Series-parallel seven-degree-of-freedom force feedback mechanism

Abstract

The invention discloses a series-parallel seven-degree-of-freedom force feedback mechanism, and relates to the technical field of virtual reality force sense interaction.The series-parallel seven-degree-of-freedom force feedback mechanism comprises a series-parallel seven-free mechanical arm, a base and a driving device.The series-parallel seven-free mechanical arm comprises a rotary table, a closed-loop connecting rod mechanism, a sliding rod mechanism and a tail end executing mechanism, and the tail end executing mechanism is connected with the sliding rod mechanism; the sliding rod mechanism is connected with the closed-loop connecting rod mechanism, the closed-loop connecting rod mechanism is connected with the rotary table, the rotary table is installed on the base through a rotating pair, and the base is connected with the driving device. The series-parallel seven-degree-of-freedom force feedback mechanism is compact in structure and light in size, and has adjustable working space and force sensing range, better rigidity and higher movement flexibility by adopting a mode of series-parallel connection of a closed-loop mechanism and a series mechanism.

Description

Technical Field

[0001] The present invention relates to the technical field of virtual reality force interaction, and in particular to a hybrid seven-degree-of-freedom force feedback mechanism. Background Art

[0002] With the development of virtual reality and augmented reality technologies, force interaction technology can greatly enhance the user's sense of immersion and reality in the virtual environment and improve the quality of user experience. Force feedback technology is being widely used in game entertainment, education, medical treatment and other fields, and has broad application prospects.

[0003] At present, there are two mainstream structures of existing force feedback devices: force feedback devices with a series structure as the main one have high movement flexibility and a large movement space, but their mechanical rigidity is poor and it is difficult to achieve a large feedback force output; force feedback devices with a parallel structure as the main one have good rigidity and can achieve a large feedback force output, but their movement space is small and their flexibility is poor.

[0004] Therefore, the hybrid force feedback device with compact structure, light volume, large working space, high flexibility and taking into account both mechanical stiffness and output force has broad application prospects. Summary of the invention

[0005] The purpose of the present invention is to provide a hybrid seven-degree-of-freedom force feedback mechanism, which has a small overall volume, a compact structure, good mechanical rigidity and high movement flexibility, and is suitable for realizing spatial three-dimensional force feedback output in the field of force interaction.

[0006] To achieve the above-mentioned purpose, the present invention provides a hybrid seven-degree-of-freedom force feedback mechanism, including a hybrid seven-degree-of-freedom mechanical arm, a base and a driving device, the hybrid seven-degree-of-freedom mechanical arm includes a turntable, a closed-loop connecting rod mechanism, a sliding rod mechanism and an end actuator, the end actuator is connected to the sliding rod mechanism, the sliding rod mechanism is connected to the closed-loop connecting rod mechanism, the closed-loop connecting rod mechanism is connected to the turntable, the turntable is mounted on the base through a rotating pair, and the base is connected to the driving device.

[0007] Preferably, the closed-loop connecting rod mechanism comprises an upper long rod, a lower short rod, a lower long rod and an end rod, and the end rod is provided with two hinges, namely a middle hinge and an upper hinge, one end of the upper hinge is connected to one end of the upper long rod, the other end of the upper long rod is hinged to the turntable through the rotating pair, the turntable is hingedly connected to one end of the lower short rod through the rotating pair, the other end of the lower short rod is connected to the lower long rod through the rotating pair, the other end of the lower long rod is hinged to the middle hinge, and the lower part of the end rod is connected to the sliding rod mechanism.

[0008] Preferably, the sliding rod mechanism includes a sliding rod, a locking knob and a position sensor, the position sensor is arranged on the upper part of the sliding rod, the sliding rod is slidingly connected to the end rod through a moving pair, a notch is provided at the lower part of the end rod, the notch is connected to the locking knob, the locking knob locks the relative position of the sliding rod, and the end of the sliding rod is connected to the end actuator.

[0009] Preferably, the end actuator includes an end handle, a first rotating shaft and a second rotating shaft. The second rotating shaft and the end handle, the second rotating shaft and the first rotating shaft are all connected through the rotating pair. The first rotating shaft is connected to the lower end of the sliding rod through the rotating pair. The three rotating pairs are perpendicular to each other.

[0010] Preferably, the driving device includes a first driving motor, a second driving motor, a third driving motor, a first driven wheel and a second driven wheel, the second driven wheel is connected to the third driving motor, the third driving motor and the second driving motor are both fixed on the supporting structure of the turntable and arranged in parallel behind the closed-loop connecting rod mechanism.

[0011] Preferably, the second driving motor drives the first driven wheel by wire transmission, and the first driving motor is fixed on the base to drive the turntable to rotate.

[0012] Preferably, the first driven wheel is fixedly connected to the lower short rod, the second driven wheel is fixedly connected to the upper long rod, and the hinges of the upper long rod and the turntable and the turntable and the lower short rod are arranged in parallel in the vertical direction to form a planar five-bar mechanism with two degrees of freedom.

[0013] Preferably, a counterweight structure is provided on both the first driven wheel and the second driven wheel for balancing the deadweight of the closed-loop connecting rod mechanism.

[0014] Preferably, rotary encoders are installed at the rotating pair connections of the end actuator, and the first drive motor, the second drive motor and the third drive motor are equipped with motor encoders, which are combined with the position sensor in the slide bar mechanism to realize real-time posture calculation of the end handle.

[0015] Preferably, the base, the first driven wheel and the second driven wheel are provided with limiting grooves, and the turntable is respectively provided with three limiting columns that are slidably matched with the limiting grooves.

[0016] Therefore, the present invention adopts the above-mentioned hybrid seven-degree-of-freedom force feedback mechanism, which has the following beneficial effects: (1) The driving mechanism of the present invention is cleverly integrated on the rear side of the main structure, with a compact structure, small size, light weight, and easy layout and installation.

[0017] (2) The present invention adopts a hybrid structural design, especially the use of an asymmetric closed-loop connecting rod mechanism, which ensures good mechanical stiffness while taking into account both movement space and high flexibility, and can achieve a large force feedback output.

[0018] (3) The present invention uses a sliding rod mechanism to add a redundant degree of freedom to the robot arm, thereby achieving adjustable range of the robot arm's operating space and force feedback output, and improving adaptability to the requirements of different application scenarios.

[0019] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a forward axial side view of the present invention; Figure 2 This is a structural diagram of the hybrid mechanical arm of the present invention; Figure 3 It is a schematic diagram of the structure of the slide bar mechanism of the present invention; Figure 4 It is a cross-sectional view of the slide bar mechanism of the present invention; Figure 5 It is a schematic diagram of the structure of the driving device of the present invention; Figure 6 It is a schematic diagram of the turntable and base structure of the present invention; Reference numerals 1. Robotic arm; 11. Turntable; 111. Limit column; 12. Closed-loop connecting rod mechanism; 121. Upper long rod; 122. Lower short rod; 123. Lower long rod; 124. End rod; 13. Sliding rod mechanism; 131. Sliding rod; 132. Locking knob; 133. Position sensor; 14. End actuator; 141. End handle; 142. First rotating shaft; 143. Second rotating shaft; 2. Base; 3. Driving device; 31. First driving motor; 32. Second driving motor; 33. Third driving motor; 34. First driven wheel; 35. Second driven wheel. DETAILED DESCRIPTION

[0021] The technical solution of the present invention is further described below through the accompanying drawings and embodiments.

[0022] Unless otherwise defined, the technical terms or scientific terms used in the present invention should be understood by people with ordinary skills in the field to which the present invention belongs. The words "first", "second" and similar words used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. "Include" or "comprise" and similar words mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0023] Example See also Figure 1-6 The present invention provides a hybrid seven-degree-of-freedom force feedback mechanism, including a hybrid seven-degree-of-freedom mechanical arm 1, a base 2 and a driving device 3, such as Figure 1 and Figure 2 As shown, the hybrid seven-degree-of-freedom robot 1 includes a turntable 11, a closed-loop connecting rod mechanism 12, a sliding rod mechanism 13 and an end actuator 14; the turntable 11 is installed on the base 2 through a rotating pair, and a supporting structure for fixing and supporting the robot arm 1 and a driving device 3 is provided thereon, which can drive the robot arm 1 to rotate around a vertical axis; the closed-loop connecting rod mechanism 12 has two degrees of freedom and is connected to the turntable 11 through two rotating pairs; the sliding rod mechanism 13 is located at the end of the closed-loop connecting rod mechanism 12, and the extension amount of the sliding rod mechanism 13 is adjusted and locked, so as to realize the adjustment of the operating space and operating force range of the robot arm 1.

[0024] The closed-loop connecting rod mechanism 12 includes an upper long rod 121, a lower short rod 122, a lower long rod 123 and an end rod 124. One end of the upper long rod 121 is hinged to the supporting structure of the turntable 11 through a revolving pair, and the other end is connected to the upper hinge point of the end rod 124 through a revolving pair; the lower short rod 122 is hinged to the supporting structure of the turntable 11 through a revolving pair, and the other end is connected to the lower long rod 123 through a revolving pair, and the other end of the lower long rod 123 is hinged to the middle hinge point of the end rod 124; the two hinge points of the supporting structure on the turntable 11 are arranged in parallel in the vertical direction, and the above constitutes a planar five-bar mechanism with two degrees of freedom.

[0025] The closed-loop linkage mechanism 12 adopts an asymmetric closed-loop topology and has a smaller spatial structure while taking into account a larger activity space and higher movement flexibility. Combined with the rotational movement of the turntable 11, the covered activity space can meet the use scenarios of most force interaction.

[0026] like Figure 3 As shown, the sliding rod mechanism 13 includes a sliding rod 131, a locking knob 132 and a position sensor 133. The sliding rod 131 is slidingly connected to the end rod 124. A slot is provided on the end rod 124. The locking knob 132 passes through the slot and is threadedly connected to the sliding rod 131. By tightening or loosening the locking knob 132, the sliding rod 131 can be locked and unlocked relative to the end rod 124. The position sensor 133 can read the position information of the sliding rod 131.

[0027] The end actuator 14 includes an end handle 141, a first rotating shaft 142 and a second rotating shaft 143. The first rotating shaft 142 is installed on the lower end of the sliding rod 131 through a rotating pair. The first rotating shaft 142 and the second rotating shaft 143 and the second rotating shaft 143 and the end handle 141 are all connected through a rotating pair. The axes of the three rotating pairs are perpendicular to each other, forming a three-degree-of-freedom series end actuator.

[0028] The hybrid manipulator 1 is composed of a turntable 11, a closed-loop connecting rod mechanism 12, a sliding rod mechanism 13 and an end actuator 14, and has seven degrees of freedom in space. The sliding rod mechanism 13 can be adjusted to adjust the operating space and force feedback range of the manipulator 1: increasing its extension can obtain a larger operating space and a smaller force feedback output; reducing its extension can obtain a larger force feedback output and a smaller operating space, and then the appropriate operating space can be adjusted according to different scene requirements and the corresponding operating force feedback can be matched. The combination of series mechanism and parallel mechanism ensures high flexibility of end movement while having high position accuracy and good mechanical stiffness, which fully meets the work requirements in the field of force interaction.

[0029] like Figure 1 and Figure 4As shown, the driving device 3 is installed at the rear side of the main structure, and adopts servo motor drive and wire transmission. The three motors drive the turntable 11 and the two driving shafts of the closed-loop connecting rod mechanism 12 respectively, and provide three-dimensional force feedback output for the end handle 141. The driving device 3 includes a first driving motor 31, a second driving motor 32, a third driving motor 33, a first driven wheel 34 and a second driven wheel 35; the first driving motor 31 is fixed on the base 2, and drives the turntable 11 to rotate through the wire transmission, thereby driving the hybrid robot arm 1 to rotate around the vertical axis; the second driving motor 32 The first and second driven wheels 34 and 35 are respectively arranged on both sides of the support structure of the turntable 11; the second and third driving motors 32 and 33 drive the first and second driven wheels 34 and 35 to rotate respectively through wire transmission, the first driven wheel 34 is fixedly connected to the lower short rod 122 through a rotating shaft, and the second driven wheel 35 is fixedly connected to the upper long rod 121 through a rotating shaft, thereby realizing the driving of the two-degree-of-freedom closed-loop linkage mechanism 12. Therefore, the hybrid seven-degree-of-freedom manipulator 1 can realize the three-dimensional force feedback output of the end handle 141 through three driving motors.

[0030] like Figure 1 and Figure 5 As shown, the base 2, the first driven wheel 34 and the second driven wheel 35 are provided with arc-shaped limiting grooves, and the turntable 11 is respectively provided with three limiting posts 111 cooperating therewith, and the limiting posts 111 are slidably connected with the grooves. At the same time, the first rotating shaft 142 and the second rotating shaft 143 can be angle-limited by a mechanical housing to prevent the hybrid seven-degree-of-freedom robot arm from exceeding its working space; Figure 1 and Figure 3 As shown, the first driven wheel 34 and the second driven wheel 35 are provided with a fan-shaped counterweight structure, which can balance the deadweight of the closed-loop connecting rod mechanism 12, thereby obtaining a more accurate force feedback output.

[0031] Rotary encoders are installed at the three rotating joints of the end actuator 14, and the first drive motor 31, the second drive motor 32 and the third drive motor 33 of the drive device 3 are all equipped with motor encoders. Combined with the measurement values ​​of the seven encoders of the position sensor 133 in the slide mechanism 13 and the model parameters of the hybrid mechanism, the real-time posture calculation of the end handle 141 can be realized, and then three-dimensional force feedback output can be achieved through the three drive motors.

[0032] Therefore, the present invention adopts the above-mentioned hybrid seven-degree-of-freedom force feedback mechanism. The driving mechanism of the present invention is cleverly integrated on the rear side of the main structure, with a compact structure, small size, light weight, and easy layout and installation. The present invention adopts a hybrid structural design, especially the use of an asymmetric closed-loop connecting rod mechanism, which ensures good mechanical rigidity while taking into account both motion space and high flexibility, and can achieve a larger force feedback output. The present invention uses a sliding rod mechanism to add a redundant degree of freedom to the robot arm, realizing the adjustable range of the robot arm's operating space and force feedback output, and improving the adaptability to the needs of different application scenarios.

[0033] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A hybrid seven-degree-of-freedom force feedback mechanism, comprising a hybrid seven-degree-of-freedom mechanical arm, a base and a driving device, characterized in that: The hybrid seven-freedom robot arm includes a turntable, a closed-loop connecting rod mechanism, a sliding rod mechanism and an end actuator, the end actuator is connected to the sliding rod mechanism, the sliding rod mechanism is connected to the closed-loop connecting rod mechanism, the closed-loop connecting rod mechanism is connected to the turntable, the turntable is mounted on the base through a rotating pair, and the base is connected to the driving device.

2. A parallel-parallel seven-degree-of-freedom force feedback mechanism according to claim 1, characterized in that: The closed-loop connecting rod mechanism includes an upper long rod, a lower short rod, a lower long rod and an end rod, and the end rod is provided with two hinges, namely a middle hinge and an upper hinge. One end of the upper hinge is connected to one end of the upper long rod, and the other end of the upper long rod is hinged to the turntable through the rotating pair. The turntable is hinged to one end of the lower short rod through the rotating pair, and the other end of the lower short rod is connected to the lower long rod through the rotating pair. The other end of the lower long rod is hinged to the middle hinge, and the lower part of the end rod is connected to the sliding rod mechanism.

3. A parallel-parallel seven-degree-of-freedom force feedback mechanism according to claim 2, characterized in that: The sliding rod mechanism includes a sliding rod, a locking knob and a position sensor, wherein the position sensor is arranged at the upper part of the sliding rod, the sliding rod is slidingly connected to the end rod through a moving pair, a notch is arranged at the lower part of the end rod, the notch is connected to the locking knob, the locking knob locks the relative position of the sliding rod, and the end of the sliding rod is connected to the end actuator.

4. A parallel-parallel seven-degree-of-freedom force feedback mechanism according to claim 3, characterized in that: The end actuator includes an end handle, a first rotating shaft and a second rotating shaft. The second rotating shaft and the end handle, the second rotating shaft and the first rotating shaft are all connected through the rotating pair. The first rotating shaft is connected to the lower end of the sliding rod through the rotating pair. The three rotating pairs are perpendicular to each other.

5. A parallel-parallel seven-degree-of-freedom force feedback mechanism according to claim 4, characterized in that: The driving device includes a first driving motor, a second driving motor, a third driving motor, a first driven wheel and a second driven wheel, the second driven wheel is connected to the third driving motor, the third driving motor and the second driving motor are both fixed on the supporting structure of the turntable and arranged in parallel behind the closed-loop connecting rod mechanism.

6. A parallel-parallel seven-degree-of-freedom force feedback mechanism according to claim 5, characterized in that: The second driving motor drives the first driven wheel by wire transmission. The first driving motor is fixed on the base to drive the turntable to rotate.

7. A parallel-parallel seven-degree-of-freedom force feedback mechanism according to claim 6, characterized in that: The first driven wheel is fixedly connected to the lower short rod, the second driven wheel is fixedly connected to the upper long rod, the hinge points of the upper long rod and the turntable and the turntable and the lower short rod are arranged in parallel in the vertical direction, forming a planar five-bar mechanism with two degrees of freedom.

8. The hybrid seven-degree-of-freedom force feedback mechanism according to claim 7, characterized in that: The first driven wheel and the second driven wheel are both provided with a counterweight structure for balancing the deadweight of the closed-loop connecting rod mechanism.

9. A parallel-parallel seven-degree-of-freedom force feedback mechanism according to claim 8, characterized in that: Rotary encoders are installed at the rotating joints of the end actuator, and the first drive motor, the second drive motor and the third drive motor are all equipped with motor encoders, which are combined with the position sensor in the slide bar mechanism to realize real-time posture calculation of the end handle.

10. A parallel-parallel seven-degree-of-freedom force feedback mechanism according to claim 9, characterized in that: The base, the first driven wheel and the second driven wheel are provided with limiting grooves, and the turntable is respectively provided with three limiting columns which are slidably matched with the limiting grooves.

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