CN110481668A - A kind of adaptive strain posture bionic mechanical foot - Google Patents

Abstract

The invention discloses an adaptive attitude-variable bionic mechanical foot, which can passively adjust the movement attitude of the toes in real time according to the ground environment where it is located, and change the contact area of the sole of the foot. It includes a load-bearing rod, a guide rod, a first slider linkage mechanism, a second slider linkage mechanism, a first toe mechanism, a second toe mechanism, and a third toe mechanism; the guide rod passes through the load-bearing rod, the second toe mechanism in sequence A slider link mechanism and a second slider link mechanism are screwed to the first toe mechanism; a pair of second toe mechanisms are respectively hinged on the left and right sides of the first toe mechanism; a pair of third toe mechanisms The mechanisms are respectively hinged on the outside of the second toe mechanism on the corresponding side; the two ends of the first slider linkage mechanism are respectively hinged to the third toe mechanism on the corresponding side; the two ends of the second slider linkage mechanism are respectively connected to the corresponding side The second toe mechanism is hinged; the guide bar is sleeved with a spring; the toe mechanism is composed of a phalange, a foot pad unit and a sole.

Description

A self-adaptive posture-changing bionic mechanical foot

technical field

The invention belongs to the technical field of engineering bionics, and in particular relates to a self-adaptive posture-changing bionic mechanical foot.

Background technique

Compared with wheel-type and crawler-type mobile mechanisms, the contact points of leg-foot-type mobile mechanisms are discrete and discontinuous when passing on soft ground, and its traction performance, sand-surfing performance and anti-subsidence performance are all significantly improved. As the main actuator of the leg-foot mobile mechanism, the design of its structure, shape and function will directly affect whether the mobile mechanism can pass smoothly and normally on soft ground. The feet of most humanoid robots are flat and approximately rectangular, such as ASIMO and PETMAN. If a legged robot is to walk on rough terrain, its feet are usually designed to be cylindrical or spherical so that they can adapt to the terrain more freely, for example, BigDog, LS3, LittleDog, etc. Some robots have irregularly shaped feet, especially when they are designed from a bionic perspective, such as the curved feet (C-shaped) of the Sandbot robot. However, the foot structures of these robots are fixed and cannot be adjusted in real time according to the terrain environment in order to better resist subsidence, provide traction and energy storage and vibration reduction.

An adult ostrich weighs 60-160kg, runs at a continuous speed of 50-60 km/h for about 30 minutes, and sprints at a speed of over 70 km/h. It is the fastest biped bird on land. The two-toed foot of an ostrich is the main actuator during high-speed running, and it plays an important role in providing traction, reducing subsidence, storing energy, and cushioning vibration. The third toe is the main weight-bearing toe and the fourth toe is the auxiliary support toe. The movement of the ostrich toes is mainly driven by the extensor and flexor tendons connected to the phalanges. Taking the third toe as an example, the toe extension movement of different phalanges is controlled by different extensor tendons that connect the dorsum of the toe to different phalanges, while the toe flexion movement of different phalanges is controlled by different flexor tendons that connect the bottom of the toe to different phalanges to control. In addition to connecting and driving the phalanges, the permanent ground-off function of the metatarsophalangeal joint is primarily the function of the tensed tendons. The tendon is wavy at the proximal and distal ends of the metatarsophalangeal joint, similar to the shape and function of a spring, which plays an important role in the energy storage and vibration reduction of the ostrich foot.

Chinese invention patent of a mechanical leg imitating ostrich hind limbs (application number: 201610604950.4). The phalanges of the feet are connected by torsion springs. When the mechanical foot is off the ground, the phalanxes of the feet return to their original state passively with the help of the restoring force of the torsion springs. , not considering the coordination of different extensor/flexor tendons and phalanxes of ostrich feet to achieve toe extension/flexion respectively.

A Chinese invention patent for an adaptive sand bionic mechanical foot (application number: 201610996333.3) focuses on the separation and closure of the two toes. The ground environment can be adjusted passively and adaptively.

A Chinese invention patent of a bionic tendon-bone synergistic rigid-flexible coupling mechanical foot for crossing the sand (application number: 201810786878.0) separates the phalanges of the main toe and the auxiliary toe, emphasizing the push-off function of the mechanical foot, through the servo motor push rod, cushioning and reducing The separation and closing of the two toes is achieved through the cooperation of the vibration mechanism and the flexible passive control mechanism. There is no detailed consideration of the different extensor/flexor tendons driving the toe extension/flexion movements of different phalanges and the movement posture of the toes in different contact periods. The adjustment, and the need for servo motor assistance, is not completely passive.

Contents of the invention

In order to solve the above-mentioned problems existing in the prior art, the present invention provides an adaptive bionic mechanical foot with variable posture, which imitates the function of the metatarsophalangeal joint of the ostrich foot, the movement posture of the phalanx in different contact periods, The ratio of the elastic modulus of the soft tissue of the foot pad, the assembly sequence, and the shape of the sole of the foot. Improve the advantages of traction, energy storage and buffering and vibration reduction, so as to improve the passing performance, energy saving performance and stability performance of the robot on soft ground.

The purpose of the present invention is achieved through the following technical solutions:

An adaptive posture-changing bionic mechanical foot, comprising a load-bearing rod, a guide rod, a first slider linkage mechanism, a second slider linkage mechanism, a first toe mechanism, a pair of second toe mechanisms, a pair of first toe mechanisms Three-toe mechanism; the guide rod passes through the load-bearing rod, the first slider linkage mechanism and the second slider linkage mechanism in turn, and is threadedly connected with the first toe mechanism; a pair of second toe mechanisms are respectively hinged on the second toe mechanism. The left and right sides of a toe mechanism; a pair of third toe mechanisms are respectively hinged on the outside of the second toe mechanism on the corresponding side; the two ends of the first slider link mechanism are respectively hinged to the third toe mechanism on the corresponding side; The two ends of the second slider link mechanism are respectively hinged with the second toe mechanism on the corresponding side; the first spring is sleeved on the guide bar section between the load-bearing bar and the first slider link mechanism; the first A second spring is sleeved on the guide rod segment between the slider linkage mechanism and the second slider linkage mechanism; a second spring is sleeved on the guide rod segment between the second slider linkage mechanism and the first toe mechanism. third spring.

Further, the first toe mechanism, the second toe mechanism, and the third toe mechanism are all composed of phalanges, foot pad units and soles; the foot pad units are pasted under the phalanges, and the soles are pasted on the feet. Under the pad unit; the first toe mechanism, the second toe mechanism, and the third toe mechanism are hinged through the phalanges; the second toe mechanism is hinged with the second slider linkage through its phalanges, and the third toe The external mechanism is hinged with the first slider link mechanism through its phalanx.

Further, the foot pad unit is composed of the foot pad unit toe pad layer, the foot pad unit fascia layer and the foot pad unit skin layer from top to bottom, and the foot pad unit toe pad layer, the foot pad unit fascia layer and the The skin layer of the foot pad unit is made of silicone rubber with different hardness, and the hardness ratio of the silicone rubber is 3:7:11.

Further, the sole of the foot is made of photosensitive resin material and processed by 3D printing technology.

Further, the first slider link mechanism includes a first slider and two first connecting rods, one first connecting rod is respectively hinged at both ends of the first slider, and the other ends of the two first connecting rods are respectively It is hinged with the outside of the third toe mechanism; the second slider linkage mechanism includes a second slider and two second connecting rods, the two ends of the second slider are respectively hinged with a second connecting rod, and two second connecting rods The other end of each is hinged with the outside of the second toe mechanism.

An adaptive posture-changing bionic mechanical foot of the present invention has the following beneficial effects:

The invention is based on the engineering bionic principle, adopts engineering bionic technology, and uses the third toe of the ostrich foot as a bionic prototype to design a completely passive dynamic adjustment of the movement posture of the toe according to the current soft ground environment. First of all, using connecting rods, sliders, springs, load-bearing rods, guide rods, etc. to imitate the different extensor/flexor tendon connections inside the ostrich foot and to drive the toe extension/flexion functions of different phalanges, so that the mechanical foot can move in different contact periods. It has different sports postures, which changes the ground contact area, realizes the functions of reducing subsidence and energy saving; secondly, the elastic modulus ratio and assembly of ostrich toe pads, fascia and skin soft tissues are imitated by using silicone rubber with different hardness Sequentially, the hardness ratio of silicone rubber is determined, which realizes the function of cushioning and vibration reduction, and improves stability; finally, the soles of each phalanx imitate the shape of ostrich soles, which reduces the intrusion resistance and realizes sand-fixing and flow-limiting. function, which improves the traction performance of the mechanical foot.

An adaptive posture-changing bionic mechanical foot is structurally symmetrical, which improves the stability of the entire structure and makes the force on the mechanical foot more uniform when it touches the ground, which will significantly enhance the passing performance of the robot when moving on soft ground .

Description of drawings

Fig. 1 is a perspective view of the present invention.

Fig. 2 is a front view of the present invention.

Fig. 3 is a schematic diagram of the linear posture of the mechanical foot when the present invention just touches the ground.

Fig. 4 is a schematic diagram of the self-adaptive posture of the mechanical foot of the present invention in the middle stage of touching the ground or when the robot is stepping.

Fig. 5 is a schematic diagram of the arc posture of the mechanical foot of the present invention when it is off the ground.

Fig. 6 is a partially enlarged view of the present invention.

In the figure: 1- load-bearing rod, 2- guide rod, 3- the first spring, 4- the first slider, 5- the first connecting rod, 6- the second spring, 7- the second slider, 8- the third Spring, 9-the second connecting rod, 10-the first phalanx, 11-the first foot pad unit, 111-the toe pad layer of the first foot pad unit, 112-the fascia layer of the first foot pad unit, 113-the first foot Pad unit skin layer, 12-first plantar, 13-second phalanx, 14-second foot pad unit, 141-second foot pad unit toe pad layer, 142-second foot pad unit fascia layer, 143- Skin layer of the second foot pad unit, 15-second plantar, 16-third phalanx, 17-third foot pad unit, 171-toe pad layer of the third foot pad unit, 172-fascia layer of the third foot pad unit , 173 - skin layer of the third foot pad unit, 18 - third plantar.

Detailed ways

The specific implementation of the bionic mechanical foot will be described below with reference to FIG. 1 to FIG. 6 .

An adaptive posture-changing bionic mechanical foot, comprising a load-bearing rod 1, a guide rod 2, a first slider linkage mechanism, a second slider linkage mechanism, a first toe mechanism, a pair of second toe mechanisms, a on the third toe body. After the guide rod 2 passes through the load-bearing rod 1, the first slider 4 of the first slider linkage mechanism, and the second slider 7 of the second slider linkage mechanism, it is threadedly connected with the first toe mechanism; The second toe mechanism is respectively hinged on the left and right sides of the first toe mechanism; a pair of third toe mechanisms are respectively hinged on the outside of the second toe mechanism on the corresponding side. The ends of the two first connecting rods 5 of the first slider link mechanism are respectively hinged with the third toe mechanism on the corresponding side; The toe mechanism is hinged; the first spring 3 is sleeved on the guide rod 2 section between the load-bearing rod 1 and the first slider linkage mechanism, and the first spring 3 is sleeved between the first slider linkage mechanism and the second slider linkage mechanism. The second spring 6 is sleeved on the 2 sections of the guide rod between the two sections, and the third spring 8 is sleeved on the 2 sections of the guide bar between the second slider linkage mechanism and the first toe mechanism.

The first slider link mechanism includes the first slider 4, two first connecting rods 5; the second slider link mechanism includes the second slider 7, two second connecting rods 9; the first toe mechanism includes The first phalange 10, the first foot pad unit 11, the first sole 12; the second toe mechanism includes the second phalange 13, the second foot pad unit 14, the second sole 15; the third toe mechanism includes the third The phalanx 16 , the third foot pad unit 17 , and the third sole 18 .

After the guide rod 2 passes through the load-bearing rod 1, the first spring 3, the first slider 4, the second spring 6, the second slider 7 and the third spring 8 in sequence, it is connected with the first phalanx 10 by screw connection. The left and right sides of the first phalanx 10 are respectively hinged with a second phalanx 13 . The left side of the left second phalanx 13 is connected with a third phalanx 16 through a hinge, and the right side of the right second phalanx 13 is connected with a third phalanx 16 through a hinge. The two ends of the first connecting rod 5 on the left are respectively hinged with the left side of the first slider 4 and the left side of the third phalanx 16 on the left, and the two ends of the first connecting rod 5 on the right are respectively connected with the right side of the first slider 4 and the left side of the third phalanx 16 on the left. The right side of the right third phalanx 16 is hinged. The two ends of the second connecting rod 9 on the left are respectively hinged with the left side of the second slide block 7 and the left side of the second phalanx 13 on the left, and the two ends of the second connecting rod 9 on the right are respectively connected with the right side and the left side of the second slide block 7. The right side of the right second phalanx 13 is hinged.

The first foot pad unit 11 is made up of the first foot pad unit toe pad layer 111, the first foot pad unit fascia layer 112 and the first foot pad unit skin layer 113; the second foot pad unit 14 is made up of the second foot pad unit toe Cushion layer 141, the second foot pad unit fascia layer 142 and the second foot pad unit skin layer 143; And the third foot pad unit skin layer 173 is formed. For these three foot pad units, from top to bottom, it is composed of foot pad unit toe pad layer, foot pad unit fascia layer and foot pad unit skin layer, and foot pad unit toe pad layer, foot pad unit fascia layer Silicone rubber with different hardness is used for the skin layer of the layer and the foot pad unit respectively, and the hardness ratio of the silicone rubber is 3:7:11. The first foot pad unit 11, the second foot pad unit 14 and the third foot pad unit 17 are respectively pasted under the first phalanx 10, the second phalanx 13 and the third phalanx 16, and their sizes are respectively based on the first phalanx 10, The size of the second phalanx 13 and third phalanx 16 is determined.

The first sole 12, the second sole 15, and the third sole 18 are respectively pasted under the first foot pad unit 11, the second foot pad unit 14, and the third foot pad unit 17, and their sizes are respectively according to the first foot pad unit. The foot pad unit 11, the second foot pad unit 14 and the size of the third foot pad unit 17 are determined. Select photosensitive resin material and 3D printing technology to process the first sole 12 , the second sole 15 and the third sole 18 .

The bionic principle of an adaptive posture-changing bionic mechanical foot:

When the ostrich runs at high speed, the third toe is the main load-bearing toe. When it first touches the ground, the metatarsophalangeal joint that is permanently off the ground is compressed, and its position is lowered. The kinetic energy is converted into elastic potential energy and stored in the metatarsophalangeal joint and tendons. able parts. During this process, the dorsal extensor tendon of the toe is stretched, the flexor tendon at the bottom of the toe is in a natural state, and the entire toe is instantly stretched and in contact with the ground, which increases the contact area with the ground and reduces the instantaneous impact force of the foot . In the middle stage of touching the ground, the stretched dorsal extensor tendon of the toe gradually recovers, and at the same time, the flexor tendon of the plantar toe is gradually stretched. The ostrich controls the movement of each phalanx of the foot through the coordination of the extensor tendon and the flexor tendon. Among them, the long extensor/flexor tendon of the toe is connected with the third phalanx 16 at the far end, respectively controlling the extension/flexion movement of the third phalanx 16; the perforated extension/flexor tendon is connected with the second phalanx 13 in the middle, respectively It controls the toe extension/flexion movement of the second phalanx 13; the foraminal extensor/flexor tendon is connected to the proximal first phalanx 10, and controls the toe extension/flexion movement of the first phalanx 10 respectively. In addition, ostriches do not stand for a long time, but lift and lower their feet intermittently, similar to standing still, commonly known as "unable to stand". When the subsidence of ostrich feet on the sandy surface increases, the frequency of ostrich feet lifting and landing will be higher. Whether it is in the middle of touching the ground or when standing still, the extensor tendons and flexor tendons inside the ostrich foot coordinate and cooperate to control the toe extension and toe flexion movements of different phalanges, so that the contact area and posture of the toes can be changed in time, reducing the The sinking of the foot maintains the stability of the body. In the late stage of touching the ground, the toes of the ostrich leave the ground, the compressed metatarsophalangeal joint recovers, and the stored elastic potential energy is converted into kinetic energy. Driven by the stretched flexor tendons, the phalanges will leave the ground in turn. Under the connection between the extensor tendons and the flexor tendons, the entire toe is in a circular arc shape, thereby improving the movement efficiency of the entire toe.

In order to imitate the function of the metatarsophalangeal joint and the movement posture of the ostrich foot when it touches the ground, the load-bearing rod 1, the guide rod 2, the first spring 3, the first slider 4, the second spring 6, the second slider 7, the third Parts such as the spring 8 and the first phalanx 10 have simulated the function of the ostrich metatarsophalangeal joint, which has played the role of storing and releasing energy. The first connecting rod 5 simulates the function of the long extensor/flexor tendon of the toe, and plays a role in connecting the third phalanx 16 and controlling the ground contact posture of the third phalanx 16 under the drive of the first slider 4 . The second connecting rod 9 simulates the function of the perforated penetrating stretch/flexor tendon, and plays the role of connecting the second phalanx 13 and controlling the posture of the second phalanx 13 under the drive of the second slider 7 .

The weight of an adult ostrich is 60-160kg, the continuous running speed is 50-60 km/h, and the area of the ostrich toes is 0.01m ² . Such a small toe area has to bear such a huge body weight, which requires the ostrich toe to have excellent cushioning and shock absorption performance, especially during high-speed running. The ostrich foot was dissected by the biological general anatomy technique, and the ostrich foot pad is composed of the toe cushion layer, fascia layer and skin layer in sequence from top to bottom, and the elastic modulus of these three layers increases in sequence.

In order to imitate the soft tissue material and assembly method of the ostrich foot pad, the toe pad layer of the foot pad unit, the fascia layer of the foot pad unit, and the skin layer of the foot pad unit were designed, and three kinds of silicone rubber with different hardness were used to simulate the elastic mold of the soft tissue of the ostrich foot pad. According to the measurement ratio, the foot pad unit is assembled sequentially from top to bottom according to the assembly sequence of the three layers of soft tissue of the ostrich foot, the toe pad, fascia and skin. According to the size of the first phalanx 10, the second phalanx 13 and the third phalanx 16, appropriate scaling is carried out, and the first foot pad unit 11, the second foot pad unit 14 and the third foot pad unit 17 are respectively designed to play a role Buffer vibration and improve stability.

The topography of the ostrich foot has a groove structure, which plays a role in reducing the sand entry resistance and sand fixation and limiting flow during the high-speed sand crossing of the ostrich, thereby improving the traction performance of the toes.

In order to imitate the groove structure of the ostrich toe, the middle ridge line of the ostrich toe is extracted, and according to the size of the first foot pad unit 11, the second foot pad unit 14 and the third foot pad unit 17, appropriate scaling is performed, The first sole 12, the second sole 15 and the third sole 18 are respectively designed to reduce sand entry resistance and improve traction.

The working principle of an adaptive posture-changing bionic mechanical foot:

When the bionic mechanical foot just touches the ground, the impact force from the ground is absorbed and dissipated by the first foot pad unit 11, the second foot pad unit 14 and the third foot pad unit 17, which realizes the function of buffering and vibration reduction, and improves the mechanical foot. ground contact stability, the weight of the whole body acts on the load-bearing rod 1, under the action of the guide rod 2, the load-bearing rod 1 moves downward to compress the first spring 3, and under the action of the first spring 3, the first slider 4 also moves downwards, and at the same time drives the first connecting rods 5 on both sides to move downwards. Under the action of the first connecting rods 5 on both sides, the third phalanx 16 on both sides contacts the ground. Force transmission, the second slider 7 will also move downwards, and drive the second connecting rod 9 on both sides to move downwards, the second phalanx 13 on both sides will also be in contact with the ground, and the third spring 8 will move on the second slider. 7 Under the action of downward movement, it will also be compressed, which imitates the movement of the metatarsophalangeal joints and the process of storing elastic potential energy when the ostrich foot just touches the ground. The contact area between the first phalanx 10 and the ground also reaches the maximum, and the first sole 12, the second sole 15 and the third sole 18 play the role of sand-fixing and current limiting, which improves the traction force of the whole mechanical foot.

Due to the characteristics of the spring itself that can be compressed and rebounded, when the bionic mechanical foot is in the middle of touching the ground or the robot is standing still, the non-directional movement of the center of gravity of the body will make the weight of the body pass through the load-bearing rod 1 on the first spring 3, the first Continuous transmission between the slider 4, the second spring 6, the second slider 7 and the third spring 8, the first spring 3, the second spring 6 and the third spring 8 will find a dynamic balance between compression and rebound At the same time, the first slider 4 and the second slider 7 will also float up and down under the action of the first spring 3, the second spring 6 and the third spring 8, respectively driving the first connecting rod 5 and the second connecting rod connected on both sides. The connecting rod 9 moves up and down, which makes the contact area between the third phalanx 16 and the second phalanx 13 on both sides and the first phalanx 10 in the middle change dynamically with the ground, so that the bionic mechanical foot can Self-adaptive real-time passive adjustments are made in the middle of touching the ground or when the robot is standing still, so as to achieve the purpose of anti-sinking.

When the bionic mechanical foot is in the late stage of touching the ground, the compressed first spring 3, second spring 6 and third spring 8 will return to their original state, and the first slider 4 and the second slider 7 will move upward under the action of the spring, Respectively drive the first connecting rod 5 and the second connecting rod 9 on both sides to move upward, and the third phalanx 16 and the second phalanx 13 on both sides will also move upward under the action of the first connecting rod 5 and the second connecting rod 9 respectively. Therefore, the third phalanx 16 and the second phalanx 13 on both sides and the first phalanx 10 in the middle are gradually arc-shaped, which imitates the movement posture of the ostrich when the toes are off the ground, and plays a role in improving exercise efficiency.

Claims (5)

1. A bionic mechanical foot with self-adaptive variable attitude, is characterized in that, comprises bearing bar, guide bar, the first slider link mechanism, the second slider link mechanism, the first toe mechanism, a pair of second toes The first toe mechanism and a pair of third toe mechanisms; the guide rod passes through the load-bearing rod, the first slider linkage mechanism and the second slider linkage mechanism in turn, and is threaded with the first toe mechanism; a pair of second toe The upper mechanism is respectively hinged on the left and right sides of the first toe mechanism; a pair of third toe mechanisms are respectively hinged on the outside of the second toe mechanism on the corresponding side; The three-toe mechanism is hinged; the two ends of the second slider linkage mechanism are respectively hinged with the second toe mechanism on the corresponding side; the guide rod section between the load-bearing rod and the first slider linkage mechanism is sleeved with The first spring; the second spring is sleeved on the guide bar section between the first slider linkage mechanism and the second slider linkage mechanism; the guide between the second slider linkage mechanism and the first toe mechanism A third spring is sleeved on the rod section. 2. A kind of self-adaptive attitude-changing bionic mechanical foot as claimed in claim 1, characterized in that, the first toe mechanism, the second toe mechanism, and the third toe mechanism are all composed of phalanges and foot pad units and the sole of the foot; the foot pad unit is pasted under the phalange, and the sole is pasted under the foot pad unit; the first toe mechanism, the second toe mechanism, and the third toe mechanism are hinged through the phalange; the second toe The second toe mechanism is hinged with the second slider link mechanism through its phalanges, and the third toe mechanism is hinged with the first slider link mechanism through its phalanges. 3. A kind of self-adaptive posture-changing bionic mechanical foot as claimed in claim 2, characterized in that, said foot pad unit consists of foot pad unit toe pad layer, foot pad unit fascia layer and foot pad successively from top to bottom The skin layer of the foot pad unit is composed of the toe pad layer of the foot pad unit, the fascia layer of the foot pad unit and the skin layer of the foot pad unit. 4. An adaptive posture-changing bionic mechanical foot as claimed in claim 2, wherein the sole of the foot is made of photosensitive resin material and processed by 3D printing technology. 5. A bionic mechanical foot with self-adaptive posture change as claimed in claim 1, wherein the first slider link mechanism comprises a first slider, two first connecting rods, and two first sliders. One end of the first connecting rod is respectively hinged, and the other ends of the two first connecting rods are respectively hinged with the outside of the third toe mechanism; the second slider linkage includes a second slider, two second connecting rods, and the second connecting rod Two ends of the two sliders are respectively hinged to a second connecting rod, and the other ends of the two second connecting rods are respectively hinged to the outside of the second toe mechanism.