WO2023168465A2 - A robot gripper mechanism - Google Patents

A robot gripper mechanism Download PDF

Info

Publication number
WO2023168465A2
WO2023168465A2 PCT/VN2023/000003 VN2023000003W WO2023168465A2 WO 2023168465 A2 WO2023168465 A2 WO 2023168465A2 VN 2023000003 W VN2023000003 W VN 2023000003W WO 2023168465 A2 WO2023168465 A2 WO 2023168465A2
Authority
WO
WIPO (PCT)
Prior art keywords
gripping
gripping member
gripped
shafts
members
Prior art date
Application number
PCT/VN2023/000003
Other languages
French (fr)
Other versions
WO2023168465A3 (en
Inventor
Dinh Si QUANG
Original Assignee
Dtt Technology Joint Stock Company
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Dtt Technology Joint Stock Company filed Critical Dtt Technology Joint Stock Company
Publication of WO2023168465A2 publication Critical patent/WO2023168465A2/en
Publication of WO2023168465A3 publication Critical patent/WO2023168465A3/en

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
    • B25J—MANIPULATORS; CHAMBERS PROVIDED WITH MANIPULATION DEVICES
    • B25J15/00—Gripping heads and other end effectors
    • B25J15/02—Gripping heads and other end effectors servo-actuated
    • B25J15/0206—Gripping heads and other end effectors servo-actuated comprising articulated grippers
    • B25J15/024—Gripping heads and other end effectors servo-actuated comprising articulated grippers having fingers directly connected to actuator
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
    • B25J—MANIPULATORS; CHAMBERS PROVIDED WITH MANIPULATION DEVICES
    • B25J15/00—Gripping heads and other end effectors
    • B25J15/0033—Gripping heads and other end effectors with gripping surfaces having special shapes
    • B25J15/0042—V-shaped gripping surfaces
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
    • B25J—MANIPULATORS; CHAMBERS PROVIDED WITH MANIPULATION DEVICES
    • B25J15/00—Gripping heads and other end effectors
    • B25J15/04—Gripping heads and other end effectors with provision for the remote detachment or exchange of the head or parts thereof
    • B25J15/0475—Exchangeable fingers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
    • B25J—MANIPULATORS; CHAMBERS PROVIDED WITH MANIPULATION DEVICES
    • B25J15/00—Gripping heads and other end effectors
    • B25J15/08—Gripping heads and other end effectors having finger members
    • B25J15/12—Gripping heads and other end effectors having finger members with flexible finger members

Definitions

  • the present invention relates to a robot gripper mechanism, more specifically to the robot gripper mechanism suitable for use in programmable educational robot cars, which may be collectively referred to as programmable educational robots.
  • mBots are popularly used as STEAM educational robots for beginners, for example, children, to make teaching and learning of robot programming being simpler and more fun.
  • the produced mBots have a simplified structure that allows children of appropriate ages to assemble themselves according to the instructions to form a completed educational robot, and practice programming concepts and techniques for the mBots. This helps children understand robot construction, electronic components, fundamentals of programming, thereby help develop logical thinking and design skills.
  • programmable educational robots typically comprise a robot chassis, battery pack, wheel assemblies , driver block, and sensor block.
  • the robot chassis can be made from frames and/or panels.
  • the battery pack can be mounted in the blank space inside of the robot chassis to reduce an overall size of the robot.
  • the driver block and the sensor block control activities of the robot according to information of the sensor, sensed from the surrounding environment, for example, the driver block controls the robot to follow road markings on which the robot moves or to avoid an obstacle, etc., based on obtained identification information of the road markings or the obstacle from the sensor block, for example.
  • the wheel assemblies are powered by the battery pack and are driven to generate a suitable torque on the wheels from which the robot moves.
  • Li-po Lithium polymer
  • Batteries of a voltage of about 3.7V are commonly used for small-sized programmable educational robots, while that of a voltage of about 6V are commonly used for largesized programmable educational robots.
  • This is attributed to the fact that in order to increase the output voltage of the battery, it is necessary to increase the size of the battery significantly, which requires a significantly large blank space inside of the robot chassis to arrange the battery pack therein; in other words, the robot chassis of a significantly larger size is required.
  • programmable educational robots need to be aimed at compactness to facilitate transportation, assembly, control operation, and reducing production costs.
  • Programmable educational robots can help beginners approach programming, for example, children who learn and practice programming techniques based on Scratch software, which can help them either quickly learn how to code, or become capable doing advanced programming using PC, for example.
  • programmable educational robots can completely be applied to do more complex tasks for learning and entertainment due to their potential, for example, they can be programmed to participate in a competitive game, wherein they, for example, may need to accelerate, push objects to a predetermined position, move on uneven surfaces, etc.
  • programmable educational robots which is difficult for them to increase the supplied power from the battery to the step motor; in other words, it is difficult to increase the torque of the step motor in certain times, for example, when acceleration or increasing load of the motor is required, because it is required to increase the size of the battery pack so as to have an increase of the battery voltage and the overall size of the robot thus may not be feasible or desirable.
  • gripper mechanisms to grip, lift, and move objects from one location to another location, for example, ones for gripping, grabbing, holding objects, or the like.
  • some commercially available gripper mechanisms typically use a servomotor to rotate two jaw-tips horizontally.
  • the two jaw-tips are mounted on a gripper holder, but still need to be rotate freely relative to the holder by a certain angle.
  • the mechanisms therefore require pivot parts, or if bolts and nuts are used only, they need to be tightened just enough, so that the bolts and nuts still hold the jaw-tips, but not so tight that prevent the jaw-tips from rotating.
  • the assembly and usage are complicated because the bolts and nuts are only tightened enough.
  • the bolts and nuts tend to loosen gradually, they are thus required to regularly re-tightened, causing inconvenience in use.
  • gripper mechanisms have been described in the patents and patent applications, such as CN208342875U, CN213081498U, CN108582137A, CN106826881 A, or CN214352514U, which generally use two gripping members (jaws) with jaw-tips to grip and grasp an object to be gripped/grasped by adjusting a distance between the two gripping members so that the jaw-tips grip both sides of the object to be gripped/grasped.
  • the two gripping members are linked together through linked bars or gears so that they can be rotated relative to each other.
  • the distance between the gripping jaw-tips will be varied so as to grip the object to be picked up or release the object to be picked up.
  • the jaw-tips always need to remain a gripping force for tightly applying the object, and in order to maintain such a gripping force, the servomotor needs to be driven for continuous operation (constant power consumption) to produce a required torque to press the gripping jaw-tips against the object.
  • An object of the present invention is to provide a gripper mechanism for a robot, which can overcome one or more of the above-mentioned problems.
  • Another object of the present invention is to provide a robot gripper mechanism, which is simple in structure, compact, easy to assemble, easy to use, reduces power consumption, and is capable of secure, long-term stable operation.
  • Yet another object of the present invention is to provide a robot gripper mechanism, which is suitable to use for programmable educational robots, using a DC- DC boost converter circuit to increase the battery voltage supplied to the drive motor, thereby preventing a significant increase in the overall size of the robot in increasing the battery voltage.
  • the present invention provides a robot gripper mechanism comprising: a first gripping member and a second gripping member are made of elastic material, in which the first and second gripping members have first and second gripping surfaces, respectively, for gripping both sides of an object to be gripped, by contacting and pressing the first and second gripping surfaces against the both sides of the object to be gripped; a first gripping member shaft for mounting the first gripping member and a second gripping member shaft for mounting the second gripping member; a mounting bracket for mounting and rotationally supporting the first and second gripping member shafts thereon; a gripping member shaft driving assembly to rationally drive the first and second gripping member shafts around axes along with axial directions of the first and second gripping member shafts respectively; in which: the first gripping member shaft and the second gripping member shaft are arranged basically parallel to each other and kept in a fixed position during operation; the first and second gripping members are arranged to protrude from the first and second gripping member shafts respectively, with
  • the gripping member shaft driving assembly comprises a first gripping electric motor to drive the first gripping member shaft and a second gripping electric motor to drive the second gripping member shaft.
  • the mounting bracket comprises a mounting plate for mounting the first and second gripping electric motors, and the motor shafts (or axes) of the first and second gripping electric motors serve as the first and second gripping member shafts.
  • first and second gripping members are mounted on the first and second gripping member shafts using first and second mounting bars, respectively, wherein, the first and second gripping members are constructed with mounting slots for inserting the first and second mounting bars, respectively, the first and second mounting bars are constructed with mounting holes for inserting the motor shafts of the first and second gripping electric motors, respectively.
  • the first and second gripping electric motors are mounted on the mounting plate using flexible ties.
  • first and second gripping members are in an approximate V-shape, in which, the V pointed end parts are mounted on the first and second gripping member shafts, and the two V not-pointed end parts face towards the object to be gripped and form the first and second gripping surfaces, respectively.
  • the first and second gripping members are driven to rotate in opposite directions, so that both the first and second gripping members tend to lift the object while moving from the release position to the gripping position.
  • the gripper mechanism is made suitable for use for programmable educational robotcars, model robots, industrial robots, or the like, and the first and second gripping electric motors are powered by a battery pack located on the programmable educational robot car through a DC-DC boost converter circuit to increase the voltage supplied to the first and second gripping electric motors, by which increasing their maximum torque when gripping the object to be gripped without increasing the nominal voltage, capacity, and size of the battery pack.
  • Figure 1 is a perspective view showing a gripper mechanism for a robot according to a preferred embodiment of the present invention
  • Figure 2 is an exploded-perspective view of the details showing the robot gripper mechanism according to a preferred embodiment of the present invention
  • Figure 3 is a perspective view showing the present robot gripper mechanism in the state of approaching an object to be gripped
  • Figure 4 is a perspective view showing the present robot gripper mechanism in the gripping state and lifting an object to be gripped;
  • Figure 5 is a schematic diagram showing the use of a DC-DC boost converter circuit according to a preferred embodiment of the present invention.
  • Figures 6A to 6C are perspective views showing the different states which the present robot gripper mechanism grips, lifts, and shakes an object to be gripped.
  • a robot gripper mechanism 1000 includes main components: a mounting bracket 1, a first gripping member 8, a second gripping member 9, a first gripping member shaft 6, a second gripping member shaft 7, and a gripping member shaft driving assembly with a first gripping electric motor 2 and a second gripping electric motor 3.
  • the first and second gripping electric motors 2, 3 may be commercially available small servomotors, for example, small-servomotors SG90.
  • the first gripping member 8 and the second gripping member 9 are made of elastic materials, wherein the first and second gripping members 8, 9 include first and second gripping surfaces, respectively, for gripping an object to be gripped at both sides of the object, by contacting and pressing the first and second gripping surfaces against the both sides of the object to be gripped.
  • the first gripping member 8 is mounted on the first gripping member shaft 6, and the second gripping member 9 is mounted on the second gripping member shaft 7, respectively.
  • the first and second gripping member shafts 6, 7 are the shafts of the first and second gripping electric motors 2, 3, respectively.
  • the mounting bracket 1 includes a mounting plate for mounting the first and second gripping electric motors 2, 3.
  • the first and second gripping electric motors 2 and 3 are mounted on the mounting plate of the mounting bracket 1 by using flexible ties 4, 5.
  • the flexible ties 4, 5 can be ties made of plastic, or the like.
  • the first and second gripping member shafts 6, 7 can be mounted and rotationally supported on the mounting bracket 1.
  • the gripping member shaft driving assembly (the first and second gripping electric motors 2, 3) can drive the first and second gripping member shafts 6, 7 to rotate around axes along with axial directions of the first and second gripping member shafts 6, 7 respectively.
  • the first gripping member shaft 6 and the second gripping member shaft 7 are basically arranged parallel to each other and kept in fixed positions during operation, i.e. , during rotating, the axes are parallel to each other and kept at a constant distance from each other.
  • the first and second gripping members 8, 9 are arranged to protrude from the first and second gripping member shafts 6, 7, respectively, with the first and second gripping surfaces protruding the farthest from the first and second gripping member shafts 6, 7, so that when the first and second gripping members 8, 9, rotated around the first and second gripping member shafts 6, 7, reach a gripping position, the first and second gripping surfaces are opposite to each other and at the closest distance from each other between first and second gripping member shafts 6, 7, and, when the first and second gripping members 8, 9, rotated around the first and second gripping member shafts 6, 7, come out of the gripping position, the first and second gripping surfaces move away from each other.
  • each of the first and second gripping surfaces is not necessarily a flat surface, but may be any one or more surfaces as long as the first and second gripping surfaces tend to press and grip the both sides of the object to be gripped.
  • Figures 3 and 4 show the robot gripper mechanism according to the present invention in a state of approaching a object to be gripped to perform gripping the object, state of gripping and lifting the object.
  • the robot gripper mechanism 1000 of the present invention moves to a position of approaching a object to be gripped 2000.
  • the first and the second gripping members 8, 9 are in a gripping release position, where the closest distance between them is usually greater than the size of the object 2000, by which, it is possible to move the robot gripper mechanism 1000 to approach the object 2000, so that the first and second gripping members 8, 9 are located on either side (both sides) of the object 2000 (see Figure 3) for gripping the object subsequently.
  • the first and second gripping members 8, 9 are in an approximate V-shape, wherein the V pointed end parts are mounted on the first and second gripping member shafts 6, 7, respectively, and the two V not-pointed end parts face towards the object to be gripped 2000.
  • the two V not-pointed end parts basically form the first or second gripping surfaces, respectively. More specifically, the first gripping surface or second gripping surface are defined as consisting of the surfaces of the two V not- pointed end parts and the two-walled inner surface inside of the V.
  • the first and second gripping members 8, 9 in this preferred embodiment are constructed so that when the first and second grips 8, 9 rotate from a gripping release position to a gripping position, they will come into contact with the object to be gripped 2000, elastically deformed for gradually pressing the object to be gripped 2000, and at the gripping position, the first and second gripping surfaces are pressed against the sides of the object 2000, so that the object 2000 elastically deforms and presses the first and second gripping members 8, 9 towards the first and second gripping member shafts, respectively, thereby producing elastic forces tightly applying to the both sides of the object 2000 for gripping the object 2000.
  • the surfaces of the two V not-pointed end parts will firstly contact with the gripped object 2000 (see Figure 3), next, the first and second gripping members 8, 9 will elastically deform when gradually pressing the object 2000, when at the gripping position, they will no longer have a V-shape but can have a shape that the two V not- pointed end parts are spread out (see Figure 4), at this time, the surface of the twowalled inner surface of the V will lean and press against the object 2000.
  • first and second gripping members 8, 9 are V-shaped
  • their elastic deformation can be any elastic deformation when pressing against the object to be gripped 2000, so that the first and second surfaces can also be defined accordingly and also the last part of the surface, that rests on and presses against the object 2000 in the gripping position can also be defined differently, varies depending on the size, material of the first and second gripping members 8, 9, and the object to be gripped 2000.
  • the stated elastic forces are directed through the rotational axes of the first and second gripping member shafts 6, 7 so that the elastic forces do not produce a torque on the first and second gripping member shafts 6, 7, so that when reaching the gripping position, the first and second gripping member shafts 6, 7 can be left free and do not need to maintain the driving force by the gripping member shaft driving assembly, but still maintain a stable gripping state of the object to be gripped 2000, based on the elastic forces and the relative position between the first and second grip members 8, 9, the first and second gripping member shafts 6, 7, and the object to be gripped 2000.
  • the gripping member shaft driving assembly (the first and second gripping electric motors 2, 3) drives the first and second gripping members 8, 9 to the gripping and holding positions of the object 2000 in the middle
  • the gripping member shaft driving assembly can be disconnected from the power supply, meanwhile the first and second gripping members 8, 9 can still maintain the gripping state stably and firmly for a long time. This is beneficial in reducing the power consumption of the gripping member shaft driving assembly significantly compared to known techniques.
  • first and second gripping members 8, 9 are driven to rotate in the opposite directions (see arrows indicating the rotational directions X1 , X2 in Figure 3), so that both tend to lift the object to be gripped while moving from the gripping release position to the gripping position.
  • the gripping release position is understood herein as ones where the object is not gripped stably, it is thus understood as including the positions approaching the object to be gripped 2000 and the positions gradually pressing on the object 2000 without reaching the stable gripping position of the object (e.g, the gripping position as defined in Figure 4, for example).
  • the first and second gripping members 8, 9 are rotationally driven to come into contact with the object to be gripped 2000, the first gripping member 8 rotates in the direction of the arrow X1 (clockwise) and tends to push the right side of the object 2000 upwards, the second gripping member 9 rotates in the direction of the arrow X2 (counterclockwise) and tends to push the left side of the object 2000 downwards.
  • the first and second gripping members 8, 9 gradually press firmly against the object to be grisped 2000 while lifting up the object 2000, and reaching the gripping position and holding the object in the lifting state as shown in Figure 4.
  • the preseny robot gripper mechanism can basically omit the use of connecting rods or gears to help the gripping members rotate relative to each other as above-described in the prior art.
  • the present robot gripper mechanism can be made compact and at the same time construction of the gripping members can be simplified which are essentially mounted on the first and second gripping member shafts of the driving electric motors.
  • the mounting bracket 1 can be made in the form of a mounting plate with slots 14, 15 for the flexible ties, and areas 12, 13 for placing the gripping electric motors.
  • the first and second gripping electric motors 2, 3 have mounting ears 24, 35 with the slots.
  • the flexible ties 4, 5 have caps 42, 53.
  • the first and second gripping members 8, 9 are mounted on the first and second gripping member shafts 6, 7 using first and second mounting bars 26, 37 respectively, the first and second mounting bars 26, 37 are made with mounting holes for inserting the shafts (indicators 6, 7) of the first and second gripping electric motors 2, 3 therein respectively.
  • the first and second gripping members 8, 9 are made with mounting slots 86, 97 for inserting the first and second mounting bars 26, 37 respectively.
  • the present mechanism gripper for robots may be supplied to users either in a pre-assembled form or in separate parts from which the users perform robot assembling.
  • the assembling of the present robot gripper mechanism from the separate parts is very simple and easy.
  • the first and second gripping electric motors 2, 3 can be placed in the areas 12, 13.
  • the flexible ties 4, 5 are pulled through the slots of the mounting ears 24, 35, and the mounting slots 14, 15 of the mounting plate, so that the caps 42, 53 are intercepted in front of the slots of the mounting ears 24, 35 and fixed the first and second gripping electric motors 2, 3 to the mounting bracket 1.
  • the first and second mounting bars 26, 37 can be mounted to the first and second gripping member shafts 6, 7 (which are the axes of the first and second gripping electric motors 2, 3).
  • the outer ends of the first and second mounting bars 26, 37 can be inserted into the mounting slots 86, 97 for mounting the first and second gripping members 8, 9 and completing the assembling of the present robot gripper complexism.
  • housings of the first and second gripping electric motors 2 and 3 can form a part of the mounting bracket 1. Accordingly, the robot gripper mechanism can be made with a simplified structure, compactness, ease of assembling, ease of use, reduced power consumption, and secure, long-term stable operation.
  • the present robot gripper mechanism combines simultaneous grasping and lifting operations, when lifting, it only lifts the object.
  • gripping mechanism and lifting mechanism are different to each other, so when lifting the object, both the object and the gripping mechanism must be lifted simultaneously, that is, the part to be lifted is basically heavier and bulkier which can cause more power consumption of driving electric motors.
  • the present robot gripper mechanism can be made suitable for use in a programmable educational robot car.
  • the present invention is not limited thereint, the robot gripper mechanism may be made suitable for use in different types of robots.
  • the programmable educational robot car could be one provided in Vietnamese patent application No. 1-2022-01315 (by the same applicant) the entireties of which are incorporated by reference herein and may be incorporated into the present solution in any known way.
  • the programmable educational robot may include: a robot chassis includes a battery pack and two side panels, in which the two side panels are mounted and gripped to both side of the battery pack; two driving wheel assemblies for driving the robot to move, where each of the driving wheel assemblies includes a driving motor whose shaft is directly attached to the driving wheel, in which the two driving motors are fastened to the two side panels to fit the two driving wheel assemblies into the robot chassis; a power circuit block whose power is derived from the said battery pack; a controlling circuit block includes a pre-programmed program for controlling the robot operation; charaterized is that the said controlling circuit block includes two driving motor circuits to control the two driving wheel assemblies whose operation are independent of each other, wherein: when the two driving wheels are controlled so that the two driving wheels rotate at the same speed, the robot will move straight, when the two driving wheels are controlled so that the two driving wheels rotate at different speeds, or one of the two driving wheels is temporarily stopped, the robot moves around to the left, or to the right, when the two driving
  • the above-mentioned robot also includes a static sliding base fixed to the robot chassis, the static sliding base is arranged to combine with the two driving wheels so as to stabilize the robot on the surface on which it moves.
  • the static sliding base serves as equivalent role and substitution for multidirectional wheel usage.
  • controlling circuit block is configured to allow changing, updating, or loading the program that drives the robot operation.
  • the power supply block includes a power board, which has a connector that is permanently attached to the power board, to connect to the corresponding battery pack connector, and to secure the power board with the battery pack.
  • the power board may also include snap joints to secure with that of the respective the two side panels so that power board is secured with the two side panels.
  • the controlling circuit block includes a controlling circuit board, which includes the snap joints to secure with that of the two side panels to secure the controlling circuit board with the two side panels.
  • the driving motors are step motors with mounting ears.
  • the above-mentioned robot also includes a fixed belt to fasten around the two side panels, the battery pack and the mounting ears of the above-mentioned step motors for attaching and gripping the two driving wheel assemblies, the two side panels and the battery block together.
  • the above-mentioned robot also includes a sensor block for sensing the surrounding environment information to control the robot operation based on the information.
  • the present gripper section for robots can be adapted or modified for various purposes of a programmable educational robot.
  • the mounting plate of the mounting bracket 1 can be constructed to be suitable to mount or fit into the two side panels of the programmable educational robot, and/or the mounting plate can be constructed with a sensor block mounted thereon, for example.
  • the first and second gripping electric motors 2, 3 are powered by the battery pack arranged on the programmable educational robot car through a boost circuit to boost the voltage supply for the first and second gripping electric motors 2, 3 respectively, thereby increasing their maximum torque when gripping the object 2000 without increasing the nominal voltage, capacity, and size size of the battery pack.
  • the first and second gripping members 8, 9 may be preferred to be made of soft, resilient, high surface friction materials, e.g. rubber or ethylene vinyl acetate foam (Ethylene Vinyl Acetate - EVA), and in combination with the conformation of the first and second gripping members 8, 9, for example an approximate V-like shape, torque requirements to produce an increased pressure on the object to be gripped 2000 can be somewhat smaller for which the first and second driving electric motors 2, 3 can respond to the normal voltage, e.g. 5V, supplied from the battery pack, used for servomotors type SG90, for example.
  • the normal voltage e.g. 5V
  • the shape and material of the first and second grippping members 8, 9 may however be changed, or the size of the object to be gripped 2000 may be larger than the predetermined one, or the present robot gripper mechanism can be applied for modeling purposes, industrial use, etc., which may lead to a requirement to increase the torque of the first and second gripping electric motors 2, 3 to drive the first and second gripping members 8, 9 from the position of approaching the object to be gripped 2000 to the position of gripping the object to be gripped 2000.
  • the use of the boost circuit is especially suitable to be able to respond well to operation of the robot gripper mechanisms in various arrangments.
  • the gripping member shaft driving assembly could use an electric motor and driving gears to drive the first and second gripping member shafts.
  • the first and second gripping members 8, 9 need not be made entirely of elastic material, but may be made from at least partly of elastic material, provided the elastic material part can elastically deform from the position of approaching to the position of gripping the object to be gripped.
  • a boost circuit is a circuit that transforms an input voltage into a larger output voltage.
  • Construction of the boost circuit may include an inductor, a semiconductor switch (for example, a MOSFET), that opens and closes at a fast rate, diodes, and a capacitor.
  • a semiconductor switch for example, a MOSFET
  • the boost circuit has an uncomplicated structure and does not use a large number of electronic components, so the size of the boost circuit is relatively compact, capable of being arranged next to the driving circuit board, or can also be integrated or arranged into the drive board without increasing the size of the driving board significantly.
  • the use of the boost circuits to increase the battery voltage supplied to the step motors, servomotors or corresponding actuators used in programmable educational robots does not substantially increase the overall size of robot according to the present invention, and could eliminate the need of increasing the nominal voltage, capacity, and size of the battery pack.
  • This is also beneficial in practical use, as commercially available batteries commonly used for programmable educational robots may not have the nominal voltage, required capacity, interchangeability of the batteries is considered not feasible without the boost circuit usage or similar solutions.
  • operating power ranges of the driving electric motors used in robots can be quite varied, for example the driving electric motors for robot movement may have relatively larger operating power ranges compared to that of the gripper mechanism. Therefore, more than one boost circuit can be used, wherein each of the boost circuits can be used to power one or more of the driving electric motors at a suitable operating power range.
  • the gripper mechanism of the present invention can be driven by one or two servomotors that can operate with voltages of up to 6V or 9V to increase gripping force when needed, separate boost circuit may be provided to provide power for the driving of the present gripper mechanism.
  • Figure 5 shows a schematic diagram of an embodiment using a boost circuit according to a preferred embodiment of the present invention.
  • the battery power supply and the power supply circuit 100 provide a power supply with a voltage according to the nominal battery voltage, for example between 3.7 and 6V, to the boost circuit 200.
  • the circuit 200 adjusts to increase the required voltage, for example between 6 and 9V, or 12 to 18V to supply the controlling circuit 300.
  • the controlling circuit provides power, based on a boost regulated voltage, to the driving motor 400 and controls operation of the motor 400 at the same time.
  • the battery and power circuit 100 can represent the battery pack and the power circuit block
  • the motor 400 can represent the driving motors of active wheels of the programmable educational robot and/or gripping electric motors
  • the boost circuit 200 and the controlling circuit 300 can be components in the controlling circuit block or board.
  • the boost circuit 200 could be an available IC with the commercial designation MT3608 (IC MT3608)
  • the controlling circuit 300 could be an available IC with the commercial designation A4988 (IC A4988)
  • the driving motor 400 can be either a step motor or a similarly available electric motor.
  • a low voltage source of about 5V (3.7 to 6V) can drive a step motor, for example, of 28BYJ-48 type, up to speeds of 70 to 80 rpm, or even more, which essentially satisfies the speed and torque sufficient for moving the robot to perform extensive operations including more complex tasks such as ones discussed in the description of prior art above.
  • Electric motors to drive other mechanisms or to perform other robot functions may also require less power than that of driving the robot. Therefore, the driving electric motors, e.g. for the gripper mechanism can use servomotors, and the boost circuit in the case of low voltage sources of about 5V (3.7 to 6V) can be used to drive the servomotor to be operated within a voltage range of up to 6V or 9V. Additionally, the servomotors each can be equipped with a motor controlling circuit. Therefore, the controlling circuit 300 according to the embodiment illustrated in Figure 5 can be omitted.
  • the present invention is not limited to specific types of motors or operating voltage ranges as described above, but they can be selected/designed in accordance with actual requirements.
  • driving electric motors for different purposes can be used with separate boost circuits if the power ranges are relatively different, or a shared boost circuit can be used if the power ranges are the same or are suitably similar.
  • the robot of the present invention can only need only a power source from a low-voltage battery, for example, 3.7V or 5V, which is a common, neat, convenient, and easy-to-find battery power source compared to other power sources from high voltage batteries (e.g. 12V), for use in both of the controlling circuit and driving motors.
  • a low-voltage battery for example, 3.7V or 5V
  • high voltage batteries e.g. 12V
  • the voltage supplied to the driving motor is always stable regardless of various high and low battery voltages (fully charged or almost run out of battery), which helps the robot move stably.
  • the advanced voltage level for the motor can be flexibly adjusted according to needs of the robot of a slower, more batterysaving configuration (reduced voltage level) or a faster, stronger, more batteryconsuming configuration (increased voltage level) without changing the battery source, but some of auxiliary components connected to the boost circuit, for example two resistors in the boost circuit.
  • the components in the boost circuit and controlling circuit are all common and easy-to-find components.
  • first and second gripping members 8, 9 are driven by two independent driving electric motors 2, 3, the first and second gripping members 8, 9 are not necessarily always rotated symmetrically to each other, which may deviate from their symmetrical position.
  • positions that are slightly out of the symmetrical one can also grip and hold the object steadily, in other words gripping and lifting the object can be performed easier and does not require a too high level of precision.
  • the first and second gripping members 8, 9 not only grip and hold the object fixedly, but they can be driven to “shake” the object. At this time, if one of the electric motors rotates slightly upwards, and the other rotates slightly downwards, the first and second gripping members 8, 9 will be driven to tilt the object slightly left or right. Repeating the steps will cause the object to be shaken slightly.
  • Figures 6A to 6C show different states that the present robot gripper mechanism 1000 grips, lifts, and shakes the object to be gripped 2000.
  • first gripping member 8 when the first gripping member 8 is driven upwards and the second gripping member 9 is driven downwards, which will tilt the object to be gripped 2000 to the left (or shake to the left), when the first gripping member 8 is driven downwards and the second gripping member 9 is driven upwards, which will cause the object to be gripped 2000 to the right, through the symmetrical position (see Figure 6B), and tilt to the right (or shake to the right).
  • the first and second gripping members 8, 9 are driven in the opposite direction to shake the object to be gripped 2000 from the lilted (inclined) position to the right through the symmetrical position and to the lilted position to the left.
  • the steps can be repeated over a predetermined time or condition to meet a given requirement.

Landscapes

  • Engineering & Computer Science (AREA)
  • Robotics (AREA)
  • Mechanical Engineering (AREA)
  • Manipulator (AREA)

Abstract

A robot gripper mechanism comprising first and second gripping members made of elastic material is provided. Each of the gripping members, which is mounted on a rotational axis of a driving electric motor, is rotationally driven from an approach position to an object to be grippedgripped, elastically deformed to gradually press the object to be gripped to a gripping position. In the gripping position, elastic forces, caused by the elastic deformation, each has a direction through the center of the rotational axis of the driving electric motor respectively, such that no torque is produced on the rotational axis of the driving electric motor. As a result, when reaching the gripping position, the rotational axes of the drive electric motors can be left free and without maintaining power consumption, while maintaining a stable gripping state of the object to be gripped, based on the elastic forces and relative positions between the first and second gripping members, the rotational axes of the driving electric motors, and the object to be gripped.

Description

A ROBOT GRIPPER MECHANISM
FIELD OF THE INVENTION
The present invention relates to a robot gripper mechanism, more specifically to the robot gripper mechanism suitable for use in programmable educational robot cars, which may be collectively referred to as programmable educational robots.
DESCRIPTION OF PRIOR ART
It is known that programmable educational robots are now widely used in Science, Technology, Engineering and Mathematics (STEM) education, for example, a robot family called mBot.
In general, mBots are popularly used as STEAM educational robots for beginners, for example, children, to make teaching and learning of robot programming being simpler and more fun. The produced mBots have a simplified structure that allows children of appropriate ages to assemble themselves according to the instructions to form a completed educational robot, and practice programming concepts and techniques for the mBots. This helps children understand robot construction, electronic components, fundamentals of programming, thereby help develop logical thinking and design skills.
Similar to mBots, programmable educational robots typically comprise a robot chassis, battery pack, wheel assemblies , driver block, and sensor block. The robot chassis can be made from frames and/or panels. The battery pack can be mounted in the blank space inside of the robot chassis to reduce an overall size of the robot. The driver block and the sensor block control activities of the robot according to information of the sensor, sensed from the surrounding environment, for example, the driver block controls the robot to follow road markings on which the robot moves or to avoid an obstacle, etc., based on obtained identification information of the road markings or the obstacle from the sensor block, for example. The wheel assemblies are powered by the battery pack and are driven to generate a suitable torque on the wheels from which the robot moves.
Currently, most of the battery packs of programmable educational robots use rechargeable Lithium polymer (Li-po) batteries, whose voltages ranging from 3.7V to 6V used to power circuits, electronic components, and step motors to drive the wheels. Batteries of a voltage of about 3.7V are commonly used for small-sized programmable educational robots, while that of a voltage of about 6V are commonly used for largesized programmable educational robots. This is attributed to the fact that in order to increase the output voltage of the battery, it is necessary to increase the size of the battery significantly, which requires a significantly large blank space inside of the robot chassis to arrange the battery pack therein; in other words, the robot chassis of a significantly larger size is required. Meanwhile, programmable educational robots need to be aimed at compactness to facilitate transportation, assembly, control operation, and reducing production costs.
Programmable educational robots can help beginners approach programming, for example, children who learn and practice programming techniques based on Scratch software, which can help them either quickly learn how to code, or become capable doing advanced programming using Arduino, for example.
It can be seen that, for a battery voltage in the range of 3.7V to 6V, although it is possible to drive a step motor to generate a torque at a basic level which satisfies activities of a programmable educational robot according to requirements of practical exercises in education and entertainment, for example, moving according to control signals of a remote controller, moving by itself according to a road map with road lines, moving by itself to follow pre-programmed trajectories, avoiding obstacles, producing sound, light, or the like.
However, programmable educational robots can completely be applied to do more complex tasks for learning and entertainment due to their potential, for example, they can be programmed to participate in a competitive game, wherein they, for example, may need to accelerate, push objects to a predetermined position, move on uneven surfaces, etc. In order to respond well to more complex tasks, there is a problem with current programmable educational robots, which is difficult for them to increase the supplied power from the battery to the step motor; in other words, it is difficult to increase the torque of the step motor in certain times, for example, when acceleration or increasing load of the motor is required, because it is required to increase the size of the battery pack so as to have an increase of the battery voltage and the overall size of the robot thus may not be feasible or desirable.
Additionally, in some applications for educational robots, there is a need to use gripper mechanisms to grip, lift, and move objects from one location to another location, for example, ones for gripping, grabbing, holding objects, or the like.
To the present, some commercially available gripper mechanisms typically use a servomotor to rotate two jaw-tips horizontally. The two jaw-tips are mounted on a gripper holder, but still need to be rotate freely relative to the holder by a certain angle. The mechanisms therefore require pivot parts, or if bolts and nuts are used only, they need to be tightened just enough, so that the bolts and nuts still hold the jaw-tips, but not so tight that prevent the jaw-tips from rotating. In this case, the assembly and usage are complicated because the bolts and nuts are only tightened enough. Moreover, after using for a while, the bolts and nuts tend to loosen gradually, they are thus required to regularly re-tightened, causing inconvenience in use.
Several gripper mechanisms have been described in the patents and patent applications, such as CN208342875U, CN213081498U, CN108582137A, CN106826881 A, or CN214352514U, which generally use two gripping members (jaws) with jaw-tips to grip and grasp an object to be gripped/grasped by adjusting a distance between the two gripping members so that the jaw-tips grip both sides of the object to be gripped/grasped. The two gripping members are linked together through linked bars or gears so that they can be rotated relative to each other. When the wo gripping members rotate relative to each other, the distance between the gripping jaw-tips will be varied so as to grip the object to be picked up or release the object to be picked up. In this way, the jaw-tips always need to remain a gripping force for tightly applying the object, and in order to maintain such a gripping force, the servomotor needs to be driven for continuous operation (constant power consumption) to produce a required torque to press the gripping jaw-tips against the object.
In addition, after the jaw-tips gripped the object, if the object is to be lifted for easy movement, they are often mounted on a pivot together with a servomotor (adding a extra degree of freedom), so that the entire jaw mechanism can be turned up and down. This method also requires further supporting mechanical components, pivots for assembly of the mechanism, which increase the number of components and complexity in manufacturing, assembling, or repairing process.
Therefore, there is a need for a gripper mechanism which is simple in structure, compact, easy to assemble, easy to use, reduces power consumption, and is capable of secure, long-term stable operation.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a gripper mechanism for a robot, which can overcome one or more of the above-mentioned problems.
Another object of the present invention is to provide a robot gripper mechanism, which is simple in structure, compact, easy to assemble, easy to use, reduces power consumption, and is capable of secure, long-term stable operation.
Yet another object of the present invention is to provide a robot gripper mechanism, which is suitable to use for programmable educational robots, using a DC- DC boost converter circuit to increase the battery voltage supplied to the drive motor, thereby preventing a significant increase in the overall size of the robot in increasing the battery voltage.
It should be understood that the present invention is not limited to the aforementioned objects, but may also include other objects as understood by one of ordinary skilled in the art, based on what described below.
To achieve one or more of the foregoing objects, the present invention provides a robot gripper mechanism comprising: a first gripping member and a second gripping member are made of elastic material, in which the first and second gripping members have first and second gripping surfaces, respectively, for gripping both sides of an object to be gripped, by contacting and pressing the first and second gripping surfaces against the both sides of the object to be gripped; a first gripping member shaft for mounting the first gripping member and a second gripping member shaft for mounting the second gripping member; a mounting bracket for mounting and rotationally supporting the first and second gripping member shafts thereon; a gripping member shaft driving assembly to rationally drive the first and second gripping member shafts around axes along with axial directions of the first and second gripping member shafts respectively; in which: the first gripping member shaft and the second gripping member shaft are arranged basically parallel to each other and kept in a fixed position during operation; the first and second gripping members are arranged to protrude from the first and second gripping member shafts respectively, with the first and second gripping surfaces protruding the furthest from the first and second gripping member shafts, such that when the first and second gripping members, rotated around the first and second gripping member shafts, reach a gripping position, the first and second gripping surfaces are opposite to each other and at the closest distance between the first and second gripping member shafts, when the first and second gripping members rotated around the first and second gripping member shafts come out of the gripping position, the first and the second gripping surfaces move away from each other, characterized in that: the first and second gripping members are constructed so that when the first and second gripping members are rotated from a gripping release position to a gripping position, they will come to contact with the object to be gripped, elastically deformed to gradually press the object to be gripped, and at the gripping position, the first and second gripping surfaces are pressed against the both sides of the object so that the object elastically deforms and presses the first and second gripping members towards the first and second gripping member shafts, respectively, thereby producing elastic forces tightly pressing to the both sides of the object to be gripped for gripping the object, wherein, at the gripping position, the said elastic forces are directed through the rotational axes of the first and second gripping member shafts such that the elastic forces do not produce a torque acting on the first and second gripping member shafts, whereby when reaching the gripping position, the first and second gripping member shafts are left free and do not need to maintain a force driven by the gripping member shaft driving assembly, while still maintain a stable gripping state of the object to be gripped, based on the elastic forces and relative positions of the first and second gripping members, the first and second gripping member shafts, and the object to be gripped.
In an embodiment, the gripping member shaft driving assembly comprises a first gripping electric motor to drive the first gripping member shaft and a second gripping electric motor to drive the second gripping member shaft.
In an embodiment, the mounting bracket comprises a mounting plate for mounting the first and second gripping electric motors, and the motor shafts (or axes) of the first and second gripping electric motors serve as the first and second gripping member shafts.
In an embodiment, the first and second gripping members are mounted on the first and second gripping member shafts using first and second mounting bars, respectively, wherein, the first and second gripping members are constructed with mounting slots for inserting the first and second mounting bars, respectively, the first and second mounting bars are constructed with mounting holes for inserting the motor shafts of the first and second gripping electric motors, respectively.
Preferably, the first and second gripping electric motors are mounted on the mounting plate using flexible ties.
In an embodiment, the first and second gripping members are in an approximate V-shape, in which, the V pointed end parts are mounted on the first and second gripping member shafts, and the two V not-pointed end parts face towards the object to be gripped and form the first and second gripping surfaces, respectively.
Preferably, the first and second gripping members are driven to rotate in opposite directions, so that both the first and second gripping members tend to lift the object while moving from the release position to the gripping position.
In an embodiment, the gripper mechanism is made suitable for use for programmable educational robotcars, model robots, industrial robots, or the like, and the first and second gripping electric motors are powered by a battery pack located on the programmable educational robot car through a DC-DC boost converter circuit to increase the voltage supplied to the first and second gripping electric motors, by which increasing their maximum torque when gripping the object to be gripped without increasing the nominal voltage, capacity, and size of the battery pack.
BRIEF DESCRIPTION OF DRAWINGS
Figure 1 is a perspective view showing a gripper mechanism for a robot according to a preferred embodiment of the present invention; Figure 2 is an exploded-perspective view of the details showing the robot gripper mechanism according to a preferred embodiment of the present invention;
Figure 3 is a perspective view showing the present robot gripper mechanism in the state of approaching an object to be gripped;
Figure 4 is a perspective view showing the present robot gripper mechanism in the gripping state and lifting an object to be gripped;
Figure 5 is a schematic diagram showing the use of a DC-DC boost converter circuit according to a preferred embodiment of the present invention; and
Figures 6A to 6C are perspective views showing the different states which the present robot gripper mechanism grips, lifts, and shakes an object to be gripped.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Advantages, effects and nature of the present invention will be described in detail through a detailed description of preferred embodiments with reference to the accompanying drawings. In Figures, the same reference numerals are intended to indicate the same or equivalent components or elements and are used uniformly throughout the description, by which in some of the Figures or parts of the Figures may not appear one or more of the reference numerals for the purposes of simplicity and convenience in showing the different components or operating principles of the present invention. In such case, the relationship between specific components or elements and the reference numerals thereof may be clearly illustrated with reference to other Figures or other parts of the Figures. Additionally, the components and elements shown in the Figures do not represent the actual size and shape, some of the components or elements will be enlarged and may be represented by reduced blocks for illustrative purposes and convenience of the present description. Therefore, it should be understood that the embodiments described in the description are intended as examples only to aid in a better understanding of the nature and advantages of the present invention, without limiting the scope of the present invention to the embodiments described herein.
Spatial terms, such as “front", “behind”, “beside", “length”, “width”, “height”, “above”, “on”, or any similar terms, may be used herein solely for descriptive purposes, and, by which, to describe the spatial relative relations of one element to other element(s) as illustrated in the Figures. Obviously, roles and positions of the terms are interchangeable in the description of an actual object according to the present invention, for example, if the object illustrated in the Figures is rotated 180 degrees, elements described as “front” or “rear” are interchangeable in the description. Therefore, the exemplary spatial terms for the description may also imply meanings denoting other spatial relations, depending on orientation of the described object, for example, the term “front" may imply the meaning of “behind”. Figures 1 and 2 show a robot gripper mechanism according to a preferred embodiment of the present invention.
As shown in the Figures, a robot gripper mechanism 1000 according to this preferred embodiment includes main components: a mounting bracket 1, a first gripping member 8, a second gripping member 9, a first gripping member shaft 6, a second gripping member shaft 7, and a gripping member shaft driving assembly with a first gripping electric motor 2 and a second gripping electric motor 3. The first and second gripping electric motors 2, 3 may be commercially available small servomotors, for example, small-servomotors SG90.
The first gripping member 8 and the second gripping member 9 are made of elastic materials, wherein the first and second gripping members 8, 9 include first and second gripping surfaces, respectively, for gripping an object to be gripped at both sides of the object, by contacting and pressing the first and second gripping surfaces against the both sides of the object to be gripped. The first gripping member 8 is mounted on the first gripping member shaft 6, and the second gripping member 9 is mounted on the second gripping member shaft 7, respectively.
According to this preferred embodiment, the first and second gripping member shafts 6, 7 are the shafts of the first and second gripping electric motors 2, 3, respectively. The mounting bracket 1 includes a mounting plate for mounting the first and second gripping electric motors 2, 3. Preferably, the first and second gripping electric motors 2 and 3 are mounted on the mounting plate of the mounting bracket 1 by using flexible ties 4, 5. The flexible ties 4, 5 can be ties made of plastic, or the like.
By such a construction, the first and second gripping member shafts 6, 7 can be mounted and rotationally supported on the mounting bracket 1. The gripping member shaft driving assembly (the first and second gripping electric motors 2, 3) can drive the first and second gripping member shafts 6, 7 to rotate around axes along with axial directions of the first and second gripping member shafts 6, 7 respectively.
As shown in the Figures, the first gripping member shaft 6 and the second gripping member shaft 7 are basically arranged parallel to each other and kept in fixed positions during operation, i.e. , during rotating, the axes are parallel to each other and kept at a constant distance from each other. The first and second gripping members 8, 9 are arranged to protrude from the first and second gripping member shafts 6, 7, respectively, with the first and second gripping surfaces protruding the farthest from the first and second gripping member shafts 6, 7, so that when the first and second gripping members 8, 9, rotated around the first and second gripping member shafts 6, 7, reach a gripping position, the first and second gripping surfaces are opposite to each other and at the closest distance from each other between first and second gripping member shafts 6, 7, and, when the first and second gripping members 8, 9, rotated around the first and second gripping member shafts 6, 7, come out of the gripping position, the first and second gripping surfaces move away from each other. It should be understood that each of the first and second gripping surfaces is not necessarily a flat surface, but may be any one or more surfaces as long as the first and second gripping surfaces tend to press and grip the both sides of the object to be gripped.
Figures 3 and 4 show the robot gripper mechanism according to the present invention in a state of approaching a object to be gripped to perform gripping the object, state of gripping and lifting the object.
As shown in the Figures, the robot gripper mechanism 1000 of the present invention moves to a position of approaching a object to be gripped 2000. In order to approach the object 2000, the first and the second gripping members 8, 9 are in a gripping release position, where the closest distance between them is usually greater than the size of the object 2000, by which, it is possible to move the robot gripper mechanism 1000 to approach the object 2000, so that the first and second gripping members 8, 9 are located on either side (both sides) of the object 2000 (see Figure 3) for gripping the object subsequently.
Preferably, the first and second gripping members 8, 9 are in an approximate V-shape, wherein the V pointed end parts are mounted on the first and second gripping member shafts 6, 7, respectively, and the two V not-pointed end parts face towards the object to be gripped 2000. The two V not-pointed end parts basically form the first or second gripping surfaces, respectively. More specifically, the first gripping surface or second gripping surface are defined as consisting of the surfaces of the two V not- pointed end parts and the two-walled inner surface inside of the V.
The first and second gripping members 8, 9 in this preferred embodiment are constructed so that when the first and second grips 8, 9 rotate from a gripping release position to a gripping position, they will come into contact with the object to be gripped 2000, elastically deformed for gradually pressing the object to be gripped 2000, and at the gripping position, the first and second gripping surfaces are pressed against the sides of the object 2000, so that the object 2000 elastically deforms and presses the first and second gripping members 8, 9 towards the first and second gripping member shafts, respectively, thereby producing elastic forces tightly applying to the both sides of the object 2000 for gripping the object 2000. When starting to contact with the object 2000, the surfaces of the two V not-pointed end parts will firstly contact with the gripped object 2000 (see Figure 3), next, the first and second gripping members 8, 9 will elastically deform when gradually pressing the object 2000, when at the gripping position, they will no longer have a V-shape but can have a shape that the two V not- pointed end parts are spread out (see Figure 4), at this time, the surface of the twowalled inner surface of the V will lean and press against the object 2000.
It is to be appreciated that the present invention is not limited therein, in the embodiments, where the first and second gripping members 8, 9 are V-shaped, their elastic deformation can be any elastic deformation when pressing against the object to be gripped 2000, so that the first and second surfaces can also be defined accordingly and also the last part of the surface, that rests on and presses against the object 2000 in the gripping position can also be defined differently, varies depending on the size, material of the first and second gripping members 8, 9, and the object to be gripped 2000.
In this preferred embodiment, as clearly shown in Figure 4, when in the gripping position, the stated elastic forces are directed through the rotational axes of the first and second gripping member shafts 6, 7 so that the elastic forces do not produce a torque on the first and second gripping member shafts 6, 7, so that when reaching the gripping position, the first and second gripping member shafts 6, 7 can be left free and do not need to maintain the driving force by the gripping member shaft driving assembly, but still maintain a stable gripping state of the object to be gripped 2000, based on the elastic forces and the relative position between the first and second grip members 8, 9, the first and second gripping member shafts 6, 7, and the object to be gripped 2000.
As can be seen in Figure 4, when the first and second gripping members 8, 9 press firmly against the object to be gripped 2000 in the gripping position, there will be a retroaction force against the first and second gripping members 8, 9 in the direction of arrows F1 , F2 respectively. Since the direction of these forces passes through the rotational axes of the first and second gripping member shafts 6, 7 (in other words, in the radial direction of the rotational axis or through the center of the rotational axis), they are not exerts a torque on the first and second gripping member shafts 6, 7, that is, the first and second gripping member shafts 6, 7 can be left free without rotation. As a result, when the gripping member shaft driving assembly (the first and second gripping electric motors 2, 3) drives the first and second gripping members 8, 9 to the gripping and holding positions of the object 2000 in the middle, the gripping member shaft driving assembly can be disconnected from the power supply, meanwhile the first and second gripping members 8, 9 can still maintain the gripping state stably and firmly for a long time. This is beneficial in reducing the power consumption of the gripping member shaft driving assembly significantly compared to known techniques.
In this preferred embodiment, the first and second gripping members 8, 9 are driven to rotate in the opposite directions (see arrows indicating the rotational directions X1 , X2 in Figure 3), so that both tend to lift the object to be gripped while moving from the gripping release position to the gripping position.
The gripping release position is understood herein as ones where the object is not gripped stably, it is thus understood as including the positions approaching the object to be gripped 2000 and the positions gradually pressing on the object 2000 without reaching the stable gripping position of the object (e.g, the gripping position as defined in Figure 4, for example). When at the gripping release position, the first and second gripping members 8, 9 are rotationally driven to come into contact with the object to be gripped 2000, the first gripping member 8 rotates in the direction of the arrow X1 (clockwise) and tends to push the right side of the object 2000 upwards, the second gripping member 9 rotates in the direction of the arrow X2 (counterclockwise) and tends to push the left side of the object 2000 downwards. In this way, the first and second gripping members 8, 9 gradually press firmly against the object to be grisped 2000 while lifting up the object 2000, and reaching the gripping position and holding the object in the lifting state as shown in Figure 4.
It can be easily seen that, with the structure as described above, the preseny robot gripper mechanism can basically omit the use of connecting rods or gears to help the gripping members rotate relative to each other as above-described in the prior art. Thus, the present robot gripper mechanism can be made compact and at the same time construction of the gripping members can be simplified which are essentially mounted on the first and second gripping member shafts of the driving electric motors.
In reference back to Figure 2, the present robot gripper mechanism is shown in the form of an exploded-perspective view.
As shown in Figure 2, the mounting bracket 1 can be made in the form of a mounting plate with slots 14, 15 for the flexible ties, and areas 12, 13 for placing the gripping electric motors. The first and second gripping electric motors 2, 3 have mounting ears 24, 35 with the slots. The flexible ties 4, 5 have caps 42, 53. The first and second gripping members 8, 9 are mounted on the first and second gripping member shafts 6, 7 using first and second mounting bars 26, 37 respectively, the first and second mounting bars 26, 37 are made with mounting holes for inserting the shafts (indicators 6, 7) of the first and second gripping electric motors 2, 3 therein respectively. The first and second gripping members 8, 9 are made with mounting slots 86, 97 for inserting the first and second mounting bars 26, 37 respectively.
In general, the present mechanism gripper for robots may be supplied to users either in a pre-assembled form or in separate parts from which the users perform robot assembling. The assembling of the present robot gripper mechanism from the separate parts is very simple and easy.
As a specific example, the first and second gripping electric motors 2, 3 can be placed in the areas 12, 13. Next, the flexible ties 4, 5 are pulled through the slots of the mounting ears 24, 35, and the mounting slots 14, 15 of the mounting plate, so that the caps 42, 53 are intercepted in front of the slots of the mounting ears 24, 35 and fixed the first and second gripping electric motors 2, 3 to the mounting bracket 1. Then, the first and second mounting bars 26, 37 can be mounted to the first and second gripping member shafts 6, 7 (which are the axes of the first and second gripping electric motors 2, 3). Finally, the outer ends of the first and second mounting bars 26, 37 can be inserted into the mounting slots 86, 97 for mounting the first and second gripping members 8, 9 and completing the assembling of the present robot gripper machenism.
Additionally, housings of the first and second gripping electric motors 2 and 3 can form a part of the mounting bracket 1. Accordingly, the robot gripper mechanism can be made with a simplified structure, compactness, ease of assembling, ease of use, reduced power consumption, and secure, long-term stable operation.
As the present robot gripper mechanism combines simultaneous grasping and lifting operations, when lifting, it only lifts the object. As for known mechanisms in prior art, gripping mechanism and lifting mechanism are different to each other, so when lifting the object, both the object and the gripping mechanism must be lifted simultaneously, that is, the part to be lifted is basically heavier and bulkier which can cause more power consumption of driving electric motors.
As can be seen, the present robot gripper mechanism can be made suitable for use in a programmable educational robot car. However, the present invention is not limited thereint, the robot gripper mechanism may be made suitable for use in different types of robots.
In a preferred embodiment, the programmable educational robot car could be one provided in Vietnamese patent application No. 1-2022-01315 (by the same applicant) the entireties of which are incorporated by reference herein and may be incorporated into the present solution in any known way.
For convenience, some main features of the said programmable educational robot are described below.
In an exemplary preferred embodiment, the programmable educational robot may include: a robot chassis includes a battery pack and two side panels, in which the two side panels are mounted and gripped to both side of the battery pack; two driving wheel assemblies for driving the robot to move, where each of the driving wheel assemblies includes a driving motor whose shaft is directly attached to the driving wheel, in which the two driving motors are fastened to the two side panels to fit the two driving wheel assemblies into the robot chassis; a power circuit block whose power is derived from the said battery pack; a controlling circuit block includes a pre-programmed program for controlling the robot operation; charaterized is that the said controlling circuit block includes two driving motor circuits to control the two driving wheel assemblies whose operation are independent of each other, wherein: when the two driving wheels are controlled so that the two driving wheels rotate at the same speed, the robot will move straight, when the two driving wheels are controlled so that the two driving wheels rotate at different speeds, or one of the two driving wheels is temporarily stopped, the robot moves around to the left, or to the right, when the two driving wheels are controlled so that one driving wheel is stationary while the other driving wheel rotates continuously, the robot will move in a circle, to the left, or to the right, each of the said driving motor circuits is powered from the power circuit block through a turbocharger circuit to increase the voltage supplied to the corresponding driving motor, thereby increasing the maximum torque of the driving wheel without increase the nominal voltage, capacity, and size of the battery pack.
In an exemplary specific embodiment, the above-mentioned robot also includes a static sliding base fixed to the robot chassis, the static sliding base is arranged to combine with the two driving wheels so as to stabilize the robot on the surface on which it moves. The static sliding base serves as equivalent role and substitution for multidirectional wheel usage.
Preferably, the controlling circuit block is configured to allow changing, updating, or loading the program that drives the robot operation.
Preferably, the power supply block includes a power board, which has a connector that is permanently attached to the power board, to connect to the corresponding battery pack connector, and to secure the power board with the battery pack.
The power board may also include snap joints to secure with that of the respective the two side panels so that power board is secured with the two side panels.
Preferably, the controlling circuit block includes a controlling circuit board, which includes the snap joints to secure with that of the two side panels to secure the controlling circuit board with the two side panels.
In an exemplary specific embodiment, the driving motors are step motors with mounting ears.
The above-mentioned robot also includes a fixed belt to fasten around the two side panels, the battery pack and the mounting ears of the above-mentioned step motors for attaching and gripping the two driving wheel assemblies, the two side panels and the battery block together.
In a exemplary specific embodiment, the above-mentioned robot also includes a sensor block for sensing the surrounding environment information to control the robot operation based on the information.
Obviously, the present gripper machenism for robots can be adapted or modified for various purposes of a programmable educational robot. For example, the mounting plate of the mounting bracket 1 can be constructed to be suitable to mount or fit into the two side panels of the programmable educational robot, and/or the mounting plate can be constructed with a sensor block mounted thereon, for example.
In a preferred embodiment, the first and second gripping electric motors 2, 3 are powered by the battery pack arranged on the programmable educational robot car through a boost circuit to boost the voltage supply for the first and second gripping electric motors 2, 3 respectively, thereby increasing their maximum torque when gripping the object 2000 without increasing the nominal voltage, capacity, and size size of the battery pack.
In certain embodiments, the first and second gripping members 8, 9 may be preferred to be made of soft, resilient, high surface friction materials, e.g. rubber or ethylene vinyl acetate foam (Ethylene Vinyl Acetate - EVA), and in combination with the conformation of the first and second gripping members 8, 9, for example an approximate V-like shape, torque requirements to produce an increased pressure on the object to be gripped 2000 can be somewhat smaller for which the first and second driving electric motors 2, 3 can respond to the normal voltage, e.g. 5V, supplied from the battery pack, used for servomotors type SG90, for example. In some events, the shape and material of the first and second grippping members 8, 9 may however be changed, or the size of the object to be gripped 2000 may be larger than the predetermined one, or the present robot gripper mechanism can be applied for modeling purposes, industrial use, etc., which may lead to a requirement to increase the torque of the first and second gripping electric motors 2, 3 to drive the first and second gripping members 8, 9 from the position of approaching the object to be gripped 2000 to the position of gripping the object to be gripped 2000. The use of the boost circuit is especially suitable to be able to respond well to operation of the robot gripper mechanisms in various arrangments.
In a preferred embodiment, the gripping member shaft driving assembly could use an electric motor and driving gears to drive the first and second gripping member shafts.
The first and second gripping members 8, 9 need not be made entirely of elastic material, but may be made from at least partly of elastic material, provided the elastic material part can elastically deform from the position of approaching to the position of gripping the object to be gripped.
In general, a boost circuit is a circuit that transforms an input voltage into a larger output voltage. Construction of the boost circuit may include an inductor, a semiconductor switch (for example, a MOSFET), that opens and closes at a fast rate, diodes, and a capacitor. It can be easily seen that the boost circuit has an uncomplicated structure and does not use a large number of electronic components, so the size of the boost circuit is relatively compact, capable of being arranged next to the driving circuit board, or can also be integrated or arranged into the drive board without increasing the size of the driving board significantly. Therefore, the use of the boost circuits to increase the battery voltage supplied to the step motors, servomotors or corresponding actuators used in programmable educational robots does not substantially increase the overall size of robot according to the present invention, and could eliminate the need of increasing the nominal voltage, capacity, and size of the battery pack. This is also beneficial in practical use, as commercially available batteries commonly used for programmable educational robots may not have the nominal voltage, required capacity, interchangeability of the batteries is considered not feasible without the boost circuit usage or similar solutions.
In practice, operating power ranges of the driving electric motors used in robots can be quite varied, for example the driving electric motors for robot movement may have relatively larger operating power ranges compared to that of the gripper mechanism. Therefore, more than one boost circuit can be used, wherein each of the boost circuits can be used to power one or more of the driving electric motors at a suitable operating power range.
In a specific example, the gripper mechanism of the present invention can be driven by one or two servomotors that can operate with voltages of up to 6V or 9V to increase gripping force when needed, separate boost circuit may be provided to provide power for the driving of the present gripper mechanism.
Figure 5 shows a schematic diagram of an embodiment using a boost circuit according to a preferred embodiment of the present invention.
As shown in Figure 5, the battery power supply and the power supply circuit 100 provide a power supply with a voltage according to the nominal battery voltage, for example between 3.7 and 6V, to the boost circuit 200. The circuit 200 adjusts to increase the required voltage, for example between 6 and 9V, or 12 to 18V to supply the controlling circuit 300. The controlling circuit provides power, based on a boost regulated voltage, to the driving motor 400 and controls operation of the motor 400 at the same time.
Here, the battery and power circuit 100 can represent the battery pack and the power circuit block, the motor 400 can represent the driving motors of active wheels of the programmable educational robot and/or gripping electric motors, the boost circuit 200 and the controlling circuit 300 can be components in the controlling circuit block or board.
In a specific example, the boost circuit 200 could be an available IC with the commercial designation MT3608 (IC MT3608), the controlling circuit 300 could be an available IC with the commercial designation A4988 (IC A4988), and the driving motor 400 can be either a step motor or a similarly available electric motor.
It can be easily seen from the above-mentioned specific example, only a low voltage source of about 5V (3.7 to 6V), through the boost circuit using the MT3608 IC, can drive a step motor, for example, of 28BYJ-48 type, up to speeds of 70 to 80 rpm, or even more, which essentially satisfies the speed and torque sufficient for moving the robot to perform extensive operations including more complex tasks such as ones discussed in the description of prior art above.
Electric motors to drive other mechanisms or to perform other robot functions, e.g. gripper mechanism, may also require less power than that of driving the robot. Therefore, the driving electric motors, e.g. for the gripper mechanism can use servomotors, and the boost circuit in the case of low voltage sources of about 5V (3.7 to 6V) can be used to drive the servomotor to be operated within a voltage range of up to 6V or 9V. Additionally, the servomotors each can be equipped with a motor controlling circuit. Therefore, the controlling circuit 300 according to the embodiment illustrated in Figure 5 can be omitted.
It should be understood that the present invention is not limited to specific types of motors or operating voltage ranges as described above, but they can be selected/designed in accordance with actual requirements. At the same time, driving electric motors for different purposes can be used with separate boost circuits if the power ranges are relatively different, or a shared boost circuit can be used if the power ranges are the same or are suitably similar.
The robot of the present invention can only need only a power source from a low-voltage battery, for example, 3.7V or 5V, which is a common, neat, convenient, and easy-to-find battery power source compared to other power sources from high voltage batteries (e.g. 12V), for use in both of the controlling circuit and driving motors.
Besides, the voltage supplied to the driving motor is always stable regardless of various high and low battery voltages (fully charged or almost run out of battery), which helps the robot move stably. At the same time, the advanced voltage level for the motor can be flexibly adjusted according to needs of the robot of a slower, more batterysaving configuration (reduced voltage level) or a faster, stronger, more batteryconsuming configuration (increased voltage level) without changing the battery source, but some of auxiliary components connected to the boost circuit, for example two resistors in the boost circuit. In addition, the components in the boost circuit and controlling circuit are all common and easy-to-find components.
In a preferred embodiment where the first and second gripping members 8, 9 are driven by two independent driving electric motors 2, 3, the first and second gripping members 8, 9 are not necessarily always rotated symmetrically to each other, which may deviate from their symmetrical position. Obviously, in addition to the symmetrical position, positions that are slightly out of the symmetrical one can also grip and hold the object steadily, in other words gripping and lifting the object can be performed easier and does not require a too high level of precision.
Furthermore, thanks to use of the two independently driving electric motors 2, 3, the first and second gripping members 8, 9 not only grip and hold the object fixedly, but they can be driven to “shake" the object. At this time, if one of the electric motors rotates slightly upwards, and the other rotates slightly downwards, the first and second gripping members 8, 9 will be driven to tilt the object slightly left or right. Repeating the steps will cause the object to be shaken slightly.
Figures 6A to 6C show different states that the present robot gripper mechanism 1000 grips, lifts, and shakes the object to be gripped 2000.
As shown in the figures, when the first gripping member 8 is driven upwards and the second gripping member 9 is driven downwards, which will tilt the object to be gripped 2000 to the left (or shake to the left), when the first gripping member 8 is driven downwards and the second gripping member 9 is driven upwards, which will cause the object to be gripped 2000 to the right, through the symmetrical position (see Figure 6B), and tilt to the right (or shake to the right). Then, the first and second gripping members 8, 9 are driven in the opposite direction to shake the object to be gripped 2000 from the lilted (inclined) position to the right through the symmetrical position and to the lilted position to the left. The steps can be repeated over a predetermined time or condition to meet a given requirement..
While the present invention has been described with reference to the foregoing specific details of preferred embodiments, and may be accompanied by alternative or equivalent embodiments or specific examples, using appropriate descriptions and terms so that one skilled in the art can understand and implement the present invention. Therefore, one skilled in the art can easily make equivalent changes, modifications, or substitutions based on the disclosure and embodiments as described herein. Therefore, it should be appreciated, though, that the present invention is defined by the following claims, the equivalent changes, modifications, or substitutions are not considered to depart from the inventive concepts contained herein, and the scope of the present invention is obviously not limited to the disclosure and embodiments.

Claims

What is claimed is:
1. A robot gripper mechanism includes: a first gripping member and a second gripping member are made of elastic material, in which the first and second gripping members have first and second gripping surfaces, respectively, for gripping both sides of an object grippedto be gripped, by contacting and pressing the first and second gripping surfaces against the both sides of the object; a first gripping member shaft for mounting the first gripping member and a second gripping member shaft for mounting the second gripping member; a mounting bracket for mounting and rotationally supporting the first and second gripping member shafts thereon; a gripping member shaft driving assembly to rotationally drive the first and second gripping member shafts around axes along with axial directions of the first and second gripping member shafts respectively; in which: the first gripping member shaft and the second gripping member shaft are arranged basically parallel to each other and kept in a fixed position during operation; the first and second gripping members are arranged to protrude from the first and second gripping member shafts respectively, with the first and second gripping surfaces protruding the furthest from the first and second gripping member shafts, such that when the first and second gripping members, rotated around the first and second gripping member shafts, reach a gripping position, the first and second gripping surfaces are opposite to each other and at the closest distance between the first and second gripping member shafts, when the first and second gripping members rotated around the first and second gripping member shafts, come out of the gripping position, the first and the second gripping surfaces move away from each other, characterized in that: the first and second gripping members are constructed so that when the first and second gripping members rotate from a gripping release position to a gripping position, they will come into contact with the object to be gripped, elastically deformed to gradually press the object to be gripped, and at the gripping position, the first and second gripping surfaces are pressed against the both sides of the object so that the object elastically deforms and presses the first and second gripping members towards the first and second gripping member shafts, respectively, thereby producing elastic forces tightly pressing to the both sides of the object to be gripped for gripping the object, wherein, at the gripping position, the said elastic forces are directed through the rotational axes of the first and second gripping member shafts such that the elastic forces do not produce a torque acting on the first and second gripping member shafts, whereby when reaching the gripping position, the first and second gripping member shafts are left free and do not need to maintain a force driven by the gripping member shaft driving assembly, while still maintain a stable gripping state of the object to be gripped, based on the elastic forces and relative positions of the first and second gripping members, the first and second gripping member shafts, and the object to be gripped.
2. The robot gripper mechanism of claim 1 , in which the gripping member shaft driving assembly includes a first gripping electric motor to drive the first gripping member shaft and a second gripping electric motor to drive the limb second gripping member shaft.
3. The robot gripper mechanism of claim 2, in which the mounting bracket includes a mounting plate for mounting the first and second gripping electric motors, and axes of the first and second gripping electric motors serve as the first and second gripping member shafts.
4. The robot gripper mechanism of claim 3, in which the first and second gripping members are mounted on the first and second gripping member shafts using first and second mounting bars respectively, in which the first and second gripping members are constructed with mounting slots for inserting the first and second mounting bars, respectively, the first and second mounting bars are constructed with mounting holes for inserting the motor axes of the first and second gripping electric motors, respectively.
5. The robot gripper mechanism of claims 2, 3, or 4, in which the first and second gripping electric motors are mounted on the mounting plate using a flexible tie.
6. The robot gripper mechanism of any of claims 1 to 5, in which the first and second gripping members are in an approximate V-shape, in which the V pointed end parts are mounted on the first and second gripping member shafts, and the two V not-pointed end parts face towards the object gripped to be gripped and form the first and second gripping surfaces, respectively.
7. The robot gripper mechanism of claim 6, in which the first and second gripping members are driven to rotate in opposite directions, so that both the first and second gripping members tend to lift the object to be gripped while moving from the gripping release position to the grip position.
8. The robot gripper mechanism of any of claims 2 to 7, in which the robot gripper mechanism is made suitable for use for programmable educational robot cars, model robots, industrial robots, or the like, and the first and second gripping electric motors are powered by a battery pack located on the programmable educational robot car through a DC-DC boost converter circuit to increase the voltage supplied to the first and second gripping electric motors, by which increasing their maximum torque when gripping the object to be gripped without increasing the nominal voltage, capacity, and size of the battery pack.
PCT/VN2023/000003 2022-03-02 2023-03-02 A robot gripper mechanism WO2023168465A2 (en)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
VN1-2022-01315 2022-03-02
VN1202201315 2022-03-02
VN1202203513 2022-06-03
VN1-2022-03513 2022-06-03

Publications (2)

Publication Number Publication Date
WO2023168465A2 true WO2023168465A2 (en) 2023-09-07
WO2023168465A3 WO2023168465A3 (en) 2023-12-07

Family

ID=87884410

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/VN2023/000003 WO2023168465A2 (en) 2022-03-02 2023-03-02 A robot gripper mechanism

Country Status (1)

Country Link
WO (1) WO2023168465A2 (en)

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10259122B2 (en) * 2015-03-05 2019-04-16 President And Fellows Of Harvard College Compliant adaptive robot grasper
US9808936B2 (en) * 2015-08-03 2017-11-07 Massachusetts Institute Of Technology Two-phase gripper to reorient and grasp
CN110421591B (en) * 2019-09-05 2023-06-27 成都易爪机器人科技有限公司 Passive finger and two-finger mechanical claw using same
CN112008751B (en) * 2020-08-19 2021-12-03 西伯瀚(泰兴)传动技术有限公司 Mechanical gripper at tail end of mechanical arm

Also Published As

Publication number Publication date
WO2023168465A3 (en) 2023-12-07

Similar Documents

Publication Publication Date Title
Stasse et al. TALOS: A new humanoid research platform targeted for industrial applications
Davey et al. Emulating self-reconfigurable robots-design of the SMORES system
US9174338B2 (en) Robotic movement system
Ott et al. Development of a biped robot with torque controlled joints
Wright et al. Design and architecture of the unified modular snake robot
JP2005161469A (en) Robot device and overcurrent protective device for robot device
CN101670581A (en) Robot hand and humanoid robot having the same
Malley et al. Flippy: A soft, autonomous climber with simple sensing and control
CN104802180B (en) Drive lacking anthropomorphic three refers to manipulator
Goris Autonomous mobile robot mechanical design
CN109676598B (en) Modular robot of autonomic equipment
Kim et al. Snapbot: A reconfigurable legged robot
Tagliamonte et al. Design of a variable impedance differential actuator for wearable robotics applications
CN208788595U (en) A kind of vision positioning robot
US5157316A (en) Robotic joint movement device
US20110071673A1 (en) Actuator and electronics packaging for extrinsic humanoid hand
CN106903710B (en) Humanoid dexterous hand base joint mechanism
WO2023168465A2 (en) A robot gripper mechanism
Ozaki et al. Takeoff of a 2.1 g fully untethered tailless flapping-wing micro aerial vehicle with integrated battery
JP4289447B2 (en) Robot device and joint axis drive device
Govindan et al. Graspman-a novel robotic platform with grasping, manipulation, and multimodal locomotion capability
CN110524510A (en) A kind of cube one-wheel robot
Ai et al. Design and control of a cable-driven series elastic actuator for exoskeleton
CN201357412Y (en) Multi-control mode manipulator
Bonci et al. Embedded system for a Ballbot robot