KR20050002302A - Real-time posture control for biped robot using inclination sensors - Google Patents

Abstract

PURPOSE: A posture controller of a biped robot at a real time and a method thereof are provided to control the posture of the biped robot through cheap components with a simple method at the real time. CONSTITUTION: A first and a second uniaxial inclination sensors detects inclination information according to the inclined status of a biped robot at a real time and offers to a control unit(S610). The control unit receives the outputs of the first and the second uniaxial inclination sensors and seize the inclined status of the ground to be located to the biped robot(S620). The control unit seizes joint control values corresponding to the inclined statuses of the ground from a storing unit(S630a,S630b,s630c). Then, the control unit offers the corresponding joint control value to a joint control unit. The joint control unit compensates the posture by controlling the corresponding joint according to the inputted joint control value(S640). Thereby, the posture of the biped robot is controlled at a real time with two cheap uniaxial inclination sensors.

Description

Real-time posture control for biped robot using inclination sensors}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to robot engineering, and in particular, the real-time posture of a biped robot using a uniaxial or biaxial tilt sensor that detects the tilt of the biped robot and the tilt of the biped robot. It relates to an apparatus and a method for controlling the.

Traditionally, robots have been used mainly in industrial sites for carrying heavy objects that are difficult for human beings, or for tasks requiring high precision. Over time, non-industrial robots such as pet robots, lifesaving robots, and human robots have emerged, in addition to industrial robots that perform only certain tasks in the industrial sector. In recent years, research on human robots that help humans have continued to evolve.

Compared to industrial robots, human robots have been developed to have similar shapes and degrees of freedom as humans. In particular, research on biped robots with two legs like humans is being actively conducted.

As a result of this research on biped robots, Japan's Honda has introduced a biped robot named P2 developed in December 1996. P3 has improved its capabilities and developed ASIMO, which is said to be the highest level of biped robots. Sony developed the SDR-4X in 1997 after developing an entertainment robot called SDR-3X.

In Korea, there are Lucy, the first bipedal robot developed by Dajin Systems, and Antroid TOy Robot, developed jointly by Mini Robot and Samsung Electronics.

These biped robots require a lot of skills because they have to move on their own, and in particular, they need to have considerable skills in posture control because they need to stand upright with both legs.

Most of the biped walking robots that are developed or published are performing posture control using a 3-axis gyro attitude sensor. However, the three-axis gyro attitude measuring sensor is quite expensive, and since the biped walking robot must control the posture based on the information on the three axes, there is a problem that requires the processing.

Therefore, there is a need for an additional method that enables the biped walking robot to be controlled in a simple manner while using a low-cost product.

The present invention has been made to solve the above-described problems, and an object of the present invention is to enable a real-time control of a posture of a biped walking robot by a simple method through a low cost component.

1 is a simplified configuration diagram of a biped walking robot to which a real-time posture control method of a biped walking robot according to an embodiment of the present invention is applied.

2 is a view showing a tilted state of the biped walking robot.

3 is a view showing that the posture correction by controlling the joints of the left and right legs in the front and rear tilted state.

4 is a view showing that the posture correction by controlling the joint of the leg of the left and right legs in the left and right tilted state.

5 is a block diagram of a real-time posture control device of a biped robot according to an embodiment of the present invention.

6 is a flowchart illustrating the operation of the real-time attitude control apparatus of the biped robot according to an embodiment of the present invention.

According to an aspect of the present invention, there is provided an upper body, a waist having two waist joints connected to a lower side of the upper body, and two connected to each of the two waist joints and having an ankle joint and a knee joint. A real-time posture control device of a biped robot configured to include a leg, the apparatus comprising: a first uniaxial tilt sensor arranged to detect a degree of inclination with respect to one axis and to detect a front and rear inclination of the biped robot; A second one-axis tilt sensor configured to detect an inclination degree with respect to one axis and to detect left and right tilts of the biped robot; A storage unit storing angle adjustment values of the corresponding joints to be corrected in posture according to the front and rear slopes and the left and right slopes as a mapping table; A joint controller for selectively operating the joint according to the input value; And grasping the inclination state and inclination of the biped walking robot by the outputs of the first and second uniaxial inclination sensors, and determining the angle adjustment value of the corresponding joint to compensate for the inclination by providing the determined inclination to the storage unit. And a control unit controlling the joint adjusting unit by the determined angle adjusting value.

On the other hand, the present invention according to another feature for achieving the above technical problem is the upper body, the waist having two waist joints connected to the lower side of the upper body, is connected to each of the two waist joints and having ankle joint and knee joint In the real-time posture control method of a biped robot comprising two legs, the first uniaxial tilt sensor for detecting the front and rear inclination and the second uniaxial tilt sensor for detecting the left and right inclination are disposed in the biped walking robot, and At least a first or second uniaxial tilt sensor which stores angle adjustment values of the waist joint, the ankle joint, and the knee joint corresponding to the inclination angle with respect to the inclination and the inclination angle with respect to the left and right as a mapping table and is input in real time. Map the output of the map to the mapping table to find the angle adjustment value of the corrected joint Adjust the clause.

The uniaxial tilt sensor includes a magnetic, a gyro (angular velocity), an acceleration, a mercury sensor, and the like.

With reference to the accompanying drawings, a real-time posture control device and method of a biped robot according to the features of the present invention will be described in more detail.

1 is a simplified configuration diagram of a biped walking robot to which a real-time attitude control method of a biped walking robot using a uniaxial tilt sensor according to an embodiment of the present invention is applied.

As shown in FIG. 1, the biped walking robot 100 is designed and manufactured in a structure similar to a human being as much as possible based on the human body structure. The head 10 and the upper body 20 connected to the upper part of the upper body 20 are illustrated. Left arm 30 connected to the left side of the right, the right arm 40 connected to the right side of the upper body 20, the waist 50 connected to the lower portion of the upper body 20, and the left leg 60 connected to the waist 50, respectively It consists of the right leg 70.

Here, the left and right arms 30 and 40 have two joints, and the waist 50 has the first waist joint 51 and the second waist joint 52 corresponding to each leg 60 and 70. The left leg 60 has a left knee joint 61 and a left ankle joint 62, and the right leg 70 has a right knee joint 71 and a right ankle joint 72.

In particular, the first and second lumbar joints (51, 52) has a degree of freedom to lift the legs back and forth, as well as to open the legs or bow down. Here, three degrees of freedom refers to degrees of freedom for front, rear, left and right, and up and down, and the coordinate axes correspond to x, y, and z axes as an example. The left and right knee joints 61 and 71 have 1 degree of freedom, and the left and right knee joints 62 and 72 have 2 degrees of freedom.

On the other hand, the first and second lumbar joints (51, 52), left and right neck joints (62, 72) and the joint of the arm connected to the upper body 20, the motor for moving the mechanical skeleton connected to the corresponding degrees of freedom ( Not shown).

Joints used in the posture control of the present invention are the joints of the waist 50 and the leg 60, and in the case of the first and second lumbar joints 51 and 52, the degrees of freedom corresponding to the z-axis among three degrees of freedom are postures. Do not use for control. z Degrees of freedom are degrees of freedom that allow you to raise and lower the legs.

The degree of freedom and arrangement of the biped walking robot to which the present invention configured as described above is applied is the structure of the simplest and most stable biped walking robot according to the freedom of positioning of the biped walking robot verified through many existing studies. It is the same structure as P2 mentioned by Honda.

On the other hand, the biped walking robot 100 of the present invention is a configuration for achieving the present invention, the first uniaxial tilt sensor (Tilt sensor) 80 and the second uniaxial tilt 90 is disposed on the upper body 20 do. The arrangement position is a principle that is arranged to sense the left and right inclination degree and the front and rear inclination degree of the upper body 20, according to this principle is usually disposed at any point on the central axis of the upper body 20, precise It is preferable to mount on the lower side of the upper body 20 as much as possible for the measurement.

The first and second uniaxial tilt sensors 80 and 90 are sensors that detect tilt with respect to one axis, that is, the horizontal axis. As shown in FIG. 1, the first uniaxial inclination sensor 80 detects the front and rear inclination degree, and the second uniaxial inclination sensor 90 detects the left and right inclination degree. That is, the first uniaxial tilt sensor 80 detects an inclination (an angle α between the reference plane and the inclined plane) generated when the biped walking robot 100 is in a forward and backward tilted state as shown in FIG. 2, the second uniaxial tilt sensor 90 has an inclination (an angle between the left and right legs 60 and 70) generated when the biped walking robot 100 is in a left and right tilted state as shown in (b) of FIG. 2. beta)).

When the tilting state of the biped walking robot 100 is generated in the front, rear, left, and right directions, the first and second uniaxial tilt sensors 80 and 90 detect respective corresponding tilt angles. In FIG. 2, the dotted line has no inclination.

2, it can be seen that the biped walking robot 100 of the present invention has two basic tilt states.

Hereinafter, the attitude control method of the present invention according to each inclined state will be described with reference to FIGS. 3 and 4.

3 is a view showing that the posture correction by controlling the joints of the left and right legs in the front and rear tilted state.

In FIG. 3, (a) is a side view showing a normal posture of the biped walking robot 100 based on one leg, and the biped walking robot 100 is on a flat surface. (B) is a side view showing the posture correction by controlling the ankle joints (62, 72) when the biped walking robot (100) is located on the ground inclined back and forth, and on all the areas above the ankle joints (62, 72) When the position change occurs and the movement of the upper body 20 is seen, the moving distance is very large.

(C) is a side view showing the posture correction by controlling the knee joints 61 and 71 when the biped walking robot 100 is located on the ground inclined back and forth, and on all parts of the knee joints 61 and 71. When the position change occurs and the movement of the upper body 20 is observed, the movement distance is smaller than in the case of (a).

(D) is a side view showing the posture correction using the hip joints 51 and 52 when the biped walking robot 100 is located on the ground inclined forward and backward, and only the portion above the waist joints 51 and 52 is positioned. The change occurs and the movement of the upper body 20 is very small.

Therefore, the posture control of the biped walking robot 200 in the tilting state before and after is most effective to control and correct the back joints (51, 52).

At this time, when controlling the lumbar joints 51 and 52, the two lumbar joints 51 and 52 should always be kept horizontal, and the controlling lumbar joint control value (that is, the adjusting angle) is proportional to the inclined plane. In more detail, the waist joint adjustment value is adjusted to be equal to the angle of the inclined surface as shown in Equation 1 below.

remind Is the hip joint control value at the time of late reflex, and θ (t) is the angle of inclination of the ground with respect to time.

Hereinafter, the attitude control method according to the left and right tilted states will be described with reference to FIG. 4. 4 is a view showing that the posture correction by controlling the joint of the leg of the left and right legs in the left and right tilted state.

In Figure 4, (a) is a front view of the biped walking robot 100 on the lower body part (waist, leg) on a flat surface, there is no inclination angle between the left and right legs (60, 70).

(B) is a front view showing the state of the lower body when the biped walking robot 100 is located on the ground inclined left and right, the inclination of the ground is low left and high right. Therefore, the left leg 60 is in the same state as in the case of (A) shown by a dotted line, but the right leg 70 should be bent for posture correction. At this time, the degree of bending the right leg 70 becomes more severe as the slope of the ground is severe, the exact value of the length of the right leg 70 on the flat (that is, the length to the ankle joint and lumbar joint) to H At this time, the bending should be made such that H- _{ate ×} tanθ. Is the inclination angle of the ground.

In order to tilt the right leg 70 to the corresponding value as described above, the angle of the right neck joint 72, the right knee joint 71, and the second waist joint 52 must be adjusted.

When the correction angle of each joint to be corrected in the left and right tilted state is represented by Equation 2 to Equation 4 below.

θ _k = π-θ _a -θ _h

In the above equation, θ _h is a hip joint adjustment value at the time of inclination, θ _a is an ankle joint adjustment value, θ _k is a knee joint adjustment value. Θ _a , θ _h , and θ _k are angles as shown in FIG. 4. H is the length of the leg, l _ate is the distance between the two legs, l _sh is the length between the ankle and knee joint, and l _th is the length between the waist and knee joint.

As described above, the present invention detects the inclination angle of the ground through the first and second uniaxial inclination sensors (80, 90), and accordingly the respective positions of the joints using the equations (1) to (4) The posture correction can be performed by calculating the adjustment value to be obtained for the correction.

However, the present invention uses a mapping table to solve this problem, because the problem of causing a loss in the sensor information processing speed occurs when calculating the adjustment value of each joint whenever the slope of the ground changes as described above.

The mapping table is a table in which an adjustment value of each joint calculated by Equations 1 to 4 is already matched to a set value according to the slope of the ground (left and right tilt and front and rear tilt). For example, if the inclination of the ground is 10 degrees left and right and 30 degrees back and forth, the adjustment value of each joint is stored as a matching value.

Hereinafter, a real-time attitude control apparatus and attitude control operation of a biped walking robot using a uniaxial tilt sensor will be described with reference to FIGS. 5 and 6.

5 is a block diagram of a real-time posture control device of a biped robot according to an embodiment of the present invention. 6 is a flowchart illustrating the operation of the real-time attitude control apparatus of the biped robot according to an embodiment of the present invention.

As shown in FIG. 5, the real-time posture control device of the biped walking robot of the present invention includes first and second uniaxial tilt sensors 80 and 90, a control unit 200, a storage unit 300, and a joint control unit ( 400).

The first and second uniaxial tilt sensors 80 and 90 detect the tilt information according to the tilted state of the biped walking robot 100 in real time and provide the tilt information to the controller 200 (S610).

Then, the controller 200 receives the outputs of the first and second uniaxial tilt sensors 80 and 90 to determine the inclination state of the ground on which the biped robot 100 is currently located (S620). The inclination state grasped above is a forward and backward inclination (A), a left and right inclination (B), or both cases, a compound inclination (C) and a degree of inclination (ie, inclination angle) of the ground.

When the controller 200 detects the inclination state of the ground as described above, the controller 200 reads the corresponding joint adjustment value corresponding to the determined inclination state (A, B, C) from the storage unit 300 (S630a, S630b). , S630c). The storage unit 300 stores the above-described mapping table.

Then, the controller 200 provides the corresponding joint adjustment value to the joint controller 400, and the joint controller 400 adjusts the joint according to the joint control value input from the controller 200. Correction (S640).

Here, if the inclination information is detected only in the first uniaxial inclination sensor 80, the joint controller 400 will adjust only the first and second lumbar joints 51 and 52 by the inclination angle of the ground. The joint adjustment values of the first and second lumbar joints 51 and 52 which are adjusted when the front and rear slopes A are in effect affect the degree of freedom to adjust the direction of lifting and lowering the upper body from three degrees of freedom.

On the other hand, if the inclination information is detected only in the second uniaxial tilt sensor 90, the joint control unit 400 corresponds to the first and second lumbar joints (51, 52), the knee joint of the leg, the ankle joint of the leg Adjust according to the joint control value. Here, the joint adjustment value for adjusting the first and second lumbar joints 51 and 52 when the left and right tilts B is a degree of freedom for moving the lower body in a state where the upper body is fixed at three degrees of freedom is the front and rear slopes ( A) This is different from the joint control value.

In the case of the compound tilt C, both the joint adjustment values of the front and rear tilt A and the left and right tilt B are used.

In the above, the present invention by installing a mean filter at the input terminal of the control unit 200 to remove the noise of the signal input from the first and second uniaxial tilt sensor (80, 90), thereby improving the reliability of the operation It can increase.

On the other hand, the above-described embodiment of the present invention has been described using the example of detecting the left and right and the front and rear tilt using two uniaxial tilt sensors.

However, at the level of those skilled in the art, two uniaxial tilt sensors can be easily replaced by one biaxial tilt sensor. At this time, it is preferable that one biaxial tilt sensor can detect the same effect as the two uniaxial tilt sensors, that is, the front, rear, and left and right tilts.

The technical spirit of the present invention has been described above with reference to the accompanying drawings, but this is by way of example only and not intended to limit the present invention. In addition, it is obvious that any person skilled in the art can make various modifications and imitations without departing from the scope of the technical idea of the present invention.

The present invention can be easily obtained on the market, and it is effective to implement real-time attitude control of the biped walking robot using two inexpensive single-axis tilt sensors.

In addition, the present invention can grasp the posture state of the biped walking robot as a simple operation of processing only the output of the 1-axis tilt sensor, and the overall processing speed is fast and real-time application by finding and correcting the corrected value from the table. It has an easy effect.

Claims (8)

In the real-time posture control device of a biped walking robot comprising an upper body, a waist having two waist joints connected to the lower side of the upper body, and two legs connected to each of the two waist joints and having an ankle joint and a knee joint , A tilt sensor unit for detecting front, rear, left and right tilts of the biped walking robot; A storage unit which stores a corresponding joint to be posture corrected and the angle adjustment value of the corresponding joint matched to the front and rear and left and right tilts detected by the tilt sensor unit as a mapping table; A joint controller for selectively operating the joint according to the input value; And Determine the inclination state and the inclination of the biped walking robot by the output of the inclination sensor unit, determine the angle adjustment value of the joint to compensate for the inclination by providing the determined inclination to the storage unit, and the determined angle adjustment value Real-time posture control device of a biped robot comprising a control unit for controlling the joint control. In a real-time posture control method of a biped walking robot comprising an upper body, a waist having two waist joints connected to the lower side of the upper body, and two legs connected to each of the two waist joints and having an ankle joint and a knee joint , An inclination sensor unit for detecting the front and rear and left and right tilts of the biped walking robot is installed in the biped walking robot, and the waist joint, the ankle joint, respectively matched to the inclination angle matched to the front and rear inclination and the inclination angle to the left and right tilt. A real-time posture control method of a biped robot, characterized in that for performing a real-time posture correction using a mapping table recording the angle adjustment value of the knee joint. The method according to claim 1, The tilt sensor unit is a real-time attitude control device of the biped robot, characterized in that disposed on the central axis of the upper body. The method according to claim 3, The tilt sensor unit, A first uniaxial tilt sensor which detects an inclination degree with respect to one axis and is arranged to detect a forward and backward inclination of the biped walking robot; A real-time posture control device of a biped robot, comprising: a second uniaxial tilt sensor configured to detect an inclination of one axis and detect a left and right tilt of the biped robot. The method according to claim 3, The tilt sensor unit, Real-time posture control device of a biped robot, characterized in that the biaxial tilt sensor for detecting the front and rear and left and right tilt of the biped robot. The method according to claim 4, The mapping table is The hip joint angle adjustment value for moving the upper body of the biped walking robot back and forth with respect to the front and rear tilt information is matched, and the upper body of the biped robot is fixed with respect to the left and right tilt information to move up and down to the landing surface. Real-time posture control device of the biped walking robot, characterized in that the angle adjustment value of the waist joint, the knee joint, the ankle joint is matched. The method according to claim 6, The waist joint angle adjustment value for the front and rear tilt is a real-time posture control device of a biped robot, characterized in that the same value as the inclination angle according to the front and rear tilt of the state. The method according to claim 7, The bipedal walking robot, wherein the hip joint angle adjustment value θ _h , the knee joint angle adjustment value θ _k , and the ankle joint angle adjustment value θ _a for the left and right tilts are calculated by the following equation. Real-time attitude control device. θ _k = π-θ _a -θ _h Where H is the length of the leg, l _ate is the distance between the two legs, l _sh is the length between the ankle and knee joint, and l _th is the length between the lumbar and knee joint.