SYSTEM OF ROBOTS AND ROBOTIC PARTS INCLUDING METHOD OF CONSTRUCTION AND METHOD OF USE

A robotic component can include a Flexible Circuit Board (FCB) that can be bent into various shapes throughout the robotic component. The FCB can include various integrated sensors that can be manufactured as part of the FCB in a way that reduces the size and number of connections. The FCB can include capacitive force sensors that can measure a quantity of force and can be unitary with the FCB and can be manufactured by folding two electrodes around a compressible dielectric pad.

FIELD OF THE INVENTION

This application relates to the design and construction of robotic parts, and more particularly, improvements in functionality and improvements in compact designs for robotic parts.

BACKGROUND OF THE INVENTION

Humans have been trying to create robots for decades, but with only limited success. Robotic parts such as arms, wrists, and hands suffer from a number of drawbacks and limitations. One of the drawbacks in the field of robotics currently is a limitation on the ability to reduce the size of various features.

As an example, small jointed parts like fingers need to carry numerous sensors, such as pressure sensors joint position sensors, etc. And, in addition to the sensor itself, each sensor has various wires, wiring harnesses, connectors, etc. that must be carried through the fingers, including tight places like knuckle joints. As used herein, the term “wire” can refer to single strands or multiple-strand wires that are insulated with insulating material surrounding the conductive strand(s). The insulating material around the strand is flexible, and the strand with the insulation around it can be bent into various paths throughout an electronic device. However, the strand plus the insulating material around it that form a wire can become bulky when multiple wires are used in the same device or routed along the same path. The terms “wiring harness” can refer to physical connectors that allows two insulated wires to be connectively joined to form a single electric conductor through the use of Newtonian force, including connectors that can connect multiple sets of insulated wires at the same time. Wire harnesses are typically made of insulated metal wires that must be attached to connectors on both sides. The wire harness can then be plugged into corresponding connectors on two circuits, connecting them electrically. This requires that both wires have a connector or harness. These harnesses or connectors can be clips mounted at the end of the conductive strands so that a user can forcefully engage two clips or other connectors together to form a conductive strand that conducts electricity and electric signals through the clip from one strand to the other, thereby forming a single conductive path. To join two wires into a single conductive path, a wiring harness must be applied to both wires, which can be a costly and difficult step in manufacturing as the insulation must be stripped from the end of the wire, the wire must be connected to the harness, etc. For each connection end the electrical insulation must be stripped, then the wire is crimped into pins, then the pins must be inserted into the plastic male connector. This must be done for every end of every wire.

These connections where the end of the wire is connected to a wiring harness create a weak point along the electrical path, and as the wire is flexed back and forth repeatedly in normal usage, the wire is most likely to break at the connection with the wiring harness that allows the two wires to be joined. The places where the wires connect to the harnesses tend to see the most stress, and the wires tend to fail at the places where they are connected to the harnesses. Furthermore, after the two harnesses are linked together, they take up a large amount of space inside the device. When this is multiplied by a large number of wires, the result is either a large number of bulky wires and wiring harnesses that must take up space, or a smaller number of larger multi-wire harnesses that take up more space.

A highly functional robot finger would ideally be able to sense pressure at the tip of the finger, the back of the finger, both sides of the finger, and of course, the inner finger pad where the finger makes contact with an object being gripped by the robot's hand. However, this requires a multitude of bulky sensors, wires, wiring harnesses, and circuit connectors, that must all be packed into a small finger, while also allowing the finger to bend and move. This means that parts such as fingers must be at least a minimum size that is often larger that desired for various applications. Furthermore, as the manufacturer attempts to reduce the overall size of the finger to the minimum size capable of carrying all of the necessary components, the space inside the finger gets more and more crowded, and therefore more and more difficult for the manufacturer to assemble all of the components inside of the tight space. All of this contributes to ever increasing costs as manufacturers attempts to reduce the size of various parts given the constraints of current technology.

In some cases, in order to reduce the size of the fingers, it has been necessary to reduce the number of sensors, the quality of sensors, and/or the types of sensors. This means that there is often a direct correlation between decreasing size of parts such as fingers and decreasing functionality. Manufacturers may also reduce the quality or strength of other parts such as fingers and wrists in order to allow for decreased size, but this decreases in quality, such as decreasing the robustness of hinges and hinged parts, results in inferior products that break easily.

In some cases, the size has been reduced by attempting to remove some components such as sensors from tight parts such as fingers. This can be reducing the number of pressure sensors, but can also mean attempting to measure certain variables such as fingertip position from alternate locations outside of the fingertip. For example, some manufacturers have attempted to measure finger position by placing magnets in the finger tips, and then sensing the proximity of the magnet to other parts such as a palm of a robotic hand. Moving the sensing activity to the palm means there is more space for these sensors. However, this also results in a significant reduction in quality. Placing magnets in the fingertips can have an effect on the robot's ability to grasp and release magnetic objects, but even worse, grasping and releasing magnetic objects will interfere with the sensor's ability to accurately know where the fingertips are positioned. Furthermore, although ample space may exist in a palm area, magnets in the fingertips take up valuable space used for pressure sensors and may interfere with the remaining pressure sensors.

Other manufacturers have attempted to measure position by monitoring the positions of servos in the arm that control the fingers through tendons. However, this can be extremely unreliable. The tendons that connect to the finger tips can stretch over time, resulting in inaccurate readings, and as the tendons pass through the narrow and crowded finger knuckles, even slight interactions with other components such as wires and wire harnesses can lead to inaccurate results. As wires and wiring harnesses interfere with the path of the tendons, the length of tendon does not exactly correlate to finger position. In the state of the current technology, measuring the position of the fingers by monitoring the rotational position of the servos in the arm that drive the fingers is the best option, given that the measuring can occur outside of the finger and reduce the size constraints of a finger, but this method of measuring finger position is prone to inaccuracy.

Various other means also exist for more accurately measuring the rotational position of the joints, and therefore the position of the fingertip, or wrist, or arm, etc. However, to date, either these means produce inaccurate results or have not been reduced in size sufficiently to allow their use in a robotic finger knuckle that can be the size of a human finger while also allowing for tendons wires, and wiring harnesses to exist in the same space.

Up to now, there has been a trade off between various aspects, including the quality of sensing, the number of sensors and the amount of sensed data, the size of the finished parts, and the cost to assemble. For example, as size decreases, the quality of components such as sensors and/or the number of sensors decreases and/or the cost of assembly increases. Furthermore, there are hard limits on the ability to reduce size while still maintaining even a minimum level of sensing at any cost. The same can be said about improving the quality and/or number of sensors, which then increases size and cost, and the same can be said about reducing cost which then results in reduced sensing and increased size. Similarly, the quality of parts such as fingers and wrists can be part of the trade-off, and reducing the robustness of components such as hinges and knuckles can allow for reduced size, but with a corresponding reduction in quality. Improving one of these aspects seems to come at the cost of the others.

It would be desirable to have new robotic technology and new components that allow robotic parts such as fingers, wrists, arms, etc. to be reduced in size to the size of human fingers, wrists, arms, etc, or smaller, while also maintaining robust pressure sensing and position sensing, reducing costs, and maintaining strong parts and components. It would be further desirable if the new robotic technology and new parts result in reduced cost of components and reduced cost of assembly while also allowing for reduced size at the same time.

SUMMARY OF THE INVENTION

This invention overcomes disadvantages of the prior art by providing a system and method for manufacturing robotic parts, including parts that can be analogous to fingers, hands and arms. The system and methods described herein include various ways to reduce the cost of manufacturing, reduce the size of manufactured parts, and increase the reliability and quality of sensed data. These improvements include producing capacitive pressure sensors that are simple in construction and can be manufactured by folding a sheet of material over itself to form a sandwich around a double-sided adhesive. These force sensors are simple and cheap to manufacture, and can be connected to cheap touch sensor chips. The sheet of material can also be a Flexible Circuit Board (FCB) that can connect the sensor to other electronic components, including touch sensor chips and processors. The touch sensor chips can be Integrated Chips (IC) that can be integrated on the FCB, and the IC(s) can be located near the force sensors on the FCB. The FCB can also include multiple sensors on the same FCB, so that, for example, multiple sensors in a finger such as finger tip, sides of the finger, back of the finger, etc, can all be manufactured as part of the same FCB, and can all be connected to the touch sensor chip(s) integrated on the FCB. With all of the sensors and circuits manufactured as a single FCB, the finger can be constructed with no wiring harnesses or other bulky connectors to be connected during manufacturing or taking up space inside narrow parts like a finger. The single FCB can then be arranged through a finger, including through narrow joints such as knuckles, and can be tied into place within a finger, held in place with clips, etc, and can connect sensors to a processor with very little space requirements, leaving space within a small finger for further components. Because the FCB is free from insulation, there is no rubber or other insulation within the fingers to get caught up on moving parts or prevent tendons from sliding freely. The flex circuit connectors can be printed in the same process required to make the circuit board. The connectors can be electrical traces as any other on the FCB, with exposed and plated pads on the end, using the same process used to make the pads of most components on the circuit board. The flex circuit can then be directly inserted into the female connector on the palm. The connector can also be thinner because the flex circuit is thinner than wire connectors.

Additionally, sensors such as rotational position sensors, also referred to as rotational encoders, can be configured to be integrated with the FCB, thereby eliminating the need for additional wires, wire harnesses, and other connectors. These rotational position sensors can be used to measure the rotational position of hinged joints such as finger knuckles. These sensors can utilize the Hall effect to measure the orientation of a diametrically magnetized magnet that can be assembled in a stack with the axis of the magnet on the same axis as the knuckles or other hinges. This approach with stacking a disc shaped magnet and rotational position encoder on axis with the knuckle hinge allows for a small and flat rotational sensor that takes up little space while still reporting rotational position with accuracy. The rotational sensor can also be configured to integrate with the FCB to provide measured data to the processor without the need for additional wiring. The space savings that result from the innovative design of this sensor combined with the space savings that result from the FCB replacing traditional connection types allows for the use of on-axis hall sensors which are significantly more accurate than prior art position sensors for robotic parts.

The use of this precise on-axis rotational position sensor also allows for the use of a 4-bar linkage system for torque sensing. The 4-bar linkage torque sensing system can allow a processor to calculate the pressure being applied to a held object by a finger. A processor can measure minute divergence, or flexing, of finger components by measuring and comparing the rotational position at multiple joints at the same time. As applied pressure increases, so too does the flex in certain components, which can be determined by measuring the rotational positions of multiple joints at the same time. The applied pressure can be determined from the amount of flex. Calculating the applied pressure when a fingertip is in contact with an object means that a pressure sensor such as a capacitive pressure sensor does not need to be used at the fingertip, thereby further reducing the space requirements in the finger while also decreasing production cost.

In an embodiment, a robotic component can include a FCB that can include at least one capacitive force sensor, the capacitive force sensor being unitary with the FCB, and the capacitive force sensor having two electrodes folded around a compressible dielectric pad, and at least one rotational position encoder, the rotational position encoder being on the FCB as an Integrated Chip (IC), and at least one magnet, the at least one magnet being embedded in a joint of the robotic component so that the at least one magnet and the at least one rotational position encoder are on-axis with the joint, so that the rotational position encoder can determine the rotational position of the magnet within the joint.

The FCB can include at least one strain relief loop that passes around a loop holder within the robotic component. The FCB can include at least one bending segment, the bending segment allowing the FCB to be folded into multiple planes. The at least one rotational position encoder can include at least two rotational position encoders, and wherein the FCB can be bent so that a first rotational position encoder is in a first plane and measures a rotational position around a first axis, and a second rotational position encoder is in a second plane and measures a rotational position around a second axis, wherein the first axis and the second axis are in different planes. The FCB can include at least one knot segment, wherein the knot segment is tied in a knot around a support within the robotic component. The joint of the robotic component can have a hollow central canal that passes through the center of the joint, including passing through the rotational axis of the joint, and wherein the FCB passes through the hollow central canal and the rotational axis of the joint. The robotic component can also include a layer of foil between the at least one capacitive sensor and the outside of the robotic component, the layer of foil shielding the capacitive sensors from external capacitance. The robotic component can include a 4-bar linkage system, wherein a motor that powers the movement of one joint will also power the movement of a second joint through the 4-bar linkage, and wherein a linkage bar can be semi-rigid, so that a quantity of force applied to a finger tip can be calculated from the rotational position of the two joints when the linkage bar is flexed under force. The FCB can be tied in a knot around the linkage bar. The joint of the robotic component can have a hollow central canal that passes through the center of the joint, including passing through the rotational axis of the joint, and wherein tendons that control the movement of the robotic component are routed through the hollow central canal and the rotational axis of the joint. The robotic component can have multiple FCBs in different portions of the robotic component, and the multiple FCBs can be connected together by FPC connectors and can be connected free of soldering or wiring harnesses. The FCB can include holes through the FCB and wherein tendons that control the movement of the robotic component can be routed through the holes through the FCB.

DETAILED DESCRIPTION

There are a great many possible implementations of the invention, too many to describe herein. Some possible implementations that are presently preferred are described below. It cannot be emphasized too strongly, however, that these are descriptions of implementations of the invention, and not descriptions of the invention, which is not limited to the detailed implementations described in this section but is described in broader terms in the claims.

As used herein, the term robotic finger refers to a robotic part that can include force sensors, joints, joint position sensors, and flexible circuit boards (FCBs). Although the robotic finger described herein is similar in appearance and function to a human finger, the technology described herein is not intended to be limited to human forms. Similarly, as used herein, the terms robotic hand, palm, and wrist refer to robotic parts that include force sensors, joints, position sensors, and FCBs, and although the robotic parts described herein are similar in appearance and function to the human body, the technology described herein is not intended to be limited to human forms.

FIG.1is a perspective view of a robotic finger, according to an illustrative embodiment. A robotic finger100can have a base108, and multiple phalange segments including distal phalange102, middle phalange104, and proximal phalange106. Phalanges102and104can be separated by joint or knuckle112, and phalanges104and106can be separated by joint or knuckle114. Knuckles112and114can bend or curl inward along arrow A and arrow B, respectively. Phalange106and base108can be separated by joint116that can bend or curl along arrow C, and phalange106and base108can also be separated by joint118that can bend or yaw along arrow D. Joints116and118allow phalange106to move relative to base108along two different axis. It should be clear that in various embodiments, larger or smaller numbers of phalanges are possible, with joints between each phalange, and it should be clear that any two phalanges can have one or more than one joint between them thereby allowing for one or more than one axis of movement between any two phalanges.

The design described herein allows for the finger, including joints, to have a very small form factor. In various embodiments, the finger, including joints, can have a maximum width FW of 16 mm or less. In various embodiments, the finger can have a maximum height FH of 18 mm or less. In various embodiments, a finger knuckle can have a maximum knuckle height KH of 20 mm. The reduced size is possible in part due to the absence of wiring and wiring harnesses throughout the finger, along with the compact design for the knuckle rotational position sensors. The finger can be fully functional with capacitive force sensors in four directions, knuckle rotational position sensors, and a torque force sensor, all within the compact design having a maximum finger width of 16 mm, a maximum finger height of 18 mm, and a maximum knuckle height of 20 mm.

In traditional designs, pressure sensors in a finger would require a separate sensor unit for each touch sensitive area, and each pressure sensor unit would have wires extending from the sensor so that each of the sensors can be connected to a controller. In some cases this could include bulky wiring harnesses or connectors. The design described herein has a number of pressure sensitive areas without the need for wires or wiring connectors. The finger100shown inFIG.1can have four pressure sensors that can sense pressure at pressure sensitive areas122,124,126, and128, however, different numbers and configurations of pressure sensors are possible.

FIG.2Ais an upper perspective view of circuitry, including sensors, from inside the robotic finger ofFIG.1, according to an illustrative embodiment, andFIG.2Bis a lower perspective view of the circuitry ofFIG.2Aalso showing the position of knuckle magnets, according to an illustrative embodiment. Finger circuitry200can include a finger FCB202, finger tip force sensors222,224,226, and228, and rotational position encoders212,214,216, and218. As used herein, the terms “rotational position encoder,” “rotational encoder,” and “contactless potentiometer” can be used interchangeably. Finger tip sensor226can sense force on the back of the finger, in a location associated with a fingernail in a corresponding human finger, and finger tip sensor224can sense pressure on the distal tip of a finger tip. Finger tip sensor222can sense pressure on a first side of the finger, and finger tip sensor228can sense pressure on a second side of the finger, opposite from the first side. Although this description describes specific sensors in specific locations, and describes them in the context of similarity to human fingers and human sensing locations, it should be clear that this is merely illustrative, and various numbers and arrangements of sensors are possible.

Rotational position encoder212can sense the rotational position of the diametrically magnetized magnet embedded in the knuckle112, and can therefore detect the rotational position of the knuckle112. or put another way, can detect the angle of the joint between distal phalange102and middle phalange104. Rotational position encoder214can sense the rotational position of knuckle114between phalanges104and106. Rotational position encoder216can sense the rotational position of knuckle116between phalange106and base108as phalange106curls inward toward the palm, and rotational position encoder218can sense the rotational position of joint118as phalange106moves in a yaw direction relative to base108. A diametrically magnetized magnet, such as diametrically magnetized disc magnet232,234,236, and238can be positioned in each joint, and the encoder can detect the rotational position of the magnet. As used herein, the term “diametrically magnetized magnet” refers to a magnet that is magnetized across the diameter, with the poles located on the curved surfaces along the outer circumference of the magnet. The magnets shown inFIG.2Bare shown in proximity to the corresponding rotational encoders, however, it should be clear that the magnets are fixed within the joints and move with the joints relative to the encoders, so that the encoders can detect the rotational position of the magnets, and thereby detect the rotational position of the joints.

Taken together, the rotational position encoder and diametrically magnetized magnet form a rotational position sensor. The rotational position encoder can be an integrated chip (IC) on the FCB that can calculate and digitize the angle. The rotational position encoder can include 4 analog hall effect sensors arranged on the IC of the FCB in a circle around the axis center. The chip can interpolate the analog signals and perform basic trigonometric math right there on the IC. The output of the IC that is the rotational position encoder can be a digital angle, and that digital angle data can be transmitted through traces on the FCB.

The rotational position encoders and the force sensors can be integrated as part of the FCB. Integrating sensors such as sensors222,224,226, and228, rotational encoders212,214,216, and218as part of the FCB allows for a design that is free from insulated wires and wiring harnesses. The FCB can include separate conductive traces for each sensor, including force sensors and rotational position sensors, and can connect each sensor to circuits and processors located outside of the finger without the need for additional connectors or wires within the finger. By having all of the sensors connected to circuits and processors outside of the finger through fine traces on a single FCB, the physical volume of all connections from sensors in the finger to connections outside of the finger is substantially reduced, allowing for much smaller form factor fingers, while also allowing for reduced assembly cost because all rotational encoders and force sensors in a finger can be already pre-manufactured together in a single finger circuit unit200.

The FCB202can be routed through narrow spaces in an articulated finger, including though the narrow spaces inside a joint or knuckle. However, as different joints move and move in different directions, different forces can be exerted on the FCB in different directions. To overcome this problem, a series of strain relief loops can be folded into the FCB, such as strain relief loops244,246, and248. These strain relief loops provide extra slack in the FCB, so that the overall length can lengthen and shorten as necessary, without the FCB getting tangled or getting in the way of other components. The loops can be wrapped around loop-holders (not shown) throughout the path of the FCB, including within the finger or other components, explained more fully below.

Additionally, the FCB can be tied in place, such as FCB knot242. FCB knot242can be tied around a structural component (not shown) within the finger or other component, and can secure the FCB in place within the finger while the various finger components move in different directions and exert various forces on the FCB. In various embodiments, the knot242can be tied around a linkage bar within the finger, explained more fully below. Because the FCB itself is flexible and can be physically tied into a knot, it can be secured in place in a way that allows flexible motion of the finger and the FCB without the need for bulky attachment devices or circuit routing components.

FIG.3is a top view of the circuitry ofFIG.2A, shown in a flat conformation before the force sensors are folded and before the FCB is arranged into the shape used inside the finger ofFIG.1, according to an illustrative embodiment. Turning now toFIGS.1,2A,2B, and3, strain on the FCB can further be reduced by having at least a portion of the FCB be split along the length, so that the FCB can more easily be flexed in different directions without bowing, binding, or kinking. Having a split252in an FCB202can be particularly valuable in places where multiple joints between the same segments allow for bending along different directions, or through three dimensions. By way of non-limiting example, the split252can allow a first side254to move and flex independent of second side256. When proximal segment106moves along arrow C and along arrow D relative to base108, the two narrower sides can move independently more freely and more flexibly compared to a single FCB having the combined width of254plus256.

The FCB can be designed to fold into nearly any shape. As shown inFIG.3, there can be one or more 90-degree turns such as 90 degree turn282before the FCB turns into two strands254and256that pass through the knuckles116and118. Combined with a 90-degree bend at bending zone284, the FCB path can route along the sidewall of the middle segment, then turn and route along a different direction through the knuckles116and118. Similarly, 90 degree turn286and a 90 degree bend at bending zone288allow the FCB to exist in one plane in one place in the finger, and turn to route along another plane 90 degrees away. When the FCB is bending at a bending zone or flexing through a knuckle, it is flexing along a direction in and out of the page as shown inFIG.3, or put another way, the very thin dimension is bending around a curve, while the wider dimension does not need to bend. The 90 degree turns help to allow the FCB to be folded in such away that the flat dimension bends through knuckles112and114, while segment276the FCB can be offset 90 degrees and routed vertically though the side of the middle segment. Similarly, knot section350can have angles352and354that allow the FCB to be bent and tied, and then continue to route through the next knuckle with the flat dimension oriented to bend around the axis of rotation of the knuckle. Tabs362and364can help to secure the knot together when it is tied around the flex rod.

The same FCB is shown inFIG.3in a flat conformation after manufacturing of the FCB, and shown inFIGS.2A and2Bin the folded conformation as it is found inside the finger ofFIG.1. Each pressure sensor, such as pressure sensor222, is a capacitive force sensor that includes two electrodes:312and322. Electrodes312and322are unitary parts of the single circuit unit200. Distal electrode322can be folded over at hinge332so that distal electrode322can be nearly in contact with proximal electrode312. Electrodes312and322can be held nearly together, while also being held just slightly apart, in the folded conformation with a compressible dielectric pad262, such as double sided adhesive or double sided tape, to form an adjustable capacitor. The compressible dielectric pad262should be elastically compressible, should be an insulating dielectric material, and can have a thickness that can be between 0.2 mm and 2 mm. The compressible dielectric pad262can have adhesive on both sides, such as a double sided tape, and as used herein, the dielectric pad can be referred to as a compressible dielectric double sided tape, or double sided adhesive. However, although having adhesive on both sides increases the convenience of manufacturing, it should be clear that adhesive can be applied separately, and the pad does not need to be a double-sided tape. However, as used herein, in the interest of a clear description, the compressible dielectric pad may also be referred to as a dielectric double-sided tape, or compressible dielectric double-sided adhesive.

Traces in the FCB can connect the sensor to a capacitance-to-digital converter chip, also referred to herein as a touch sensor chip, such as Integrated Chip (IC)270so that changes in capacitance can be measured as the tape gets squished and the two electrodes on each side312,322come closer together. When a compressive force is applied to the capacitive force sensor212, the distance between electrodes312and322decreases, which changes the capacitance. By measuring the capacitance, we can measure the pressing force using an IC270that can be on the same circuit board connected to the electrodes. In various embodiments, the touch sensor IC270can be centrally located at a hub between pressure sensors. In various embodiments, the touch sensor IC can be positioned within a central cavity of a finger tip, as shown inFIG.2B, so that it is close to the force sensors and in a location where space is at less of a premium.

Similarly, sensor224can be made by folding electrode324over electrode314at hinge334and using compressible dielectric adhesive264. Sensors226and228can also be made by folding the electrodes around a compressible dielectric adhesive such as a double sided tape. In various embodiments, multiple capacitive force sensors, such as sensors222,224,226, and228can be connected to the same IC270, and the sensors can be arranged around the fingertip to measure forces from multiple sides.

This arrangement creates a compact design that can measure a quantity of force being applied from multiple different directions. It can also be assembled quickly and at little cost by folding the electrodes over the double sided tape to form sensors that are part of the unitary circuit unit200. This requires nothing more than a piece of sticky tape and folding the circuit. The sensor can be created by folding a single flexible circuit board, which eliminates the need for multiple circuit boards sandwiched together and connected by wires. Furthermore, there is no need to create one of the electrodes by other means such as coating a surface with an electrically conductive layer that can be difficult to manufacture. Multiple sensors can be folded from the same flexible circuit board, thereby creating a 3D sensing array. The sensors are also integrated with the rest of the circuit. Because the electrodes are folded from the same flexible circuit board that contains the integrated chips, the electrical connections can be printed directly onto the circuit. This further reduces the cost of the materials, the cost of manufacturing, and the size of the unitary circuit unit200. The unitary circuit unit can be a component within a finger while taking up very little space within the finger and thereby allowing for additional functional components within the finger, such as rotational position sensors within the joints. The folded sensor can be an elegant and compact design that is free of unnecessary parts that take up space or unnecessary assembly steps. A sensor can be made of two electrodes that are unitary with the FCB and folded over a compressible dielectric pad, free from additional components or connections.

FIG.4Ais a side view of the circuitry ofFIG.2, showing pressure sensors folded into the sensing conformation and showing area of detail4B and cross section line4C-4C, according to an illustrative embodiment.FIG.4Ashows fingernail force sensor226, fingertip force sensor224, and first side force sensor222. Rotational position encoders212,214,216, and218are also shown. The circuit unit200is shown inFIG.4Aas it is found in a finger when it is fully installed within the finger. A Flexible Printed Circuit Board connector (FPC connector)204is used to connect the FCB202of the finger to the circuits of the palm, explained more fully below. The FPC connector204can be printed in the same process required to make the circuit board. The connectors204can be electrical traces as any other on the FCB, with exposed and plated pads on the end, using the same process used to make the pads of most components on the circuit board. The flex circuit can then be directly inserted into the female connector on the palm. The FCB of a finger can be connected to the FCB of the palm using the FPC connector204, so that the fingers can be connected to the palm without additional wiring or soldering. The FPC connector can also be thinner because the flex circuit is thinner than wire connectors. The FCB can have a section of extra length404, and the extra length section404can make assembly quicker and easier as it provides slack in the system between the finger and the palm. The extra length section allows slack in the system so that the connector204can be connected to the palm FCB1002easily. The extra length section404can also provide additional slack as the finger moves relative to the palm.

Strain relief loops246and244are shown in position as they are wrapped around a loop-holder (not shown) within the finger, and knot242is shown as it would be tied around a component within the finger, such as a linkage bar, (not shown) to hold the FCB in place while the finger is moving and bending. The loop holders and knot holder are described in more detail in later figures. Circuit unit200, including FCB202, is shown in the folded conformation as it would be threaded through the finger, including through the finger joints, with rotational encoders in the correct locations at joints, and force sensors in the correct locations within the finger, although the rest of the finger is not shown inFIG.4A.

FIG.4Bis a detailed view of the pressure sensors shown in detail area4B ofFIG.4A, according to an illustrative embodiment. Force sensor226includes electrodes316and326that are folded at hinge336, and double sided dielectric adhesive266holding the electrodes near each other but slightly separated. As pressure is applied to electrode316, the double sided dielectric adhesive266is slightly compressed, which results in a change in capacitance that can be measured by IC270and converted to a digital signal that can be transmitted through the FCB202to a processor that can be outside of the finger.

FIG.4Cis a cross sectional view of the sensors shown inFIG.4A, taken along cross section line4C-4C ofFIG.4A, according to an illustrative embodiment. The pressure sensors222,224,226, and228can be connected through the FCB202to the IC270, and IC270can be nestled within the finger tip cavity where space is less important and where the touch sensor IC270can be located close to the pressure sensors.

The sensor arrangement can be shielded with a conductive foil, such as aluminum foil, to shield the sensors from the external capacitance that can occur when bringing the sensor close to a conductive surface, such as a human finger or other conductive surface. Eliminating external capacitance allows for measuring the force acting on the sensors without having stray capacitance from electrically conductive surfaces nearby decrease the accuracy of the force measurements. The result is a very accurate sensor array that is also compact and low cost. In various embodiments, the sensors can be finalized with a protective cover made of a flexible plastic material. The protective cover for a finger can be a flexible or semi-flexible material around a conductive foil, while other force sensors in the palm of the hand can have a protective hard plastic cover, explained more fully below. In various embodiments, sensors can be covered with a hard plastic shell.

FIG.5Ais a bottom perspective view of a finger, according to an illustrative embodiment. andFIG.5Dis a bottom perspective view of various components inside of the finger ofFIG.5A, including structural components, and showing the placements of magnets for rotational sensors, according to an illustrative embodiment.FIG.5Ashows the finger100with a plastic covering over the fingertip, protecting the force sensors. Finger100can have a knuckle112between distal phalange102and middle phalange104, and knuckle112can have an axis of rotation A. Similarly, knuckle114between middle phalange104and proximal phalange106can have an axis of rotation B, and knuckle116. In various embodiments, there can be two joints between proximal phalange106and base108, and curling joint116can have axis of rotation C. and yaw joint118can have axis of rotation D. In various embodiments, axis of rotation C and axis of rotation D can be 90 degrees from each other. In various embodiments, a universal joint can be used for knuckle116and joint118, and axis of rotation C and axis of rotation D can be arranged in the same plane. Various arrangements of joints and axis are possible.

FIG.5Bis a side view of the finger ofFIG.5A, shown without the outer shell, according to an illustrative embodiment, andFIG.5Cis a cross section of the finger ofFIG.5B, taken along cross section line5C-5C, and viewed from below, according to an illustrative embodiment. One or more of the phalanges can have multiple structural frame components inside a phalange. Distal phalange102can have a right frame502and a left frame512. Terms like “left” and “right” are used herein to describe various components of a finger as a way to make the descriptions clear and easy to understand, however, it should be clear that features described as left can be on the right, and visa versa. Right frame502and left frame512can come together to form a distal bone522. Structural components inside the finger can be referred to herein as bones, although it should be clear that the bones and joints in the finger100are not to be confused with the bones and joints of human anatomy, and can differ in number, shape, and arrangement from the bones of human anatomy.

The pressure sensors of the finger can be arranged around the exterior of the distal bone522, so that the inner electrodes312,314,316,318are held against the distal bone522. When an object presses against the outer electrode322,324,326, or328, the force compresses the dielectric double sided adhesive material262,264,266, or268within the sensor, resulting in a change in capacitance. The FCB can pass through the hollow inside of the distal bone522on the way to the middle bone524.

Middle phalange104can have a right frame504and a left frame514, and the right frame504and left frame514can come together to form a middle bone524. Proximal phalange106can have a right frame506and a left frame516, and the right frame and the left frame can come together to form a proximal bone526. Base108can have an upper frame508and a lower frame518, and the upper frame and the lower frame can come together to form a base bone528. Terms like “upper” and “lower” are used herein to describe various components of a finger as a way to make the descriptions clear and easy to understand, however, it should be clear that features described as upper can be on the lower, and visa versa. An auxiliary bone527can be positioned between joint116and118. This auxiliary bone227connects the joint116and joint118, and together, the joint116, auxiliary bone527, and joint118allow the base108and proximal phalange106to move in multiple degrees of freedom relative to each other. Various bones can have hollow portions or hollow channels that can contain components of joints, magnets, sensors, FCB, and/or other components. A left frame and a right frame (or an upper frame and a lower frame) can be joined together to form a bone with various components held in place within the bone.

FIG.5Dis a bottom perspective view of various components inside of the finger ofFIG.5A, including structural components, and showing the placements of magnets for rotational sensors, according to an illustrative embodiment. Diametrically magnetized magnet232,234,236, and238can be on-axis for each joint. The central axis of the disc-shaped magnet can be the same axis as the pivoting axis for the joint. As shown on magnet238, this means that the N and S poles of the magnet can be on the flat surface of the magnet, with the Non one side and the S on the other side of the axis D. The specific rotation of the N and S around the axis can vary from that shown inFIG.5D, however, the N and S can both be on the face and on opposite sides of the axis so that a diameter line connecting the N and the S passes through the central axis D. Each of the joints112,114,116, and118can have a diametrically magnetized magnet arranged on-axis in the same way.

A finger100can have a linkage bar530that can link between bones. Linkage bar510can be anchored to the distal bone502at pivot532, and linkage bar510can be anchored to proximal bone506at pivot536. Distal bone522, linkage bar530, middle bone524, and proximal bone526together can form a four-bar linkage, explained more fully below. Middle bone524can have a bar cavity534that can accommodate the linkage bar in different positions and orientations as the finger bends and straightens.

FIG.5Eis a detailed view of the area of detail5E inFIG.5C, showing an arrangement of joint components within the bone, according to an illustrative embodiment. Turning now toFIGS.5A,5B,5C,5D, and5E, the arrangement of a magnet, a rotational encoder, and the rotational axis of a joint are described. Joint114can have bearings544that facilitate the movement between middle bone524and proximal bone526, and magnet234can be on-axis with the bearing and joint. Magnet234can secured to the middle bone524, and the rotational position encoder214can be next to the magnet234, but secured to the proximal bone526. When the middle phalange104pivots relative to proximal phalange106around joint114, the magnet234secured to the middle bone524pivots relative to the rotational encoder214secured to the proximal bone526. As the magnet rotates relative to the rotational encoder, the N and S poles of the magnet rotate relative to the encoder, the encoder can sense the rotation of the magnet as the N and S poles travel around the axis. An air gap556can separate the magnet and sensor chip of the rotational encoder allowing them to rotate freely relative to each other without contacting each other. In various embodiments, the air gap556can be approximately 0.5 mm.

As shown inFIGS.5C and5E, the rotational encoder chip214is mounted to the right proximal frame516, and the magnet is mounted to the right middle frame514, however, it should be clear that in various embodiments, the rotational encoder chip could be mounted to the left proximal frame526with the magnet on the left middle frame524, and in various embodiments, the magnet could be on a proximal frame with the encoder on a middle frame. The arrangement of the magnet on one phalange with the encoder on the other phalange allows the encoder to detect the rotational position of the magnet, and thereby detect the rotational position of one phalange relative to the other. The specific arrangement between phalanges and between sides could be varied while still sensing the rotational position of one phalange relative to the other.

Each joint can have a similar arrangement of bearings, magnet, encoder, and air gap. Joint112can have bearings542that can be press fit into the frame allowing for free rotation between distal bone522and middle bone524. Magnet232can be on axis along axis A with encoder212positioned near magnet232with an air gap552between the encoder and magnet that can be approximately 0.5 mm. As the distal bone and the middle bone move relative to each other around joint212, the magnet rotates relative to the rotational encoder, and the rotational encoder can sense the changing position of the N and S poles. The sensed data of the magnet rotating relative to the encoder can then be used to determine the rotational position of the joint, and thereby the rotational position of the distal phalange relative to the middle phalange.

Similarly, joint116can have bearings546, a magnet236that can be on-axis along axis C, and a rotational encoder216that can be positioned near the magnet236with an air gap556between the magnet and sensor that can be approximately 0.5 mm. Joint118can have bearings that can be on axis along axis D, and a rotational encoder218that can be positioned near the magnet238with an air gap between the magnet and encoder that can be approximately 0.5 mm. The sensed data of the magnet rotating relative to the encoder can then be used to determine the rotational position of the joint. The stack including the reference magnet, the air gap, the rotational encoder, and the FCB can be 9 mm or less, resulting in a highly accurate sensor for measuring the position of the joint while also taking up very little space inside the knuckle and allowing for other components such as tendons to pass through the knuckle without interference.

In various embodiments, the rotational position sensors can be rotational potentiometers instead of contactless potentiometers. A rotational potentiometer can be free of magnets, and can include a shaft instead of a diametrically magnetized magnet. The rotational potentiometer can be an IC on the FCB, similar to the rotational encoders shown inFIG.5D. The shaft can be press-fit into one side of a joint, such as a middle bone, and the rotational potentiometer can be mounted the other joint component, such as a proximal bone. The two parts of the joint that rotate relative to each other could then be connected by the shaft of the rotational potentiometer. However, this design that replaces the contactless potentiometer with a rotational potentiometer is superior to the potentiometer, at least because the potentiometer uses internal conductive brushes in an arrangement with friction that results in wear over time and eventual breakdown with repeated usage, while the magnet-based design has no friction and no wear, and because the potentiometer is susceptible to water while the IC of the contactless pentiometer can be sealed for a water resistant design. Accordingly, this novel design has implemented the use of a Hall effect magnet rotational position sensor that results in superior performance, superior lifespan, superior reliability, superior accuracy, and a superior compact design.

The innovative design described herein allows for a significant reduction in the space requirements of various components. By having a single FCB202that carries all signals through the finger in a compact arrangement, additional space is available to have rotational position sensors actually located on axis within each joint. And the compact design of the rotational position sensors allows enough space for the FCB to pass through the interiors of joints. Allowing the FCB to pass through the interior of a joint means the FCB is flexed less and requires less available slack along the FCB. Inferior prior art designs have been forced to route wires along the outside of a joint in a way that requires significant extra slack and results in significant wear on the wires.

In an embodiment, space requirements can be further minimized by having the rotational encoders214and216mounted along the inside of the proximal frame, with the FCB202routed along the edge and folded into the middle of the proximal bone. The FCB can be folded into the shape shown inFIGS.2A and2B, with the encoders along the edge of the interior of the finger. The FCB can have a proximal segment276, as shown inFIG.2A, that can be pressed along the side of the proximal frame, and the FCB can be folded through three dimensions in space so that the FCB can pass through the middle of each joint and flex as the joints move. The FCB202can be tied in a knot242around the linkage bar530so that the FCB remains in position arranged down the centers of joints112and114. The split252in the FCB allows the FCB to flex more easily as it passes down the centers of joints116and118, and as the joints116and118rotate along different axis and the phalanges move in multiple different directions relative to each other.

A multifunctional clip564can hold encoder214in place on the proximal bone526, while also providing a loop-holder to hold strain relief loop244.FIG.6Ais an exploded bottom perspective view of various components inside the finger ofFIG.5A, including multipurpose clips that can maintain the positions of rotational encoders and the FCB; according to an illustrative embodiment, andFIG.6Bis a side view of various components inside the finger ofFIG.5A, showing rotational encoders held in place by the clips and showing the arrangement of the FCB and magnets; according to an illustrative embodiment. InFIG.6A, the multifunctional clip564is shown isolated in position564A before assembly, and is shown in assembled position564B where it can hold the rotational position encoder214in place. Turning toFIGS.5C,5E,6A, and6B, the multifunctional clip564can hold encoder214and multifunctional clip566can hold encoder216in place on the proximal frame. Together, clips564and566secure the proximal segment276in place along the proximal frame. The clips hold the FCB in place while also securing the encoder precisely on the axis of rotation. The clips also contribute to keeping the sensor and the magnet slightly separated by an air gap, which allows for improved operation of the rotational position sensor.

Strain relief loop244is wrapped around loop holder604of clip654, and strain relief loop246is wrapped around loop holder606of clip566. Loop holders604and606can work together to support the FCB202in place down the middle of the finger. Strain relief loops244and246can also be seen inFIG.4A. Having the FCB wrapped around the loop holders with strain relief loops not only keeps the FCB in place, but the strain relief loops can provide slack when necessary and hold excess slack out of the way when necessary as the finger bends and straightens. Similarly, clip562helps to secure a rotational encoder precisely on axis for joint112, and the FCB holder602of clip562helps to route the FCB202in place down the middle of the finger.

Rotational position encoders212and214can work together to sense force on the surface570of distal phalange102, as indicated inFIG.5A. Capacitive force sensors can sense contact force on pressure sensitive areas122,124,126, and128, however, the bottom surface of the finger, shown as570inFIG.5A, may not need a capacitive force sensor. A four-bar linkage system within the finger can work with the rotational position encoders212and214to sense force on surface570. Capacitive force sensors can be shielded by a thin layer of aluminum foil. As shown inFIG.6B, the foil610can shield each of the sensors. The protective outer cover of the fingertip can then be applied over and around the foil.

FIG.7Ais a schematic diagram of a 4-bar linkage system that can use magnetic rotational sensors to determine torque and pressure, shown with the finger in a straight conformation, according to an illustrative embodiment. In this schematic diagram, distal segment702is joined to middle segment704at joint712, and middle segment704is joined to proximal segment706and joint714. Distal segment702also has a pivot722that is connected to linkage bar720, and linkage bar720is connected to proximal segment706at pivot726. Distal segment702, middle segment704, and proximal segment706can be rigid. Linkage bar720can be made from a semi-rigid material, so that linkage bar720will flex under force. Joint714can be an active joint driven by a motor such as a servo located within the palm or arm of a robot that can be connected to the joint with tendons, explained more fully below. When the motor forces the joint714to rotate, or put another way, when the motor forces the middle segment704to move around the joint714relative to the proximal segment706, the linkage bar between pivot726and pivot722will pull the distal segment702to move around the joint712relative to the middle segment.

FIG.7Bis a schematic diagram of the 4-bar linkage system ofFIG.7A, shown with the finger in a bent conformation and without applied pressure, according to an illustrative embodiment. After the motor has forced the joint714to rotate, or put another way, after the motor has forced the middle segment704to move around the joint714relative to the proximal segment706, the linkage bar726between pivot726and pivot722has now pulled the distal segment to move around joint712relative to the middle segment. The four-bar linkage system causes both joints to rotate, or causes all three segments to move around the joints, while only one of the joints is directly powered. This four-bar linkage system allows the finger to curl around multiple joints without the need to provide a motor to power movement at each joint. The angle of the passive joint712can be computed from the angle of the driven joint714and the lengths of the segments.

FIG.7Cis a schematic diagram of the 4-bar linkage system ofFIG.7B, shown with pressure applied to an outer, fingernail side of a finger, thereby flexing the linkage bar in a shortened conformation; according to an illustrative embodiment. When force is applied to the top, fingernail portion of the distal segment702, such as in the direction of arrow T, the semi-rigid linkage bar720can compress or otherwise flex to allow the distal segment702to rotate around the passive joint712under the pressure in the direction of arrow U. The system can then calculate the torque applied to the fingernail area by measuring the rotational angle of joint712and the rotational angle of joint714and comparing them to the no-load condition shown inFIG.7B.

FIG.7Dis a schematic diagram of the 4-bar linkage system ofFIG.7B, shown with pressure applied to an inner side of a finger, thereby flexing the flex bar in an elongated conformation; according to an illustrative embodiment. When force is applied to the bottom of the finger, such as in the direction of arrow V, the semi-rigid linkage bar720can stretch or otherwise flex to allow the distal segment702to rotate around the passive joint712under the pressure in the direction of arrow W. The system can then calculate the torque applied to the bottom of the finger by measuring the rotational angle of joint712and the rotational angle of joint714and comparing them to the no-load condition shown inFIG.7B.

FIG.8Ais a perspective view of the interior of the robotic finger ofFIG.8Ashowing the components of the 4-bar linkage system, according to an illustrative embodiment,FIG.8Bis a top view of the partial robotic finger shown inFIG.8A, according to an illustrative embodiment, andFIG.8Cis a cross section view of the partial robotic finger ofFIG.8B, taken along cross section line8C-8C, according to an illustrative embodiment. Distal bone522can be distal segment802of the four-bar linkage system, middle bone524can be middle segment804of the four bar linkage system, and proximal bone526can be proximal segment806of the four bar linkage system. Distal segment802is connected to middle segment804at joint112, and proximal segment806is connected to middle segment804at joint114. Linkage bar530can link between proximal segment806and distal segment802. Linkage bar530can be anchored to proximal segment806at pivot536, and anchored to distal segment802at pivot532. Middle bone524can have a bar cavity534that can accommodate the semi-rigid linkage bar530in different positions and orientations as the finger bends and straightens.

This arrangement creates a four-bar linkage system with a known relationship between the two rotational joints112and114. In various embodiments, the linkage bar530can have an S-curve, or other shape, along the length of the bar that allows it to flex in either direction as force is applied to the top or bottom of the finger. By measuring the rotational position of joint112and joint114, the system can calculate force being applied to the distal segment that causes the linkage bar530to flex one way or the other.

FIG.8Dis a cross section view of the partial robotic finger ofFIG.8B, taken along cross section line8C-8C showing the finger in a bent conformation, according to an illustrative embodiment. Turning toFIGS.8C and8D, flexor tendon822can pull on the middle segment804to cause the middle segment804to rotate around the joint114into a bent conformation, as shown inFIG.8D. Extensor tendon824can pull on the middle segment804to cause the middle segment804to rotate around the joint114into a straight conformation, as shown inFIG.8C. When the flexor tendon822powers segments804and806into a bent conformation around joint114, the linkage bar530pulls segment802into a bent conformation around joint112, as shown inFIG.8D. When the extensor tendon824powers the segments804and806into a straight conformation around joint114, the linkage bar530pulls segment802into a straight conformation around joint112, as shown inFIG.8C. The two tendons822and824can pass through the center of joint116as a tendon bundle820. However, it should be clear that the tendons are not required to be bundled together as a tendon bundle820to pass through the finger, the palm, or the wrist. Because of the various innovative and space saving designs described herein, more space is available inside the fingers, palm, and wrist than is required for the various components.

FIG.9is a perspective view of an assembled robotic hand, including a wrist, palm, and fingers, according to an illustrative embodiment. Robotic hand900can have a plurality of fingers100that can be attached to a palm910. Tendons and FCBs from each finger can pass through the palm and through the wrist920to connect to various circuits, processors, servos, etc. of a robot. In various embodiments, a robotic hand can have five fingers, more than five fingers, or less than five fingers. As used herein, the word “palm” refers to the portion of a hand that does not include fingers. The word “palm” is not intended to refer to a particular side of the hand.

FIG.10is a perspective view of the circuitry, including sensors, from inside the robotic hand with fingers, according to an illustrative embodiment. Palm circuitry1000can include a palm FCB1002, palm force sensors1022,1024,1026, and1028, finger rotational position encoders1012and1014, and wrist rotational position encoders1016and1018. Palm circuitry1000can include one or more FPC connectors1004that allow finger circuitry units200to be connected to the palm circuitry unit1000.

Each finger circuit unit200can be plugged into an FPC1004on the palm. The FCB of the palm can have traces that correspond to the traces of the finger FCBs202. All of the electrical signals originating from within a finger, such as sensed data from force sensors and/or rotational position sensors of a finger, can be transmitted through the FCB of the finger, and then transmitted to the FCB of the palm. The signals from more than one finger can then be transmitted through the FCB of the palm back to the arm. In this way, there is no need for bulky wires or a large number of wiring connections within the palm. Each finger can be connected to the palm FPC1004, and then all sensed information can be transmitted to the arm through the palm FCB, thereby substantially reducing the space requirements within the palm.

FIG.11Ais a perspective view of the palm circuitry, including sensors, from inside of a robotic palm shown without fingers, according to an illustrative embodiment, andFIG.11Bis a top view of the circuitry ofFIG.11A, shown in a flat conformation before the sensors are folded and before the FCB is arranged into the shaped used inside the palm ofFIG.9, according to an illustrative embodiment. Palm circuitry1002can be manufactured flat as a single sheet to reduce costs, and then it can be folded into the appropriate conformation.

Palm circuitry1002can include two force sensors1022and1024that are arranged on the top of the palm portion to sense contact force on the back of the hand, and two force sensors1026and1028that are arranged on the bottom of the palm portion to sense contact force on the bottom, or inside of the hand. These palm force sensors can be constructed in the same way as the force sensors in the fingers. As shown inFIGS.11A and11B, capacitive force sensor1022can include electrode1112and electrode1122. Electrode1112and electrode1122can be folded at hinge1132, and the two electrodes can be brought together and stuck together using a dielectric double sided adhesive1162. The descriptions of the manufacturing and functionality of the capacitive force sensors of the fingers, described above, also describes the manufacturing and functionality of these capacitive force sensors in the palm. Sensors1022,1024,1026, and1028can be manufactured flat and folded together with dielectric double-sided adhesive separating the two electrodes. Sensor1024includes electrodes1114and1124separated by hinge section1134, and dielectric double sided adhesive1164. Sensor1026includes electrodes1116and1126separated by hinge section1136, and dielectric double sided adhesive1166. Sensor1028includes electrodes1118and1128separated by hinge section1138, and dielectric double-sided adhesive.

Rotational position encoders1016and1018can work with diametrically magnetized magnets to sense the rotational position of the wrist in two directions including an up-down direction and a side-to-side, or yaw, direction. The outer fingers, which can be referred to as a pinkie and a thumb, can have an additional joint, described more fully below, that allows the base of the finger to pivot relative to the rest of the palm. Rotational position encoder1012can work with a diametrically magnetized magnet to sense the rotational position of the base joint for the pinkie. Rotational position encoder1014can work with a diametrically magnetized magnet to sense the rotational position of the base joint for the thumb. The descriptions of the manufacturing and functionality of the rotational position sensors of the finger joints, described above, also describes the manufacturing and functionality of these rotational position sensors in the palm.

In various embodiments, the palm FCB1002and/or finger FCB can include ancillary circuitry such as ancillary circuitry1172and1174. In various embodiments, ancillary circuitry1172and or1174can be multiplexing ICs that can help to connect the multiple sensors to a single data line. This can reduce the number of traces required on the FCB, and can therefore reduce the size of the FCB as it passes through various space-limited components such as the wrist. In various embodiments, there can be a processor and an Inertial Measurement Unit (IMU). Space savings from various features herein, including integrated sensors, allow for placement of additional components such as processor units, multiplexing ICs, inertial measurement units, temperature sensors, etc. on the FCB and within the hand. Ancillary circuitry1172and/or1174can be various multiplexing ICs, processors, IMUs, and/or various other ancillary circuitry.

As shown inFIG.11B, pinkie circuit1142and thumb circuit1144of the palm FCB1002can be manufactured in the same way as each other, with the circuits manufactured as components of a symmetric FCB1002. The FCB pinkie circuit1142and thumb circuit1144can be folded into different conformations, so that the thumb circuit can be positioned further back along the side of the palm. This allows for an opposable thumb to be positioned back from the other fingers while also allowing the circuitry to be easily manufactured symmetrically. This symmetrical manufacturing eliminates the need for separate FCBs to be produced for left hands vs right hands, which further reduces manufacturing costs.

The FCB1002can be folded in a way that includes strain relief loops1152and1154that can allow the FCB to flex and move as the hand moves relative to the wrist. Folding sections1151and1153can be folded to create strain relief loops1152and1154, respectively. The FCB can also be folded in a way that includes folded sections1056and1058at the bottom, near the fingers. These folded loops1056and1058can allow the FCB to elongate during assembly, including during attachment of the fingers, and then allow the FCB to be tucked into a compact design after assembly. Folding sections1155and1157can be folded to create folded loops1156and1158, respectively.

The FCB1002can be manufactured with a tendon hole1176for the tendons of each hand. The tendons, which can be arranged as a tendon bundle, can pass through the tendon hole1176and can connect with servo motors in the arm. By having a hole for the tendons to pass through the FCB, the FCB and the tendons can occupy the same areas of the hand without interfering with each other.

FIG.12Ais an exploded perspective view of the top of a partially assembled palm, showing circuits, sensors, and removed back cover, according to an illustrative embodiment. The circuitry unit1002of the palm can be joined with a rigid plastic palm bone1202. In various embodiments, the palm bone can include multiple frame components that can be assembled with the circuitry unit1002, and/or the circuitry unit1002can be folded into the folded conformation ofFIG.11Awith the palm bone. Capacitive force sensors can be arranged on the exterior of the palm bone. In various embodiments, the sensors can be finalized with a protective cover made of a flexible plastic material. In various embodiments, sensors can be covered with a hard plastic shell that can be suspended on pegs above the sensors. These pegs can increase the distance to the external contact surface, thereby minimizing external capacitance and minimizing interference with the measurement of force that is measured by measuring the capacitance between the two electrodes.

A rigid or semi-rigid top cover1204can snap into engagement with the palm bone1202. The top cover1204can have pegs1222and1224that can align with the sensors on the top of the hand1022and1024. In a fully assembled position, the pegs1222and1224can rest against the top sensors1022and1024. The top sensors can thereby be sandwiched between the pegs of the top cover and the palm bone. When an object is pressed against the top cover1204, the forces are transmitted through the pegs to the sensors on the top of the hand, and the sensors1022and1024are thereby squeezed between the pegs and the palm bone. As the capacitive force sensors1022and1024are squeezed, the capacitance between the two electrodes changes, and the quantity of force can be determined from the change in capacitance.

FIG.12Bis an exploded perspective view of a partially assembled palm, showing circuits, sensors, and removed hand bottom cover, according to an illustrative embodiment. Similar to the top of the palm shown inFIG.12A, the bottom of the palm has force sensors1026and1028that can be on the surface of the palm bone1202. A rigid or semi rigid bottom cover1206can snap into engagement with the palm bone1202. The bottom cover can have sensor engagement points1226and1228that can align with the sensors1026and1028on the bottom of the hand. The bottom sensors can thereby be sandwiched between the palm bone and the bottom cover1206. When an object is pressed against the bottom cover1206, the forces are transmitted through the bottom cover to the sensors on the bottom of the hand, and the sensors1026and1028are thereby squeezed between the bottom cover and the palm bone. As the capacitive force sensors1026and1028are squeezed, the capacitance between the two electrodes changes, and the quantity of force can be determined from the change in capacitance. The capacitive force sensors in the palm operate under the same principles as the capacitive force sensors in the fingers, and similarly, they occupy very little space, are manufactured as a single component with the FCB, are very cheap to manufacture, and do not require additional wires or connections inside the hand.

As shown inFIGS.12A and12B, the symmetrical circuitry unit1202can be folded with the pinkie in a first conformation and the thumb folded in a second conformation, resulting in an asymmetrical hand with an opposable thumb.FIG.13Ais a partially assembled view of a hand, showing thumb and pinkie joints and thumb and pinkie joint rotational position sensors, according to an illustrative embodiment. Thumb1302is positioned further back on the hand, closer to the wrist1400. In addition to the various finger joints described above, thumb1302and pinkie1304have an additional joint that allows them to pivot inward in a direction that is into the page, when looking atFIG.13A. That is to say, pinkie1304and thumb1302can be bent inward towards the bottom of the hand in a direction that allows the opposable thumb to help to grip objects in conjunction with other fingers. The pinkie1304can also pivot inwards towards the bottom of the hand in a direction that allows the pinkie1304to help grip objects in conjunction with other fingers. A pair of bevel gears can be used to translate the movement of tendons to the inward pivoting of the pinkie and thumb.

FIG.13Bis a detailed view of a pinkie joint1320ofFIG.13A, showing an arrangement of bevel gears, according to an illustrative embodiment. The top bevel gear1340can have a tendon track1342that accommodates a tendon that can connect to a servo in the arm. Top bevel gear1340also has gear teeth1344that engage with gear teeth1354in the bottom bevel gear1350. As the tendon rotates the top bevel gear, the movement of the tendon is translated to the bottom bevel gear, which then causes the base108of the pinkie1320to rotate around axis E. A hollow canal1356can extend through the joint1320, and the hollow canal can allow the FCB and tendons of the finger to pass through the center of the joint. Similar to other joints, the hollow center of the joint allows the FCB to pass through the joint with minimal bending of the FCB as the finger is moving. The pinkie joint1320can be aligned behind the ring finger1308and directly in line with the ring finger1308, so that the FCB and tendons of the ring finger can pass through the center of the pinkie joint1320. The thumb joint1310can have similar construction, with a hollow canal, and can be aligned behind the index finger1306and directly in line with the index finger1306, so that the FCB and tendons of the index finger can pass through the center of the thumb joint1310.

A diametrically magnetized magnet1360can be embedded inside the top bevel gear1340, and acts as a reference for the rotational encoder within the joint1320.FIG.13Cis a detailed view of the pinkie joint ofFIG.13B, showing a rotational position sensor within the joint, according to an illustrative embodiment. Rotational position encoder1012can detect the rotational position of magnet1360within top bevel gear1340. As the top bevel gear turns, and thereby turns the lower bevel gear and causes the pinkie base108to rotate around axis E, the rotational position encoder1012can detect the rotational movement of the diametrically magnetized reference magnet within the top bevel gear. In this way, the rotational position encoder1012is able to detect the rotational position of the joint1320while still allowing the center of the joint to remain hollow. Similarly, the thumb1302has a thumb joint1310that operates under the same principles, including a pair of bevel gears, and a rotational position encoder that detects the rotational position of a reference magnet embedded within a bevel gear.

14A is a perspective view of the wrist ofFIG.9, showing the hollow central channel that can accommodate tendons and FCBs, according to an illustrative embodiment. Wrist1400can use a universal joint1412that can allow for side-to-side yaw movement around axis F, and up-and-down movement around axis G. A hollow central canal1402allows various tendons and FCB from the hand to pass through the center of the wrist, including passing through axis F and axis G. Allowing the FCB to pass through the center of the wrist reduces the strain on the FCB as the various joints are moving. An outer support structure1404can hold all of the various components within the wrist in place.

FIG.14Bis a perspective view of selected components within the palm ofFIG.12Band the wrist ofFIG.14A, showing bevel gear components, according to an illustrative embodiment. The universal joint1412can have a right side bevel gear1422, a top bevel gear1424, and a left bevel bear1426. As used herein, the labels left, top, and right are used for clarity and simplicity of explanation, and are not intended to refer to any absolute direction. The right side bevel gear1422can have a tendon track1428and tendon attachment points1430. Tendons can be routed around the track and connect between the attachment points1430and servos, so that the servo in a different location, such as the arm, can rotate the right side bevel gear1422. Similarly, the left side bevel gear1426can have a tendon track and tendon attachment points, so that the left side bevel gear can also be powered by a servo in a different location, such as the arm. Tendons can pass through the central canal1402to connect to servos that can be located in the arm.

When both the left side bevel gear and the right side bevel gear are rotated in the same direction around axis G, the wrist rotates in that direction around axis G. When the left side bevel gear is rotated in a first direction around axis G, and the right side bevel gear is rotated in the opposite direction around axis G, the wrist rotates around axis F. The loops folded into the FCB at the wrist allow the wrist to bend in different directions without pulling on or causing strain on the FCB.

FIG.14Cis an exploded view of the left bevel gear and outer structure of the wrist ofFIG.14B, showing a rotational position sensor; according to an illustrative embodiment. Turning toFIGS.14A,14B, and14C, the bevel gear1426can include a clip1446that holds the rotational position encoder1018in place on axis G. An insert1448can help to hold the rotational position encoder1018in the clip1446. Diametrically magnetized magnet1450can be mounted in the side arms1406so that the rotational position encoder1018can sense the rotational position of the magnet1450, and therefore sense the rotational position of the bevel gear1426. The rotational position encoder1018and magnet1450form a rotational position sensor1452that is on axis with axis G.

Wrist1400can have two rotational position sensors located within any two of the three bevel gears. By sensing the rotational position of any two out of the three bevel gears, the processor can determine the rotational position of the universal joint around both the F axis and the G axis. In various embodiments, rotational position encoder1016and rotational position encoder1018can be on the left and right, or the left and top, or the top and right bevel gears. A rotational position sensor located within the top bevel gear can be on axis with axis F.

The flexible printed circuit can be made with standard manufacturing processes including automatic IC assembly. The circuit parts can then cut from the production sheet and folded around the palm structure, including passing through a hole in the structure in order to place sensors on both sides of the palm. The hall effect, on-axis, position encoders on the joint axis can detect the position of the radially polarized magnets embedded in the actuated segments. In order to achieve this positioning, slots are designed in the structural pieces which hold the circuit in its proper position. The finger circuits can be similarly folded and assembled together with the structural segments of the fingers. For the fingers plastic clips can affix the circuit in their corresponding slots. Because the finger bends at multiple joints, strain relief loops included in the circuit design can help to accommodate the bending. Starting from the fingertip the circuit can assembled in its slot and a plastic clip can fix it in place. The fingertip halves can be brought together and the force sensors can be folded to cover the outside of the fingertip. The fingertip can then be covered in aluminum foil to shield the force sensors from detecting proximity and then covered by a flexible plastic skin. The circuit can be knotted around the linkage bar to keep it securely in position during finger movements. The circuit can be routed very close to the joint axis thus minimizing bending, and the circuit can include a strain relief loop to release strain on the FCB. The circuit can be placed in the slot in the proximal segment and clipped in place. The final section of the fingertip circuit can be bent around to form the relief loop for the knuckle. The circuit can pass straight through the middle of the knuckle minimizing bending during finger movement. Additionally this circuit strip that passes through the knuckle can be split into two to further increase bending allowance, especially needed because the knuckle allows movement in 2 orthogonal axes. The end of the finger circuit strip can include a printed connector to the palm circuit. In order to accommodate assembly the end can be longer then required and will be folded up after connecting and attaching the finger to the palm. This can create a very compact sensor circuit made of few modular pieces that cover the multitude of moving segments in the robot hand with sensors. This eliminates the need to attach additional wires as the circuits themselves are the wires and the connectors. The on-axis position encoders provide very accurate position feedback which is also robust to external magnetic fields because of the proximity of the reference magnet to the detecting IC. Because of the accurate position feedback and on-axis encoders on each joint this allows us to measure torque in the fingertip using a 4 linkage mechanism.

FIG.15Ais a method of manufacturing a robotic finger, according to an illustrative embodiment. At box1502, the finger circuitry can be printed and the IC components and connectors can be placed and soldered onto the FCB. All soldering can be performed at the PCB manufacturing facility. No additional soldering is required for the rest of the manufacturing process, and circuits can be clipped directly into position during manufacturing of the finger. At box1504, a compressible dielectric pad can be applied to an electrode of a capacitive force sensor of the FCB, and the two unitary electrodes of the capacitive force sensor can be folded together around the compressible dielectric pad to form a capacitive force sensor that is a unitary part of the FCB. At box1506, attach the tendons to the structural pieces for the finger so that they can pull and cause the structural pieces to move. At box1508, fold the circuit roughly into shape. Bend the circuit to form the strain relief loops that lead to the fingertip and knuckle. At box1510, the knot segment can be pre-folded so that it can create a tight loop around the flex rod. At box1512, tie the circuit using a simple knot around the flex rod that connects to the fingertip mechanism. Secure the knot with the tabs on the FCB. At box1514, fold the fingertip part of the circuit and insert it into the side of the fingertip with space for the rotational position sensor. At box1516, slide the circuit into the fingertip ensuring both the rotational encoder and the force sensor on the same side go into their corresponding positions. At box1518, fix the circuit in place with the clip for the fingertip rotational encoder. At box1520, add the bearing to the other side of the fingertip structure. At box1522, reference magnets for the rotational encoders can be press fit, or otherwise attached to the joints. This can include pressing two reference magnets into the middle segment to be reference magnets for the rotational position encoders for the distal and middle joints. At box1524, pass the circuit through the middle segment. At box1526, the middle segment can be inserted into the side of the fingertip with the bearing, and slide the fingertip over the circuit. At box1528, insert the flex rod for the 4-bar linkage and torque sensor, and ensure the FCB is properly routed through the inside of the finger tip and joints. At box1530, hold the sensors in place, and wrap the aluminum foil shield around the sensors. Tape can be used to hold the foil in place. At box1532, cover the fingertip with the flexible plastic skin. The skin should cover the foil, hold the sensors tightly around the finger bone, and hold the fingertip halves together. At this point, the fingertip is complete, and the circuitry with the rotational position sensors for the middle segment can be dangling from the fingertip. At box1534, insert the circuit into the proximal segment with space for the rotational position encoders, and fix the rotational position sensors in place with the clips. The circuit can now be sticking out of the proximal segment from two ends, and the ends can have 90 degree turns in the circuit to align the circuit with the knuckle and middle segment channels. At box1536, form the strain relief loop between the fingertip and the proximal segment. At box1538, bring the fingertip and middle segment assembly over the proximal segment, checking that the relief loop sits freely in the middle of the proximal segment. At box1540, connect the flex rod to the proximal segment. At box1542, press fit, or otherwise attach the reference magnets into the knuckle segment for the proximal joints for axes C and D. At box1544, the double stranded segment of the FCB can be routed through the canal through the knuckle segment. At box1546, form a strain relief loop between the proximal segment and the knuckle segment, also called the base, by bending the circuit while holding the base and the proximal segment. At box1548, align the knuckle with the proximal segment, ensuring that the circuit loops are in the correct position and free to move freely down the middle of the proximal segment. At box1550, pass the tendons that drive the fingertip though the knuckle canal alongside the circuit. The tendons and FCB can be routed through the centers of the knuckle joints and through the axes C and D. The tendons can pass between the two circuit strands when both the circuit and tendons are in the correct positions. At box1552, insert bearings into the other side of the proximal segment. At box1554, with all the pieces aligned and the circuit folded into the correct shape, press the other side of the proximal segment over the assembly. The 4-bar linkage fingertip mechanism is now complete. The fingertip, middle segment, and proximal segment rotate together when the tendon is pulled to rotate the fingertip. One of the two knuckle joints, also referred to as one of the two joints between the base and the proximal segment, is now complete, and the finger can move up and down. At box1556, slide the flexible skin over the proximal segment, thereby holding both halves together. Fold the middle segment skin over the middle segment. The fingertip is now complete. The other joint of the knuckle (the yaw joint), will be completed when the finger is assembled into the palm, explained below. At this point, the FCB can be sticking out of the knuckle and is ready to be connected to the palm circuit using an FPC connector. The tendon that drives the fingertip can also be sticking out of the knuckle segment, and the tendons that drive the knuckle joints (yaw and pitch motions) can be dangling outside and around the knuckle segment.

FIG.15Bis a method of manufacturing a robotic hand, according to an illustrative embodiment. At box1558, the palm circuitry can be printed and the IC components and connectors can be placed and soldered onto the FCB. All soldering can be performed at the PCB manufacturing facility. No additional soldering is required for the rest of the manufacturing process, and circuits can be clipped directly into position during manufacturing. At box1560, a compressible dielectric pad can be stuck to an electrode of a capacitive force sensor, and the two electrodes of the capacitive force sensor can be folded together around the compressible dielectric pad to form a capacitive force sensor. At box1562, the FCB can be bent approximately into the shape it will be in within the palm. At box1564, insert the palm FCB into the palm structure or palm bone. At box1566, align the rotational position encoders into the correct position on the palm structure. At box1568, align the capacitive force sensors into the correct position on the palm structure. At box1570, route the pinkie circuit and thumb circuit along the sides of the palm and insert into the bottom structure of the pinkie base and the thumb base. The rotational position encoders can be positioned for the thumb and pinkie bases. At box1572, the front of the palm circuit can pass through a hole in the palm to the bottom side of the palm. Folded loops can allow the FCB to extend during the process of manufacturing and connecting to fingers, and then the FCB can be tucked into a compact design with the loops within the palm structure. At box1574, the three finger connector circuit segments can be arranged on the bottom of the palm structure, and the force sensors can be placed in position on the bottom of the palm structure. At box1576, the rotational position encoders on the FCB can be placed within the bevel gears of the wrist, and the three bevel gears can be enmeshed together. Reference magnets can be placed in the side arms of the wrist, and the side arms can be inserted into the wrist support structure. At box1578, ensure the gimbal structure of the strain relief loops of the FCB and the bevel gears all move freely and independently with respect to the side arms. At box1580, the bearings for the finger bases can be pressed into the palm structure. At box1582, the fingers bases can be inserted into the bearings, and the tendons of the finger can be passed through the tendon holes of the palm structure and palm FCB. The finger circuits can be passed through the channel At box1584, the finger circuits that can be dangling from the bottom of the hand can be connected to the palm connectors that can be dangling from the bottom of the hand. At box1586, the finger circuits can be folded into place with strain relief loops, and the bottom portions of the palm, pinkie, and thumb can be attached and screwed in place. At box1588, attach the tendons to the bevel gears of the wrist. At box1590, align the pegs of the top cover of the palm with the capacitive force sensors on the top of the palm, and attach the top cover of the palm to the palm so that the pegs can press against the capacitive force sensors. At box1592, attach the flexible bottom cover of the palm, making sure the capacitive force sensors are aligned with the corresponding indents. In various embodiments, a sheet of metal foil, such as aluminum foil, can be adhered to the inside of the palm cover to shield the capacitive force sensors from environmental electrical noise. At box1594, connect the circuits of the hand to the processor of the robot. At box1596, connect the tendons from the hand to servo motors within the arm.

FIG.16is a method of sensing force using a capacitive sensor, according to an illustrative embodiment. At box1602, press against a capacitive force sensor with Newtonian force. Pressing against the capacitive force sensor includes pressing a first electrode towards a second electrode and compressing a compressible dielectric pad between the two electrodes. At box1604, compressing the pad causes the two electrodes to become closer to each other which changes the capacitance between the two electrodes. The capacitive signal from the capacitive force sensor changes in response to the change in capacitance. At box1606, process the capacitive signal at an Integrated Chip (IC) into a digital signal. At box1608, transmit the digital signal to a processor. At box1610, using the processor, calculate the force on the capacitive sensor. In various embodiments, calculating the force can include interpolating between calibration points. Calibration points can be obtained by placing a test weight with a known weight on the capacitive sensor and recording the capacitive sensor readout and a calibration point. Multiple weights can be used to create multiple calibration points, and the multiple calibration points can be used by the processor to interpolate between calibration points. In an embodiment, the processor can calculate the force as equal to a scale factor x capacitive reading+calibration offset.

FIG.17is a method of sensing force using rotational position sensors, according to an illustrative embodiment. At box1702, read the rotational position of a first joint. At box1704, read the rotational position of a second joint. At box1706, compute the length of the linkage bar, based on the known rotational positions and the lengths of the rigid segments, with a processor using inverse kinematics. At box1708, compare the actual length of the flexible segment to the length of the flexible segment when it is relaxed in a no-load condition. At box1710, calculate the torque being applied to the finger from the length difference between the flexible segment length now and the flexible segment length under the no-load condition. The torque can be calibrated by hooking known weights from the fingertips.

FIG.18is a schematic view of a robot control processor, according to an illustrative embodiment. The robot control processor1800can be connected to the hand through one or more FCBs that can be routed through the wrist. The robot control processor can have a capacitive force sensor module1802that can determine the quantity of force applied to a capacitive force sensor. A capacitive sensor1832can be connected to the capacitive force sensor module1802of the processor1800. In various embodiments, an optional multiplexer can be connected to multiple capacitive force sensors, so that the connections from multiple capacitive force sensors can pass through the multiplexer and be connected to the capacitive force sensor module1802. The capacitive force sensor module can calculate the quantity of force by interpolating between calibration points.

The robot control processor1800can have a rotational position sensor module1804that can determine the rotational position of a joint. A rotational position encoder can be connected to the rotational position sensor module1804. In various embodiments, an optional multiplexer can be connected to multiple rotational position encoders, so that the connections from multiple rotational position encoders can pass through the multiplexer and be connected to the rotational position sensor module1804. The rotational position sensor module can determine the rotational position of a joint from the rotational data provided by the rotational position encoder.

The robot control processor1800can have a bus1820that can connect various modules with each other. The robot control processor1800can have a torque force sensor control module1806that can determine the force on a fingertip from the rotational position of two joints. The torque force sensor control module1806can receive the rotational position of the two joints from the rotational position sensor module1804, and can use that information to calculate the force on the fingertip.

The robot control processor1800can have a motor control module1810. The motor control module1810can be connected to the various servo motors, and the motor control module1810can instruct various servo motors to move and thereby move the various joints within the hand. The processor can use the rotational position data from the rotational position sensor module1804to determine the rotational position of each joint as the motor control module1810directs the servos to move the joints. The motor control module1810can work together with the rotational position sensor module1804to accurately control the position of the fingers and hand of the robot.

The foregoing has been a detailed description of illustrative embodiments of the invention. Various modifications and additions can be made without departing from the spirit and scope of this invention. Features of each of the various embodiments described above may be combined with features of other described embodiments as appropriate in order to provide a multiplicity of feature combinations in associated new embodiments. Furthermore, while the foregoing describes a number of separate embodiments of the apparatus and method of the present invention, what has been described herein is merely illustrative of the application of the principles of the present invention. For example, in various embodiments, the technologies described herein can be applied to any number of different shapes that do not resemble a human hand, such as various claw shapes, including axially symmetrical claws with fingers or other grippers arranged around an axis. Other shapes and arrangements are also possible. Also, as used herein, various directional and orientational terms (and grammatical variations thereof) such as “vertical”, “horizontal”, “up”, “down”, “bottom”, “top”, “side”, “front”, “rear”, “left”, “right”, “forward”, “rearward”, and the like, are used only as relative conventions and not as absolute orientations with respect to a fixed coordinate system, such as the acting direction of gravity. Additionally, where the term “substantially” or “approximately” is employed with respect to a given measurement, value or characteristic, it refers to a quantity that is within a normal operating range to achieve desired results, but that includes some variability due to inherent inaccuracy and error within the allowed tolerances (e.g. 1-2%) of the system. Note also, as used herein the terms “process” and/or “processor” should be taken broadly to include a variety of electronic hardware and/or software based functions and components. Moreover, a depicted process or processor can be combined with other processes and/or processors or divided into various sub-processes or processors. Such sub-processes and/or sub-processors can be variously combined according to embodiments herein. Likewise, it is expressly contemplated that any function, process and/or processor herein can be implemented using electronic hardware, software consisting of a non-transitory computer-readable medium of program instructions, or a combination of hardware and software. Accordingly, this description is meant to be taken only by way of example, and not to otherwise limit the scope of this invention.