The first conductive plate has a circular shape, but those skilled in the art will understand that it can be other shapes, such as rectangular or elliptical.
[0058] Figure 5C A cross-sectional view of a sensor 500 according to some embodiments is shown. This cross-sectional view shows an example positioning of a housing 502 relative to a PCB 504 according to some embodiments. The PCB 504 may include a second conductive plate 514. In some embodiments, the second conductive plate 514 may be embedded in the PCB 504 such that the outer surface of the second conductive plate is coplanar with the outer surface of the PCB 504. In some other embodiments, the second conductive plate 514 may extend beyond the surface of the PCB 504. The PCB 504 may further include an inner layer 515, which in... Figure 5E It is shown in detail in the text.
[0059] exist Figure 5CIn the illustrated embodiment, PCB 504 is attached to the internal portion 506 via attachment members 517 (e.g., screws). When PCB 504 is attached in this manner, the first conductive plate 512 and the second conductive plate 514 can be aligned and positioned a distance D from each other. When an appropriate voltage is applied, this creates a set of parallel-plate capacitors. In some aspects, the first conductive plate 512 can be grounded while the second conductive plate 514 is voltage-energized to measure the capacitance between the first and second conductive plates 512. In some aspects, the first conductive plate 512 can be grounded along with other components of the robotic system, eliminating the need for special connections to the first conductive plate 512. Figures 5A to 5E In the illustrated embodiment, sensor 500 includes a set of three capacitors. Other embodiments may have more or fewer capacitors. The capacitors may be positioned to measure force or torque on different measurement axes of sensor 500 (e.g., x-axis, y-axis, or z-axis). For example, when an external force is applied to housing 502, components of housing 502 may flex. This changes the distance D between at least one of the first conductive plates 514 and at least one corresponding second conductive plate 516, which in turn changes the capacitance of at least one capacitor in the set of capacitors. Each capacitor in the set of capacitors may be uniformly spaced around the outer portion 504 of sensor 500. The amount of flexing of each first conductive plate 514 may depend on the location where the force is applied to housing 502. For example, a conductive plate located near the point where the force is applied may flex more than a conductive plate located on the opposite side of the sensor to the applied force. The relative change in capacitance of each capacitor in the set of capacitors can be used to determine the value or direction of the applied force or torque. (Refer to below) Figure 6 Further discussion is given regarding the determination of force / torque and its direction based on capacitance. Additional sensor elements, such as those mentioned in the reference... Figure 5D and Figure 5E As described, it can detect changes in capacitance.
[0060] Figure 5D and Figure 5E Further details of PCB 504 according to some embodiments are shown. In some embodiments, such as Figure 5D As shown, each of the second conductive plates 514 is surrounded by a protective ring 516. A non-conductive region 518 separates the conductive plates 514 from the protective ring 516. The non-conductive region 518 may include areas of the PCB 504 where conductive material (such as copper) has been etched away. The second conductive plates 514 and the protective ring 516 can receive an input voltage V from a power source (not shown). inThe input voltage can charge the capacitor. Although a guard ring is not required, including them and applying the same input voltage to the guard ring shifts any edge field to the outer edge of the guard ring, and thus linearizes the electric field at the edge of the second conductive plate 514. This field linearization can improve sensitivity and more accurate capacitance readings. The width of the guard ring 516 and the non-conductive region 518 can be selected to achieve the electric field linearization effect. For example, in some embodiments, the diameter of the second conductive plate 514 can be about 2 to 4 cm, and the width of the guard ring 516 and the non-conductive region 518 can be about 3 to 10 mm. The inner layer 515 of the PCB 504, such as Figure 5E As shown, one or more protection plates 520 may be included, which isolate the second conductive plate 514 from electronic noise generated in other parts of the PCB 504. The protection plates 520 may be positioned parallel to the second conductive plate 514. Similar to the protection ring 516, the protection plate 520 may be maintained at the input voltage V applied to the second conductive plate 514 during capacitor charging. in The same input voltage. While a protection plate is not required, including one helps reduce the effects of potential edge fields. The protection plate 520 may include a conductive material and may have approximately the same dimensions as the second conductive plate 514. In other embodiments, the protection plate 520 may be smaller or larger than the second conductive plate 514.
[0061] PCB 504 further includes a capacitive sensing element 522. The capacitive sensing circuit 522 measures the capacitance of a parallel-plate capacitor formed by a first conductive plate 512 and a second conductive plate 514. In some embodiments, capacitance is measured by determining the time taken for the capacitor to reach a threshold during charging / discharging. The capacitive sensing element 522 can be configured to measure multiple capacitors simultaneously. If the capacitive sensing element 522 cannot simultaneously measure each capacitor included within the sensor 500, one or more additional capacitive sensing elements can be added to PCB 504. References below... Figure 6 More details are provided regarding capacitive sensing elements.
[0062] PCB 504 may also include a microcontroller 524. The microcontroller 524 can receive capacitance measurements from the capacitive sensing element 522. In some embodiments, the microcontroller 524 compares the measured capacitance value with a previous capacitance value to determine whether a force has been applied to the sensor 500. When the sensor 500 is integrated into a robot system, the microcontroller 524 can send instructions to components of the robot system when a force (e.g., a change in capacitance) is detected. (Refer to below...) Figure 6 More details are provided regarding the operation of the microcontroller.
[0063] Figure 6A block diagram of the electrical components in a capacitive force-torque sensor 600 according to some embodiments is shown. The sensor 600 may include one or more capacitors 602, a capacitive sensing element 604, a microcontroller 606, and a controller local area network (CAN) bus transceiver 608.
[0064] A power supply (not shown) can power one or more capacitors 602, such that one plate is grounded (i.e., maintained at a constant voltage) and the other plate receives the input voltage. In some embodiments, the one or more capacitors 602 correspond to those referenced above. Figures 5A to 5E The first conductive plate 512 and the second conductive plate 514 described herein form a parallel-plate capacitor. One or more capacitors 602 may be charged / discharged by a resistor or, in an alternative embodiment, by an inductor.
[0065] When one or more capacitors 602 undergo a charge-discharge cycle, they transmit data to the capacitive sensing element 604. In some embodiments, the capacitive sensing element 604 corresponds to the reference above. Figures 5A to 5E The described capacitive sensing element 522. Capacitive sensing element 604 may include a chip or a series of circuits designed to convert capacitive signals into digital signals. In some embodiments, capacitive sensing element 604 measures the voltage of one or more capacitors 602 during discharge and determines the amount of time it takes for the voltage to reach a threshold. These values are then used to determine the capacitance of each capacitor 602. In some embodiments, capacitive sensing element 604 includes one or more reference capacitors. The measured capacitance of each capacitor 602 may be compared to the capacitance of one or more reference capacitors to account for environmental effects, such as temperature. Capacitive sensing element 604 may be further configured to perform signal post-processing, such as linearization and temperature compensation. Capacitive sensing element 604 may include readily available sensing elements, such as the ScioSense PCAP04 sensor. While sensor 600 shows three capacitors and one capacitive sensing element, those skilled in the art will understand that more or fewer capacitors and more capacitive sensing elements may be present.
[0066] The capacitive sensing element 604 can send the measured capacitance value to the microcontroller 606. In some embodiments, the microcontroller 606 corresponds to the reference above. Figures 5A to 5E The microcontroller 524 is described. Microcontroller 606 can compare a real-time capacitance value to a previous value (e.g., a single value or an average value) or a baseline value to determine if a capacitance change has occurred. In some embodiments, the previous value can be represented as a range, and if the real-time capacitance value falls outside that range, the microcontroller only detects a capacitance change. This helps to address noise (e.g., natural fluctuations in capacitance) in the capacitive sensing element 604.
[0067] In some embodiments, the microcontroller 606 can determine the direction of the force and / or torque by comparing the capacitance values measured from each capacitor in the capacitor set 606. For example, if the first capacitor has a higher capacitance value than the second or third capacitor, it can indicate that a force has been applied near the first capacitor. The relative change in capacitance can be calibrated to determine the direction of the force or torque relative to the aforementioned measurement axis. For example, a calibration device can apply a known force to the sensor 600 in a known direction while measuring the capacitance change of each capacitor in the set. To determine the direction of the force, the matrix containing the sensor values can be inverted.
[0068] In some embodiments, the sensor 600 may be incorporated into the arm of the robot system and used to detect when the arm or associated component of the robot system comes into contact with or otherwise contacts an obstacle or other element in the robot system.
[0069] If microcontroller 606 detects a capacitance change in one or more of the capacitors in capacitor 602, the microcontroller can send a contact detection signal to other components of the robot system. For example, microcontroller 606 can send the contact detection signal to the controller of the robotic arm via CAN bus transceiver 608. In some cases, the capacitance change relative to a previous / baseline value indicates a collision, and the robot system stops moving. In some cases, the capacitance change relative to a previous / baseline value indicates non-collision direct contact, and the robot system records the contact and continues to the next step in its processing flow. In some cases, the capacitance change is used to calibrate the position of components in the biological processing environment, as described above.
[0070] The microcontroller 606 can further use measured capacitance changes to control the electromagnetic tool changer. For example, a capacitance change can indicate that the tool changer has made contact with the desired tool. In this case, the microcontroller 606 can send a signal to the tool changer to activate the electromagnet that connects the tool to the robotic arm via electromagnetic force. Similarly, to release the tool, a capacitance change can indicate that the tool is in contact with the tool holder. The microcontroller can send a signal to the tool changer to deactivate the electromagnet, thereby releasing the tool.
[0071] Figure 7 A flowchart of a method 700 according to one embodiment is shown. Method 700 can be implemented using sensors in a robotic system, such as capacitive force-torque sensors attached to a robotic arm. See reference... Figures 5A to 5E and Figure 6 As described, the capacitive force-torque sensor detects the applied force by measuring the change in capacitance when a component of the sensor flexes in response to the applied force.
[0072] In step 702, the capacitance of one or more capacitors in the sensor is measured during operation of the robot system. The capacitance can be measured using one or more capacitance sensing elements integrated into a printed circuit board, as shown in the reference. Figure 5D As described.
[0073] In step 704, the measured (e.g., real-time) capacitance is compared to a previous capacitance value. The previous value could be the last measured capacitance or the average of the last few capacitance measurements. In some embodiments, a threshold that accounts for noise and / or natural variations in capacitance is added to and / or subtracted from the previous capacitance value to create a range of previous capacitance values. For improved robustness, the measured capacitance can be compared to this range.
[0074] If the measured capacitance is no different from the previous value (or a range of previous values), no force is detected, and method 700 returns to step 702. Alternatively, if the measured capacitance differs from the previous value or a range of previous values, a force is detected, and at step 706 the sensor sends instructions to other components of the robot system. For example, the sensor may send further motion instructions to the robotic arm or turn an electromagnet on / off in a tool changer.
[0075] The above Figure 7 The method steps described are merely examples, not limitations. That is, based on the reference... Figures 5A to 5E and Figure 6 The description of each aspect envisions further methods, steps, and functions.
[0076] Figure 8 Computer system 800 is illustrated. One or more computer systems 800 may be used, for example, to implement any of the embodiments discussed herein, as well as combinations and sub-combinations thereof, such as for strain gauge signal processing and / or the response of a robotic system to strain gauge signals.
[0077] Computer system 800 may include one or more processors (also called central processing units or CPUs), such as processor 804. Processor 804 may be connected to communication infrastructure or bus 806.
[0078] The computer system 800 may also include user input / output devices 803, such as monitors, keyboards, indicators, etc., which can communicate with communication infrastructure 806 through user input / output interfaces 802.
[0079] One or more processors in processor 804 may be graphics processing units (GPUs). In one embodiment, the GPU may be a processor that is a dedicated electronic circuit designed to process mathematically intensive applications. The GPU may have a parallel architecture that is efficient for parallel processing of large blocks of data, such as mathematically intensive data commonly found in computer graphics applications, images, videos, etc.
[0080] The computer system 800 may also include main or primary memory 808, such as random access memory (RAM). Main memory 808 may include one or more levels of cache. Main memory 808 may store control logic (i.e., computer software) and / or data therein.
[0081] The computer system 800 may also include one or more auxiliary storage devices or memories 810. Auxiliary storage 810 may include, for example, a hard disk drive 812 and / or a removable storage device or drive 814. The removable storage drive 814 may be a floppy disk drive, magnetic tape drive, optical disk drive, optical storage device, magnetic tape backup device, and / or any other storage device / drive.
[0082] The removable storage drive 814 can interact with the removable storage unit 818. The removable storage unit 818 may include a computer-usable or readable storage device on which computer software (control logic) and / or data are stored. The removable storage unit 818 may be a floppy disk, magnetic tape, optical disc, DVD, optical storage disc, and / or any other computer data storage device. The removable storage drive 814 can read segments from and / or write to the removable storage unit 818.
[0083] Auxiliary storage 810 may include other devices, apparatuses, components, tools, or other methods for allowing computer programs and / or other instructions and / or data to be accessed by computer system 800. Such devices, apparatuses, components, tools, or other methods may include, for example, removable storage unit 822 and interface 820. Examples of removable storage unit 822 and interface 820 may include a program box and box interface (such as those found in video game devices), a removable storage chip (such as EPROM or PROM) and associated slot, a memory stick and USB or other port, a memory card and associated memory card slot, and / or any other removable storage unit and associated interface.
[0084] Computer system 800 may further include a communication or network interface 824. Communication interface 824 enables computer system 800 to communicate and interact with any combination of external devices, external networks, external entities, etc. (individually and collectively referred to by reference numeral 828). For example, communication interface 824 may allow computer system 800 to communicate with external or remote device 828 via communication path 826, which may be wired and / or wireless (or a combination thereof), and may include any combination of LAN, WAN, network, etc. Control logic and / or data may be transmitted to and from computer system 800 via communication path 826.
[0085] The computer system 800 may also be any one and / or an embedded system of a personal digital assistant (PDA), a desktop workstation, a laptop or notebook computer, a netbook, a tablet computer, a smartphone, a smartwatch or other wearable device, a part of the Internet of Things, to name just a few non-limiting examples, or any combination thereof.
[0086] Computer system 800 can be a client or server that accesses or hosts any application and / or data through any delivery paradigm, including but not limited to remote or distributed cloud computing solutions; on-premises or internally deployed software (“internal” cloud-based solutions); “as-a-service” models (e.g., Content as a Service (CaaS), Digital Content as a Service (DCaaS), Software as a Service (SaaS), Managed Software as a Service (MSaaS), Platform as a Service (PaaS), Desktop as a Service (DaaS), Framework as a Service (FaaS), Backend as a Service (BaaS), Mobile Backend as a Service (MBaaS), Infrastructure as a Service (IaaS), etc.); and / or hybrid models that include any combination of the foregoing examples or other services or delivery paradigms.
[0087] Any applicable data structures, file formats, and schemas in the computer system 800 may be derived from standards, including but not limited to JavaScript Object Notation (JSON), Extensible Markup Language (XML), YAML, Extensible Hypertext Markup Language (XHTML), Wireless Markup Language (WML), MessagePack, XML User Interface Language (XUL), or any other functionally similar single or combined representations. Alternatively, proprietary data structures, formats, or schemas may be used individually or in combination with known or open standards.
[0088] In some embodiments, tangible, non-transitory means or articles of art, including tangible, non-transitory computer-usable or readable media on which control logic (software) is stored, may also be referred to herein as computer program products or program storage devices. This includes, but is not limited to, computer system 800, main memory 808, secondary memory 810, and removable storage units 818 and 822, and tangible articles embodying any combination thereof. When executed by one or more data processing means, such control logic can cause such data processing means to operate as described herein.
[0089] Based on the teachings included in this disclosure, those skilled in the art will clearly understand how to use [the method described above]. Figure 8 Embodiments of this disclosure may be made and used with data processing apparatuses, computer systems, and / or computer architectures other than those shown herein. Specifically, embodiments may operate with software, hardware, and / or operating system implementations other than those described herein.
[0090] It should be understood that the Detailed Description section, and not the Summary and Abstract section, is intended to interpret the claims. The Summary and Abstract section may set forth one or more, but not all, exemplary embodiments of the invention as contemplated by the inventors, and therefore is not intended to limit the invention and the appended claims in any way.
[0091] The embodiments of the present invention have been described above using functional building blocks, which illustrate implementations of specified functions and their relationships. For ease of description, the boundaries of these functional building blocks have been arbitrarily defined herein. Alternative boundaries may be defined, provided that the specified functions and their relationships are appropriately defined.
[0092] The foregoing description of specific embodiments so fully reveals the general nature of the invention that others, by applying knowledge of the art, can easily modify and / or adapt various applications of such specific embodiments without excessive experimentation or departure from the general concept of the invention. Therefore, based on the teachings and guidance presented herein, such adaptations and modifications are intended to fall within the meaning and scope of equivalents of the disclosed embodiments. It should be understood that phrases or terms in this specification are for descriptive and not limiting purposes, and that the terminology or phrases in this specification will be interpreted by those skilled in the art based on the teachings and guidance.
[0093] The breadth and scope of this invention should not be limited to any of the exemplary embodiments described above, but should be defined only by the following claims and their equivalents.
Claims
1. A sensor comprising: A housing, the housing comprising at least two first conductive plates; and A printed circuit board (PCB) comprising at least two second conductive plates, wherein the PCB is positioned relative to the housing such that each second conductive plate is aligned with and positioned at a distance from a corresponding first conductive plate to form a set of parallel-plate capacitors. The set of parallel plate capacitors thereon measures at least one of the force or torque along at least two axes of the sensor.
2. The sensor of claim 21, wherein the housing is composed of a material configured to flex in response to an applied force.
3. The sensor according to any one of the preceding claims, wherein the PCB further includes a sensing element configured to measure the capacitance of the parallel plate capacitor during operation of the sensor.
4. The sensor according to any one of the preceding claims, wherein the PCB further includes a protective ring concentric with the second conductive plate.
5. The sensor according to any one of the preceding claims, wherein the PCB further comprises a protective plate located in an internal portion of the PCB and parallel to the second conductive plate.
6. The sensor according to any one of the preceding claims, wherein the set of parallel plate capacitors measures at least one of force and / or torque along at least three axes of the sensor.
7. The sensor according to any one of the preceding claims, wherein the PCB further includes a microcontroller configured to transmit sensor measurement results to a robotic arm via a CAN bus.
8. A robot system comprising: A robotic arm having a proximal end and a distal end; A sensor, the sensor being mounted to the distal end of the robotic arm, wherein the sensor includes a housing containing a first conductive plate and a PCB containing a second conductive plate, wherein the PCB is positioned relative to the housing such that the first conductive plate and the second conductive plate are aligned to form a parallel plate capacitor; and A tool changer, mounted in a manner such that the sensor measures at least one of a force or torque experienced by a tool attached to the distal side of the tool changer. The robotic system is configured to perform at least one of calibration functions or biological processing functions in a biological processing environment.
9. The robot system of claim 8, wherein the proximal end of the robotic arm is mounted to the frame.
10. The robot system of claim 8 or 9, wherein the PCB further includes a protective ring concentric with the second conductive plate.
11. The robot system according to any one of claims 8 to 10, wherein the PCB further comprises a protective plate located in an internal portion of the PCB and parallel to the second conductive plate.
12. The robot system according to any one of claims 8 to 11, wherein the PCB further includes a sensing element configured to measure the capacitance of the parallel plate capacitor during operation of the sensor.
13. The robot system according to any one of claims 8 to 12, wherein the housing further comprises at least two additional first conductive plates, and the PCB further comprises at least two additional second conductive plates aligned with the at least one additional first conductive plate to form a corresponding additional parallel plate capacitor, wherein the parallel plate capacitor and the corresponding additional parallel plate capacitor measure at least one of a force or torque along at least two axes of the sensor.
14. The robot system according to any one of claims 8 to 13, the robot system further comprising a controller coupled to the robotic arm and the sensor, the controller having instructions stored thereon, which, when executed by the controller, cause the controller to control the movement of the robotic arm based on one or more measurements received by the controller from the sensor.
15. The robotic system of claim 14, wherein the controller further includes instructions for attaching a pipette tip to a pipette base based on the one or more measurements.
16. The robotic system of claim 15, wherein the controller further includes instructions for determining the z-position of the pipette tip relative to the bottom of the liquid tray based on the one or more measurements.
17. The robot system of any one of claims 14 to 16, wherein the controller further comprises instructions for positioning one or more edges of the table slot on the platform of the robot system frame and for determining the position of the table slot relative to the frame based on the one or more measurements.
18. A method comprising: A sensor consisting of a set of parallel-plate capacitors is used to measure the applied force or torque; The sensor sends force detection signals to components of the robot system, wherein the force detection signals are based on capacitance changes measured by the sensor; and The state of the robot system is changed based on the force detection signal.
19. The method of claim 18, wherein the change includes turning the electromagnet in the tool changer on or off.
20. The method of claim 18, wherein the change includes moving the robotic arm to a new position.
21. The method of claim 18, wherein the modification includes attaching the pipette to a pipette base.
22. A sensor comprising: A rigid housing configured to deflect when a force is applied, the rigid housing having one or more measuring axes; One or more sets of strain gauges, each set of strain gauges being mounted to the rigid housing and positioned along one or more measuring axes, wherein each set of strain gauges measures the deflection of the rigid housing along one or more measuring axes; and A printed circuit board, at least partially or entirely located within the rigid housing, comprising a first portion and a second portion, wherein analog circuitry is confined in the first portion and digital circuitry is confined in the second portion. Each set of strain gauges is electrically connected to a circuit in the first part of the printed circuit board.
23. The sensor of claim 22, wherein voltage measurements from the one or more sets of strain gauges are converted into force and / or torque measurements.
24. The sensor of claim 22 or 23, wherein the sensor is configured to measure force in the z-direction and torque in the x-direction and y-direction.
25. The sensor according to any one of claims 22 to 24, wherein the rigid housing comprises an outer portion, an inner portion concentric with the outer portion, and a set of three beams connecting the inner portion and the outer portion, wherein the set of one or more strain gauges comprises multiple sets of strain gauges, and each of the three beams has at least one set of strain gauges mounted thereon.
26. The sensor of claim 25, wherein each of the three beams in the set has a first double strain gauge mounted on the top side of the beam and a second double strain gauge mounted on the bottom side of the beam.
27. The sensor of claim 26, wherein the first dual strain gauge and the second dual strain gauge are electrically connected to the printed circuit board via a flexible member, wherein a first end of the flexible member is connected to the printed circuit board and a second end of the flexible member is connected to one of the three beams in the set.
28. The sensor of claim 22, wherein the circuitry on the printed circuit board amplifies the measurement results from the set of one or more strain gauges.
29. The sensor of claim 28, wherein the circuitry includes one or more filters for removing noise from the voltage measurements of the set or sets of strain gauges.
30. The sensor of claim 28, wherein the circuitry includes an analog-to-digital converter, wherein the analog-to-digital converter converts voltage measurements from the set or more strain gauges into binary signals.
31. The sensor of claim 28, wherein the circuitry includes a microcontroller, wherein the microcontroller transmits the sensor measurement results to the robotic arm via a CAN bus.
32. The sensor of claim 28, wherein the circuitry includes a feedback loop, wherein the feedback loop corrects for a baseline voltage difference sensed by a set of strain gauges when there is no load on the sensor.
33. A robot system comprising: Robotic arm, the robotic arm is mounted to the frame ； The sensor according to any one of claims 22 to 32 is mounted to the distal end of the robotic arm; and A tool changer, mounted in a manner that allows the sensor to measure the force and / or torque experienced by a tool attached to the distal side of the tool changer. The robotic system is configured to perform calibration and / or biological processing functions in a biological processing environment.
34. The robot system of claim 33, further comprising a controller coupled to the robotic arm and the sensor, the controller having instructions stored thereon that, when executed by the controller, cause the controller to control the movement of the robotic arm based on one or more measurements received by the controller from the sensor.
35. The robotic system of claim 34, wherein the controller further includes instructions for attaching a pipette tip to a pipette base based on the one or more measurements.
36. The robotic system of claim 34, wherein the controller further includes instructions for determining the z-position of the pipette tip relative to the bottom of the liquid tray based on the one or more measurements.
37. The robot system of claim 34, wherein the controller further includes instructions for positioning the edge of the table slot on the platform of the frame and determining the position of the table slot relative to the frame based on the one or more measurements.
38. A method for modifying the motion of a robotic arm using a contact sensor, the method comprising: Measure one or more sensor values during robotic arm movement in a biological processing environment; Determine when a measured sensor value among the one or more sensor values is greater than a contact detection value, wherein the contact detection value differs from the baseline noise level measured by the contact sensor by at least four standard deviations; Process one or more measured sensor values and send motion commands to the robotic arm based on the measured sensor values.
39. The method of claim 38, wherein an exponential moving average filter is used to smooth the one or more measured sensor values.
40. The method of claim 38, wherein when the measured sensor value exceeds the contact detection value, the motion command instructs the robotic arm to stop moving.
41. A method for assembling a sensor, the method comprising: Connect the first ends of multiple flexible components to a printed circuit board; The printed circuit board is connected to the rigid housing of the sensor; The second ends of the plurality of flexible components are connected to the rigid shell; A set of strain gauges is attached to the rigid housing along each of the plurality of measuring axes. Each set of strain gauges is connected to the second end of the corresponding flexible member among the plurality of flexible members.