JPH0631668A - Output correcting device of tilt sensor for leg type moving robot - Google Patents

Abstract

PURPOSE:To improve drift correction accuracy of a tilt sensor by obtaining an interference angle obtained by assuming no action by compliance, and obtaining estimated floor reaction force from the interference angle so as to correct a sensor output in accordance with a difference from actual floor reac tion force, in an angle between a floor surface supposed by target walk capacity and the actual floor surface. CONSTITUTION:An estimated tilt of a virtual plane including an tread estimated location is obtained by kinematic calculation from a robot attitude tilt estimated value and an articulated displacement detection value, and an estimated interference angle is obtained from a supposed floor surface tilt. Next from this estimated interference angle, estimated floor reaction force moment about a reference action point is obtained, based on a compliance model. Actual reaction force moment about the same action point to a 6-axis force sensor detection value is obtained. Then from a difference between the estimated floor reaction force moment and actual floor reaction force moment, a correction value is calculated from a correction rule, to correct a tilt sensor output.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for correcting output of a tilt sensor for a legged mobile robot, and more specifically, it estimates a posture of a robot by estimating a relative posture of the robot with respect to a known floor surface. Is estimated and the drift of the tilt sensor is corrected.

[0002]

2. Description of the Related Art Mobile robots, particularly legged mobile robots, are disclosed in JP-A-62-97005 and JP-A-63-15.
Those described in Japanese Patent No. 0176 are known. For details on robots including legged mobile robots, refer to "Robot Engineering Handbook" (edited by the Robotics Society of Japan, October 20, 1990).

[0003]

By the way, a legged mobile robot is usually provided with an inclination sensor for performing posture control. The tilt sensor estimates the tilt angle by integrating the output of the tilt angular velocity detector,
A device that detects the direction of gravity or a combination of these is used. However, there is a problem that the deviation of the estimated value diverges due to the drift of the detector in the one that integrates the output of the inclination angular velocity detector, and the deviation does not diverge in the gravity direction detection type, but the temperature drift occurs. Or the error of the detected value fluctuates under the influence of the inertial force due to the acceleration / deceleration motion of the robot. The combination type is
Compensating for these drawbacks, the detected value does not diverge, and the influence of inertial force due to the acceleration / deceleration motion of the robot can be significantly reduced, but the influence of temperature drift of the gravity direction detector is No improvement at all compared to the detection type alone.

Therefore, an object of the present invention is to eliminate the above-mentioned drawbacks, to estimate the attitude and inclination of the robot by estimating the relative attitude of the robot with respect to the floor surface on a known floor surface, and to estimate the tilt sensor drift described above. It is an object of the present invention to provide an output correction device of a tilt sensor for a legged mobile robot, which is capable of accurately correcting the above.

[0005]

In order to solve the above problems, the present invention provides a tilt for a link type legged mobile robot having a body and a plurality of legs as set forth in claim 1, for example. A sensor output correction device, wherein the robot is modeled by a rigid link, and a first means for setting a desired gait for walking on the assumed floor surface assuming a floor surface to be walked, Second means for detecting a posture inclination when the robot actually walks, and obtains and obtains a posture of the robot from at least the detected posture inclination on the assumption that there is no behavior or deformation due to compliance given to the robot. The third means for obtaining the relative positional relationship between the posture and the assumed floor surface, the leg contacting the assumed floor surface according to the compliance given to the robot from the obtained relative positional relationship. Fourth means for estimating a floor reaction force and / or moment that would otherwise occur according to preset characteristics, fifth means for determining the actual floor reaction force and / or moment of the robot, and the estimated floor reaction Force and / or moment and actual floor reaction force and /
Alternatively, a sixth means for obtaining the deviation of the moment and correcting the posture inclination detection value based on the obtained deviation is provided.

[0006]

[Action]

Paying attention to the fact that the relative posture inclination of the robot with respect to the actual floor can be quantified from the joint displacement of the robot and the actual floor reaction force, and using that concept, the absolute posture of the robot when walking on a known floor Since the normal posture is estimated and then the detection value of the tilt sensor is corrected, even if the tilt sensor drifts, it can be corrected well.

[0008]

Embodiments of the present invention will be described below by taking a bipedal legged mobile robot as an example of a mobile robot. FIG. 1 is an explanatory skeleton diagram showing the robot 1 as a whole, and each of the left and right leg links 2 has six joints (each joint is shown by an electric motor for driving it for the sake of convenience). . The six joints are in order from the top, joints 10R and 10L for rotating the legs of the waist (around the z axis) (R on the right side, L on the left side, the same applies below), roll direction of the waist (around the x axis). Joints 12R and 12L, joints 14R and 14L in the same pitch direction (around the y axis), joints 16R and 16L in the pitch direction of the knee, and joint 1 in the pitch direction of the ankle
8R, 18L and joints 20R, 20L in the same roll direction. Foots 22R, 22L are attached to the lower part of the joint, and the upper body (housing 24) is provided at the uppermost position, and the inside thereof The control unit 26 is stored in.

In the above, the hip joint is joint 10R (L),
12R (L) and 14R (L), and the ankle joint is composed of joints 18R (L) and 20R (L).
Further, the thigh links 32R, 32 are provided between the hip joint and the knee joint.
L, the lower leg links 34R, 34 between the knee joint and the ankle joint
Connected by L. Here, the leg link 2 is given six degrees of freedom for each of the left and right feet, and by driving these 6 × 2 = 12 joints (axes) to appropriate angles during walking, It is configured so that a desired movement can be given to the robot and the robot can walk arbitrarily in a three-dimensional space. As described above, the above-mentioned joint is composed of an electric motor, and further includes a speed reducer that boosts the output of the electric motor. For details, see yet another application proposed by the applicant (Japanese Patent Application No. 1-324218, JP-A-3-184782
No.) and the like, which are not the gist of the present invention per se, and further description will be omitted.

In the robot 1 shown in FIG. 1, a well-known 6-axis force sensor 36 is provided at the ankle portion, and force components Fx, F in the x, y, z directions are transmitted to the robot via the foot.
y, Fz and moment components Mx, M around that direction
By measuring y and Mz, the presence or absence of landing of the foot and the magnitude and direction of the force applied to the supporting leg are detected. Also foot 22R
In the four corners of (L), a capacitance type grounding switch 38 (see FIG.
(Not shown in the figure) is provided to detect whether or not the foot is grounded. Further, an inclination sensor 40 is installed on the upper body 24, and x
The tilt angle and tilt angular velocity with respect to the z axis in the −z plane and the yz plane, that is, with respect to the gravity (vertical) direction are detected. The electric motor of each joint is provided with a rotary encoder that detects the amount of rotation. Further, although omitted in FIG. 1, the inclination sensor 40 is provided at an appropriate position of the robot 1.
An origin switch 42 for compensating the output of No. 1 and a limit switch 44 for fail countermeasure are provided. These outputs are sent to the control unit 26 in the body 24 described above.

FIG. 2 is a block diagram showing the details of the control unit 26, which is composed of a microcomputer. The output of the tilt sensor 40 or the like is converted into a digital value by the A / D converter 50, and the output is converted to the bus 52.
Is sent to the RAM 54 via. The output of the encoder arranged adjacent to each electric motor is input into the RAM 54 via the counter 56, and the ground switch 3
Outputs of 8 and the like pass through the waveform shaping circuit 58 and are similarly transferred to the RAM 5
4 is stored. The control unit is provided with first and second arithmetic units 60 and 62 each composed of a CPU, and the first arithmetic unit 60 corrects the drift of the tilt sensor 40 as described later and determines the target joint angle. Calculate and RAM54
Send to. In addition, the second arithmetic unit 62 reads out the target value and the detected actual value from the RAM 54, calculates the control value necessary for driving each joint, and the each joint via the D / A converter 66 and the servo amplifier. To an electric motor that drives the.

Next, the operation of this control device will be described.
Since the gist of the present invention is to correct the drift of the tilt sensor, the following description will focus on that point.

FIG. 3 is a block diagram showing the operation,
FIG. 4 is a flow chart showing the operation.

In summary, in this control, the posture of the robot is estimated from the output of the tilt sensor and the joint displacement, and it occurs when the robot comes into contact with the floor surface assumed by the desired gait (hereinafter, referred to as "assumed floor surface"). In addition to finding the floor reaction force, the actual floor reaction force is compared and the tilt sensor output is corrected according to the deviation. That is, assuming that the assumed floor surface is known and there is essentially no shape deviation from the actual floor surface, the floor reaction force is at least estimated when the floor reaction force is estimated using the detection value of the tilt sensor. If it does not match the force, it is determined that the tilt sensor output itself, which is the basis of the estimation, was not correct, and the sensor output is corrected.

More specifically, a posture inclination estimated value (sensor output) is added to a posture inclination estimated deviation (described later) to obtain a posture inclination estimated value of the robot, and the behavior or deformation due to compliance is given to the robot from the obtained attitude inclination estimated value. The ground contact part of the posture required assuming that it is not (usually the foot 22R
A virtual plane (hereinafter referred to as “virtual plane”) including all or part of (L) is obtained, and an angle formed by the virtual plane and the assumed floor surface (hereinafter referred to as “interference angle”). Figure 5
Shows it. ) Is estimated. Then, by correcting the posture inclination estimation deviation so that the floor reaction force estimated from the interference angle matches the actual floor reaction force, a more accurate posture inclination estimated value is obtained and the sensor output is corrected. . This attitude inclination estimation deviation is the sensor output correction value. In this specification, "tilt" or "tilt" is used to mean a tilt angle.

From that intention, between the posture (virtual plane) and the assumed floor surface (or the actual floor surface) which are obtained assuming that the robot does not behave due to compliance based on the posture inclination and joint displacement of the robot described above. A model that represents the relationship between the interference angle and the floor reaction force when the posture (virtual plane) is deformed so as to contact the assumed floor surface (or actual floor surface) by the behavior due to compliance (hereinafter referred to as "compliance model"). Call). The structure of the model is specifically simplified as follows.

1. The interference angle is used to input the model. 2. The floor reaction force, which is the output of the model, is generally expressed by the force and moment acting on a certain action point. However, if the reference action point is set at or near the desired ZMP of the desired gait, the floor reaction force Even if the force component changes, the posture inclination of the robot hardly changes, so the force component of the floor reaction force may be ignored. Therefore, in the compliance model in this embodiment, only the moment component of the floor reaction force around the reference action point is calculated.

In the following, referring to the flow chart of FIG. 4, in S10, the virtual plane including the planned ground contact portion is calculated through kinematics calculation from the robot posture inclination estimated value (described later; initial value is sensor output) and the joint displacement detection value. That is, the actually measured posture of the robot is obtained based on the detected joint displacement value and the estimated posture inclination value of the robot, and the planned contact portion (foot 22R (L) in the absolute coordinate system in which the vertical direction coincides with one of the coordinate axes). The above-mentioned virtual plane including all or a part of) is obtained, and the estimated interference angle is obtained by taking the difference between the obtained virtual plane and the assumed floor surface. Then S
From step 12, the estimated floor reaction force moment around the reference action point (for example, the target ZMP) is obtained from the estimated interference angle obtained based on the compliance model.

This will be described with reference to FIGS. 6 to 8. In FIG. 6, the applicant of the present invention first discloses (Japanese Patent Application No. 4-137,
FIG. 881) is a side view of a robot provided with a mechanical compliance mechanism 100 on the ankle as proposed in No. 881). Assuming that there is no behavior due to compliance, a virtual plane is obtained from the ground contact portion of the supporting leg as shown in the figure, and an interference angle with the actual floor surface is obtained as shown in the figure. Then, when the compliance mechanism 100 operates, as shown in FIG. 7, the compliance mechanism 100 bends (deforms) by an interference angle,
A floor reaction force moment is generated. This means that the interference angle can be estimated by measuring the floor reaction force moment as shown in FIG. The present invention was made by paying attention to such knowledge, and a virtual plane and a floor surface (an assumed floor surface and an actual floor surface) including a portion that will be grounded when there is no behavior due to compliance It was established from the fact that the shape deviation was expressed by the concept of interference angle and that it could be estimated quantitatively from the floor reaction force moment. Therefore, the characteristics shown in FIG. 8 are prepared in advance through an experiment, and in S12, the floor reaction force moment is estimated from the estimated interference angle according to the characteristics.

The word "compliance" means ISO /
As defined in TR 8373: 1988 "The flexible behavior of a robot or its associated tools with respect to external forces (The flexible
behavior of a robot or any associated tools in re
"Compliance" means "sponse to external forces", and is based on the mechanism shown in Fig. 6 (Fig. 7) proposed by the applicant in Japanese Patent Application No. 4-137,881 previously mentioned above. And those by the control proposed in Japanese Patent Application No. 4-137,884, etc. However, this specification is not limited to this, and "compliance" includes the illustrated robot links 32, 34R (L) and the like. It is used in the sense of including the deformation (deflection) of
The term "compliance" used in this specification has a broader meaning than usual. In the first embodiment, the estimated inclination of the virtual plane is obtained by using the joint displacement detection value. Therefore, the “compliance” here means that the mechanism or the link is deformed as shown in FIG. 6 (FIG. 7). means.

Then, in S14, the actual floor reaction force moment around the same point of action is obtained from the value detected by the 6-axis force sensor 36. Subsequently, the process proceeds to S16, in which the difference between the actual floor reaction force moment and the estimated floor reaction force moment is the estimated value of the deviation between the actual posture inclination and the posture inclination detection value (output of the inclination sensor 40) according to the illustrated correction rule. The estimated tilt deviation is obtained (corrected if there is a previous value), and then added to the detected posture tilt value to obtain the estimated posture tilt value. The correction rule may be a low-pass filter type, but it is desirable to include pure integration in order to reduce a steady estimation error. In the case of the embodiment, the transfer function of the correction law is K / S (where K is an integration constant).

Subsequently, in S18 and subsequent steps, the posture of the desired gait is corrected so as to generate the desired floor reaction force while canceling the influence of the difference between the estimated posture inclination of the robot and the desired posture inclination.

That is, first, in S18, the interference angle in the ideal state is obtained from the desired floor reaction force moment by the inverse compliance model. This inverse compliance model is as shown in FIG. 3, and has the characteristic that the transfer function is opposite to that of the previous compliance model. That is, in this embodiment, since it is premised that the robot is provided with the compliance characteristic proposed in the previous application, in order to generate the floor reaction force expected in the desired gait, the behavior or the link deformation due to the compliance is calculated. It is necessary to add in advance. Therefore, the anti-compliance model as shown is set to obtain the interference angle in the ideal state.

Next, in S20, the interference angle command is determined by subtracting the difference between the estimated posture tilt and the target posture tilt from the obtained interference angle in the ideal state. This is because the moment that the upper body is tilted causes a moment, which is canceled. Next, in S22, the corrected posture in which the interference angle of the desired gait with respect to the assumed floor surface is corrected to the interference angle command is obtained, and in S24, the joint displacement of the actual robot is tracked using the joint displacement of the corrected posture as the joint displacement command. Let

The estimated posture inclination value obtained in S16 is used in S10 in the next loop of the flow chart of FIG. 4 to obtain the estimated interference angle.
At 16, the posture inclination estimated deviation is corrected in a form of correcting the previous value, and the posture inclination estimated value is corrected again by using the corrected posture inclination estimated deviation. In this way, by repeating the correction while assuming one side as the other side, the posture inclination estimated value converges to the true posture inclination. In the first loop of the flow chart of FIG. 4, the posture inclination estimation deviation is set to an appropriate initial value, for example, zero.

Although the posture is corrected in S18 to S22, this is not directly related to the correction of the posture inclination detection value and is for making the actual floor reaction force equal to the target floor reaction force. Therefore, it has no direct relationship with the gist of the present invention.

Since this embodiment is constructed as described above, even if the tilt sensor 40 drifts on a known floor surface, it can be corrected well. The floor surface of a structure such as a building has a fine response, but the average slope in a wide range is almost horizontal, and thus it is particularly suitable for such a place.

FIG. 9 is a block diagram showing a second embodiment of the present invention, and FIG. 10 is a flow chart showing its operation. As shown in the figure, the second embodiment differs from the first embodiment in that the estimated interference angle input to the model is used as the interference angle command (S100 in the flow chart of FIG. 10). Since the interference angle command is used instead of the joint angle displacement detection value to obtain the estimated interference angle in the second embodiment, “compliance” in the second embodiment is due to deformation of the mechanism or link and control. And both are included. The rest of the configuration and effects are the same as in the first embodiment.

FIG. 11 is a block diagram showing a third embodiment of the present invention, and FIG. 12 is a flow chart showing its operation. In the third embodiment, as shown in the figure, the estimated inclination of the virtual plane is calculated from the estimated posture inclination value of the robot and the weighted average (value) of the joint displacement detection value and the joint displacement command (value) to obtain the estimated floor surface. The point where the interference angle is estimated by taking the difference (Fig. 1
This is different from the first embodiment in S200) of the 2-flow chart. Assuming that the weight displacement coefficient of the joint displacement detection value of a certain joint is W (S), that of the joint displacement command (value) is (1-
W (S)) at this time, considering the contribution to the compliance operation, the joint with a large contribution has a larger weight of the joint displacement detection value, and the joint with a smaller contribution has a smaller weight. The joint displacement command value can be used almost as it is, and the calculation amount in kinematics calculation can be reduced. Besides that, the frequency of the behavior of the joint displacement may be taken into consideration. Since the joint displacement detection value contains high-frequency noise, it is better to give W (S) a low-pass filter characteristic. As shown in the figure, the third embodiment mixes the configurations of the first and second embodiments, so that the "compliance" here is due to a part of the control and the deformation of the mechanism or the link. Including and The remaining structure and effects are the same as those of the first embodiment.

FIG. 13 is a block diagram showing a fourth embodiment of the present invention, and FIG. 14 is a flow chart showing its operation. As shown in the figure, the feature of the fourth embodiment is that, contrary to the previous embodiments, the attitude inclination estimation deviation is obtained by obtaining the interference angle from the floor reaction force moment. That is, the anti-compliance model shown in FIG. 3 or the like is connected to the next stage of the 6-axis force sensor and its processing calculator, and the posture of the robot is obtained from the detected floor reaction force moment to determine the interference angle (first It will be estimated. On the other hand, from the difference between the estimated inclination of the virtual plane including the planned contact area and the estimated floor inclination, the estimated interference angle (second) is obtained as before, and the posture inclination estimated deviation is calculated according to the deviation of the estimated interference angles. I asked for it.
More specifically, in order to compare the second estimated interference angle with the first estimated interference angle in the same dimension, in the configuration of FIG. 3, an inverse compliance model is connected to the next stage of the compliance model. However, at that time, the product of the transfer functions of both models becomes 1, and as a result, the two cancel each other.

Due to the difference in the configuration described above, in the flow chart of FIG. 14, S302 to S306 are different from the flow chart of FIG. 3 of the first embodiment.
The remaining structure is the same as that of the first embodiment. Further, although an example in which the sensor output is corrected by using the interference angle instead of the floor reaction force moment is shown only when the first embodiment is modified, the present invention is not limited to this and the disclosure is omitted. It goes without saying that it is possible by modifying the embodiment or the third embodiment.

In the constructions of the above-mentioned first to fourth embodiments, in the one-leg supporting period, when the joint displacement command is obtained from the interference angle command and the desired gait, only the joint displacement command of the supporting leg ankle is given. You can fix it. In that case, the inverse kinematics calculation is not required, and the calculation amount is greatly reduced.

In the above construction, the floor shape is estimated by comparing the estimated value and the detected value with respect to the floor reaction force moment. Generally, the floor reaction force is represented by a force, a moment, and an action point, or a ZMP, a force acting on the ZMP, and a moment in the floor normal direction. In any of the expressions, not all the components are related to the posture control, so only the necessary elements need be obtained. The model can output only what is needed. When the floor reaction force is expressed using the desired ZMP of the desired gait as the reference point of action, the force component has almost no relation to the behavior of the posture inclination, and thus may be omitted. The output of the model may be the amount of deviation between the ZMP position of the floor reaction force of the model and the target ZMP. The reference point of action is a part of the robot, such as the ankle (ankle 18,
It may be at the intersection of 20R (L). That is, if the ankle moment is used instead of the floor reaction force moment in the embodiment, control of the ankle moment is realized.

Further, in the above construction, "inclination" and "inclination" mean the inclination angle, but the inclination angular velocity or a value obtained by linearly combining both may be used instead of the inclination angle.

Further, in the one-leg supporting period, the limit at which the floor reaction force moment can be generated is determined by the size of the foot contact surface and the vertical floor reaction force, and the non-linearity as shown in the compliance model shown in FIG. It has characteristics. The inverse compliance characteristic is naturally also non-linear, and when the target floor reaction force increases, the output interference angle increases rapidly. Since it is not desirable that the interference angle of the real robot becomes too large,
It is better to provide an interference angle limiter in the inverse compliance model so that the interference angle does not increase even if the target floor reaction force becomes too large. Alternatively, the characteristics of the inverse compliance model may be linearized to prevent the interference angle from rapidly increasing.

Further, since the compliance characteristic changes depending on the walking cycle such as the one-leg supporting period or the two-leg supporting period, when the compliance model in the above configuration is also changed depending on the walking period, the estimation accuracy of the posture inclination estimated value is high. Become.

Further, the compliance model shown in the above-mentioned configuration gives only the spring characteristic and does not consider the damping characteristic. However, for the robot having the damper characteristic, the model considering the damping characteristic is set. May be.

In estimating the posture inclination estimation deviation,
The estimated deviation should not change even if the floor reaction force changes after the estimated deviation converges by the correction rule.However, if the compliance model differs from the compliance of the actual robot, the estimated deviation changes when the floor reaction force changes. The correction of erroneously operates and the estimated deviation also fluctuates. Since the correction law is composed of integral and low-pass filter elements, if an attitude stabilization control is performed using the attitude inclination estimated value, a delay may occur due to this malfunction, and oscillation may occur in the worst case. . In order to prevent this, adaptive control that matches the compliance model with the identification value may be performed while identifying the compliance of the actual robot. In the adaptive control, normally, the fluctuation of the estimated floor reaction force output from the compliance model when the actual floor reaction force fluctuates is observed, and the fluctuation amount is identified so as to match the fluctuation amount of the real robot.

Further, although the bipedal legged mobile robot has been described above as an example, the present invention is not limited to this, and the present invention is also applicable to a legged mobile robot having three or more legs. However, it is applicable to other types of mobile robots such as wheel type and crawler type.

[0040]

According to the first aspect of the present invention, there is provided a device for correcting the output of an inclination sensor for a legged mobile robot of a link type having a body and a plurality of legs, wherein the robot is a rigid link. A first means for modeling and setting a desired gait for walking on the assumed floor surface assuming a floor surface to be walked, a first means for detecting a posture inclination when the robot actually walks 2 means, at least from the detected posture inclination,
Third means for obtaining the posture of the robot assuming that there is no behavior or deformation due to the compliance given to the robot, and for obtaining a relative positional relationship between the obtained posture and the assumed floor surface. From the positional relationship, a floor reaction force and / or a moment that would occur if the leg contacts the assumed floor surface due to the compliance given to the robot is estimated according to a preset characteristic.
Means, fifth means for obtaining an actual floor reaction force and / or moment of the robot, and deviation between the estimated floor reaction force and / or moment and the actual floor reaction force and / or moment, and the obtained deviation Since the sixth means for correcting the posture inclination is provided based on the above, even if the inclination sensor drifts, it can be accurately corrected.

According to a second aspect of the present invention, there is provided an output correction device of a tilt sensor for a link type legged mobile robot comprising a body and a plurality of legs, wherein the robot is modeled by a rigid link. , A first means for setting a desired gait for walking on the assumed floor surface assuming a floor surface to be walked,
Second means for detecting a posture inclination when the robot actually walks, at least a posture of the robot is obtained from the detected posture inclination, and a first relative positional relationship between the obtained posture and the assumed floor surface. A third means for determining the actual floor reaction force and / or moment of the robot, a fourth means for determining the actual floor reaction force and / or moment of the robot, and a third means for determining the posture of the robot and the assumed floor surface from the determined actual floor reaction force and / or moment. Fifth relative relative position relationship is obtained according to preset characteristics
And the sixth means for calculating the deviation between the first and second relative positional relationships and correcting the posture inclination detection value based on the calculated deviation. Even if a drift occurs, it can be accurately corrected.

In the third aspect of the present invention, the third means is configured to obtain the posture from the detected posture inclination and the joint displacement detection value of the robot link. Even if a drift occurs, it can be corrected well.

According to a fourth aspect of the present invention, the third means is configured to obtain the posture from the detected posture inclination and the joint displacement command value of the link of the robot, so that the configuration is simple. However, even if the tilt sensor drifts, it can be corrected well.

According to a fifth aspect of the present invention, the third means determines the posture based on the detected posture inclination and a weighted average value of the joint displacement detection value of the robot link and the joint displacement command value. Therefore, it is possible to use, for example, the command value of the joint having a low contribution to the compliance operation as it is, and it is possible to reduce the amount of calculation and achieve the above-mentioned effects.

[Brief description of drawings]

FIG. 1 is an explanatory diagram generally showing an output correction device of a tilt sensor for a mobile robot according to the present invention.

2 is a block diagram showing details of a control unit in FIG. 1. FIG.

FIG. 3 is a block diagram showing a first embodiment of the present invention.

FIG. 4 is a flow chart showing the operation of the first embodiment.

5 is an explanatory diagram showing interference angles shown in FIGS. 3 and 4. FIG.

FIG. 6 is an explanatory diagram showing the operation of the mechanical compliance mechanism previously proposed by the applicant in association with the interference angle.

FIG. 7 is an explanatory diagram showing a state in which the mechanism shown in FIG. 6 is bent by an interference angle.

FIG. 8 is an explanatory diagram showing the relationship between the floor reaction force moment and the interference angle, which is the basis of the present invention, obtained from FIGS. 6 and 7.

FIG. 9 is a block diagram showing a second embodiment of the present invention.

FIG. 10 is a flow chart showing the operation of the second embodiment.

FIG. 11 is a block diagram showing a third embodiment of the present invention.

FIG. 12 is a flow chart showing the operation of the third embodiment.

FIG. 13 is a block diagram showing a fourth embodiment of the present invention.

FIG. 14 is a flow chart showing the operation of the fourth embodiment.

[Explanation of symbols]

1 leg type mobile robot (bipedal walking robot) 2 leg link 10R, 10L joint for leg rotation 12R, 12L joint for roll direction of waist 14R, 14L joint for pitch direction of waist 16R, 16L pitch direction for knee Joints 18R, 18L Ankle pitch joints 20R, 20L Ankle roll joints 22R, 22L Foot 24 Upper body 26 Control unit 36 6-axis force sensor 100 Mechanical compliance mechanism

Claims (5)

[Claims] 1. An output correction device for a link-type legged mobile robot tilt sensor comprising a body and a plurality of legs, comprising: a. First means for modeling the robot with a rigid link and setting a desired gait for walking on the assumed floor surface assuming a floor surface to be walked, b. Second means for detecting a posture inclination when the robot actually walks; c. At least from the detected posture inclination, the posture of the robot is obtained on the assumption that there is no behavior or deformation due to the compliance given to the robot, and a relative positional relationship between the obtained posture and the assumed floor surface is obtained. Means, d. Based on the obtained relative positional relationship, a floor reaction force and / or a moment that would occur if the leg contacts the assumed floor surface due to the compliance given to the robot is estimated according to a preset characteristic. Means, e. Fifth means for determining the actual floor reaction force and / or moment of the robot, and f. A sixth means for obtaining a deviation between the estimated floor reaction force and / or moment and the actual floor reaction force and / or moment, and correcting the posture inclination detection value based on the obtained deviation. Output correction device for tilt sensor for legged mobile robot. 2. An output correction device of a tilt sensor for a link type legged mobile robot, which comprises an upper body and a plurality of legs, comprising: a. First means for modeling the robot with a rigid link and setting a desired gait for walking on the assumed floor surface assuming a floor surface to be walked, b. Second means for detecting a posture inclination when the robot actually walks; c. Third means for obtaining a posture of the robot from at least the detected posture inclination and obtaining a first relative positional relationship between the obtained posture and the assumed floor surface, d. Fourth means for determining the actual floor reaction force and / or moment of the robot, e. Fifth means for obtaining a second relative positional relationship between the posture of the robot and the assumed floor surface according to preset characteristics from the obtained actual floor reaction force and / or moment, and f. The deviation between the first and second relative positional relationships is calculated,
An output correction device for a tilt sensor for a legged mobile robot, comprising: a sixth means for correcting the posture inclination detection value based on the obtained deviation. 3. The legged movement according to claim 1, wherein the third means obtains the posture from the detected posture inclination and a joint displacement detection value of the link of the robot. Output correction device for robot tilt sensor. 4. The legged movement according to claim 1, wherein the third means obtains the posture from the detected posture inclination and a joint displacement command value of the link of the robot. Output correction device for robot tilt sensor. 5. The third means calculates the posture from the detected posture inclination and a weighted average value of joint displacement detection values of the robot links and joint displacement command values. An output correction device for a tilt sensor for a legged mobile robot according to item 1 or 2.