A three-degree-of-freedom two-translational and two-rotational parallel robot

Abstract

This invention relates to the field of parallel robot technology, specifically to a three-degree-of-freedom (DOF) parallel robot with two translational and two rotational degrees of freedom. Existing parallel robots mostly focus on rotational motion, with insufficient support for translational motion, making it difficult to fully simulate the natural movement patterns of the ankle. To address these problems, this invention provides a three-DOF parallel robot with two translational and two rotational degrees of freedom. Its topology includes a static platform, a moving platform, and hybrid branches I and II connecting the static and moving platforms. This topology realizes the two rotational degrees of freedom (inversion / eversion, dorsiflexion / plantarflexion) and two translational degrees of freedom required by the ankle joint, perfectly matching the natural movement patterns of the ankle. Compared to traditional parallel robots that only focus on rotational motion, this invention can more comprehensively simulate the complex movements of the ankle, providing a movement trajectory closer to the actual physiological state for rehabilitation training, thereby improving rehabilitation outcomes.

Description

Technical Field

[0001] This invention relates to the field of parallel machine mechanism technology, specifically to a three-degree-of-freedom parallel robot with two translational and two rotational degrees. Background Technology

[0002] In the field of medical rehabilitation, motor dysfunction caused by joint injuries or diseases is a common problem, especially for lower limb joints such as the ankle, where injuries can severely affect a patient's walking ability and quality of life. Traditional rehabilitation training methods often rely on the therapist's manual operation or simple equipment assistance, which has limitations such as difficulty in precisely controlling training intensity, a single training trajectory, and the inability to provide real-time feedback on training effects. These methods fail to meet the demands of modern rehabilitation medicine for personalized, precise, and efficient training.

[0003] With the rapid development of robotics technology, parallel robots, due to their advantages such as compact structure, high rigidity, strong load-bearing capacity, and high motion precision, are gradually being applied in the field of rehabilitation training. Parallel robots, through the coordinated movement of multiple branches, can achieve complex multi-degree-of-freedom motion control, providing a new solution for joint rehabilitation training. However, existing parallel robots still have the following shortcomings when applied to ankle joint rehabilitation:

[0004] The degree of freedom configuration is unreasonable: the ankle joint has two rotational degrees of freedom, inversion / eversion (rotation about the x-axis) and dorsiflexion / plantarflexion (rotation about the y-axis), as well as slight translational requirements in the yoz plane (such as compression / traction). However, existing parallel robots mostly focus on rotational movements and do not provide sufficient support for translational movements, making it difficult to fully simulate the natural movement patterns of the ankle.

[0005] Insufficient mobility: Some parallel robots use a single-branch structure, which limits the movement trajectory and makes it impossible to achieve multi-directional and multi-mode compound movements, making it difficult to meet the needs of complex rehabilitation training for the ankle joint.

[0006] Complex driving and control: To achieve multi-degree-of-freedom motion, existing parallel robots typically require multiple actuators to work together, which increases system complexity and cost, while reducing motion stability and reliability.

[0007] Lack of targeted design: Existing parallel robots are mostly designed for general joints, without fully considering the anatomical characteristics of the ankle joint and the special needs of rehabilitation training, such as range of motion, load capacity, and safety.

[0008] To address the aforementioned problems, this invention proposes a three-degree-of-freedom parallel robot with two translational and two rotational degrees of freedom. Through optimized topological design, it achieves two rotational degrees of freedom (inversion / eversion and dorsiflexion / plantarflexion) for the ankle joint, as well as two-dimensional translational motion in the yoz plane. The robot employs a hybrid branched structure, combining planar six-bar parallel mechanisms and planar four-bar parallel mechanisms. Through reasonable rotational joint configuration and drive joint selection, it achieves high flexibility and precise control of motion. Furthermore, when applied to a human joint rehabilitation trainer, this robot can simulate the natural movement patterns of the ankle, providing controllable rehabilitation trajectories and resistance, meeting the needs of personalized and precise rehabilitation training, and offering a new and effective means for the rehabilitation treatment of patients with ankle joint injuries or diseases. Summary of the Invention

[0009] The problem with existing technologies is that most parallel robots focus on rotational motion and lack sufficient support for translational motion, making it difficult to fully simulate the natural movement patterns of the ankle. To address these issues, this invention provides a three-degree-of-freedom parallel robot with two translational and two rotational degrees of freedom. Its topology includes a static platform, a moving platform, and hybrid branches I and II connecting the static and moving platforms.

[0010] Hybrid branch I is formed by a planar six-bar parallel mechanism formed by sequentially connecting revolute joints and a connecting revolute joint connected in series. The two end sliding joints of the planar six-bar parallel mechanism are located on the stationary platform, and a connecting revolute joint is connected in series between the two end revolute joints of the planar six-bar parallel mechanism. The connecting revolute joint is connected to one end of the moving platform.

[0011] Hybrid branch II is formed by connecting a planar four-bar parallel mechanism with a series of rotating joints and a sub-chain formed by connecting several rotating joints in series. The end rotating joint at one end of the sub-chain is connected to the other end of the moving platform. The two end rotating joints of the planar four-bar parallel mechanism are located on the stationary platform. A bridging rotating joint is connected in series between the other two end rotating joints. The end rotating joint at the other end of the sub-chain is perpendicularly connected to the bridging rotating joint to form a hinge structure.

[0012] Using all end prismatic joints and any one end revolute joint on the static platform 0 as driving joints, the moving platform 1 moves in two dimensions within the YOZ plane (translation along the y-axis or along the z-axis) or around the bridge revolute joint R. 33 The axis of rotation or the rotational joint R connected to the bridge rotates. 33 The axis of the end rotating pair on the sub-chain that forms a hinge structure by vertical connection rotates.

[0013] In one specific embodiment, the planar six-bar parallel mechanism is composed of a first prismatic joint, a first rotary joint, a second rotary joint, a fourth rotary joint, a third rotary joint, and a second prismatic joint connected in series. The first prismatic joint and the second prismatic joint are both located on a stationary platform, and a connecting rotary joint is connected in series between the second rotary joint and the fourth rotary joint.

[0014] In one specific embodiment, the axes of the first rotary joint, the second rotary joint, the third rotary joint, and the fourth rotary joint are parallel to each other; the axes of the first prismatic joint and the first rotary joint are perpendicular to each other; the axes of the second prismatic joint and the third rotary joint are perpendicular to each other; the axes of the first prismatic joint and the second prismatic joint are perpendicular to each other; the axes of the connecting rotary joint and the fourth rotary joint are perpendicular to each other; and the axes of the connecting rotary joint and the second prismatic joint are perpendicular to each other.

[0015] In one specific implementation, the planar four-bar parallel mechanism is composed of a fifth revolute joint, a sixth revolute joint, an eighth revolute joint, and a seventh revolute joint connected in series. The fifth and seventh revolute joints are located on a stationary platform, and a bridging revolute joint is connected in series between the sixth and eighth revolute joints.

[0016] In one specific implementation, the axes of the fifth, sixth, seventh, and eighth rotary joints are parallel to each other, the axis of the bridging rotary joint is parallel to the axis of the sixth rotary joint, and the axes of the bridging rotary joint are perpendicular to the axes of the first and second sliding joints.

[0017] In one specific implementation, the sub-chain is formed by connecting the ninth and tenth rotating joints in series. The ninth rotating joint is perpendicularly connected to the bridge rotating joint to form a hinge structure, and the tenth rotating joint is connected to the other end of the moving platform.

[0018] In one specific implementation, the axes of the ninth and tenth revolute joints are parallel to each other, and the axis of the tenth revolute joint is parallel to the axis connecting the revolute joints.

[0019] Beneficial effects:

[0020] (1) This invention optimizes the topology to achieve the two rotational degrees of freedom (inversion / eversion, dorsiflexion / plantarflexion) and two translational degrees of freedom (translation along the y-axis or z-axis in the yoz plane) required by the ankle joint, perfectly matching the natural movement pattern of the ankle. Compared with the design of traditional parallel robots that only focus on rotational movement, this invention can more comprehensively simulate the complex movement of the ankle, providing a movement trajectory that is closer to the real physiological state for rehabilitation training, thereby improving the rehabilitation effect;

[0021] (2) This invention adopts a synergistic design of hybrid branch I and hybrid branch II, combined with a planar six-bar parallel mechanism and a planar four-bar parallel mechanism, and realizes multi-directional and multi-mode composite control of motion trajectory through reasonable series and vertical connection of multiple rotating joints. This structure not only expands the motion range of the moving platform, but also enhances the flexibility and adaptability of the movement, and can meet the needs of the ankle joint for diverse movement modes at different rehabilitation stages;

[0022] (3) This invention uses all end sliding joints and any one end rotating joint on the static platform as driving joints. By rationally selecting driving joints, the number of required actuators is reduced, simplifying the drive and control system. This design not only reduces system complexity and cost, but also improves the stability and reliability of motion, reduces the risk of errors and failures that may be caused by the coordinated work of multiple actuators, and provides safer and more stable motion support for rehabilitation training;

[0023] (4) This invention is specifically designed to address the anatomical characteristics of the ankle joint and the specific needs of rehabilitation training, such as range of motion, load capacity, and safety. By precisely controlling the motion trajectory and resistance of the moving platform, this invention can provide patients with personalized rehabilitation training programs to meet the needs of different injury degrees and rehabilitation stages. At the same time, the structural design of this invention also considers patient comfort and safety, ensuring the safety and effectiveness of the rehabilitation training process;

[0024] (5) The three-degree-of-freedom parallel robot with two translational and two rotational functions of the present invention is not only suitable for rehabilitation training of the ankle joint, but can also be applied to rehabilitation training of other joints, such as the wrist and elbow, through structural adjustment and parameter optimization. Its innovative design concept and significant technical advantages provide new technical means and solutions for the field of rehabilitation medicine, and are expected to promote the development of rehabilitation medicine towards a more personalized, precise and efficient direction. Attached Figure Description

[0025] Figure 1 This invention provides a schematic diagram of a three-degree-of-freedom parallel robot topology consisting of two translational and two rotational components.

[0026] In the diagram: 0 is the static platform, 1 is the dynamic platform, and P is the static platform. 11 First moving pair, R 12 First revolute joint, R 13 The second revolute joint, R 14 Connecting the rotating joint, P 21 Second moving pair, R 22 The third revolute joint, R 23 The fourth revolute joint, R 31 The fifth revolute joint, R 32 The sixth revolute joint, R 33 Bridge-connected rotating joint, R 41 The seventh revolute joint, R 42 The eighth revolute joint, R 34 The ninth revolute joint, R 35 The tenth rotating joint. Detailed Implementation

[0027] The present invention will be described in detail below with reference to embodiments. However, it should be understood that the following embodiments are merely illustrative examples of implementation of the present invention and are not intended to limit the scope of the present invention.

[0028] As per the instruction manual Figure 1 The diagram shows a three-degree-of-freedom parallel robot with two translational and two rotational axes, provided by this invention. Its topology includes a static platform 0, a moving platform 1, and hybrid branches I and II connecting the static platform 0 and the moving platform 1.

[0029] Hybrid branch I is a planar six-bar parallel mechanism formed by sequentially connecting revolute joints, and is connected to revolute joint R. 14 The planar six-bar parallel mechanism is composed of two prismatic joints at its two ends, which are located on a stationary platform O. A connecting revolute joint R is connected in series between the two revolute joints at its two ends. 14 Connecting revolute joint R 14 Connected to one end of the moving platform 1;

[0030] Hybrid branch II is formed by connecting a planar four-bar parallel mechanism with a series of revolute joints and a sub-chain with a series of revolute joints. The end revolute joint at one end of the sub-chain is connected to the other end of the moving platform 1. The two end revolute joints of the planar four-bar parallel mechanism are located on the stationary platform 0, and the other two end revolute joints are connected in series by a bridging revolute joint R. 33 The end revolute joint at the other end of the sub-chain is connected to the bridge revolute joint R. 33 Vertical connections form a hinge structure;

[0031] Using all end prismatic joints and any one end revolute joint on the static platform 0 as driving joints, the moving platform 1 moves in two dimensions within the YOZ plane (translation along the y-axis or along the z-axis) or around the bridge revolute joint R. 33 The axis of rotation or the rotational joint R connected to the bridge rotates. 33 The end revolute joint R on the sub-chain that forms a hinge structure by vertical connection 34 The axis rotates.

[0032] In one specific implementation, the planar six-bar parallel mechanism is composed of a first sliding joint P. 11 First revolute joint R 12 Second revolute joint R 13 Fourth revolute joint R 23 Third revolute joint R 22 Second moving sub-P 21 The first locating joint P is connected in series. 11 Second moving pair P 21 All are located on the static platform 0, the second revolute joint R 13 With the fourth revolute joint R 23 A revolute joint R is connected in series between them. 14.

[0033] In one specific implementation, the first rotating joint R 12 Second revolute joint R 13 Third revolute joint R 22 Fourth revolute joint R 23 The axes are parallel to each other, and the first sliding joint P 11 With the first revolute joint R 12 The axes are perpendicular to each other, and the second sliding joint P 21 With the third revolute joint R 22 The axes are perpendicular to each other, and the first sliding joint P 11 With the second moving sub-P 21 The axes are perpendicular to each other, and the connecting revolute joint R 14 With the fourth revolute joint R 23 The axes are perpendicular to each other, and the connecting revolute joint R 14 With the second moving sub-P 21 The axes are perpendicular to each other.

[0034] In one specific implementation, the planar four-bar parallel mechanism consists of a fifth revolute joint R. 31 The sixth revolute joint R 32 Eighth rotating joint R 42 7th rotating joint R 41 The fifth revolute joint R is connected in series. 31 and the seventh revolute joint R 41 Located on the static platform 0, the sixth rotary joint R 32 Eighth rotating joint R 42 A bridge-connected revolute joint R is connected in series between them. 33 .

[0035] In one specific implementation, the fifth revolute joint R 31 The sixth revolute joint R 32 7th rotating joint R 41 Eighth rotating joint R 42 The axes are parallel to each other, and the bridge-connected revolute joint R 33 With the sixth revolute joint R 32 The axes are parallel to each other, and the bridge-connected revolute joint R 33 With the first moving sub-P 11 Second moving sub-P 21 The axes are perpendicular to each other.

[0036] In one specific implementation, the subchain is formed by the ninth revolute joint R. 34 With the tenth revolute joint R 35 The ninth revolute joint R is formed by connecting them in series. 34 The tenth revolute joint R is perpendicularly connected to the bridge revolute joint to form a hinge structure. 35 Connect to the other end of the moving platform 1.

[0037] In one specific implementation, the ninth rotating joint R 34 With the tenth revolute joint R 35 The axes are parallel to each other, and the tenth revolute joint R 35 The axis of the connecting revolute joint R 14 The axes are parallel to each other.

[0038] A human joint rehabilitation trainer employs the topology of a three-degree-of-freedom parallel robot with two translational and two rotational axes as its robot topology. A foot fixator is mounted on the moving platform 1 of the topology. With the patient's foot fixed to the moving platform 1, the human joint rehabilitation trainer can simulate ankle inversion / eversion rotation around the x-axis and dorsiflexion / plantarflexion rotation around the y-axis, combined with slight compression / traction for translation along the y-axis or z-axis in the yoz plane. This actively trained human joint rehabilitation trainer provides controllable rehabilitation trajectories and resistance.

[0039] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A three-degree-of-freedom parallel robot with two translational and two rotational degrees, characterized in that, The topology includes a static platform (0), a moving platform (1), and hybrid branches I and II connecting the static platform (0) and the moving platform (1). Hybrid branch I is a planar six-bar parallel mechanism formed by sequentially connecting revolute joints, and is connected to the revolute joint (R). 14 The planar six-bar parallel mechanism is composed of two sliding joints at its two ends located on a stationary platform (0), and a connecting rotary joint (R) is connected in series between the two rotating joints at its two ends. 14 ), connecting rotating joint (R 14 ) is connected to one end of the moving platform (1); Hybrid branch II is formed by connecting a planar four-bar parallel mechanism with a series of revolute joints and a sub-chain formed by connecting several revolute joints in series. The end revolute joint at one end of the sub-chain is connected to the other end of the moving platform (1). The two end revolute joints of the planar four-bar parallel mechanism are located on the stationary platform (0). The other two end revolute joints are connected in series by a bridging revolute joint (R). 33 The end revolute joint at the other end of the sub-chain and the bridging revolute joint (R) 33 Vertical connections form a hinge structure; Using all end prismatic joints and any one end revolute joint on the static platform (0) as driving joints, the moving platform (1) moves in two dimensions in the YOZ plane or around the bridge revolute joint (R). 33 The axis of rotation or the rotational pair connected to the bridge (R) rotates. 33 The axis of the end rotating pair on the sub-chain that forms a hinge structure is rotated.

2. The three-degree-of-freedom parallel robot with two translational and two rotational degrees of freedom according to claim 1, characterized in that, The planar six-bar parallel mechanism consists of the first prismatic joint (P) 11 ), first revolute joint (R) 12 ), second revolute joint (R) 13 ), fourth revolute joint (R) 23 ), third revolute joint (R) 22 ), second moving pair (P) 21 The first prismatic joint (P) is connected in series. 11 ) and second moving pair (P 21 All are located on the static platform (0), and the second rotary joint (R) is located on the static platform (0). 13 ) and the fourth revolute joint (R 23 A rotating joint (R) is connected in series between them. 14 ).

3. A three-degree-of-freedom parallel robot with two translational and two rotational degrees of freedom according to claim 2, characterized in that, First rotating joint (R) 12 ), second revolute joint (R) 13 ), third revolute joint (R) 22 ), fourth revolute joint (R) 23 The axes of the first sliding joint (P) are parallel to each other. 11 ) and the first revolute joint (R 12 The axes of the two parts are perpendicular to each other, and the second sliding joint (P) 21 ) and the third revolute joint (R 22 The axes of the first sliding joint (P) are perpendicular to each other. 11 ) and the second moving pair (P 21 The axes of the two parts are perpendicular to each other, and they are connected by a revolute joint (R). 14 ) and the fourth revolute joint (R 23 The axes of the two parts are perpendicular to each other, and they are connected by a revolute joint (R). 14 ) and the second moving pair (P 21 The axes of the two axes are perpendicular to each other.

4. A three-degree-of-freedom parallel robot with two translational and two rotational degrees of freedom according to claim 1, characterized in that, The planar four-bar parallel mechanism consists of a fifth revolute joint (R). 31 ), sixth revolute joint (R) 32 ), the eighth revolute joint (R) 42 ), the seventh revolute joint (R) 41 The fifth revolute joint (R) is formed by connecting them in series. 31 ) and the seventh revolute joint (R 41 Located on the static platform (0), the sixth rotary joint (R) 32 ), the eighth revolute joint (R) 42 A bridge-connected revolute joint (R) is connected in series between them. 33 ).

5. A three-degree-of-freedom parallel robot with two translational and two rotational degrees of freedom according to claim 4, characterized in that, Fifth revolute joint (R) 31 ), sixth revolute joint (R) 32 ), the seventh revolute joint (R) 41 ), the eighth revolute joint (R) 42 The axes of the two parts are parallel to each other, and the bridge-connected revolute joint (R) 33 ) and the sixth revolute joint (R 32 The axes of the two parts are parallel to each other, and the bridge-connected revolute joint (R) 33 ) and the first moving pair (P 11 ), second moving pair (P) 21 The axes of the two axes are perpendicular to each other.

6. A three-degree-of-freedom parallel robot with two translational and two rotational degrees of freedom according to claim 1, characterized in that, The subchain consists of the ninth revolute joint (R) 34 ) and the tenth revolute joint (R 35 The ninth revolute joint (R) is formed by connecting them in series. 34 The tenth revolute joint (R) is perpendicularly connected to the bridge's rotating joint to form a hinge structure. 35 ) is connected to the other end of the moving platform (1).

7. A three-degree-of-freedom parallel robot with two translational and two rotational degrees of freedom according to claim 6, characterized in that, Ninth Rotary Joint (R) 34 ) and the tenth revolute joint (R 35 The axes of the tenth revolute joint (R) are parallel to each other. 35 The axis of the joint and the connecting rotating pair (R) 14 The axes of the two axes are parallel to each other.

8. A human joint rehabilitation training device, characterized in that, The topology of the three-degree-of-freedom two-translation two-rotation parallel robot described in any one of claims 1-7 is used as the topology of the human joint rehabilitation trainer. A foot fixation device is installed on the moving platform (1) of the topology.

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