Foot type robot stability testing device based on under-actuated multi-loop mechanism

Abstract

The invention discloses a foot type robot stability testing device based on an underactuated multi-loop mechanism. The device comprises a base, a first underactuated connecting rod mechanism, a second underactuated connecting rod mechanism, a third underactuated connecting rod mechanism, a flywheel adjusting mechanism and a synchronous fixing and locking mechanism. The combined movement of the under-actuated connecting rod mechanism and the flywheel adjusting mechanism can generate random disturbance, meanwhile, the size of the random disturbance can be adjusted, the synchronous locking mechanism can convert the mechanism into a fixed rack mechanism capable of generating fixed disturbance, and meanwhile the direction of the disturbance can be adjusted. And the same mechanism can meet the requirements of various test environments.

Description

Technical Field

[0001] The present invention belongs to the technical field of legged robots, and particularly relates to a stability testing device for legged robots based on an underactuated multi-loop mechanism. Background Art

[0002] With the wide application of legged robot technology in complex scenarios such as industrial inspection, disaster rescue, and warehousing logistics, the dynamic stability of legged robots has become the core index determining the safety and reliability of operations.

[0003] Traditional stability testing methods for legged robots usually adopt full-drive or fixed-drive methods, and test the robot through preset disturbance signals. To a certain extent, these methods can evaluate the dynamic characteristics of the system, but there are some limitations. For example, the disturbance pattern is single: traditional methods mainly focus on single or periodic disturbances, and it is difficult to reflect the interference of random and diverse environmental factors in actual applications; the applicable scenarios are limited: due to the fixed disturbance parameters, the test results are often limited to the stability evaluation under a certain specific working state, and it is difficult to cover a wider range of application scenarios. Summary of the Invention

[0004] The purpose of the present invention is to provide a stability testing device for legged robots based on an underactuated multi-loop mechanism in view of the deficiencies of the prior art.

[0005] The purpose of the present invention is achieved through the following technical solutions: A stability testing device for legged robots based on an underactuated multi-loop mechanism, the device includes a base, a first underactuated link mechanism, a second underactuated link mechanism, a third underactuated link mechanism, a flywheel adjustment mechanism, and a synchronous locking mechanism;

[0006] One ends of the first underactuated link mechanism, the second underactuated link mechanism, and the third underactuated link mechanism are respectively fixedly connected to the base by screws, and the other ends are respectively connected to the bottom of the flywheel adjustment mechanism and are evenly distributed around the base; the flywheel adjustment mechanism is located at the central position of the stability testing device for legged robots based on an underactuated multi-loop mechanism; one end of the synchronous locking mechanism is connected to the base, and the other end is respectively connected to the first underactuated link mechanism, the second underactuated link mechanism, and the third underactuated link mechanism;

[0007] The flywheel adjustment mechanism is used to generate an adjustable disturbance torque and transmit it to the first underactuated link mechanism, the second underactuated link mechanism, and the third underactuated link mechanism;

[0008] The first underactuated link mechanism, the second underactuated link mechanism, and the third underactuated link mechanism are respectively used to randomize the disturbance torque and conduct it to the base;

[0009] The synchronous locking mechanism is used to fix the first underactuated linkage mechanism, the second underactuated linkage mechanism, and the third underactuated linkage mechanism at any position.

[0010] Further, the first underactuated linkage mechanism is composed of a first fixed base, a first rotating rod, a first base connecting shaft, a first cylindrical rod, a first arc rod, a first rotating rod connecting shaft, and a first moving platform connecting shaft; the first fixed base is an L-shaped rod, the lower part of the first fixed base is fixedly connected to the base by screws, and the upper part of the first fixed base is connected to the upper part of the first rotating rod through the first base connecting shaft to form a first rotating pair; the lower part of the first rotating rod is connected to the lower end of the first cylindrical rod through the first rotating rod connecting shaft to form a second rotating pair; the upper end of the first cylindrical rod is fixedly connected to the lower end of the first arc rod by screws; the upper end of the first arc rod is connected to the flywheel adjusting mechanism through the first moving platform connecting shaft to form a third rotating pair;

[0011] The second underactuated linkage mechanism is composed of a second fixed base, a second rotating rod, a second base connecting shaft, a second cylindrical rod, a second arc rod, a second rotating rod connecting shaft, and a second moving platform connecting shaft; the second fixed base is an L-shaped rod, the lower part of the second fixed base is fixedly connected to the base by screws, and the upper part of the second fixed base is connected to the upper part of the second rotating rod through the second base connecting shaft to form a fourth rotating pair; the lower part of the second rotating rod is connected to the lower end of the second cylindrical rod through the second rotating rod connecting shaft to form a fifth rotating pair; the upper end of the second cylindrical rod is fixedly connected to the lower end of the second arc rod by screws; the upper end of the second arc rod is connected to the flywheel adjusting mechanism through the second moving platform connecting shaft to form a sixth rotating pair;

[0012] The third underactuated linkage mechanism is composed of a third fixed base, a third rotating rod, a third base connecting shaft, a third cylindrical rod, a third arc rod, a third rotating rod connecting shaft, and a third moving platform connecting shaft; the third fixed base is an L-shaped rod, the lower part of the third fixed base is fixedly connected to the base by screws, and the upper part of the third fixed base is connected to the upper part of the third rotating rod through the third base connecting shaft to form a seventh rotating pair; the lower part of the third rotating rod is connected to the lower end of the third cylindrical rod through the third rotating rod connecting shaft to form an eighth rotating pair; the upper end of the third cylindrical rod is fixedly connected to the lower end of the third arc rod by screws; the upper end of the third arc rod is connected to the flywheel adjusting mechanism through the third moving platform connecting shaft to form a ninth rotating pair.

[0013] Further, the flywheel adjusting mechanism is composed of a moving platform, a height adjusting mechanism, a servo motor, a flywheel, an eccentric block, and an adjusting screw;

[0014] The moving platform consists of a moving platform body, adjustment holes, a first mounting boss, a second mounting boss, and a third mounting boss; the moving platform body is a hollow cylindrical structure; the first mounting boss, the second mounting boss, and the third mounting boss are respectively fixedly connected to the moving platform body by screws and are evenly distributed at the lower part of the moving platform body; the first mounting boss is connected to the first arc-shaped rod by a first moving platform connecting shaft to form a third rotating pair; the second mounting boss is connected to the second arc-shaped rod by a second moving platform connecting shaft to form a sixth rotating pair; the third mounting boss is connected to the third arc-shaped rod by a third moving platform connecting shaft to form a ninth rotating pair;

[0015] The upper part of the height adjustment mechanism is fixedly connected to the servo motor by screws, and the height adjustment mechanism cooperates with the moving platform through the adjustment holes to form a first translation pair; the upper part of the servo motor cooperates with the flywheel to form a tenth rotating pair; a first chute is provided on the upper part of the flywheel to cooperate with the eccentric block to form a second translation pair; the adjustment screw cooperates with the eccentric block to fix the eccentric block in the first chute.

[0016] Further, the height adjustment mechanism consists of a height adjustment platform, a first spring, a second spring, a third spring, a fourth spring, a first fixed buckle, a second fixed buckle, a third fixed buckle, and a fourth fixed buckle; the height adjustment platform is a cylindrical structure, and the first notch, the second notch, the third notch, and the fourth notch are evenly provided around it; the lower part of the first fixed buckle extends and retracts along the direction of the first notch through the first spring to form a third translation pair; the lower part of the second fixed buckle extends and retracts along the direction of the second notch through the second spring to form a fourth translation pair; the lower part of the third fixed buckle extends and retracts along the direction of the third notch through the third spring to form a fifth translation pair; the lower part of the fourth fixed buckle extends and retracts along the direction of the fourth notch through the fourth spring to form a sixth translation pair.

[0017] Further, the synchronous locking mechanism includes a driving mechanism, a first braking mechanism, a second braking mechanism, a third braking mechanism, a first fixed guide rail, a second fixed guide rail, and a third fixed guide rail; the driving mechanism is fixed at the center of the base; the upper part of the first braking mechanism is connected to the first underactuated linkage mechanism, the upper part of the second braking mechanism is connected to the second underactuated linkage mechanism, and the upper part of the third braking mechanism is connected to the third underactuated linkage mechanism; the lower parts of the first braking mechanism, the second braking mechanism, and the third braking mechanism are respectively connected to one end of the driving mechanism, and the other end of the driving mechanism is fixed at the center of the base; the first fixed guide rail is respectively connected to the first braking mechanism and the first underactuated linkage mechanism; the second fixed guide rail is respectively connected to the second braking mechanism and the second underactuated linkage mechanism; the third fixed guide rail is respectively connected to the third braking mechanism and the third underactuated linkage mechanism.

[0018] Further, the driving mechanism includes a stepper motor, a triangular connecting rod, a first secondary connecting rod, a second secondary connecting rod, a third secondary connecting rod, a first short pin shaft, a second short pin shaft, a third short pin shaft, a fourth short pin shaft, a fifth short pin shaft, and a sixth short pin shaft; the first braking mechanism includes a first braking slider, a second sliding groove, a first braking push rod, and a first braking brake pad; the second braking mechanism includes a second braking slider, a third sliding groove, a second braking push rod, and a second braking brake pad; the third braking mechanism includes a third braking slider, a fourth sliding groove, a third braking push rod, and a third braking brake pad; the first fixed guide rail is composed of a first braking slider guide rail and a first braking push rod guide rail; the second fixed guide rail is composed of a second braking slider guide rail and a second braking push rod guide rail; the third fixed guide rail is composed of a third braking slider guide rail and a third braking push rod guide rail;

[0019] The lower part of the stepper motor is fixedly connected to the base by screws, and the upper part is connected to the center of the triangular connecting rod to form an eleventh rotating pair;

[0020] The end of the first connecting rod in the triangular connecting rod is connected to one end of the first secondary connecting rod by a first short pin shaft to form a twelfth rotating pair; the other end of the first secondary connecting rod is connected to the first braking slider by a second short pin shaft to form a thirteenth rotating pair; the first braking slider guide rail is fixedly connected to the first fixed base by screws and cooperates with the first braking slider to form a seventh moving pair; the first braking slider is a trapezoidal rod, and a second sliding groove is provided on the upper part, which cooperates with the lower part of the first braking push rod to form an eighth moving pair; the first braking push rod guide rail is fixedly connected to the first fixed base by screws and cooperates with the first braking push rod to form a ninth moving pair; the lower part of the first braking brake pad is fixedly connected to the upper part of the first braking push rod by screws, and the upper part of the first braking brake pad cooperates with the first rotating rod to lock the first rotating rod at any position; the lower part of the first braking push rod is of a long trapezoidal structure, and the upper part is of a cylindrical structure;

[0021] The end of the second link in the triangular link is connected to one end of the second secondary link by a third short pin shaft, forming a fourteenth revolute pair; the other end of the second secondary link is connected to the second brake slider by a fourth short pin shaft, forming a fifteenth revolute pair; the second brake slider guide rail is fixedly connected to the second fixed base by screws and cooperates with the second brake slider to form a tenth prismatic pair; the second brake slider is a trapezoidal rod, and a third chute is provided on the upper part, and the third chute cooperates with the lower part of the second brake push rod to form an eleventh prismatic pair; the second brake push rod guide rail is fixedly connected to the second fixed base by screws and cooperates with the second brake push rod to form a twelfth prismatic pair; the lower part of the second brake brake pad is fixedly connected to the upper part of the second brake push rod by screws, and the upper part of the second brake brake pad cooperates with the second rotating rod and can lock the second rotating rod at any position; the lower part of the second brake push rod is of a long trapezoidal structure, and the upper part is of a cylindrical structure;

[0022] The end of the third link in the triangular link is connected to one end of the third secondary link by a fifth short pin shaft, forming a sixteenth revolute pair; the other end of the third secondary link is connected to the third brake slider by a sixth short pin shaft, forming a seventeenth revolute pair; the third brake slider guide rail is fixedly connected to the third fixed base by screws and cooperates with the third brake slider to form a thirteenth prismatic pair; the third brake slider is a trapezoidal rod, and a fourth chute is provided on the upper part, and the fourth chute cooperates with the lower part of the third brake push rod to form a fourteenth prismatic pair; the third brake push rod guide rail is fixedly connected to the third fixed base by screws and cooperates with the third brake push rod to form a fifteenth prismatic pair; the lower part of the third brake brake pad is fixedly connected to the upper part of the third brake push rod by screws, and the upper part of the third brake brake pad cooperates with the third rotating rod and can lock the third rotating rod at any position; the lower part of the third brake push rod is of a long trapezoidal structure, and the upper part is of a cylindrical structure.

[0023] The beneficial effects of the present invention are: The present invention has the advantages of novel, compact structure, diverse functions, wide application range, simple control, etc. It is composed of a base, an underactuated link mechanism, a flywheel adjustment mechanism and a synchronous locking mechanism. The combined movement of the underactuated link mechanism and the flywheel adjustment mechanism can generate random disturbances, and at the same time, the magnitude of the random disturbances can be adjusted, while the synchronous locking mechanism can convert this mechanism into a fixed frame mechanism that can generate fixed disturbances, and at the same time, the orientation of the disturbances can be adjusted, so that the same mechanism can meet the requirements of multiple test environments. Description of the Drawings

[0024] Figure 1 It is a schematic diagram of the overall structure of a foot-type robot stability test device based on an underactuated multi-loop mechanism;

[0025] Figure 2Another overall structural schematic diagram of a stability testing device for a legged robot based on an underactuated multi-loop mechanism;

[0026] Figure 3 Exploded view of the first underactuated link mechanism;

[0027] Figure 4 Exploded view of the flywheel adjustment mechanism;

[0028] Figure 5 Exploded view of the moving platform;

[0029] Figure 6 Structural diagram of the synchronous locking mechanism;

[0030] Figure 7 Exploded view of the synchronous locking mechanism;

[0031] Figure 8 Schematic diagram of a stability testing device for a legged robot based on an underactuated multi-loop mechanism for biped robot stability testing;

[0032] Figure 9 Schematic diagram of a stability testing device for a legged robot based on an underactuated multi-loop mechanism for quadruped robot stability testing;

[0033] Figure 10 Schematic diagram of a stability testing device for a legged robot based on an underactuated multi-loop mechanism for hexapod robot stability testing;

[0034] In the figure, 1 - base; 2 - first underactuated link mechanism; 3 - second underactuated link mechanism; 4 - third underactuated link mechanism; 5 - flywheel adjustment mechanism; 6 - synchronous locking mechanism;

[0035] 21 - first fixed base; 22 - first rotating rod; 23 - first base connecting shaft; 24 - first cylindrical rod; 25 - first arc rod; 26 - first rotating rod connecting shaft; 27 - first moving platform connecting shaft;

[0036] 31 - second fixed base; 32 - second rotating rod; 33 - second base connecting shaft; 34 - second cylindrical rod; 35 - second arc rod; 36 - second rotating rod connecting shaft; 37 - second moving platform connecting shaft;

[0037] 41 - third fixed base; 42 - third rotating rod; 43 - third base connecting shaft; 44 - third cylindrical rod; 45 - third arc rod; 46 - third rotating rod connecting shaft; 47 - third moving platform connecting shaft;

[0038] 51 - Moving platform; 52 - Height adjustment mechanism; 53 - Servo motor; 54 - Flywheel; 55 - First chute; 56 - Eccentric block; 57 - Adjusting screw; 5101 - Moving platform body; 5102 - Adjusting hole; 5103 - First mounting boss; 5104 - Second mounting boss; 5105 - Third mounting boss; 5201 Height adjustment table; 52021 - First spring; 52022 - Second spring; 52023 - Third spring; 52024 - Fourth spring; 52031 - First fixed buckle; 52032 - Second fixed buckle; 52033 - Third fixed buckle; 52034 - Fourth fixed buckle;

[0039] 61 - Driving mechanism; 62 - First braking mechanism; 63 - Second braking mechanism; 64 - Third braking mechanism; 65 - First fixed guide rail; 66 - Second fixed guide rail; 67 - Third fixed guide rail; 6201 - First braking slider; 6202 - Second chute; 6203 - First braking push rod; 6204 - First braking brake pad; 6301 - Second braking slider; 6302 - Third chute; 6303 - Second braking push rod; 6304 - Second braking brake pad; 6401 - Third braking slider; 6402 - Fourth chute; 6403 - Third braking push rod; 6404 - Third braking brake pad; 6501 - First braking slider guide rail; 6502 - First braking push rod guide rail; 6601 - Second braking slider guide rail; 6602 - Second braking push rod guide rail; 6701 - Third braking slider guide rail; 6702 - Third braking push rod guide rail. Detailed implementation manners

[0040] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0041] As Figure 1 and Figure 2 shown, the present invention provides a stability test device for a legged robot based on an under - actuated multi - loop mechanism. The device includes a base 1, a first under - actuated link mechanism 2, a second under - actuated link mechanism 3, a third under - actuated link mechanism 4, a flywheel adjustment mechanism 5 and a synchronous locking mechanism 6.

[0042] The first underactuated linkage mechanism 2, the second underactuated linkage mechanism 3, and the third underactuated linkage mechanism 4 are respectively chain structures with the same structure and are evenly distributed around the base 1. One ends of the first underactuated linkage mechanism 2, the second underactuated linkage mechanism 3, and the third underactuated linkage mechanism 4 are respectively fixedly connected to the base 1 by screws, and the other ends are respectively connected to the bottom of the flywheel adjustment mechanism 5.

[0043] The flywheel adjustment mechanism 5 is located at the center of the stability test device of the legged robot based on the underactuated multi-loop mechanism and is connected to the first underactuated linkage mechanism 2, the second underactuated linkage mechanism 3, and the third underactuated linkage mechanism 4.

[0044] The flywheel adjustment mechanism 5 is used to generate an adjustable disturbing torque and transmit it to the first underactuated linkage mechanism 2, the second underactuated linkage mechanism 3, and the third underactuated linkage mechanism 4.

[0045] The first underactuated linkage mechanism 2, the second underactuated linkage mechanism 3, and the third underactuated linkage mechanism 4 are respectively used to randomize the disturbing torque and conduct it to the base 1;

[0046] One end of the synchronous locking mechanism 6 is connected to the base 1, and the other end is respectively connected to the first underactuated linkage mechanism 2, the second underactuated linkage mechanism 3, and the third underactuated linkage mechanism 4. It is used to fix the first underactuated linkage mechanism 2, the second underactuated linkage mechanism 3, and the third underactuated linkage mechanism 4 at any position and respectively convert the first underactuated linkage mechanism 2, the second underactuated linkage mechanism 3, and the third underactuated linkage mechanism 4 into fixed frame mechanisms.

[0047] The base 1 respectively has a supporting and fixing effect on the first underactuated linkage mechanism 2, the second underactuated linkage mechanism 3, the third underactuated linkage mechanism 4, and the synchronous locking mechanism 6.

[0048] Embodiment 2

[0049] As Figure 3As shown, the first underactuated linkage mechanism 2 is composed of a first fixed base 21, a first rotating rod 22, a first base connecting shaft 23, a first cylindrical rod 24, a first arc rod 25, a first rotating rod connecting shaft 26, and a first moving platform connecting shaft 27. The first fixed base 21 is an L-shaped rod. The lower part of the first fixed base 21 is fixedly connected to the base 1 by screws. The upper part of the first fixed base 21 is connected to the upper part of the first rotating rod 22 through the first base connecting shaft 23 to form a first rotating pair. The lower part of the first rotating rod 22 is connected to the lower end of the first cylindrical rod 24 through the first rotating rod connecting shaft 26 to form a second rotating pair. The upper end of the first cylindrical rod 24 is fixedly connected to the lower end of the first arc rod 25 by screws. The upper end of the first arc rod 25 is connected to the flywheel adjusting mechanism 5 through the first moving platform connecting shaft 27 to form a third rotating pair.

[0050] The second underactuated linkage mechanism 3 is composed of a second fixed base 31, a second rotating rod 32, a second base connecting shaft 33, a second cylindrical rod 34, a second arc rod 35, a second rotating rod connecting shaft 36, and a second moving platform connecting shaft 37. The second fixed base 31 is an L-shaped rod. The lower part of the second fixed base 31 is fixedly connected to the base 1 by screws. The upper part of the second fixed base 31 is connected to the upper part of the second rotating rod 32 through the second base connecting shaft 33 to form a fourth rotating pair. The lower part of the second rotating rod 32 is connected to the lower end of the second cylindrical rod 34 through the second rotating rod connecting shaft 36 to form a fifth rotating pair. The upper end of the second cylindrical rod 34 is fixedly connected to the lower end of the second arc rod 35 by screws. The upper end of the second arc rod 35 is connected to the flywheel adjusting mechanism 5 through the second moving platform connecting shaft 37 to form a sixth rotating pair.

[0051] The third underactuated linkage mechanism 4 is composed of a third fixed base 41, a third rotating rod 42, a third base connecting shaft 43, a third cylindrical rod 44, a third arc rod 45, a third rotating rod connecting shaft 46, and a third moving platform connecting shaft 47. The third fixed base 41 is an L-shaped rod. The lower part of the third fixed base 41 is fixedly connected to the base 1 by screws. The upper part of the third fixed base 41 is connected to the upper part of the third rotating rod 42 through the third base connecting shaft 43 to form a seventh rotating pair. The lower part of the third rotating rod 42 is connected to the lower end of the third cylindrical rod 44 through the third rotating rod connecting shaft 46 to form an eighth rotating pair. The upper end of the third cylindrical rod 44 is fixedly connected to the lower end of the third arc rod 45 by screws. The upper end of the third arc rod 45 is connected to the flywheel adjusting mechanism 5 through the third moving platform connecting shaft 47 to form a ninth rotating pair.

[0052] As Figure 4 and Figure 5As shown, the flywheel adjustment mechanism 5 is composed of a moving platform 51, a height adjustment mechanism 52, a servo motor 53, a flywheel 54, an eccentric block 56, and an adjustment screw 57.

[0053] The moving platform 51 is composed of a moving platform body 5101, adjustment holes 5102, a first mounting boss 5103, a second mounting boss 5104, and a third mounting boss 5105. A plurality of adjustment holes 5102 are provided around the moving platform body 5101. The first mounting boss 5103, the second mounting boss 5104, and the third mounting boss 5105 are respectively fixedly connected to the moving platform body 5101 by screws and are evenly distributed at the lower part of the moving platform body 5101. The first mounting boss 5103 is connected to the first arc-shaped rod 25 through a first moving platform connecting shaft 27 to form a third rotating pair; the second mounting boss 5104 is connected to the second arc-shaped rod 35 through a second moving platform connecting shaft 37 to form a sixth rotating pair; the third mounting boss 5105 is connected to the third arc-shaped rod 45 through a third moving platform connecting shaft 47 to form a ninth rotating pair.

[0054] The upper part of the height adjustment mechanism 52 is fixedly connected to the servo motor 53 by screws. The height adjustment mechanism 52 cooperates with the moving platform 51 through the adjustment holes 5102 to form a first moving pair, achieving the function of telescopic adjustment to fix the heights of the servo motor 53 and the flywheel 54, so that the moment of inertia of the flywheel 54 can be adjusted. The upper part of the servo motor 53 cooperates with the flywheel 54 to form a tenth rotating pair; a first sliding groove 55 is provided on the upper part of the flywheel 54 to cooperate with the eccentric block 56 to form a second moving pair. The adjustment screw 57 cooperates with the eccentric block 56 to fix the eccentric block 56 in the first sliding groove 55. By adjusting the position distribution of the eccentric block 56 in the first sliding groove 55, the moment of inertia of the flywheel 54 can be further adjusted. By adjusting the output torque of the servo motor 53, the angular acceleration of the flywheel 54 can be adjusted. Therefore, the magnitude of the disturbing torque generated by the flywheel 54 can be adjusted. Finally, the disturbing torque is converted into random disturbance through the first underactuated link mechanism 2, the second underactuated link mechanism 3, and the third underactuated link mechanism 4 and transmitted to the base 1.

[0055] The height adjustment mechanism 52 consists of a height adjustment table 5201, a first spring 52021, a second spring 52022, a third spring 52023, a fourth spring 52024, a first fixed buckle 52031, a second fixed buckle 52032, a third fixed buckle 52033, and a fourth fixed buckle 52034. The height adjustment table 5201 is of a cylindrical structure, and is evenly provided with a first notch, a second notch, a third notch, and a fourth notch around its circumference. The lower part of the first fixed buckle 52031 expands and contracts along the direction of the first notch through the first spring 52021 to form a third moving pair; the lower part of the second fixed buckle 52032 expands and contracts along the direction of the second notch through the second spring 52022 to form a fourth moving pair; the lower part of the third fixed buckle 52033 expands and contracts along the direction of the third notch through the third spring 52023 to form a fifth moving pair; the lower part of the fourth fixed buckle 52034 expands and contracts along the direction of the fourth notch through the fourth spring 52024 to form a sixth moving pair.

[0056] As Figures 6 to 7 shown, the synchronous locking mechanism 6 includes a driving mechanism 61, a first braking mechanism 62, a second braking mechanism 63, a third braking mechanism 64, a first fixed guide rail 65, a second fixed guide rail 66, and a third fixed guide rail 67. The driving mechanism 61 is fixed at the center of the base 1. The upper part of the first braking mechanism 62 is connected to the first underactuated link mechanism 2, the upper part of the second braking mechanism 63 is connected to the second underactuated link mechanism 3, and the upper part of the third braking mechanism 64 is connected to the third underactuated link mechanism 4. The lower parts of the first braking mechanism 62, the second braking mechanism 63, and the third braking mechanism 64 are respectively connected to one end of the driving mechanism 61, and the other end of the driving mechanism 61 is fixed at the center of the base 1. The first fixed guide rail 65 is respectively connected to the first braking mechanism 62 and the first underactuated link mechanism 2. The second fixed guide rail 66 is respectively connected to the second braking mechanism 63 and the second underactuated link mechanism 3. The third fixed guide rail 67 is respectively connected to the third braking mechanism 64 and the third underactuated link mechanism 4.

[0057] The driving mechanism 61 includes a stepper motor 6101, a triangular connecting rod 6102, a first secondary connecting rod 61031, a second secondary connecting rod 61032, a third secondary connecting rod 61033, a first short pin shaft 61041, a second short pin shaft 61042, a third short pin shaft 61043, a fourth short pin shaft 61044, a fifth short pin shaft 61045 and a sixth short pin shaft 61046. The first braking mechanism 62 includes a first braking slider 6201, a second sliding groove 6202, a first braking push rod 6203 and a first braking brake pad 6204. The second braking mechanism 63 includes a second braking slider 6301, a third sliding groove 6302, a second braking push rod 6303 and a second braking brake pad 6304. The third braking mechanism 64 includes a third braking slider 6401, a fourth sliding groove 6402, a third braking push rod 6403 and a third braking brake pad 6404. The first fixed guide rail 65 is composed of a first braking slider guide rail 6501 and a first braking push rod guide rail 6502. The second fixed guide rail 66 is composed of a second braking slider guide rail 6601 and a second braking push rod guide rail 6602. The third fixed guide rail 67 is composed of a third braking slider guide rail 6701 and a third braking push rod guide rail 6702.

[0058] The lower part of the stepper motor 6101 is fixedly connected to the base 1 by screws, and the upper part is connected to the center of the triangular connecting rod 6102 to form an eleventh rotating pair;

[0059] The end of the first link in the triangular link 6102 is connected to one end of the first two-stage link 61031 by a first short pin shaft 61041 to form the twelfth rotating pair; the other end of the first two-stage link 61031 is connected to the first brake slider 6201 by a second short pin shaft 61042 to form the thirteenth rotating pair; the first brake slider guide rail 6501 is fixedly connected to the first fixed base 21 by screws and cooperates with the first brake slider 6201 to form the seventh moving pair, enabling the first brake slider 6201 to move horizontally along the bottom end of the first fixed base 21; the first brake slider 6201 is a trapezoidal rod, and a second chute 6202 is provided on the upper part, which cooperates with the lower part of the first brake push rod 6203 to form the eighth moving pair, converting the horizontal movement of the first brake slider 6201 into the vertical movement of the first brake push rod 6203; the first brake push rod guide rail 6502 is fixedly connected to the first fixed base 21 by screws and cooperates with the first brake push rod 6203 to form the ninth moving pair, restricting the movement of the first brake push rod 6203 in the vertical direction of the first fixed base 21; the lower part of the first brake brake pad 6204 is fixedly connected to the upper part of the first brake push rod 6203 by screws, and the upper part of the first brake brake pad 6204 cooperates with the first rotating rod 22, and the first rotating rod 22 can be locked in any position; the lower part of the first brake push rod 6203 is of a long trapezoidal structure, and the upper part is of a cylindrical structure.

[0060] The end of the second link in the triangular link 6102 is connected to one end of the second secondary link 61032 by a third short pin shaft 61043 to form a fourteenth revolute pair; the other end of the second secondary link 61032 is connected to the second brake slider 6301 by a fourth short pin shaft 61044 to form a fifteenth revolute pair; the second brake slider guide rail 6601 is fixedly connected to the second fixed base 31 by screws and cooperates with the second brake slider 6301 to form a tenth prismatic pair, enabling the second brake slider 6301 to move horizontally along the bottom end of the second fixed base 31; the second brake slider 6301 is a trapezoidal rod, and a third chute 6302 is provided on the upper part, which cooperates with the lower part of the second brake push rod 6303 to form an eleventh prismatic pair, converting the horizontal movement of the second brake slider 6301 into the vertical movement of the second brake push rod 6303; the second brake push rod guide rail 6602 is fixedly connected to the second fixed base 31 by screws and cooperates with the second brake push rod 6303 to form a twelfth prismatic pair, restricting the movement of the second brake push rod 6303 in the vertical direction of the second fixed base 31; the lower part of the second brake brake pad 6304 is fixedly connected to the upper part of the second brake push rod 6303 by screws, and the upper part of the second brake brake pad 6304 cooperates with the second rotating rod 32, and the second rotating rod 32 can be locked in any position; the lower part of the second brake push rod 6303 is a long trapezoidal structure, and the upper part is a cylindrical structure.

[0061] The end of the third link in the triangular link 6102 is connected to one end of the third secondary link 61033 by a fifth short pin shaft 61045 to form a sixteenth revolute pair; the other end of the third secondary link 61033 is connected to the third brake slider 6401 by a sixth short pin shaft 61046 to form a seventeenth revolute pair; the third brake slider guide rail 6701 is fixedly connected to the third fixed base 41 by screws and cooperates with the third brake slider 6401 to form a thirteenth prismatic pair, enabling the third brake slider 6401 to move horizontally along the bottom end of the third fixed base 41; the third brake slider 6401 is a trapezoidal rod, and a fourth chute 6402 is provided on the upper part, which cooperates with the lower part of the third brake push rod 6403 to form a fourteenth prismatic pair, converting the horizontal movement of the third brake slider 6401 into the vertical movement of the third brake push rod 6403; the third brake push rod guide rail 6702 is fixedly connected to the third fixed base 41 by screws and cooperates with the third brake push rod 6403 to form a fifteenth prismatic pair, restricting the movement of the third brake push rod 6403 in the vertical direction of the third fixed base 41; the lower part of the third brake brake pad 6404 is fixedly connected to the upper part of the third brake push rod 6403 by screws, and the upper part of the third brake brake pad 6404 cooperates with the third rotating rod 42, and the third rotating rod 42 can be locked in any position; the lower part of the third brake push rod 6403 is of a long trapezoidal structure, and the upper part is of a cylindrical structure.

[0062] As Figures 8 to 10 shown, the main test object of a foot-type robot stability test device based on an underactuated multi-loop mechanism provided by the present invention is a foot-type robot, including a biped robot, a quadruped robot, and a hexapod robot. The test method is to load this device onto the body of a biped robot, a quadruped robot, or a hexapod robot, and generally fix this device to the robot body by screws. According to the stability requirements of different types and specifications of foot-type robots, adjust the direction and magnitude of the disturbing torque of this mobile robot stability test device based on an underactuated multi-loop mechanism. If the foot-type robot can still maintain sufficient stable motion characteristics under this disturbing torque, it proves that the motion stability of this foot-type robot is good and can meet the design requirements. In particular, the random disturbing torque that this device can generate can well test the motion stability performance of the foot-type robot in a complex disturbance environment.

[0063] The key to the movement of the mobile robot stability test device based on the underactuated multi-loop mechanism lies in the coincidence of axes; specifically: the axes at the upper end of the first rotating rod 22, the axes at the lower end of the first rotating rod 22, the axis of the first cylindrical rod 24, and the center position of the first arc rod 25 in the first underactuated link mechanism 2 intersect at one point, that is, at the center of gravity of the moving platform 51; the axes at the upper end of the second rotating rod 32, the axes at the lower end of the second rotating rod 32, the axis of the second cylindrical rod 34, and the center position of the second arc rod 35 in the second underactuated link mechanism 3 intersect at one point; the axes at the upper end of the third rotating rod 42, the axes at the lower end of the third rotating rod 42, the axis of the third cylindrical rod 44, and the center position of the third arc rod 45 in the third underactuated link mechanism 4 intersect at one point.

[0064] When it is necessary to test the stability of the robot under unknown random disturbances, the loop system of the synchronous locking mechanism 6 does not participate in the work. Under the action of gravity, the bottom of the first braking push rod 6203 contacts the first fixed base 21, and at the same time, the inclined surface of the first braking push rod 6203 remains in contact with the inclined surface of the first braking slider 6201. The bottom of the second braking push rod 6303 contacts the second fixed base 31, and at the same time, the inclined surface of the second braking push rod 6303 remains in contact with the inclined surface of the second braking slider 6301. The bottom of the third braking push rod 6403 contacts the third fixed base 41, and at the same time, the inclined surface of the third braking push rod 6403 remains in contact with the inclined surface of the third braking slider 6401. At this time, by setting the parameters of the flywheel adjustment mechanism 5, such as the rotation speed of the servo motor 53, the weight and position of the eccentric block 56, and the height of the flywheel 54, etc., the disturbing torque generated by the flywheel 54 is adjusted. The disturbing torque is then converted into a random disturbing torque with randomly changing magnitude and direction through the first underactuated link mechanism 2, the second underactuated link mechanism 3, and the third underactuated link mechanism 4. The random disturbing torque is transmitted to the object under test (legged robot) through the base 1. For legged robots of different specifications, appropriate parameters are adjusted to make the device generate the random disturbing torque required for testing, so as to test the movement stability of the legged robot in all directions.

[0065] When it is necessary to test the stability of the robot in a certain determined direction, it is necessary to change it into a fixed frame mechanism; first, adjust the angular position of the first rotating rod 22 under the cooperation of the first rotating pair. The first rotating rod 22 drives the first cylindrical rod 24 and the first arc-shaped rod 25 to deflect the same angle synchronously under the cooperation of the second rotating pair. Under the cooperation of the third rotating pair, the moving platform 51 and the flywheel 54 are deflected towards the direction to be tested. At the same time, adjust the angular position of the second rotating rod 32 under the cooperation of the fourth rotating pair. The second rotating rod 32 drives the second cylindrical rod 34 and the second arc-shaped rod 35 to deflect the same angle synchronously under the cooperation of the fifth rotating pair. Under the cooperation of the sixth rotating pair, the moving platform 51 and the flywheel 54 are deflected towards the direction to be tested. At the same time, adjust the angular position of the third rotating rod 42 under the cooperation of the seventh rotating pair. The third rotating rod 42 drives the third cylindrical rod 44 and the third arc-shaped rod 45 to deflect the same angle synchronously under the cooperation of the eighth rotating pair. Under the cooperation of the ninth rotating pair, the moving platform 51 and the flywheel 54 are deflected towards the direction to be tested; secondly, the stepping motor 6101 of the synchronous locking mechanism 6 drives the triangular connecting rod 6102 to make a rotational movement under the cooperation of the eleventh rotating pair. Under the cooperation of the twelfth rotating pair, the triangular connecting rod 6102 drives the first secondary rod 61031 to move. The first secondary rod 61031 drives the first braking slider 6201 to move horizontally on the first braking slider guide rail 6501 through the seventh moving pair under the cooperation of the thirteenth rotating pair. At the same time, under the cooperation of the fourteenth rotating pair, the triangular connecting rod 6102 drives the second secondary rod 61031 to move. The second secondary rod 61031 drives the second braking slider 6201 to move horizontally on the second braking slider guide rail 6501 through the tenth moving pair under the cooperation of the fifteenth rotating pair. At the same time, under the cooperation of the sixteenth rotating pair, the triangular connecting rod 6102 drives the third secondary rod 61031 to move. The third secondary rod 61031 drives the second braking slider 6201 to move horizontally on the second braking slider guide rail 6501 through the thirteenth moving pair under the cooperation of the seventeenth rotating pair;Then, with the cooperation of the eighth translation pair, the first braking slider 6201 pushes the first braking push rod 6203 to move vertically on the first braking push rod guide rail 6502 through the ninth translation pair. At the same time, with the cooperation of the eleventh translation pair, the second braking slider 6201 pushes the second braking push rod 6203 to move vertically on the second braking push rod guide rail 6502 through the twelfth translation pair. At the same time, with the cooperation of the fourteenth translation pair, the third braking slider 6201 pushes the third braking push rod 6203 to move vertically on the third braking push rod guide rail 6502 through the fifteenth translation pair. Finally, the first braking brake pad 6204 fixedly connected to the first braking push rod 6203 contacts the first rotating rod 22 under the push of the first braking push rod 6203. At the same time, the second braking brake pad 6204 fixedly connected to the second braking push rod 6203 contacts the second rotating rod 32 under the push of the second braking push rod 6203. At the same time, the third braking brake pad 6204 fixedly connected to the third braking push rod 6203 contacts the third rotating rod 42 under the push of the third braking push rod 6203. Under the action of friction, the first rotating rod 22, the second rotating rod 32 and the third rotating rod 42 are locked at a preset angular position.

[0066] When the synchronous locking mechanism 6 locks the first rotating rod 22, the second rotating rod 32, and the third rotating rod 42, the triangular connecting rod 6102, the first secondary connecting rod 61031, the second secondary connecting rod 61032, the third secondary connecting rod 61033, and the first braking slider 6201, the second braking slider 6301, and the third braking slider 6401 are on the same straight line. At this time, the transmission angle between the triangular connecting rod 6102 and the first secondary connecting rod 61031, the second secondary connecting rod 61032, and the third secondary connecting rod 61033 is 0, so that the first braking slider 6201 pushes the first braking push rod 6203 to drive the first braking brake pad 6204 to lock the first rotating rod 22. At the same time, the second braking slider 6201 pushes the second braking push rod 6203 to drive the second braking brake pad 6204 to lock the second rotating rod 32. At the same time, the third braking slider 6201 pushes the third braking push rod 6203 to drive the third braking brake pad 6204 to lock the third rotating rod 42. The synchronous locking mechanism 6 will not become unstable and cause braking failure due to the disturbing torque generated by the flywheel 54. When it is necessary to adjust the locking angle of the rotating rod 22, only need to rotate the stepping motor 6101 to get out of the dead point position and the braking state. After the first rotating rod 22, the second rotating rod 32, and the third rotating rod 42 are adjusted to the new target angle, repeat the above steps to lock the first rotating rod 22, the second rotating rod 32, and the third rotating rod 42.

[0067] When it is necessary to test the stability performance of the robot under different disturbance magnitudes, this device provides a random disturbance torque to the robot by adjusting the height, rotation speed, eccentric position, and mass of the flywheel 54, and uses the generated random disturbance torque to judge the stability of the robot.

[0068] If it is necessary to increase the height of the flywheel 54, press the first fixed buckle 52031, the second fixed buckle 52032, the third fixed buckle 52033, and the fourth fixed buckle 52034 around the height adjustment mechanism 52. Under the cooperation of the first spring 52021, the second spring 52022, the third spring 52023, the fourth spring 52024, and the height adjustment table 5201, through the third moving pair, the first fixed buckle 52031, the second fixed buckle 52032, the third fixed buckle 52033, and the fourth fixed buckle 52034 contract towards the inner side of the notch of the height adjustment table 5201, and at the same time, lift the flywheel 54 upwards. Since the flywheel 54 is fixedly connected to the servo motor 53, and the servo motor 53 is fixedly connected to the height adjustment mechanism 52, the height adjustment structure 52 can be lifted upwards. The adjustable height range of the height adjustment mechanism 52 is related to the spacing and quantity of the adjustment holes 5102 on the moving platform 51. After adjusting to the required height, release the first fixed buckle 52031, the second fixed buckle 52032, the third fixed buckle 52033, and the fourth fixed buckle 52034 to make them cooperate with the adjustment holes 5102, and fix the height adjustment mechanism 52 and the flywheel 54 at a certain height; similarly, if you want to further increase the height of the flywheel 54, continue to adjust according to the above method, and the adjustable limit height is the limit hole position height of the adjustment holes 5102. Under the condition of not changing the eccentric mass and rotation speed.

[0069] If it is necessary to lower the height of the flywheel 54, only slightly press the first fixed buckle 52031, the second fixed buckle 52032, the third fixed buckle 52033, and the fourth fixed buckle 52034 around the height adjustment mechanism 52. Under the cooperation of the first spring 52021, the second spring 52022, the third spring 52023, the fourth spring 52024, and the height adjustment table 5201, through the third moving pair, the first fixed buckle 52031, the second fixed buckle 52032, the third fixed buckle 52033, and the fourth fixed buckle 52034 contract towards the inner side of the notch of the height adjustment table 5201, and at the same time, press the flywheel 54 downwards. Since the structure of the fixed buckle is a trapezoidal structure with the short side below, only a slight press is required. Under the cooperation of the first fixed buckle 52031, the second fixed buckle 52032, the third fixed buckle 52033, and the fourth fixed buckle 52034 and the adjustment holes 5102, the height of the height adjustment mechanism 52 and the flywheel 54 can be lowered. Similarly, if you want to further lower the height of the flywheel 54, continue to adjust according to the above method, and the adjustable limit height is the limit hole position height of the adjustment holes 5102.

[0070] To change the rotational speed of the flywheel 54, only the rotational speed of the servo motor 53 needs to be adjusted. Without changing the height, eccentric position, and mass of the flywheel 54, if the rotational speed of the servo motor 53 is increased, the disturbing torque can be increased; similarly, without changing the height, eccentric position, and mass of the flywheel 54, if the rotational speed of the servo motor 53 is decreased, the disturbing torque can be decreased.

[0071] If it is necessary to change the eccentric position of the flywheel 54, first adjust the position of the eccentric block 56 in the first chute 55, and then fix the eccentric block 56 in the first chute 55 with the adjusting screw 57; with the cooperation of the second moving pair, if the eccentric block 56 is adjusted in the direction away from the center of the flywheel 54, without changing the height, rotational speed, and mass of the eccentric block 56 of the flywheel 54, the moment of inertia of the flywheel adjusting mechanism 5 can be increased, thereby increasing the disturbing torque; similarly, with the cooperation of the second moving pair, if the eccentric block 56 is adjusted in the direction closer to the center of the flywheel 54, without changing the height, rotational speed, and mass of the flywheel 54, the moment of inertia of the flywheel adjusting mechanism 5 can be decreased, thereby decreasing the disturbing torque; if it is necessary to change the eccentric mass of the flywheel 54, only the mass of the eccentric block 55 needs to be changed. Without changing the height, rotational speed, and position of the mass block of the flywheel 54, if the mass of the eccentric block 55 is increased, the disturbing torque can be increased; similarly, without changing the height, rotational speed, and position of the mass block of the flywheel 54, if the mass of the eccentric block 55 is decreased, the disturbing torque can be decreased.

[0072] For the case where a larger disturbing torque is required, the above-mentioned methods of increasing the disturbing torque can be used in combination. For example, while increasing the rotational speed of the flywheel 54, the mass and eccentric radius of the eccentric block 56 are increased, so that a greater disturbing torque is generated.

[0073] The specific working process of the present invention is as follows:

[0074] For the stability test device of the legged robot based on the underactuated multi-loop mechanism, it has the advantages of variable structure, diverse functions, adjustable parameters, etc., and can be applied to the stability test of legged robots in various test environments.

[0075] When it is necessary to test the stability of the robot under unknown random disturbances, the loop system of the synchronous locking mechanism 6 does not participate in the work. Under the action of gravity, the bottom of the braking push rod 6203 contacts the fixed base 21, and at the same time, the inclined surface of the braking push rod 6203 remains in contact with the inclined surface of the braking slider 6201. At this time, by setting the parameters of the flywheel adjustment mechanism 5, such as the rotation speed of the servo motor 53, the weight and position of the eccentric block 56, and the height of the flywheel 54, etc., the disturbing torque generated by the flywheel 54 is adjusted. The disturbing torque is then converted into a random disturbing torque with randomly changing magnitude and direction through the first underactuated link mechanism 2, the second underactuated link mechanism 3, and the third underactuated link mechanism 4. The random disturbing torque is transmitted to the robot under test through the base 1 connected to the robot under test. For foot-type robots of different specifications, appropriate parameters are adjusted to make the device generate the torque required for testing, so as to test the motion stability of the foot-type robot in all directions.

[0076] When it is necessary to test the stability of the robot in a certain determined direction, this underactuated multi-loop mechanism needs to be changed into a fixed frame mechanism; first, adjust the angular positions of the first rotating rod 22, the second rotating rod 32, and the third rotating rod 42 to make the moving platform 51 and the flywheel 54 bias towards the direction to be tested. Secondly, the stepping motor 6101 of the synchronous locking mechanism 6 drives the triangular link 6102 to make a rotational motion. At the same time, the triangular link 6102 drives the first secondary link 61031, the second secondary link 61032, the third secondary link 61033 and the connected first braking slider 6201, the second braking slider, and the third braking slider to move horizontally on the first braking slider guide rail 6501, the second braking slider guide rail, and the third braking slider guide rail respectively. Then, the first braking slider 6201, the second braking slider, and the third braking slider respectively push the first braking push rod 6203, the second braking push rod, and the third braking push rod to move vertically on the first braking push rod guide rail 6502, the second braking push rod guide rail, and the third braking push rod guide rail respectively. Finally, the first braking brake pad 6204, the second braking brake pad, and the third braking brake pad fixedly connected to the first braking push rod 6203, the second braking push rod, and the third braking push rod respectively contact the first rotating rod 22, the second rotating rod 32, and the third rotating rod 42, and lock the first rotating rod 22, the second rotating rod 32, and the third rotating rod 42 at the preset angular positions under the action of friction. At this time, this device is a fixed frame mechanism, and the disturbing torque generated by the flywheel 54 is transmitted to the robot under test through the fixed frame mechanism, so as to test the anti-disturbance ability of the robot in this direction. Similarly, both the test direction and the magnitude of the disturbing torque can be adjusted through the cooperation of the first underactuated link mechanism 2, the second underactuated link mechanism 3, the third underactuated link mechanism 4, the flywheel adjustment mechanism 5, and the synchronous locking mechanism 6.

[0077] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A stability test device for a legged robot based on an underactuated multi-loop mechanism, characterized in that, The device includes a base (1), a first underactuated linkage mechanism (2), a second underactuated linkage mechanism (3), a third underactuated linkage mechanism (4), a flywheel adjustment mechanism (5), and a synchronous locking mechanism (6); One end of the first underactuated linkage mechanism (2), the second underactuated linkage mechanism (3), and the third underactuated linkage mechanism (4) is fixedly connected to the base (1) by screws respectively, and the other ends are respectively connected to the bottom of the flywheel adjustment mechanism (5), and are evenly distributed around the base (1); the flywheel adjustment mechanism (5) is located at the central position of the biped robot stability test device based on the underactuated multi-loop mechanism; one end of the synchronous locking mechanism (6) is connected to the base (1), and the other end is respectively connected to the first underactuated linkage mechanism (2), the second underactuated linkage mechanism (3), and the third underactuated linkage mechanism (4); The flywheel adjustment mechanism (5) is used to generate an adjustable disturbing torque and transmit it to the first underactuated linkage mechanism (2), the second underactuated linkage mechanism (3), and the third underactuated linkage mechanism (4); The first underactuated linkage mechanism (2), the second underactuated linkage mechanism (3), and the third underactuated linkage mechanism (4) are respectively used to randomize the disturbing torque and conduct it to the base (1); The synchronous locking mechanism (6) is used to fix the first underactuated linkage mechanism (2), the second underactuated linkage mechanism (3), and the third underactuated linkage mechanism (4) at any position.

2. The stability testing device for a legged robot based on an underactuated multi-loop mechanism according to claim 1, characterized in that, The first underactuated linkage mechanism (2) is composed of a first fixed base (21), a first rotating rod (22), a first base connecting shaft (23), a first cylindrical rod (24), a first arc-shaped rod (25), a first rotating rod connecting shaft (26), and a first moving platform connecting shaft (27); the first fixed base (21) is an L-shaped rod, the lower part of the first fixed base (21) is fixedly connected to the base (1) by screws, and the upper part of the first fixed base (21) is connected to the upper part of the first rotating rod (22) through the first base connecting shaft (23) to form a first rotating pair; the lower part of the first rotating rod (22) is connected to the lower end of the first cylindrical rod (24) through the first rotating rod connecting shaft (26) to form a second rotating pair; the upper end of the first cylindrical rod (24) is fixedly connected to the lower end of the first arc-shaped rod (25) by screws; the upper end of the first arc-shaped rod (25) is connected to the flywheel adjustment mechanism (5) through the first moving platform connecting shaft (27) to form a third rotating pair; The second underactuated linkage mechanism (3) consists of a second fixed base (31), a second rotating rod (32), a second base connecting shaft (33), a second cylindrical rod (34), a second arc-shaped rod (35), a second rotating rod connecting shaft (36), and a second moving platform connecting shaft (37); the second fixed base (31) is an L-shaped rod, the lower part of the second fixed base (31) is fixedly connected to the base (1) by screws, and the upper part of the second fixed base (31) is connected to the upper part of the second rotating rod (32) through the second base connecting shaft (33) to form a fourth rotating pair; the lower part of the second rotating rod (32) is connected to the lower end of the second cylindrical rod (34) through the second rotating rod connecting shaft (36) to form a fifth rotating pair; the upper end of the second cylindrical rod (34) is fixedly connected to the lower end of the second arc-shaped rod (35) by screws; the upper end of the second arc-shaped rod (35) is connected to the flywheel adjustment mechanism (5) through the second moving platform connecting shaft (37) to form a sixth rotating pair; The third underactuated linkage mechanism (4) consists of a third fixed base (41), a third rotating rod (42), a third base connecting shaft (43), a third cylindrical rod (44), a third arc-shaped rod (45), a third rotating rod connecting shaft (46), and a third moving platform connecting shaft (47); the third fixed base (41) is an L-shaped rod, the lower part of the third fixed base (41) is fixedly connected to the base (1) by screws, and the upper part of the third fixed base (41) is connected to the upper part of the third rotating rod (42) through the third base connecting shaft (43) to form a seventh rotating pair; the lower part of the third rotating rod (42) is connected to the lower end of the third cylindrical rod (44) through the third rotating rod connecting shaft (46) to form an eighth rotating pair; the upper end of the third cylindrical rod (44) is fixedly connected to the lower end of the third arc-shaped rod (45) by screws; the upper end of the third arc-shaped rod (45) is connected to the flywheel adjustment mechanism (5) through the third moving platform connecting shaft (47) to form a ninth rotating pair.

3. The stability testing device for a legged robot based on an underactuated multi-loop mechanism according to claim 2, characterized in that, The flywheel adjustment mechanism (5) consists of a moving platform (51), a height adjustment mechanism (52), a servo motor (53), a flywheel (54), an eccentric block (56), and an adjustment screw (57). The moving platform (51) consists of a moving platform body (5101), an adjustment hole (5102), a first mounting boss (5103), a second mounting boss (5104), and a third mounting boss (5105); the moving platform body (5101) is a hollow cylindrical structure; the first mounting boss (5103), the second mounting boss (5104), and the third mounting boss (5105) are respectively fixedly connected to the moving platform body (5101) by screws and are evenly distributed at the lower part of the moving platform body (5101); the first mounting boss (5103) is connected to the first arc-shaped rod (25) by a first moving platform connecting shaft (27) to form a third rotating pair; the second mounting boss (5104) is connected to the second arc-shaped rod (35) by a second moving platform connecting shaft (37) to form a sixth rotating pair; the third mounting boss (5105) is connected to the third arc-shaped rod (45) by a third moving platform connecting shaft (47) to form a ninth rotating pair. The upper part of the height adjustment mechanism (52) is fixedly connected to the servo motor (53) by screws. The height adjustment mechanism (52) cooperates with the moving platform (51) through the adjustment hole (5102) to form a first translation pair; the upper part of the servo motor (53) cooperates with the flywheel (54) to form a tenth rotating pair; a first chute (55) is provided on the upper part of the flywheel (54) to cooperate with the eccentric block (56) to form a second translation pair; the adjustment screw (57) cooperates with the eccentric block (56) to fix the eccentric block (56) in the first chute (55).

4. A stability testing device for a legged robot based on an underactuated multi-loop mechanism according to claim 3, characterized in that, The height adjustment mechanism (52) consists of a height adjustment table (5201), a first spring (52021), a second spring (52022), a third spring (52023), a fourth spring (52024), a first fixed buckle (52031), a second fixed buckle (52032), a third fixed buckle (52033), and a fourth fixed buckle (52034); the height adjustment table (5201) is a cylindrical structure, and a first notch, a second notch, a third notch, and a fourth notch are evenly provided around it; the lower part of the first fixed buckle (52031) expands and contracts along the direction of the first notch through the first spring (52021) to form a third translation pair; the lower part of the second fixed buckle (52032) expands and contracts along the direction of the second notch through the second spring (52022) to form a fourth translation pair; the lower part of the third fixed buckle (52033) expands and contracts along the direction of the third notch through the third spring (52023) to form a fifth translation pair; the lower part of the fourth fixed buckle (52034) expands and contracts along the direction of the fourth notch through the fourth spring (52024) to form a sixth translation pair.

5. The stability testing device for a legged robot based on an underactuated multi-loop mechanism according to claim 1, characterized in that The synchronous locking mechanism (6) includes a driving mechanism (61), a first braking mechanism (62), a second braking mechanism (63), a third braking mechanism (64), a first fixed guide rail (65), a second fixed guide rail (66), and a third fixed guide rail (67); the driving mechanism (61) is fixed at the center of the base (1); the upper part of the first braking mechanism (62) is connected to the first underactuated link mechanism (2), the upper part of the second braking mechanism (63) is connected to the second underactuated link mechanism (3), and the upper part of the third braking mechanism (64) is connected to the third underactuated link mechanism (4); the lower parts of the first braking mechanism (62), the second braking mechanism (63), and the third braking mechanism (64) are respectively connected to one end of the driving mechanism (61), and the other end of the driving mechanism (61) is fixed at the center of the base (1); the first fixed guide rail (65) is respectively connected to the first braking mechanism (62) and the first underactuated link mechanism (2); the second fixed guide rail (66) is respectively connected to the second braking mechanism (63) and the second underactuated link mechanism (3); the third fixed guide rail (67) is respectively connected to the third braking mechanism (64) and the third underactuated link mechanism (4).

6. The foot-type robot stability testing device based on an underactuated multi-loop mechanism according to claim 5, wherein The driving mechanism (61) includes a stepping motor (6101), a triangular link (6102), a first secondary link (61031), a second secondary link (61032), a third secondary link (61033), a first short pin shaft (61041), a second short pin shaft (61042), a third short pin shaft (61043), a fourth short pin shaft (61044), a fifth short pin shaft (61045), and a sixth short pin shaft (61046); the first braking mechanism (62) includes a first braking slider (6201), a second chute (6202), a first braking push rod (6203), and a first braking brake pad (6204); the second braking mechanism (63) includes a second braking slider (6301), a third chute (6302), a second braking push rod (6303), and a second braking brake pad (6304); the third braking mechanism (64) includes a third braking slider (6401), a fourth chute (6402), a third braking push rod (6403), and a third braking brake pad (6404); the first fixed guide rail (65) is composed of a first braking slider guide rail (6501) and a first braking push rod guide rail (6502); the second fixed guide rail (66) is composed of a second braking slider guide rail (6601) and a second braking push rod guide rail (6602); the third fixed guide rail (67) is composed of a third braking slider guide rail (6701) and a third braking push rod guide rail (6702); The lower part of the stepping motor (6101) is fixedly connected to the base (1) by screws, and the upper part is connected to the center of the triangular link (6102) to form an eleventh rotating pair; The end of the first link in the triangular link (6102) is connected to one end of the first two-stage link (61031) by a first short pin shaft (61041) to form a twelfth rotating pair; the other end of the first two-stage link (61031) is connected to the first brake slider (6201) by a second short pin shaft (61042) to form a thirteenth rotating pair; the first brake slider guide rail (6501) is fixedly connected to the first fixed base (21) by screws and cooperates with the first brake slider (6201) to form a seventh sliding pair; the first brake slider (6201) is a trapezoidal rod, and a second chute (6202) is provided on the upper part, and the second chute (6202) cooperates with the lower part of the first brake push rod (6203) to form an eighth sliding pair; the first brake push rod guide rail (6502) is fixedly connected to the first fixed base (21) by screws and cooperates with the first brake push rod (6203) to form a ninth sliding pair; the lower part of the first brake brake pad (6204) is fixedly connected to the upper part of the first brake push rod (6203) by screws, and the upper part of the first brake brake pad (6204) cooperates with the first rotating rod (22) to lock the first rotating rod (22) in any position; the lower part of the first brake push rod (6203) is a long trapezoidal structure, and the upper part is a cylindrical structure; The end of the second link in the triangular link (6102) is connected to one end of the second two-stage link (61032) by a third short pin shaft (61043) to form a fourteenth rotating pair; the other end of the second two-stage link (61032) is connected to the second brake slider (6301) by a fourth short pin shaft (61044) to form a fifteenth rotating pair; the second brake slider guide rail (6601) is fixedly connected to the second fixed base (31) by screws and cooperates with the second brake slider (6301) to form a tenth sliding pair; the second brake slider (6301) is a trapezoidal rod, and a third chute (630) is provided on the upper part, and the third chute (6302) cooperates with the lower part of the second brake push rod (6303) to form an eleventh sliding pair; the second brake push rod guide rail (6602) is fixedly connected to the second fixed base (31) by screws and cooperates with the second brake push rod (6303) to form a twelfth sliding pair; the lower part of the second brake brake pad (6304) is fixedly connected to the upper part of the second brake push rod (6303) by screws, and the upper part of the second brake brake pad (6304) cooperates with the second rotating rod (32) to lock the second rotating rod (32) in any position; the lower part of the second brake push rod (6303) is a long trapezoidal structure, and the upper part is a cylindrical structure; The end of the third link in the triangular link (6102) is connected to one end of the third secondary link (61033) by a fifth short pin shaft (61045) to form a sixteenth revolute pair; the other end of the third secondary link (61033) is connected to the third brake slider (6401) by a sixth short pin shaft (61046) to form a seventeenth revolute pair; the third brake slider guide rail (6701) is fixedly connected to the third fixed base (41) by screws and cooperates with the third brake slider (6401) to form a thirteenth prismatic pair; the third brake slider (6401) is a trapezoidal rod, and a fourth chute (6402) is provided on the upper part, and the fourth chute (6402) cooperates with the lower part of the third brake push rod (6403) to form a fourteenth prismatic pair; the third brake push rod guide rail (6702) is fixedly connected to the third fixed base (41) by screws and cooperates with the third brake push rod (6403) to form a fifteenth prismatic pair; the lower part of the third brake brake pad (6404) is fixedly connected to the upper part of the third brake push rod (6403) by screws, and the upper part of the third brake brake pad (6404) cooperates with the third rotating rod (42) to lock the third rotating rod (42) in any position; the lower part of the third brake push rod (6403) is a long trapezoidal structure, and the upper part is a cylindrical structure.

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