Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
  • B25J—MANIPULATORS; CHAMBERS PROVIDED WITH MANIPULATION DEVICES
  • B25J9/00—Programme-controlled manipulators
  • B25J9/003—Programme-controlled manipulators having parallel kinematics
  • B25J9/0045—Programme-controlled manipulators having parallel kinematics with kinematics chains having a rotary joint at the base
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23Q—DETAILS, COMPONENTS, OR ACCESSORIES FOR MACHINE TOOLS, e.g. ARRANGEMENTS FOR COPYING OR CONTROLLING; MACHINE TOOLS IN GENERAL CHARACTERISED BY THE CONSTRUCTION OF PARTICULAR DETAILS OR COMPONENTS; COMBINATIONS OR ASSOCIATIONS OF METAL-WORKING MACHINES, NOT DIRECTED TO A PARTICULAR RESULT
  • B23Q1/00—Members which are comprised in the general build-up of a form of machine, particularly relatively large fixed members
  • B23Q1/25—Movable or adjustable work or tool supports
  • B23Q1/26—Movable or adjustable work or tool supports characterised by constructional features relating to the co-operation of relatively movable members; Means for preventing relative movement of such members
  • B23Q1/32—Relative movement obtained by co-operating spherical surfaces, e.g. ball-and-socket joints
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23Q—DETAILS, COMPONENTS, OR ACCESSORIES FOR MACHINE TOOLS, e.g. ARRANGEMENTS FOR COPYING OR CONTROLLING; MACHINE TOOLS IN GENERAL CHARACTERISED BY THE CONSTRUCTION OF PARTICULAR DETAILS OR COMPONENTS; COMBINATIONS OR ASSOCIATIONS OF METAL-WORKING MACHINES, NOT DIRECTED TO A PARTICULAR RESULT
  • B23Q1/00—Members which are comprised in the general build-up of a form of machine, particularly relatively large fixed members
  • B23Q1/25—Movable or adjustable work or tool supports
  • B23Q1/44—Movable or adjustable work or tool supports using particular mechanisms
  • B23Q1/48—Movable or adjustable work or tool supports using particular mechanisms with sliding pairs and rotating pairs
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23Q—DETAILS, COMPONENTS, OR ACCESSORIES FOR MACHINE TOOLS, e.g. ARRANGEMENTS FOR COPYING OR CONTROLLING; MACHINE TOOLS IN GENERAL CHARACTERISED BY THE CONSTRUCTION OF PARTICULAR DETAILS OR COMPONENTS; COMBINATIONS OR ASSOCIATIONS OF METAL-WORKING MACHINES, NOT DIRECTED TO A PARTICULAR RESULT
  • B23Q1/00—Members which are comprised in the general build-up of a form of machine, particularly relatively large fixed members
  • B23Q1/25—Movable or adjustable work or tool supports
  • B23Q1/44—Movable or adjustable work or tool supports using particular mechanisms
  • B23Q1/50—Movable or adjustable work or tool supports using particular mechanisms with rotating pairs only, the rotating pairs being the first two elements of the mechanism
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23Q—DETAILS, COMPONENTS, OR ACCESSORIES FOR MACHINE TOOLS, e.g. ARRANGEMENTS FOR COPYING OR CONTROLLING; MACHINE TOOLS IN GENERAL CHARACTERISED BY THE CONSTRUCTION OF PARTICULAR DETAILS OR COMPONENTS; COMBINATIONS OR ASSOCIATIONS OF METAL-WORKING MACHINES, NOT DIRECTED TO A PARTICULAR RESULT
  • B23Q16/00—Equipment for precise positioning of tool or work into particular locations not otherwise provided for
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
  • B25J—MANIPULATORS; CHAMBERS PROVIDED WITH MANIPULATION DEVICES
  • B25J9/00—Programme-controlled manipulators
  • B25J9/003—Programme-controlled manipulators having parallel kinematics
  • B25J9/0072—Programme-controlled manipulators having parallel kinematics of the hybrid type, i.e. having different kinematics chains
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
  • B25J—MANIPULATORS; CHAMBERS PROVIDED WITH MANIPULATION DEVICES
  • B25J9/00—Programme-controlled manipulators
  • B25J9/02—Programme-controlled manipulators characterised by movement of the arms, e.g. cartesian coordinate type
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
  • F16C11/00—Pivots; Pivotal connections
  • F16C11/04—Pivotal connections
  • F16C11/06—Ball-joints; Other joints having more than one degree of angular freedom, i.e. universal joints
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16M—FRAMES, CASINGS OR BEDS OF ENGINES, MACHINES OR APPARATUS, NOT SPECIFIC TO ENGINES, MACHINES OR APPARATUS PROVIDED FOR ELSEWHERE; STANDS; SUPPORTS
  • F16M11/00—Stands or trestles as supports for apparatus or articles placed thereon ; Stands for scientific apparatus such as gravitational force meters
  • F16M11/02—Heads
  • F16M11/04—Means for attachment of apparatus; Means allowing adjustment of the apparatus relatively to the stand
  • F16M11/06—Means for attachment of apparatus; Means allowing adjustment of the apparatus relatively to the stand allowing pivoting
  • F16M11/12—Means for attachment of apparatus; Means allowing adjustment of the apparatus relatively to the stand allowing pivoting in more than one direction
  • F16M11/14—Means for attachment of apparatus; Means allowing adjustment of the apparatus relatively to the stand allowing pivoting in more than one direction with ball-joint
• • G—PHYSICS
  • G05—CONTROLLING; REGULATING
  • G05D—SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
  • G05D3/00—Control of position or direction

Definitions

• the invention involves a device for control of a spherical motion of a body connected with a frame through a spherical joint arranged on a shank connecting the body with the frame, where the shank is three-sectional and the spherical joint with at least two rotational degrees of freedom is arranged between the first part of the shank, which is firmly fixed to the frame, and the second part of the shank, which is firmly fixed to the body, and by means of actuating arms connected rotationally to the frame and the body.
• the controlled spherical motion of a body is important in many applications, for example for tilting heads of machining devices or for adjusting positions of telescopes and antennas.
• Such a movement is performed today either through mechanisms with a series kinematic structure, mostly based on gimbal, or mechanisms with a parallel kinematic structure.
• Mechanisms with a series kinematic structure have a large moveability, thereupon a range of 180 degrees in two rotations, but they are mass, their dynamic capabilities are low and they do not allow a continuous movement from one position to another in all positions.
• mechanisms with a parallel kinematic structure have a limited moveability, thereupon a range less than 90° in two rotations usually, but they feature substantially lower weight, have higher dynamic capabilities and they enable a continuous movement from all positions to all the subsequent positions.
• Octapod An alternative mechanism with a parallel kinematic structure, which enables to reach a platform tilting angles range up to 90° is Octapod (Valasek, M., Sika, Z., Bauma, V., Vampola, T.: The innovative Potential of Redundantly Actuated PKM, In: Neugebauer, R.: Proc. of Parallel Kinematics Seminar 2004, IWU FhG, Chemnitz 2004, pp. 365-384) and Metrom (Schwaar, M., Jaehnert, T., Ihlenfeldt, S.: Mechatronic Design, Experimental Property Analysis and Machining Strategies for a 5-Strut-PKM, In: Neugebauer, R.: Proc. of Parallel Kinematics Seminar 2002, IWU FhG, Chemnitz 2002, pp. 671-681).
• a disadvantage of Octapod is that arms are positioned all around the platform.
• Metrom is lowered manipulability near extreme positions.
• TetraSphere a mechanism has been proposed in CZ306555 patent (called TetraSphere), reaching the motion range more than 90 degrees, and having only four actuators with a special control, thus achieving better manipulability than EcoSphere, however, not as good as HexaSphere. All of these solutions have either four and more actuators or do not reach as good manipulability as HexaSphere.
• DoubleSphere a mechanism has been proposed in CZ306965 patent (called DoubleSphere), reaching the motion range more than 90 degrees, and having three actuators only, thus achieving better manipulability than EcoSphere, however, not as good as HexaSphere. Its disadvantage is that the constructional space for this mechanism is larger in a case of an actuator realized through a motion along the frame.
• the aim of this invention is a device for a controlled spherical motion of bodies on the basis of mechanisms with a parallel kinematic structure, which would achieve a moveability consonant to mechanisms with a series kinematic structure, thereupon a range up to 200 degrees in two rotations while preserving all advantages of mechanisms with a parallel kinematic structure, whereas requiring a lower number of actuators in comparison with similar mechanisms, reaching a similar manipulability and demanding a smaller constructional space.
• another goal of this invention is to achieve higher accuracy of adjusting the body’s positions.
• the rotational joints and/or rotary actuators by means of which three actuating arms are connected to the frame, in a projection contain 120° angle around the shank axis.
• the first part of the shank has possibly a variable length due to the linear actuator with which the first part of the shank is fitted.
• Fig. 1 shows a schematic depiction of one of possible embodiments
• Fig. 2 shows a vertical projection of the device as depicted in Fig. 1
• Fig. 3 shows another variant of the embodiment as depicted in Fig. 1
• Fig. 4 shows another variant of the embodiment as depicted in Fig. 1
• Fig. 5 shows an arm of the device fitted with a rotational j oint
• Fig. 6 shows another variant of the embodiment as depicted in Fig. 1 with a variable length of the shank
• Fig. 1 shows a schematic depiction of a variant of the embodiment according to the invention.
• platform-body 1_ is connected to frame 5 by means of three parts 7, 8, 1_3 of the shank, whereas one end of the first part 7 of the shank is firmly fixed to frame 5 and the second end of the first part 7 of the shank is connected through spherical joint 2 to inserted part 13 of the shank, one end of which is connected to the first part 7 of the shank and the second end of which is connected through spherical joint 12 to the second part 8 of the shank that is firmly fixed to body L
• Platform-body 1 carries machining tool 120, the axis of which is perpendicular to platform-body ⁇ and passes through its centre.
• first part 7 of the shank may possibly form one component together with frame 5 and the second end of the second part 8 of the shank may form one component with body L
• Both parts 7, 8 of the shank are connected together through inserted part F3 by spherical joints 2 and 12, which enables the body‘s 1 motion towards frame 5. All three parts 7, 8, 1_3 of the shank have non-zero lengths.
• Body I and frame 5 are connected together by three various ways. These three ways are depicted in Figs. 1, 3 and 4. A variant depicted in Fig.
• Telescopic actuators F4 are designed e.g. as hollow shafts or telescopic ball screws actuated by a rotary or linear electric actuator, or as hydraulic or pneumatic cylinders.
• Spherical joints 2, 12, 10 consist of joints with at least two rotational degrees of freedom.
• the number of parallel arms 3 with actuators 4 is three and is redundant, which means that the number of actuators of parallel actuating arms 3 is three and is higher than the number of degrees of freedom of body 1 determined by two rotations for setting-up of the direction of body I in two degrees of freedom of e.g. a direction of the axis of machining tool 120. By this, singular positions are excluded from the working area of the spherical motion of body 1.
• Fig. 2 shows a vertical projection of the device depicted in Fig. 1 in a direction of the axis of shank 7.
• Rotational joints 6 are typically positioned on a surface of the cylinder or along a circle around the axis of shank 7.
• rotational joints 6 are positioned symmetrically in 120 degrees. This is a depiction of the device position where all parts 7, 8, F3 of the shank are in one axis.
• Fig. 1 where rotational joints 6 of arms 3 are arranged symmetrically around spherical joint 2, which means that projections of rotational joints 6 and arms 3 mutually contain angles of 120 degrees and that rotational joints 6 in Fig.
• Arms 3 are connected to body J_ through spherical joints K) on outer shanks 9, which are arranged along platform -body I of a circular shape symmetrically in 120 degrees.
• the axis of tool 120 passes through the centre of this circle and is perpendicular to the plane formed by centres of spherical joints 10. Outer shanks 9 favourably prevent a collision between arms 3 and body I when moving, but they are not necessary for the solution.
• Parallel actuating arms 3 are connected to linear actuators 4 through rotational joints 6.
• a controlled spherical motion of body 1, given by the setting-up of the direction of body I, is achieved by a change in positions of linear actuators 4 in the guides on frame 5, leading to a change in positions of rotational joints 6 of arms 3.
• the spherical motion of body ⁇ originates from a change of three rotations of body which can be described by an azimuth, elevation and very rotation, or the setting-up of the direction of body 1 is created by a change of only two rotations of body I, which can be described by an azimuth and elevation.
• the azimuth is a rotation of body I around the axis of machining tool 120.
• the elevation is a change in an angle of the axis of machining tool 120 (usually towards the axis of the first part 7 of the shank) and the very rotation is a turning of body ! around the axis of machining tool 120 in the resulting position given by the previous turning of the azimuth and elevation.
• all of these rotations are performed at the same time.
• only a rotation of the axis of machining tool 120 to the required direction is often sufficient, which is determined by using only two first rotations of the azimuth and elevation.
• actuating arms 3 can be arranged asymmetrically, which means that in Fig. 2 the projections of arms 3 contain angles different from 120 degrees or that rotational joints 6 are not positioned along the circle around the projection of spherical joint 2 or that spherical joints H) are not positioned along the circle around the projection of spherical joint 2 or that rotational joints 6 are not positioned on the cylindrical area created by the first part 7 of the shank.
• machining tool 120 is attached to platform-body 1 asymmetrically.
• a great advantage of the described arrangement is that a motion of platform-body 1 is possible in two rotations within a range up to 200 degrees of elevation, while preserving all advantages of mechanisms with a parallel kinematic structure using three actuators only.
• the achieved moveability is large and a satisfactory distance from singular positions within the entire working area is achieved, leading also to a favourable transmission of forces between machining tool 120 and actuators 4_and to an increase in accuracy of positioning of tool 120.
• This is a great progress in comparison to previous solutions, where five to six actuators were needed or a motion was not possible within such a large range even with four actuators or was very limited with three actuators.
• the use of the sectional shank consisting of three parts 7, 8, 13 enables a rotation of body ! by more than 90°.
• the length of the first part 7 of the shank fixed to frame 5 should be longer than a distance of the edge of body i from a point where the second part 8 of the shank is fixed to body 1.
• a varied angle range of the rotation over 90° of body 1 can be achieved and collisions of body 1_ with parts 7, 13 of the shank can be prevented.
• Outer shanks 9 have a similar function to prevent a collision of platform-body 1 and arms 3 during their relative motion.
• a benefit of the non-zero lengths of the shank parts is a limitation of a deviation of body 1 from the axis of part 7 of the shank.
• Actuators can be added, thus increasing a redundancy of actuators and improving manipulability at the same time.
• an advantage of the solutions described herein is that in order to achieve a certain level of manipulability a lower degree of redundancy of actuators is needed, i.e. how many more actuators than degrees of freedom.
• an advantage of the described device is that the constructional space is limited by a plane defined by the centres of rotational joints 6, below which the actuators of arms 3 do not move unlike in CZ306965.
• the constructional space of the described device is only limited to the cylinder determined by the centres of rotational joints 6, the axis of part 7 of the shank, a plane of rotational joints 6 and a parallel plane passing through spherical joint 2.
• Fig. 3 shows a modified variant from Fig. 1, where telescopic actuators 14 are replaced by linear actuators 4 of arms 3.
• Linear actuators 4 can be designed e.g. as pass-through actuators - a nut with a motion screw or a rack with a rotary electric actuator or a guide with a linear electric actuator.
• Fig. 4 shows a modified variant from Fig. 1, whereas arms 3 with variable lengths realized through telescopic actuators F4 are replaced by parallel actuating arms 3, which are fitted with rotary actuators 15 for rotary motion of actuating arms 3.
• parallel actuating arms 3 are attached to spherical joints 10 for connecting to platform-body L
• These parallel actuating arms 3 have constant lengths and they are three, driven by rotary actuators 15 rotating.
• An example of rotary actuators J_5 are rotary electric actuators.
• FIG. 4 A possible alternative of the variant depicted in Fig. 4 is an interchange of rotational joints with actuator 15 and without actuator 6 on one or more actuating arms 3.
• this solution has an advantage of a limited constructional space above the plane of rotary actuators 15 having only three actuating arms with actuators.
• the use of only three actuating arms is enabled by using rotational joints 6_between actuating arms 3 and rotational arm 16 and two spherical joints 2 and 12 in the sectional shank.
• an advantage of the solution with outer shanks 9 is a prevention of collisions during the relative motion of platform-body 1 and rotational arms 16.
• Fig. 5 shows in more details rotary actuator 15 with actuating arm 3 and rotational arm 16 as depicted in Fig. 4.
• Rotary actuator F5 typically consisting of a rotary electric motor with admeasurement of the angular position and possibly with a gearbox, is attached to frame 5. It moves by actuating arm 3, which is in Fig. 5 firmly fixed to the shaft of rotary actuator 15 and is connected through rotational joint 6 to rotational arm J_6 *
• rotational arm 16 is attached to platform-body 1 through spherical joint JJ) and outer shank 9.
• Fig. 6 shows a variant as depicted in Fig. 1, where the first part 7 of the shank has a variable length by means of linear actuator G7, with which the first part 7 of the shank is fitted. This enables, aside from tilting, also extension of tool 120 with body L
• a basic advantage of the described embodiment is a demand for a smaller constructional space for the design of the device for control of a spherical motion of a body.
• a benefit of the non-zero lengths of the shank parts is a limitation of a deviation of body 1 from the axis of part 7 of the shank.
• the described variants may be combined with each other. Especially, types of actuators and types of actuating arms can be interchanged. If a parallelism or perpendicularity or an angle of axes or planes is given, then this condition is realized through the manufacture of the device and this manufacturing realization of the accurate condition of parallelism or perpendicularity is always met only within manufacturing tolerances.

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• General Physics & Mathematics (AREA)
• Automation & Control Theory (AREA)
• Manipulator (AREA)
• Transmission Devices (AREA)

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• 2018
  • 2018-12-17 CZ CZ2018-705A patent/CZ2018705A3/cs unknown
• 2019
  • 2019-02-19 WO PCT/CZ2019/000011 patent/WO2020125821A1/en unknown
  • 2019-02-19 EP EP19713343.2A patent/EP3911477A1/en active Pending

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