JP2007007800A - Walking type robot, wheel type robot and absolute azimuth estimating method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To accurately obtain the absolute azimuth (absolute angle) required for controlling and correcting the moving locus of a robot without an expensive azimuth sensor in a walking type robot walking by repeatedly moving the free leg to the standing leg to ground. <P>SOLUTION: This walking type robot includes: an absolute position detector for detecting the absolute position of the grounding foot; an absolute position storage means for storing the absolute position of the grounding foot; and an absolute azimuth computing device for computing the absolute azimuth of the grounding foot. The absolute azimuth computing device estimates the absolute azimuth θ of the grounding foot of the (k-1)th step and/or the k-th step based upon the absolute position (x<SB>k</SB>, y<SB>k</SB>) of the grounding foot of the k-th step, the absolute position (x<SB>k-1</SB>, y<SB>k-1</SB>) of the grounding foot of the (k-1)th step, and the relative movement command value (Δx<SB>k</SB>, Δx<SB>k</SB>, Δθ<SB>k</SB>) of the grounding foot of the k-th step to the grounding foot of the (k-1)th step. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a mobile robot (for example, a walking robot, a wheel robot, etc.) that can freely move on a floor. Specifically, for estimating the absolute orientation of the mobile robot (for example, the angle in the global coordinate system (absolute coordinate system) that defines the coordinates of the space in which the mobile robot is active (hereinafter, the angle in the global coordinate system is called the absolute angle)) Regarding technology.

Mobile robots that can move freely on the floor, such as walking robots and wheel robots, have been developed. In this type of mobile robot, a movement trajectory is normally designated (teached) in advance by an operator, and the robot drives an actuator to move the designated trajectory. For example, in the case of a walking robot, the operator specifies the contact position of each foot in chronological order, and the robot moves the tip of each foot to the specified contact position. As a result, the robot moves on the designated locus.
If there is no bending in the robot's mechanical system, or if there is no slip between the robot (specifically, the sole of the robot or the robot wheel) and the floor, the robot moves along the specified trajectory. . However, in reality, the robot mechanical system is bent or a slip occurs between the robot and the floor, so that the actual movement locus of the robot may deviate from the movement locus designated by the operator.
For this reason, the actual position (absolute position) and / or the actual direction (absolute angle) of the robot is detected, and based on the deviation between the actual position and the taught position and / or the deviation between the actual direction and the taught direction, A control method has been developed in which a teaching position and / or teaching direction is corrected to move the robot on a movement locus designated. In order to effectively perform such a control method, it is important to accurately detect the absolute position and absolute azimuth (absolute angle) of the robot.

  Various methods have been developed for detecting the absolute position of the robot. For example, a method has been developed in which a camera is mounted on a robot, a marker whose position is known is photographed by the camera, and the camera position (that is, the position of the robot) is detected from the photographing result. Alternatively, a method for detecting the position of the robot by using radio waves or ultrasonic waves has been developed. For example, a method has been developed to detect the position of the receiver (ie, the position of the robot) by receiving radio waves flying into the robot's activity range and analyzing the received radio waves (oscillated from artificial satellites). Technology similar to GPS that receives radio waves and detects position). These techniques can be configured at a relatively low cost, and the detection accuracy is at a level that does not cause any practical problems.

On the other hand, as a method for detecting the absolute orientation of the robot, an orientation sensor (for example, a gyro sensor) is mounted on the robot, and the absolute orientation of the robot is detected from the output of the orientation sensor. For example, in the case of a walking robot, an orientation sensor is mounted on the body of the robot, and the absolute orientation of the body is detected by the orientation sensor. Then, the absolute azimuth of the toe (grounding foot) is calculated by adding the relative angle of the toe with respect to the torso to the detected absolute azimuth of the torso.
As apparent from the above description, in the conventional method for detecting the absolute direction of the robot, the detection accuracy is determined by the detection accuracy of the direction sensor. However, at present there is no low-priced azimuth sensor with high detection accuracy, and there has been a problem that an expensive azimuth sensor must be used to increase detection accuracy.
Japanese Patent Publication No. 7-4774

  The present invention has been made in view of the above situation, and its purpose is to use an expensive azimuth sensor for “absolute direction (absolute angle)” required for controlling and correcting the movement trajectory of the robot. It is to provide a technique that can be estimated with high accuracy.

A first robot of the present invention is a walking type robot that walks by repeatedly moving a free leg with respect to a standing leg and grounding, an absolute position detecting device that detects an absolute position of a grounded foot, and a detection Absolute position storage means for storing the absolute position of the grounded foot, the absolute position of the grounded foot of the kth step, the absolute position of the grounded foot of the (k-1) th step, and the (k-1) th step And (k-1) an absolute azimuth estimating device that estimates the absolute azimuth of the grounded foot at the (k-1) th step and / or the kth step using the relative movement command value of the grounded foot at the kth step with respect to the grounded foot.
In this robot, instead of using an azimuth sensor that detects the “absolute direction”, a detection device that detects the “absolute position” of the ground foot is used, and the “absolute position” of the ground foot detected by the detection device is used. To estimate the “absolute direction” of the grounding foot. As already described, the detection device that detects the absolute position of the grounding foot has higher detection accuracy than the azimuth sensor. Therefore, when the “absolute direction” of the grounding foot is estimated using the detected “absolute position” of the grounding foot, the estimated value substantially matches the “absolute direction” of the actual grounding foot. Therefore, when the movement trajectory of the robot is corrected using the estimated “absolute direction” of the grounding foot, the movement trajectory designated for the robot can be accurately moved.

The “k step” can be appropriately set according to the ground contact point at the time when the absolute direction is desired to be estimated. For example, the absolute azimuth of the current grounding foot (that is, the absolute azimuth of the foot of the standing leg (foot)) or the absolute azimuth of the grounding foot one step before (that is, the foot of the free leg (foot)) is grounded. If the user wants to estimate the absolute bearing of the toe at the time of contact, the “ground contact foot at step k” is set as the current contact foot, and the “ground contact foot at step (k−1)” is 1 from the current contact foot. It may be a grounded foot before walking.
In addition, the absolute position detection device may directly detect the absolute position of the robot's toes, or may detect the absolute position of the robot's head or torso and detect the detected head or It may be calculated by calculation based on the absolute position of the torso and the relative positional relationship of the toes with respect to the head or the torso (that is, the posture of the robot).

Here, the absolute position of the k-th grounded foot, the absolute position of the (k-1) -th grounded foot, and the relative movement command of the k-th grounded foot with respect to the (k-1) -th grounded foot It will be briefly described that the absolute azimuth of the ground foot of the (k-1) step and / or the k step can be estimated using the value.
FIG. 4 schematically shows the geometric relationship between the absolute position of the grounded foot at the (k−1) th step and the absolute position of the grounded foot at the kth step. In the figure, (x _k−1 , y _k−1 ) represents the absolute position of the grounded foot at the (k−1) th step, and (x _k , y _k ) represents the absolute position of the grounded foot at the kth step. ing. Further, the relative command value of the k-th ground contact foot with respect to the (k−1) -th ground contact foot is represented by (Δx _k , Δy _k , Δθ _k ). Further, Φ _k-1 represents the absolute angle of the (k-1) -th grounded foot with respect to the k-th grounded foot, and τ _k represents the k-th grounded foot with respect to the (k-1) -th grounded foot. Represents the relative position angle.
As is clear from the geometrical relationship shown in FIG. 4, the absolute azimuth θ _k-1 of the (k−1) th step is _obtained by adding the absolute angle Φ _k-1 and the relative position angle τ _k . The absolute azimuth θ _k of the k-th step is the relative angle command value of the ground contact foot of the k-th step with respect to the ground foot of the (k-1) -th step in the absolute direction θ _k-1 of the (k-1) -th step. It can be estimated that Δθ _k is added. Since the relative angle command value Δθ _k is known, if the absolute angle Φ _k-1 and the relative position angle τ _k can be calculated, the absolute azimuth θ _k-1 of the ground contact foot at the (k-1) th step The absolute azimuth θ _k of the _k-th ground contact foot can be estimated.
The absolute angle Φ _k−1 is calculated from the absolute position (x _k−1 , y _k−1 ) of the grounded foot at the (k−1) th step and the absolute position (x _k , y _k ) of the grounded foot at the kth step. Can be calculated. That is,
Φ _k−1 = atan2 (y _k −y _k−1 , x _k −x _k−1 )
It becomes.
On the other hand, since the relative movement command value (Δx _k , Δy _k ) is known, the relative position angle τ _k can be estimated using the relative movement command value (Δx _k , Δy _k ). That is,
τ _k = atan2 (Δy _k , Δx _k )
It becomes.
Therefore, the absolute position detection device detects the absolute position (x _k−1 , y _k−1 ) of the grounding foot at the (k−1) th step and the absolute position (x _k , y _k ) of the grounding foot at the kth step. if it is possible to estimate the (k-1) th step of the absolute azimuth theta _k-1 and k-th step of the absolute azimuth theta _k.

As is apparent from the above description, the absolute azimuth estimation device uses the absolute position of the k-th ground contact foot and the absolute position of the (k-1) -th ground contact foot to the k-th ground contact foot. Based on (k-1) means for calculating the absolute angle of the grounded foot at the step and (k-1) the relative movement command value of the grounded foot at the kth step with respect to the grounded foot at the (k-1) th step, (k-1) Means for estimating the relative position angle of the k-th ground contact foot with respect to the ground contact foot of the step, and means for estimating the absolute azimuth of the ground foot of the (k-1) step from the obtained absolute angle and relative position angle; Can be provided. Thereby, the absolute azimuth θ _k−1 of the contact foot at the (k−1) th step can be estimated.
Further, the absolute azimuth estimating device uses the estimated absolute azimuth of the ground foot of the (k−1) step and the relative angle command value of the ground foot of the k step with respect to the ground foot of the (k−1) step. Based on this, it is preferable to further include means for estimating the absolute bearing of the k-th ground contact foot. As a result, the absolute azimuth θ _k of the _k-th ground contact foot can be estimated.

The present invention also provides a novel method for calculating the absolute orientation of the grounding foot of a walking robot.
That is, the first absolute azimuth calculation method of the present invention is a method for estimating the absolute azimuth of the grounding foot of a walking robot that walks by repeatedly moving the free leg with respect to the standing leg and grounding, (K-1) a step of detecting the absolute position of the grounded foot in the step, a step of detecting the absolute position of the grounded foot in the kth step, and the absolute position of the detected grounded foot in the kth step (k− 1) a step of calculating an absolute angle of the grounded foot of the (k-1) step with respect to the grounded foot of the kth step using the absolute position of the grounded foot of the step; and (k-1) the grounding of the step. Based on the relative movement command value of the k-th grounded foot with respect to the foot, (k-1) a step of estimating the relative position angle of the k-th grounded foot with respect to the grounded foot of the step, and the obtained absolute angle and relative And a step of estimating the absolute azimuth of the contact foot at the (k−1) th step from the position angle.
According to this method, the absolute azimuth of the grounding foot of the walking robot can be accurately estimated without using an expensive azimuth sensor.

The second robot of the present invention relates to a wheel type robot that includes a vehicle body, a wheel that is rotatably attached to the vehicle body, and an actuator that drives the wheel, and that travels by rotating the wheel with the actuator. This wheel type robot includes an absolute position detection device that detects the absolute position of the vehicle body, and an absolute position history storage unit that sequentially stores the absolute position of the vehicle body detected by the absolute position detection device at predetermined time intervals or predetermined movement intervals. And an absolute azimuth estimating device that estimates the absolute azimuth of the vehicle body from the absolute position history stored in the absolute position history storage means.
In the wheel type robot, the direction does not change abruptly except when the robot turns on the spot, and its direction gradually changes as the robot travels on the floor surface. Therefore, by storing the history of the absolute position of the vehicle body, the travel locus of the vehicle body is known, and the absolute azimuth (orientation) of the vehicle body (wheel type robot) is estimated from the travel locus (that is, the tangential angle of the travel locus). can do. In the second robot of the present invention, the absolute position of the vehicle body is detected at a predetermined time interval or a predetermined movement interval, and the absolute azimuth of the vehicle body is estimated from the history of the absolute position of the detected vehicle body. Since the absolute position of the vehicle body can be detected with high accuracy, the absolute direction of the vehicle body can be accurately estimated without using an expensive direction sensor. If the robot's movement trajectory is controlled / corrected using the accurately estimated absolute azimuth of the vehicle body, the robot can be moved on the movement trajectory designated for the robot with high accuracy.

  The absolute azimuth estimation device described above can estimate the absolute azimuth of the vehicle body based on the absolute positions of the vehicle bodies at two points specified from the absolute position history stored in the absolute position history storage means. In this case, it is preferable that at least one of the absolute positions of the vehicle bodies at the two points is a moving average of the absolute positions of the vehicle bodies at a plurality of points stored in the absolute position history storage unit. By using a moving average of absolute positions at a plurality of points, it is possible to further improve the accuracy of estimation of the absolute direction.

The present invention also provides a novel method for estimating the absolute orientation of a wheeled robot. That is, the second absolute azimuth estimation method of the present invention includes a vehicle body, a wheel rotatably attached to the vehicle body, and an actuator that drives the wheel, and a wheel that travels by rotating the wheel with the actuator. A method for estimating the absolute orientation of a robot, the step of detecting the absolute position of the vehicle body at a predetermined time interval or predetermined movement interval, and the absolute position of the vehicle body at two points specified from the history of the detected absolute position Estimating the absolute azimuth of the vehicle body from the position.
According to this method, the absolute direction of the robot can be accurately estimated without using an expensive direction sensor.

A biped robot 10 according to an embodiment of the present invention will be described with reference to the drawings. First, the mechanical configuration of the biped robot 10 will be described with reference to FIG. As shown in FIG. 1, the biped robot 10 includes a left leg link 147, a waist 101, and a right leg link 117.
The left leg link 147 includes a left upper leg 148, a left knee joint 150, a left lower leg 152, a left ankle joint 158, and a left foot tip 162. The left knee joint 150 has a variable joint angle around the pitch axis y, and the left ankle joint 158 has a variable joint angle around the pitch axis y and a joint angle around the roll axis x. In FIG. 1, a joint is represented by an actuator that changes the joint angle for the sake of clarity of illustration. For example, reference numeral 150 is commonly used for actuators that change the joint angles of the knee joint. Reference numeral 154 is an actuator that changes the joint angle of the ankle joint 158 around the pitch axis y, and reference numeral 156 is an actuator that changes the joint angle of the ankle joint 158 around the roll axis x.
An absolute position detection device 160 that detects the absolute position of the left foot tip 162 is attached to the left foot tip 162. As the absolute position detection device 160, a device that detects an absolute position using radio waves or ultrasonic waves can be used. For example, it is possible to use a technology that detects the position of the receiver by receiving radio waves flying into the robot's activity range and analyzing the received radio waves (receiving radio waves oscillated from artificial satellites) The same technology as GPS that detects the position can be used). When using this technique, a receiver for receiving radio waves is attached to the left foot tip 162. Further, it is also possible to use a technique for detecting the position of the receiver by transmitting ultrasonic waves toward the range of activity of the robot and analyzing the reception timing of the ultrasonic waves received by the robot. Alternatively, the position can be detected using a radio wave radar or an ultrasonic radar.

  The left and right leg links 117 and 147 are symmetrical, and the right leg link 117 includes an upper right thigh 118, a right knee joint 120, a right lower thigh 122, a right ankle joint 128, and a right foot tip 132. The right knee joint 120 has a variable joint angle around the pitch axis y, and the right ankle joint 128 has a variable joint angle around the pitch axis y and a joint angle around the roll axis x. An absolute position detection device 130 is also attached to the right foot tip 132.

  The waist 101 includes a waist plate 108 and a waist pillar 104, and a waist joint 106 is provided between them. A head 102 is placed on the apex of the waist pillar 104. The inclination angle of the lumbar column 104 around the pitch axis y and the inclination angle around the roll axis x are not affected even when the hip joint 106 rotates.

  The left leg link 147 and the waist 101 are connected by a left hip joint 146. The left hip joint 146 includes an actuator 140 that changes the joint angle around the gravity line z-axis, an actuator 142 that changes the joint angle around the pitch axis y, and an actuator 144 that changes the joint angle around the roll axis x. . The right leg link 117 and the waist 101 are connected by a right hip joint 116. The right hip joint 116 includes an actuator 110 that changes the joint angle around the gravity line z-axis, an actuator 112 that changes the joint angle around the pitch axis y, and an actuator 114 that changes the joint angle around the roll axis x. .

When walking using the mechanical system described above, the relative postures of the left leg link 147, the waist 101, and the right leg link 117 must be changed so that the result of walking is obtained as a result. Therefore, in this embodiment, gait data that specifies the positions and postures of the left foot tip 162, the waist 101, and the right foot tip 132 is used. The gait data is data that designates the positions and postures of the left foot tip 162, the waist 101, and the right foot tip 132 in a global coordinate system (absolute coordinate system) that determines the coordinates of the space in which the biped robot 10 is active.
When the gait data is created, the gait data is given to the biped robot 10. The biped robot 10 adjusts the joint angle of each joint according to the gait data, and changes the positions of the left toe 162 and the right toe 132 over time. As a result, the relative posture of the left leg link 147 and the right leg link 117 changes with time, and the biped walking robot 10 walks.
Note that the absolute position when the left foot tip 162 and the right foot tip 132 are in contact with the floor (hereinafter simply referred to as the absolute position of the ground foot) is detected by the absolute position detectors 160 and 130, respectively. Further, the bearing foot orientation is calculated by an absolute orientation calculation device described below. The gait data is corrected so that the deviation between the absolute position of the contact foot detected by the absolute position detection devices 160 and 130 and the absolute position (teaching position) specified by the gait data becomes zero. Similarly, the gait data is corrected so that the deviation between the absolute azimuth of the contact foot calculated by the absolute azimuth calculating device and the absolute azimuth (teaching azimuth) specified by the gait data becomes zero. Thereby, the biped walking robot 10 can walk faithfully on the walking locus designated by the gait data.

  Next, an apparatus for calculating the absolute direction (the absolute angle of the grounded foot) when the toes 132 and 162 of the biped walking robot 10 are grounded will be described with reference to FIG. This absolute azimuth calculating device is mounted on the biped walking robot 10 and the absolute angle of the foot that is the stance of the biped robot 10 and the foot when the foot that is the free leg is in contact with the ground. Calculate the absolute angle of the plane. As shown in FIG. 2, the absolute azimuth calculation device includes the absolute position detection devices 160 and 130 described above, the foot position storage unit 12, the relative command value input unit 28, and the arithmetic unit 20.

The foot position storage unit 12 stores the absolute position of the grounded foot (the absolute position of the grounded foot (foot)). The foot position storage means 12 detects the absolute position of the left toe 162 detected by the absolute position detecting device 160 when the left toe 162 contacts the ground and the absolute position detecting device 130 when the right toe 132 contacts the ground. The absolute position of the right foot tip 132 is input. The foot position storage means 12 alternately stores the absolute position of the grounded foot input from the absolute position detecting device 130 and the absolute position of the grounded foot input from the absolute position detecting device 160 in time series.
In addition, the absolute azimuth calculation apparatus of the present embodiment has the absolute angle of the toe (foot) that is a standing leg and the toe (foot) when the toe that is a free leg is in contact with the ground. Calculate the absolute angle. For this reason, the absolute position stored in the foot position storage means 12 is only the absolute position of the grounding foot of the standing leg and the absolute position of the grounding foot of the free leg (grounding foot one step before).

The relative command value input means 26 inputs the relative command value of the current grounding foot (current stance) with respect to the grounding foot (current free leg) one step before to the arithmetic unit 20. The relative command value is calculated based on the gait data described above. That is, the gait data is data that designates the positions and postures of the left toe 162 and the right toe 132. Therefore, based on the gait data, it is possible to calculate a relative command value (Δx, Δy, Δθ) of the current grounding foot (standing leg) with respect to the grounding foot (current free leg) one step before.
As described above, the gait data has a deviation between the actual contact foot position and the teaching position of 0 and the deviation between the actual absolute angle of the contact foot and the teaching angle is 0 by the correction device. It is corrected so that For this reason, the relative command values (Δx, Δy, Δθ) input from the relative command value input means 26 are created based on the gait data corrected by the correction device.

The arithmetic unit 20 uses the absolute position of the grounded foot of the standing leg, the absolute position of the grounded foot of the free leg, and the relative command value of the grounded foot of the standing leg with respect to the grounded foot of the free leg stored in the foot position storage means 12. Based on this, the absolute angle (absolute direction) of the contact leg of the free leg and the standing leg is calculated. That is, in FIG. 4 already described, the (k-1) -step grounding foot is a free-grounding foot, and the k-th grounding foot is a standing-grounding foot. Accordingly, the arithmetic unit 20 calculates the absolute angle Φ _k−1 of the free-grounded foot with respect to the grounded foot of the standing leg, and calculates the relative position angle τ _k of the grounded foot of the standing foot with respect to the grounded foot of the leg. The absolute angle θ _k−1 of the contact leg of the free leg is calculated from the absolute angle Φ _k−1 and the relative position angle τ _k . Then, an absolute angle theta _k-1 of the ground leg of the free leg, based on the relative angle command value of the ground leg stance to ground the foot of the free leg, and calculates the absolute angle theta _k grounding leg stance. For this purpose, the computing device 20 includes an absolute angle calculating means 22, a relative position angle calculating means 24, a free leg foot absolute angle calculating means 26, and a standing foot absolute angle calculating means 30 (see FIG. 4).
The absolute angle calculation means 22 includes the absolute position (x _k , y _k ) of the grounded foot of the standing leg stored in the foot position storage means 12 and the absolute position (x _k−1 , y _k− ) of the grounded foot of the free leg. _{From 1} ), the absolute angle Φ _k−1 of the contact leg of the free leg with respect to the contact leg of the standing leg is calculated.
The relative position angle calculating unit 24 calculates the relative position angle τ _k of the grounded foot of the standing leg with respect to the grounded foot of the free leg using the relative command value (Δx _k , Δy _k ) input from the relative command value input unit 28. To do.
The free leg foot absolute angle calculating means 26 adds the absolute angle Φ _k−1 calculated by the absolute angle calculating means 22 and the relative position angle τ _k calculated by the relative position angle calculating means 24 to add the free leg foot absolute angle calculating means 26. The absolute angle θ _k−1 of the grounding foot is calculated.
The stance leg absolute angle calculation means 30 is a relative angle command of the ground contact leg of the stance leg with respect to the contact leg of the free leg to the absolute angle θ _k−1 of the contact leg of the free leg calculated by the absolute foot angle calculation means 26 of the leg. The value Δθ _k is added to calculate the absolute angle θ _k of the ground contact leg of the standing leg. The absolute angle θ _k of the grounding foot of the stance calculated by the stance foot absolute angle calculating means 30 is output to the correction device and used for correcting the gait data.

A procedure by which the absolute azimuth calculating apparatus described above calculates the absolute azimuth (absolute angle) of the grounded foot of the standing leg will be described with reference to FIGS. Note that the process of calculating the absolute azimuth (absolute angle) of the grounding foot of the standing leg is performed at a timing when one foot tip 162 or 132 touches the floor and the position of the foot tip 162 or 132 stops moving.
As shown in FIG. 3, the absolute azimuth calculation device first detects the absolute position (x _k , y _k ) of the grounding foot of the standing leg and uses the detected absolute position (x _k , y _k ) as the foot position. It memorize | stores in the memory | storage means 12 (S10). Next, the absolute position (x _k−1 , y _k−1 ) of the contact leg of the free leg (one step before) stored in the foot position storage means 12 is read (S12).
Next, based on the absolute position (x _k , y _k ) of the grounded foot of the stance detected in step S10 and the absolute position (x _k−1 , y _k−1 ) of the grounded foot of the free leg read in step S12, The absolute angle Φ _k−1 of the free-grounding foot with respect to the standing-grounded foot is calculated (S14). The calculation formula for calculating the absolute angle Φ _k-1 from the absolute position (x _k , y _k ) of the ground contact leg of the standing leg and the absolute position (x _k-1 , y _k-1 ) of the contact leg of the free leg has already been described. is doing.
Next, a relative command value ((Δx _k , Δy _k , Δθ _k ) of the grounded foot of the standing leg with respect to the grounded foot of the free leg is read (S 16). (Δx _k , Δy _k , Δθ _k ) are input.
When the relative command values (Δx _k , Δy _k , Δθ _k ) are input to the computing device 20, the computing device 20 determines the relative position of the grounded foot of the standing leg to the grounded foot of the free leg based on the relative command values Δx _k , Δy _k. The position angle τ _k is calculated (S18). The calculation formula for calculating the relative position angle τ _k based on the relative command values Δx _k and Δy _k has already been described.
In step S20, the arithmetic unit 20 adds the absolute angle Φ _k−1 calculated in step S14 and the relative position angle τ _k calculated in step S18 to add the absolute angle θ _k−1 of the contact leg of the free leg. Is calculated.
When the absolute angle θ _k−1 of the contact leg of the free leg is calculated, the calculated absolute angle θ _k−1 and the relative command value Δθ _k read in step S16 are added, and the absolute angle θ of the contact leg of the stance leg is calculated. _k is calculated (S22). Absolute angle theta _k grounding leg stance calculated is outputted to the correction device (S24). Correction apparatus performs processing for correcting the gait data using the absolute angle theta _k input.

As is apparent from the above description, the biped robot 10 is based on the absolute position of the grounded foot of the free leg, the absolute position of the grounded foot of the standing leg, and the relative command value of the grounded foot of the standing leg with respect to the grounded foot of the free leg. Then, the absolute angle (absolute direction) of the contact leg of the free leg and the contact leg of the standing leg is calculated. Since the absolute position of each foot tip can be detected with high accuracy, the absolute angle (absolute azimuth) of the grounding foot can be calculated (detected) with high accuracy without using an azimuth sensor.
In addition, since it is not necessary to use an azimuth sensor, it is possible to reduce costs, reduce the weight of the robot, solve the problem of arrangement space, reduce the load on the controller (CPU), reduce the power consumption, and the like.

In the biped walking robot 10 described above, the absolute position detection devices 130 and 160 are mounted on the respective toes 132 and 162, but the present invention is not limited to such a form. For example, an absolute position detection device is provided on the head or torso of a biped robot, the absolute position of the head or torso is detected by the detection device, and the absolute position is detected from the angle information of each joint of the robot. You may make it convert into the position of 162.
In addition to the above-described device, the apparatus for detecting the absolute position of the robot captures a known marker by the camera, and calculates the position of the grounding foot based on the position of the captured marker on the screen and the posture of the robot. You may do it.
In the embodiment described above, the azimuth sensor is not mounted on the biped walking robot 10, but the present invention is not limited to such a form. For example, an orientation sensor is mounted on a biped walking robot, and the absolute angle of the grounded foot is estimated using the absolute angle detected by the orientation sensor and the absolute angle calculated by the absolute angle calculation device of the present invention. You may do it.

Furthermore, in the above-described embodiment, the absolute angle of the contact leg of the stance (k step) is calculated, and the gait data is corrected using the calculated absolute angle of the contact leg of the stance. However, the present invention is not limited to such a form, and for example, the gait data may be corrected using the absolute angle of the contact leg of the free leg ((k-1) step). As is clear from the above description, the absolute angle of the contact foot at the (k-1) th step is calculated when the (k-1) th step is a stance, and the (k-1) th step. Calculated when the eye is a free leg. Therefore, the gait data may be corrected using the calculated average value of the two absolute angles. By using the average value of the absolute angles calculated twice, the accuracy of gait data correction can be improved.
An example of an absolute azimuth calculating apparatus when such a configuration is adopted is shown in FIG. As shown in FIG. 10, first, the absolute angle of the ground contact leg of the stance calculated by the calculation means 30 when the (k−1) step is a stance is stored in the storage means 34. In the next cycle (cycle in which the (k-1) step is a free leg), the calculation means 26 calculates the absolute angle of the contact leg of the free leg. The average value calculation means 36 calculates the average value of the absolute angle of the contact foot calculated by the calculation means 26 and the absolute angle of the contact foot stored in the storage means 30, and outputs the average value to the correction device. Thus, since the gait data is corrected using the absolute angle of the contact foot calculated twice, the correction accuracy can be improved.

(2nd Embodiment) The cart robot 40 which concerns on 2nd Embodiment of this invention is demonstrated with reference to drawings. First, the mechanical configuration of the cart robot 40 will be described. FIG. 5 shows the mechanical configuration of the cart robot 40.
As shown in FIG. 5, wheels 56 and 46 are disposed at the lower portion of the vehicle body 44. The rotating shafts 54 and 48 of both wheels 56 and 46 are arranged on the same axis, and the vehicle body 44 can tilt in a direction orthogonal to the axis. A motor 52 is connected to the right wheel 56, and a motor 50 is connected to the left wheel 46. When the motor 52 rotates, the right wheel 56 rotates, and when the motor 50 rotates, the left wheel 46 also rotates. The motors 50 and 52 are fixed to the lower surface of the vehicle body 44.
On the vehicle body 44, an absolute position detection device 42 for detecting the absolute position of the vehicle body 44 is attached. Various devices that can be used for the biped robot 10 of the first embodiment can be used as the absolute position detection device 42. That is, a device that detects an absolute position using radio waves or ultrasonic waves, or a device that detects an absolute position using a camera can be used.

In order for the cart robot 40 to travel (move) on the floor surface, the motor 52 rotates the right wheel 56 and the motor 50 rotates the left wheel 46. When the cart robot 40 travels straight, both wheels 46 and 56 are rotated in the same direction at the same rotational speed. On the other hand, when the bogie robot 40 is turned, it can be turned by changing the rotational speeds of the right wheel 56 and the left wheel 46. That is, when the rotational speed of the right wheel 56 is greater than the rotational speed of the left wheel 46, the vehicle body 44 turns to the left, and when the rotational speed of the left wheel 46 is greater than the rotational speed of the right wheel 56, the vehicle body 44 turns to the right. The direction of the vehicle body 44 of the carriage robot 40 changes due to the difference in rotational speed between the wheels 46 and 56, and the direction of the vehicle body 44 gradually changes as the carriage robot 40 moves.
Further, since the cart robot 40 is an inverted pendulum type cart, the vehicle body 44 has an inverted control for maintaining the inverted state, and the position and orientation (absolute angle) of the vehicle body 44 are set to the designated position and orientation. Both of the position controls to be controlled are performed. For the inverted control, various conventionally known control methods (inverted pendulum control, etc.) can be used. On the other hand, the position and orientation of the vehicle body 44 is controlled by driving the motors 50 and 52 according to the travel locus data given in advance with the travel locus data instructing the travel locus of the cart robot 40.
However, if a slip occurs between the wheels 46 and 56 and the floor surface, the traveling locus of the cart robot 40 deviates from the traveling locus designated in advance by the traveling locus data. Therefore, the travel locus data is corrected so that the deviation between the position of the vehicle body 44 detected by the absolute position detection device 42 and the position of the vehicle body 33 specified by the travel locus data (teaching position) becomes zero. The travel locus data is set such that the deviation between the absolute orientation (absolute angle) of the vehicle body 44 calculated by the absolute orientation calculation device described below and the absolute orientation (teaching orientation) of the vehicle body 33 specified by the travel locus data becomes zero. Is corrected. As a result, the cart robot 40 travels on the designated travel locus without deviating from the designated travel locus.

  The cart robot 40 can also turn on the spot by rotating the right wheel 56 and the left wheel 46 at different rotational directions at the same rotational speed. However, in the following description, the case where the cart robot 40 turns on the spot is not considered, and the description is limited to the case where the cart robot 40 turns while traveling forward on the floor surface.

Next, an apparatus for calculating the absolute azimuth (absolute angle) of the cart robot 40 (vehicle body 44) will be described with reference to FIG. As shown in FIG. 6, the absolute azimuth calculating device is composed of the absolute position detecting device 42, the absolute position history storing unit 62, and the absolute angle calculating unit 58 already described.
The absolute position history storage means 62 stores the absolute position of the cart robot 40 (vehicle body 44) detected by the absolute position detector 42 in chronological order at a predetermined time interval (Δt). That is, the absolute position history storage means 62 stores the actual travel locus of the cart robot 40 at a predetermined time interval (Δt).

The absolute angle calculation means 58 calculates the absolute azimuth (absolute angle) of the vehicle body 44 from the travel locus of the cart robot 40 (vehicle body 44) stored in the absolute position history storage means 62.
As already described, the cart robot 40 turns by the difference in rotational speed between the wheels 46 and 56, and the absolute angle of the cart robot 40 (vehicle body 44) gradually increases as the cart robot 40 travels (moves). To change. For this reason, the absolute angle at a certain point in time of the cart robot 40 is the same as the angle in the tangential direction of the traveling locus of the cart robot 40 at that point. Therefore, as shown in FIG. 8, the absolute position (x _k−1 , y _k−1 ) of the cart robot 40 at time t _k−1 is detected, and the absolute position at time t _k (= t _k−1 + Δt). If (x _k , y _k ) is detected and the time interval Δt is sufficiently small, the absolute angle θ _k-1 at time t _k−1 is set to atan2 (y _k −y _k−1 , x _k −x _k-1 ). The absolute angle calculation means 58 specifies the absolute position coordinates of two points of the vehicle body 44 from the absolute position history of the vehicle body 44 stored in the absolute position history storage means 62, and the absolute angle of the vehicle body is determined from the coordinates of the two points. θ is calculated.

A processing procedure in which the absolute azimuth calculating apparatus described above calculates the absolute azimuth (absolute angle) of the cart robot 40 will be described with reference to FIGS. Note that the process of calculating the absolute angle of the cart robot 40 (vehicle body 44) is performed every time the process of detecting the absolute position of the vehicle body 44 is performed.
As shown in FIG. 7, the absolute angle calculation device first detects the absolute position (x _k , y _k ) of the vehicle body 44 by the absolute position detection device 42 (S30), and detects the detected absolute position (x _k , y _k ) is stored in the absolute position history storage means 62 (S32).
Next, the coordinates of the absolute position (x _k−1 , y _k−1 ) of the vehicle body 44 stored in the absolute position history storage means 62 in the previous process are read (S34).
In step S36, the absolute position of the vehicle body 44 detected in step S30 (that is, the current position (x _k , y _k ) of the cart robot 40) and the absolute position of the vehicle body 44 read in step S34 (that is, from the current position). Based on the position (x _k−1 , y _k−1 ) of the cart robot 40 before Δt, the absolute angle θ _k−1 of the cart robot 40 before Δt is calculated. Specifically, the absolute angle θ _k−1 is _obtained by atan2 (y _k −y _k−1 , x _k −x _k−1 ) (see FIG. 8).
The absolute angle theta _k-1 at step S36 is calculated, and outputs the absolute angle theta _k-1 of the bogie robot 40 that the calculated correction device (S38). The correction device corrects the travel locus data based on the absolute angle θ _k−1 of the cart robot 40 input from the absolute bearing calculation device.

  As is clear from the above description, the cart robot 40 stores the absolute position of the vehicle body 44 at a predetermined time interval (Δt), and calculates the absolute angle of the cart robot 40 (vehicle body 44) from the stored travel locus. . Since the absolute position of the vehicle body 44 can be detected with high accuracy, the absolute angle of the cart robot 40 can be calculated with high accuracy.

The above description has been made on the assumption that the cart robot 40 does not turn at the same place. When the cart robot 40 may turn at the same place, it is determined whether or not the cart robot 40 is turning at the same location from the given travel locus data, and only when the cart robot 40 is not turning at the same location. What is necessary is just to calculate the absolute angle of the cart robot 40 using the said absolute direction calculation apparatus. On the other hand, when the cart robot 40 is turning at the same place, the absolute angle of the cart robot 40 can be detected by an orientation sensor (for example, a gyro sensor) separately mounted on the cart robot 40. Alternatively, without using an azimuth sensor (gyro sensor), the turning angle of the cart robot 40 can be calculated by integrating the encoder values of the left and right wheels, and the absolute angle of the cart robot 40 can be obtained from the turning angle. . Accordingly, it is possible to cope with a case where the period in which the cart robot 40 is turning at the same place is included.
When the above configuration is adopted, an azimuth sensor is mounted on the cart robot 40, but the absolute angle is detected by the azimuth sensor only during a period when the cart robot 40 is turning at the same place. Since the period for calculating the absolute angle by the azimuth sensor is limited, the absolute angle of the cart robot 40 can be accurately calculated without using an expensive azimuth sensor.

Further, in the above-described cart robot 40, the absolute position of the vehicle body 44 is detected at a predetermined time interval. However, the present invention is not limited to such a form. For example, the cart robot 40 moves a predetermined distance. The absolute position of the vehicle body 44 may be detected every time.
Further, the cart robot 40 described above has the absolute position (x _k , y _k ) of the vehicle body 44 detected in the current processing cycle and the absolute position (x _k−1 ) of the vehicle body 44 detected in the previous cycle. , Y _k-1 ), the absolute angle of the cart robot 40 (vehicle body 44) was calculated (see FIG. 8). However, as shown in FIG. 9, a moving average of a plurality of absolute positions detected by the absolute position detection device 42 can be used for the absolute positions of two points necessary for calculating the absolute angle. As a result, the absolute angle estimation accuracy can be improved.

The preferred embodiments of the present invention have been described in detail above. However, these are merely examples, and the present invention can be implemented in various modifications and improvements based on the knowledge of those skilled in the art. it can.
It should be noted that the technical elements described in this specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology illustrated in the present specification or the drawings achieves a plurality of objects at the same time, and has technical utility by achieving one of the objects.

The figure which shows the machine structure of the biped walking robot which concerns on this embodiment. The functional block diagram of the absolute direction calculation apparatus which calculates the absolute direction of the grounding leg of a biped walking robot. The flowchart which shows the process sequence of the absolute azimuth | direction calculation apparatus shown in FIG. (K-1) The figure which shows typically the geometric relationship of the absolute position of the ground-contact leg of the step and the absolute position of the ground-foot of the k step. The figure which shows the machine structure of a cart robot. The functional block diagram of the absolute direction calculation apparatus which calculates the absolute direction of a cart robot. The flowchart which shows the process sequence of the absolute direction calculation apparatus shown in FIG. The figure which shows typically the relationship between the absolute position of two places of a trolley robot, and the absolute azimuth | direction (absolute angle) of a trolley robot. The figure for demonstrating the other method of calculating the absolute azimuth | direction of a cart robot. The functional block diagram which concerns on the modification of the absolute direction calculation apparatus shown in FIG.

Explanation of symbols

10: Biped walking robot 12: Foot position storage means 20: Computing device 22: Absolute angle calculation means 24: Relative position angle calculation means 26: Swing leg absolute angle calculation means 28: Relative command value input means 30: Standing leg Foot absolute angle calculating means 40: cart robot 42: absolute position detector 44: vehicle body 46, 56: wheels 50, 52: motor

Claims (8)

It is a walking robot that walks by repeatedly moving the free leg with respect to the standing leg and grounding,
An absolute position detector for detecting the absolute position of the grounding foot;
Absolute position storage means for storing the absolute position of the detected grounding foot;
The absolute position of the k-th grounded foot, the absolute position of the (k-1) -th grounded foot, and the relative movement command value of the k-th grounded foot with respect to the (k-1) -th grounded foot. A walking robot comprising: (k-1) an absolute azimuth estimating device that estimates an absolute azimuth of a grounding foot at the (k-1) th step and / or the kth step. The absolute azimuth estimation device uses the absolute position of the ground foot of the kth step and the absolute position of the ground foot of the (k-1) th step, and touches the ground foot of the (k-1) th step with respect to the ground foot of the kth step. Means for calculating the absolute angle of the foot;
(K-1) The relative position angle of the k-th grounded foot with respect to the (k-1) -th grounded foot is estimated using the relative movement command value of the k-th grounded foot with respect to the grounded foot of the step. Means,
The walking robot according to claim 1, further comprising means for estimating an absolute azimuth of the contact foot at the (k−1) th step from the obtained absolute angle and relative position angle.   The absolute azimuth estimation device uses the estimated absolute azimuth of the ground foot of the (k-1) th step and the relative angle command value of the ground foot of the kth step with respect to the ground foot of the (k-1) step. The walking robot according to claim 2, further comprising means for estimating an absolute azimuth of the k-th ground contact foot. A method for estimating the absolute orientation of the grounding foot of a walking robot that walks by repeatedly moving the swinging leg with respect to the standing leg and grounding,
(K-1) detecting the absolute position of the ground contact foot at the step;
detecting the absolute position of the k-th ground contact foot;
Using the detected absolute position of the grounded foot at the kth step and the absolute position of the grounded foot at the (k-1) th step, the absolute position of the grounded foot at the (k-1) th step with respect to the grounded foot at the kth step Calculating a corner;
(K-1) The relative position angle of the k-th grounded foot with respect to the (k-1) -th grounded foot is estimated using the relative movement command value of the k-th grounded foot with respect to the grounded foot of the step. Process,
An absolute azimuth estimation method comprising: estimating an absolute azimuth of the contact foot at the (k-1) th step from the obtained absolute angle and relative position angle. A wheel-type robot that includes a vehicle body, a wheel that is rotatably attached to the vehicle body, and an actuator that drives the wheel, and that travels by rotating the wheel with the actuator,
An absolute position detection device for detecting the absolute position of the vehicle body;
Absolute position history storage means for sequentially storing the absolute position of the vehicle body detected by the absolute position detection device at predetermined time intervals or predetermined movement intervals;
A wheel type robot comprising: an absolute azimuth estimation device that estimates an absolute azimuth of a vehicle body from an absolute position history stored in an absolute position history storage unit.   6. The absolute azimuth estimating apparatus estimates the absolute azimuth of the vehicle body using the absolute positions of the two vehicle bodies identified from the absolute position history stored in the absolute position history storage means. The wheel type robot described in 1.   7. The wheeled robot according to claim 6, wherein at least one of the absolute positions of the vehicle bodies at the two points is a moving average of the absolute positions of the vehicle bodies at a plurality of points stored in the absolute position history storage means. . A method of estimating an absolute direction of a wheeled robot that includes a vehicle body, a wheel rotatably attached to the vehicle body, and an actuator that drives the wheel, and that travels by rotating the wheel with the actuator,
Detecting the absolute position of the vehicle body at a predetermined time interval or a predetermined movement interval;
An absolute azimuth calculation method comprising: estimating an absolute azimuth of a vehicle body from absolute positions of the vehicle body at two points specified from a history of detected absolute positions.

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