Four-degree-of-freedom robot platform based on four branched chains and flight simulator

Abstract

The invention relates to the technical field of parallel mechanisms, in particular to a four-degree-of-freedom robot platform and flight simulator based on four branched chains, which comprises a first branched chain, a second branched chain, a third branched chain, a fourth branched chain, a static platform and a movable platform, the first branch chain, the second branch chain, the third branch chain and the fourth branch chain are all simple branch chains composed of the least kinematic pairs, the number of the kinematic pairs is small, the motion inertia can be reduced, the motion precision can be improved, and the second branch chain, the third branch chain and the fourth branch chain are completely the same in structure. The three same branched chains can control the motion trail of the movable platform by adopting an algorithm with the same essence, the motion trail of the movable platform is easier to obtain, input-output motion decoupling is achieved, and the motion precision and the dynamic performance are improved; besides, all the driving pairs are moving pairs, the moving pairs serving as the driving pairs are arranged in the X-axis direction, the Y-axis direction and the Z-axis direction respectively, the branched chains are not prone to interference, and the movable platform can obtain larger working space.

Description

Technical Field

[0001] This invention relates to the field of parallel mechanism technology, and in particular to a four-degree-of-freedom robot platform and flight simulator based on a four-branch chain. Background Technology

[0002] There is a significant lack of development in academia and industry into diverse application scenarios for 1T3R parallel mechanisms that truly match their inherent degrees of freedom. A large number of potential fields that could benefit from this specific motion capability (such as precision manufacturing / assembly, high-end testing, special operation robots, creative interactive devices, and flight motion platform simulation) have not yet been systematically explored and verified in practice. This lag in application development, in turn, restricts targeted research on mechanism optimization and performance improvement for specific application needs. Currently, research on parallel mechanisms with one translation and three rotations (1T3R) faces significant bottlenecks in terms of configuration innovation. The design ideas of most mechanisms discussed in the literature are often limited to relatively simple derivations of the basic configuration, resulting in non-decoupling of motion and lack of symbolic position correct solutions. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a four-degree-of-freedom robot platform and flight simulator based on a four-branch chain in order to overcome the shortcomings of the prior art.

[0004] The technical solution adopted by the present invention to solve its technical problem is: a four-degree-of-freedom robot platform based on four branches, including a first branch, a second branch, a third branch, a fourth branch, a static platform and a dynamic platform; The first branch includes a movable joint and a ball joint that are interconnected; The second branch includes a sliding joint 2, a rotating joint 1 and a rotating joint 2 connected in series with their axes parallel to each other, and the rotating joint 2 is connected to a ball joint 2; The third branch includes a locating joint three, a rotating joint three, and a rotating joint four, whose axes are parallel to each other and connected in series. The rotating joint four is connected to the ball joint three. The fourth branch includes a sliding joint four, a rotating joint five, and a rotating joint six whose axes are parallel to each other and connected in series. The rotating joint six is ​​connected to the ball joint four. The first, second, third, and fourth movable joints are all mounted on a static platform. The axes of the second, third, and fourth movable joints are perpendicular to each other, and the axis of the third movable joint is parallel to the axis of the first movable joint. The ball joints one, two, three and four are all mounted on the moving platform.

[0005] Furthermore, the first, second, third, and fourth spherical sub-units are distributed at the four vertices of the square.

[0006] Furthermore, the axis of the fourth movable joint is parallel to the X-axis, the axes of the second movable joint are both parallel to the Y-axis, and the axes of the first and third movable joints are both parallel to the Z-axis. When the first, second, third, and fourth prismatic joints are driving joints, the moving platform can generate output motions of translation along the Z-axis, rotation around the X-axis, rotation around the Y-axis, and rotation around the Z-axis.

[0007] The present invention also provides a flight simulator, including the above-mentioned four-degree-of-freedom robot platform based on four branches.

[0008] The beneficial effects of this invention are as follows: The four-degree-of-freedom robot platform based on four branches has its moving platform displacement along the Z-axis determined only by prismatic joint one, which is beneficial for real-time control of vertical motion, trajectory planning and dynamic analysis. The values ​​of the moving platform rotation around the X-axis, rotation around the Y-axis and rotation around the Z-axis are all determined by prismatic joint one, prismatic joint two, prismatic joint three and prismatic joint four, which has input-output motion decoupling, makes it easy to obtain the symbolic positive position solution, simplifies the kinematic model and control algorithm, and improves motion accuracy and dynamic performance. More importantly, the first, second, third and fourth branches of this four-degree-of-freedom robot platform are all simple branches composed of the fewest kinematic pairs. The small number of kinematic pairs can reduce the moment of inertia and improve the motion accuracy. Moreover, the second, third and fourth branches have the same structure. The three identical branches can use essentially the same algorithm to control the motion trajectory of the moving platform, making it easier to obtain the motion trajectory of the moving platform and also facilitating manufacturing and assembly. In addition, all the drive pairs of this four-degree-of-freedom robot platform are prismatic pairs, and there are prismatic pairs as drive pairs in the X-axis, Y-axis and Z-axis directions. The branches are less likely to interfere with each other, and the moving platform can obtain a larger workspace. Attached Figure Description

[0009] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0010] Figure 1 It is a parallel mechanism of one translation and three rotations with decoupled motion.

[0011] In the diagram: 0, static platform; 1, dynamic platform; P 11 , Moving sub-one, P 21 1. Moving secondary, P 31 1. Mobile Sub-3, P 41 1. Move the fourth sub-unit; R 22 Rotating joint 1, R 23Rotating joint two, R 32 Rotating joint three, R 33 Rotating joint four, R 42 Rotating joint five, R 43 Sixth rotating joint; S 12 , ball vice one, S 24 , Ball secondary, S 34 , Ball Vice Three, S 44 , Ball Vice Four.

[0012] I. First branch, II. Second branch, III. Third branch, IV. Fourth branch. Detailed Implementation

[0013] The invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams, illustrating only the basic structure of the invention in a schematic manner. Therefore, they only show the components relevant to the invention. Orientations and references (e.g., up, down, left, right, etc.) are only used to aid in the description of the features in the drawings. Therefore, the following specific embodiments are not intended to be limiting, and the scope of the claimed subject matter is defined solely by the appended claims and their equivalents.

[0014] Example 1

[0015] like Figure 1 As shown, a four-degree-of-freedom robot platform based on four branches includes a first branch I, a second branch II, a third branch III, a fourth branch IV, a static platform 0, and a dynamic platform 1. The first branch I includes interconnected movable joints P 11 And the ball vice-S 12 ; forming a simple branch consisting of the fewest kinematic pairs; The second branch II includes two sliding joints P whose axes are parallel to each other and connected in series. 21 Rotating joint R 22 and rotating pair 2R 23 The rotating pair R 23 Connecting to ball-type secondary S 24 It forms a simple branch consisting of the fewest kinematic pairs, and the second branch II can generate output motion of three-dimensional translation and three-dimensional rotation. The third branch III includes three parallel and sequentially connected sliding joints (P). 31 Rotating joint three R 32 and rotating joint four R 33 The revolute joint four R 33 Connecting to the ball-type secondary three S 34 It forms a simple branch chain consisting of the fewest kinematic pairs, and the third branch chain III can generate output motion of three-dimensional translation and three-dimensional rotation. The fourth branch IV includes four sliding joints P whose axes are parallel to each other and connected in series. 41 Rotating joint five R 42 and rotating joint six R 43 The rotating joint six R 43 Connected to ball-type four-S 44 ; forming a simple branch consisting of the fewest kinematic pairs; The moving pair P 11 Mobile secondary P 21 Mobile secondary 3P 31 and mobile secondary four P 41 All are set on static platform 0, the moving sub-P 21 The axis, the sliding joint three P 31 The axis and the four-P sliding joint 41 The axes are perpendicular to each other, and the moving joint is three P 31 The axis and the sliding joint P 11 The axes are parallel; Mobile Sub-P 11 The axis and the sliding joint P 11 Their directions of movement are consistent; Mobile secondary P 21 The axis and the sliding joint 2P 21 Their directions of movement are consistent; Mobile secondary three-P 31 The axis and the sliding joint of the three P 31 Their directions of movement are consistent; Mobile secondary quadrilateral 41 The axis and the four-P sliding joint 41 Their directions of movement are consistent; The ball pair one S 12 , Ball Second S 24 , Ball Sub-3S 34 and ball secondary four S 44 All are set on the dynamic platform 1.

[0016] In some examples, the ball is a sub-S 12 , Ball Second S 24 , Ball Sub-3S 34 and ball secondary four S 44 They are distributed at the four vertices of the square.

[0017] In some examples, the moving sub-four P 41 The axis is parallel to the X-axis direction, and the sliding joint P2 21 The axes of all parts are parallel to the Y-axis direction, and the sliding joint is P. 11 The axis and the moving joint of the three P 31 The axes are all parallel to the Z-axis direction; Mobile Sub-P 11 Mobile secondary P 21Mobile secondary 3P 31 and mobile secondary four P 41 When acting as a drive pair, the moving platform 1 can generate output motions of translation along the Z-axis, rotation around the X-axis, rotation around the Y-axis, and rotation around the Z-axis; the value of the rotation of the moving platform 1 around the X-axis is α, the value of the rotation of the moving platform 1 around the Y-axis is β, and the value of the rotation of the moving platform 1 around the Z-axis is θ, with the X-axis, Y-axis, and Z-axis directions being perpendicular to each other.

[0018] The four-degree-of-freedom robot platform has 4 degrees of freedom. When the stationary platform 0 is taken as the moving pair P... 11 Mobile secondary P 21 Mobile secondary 3P 31 and mobile secondary four P 41 As a driving pair, the moving platform 1 realizes one-dimensional translational motion output along the Z-axis and three-dimensional rotation. At the same time, it has a sub-kinematic chain with a topology of SKC(1,0,-1) and a coupling degree of 1.

[0019] The displacement of the moving platform 1 along the Z-axis is caused solely by the sliding joint P. 11 It is decided that the moving platform 1 will rotate around the X-axis. α The value of the rotation of the moving platform 1 around the Y-axis β The value of the rotation of the moving platform 1 around the Z-axis θ The angle values ​​are all determined by the sliding joint P. 11 Mobile secondary P 21 Mobile secondary 3P 31 and mobile secondary four P 41 The four factors determine that it has input-output motion decoupling, makes it easy to obtain the sign-positive position, simplifies the kinematic model and control algorithm, and improves motion accuracy and dynamic performance.

[0020] Example 2: A flight simulator, including the above-mentioned four-degree-of-freedom robot platform based on four branches, with the flight simulator's simulator cabin installed on the moving platform 1.

[0021] The four-degree-of-freedom robot platform in this implementation, through its architecture of vertical independent drive and three-axis coordinated rotation, can accurately reproduce the sense of acceleration and angular velocity of an aircraft, creating a realistic tactile environment for the pilot. An aircraft goes through takeoff, climb, cruise, descent, and landing phases to complete a full flight; in special circumstances, takeoff may be aborted. Figure 1 Taking a four-degree-of-freedom robot platform as an example, the entire process of flight simulation is described in detail.

[0022] Takeoff phase: The takeoff phase of an aircraft generally includes processes such as taxiing, wheel liftoff, takeoff, and acceleration climb. First, the locating joint P, which is the driving joint,11 This keeps the height of the moving platform 1 constant, through the moving sub-p that acts as the driving sub-particle. 11 Mobile secondary P 21 Mobile secondary 3P 31 and mobile secondary four P 41 The collaborative propulsion platform 1 tilts forward 10°-15°, creating a continuous longitudinal pressure sensation on the pilot's back; Secondly, in the instantaneous state after takeoff, the driving glider P... 11 The height of the controlled platform 1 is rapidly increased along the Z-axis to accurately reproduce the vertical acceleration caused by the sudden change in lift. Then, the platform is kept at a constant tilt angle to simulate the continuous rise of the aircraft.

[0023] Climb Phase: During this phase, the aircraft continues to climb. As it approaches cruising altitude, the pitch angle is gradually reduced, eventually transitioning to level flight. During this phase, the levitation pin (P)... 11 The moving platform 1 is raised at a constant rate to simulate a stable rate of ascent, via the moving sub-P. 11 Mobile secondary P 21 Mobile secondary 3P 31 and mobile secondary four P 41 Slowly control the tilt angle of the moving platform 1 until it becomes level, to simulate the flight climb state.

[0024] ③ Cruise Phase: During this phase, the aircraft flies smoothly, maintaining a constant altitude. It maintains its heading by fine-tuning roll using the ailerons. At this time, the levitation ailerons... 11 To maintain Z-axis height stability while remaining fixed in the current position, the prismatic joint P is continuously controlled by different motion laws. 11 Mobile secondary P 21 Mobile secondary 3P 31 and mobile secondary four P 41 The platform 1 is rotated in three dimensions to simulate the roll, yaw, pitch and other states of cruise flight.

[0025] ④ Descent Phase: During this phase, the aircraft descends at a slight nose-down angle, with negative vertical acceleration continuously accumulating. When the altitude drops to a certain value, the flaps are deployed to increase lift and establish a stable approach trajectory. At this time, the prismatic joint P is controlled. 11 The moving platform 1 is gradually lowered in a stepwise manner to reproduce the continuous vertical negative acceleration. The descent rate of the Z-axis is dynamically matched with the rate of change of the pitch angle to restore the real descent curve, and the moving platform 1 is controlled to tilt downwards gradually.

[0026] ⑤ Landing Phase: In contrast to takeoff, aircraft landing is a process of continuous decrease in altitude and speed until it reaches zero. The landing process mainly includes descent, leveling, glide, touchdown, and landing roll. The aircraft experiences a strong impact upon touchdown, followed by a prolonged deceleration process. Due to the use of engine thrust reversers, speed brakes, and other measures to increase drag, a relatively large deceleration rate is maintained during this phase. During this phase, the moving part P is continuously controlled. 11 This causes the Z-axis height of the moving platform 1 to gradually decrease, and drives the tilt angle of platform 1 to gradually level out. At the instant of grounding, the control of the moving pair P is activated. 11 The platform 1 descends and accelerates, then the moving sub-P... 11 Instantaneous locking is used to simulate the impact of grounding and to prevent attitude disturbances, making the simulation of vertical impacts more crisp, efficient, and responsive. Finally, the control of the moving joint P is performed. 11 Mobile secondary P 21 Mobile secondary 3P 31 and mobile secondary four P 41 The platform 1 is tilted backward to simulate reverse braking.

[0027] The Z-axis motion requires only a single drive pair for control, which can more accurately and flexibly simulate the takeoff and landing phases, while avoiding the unnatural feeling caused by motion coupling in traditional six-degree-of-freedom platforms.

[0028] The above description, based on the preferred embodiments of the present invention, provides inspiration. 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 claims.

Claims

1. A four-degree-of-freedom robot platform based on four branches, characterized in that: It includes the first branch (Ⅰ), the second branch (Ⅱ), the third branch (Ⅲ), the fourth branch (Ⅳ), the static platform (0), and the dynamic platform (1); The first branch (I) includes interconnected mobile pairs (P) 11 ) and ball vice one (S 12 ); The second branch (II) comprises two parallel sliding joints (P) connected in series with each other. 21 ), Rotary joint 1 (R) 22 ) and rotating pair two (R 23 ), the rotating pair two (R 23 ) connected to the ball secondary (S) 24 ); The third branch (Ⅲ) comprises three parallel and sequentially connected sliding joints (P) 31 ), rotating joint three (R) 32 ) and rotating joint four (R 33 The revolute joint four (R) 33 ) Connected to the ball secondary three (S 34 ); The fourth branch (Ⅳ) comprises four parallel and sequentially connected sliding joints (P) 41 ), Rotary joint five (R) 42 ) and rotating joint six (R 43 The revolute joint six (R) 43 ) Connected to the ball secondary four (S 44 ); The moving pair one (P) 11 ), and the second mobile unit (P) 21 ), mobile secondary three (P) 31 ) and moving secondary four (P 41 All are set on the static platform (0), and the moving sub-sub (P) is located on the static platform (0). 21 The axis of the moving joint (P) 31 The axis of the ) and the four moving joints (P) 41 The axes of the three moving pairs (P) are perpendicular to each other. 31 The axis of ) and the sliding joint 1 (P) 11 The axes are parallel; The ball pair one (S) 12 ), Ball Second (S 24 ), ball secondary three (S 34 ) and ball secondary four (S 44 All are set on the moving platform (1).

2. The four-degree-of-freedom robot platform based on four branches according to claim 1, characterized in that: The ball pair one (S) 12 ), Ball Second (S 24 ), ball secondary three (S 34 ) and ball secondary four (S 44 The shapes are distributed at the four vertices of the square.

3. The four-degree-of-freedom manipulator based on a four-branch chain according to claim 1, characterized in that: The moving pair four (P) 41 The axis of the sliding joint (P) is parallel to the X-axis direction. 21 The axes of all the moving pairs (P) are parallel to the Y-axis direction. 11 The axis and the moving joint three (P) 31 The axes of all are parallel to the Z-axis direction; The moving pair one (P) 11 ), and the second mobile unit (P) 21 ), mobile secondary three (P) 31 ) and moving secondary four (P 41 When ) is the driving pair, the moving platform (1) can generate output motions of translation along the Z-axis, rotation around the X-axis, rotation around the Y-axis and rotation around the Z-axis.

4. A flight simulator, characterized in that: Including the four-degree-of-freedom robot platform based on four branches as described in any one of claims 1-3.

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