JP2009184034A - Legged robot and control method thereof - Google Patents

Abstract

A legged robot that can stably walk while driving a toe joint against disturbance, and a control method thereof.
A legged robot according to the present invention includes a torso 10 and a foot part 26 including a toe part 26a and a heel part 26b connected via a toe joint 27, and gait data is stored in the toe part. 26a includes the target position / posture 26a and the target angle of the toe joint 27, and the control unit 30 corrects the toe part correction amount for correcting the target position / posture of the toe part 26a based on the detection result of the distance detection unit 16, and the toe joint. Gait data is corrected based on the toe correction amount calculation unit for calculating the toe joint correction amount for correcting the target angle of 27, and the toe part correction amount and the toe joint correction amount calculated by the toe correction amount calculation unit And a toe correction amount calculation unit holds the toe joint correction amount at a predetermined value while the heel part 26b is getting out of bed.
[Selection] Figure 4

Description

  The present invention relates to a legged robot and a control method thereof.

  In recent years, in a robot having a foot portion at the lower end of the leg portion, a legged robot that walks while driving the toe joint, where the foot portion is composed of a toe and a heel connecting via a toe joint. Has been developed.

  In such a legged robot, firstly, the sole part of the foot part is brought into contact with the floor surface to be a supporting leg, and then the entire leg part (the entire robot) is lifted by pressing the floor surface on the back surface of the foot. The following walking motion is performed by driving the leg. The driven leg portion is a free leg, while the other leg portion is a support leg. Thus, a walking motion can be performed by alternately switching the free leg and the support leg. Here, in the bed leaving operation when switching from the supporting leg to the free leg, first, the heel is lifted, and the toe joint is driven to perform the kicking operation of the leg while standing on the toe. On the other hand, in the landing operation when switching from the free leg to the supporting leg, the entire foot sole of the foot is landed on the road surface by first landing from the heel and controlling the toe to follow the road surface. .

  Patent Document 1 discloses a foot tip device including two foot portions connected so as to be relatively swingable, and an actuator for relatively swinging these foot portions. According to the foot toe device described in Patent Document 1, the ground contact surface of the foot corresponding to the toe portion extends to both the front and rear of the swing shaft in a grounded state, and has a toe joint. The robot can be supported stably.

Patent Document 2 discloses a legged mobile robot that includes a foot portion provided at a lower end portion of a leg portion and a toe portion provided at a front end portion of the foot portion so as to be vertically rotatable. According to the legged mobile robot described in Patent Document 2, there is further provided an urging means for urging the toe portion so that the bottom surface of the toe portion is in the same direction as the bottom surface of the foot portion. Can walk.
JP 2005-169544 A Japanese Patent No. 3900959

  However, in the techniques described in Patent Documents 1 and 2, when trying to walk at high speed while driving the toe joint, there is a technique for stabilizing the robot against disturbance generated by contact with road surface unevenness or a person. Was not mentioned. Further, in the technique described in the application by the present applicant (Japanese Patent Application No. 2007-02863), the above technique discloses a technique for stably walking against Iran. However, the control amount of the robot may be discontinuous. is there. Here, if an attempt is made to ensure the continuity of the controlled variable by using a low-pass filter or the like unnecessarily, a phase delay may occur, and it may become unstable against disturbance. For example, when the trunk of the robot is tilted due to disturbance, the robot may fall without being able to obtain the floor reaction force moment necessary for returning the tilt from the foot. As described above, in the conventional technique, the technique of walking while driving the toe joint cannot be compatible with the technique of stabilizing against disturbance, and the problem of being unable to walk stably while driving the toe is problematic. was there.

  The present invention has been made to solve such a problem, and provides a legged robot capable of stably walking while driving a toe joint against disturbance, and a control method thereof. Objective.

  The legged robot according to the present invention detects a distance between a torso, a leg connected to the torso, a foot provided at a lower end of the leg, and a sole and a road surface of the foot. A leg-type robot comprising: a distance detecting unit that controls driving of the joint of the leg based on gait data; and the foot part is connected to the toe part via the toe part and the toe joint. The gait data includes a target position / posture of the toe part and a target angle of the toe joint, and the control unit includes a detection result of the distance detection unit. Based on the toe part correction amount for correcting the toe part correction amount for correcting the target position and orientation of the toe part and the toe joint correction amount for correcting the target angle of the toe joint, and the toe correction amount calculator The gait data is corrected based on the calculated toe part correction amount and toe joint correction amount. Comprising a Rufuyo data correcting portion, the toe correction amount calculating section, while the heel portion is off the floor and is intended for holding the toe joint correction amount to a predetermined value.

  In this way, the toe part correction amount and the toe joint correction amount are calculated independently, and while the buttocks are getting out of bed, the toe joint correction amount is held at a predetermined value to drive the toe joint, Even when the part leaves the floor and stands on the toe by the toe part, the continuity of the toe joint correction amount can be ensured. For this reason, it is not necessary to ensure the continuity of the controlled variable using a useless low-pass filter or the like, and the occurrence of phase delay can be suppressed. Therefore, the moment necessary for stabilization can be obtained well from the foot against disturbance, and the toe joint can be driven while walking stably.

  Further, the toe correction amount calculation unit may hold the toe joint correction amount at a predetermined value when a target angle of the toe joint is equal to or greater than a predetermined threshold. Thus, according to the target angle of the toe joint, it can be switched to hold the toe joint correction amount only by recognizing the driving of the toe joint by determining whether or not the buttocks are getting out of bed, Can respond well.

  Furthermore, the toe correction amount calculation unit calculates the toe joint correction amount in the immediately preceding control cycle among the toe joint correction amounts before the time when the buttocks get out of bed while the buttocks get out of bed. You may make it hold | maintain as a correction amount. Thus, while the buttocks are getting out of bed, the continuity of the toe joint correction amounts can be easily ensured by holding the toe joint correction amounts in the control cycle immediately before the buttocks get out of bed.

  Further, a toe coordinate system for controlling the foot part is defined on the toe part relative to the ground surface, and the toe correction amount calculation unit is based on the detection result of the distance detection unit. The deviation between the target position and orientation of the toe part in the toe coordinate system and the actual position and orientation is calculated, the toe part correction amount is calculated by multiplying the deviation by a predetermined gain, the target angle of the toe joint and the actual angle A deviation from the angle may be calculated, and the toe joint correction amount may be calculated by multiplying the deviation by a predetermined gain. In this way, by defining the toe coordinate system for the toe part and calculating the toe part correction amount and the toe joint correction amount separately in the toe coordinate system, the correction amount calculation is performed while the buttocks are getting out of bed. Can be executed easily.

  Furthermore, a body posture detection unit that detects the posture of the body is further provided, and the control unit calculates a deviation between a target posture of the body and an actual posture based on a detection result of the body posture detection unit. The gait data correction unit may calculate and correct the gait data so as to reduce the deviation.

  In addition, a center-of-gravity position detection unit that detects a center-of-gravity position of the legged robot is further provided, and the control unit is configured to detect the legged robot based on the foot part based on the detection result of the center-of-gravity position detection unit. The deviation between the target center-of-gravity position and the actual center-of-gravity position may be calculated, and the gait data correction unit may correct the gait data so as to reduce the deviation.

  Furthermore, the distance detection unit is configured to output the foot signal from output signals of at least four distance sensors provided on the sole of the toe and at least two distance sensors provided on the sole of the heel. You may make it detect the distance of the sole of a flat part, and a road surface.

  A control method for a legged robot according to the present invention includes a torso, a leg connected to the torso, and a foot provided at a lower end of the leg, and the foot is a toe part. And a gait data including a target position / posture of the toe part and a target angle of the toe joint, and a control method for a legged robot that is connected to the toe part via a toe joint. The control step of driving and controlling the joint of the leg based on the detection detects the distance between the sole of the foot and the road surface, and corrects the target position and orientation of the toe based on the detection result. Based on the toe correction amount calculating step for calculating the toe portion correction amount and the toe joint correction amount for correcting the target angle of the toe joint, and based on the calculated toe portion correction amount and the toe joint correction amount, the steps A gait data correction step for correcting the condition data, and The amount calculating step, when the target angle of the toe joint is greater than or equal to a predetermined threshold value, is to hold the toe joint correction amount to a predetermined value.

  Thus, by calculating the toe joint correction amount and the toe joint correction amount independently, and maintaining the toe joint correction amount at a predetermined value when the target angle of the toe joint is equal to or greater than a predetermined threshold, Even when the joint is driven and the buttocks leave the floor and the toes stand on the toes, continuity of the toe joint correction amount can be ensured. For this reason, it is not necessary to ensure the continuity of the controlled variable using a useless low-pass filter or the like, and the occurrence of phase delay can be suppressed. Therefore, the moment necessary for stabilization can be obtained well from the foot portion against disturbance, and the control of walking stably while driving the toe joint is possible.

  According to the present invention, it is an object of the present invention to provide a legged robot that can stably walk while driving a toe joint against disturbance, and a control method therefor.

Embodiment 1 of the Invention
The legged robot according to the first embodiment detects the distance between the trunk, the leg connected to the trunk, the foot provided at the lower end of the leg, and the sole of the foot and the road surface. And a control unit that drives and controls the joints of the legs based on the gait data. The foot part is composed of a toe part and a heel part connected to the toe part via a toe joint. The gait data includes at least a target position / posture of the toe part and a target angle of the toe joint. Here, the control unit of the legged robot calculates a toe part correction amount for correcting the target position and orientation of the toe part and a toe joint correction amount for correcting the target angle of the toe joint based on the detection result of the distance detection unit. A toe correction amount calculation unit to calculate, and a gait data correction unit to correct the gait data based on the toe portion correction amount and the toe joint correction amount calculated by the toe correction amount calculation unit. The toe correction amount calculation unit of the legged robot holds the toe joint correction amount at a predetermined value while the buttocks are getting out of bed.

  In the walking motion of a legged robot, using the detection result of the distance detection unit, the sole imitation control that causes the sole of the foot to follow the road surface and the detection result of the torso posture detection unit are used. Stabilization control is realized by combining with the inverted pendulum control that inverts the posture. According to the legged robot according to the first embodiment, while the buttocks are getting out of bed, the toe joint correction amount is held at a predetermined value, so that the toe joint is driven and the buttocks get out of bed. Even when the toe stands on the toe part, the continuity of the toe joint correction amount can be ensured. For this reason, it is not necessary to ensure the continuity of the controlled variable using a useless low-pass filter or the like, and the occurrence of phase delay can be suppressed. Therefore, the moment necessary for stabilization can be obtained well from the foot against disturbance, and the toe joint can be driven while walking stably.

  FIG. 1 is a diagram showing an outline of the legged robot according to the first embodiment. The robot 100 has a body 10 and two legs connected to the body 10. In FIG. 1, only one leg 20 is shown, and the other leg is not shown. The body 10 includes a control unit 30 that controls the operation of the robot 100 (operation of each joint of the leg), an acceleration sensor 12 that detects the acceleration of the body, and an inclination angle (posture angle) of the body 10 with respect to the vertical direction. A posture angle sensor 14 for detection is provided.

  The leg portion 20 includes a hip joint 21, a knee joint 23, an ankle joint 25, a thigh link 22, a shin link 24, and a foot link 26 as a foot portion. The thigh link 22 and the shin link 24 are schematically shown by straight lines. The hip joint 21 connects the body 10 and the thigh link 22 so as to be swingable. The knee joint 23 connects the thigh link 22 and the shin link 24 in a swingable manner. The ankle joint 25 connects the shin link 24 and the foot link 26 in a swingable manner. A foot link 26 as a foot portion is provided at the lower end of the leg portion 20. The foot link 26 is a plate-like member, and the back surface (foot back surface) of the foot link is a flat surface.

  FIG. 2 is a diagram for explaining the configuration of the foot link 26 of the robot 100 according to the first embodiment. The foot link 26 includes a toe part 26 a and a heel part 26 b connected to the toe part 26 a via a toe joint 27. During the walking operation of the robot 100, the toe joint 27 can be driven to float the buttocks 26b while keeping the toe 26a in contact with the road surface. That is, the robot 100 can be erected by grounding only the toe portion 26a with the heel portion 26b floating.

  The foot link 26 is provided with a sole distance sensor 16 as a distance detection unit. The sole distance sensor 16 detects the distance between the back surface (foot back surface) of the foot link 26 and the ground contact surface S. As shown in FIG. 2, the toe portion 26a and the heel portion 26b are formed in a substantially rectangular shape when viewed from above. Four sole distance sensors 16a, 16b, 16c, and 16d are provided in the vicinity of the four corners of the toe portion 26a. Here, two sole distance sensors 16a and 16d are provided on the toe side of the toe portion 26a, and two sole distance sensors 16b and 16c are provided on the heel portion direction side. The sole distance sensors 16a and 16d detect the distance between the back surface of the foot and the ground contact surface S at a predetermined position in front of the toe portion 26a, and the sole distance sensors 16b and 16c detect the foot at a predetermined position behind the toe portion 26a. The distance between the back surface and the ground plane S is detected. In the heel part 26b, two sole distance sensors 16e and 16f are provided at two corners opposite to the toe part side. The sole distance sensors 16e and 16f detect the distance between the sole surface and the ground contact surface S at a predetermined position behind the heel part 26b. Therefore, the foot link 26 foot is determined based on the difference between the distance detected by the sole distance sensors 16a and 16d, the distance detected by the sole distance sensors 16b and 16c, and the distance detected by the sole distance sensors 16e and 16f. The inclination of the back surface with respect to the ground contact surface S can be obtained. Further, an impact absorbing member for absorbing an impact at the time of landing is provided between the foot link 26 and the road surface. The shock absorbing member is formed integrally with the sole distance sensor 16.

  Each joint incorporates a motor (not shown) and is driven based on a command from the control unit 30. By driving the motor, the links connected to the joint can be swung. The other leg, not shown, has the same structure as the leg 20. The controller 100 can walk the robot 100 by appropriately controlling the joints (specifically, joint angles) of the two legs.

  In FIG. 1, for convenience of explanation, the direction in which the robot 100 travels (front-rear direction) is the x-axis, the direction orthogonal to the horizontal direction (left-right direction) with respect to the direction in which the robot 100 travels is y-axis, The direction (vertical direction) extending in the vertical direction from the plane to be used is defined as the z axis, and an explanation will be given using an absolute coordinate system composed of these three axes. That is, in FIG. 1, the x-axis indicates the left-right direction toward the paper surface, the y-axis indicates the depth direction of the paper surface, and the z-axis indicates the vertical direction in the paper surface. The point Ob is identified and fixed to the body 10 of the robot 100. The point Of is identified and fixed to the foot link 26.

  The robot 100 is controlled based on gait data stored in the storage unit 50. The gait data includes a target position of the trunk 10 (target trunk position), a target posture angle of the trunk 10 (target trunk posture angle), a target position of the foot link 26 (target foot position), and a target of the foot link 26. Time series data of the posture angle (target foot posture angle) and the target angle of the toe joint 27 (target toe joint angle) are included. Here, as the target foot position and the target foot posture angle, the target position / posture angle of the toe portion 26a (target toe position, target toe posture angle) or the target position / posture angle of the heel portion 26b (target heel position, target heel position). Any one of the position angle and the posture angle may be used.

  The gait data is created so that the robot 100 can be stably walked by simulation or the like. That is, the target torso position, the target torso posture angle, the target foot position, the target foot posture angle, and the target toe joint angle are the same as those in the convex hull surrounded by the sole where the ZMP position of the robot 100 is in contact with the ground surface. Is set to satisfy the relationship. The created gait data is stored in the storage unit 50 of the robot 100. As will be described later, the control unit 30 controls each joint so that the actual body position and the like match the target body position and the like included in the gait data.

  The target body position is represented by the position of the specific point Ob with respect to the absolute coordinate system. In the case of using a body coordinate system having the specific point Ob as the origin, the target body posture angle is represented by the inclination of the body coordinate system with respect to the absolute coordinate system. The actual body posture angle can be detected by a posture angle sensor 14 provided in the body 10. The target foot position is represented by the position of the specific point Of with respect to the absolute coordinate system. The desired foot posture angle is represented by the angle of the sole surface with respect to the ground contact surface. When the foot coordinate system having the specific point Of as the origin is used, the desired foot posture angle may be expressed by the inclination of the foot coordinate system with respect to the absolute coordinate system. The actual foot posture angle can be detected by the sole distance sensor 16 provided in the foot link 26 as described later.

  FIG. 3 is a diagram for explaining the configuration of the control coordinate system of the robot 100 according to the first embodiment. In the robot 100 according to the first embodiment, a control coordinate system for controlling the foot link 26 is defined in the toe portion 26a. That is, as shown in FIG. 3A, a specific point Of is provided on the toe portion 26a, and the foot link 26 is controlled using a toe coordinate system having the specific point Of as the origin. For the gait data, a target toe position, a target toe posture angle, and a target toe joint angle are obtained in advance based on the target foot position and the target foot posture angle of the foot link 26 and stored in the storage unit 50. Is done. In the control of the foot link 26, after the position and orientation of the toe portion 26a are converted into the position and orientation of the heel portion 26b using the toe joint angle, the target angle of each joint is obtained by inverse kinematics. As shown in FIG. 3B, when a specific point Of is provided in the rear part of the foot link 26 corresponding to the heel part 26b, the time series data of the target body position and the target body posture angle are included. Control is performed by determining the target angle of each joint by inverse kinematics from the target trajectory of the waist coordinate system and the target trajectory of the foot coordinate system including the time series data of the target foot position and target foot posture angle .

  Next, details of the control system 1 of the robot 100 according to the first embodiment will be described. The control system 1 executes the inversion control and the sole scanning control. Inversion control is control in which the actual body position and posture angle coincide with the target body position and posture angle. Note that the center of gravity position may be used instead of the body posture angle. The sole-following control is a control in which the relative actual foot position and the actual foot posture angle viewed from the ground contact surface coincide with the target foot position and the desired foot posture angle, respectively.

  FIG. 4 is a functional block diagram showing a functional configuration of the control system 1. The control system 1 includes a control unit 30, a storage unit 50, an attitude angle sensor 14, a motor 15, a sole distance sensor 16, and the like.

  The storage unit 50 stores gait data 51 and road surface nominal position / inclination information 52. The gait data 51 includes time series data of the target body position, the target body posture angle, the target foot position, the target foot posture angle, and the target angle of the toe joint 27. Here, the toe position or the target heel position may be used as the target foot position, and either the target toe posture angle or the target heel posture angle may be used as the target foot posture angle. When the sole touches the ground contact surface on the gait data, the foot sole and the ground contact surface are in surface contact state, so the desired foot posture angle (virtual foot sole inclination relative to the virtual ground contact surface) is It is set to zero. Further, each target value on the gait data is determined so as to satisfy a relationship in which the ZMP position of the robot 100 is within the convex hull surrounded by the soles of the legs that are in contact with the ground. The road surface nominal position / inclination information 52 is information on the presence of the road surface on which the robot 100 moves, and indicates a reference value regarding the position / inclination of the road surface.

  The control unit 30 reads the gait data 51 and the like stored in the storage unit 50 and determines the joint angle of the leg 20 necessary to realize the posture of the robot 100 specified by the read gait data 51 and the like. calculate. Then, a signal based on the joint angle calculated in this way is transmitted to the motor 15. In addition, the control unit 30 receives a signal from the sensor and adjusts the driving amount of the motor.

  More specifically, the control unit 30 includes a sole copying control unit 61, an inversion control unit 62, a joint angle conversion unit 63, and each axis controller 64. In the control unit 30, a feedback control system based on a deviation between the actual body posture angle and the target body posture angle (an inverted control system by the inverted control unit 62), a relative actual foot posture angle and a target foot as viewed from the ground contact surface. A feedback control system based on the deviation of the flat posture angle (a scanning control system by the sole scanning control unit 61) is included. Hereinafter, regarding the deviation of the sole imitation control, the deviation related to the relative foot posture angle as viewed from the ground contact surface is shown.

  When the sole imprint control unit 61 makes the actual foot posture angle coincide with the target foot posture angle, for example, when the sole is in contact with the ground surface and the heel side is floating from the ground surface The foot link 26 is rotated in the direction in which the toe side of the foot link 26 is brought closer to the shin link 24. That is, the foot link 26 is rotated so as to maintain the surface contact between the foot back surface and the ground contact surface. The actual foot posture angle is obtained from the output values of the sole distance sensors 16a, 16b, 16c, and 16d provided in the foot link 26. Details of the sole copying control unit 61 will be described later.

  The inversion control unit 62 functions to maintain the body position / posture of the robot 100 at the target position / posture. The body position / posture is an actual body position and body posture angle, and the target position / posture is a target body position and body posture angle. The actual body posture angle is detected by a posture angle sensor 14 provided in the body 10. The posture angle sensor 14 includes, for example, a gyro that detects an angular velocity of the body 10, an integrator that integrates an output (angular velocity) of the gyro, and a triaxial acceleration sensor that detects a gravitational acceleration vector. The details of the inversion control unit 62 will be described later.

  The control unit 30 includes a toe correction amount calculation unit and a gait data correction unit (not shown). The toe correction amount calculation unit first calculates the deviation between the output value of the sole distance sensor 16 and the target value to be followed for the position and orientation of the toe part 26a and the angle of the toe joint 27, and corrects the gait data. Toe correction amount (toe part correction amount and toe joint correction amount) is calculated. The gait data correction unit calculates a toe target value correction amount from the toe portion correction amount calculated by the toe correction amount calculation unit and a scanning control target value correction amount described later. Then, based on the foot target value correction amount, the gait data is corrected so that the positional relationship between the sole and the road surface follows the target value.

  More specifically, the gait data (time series data of the target body position, the target body posture angle, the target toe position, the target toe posture angle, and the target toe joint angle) stored in the storage unit 50 as described below. It is corrected and input to the joint angle conversion unit 63. In FIG. 3, the body position / posture target value includes time-series data of the target body position and the target body posture angle. The toe position / posture target value includes time-series data of the target toe position and the target toe posture angle. The toe joint angle target value includes time-series data of the target toe joint angle. Further, instead of the target toe position and the target toe posture angle, the target heel position and the target heel posture angle may be used.

  The target body position stored in the storage unit 50 is corrected based on the deviation between the target body acceleration and the actual body acceleration, and then input to the joint angle conversion unit 63. The target body acceleration is obtained by differentiating the target body position twice. The actual body acceleration is detected by the acceleration sensor 12.

  The target toe position stored in the storage unit 50 is corrected based on the deviation between the target toe position and the actual toe position, and then input to the joint angle conversion unit 63. The actual toe position is detected by the sole distance sensor 16.

  The target body posture angle stored in the storage unit 50 is input to the joint angle conversion unit 63 as it is. At the same time, a deviation between the target body posture angle and the actual body posture angle (body posture angle deviation) is obtained. The body posture angle deviation is input to the inversion control unit 62, and a body correction angle for rotating the body in a direction to reduce the body posture angle deviation is calculated. The actual body posture angle is detected by the posture angle sensor 14. In FIG. 3, the trunk correction angle is a correction amount in the sole copying control unit 61, so the trunk correction angle is referred to as a scanning control target value correction amount.

  A deviation (toe posture angle deviation) between the target toe posture angle and the actual toe posture angle stored in the storage unit 50 is obtained. The actual toe posture angle is detected by the sole distance sensor 16. Further, a deviation between the target toe joint angle and the actual toe joint angle stored in the storage unit 50 (toe joint angle deviation) is obtained. The actual toe joint angle is detected by the sole distance sensor 16. A sole correction angle for rotating the foot in a direction to reduce the input angle (an angle obtained by adding the toe posture angle deviation, the toe joint angle deviation, and the torso correction angle) by the sole copying control unit 61 is obtained. It is done. The target toe posture angle stored in the storage unit 50 is input to the joint angle conversion unit 63 after the above-described foot correction angle is added (after correction with the foot correction angle). In FIG. 3, the foot correction angle is referred to as a foot target value correction amount.

  The gait data corrected as described above is input to the joint angle conversion unit 63. From these values, the joint angle conversion unit 63 calculates the target joint angle of each joint of the leg 20 by inverse kinematics calculation. Here, each target value is represented by a value with respect to the absolute coordinate system. The joint angle conversion unit 63 calculates the relative position between the toe and the torso from the difference between the target toe position and the target torso position, and from the difference between the target toe posture angle (corrected by the foot correction angle) and the target torso posture angle. Calculate the relative rotation angle between the toes and the torso. A target joint angle that realizes the calculated relative position and relative rotation angle is calculated.

  Each axis controller 64 specifies the drive amount of each motor 15 for driving the leg 20 based on the signal of the target joint angle transmitted by the joint angle conversion unit 63, and the motor 15 is driven by these drive amounts. A motor drive signal for driving the motor is transmitted to each motor. Thereby, the driving amount at each joint of the leg 20 is changed, and the movement of the robot 100 is controlled.

  Next, the inversion control unit 62 according to the first embodiment will be described in detail with reference to FIG. FIG. 5 is a functional block diagram showing a functional configuration of the inversion control unit 62. As illustrated in FIG. 5, the inversion control unit 62 includes an attitude deviation calculation unit 621, a controller 622, and a limiter 623.

  The inversion control unit 62 first calculates a deviation between the body posture target value (target body posture) and the body posture measurement value (actual posture detected by the posture angle sensor 14) in the posture deviation calculation unit 621. Based on the calculated body posture deviation, a predetermined controller 622 calculates a correction amount of the target relative position / target relative posture between the sole and the road surface used in the sole copying control.

  Next, the inversion control unit 62 determines whether or not the sole is peeled off the road surface based on the output value of the sole distance sensor 16. As a result of the determination, if the sole is not peeled off the road surface, the calculated target relative position / target relative posture is not corrected, and is output as a scanning control target value correction amount. On the other hand, when the sole is peeled off the road surface, the calculated correction amount is limited via the limiter 623. That is, the limiter 623 limits the magnitude of the target relative position / target relative posture correction amount. The limiter 623 outputs an allowable limit value when the input correction amount exceeds the allowable range. By providing the limiter 623, the scanning control target value correction amount input to the sole scanning control unit 61 is limited. This ensures that the scanning control system (the sole scanning control unit 61) acts more preferentially than the inverted control system (inverted control unit 62). Accordingly, it is possible to ensure that the scanning control system acts predominately and the foot back surface comes into surface contact with the ground contact surface.

  Next, the inversion control unit 62 corrects the target relative position / target relative posture between the sole and the road surface in the direction of reducing the posture deviation of the trunk based on the calculated correction amount. The corrected target relative position / target relative posture is output to the sole copying control unit 61 as a copying control target value correction amount.

  Next, the sole copying control unit 61 according to the first embodiment will be described in detail with reference to FIGS. FIG. 6 is a functional block diagram showing a functional configuration of the sole copying control unit 61. FIG. 7 is a flowchart for explaining the outline of the control processing by the sole copying control unit 61. FIG. 8 is a diagram for explaining the deviation of the foot link 26. FIG. 9 is a diagram illustrating an example of walking while driving the toe joint 27. As shown in FIG. 6, the sole copying control unit 61 includes a distance sensor target value calculation unit 611, a difference unit 612, a toe deviation calculation unit 613, an adder 614, and a compensator 615.

  The sole copying control unit 61 first determines whether or not the toe joint angle target value is greater than or equal to a predetermined threshold value (step S101). As a result of the determination, if the toe joint angle target value is smaller than the predetermined threshold value, it is recognized that the buttocks 26b are not getting out of bed, and the sole copying control unit 61 is based on the detection result of the sole distance sensor 16. The deviation between the toe position / posture target value and the actual toe position / posture in the coordinate system defined for the toe portion 26a (toe position / posture deviation), and the deviation between the target toe joint angle and the actual toe joint angle (toe joint angle deviation) Are calculated independently (step S102).

  Hereinafter, a method for calculating the toe position / posture deviation and the toe joint angle deviation will be described in detail. First, the foot imprint control unit 61, in the distance sensor target value calculation unit 611, the toe position / posture target value (the trajectory of the target toe position / posture angle) included in the gait data 51 and the road surface which is road surface presence information. From the nominal position / tilt information 52, the height target value of the sole distance sensor 16 is calculated. In other words, the target time series value of the sole distance sensor 16 is calculated from the trajectory data indicating the target position / posture angle of the toe portion 26a and the point (nominal position / inclination) where the toe portion 26a actually lands. To do. That is, the target output value of the sole distance sensor 16 is calculated. Instead of the nominal position / inclination, the output value of the target sole distance sensor 16 is calculated by calculating the landing position / posture of the foot link 26 from the landing position of one step of the robot 100. May be.

  Next, the sole copying control unit 61 uses the differencer 612 to calculate the deviation of the sole distance sensor 16 from the calculated target value of the sole distance sensor 16 and the measured value actually measured by the sole distance sensor 16. calculate. Then, the toe deviation calculating unit 613 calculates the relative position deviation / relative posture deviation between the sole of the toe part 26a and the road surface from the calculated deviation of the sole distance sensor 16. Further, the toe deviation calculation unit 613 calculates the toe joint angle deviation from the calculated deviation of the sole distance sensor 16.

  FIG. 8A is an example showing a case where the toe joint angle target value is equal to or smaller than a predetermined threshold (in the example shown in the figure, the toe joint angle target value is substantially 0, and the foot link 26 as a whole is on the road surface. ), The sole scanning control unit 61 calculates the toe position / posture deviation and the toe joint angle deviation from the deviation of the sole distance sensor 16. The toe position / posture deviation (roll, pitch, z) in the toe coordinate system is expressed as (Ψt, θt, Zt). Zt represents a deviation related to the measured height in the vertical direction. The toe joint angle deviation is expressed as θtoe.

  The toe position / posture deviation (Ψt, θt, Zt) is calculated based on the output results of the four sole distance sensors 16a to 16d provided on the sole of the toe portion 26a. More specifically, the approximation (Δz1, Δz2, Δz3, Δz4) of the output values of the sole distance sensors 16a to 16d is performed using approximation from the geometric relationship between the positions where the soles and the sole distance sensors 16 are arranged. ) And the conversion matrix corresponding to the deviation of each sole distance sensor 16, the toe position / posture deviation (Ψt, θt, Zt) can be uniquely determined.

  Regarding the toe joint angle deviation θtoe, the four sole distance sensors 16a to 16d provided on the sole of the toe portion 26a and the two sole distance sensors 16e and 16f provided on the sole of the heel portion 26b are provided. And calculate based on the output result. More specifically, the deviation (Δz1, Δz2, Δz3, Δz4) of the output values of the sole distance sensors 16a to 16f is calculated using approximation from the geometric relationship between the positions where the soles and the sole distance sensors 16 are arranged. , Δz5, Δz6) and the conversion matrix corresponding to the deviation of each sole distance sensor 16, the toe joint angle deviation θtoe can be uniquely determined.

  Returning to FIG. 7, the description will be continued. The sole copying control unit 61 calculates a toe part correction amount from the toe position / posture deviation from each deviation calculated in step S102, and calculates a toe joint correction amount from the toe joint angle deviation (step S103). Next, the gait data is corrected so as to realize the toe target value correction amount including the calculated toe correction amount (step S104). More specifically, in the sole copying control unit 61, the compensator 615 calculates a toe part correction amount from the toe position / posture deviation using a predetermined transfer function, and calculates the toe joint correction amount from the toe joint angle deviation. Calculate each. Here, the scanning control target value correction amount, which is an output from the inversion control unit 62, is added to the toe position / posture deviation by the adder 614, and the added result is input to the compensator 615. The scanning control target value correction amount is added to the toe joint angle deviation by the adder 614, and the added result is input to the compensator 615. The compensator 615 calculates a toe portion correction amount from the toe position / posture deviation to which the scanning control target value correction amount is added using a predetermined transfer function, and the toe joint angle to which the scanning control target value correction amount is added Each toe joint correction amount is calculated from the deviation. A correction amount including the calculated toe correction amount (toe portion correction amount and toe joint correction amount) is output as a toe target value correction amount, and the toe portion 26a is configured so that the deviation is reduced by the toe target value correction amount. The target position / posture and the target angle of the toe joint 27 are corrected.

  On the other hand, if the result of determination in step S101 is that the toe joint angle target value is greater than or equal to a predetermined threshold value, it is recognized that the heel part 26b is getting out of bed, and the sole copying control unit 61 performs the above-described process. Then, based on the detection result of the sole distance sensor 16, the toe position / posture deviation is calculated (step S105). Next, the foot imprint control unit 61 calculates a toe portion correction amount for actually correcting the gait data from the toe position / posture deviation calculated in step S105 (step S106).

  Next, the sole copying control unit 61 does not newly calculate the toe joint angle deviation from the deviation of the sole distance sensor 16, and retains the predetermined value as the toe joint correction amount (step S107). For this reason, while the buttocks 26b are getting out of bed, the toe joint angle deviation is not calculated, and the toe joint correction amount does not change and remains constant. In this manner, by determining whether or not the buttocks 26b are out of bed according to the target angle of the toe joint 27, switching is performed so that the toe joint correction amount is held only by recognizing the driving of the toe joint 27. Can respond well.

  The determination as to whether or not the buttocks 26b are getting out of bed is not limited to the configuration that is performed according to the recognition of the driving of the toe joint 27. For example, the buttocks 26b is getting out according to the target angle of the toe joint 27. The period may be obtained and stored in advance, and a predetermined value may be held as the toe joint correction amount within the bed leaving period.

  FIG. 8B is an example showing a case where the toe joint angle target value is smaller than a predetermined threshold (in the example shown in the figure, the heel portion 26b is off the floor). Only the toe position / posture deviation is calculated from the deviation of the back distance sensor 16, and the toe joint angle deviation is not calculated, and a predetermined value is held as the toe joint correction amount. A predetermined constant value in the case where the toe joint angle deviation θtoe is not newly calculated is represented as const.

  As described above, the toe position / posture deviation (Ψt, θt, Zt) is calculated based on the output results of the four sole distance sensors 16a to 16d provided on the soles of the toe portion 26a.

  On the other hand, with respect to the toe joint angle deviation θtoe, a new deviation is not calculated based on the output result of the sole distance sensor 16 (that is, θtoe = const), and while the buttocks 26b are getting out of bed. For example, the toe joint correction amount in the immediately preceding control cycle among the toe joint correction amounts before the time when the buttocks 26b leaves the bed is held as the toe joint correction amount. Thus, while the buttocks 26b are getting out of bed, the continuity of the toe joint corrections can be easily ensured by holding the toe joint corrections in the control cycle immediately before the buttocks 26b get out of bed. .

  FIG. 9 is a diagram illustrating a state where the legged robot 100 according to the first embodiment walks while driving the toe joint 27. As shown in the figure, from the latter half of the supporting leg stage, by driving the toe joint 27 so that the heel part 26b is lifted from the road surface, the stride during walking can be increased, and it becomes easy to walk at high speed. The driven toe joint angle is restored to the original during the swing leg period, and when the foot link 26 is landed on the road surface, it is controlled to land from the heel part 26b. In the example shown in FIG. 8, in the latter half of the supporting leg period shown in FIGS. 8B and 8C, the toe joint angle target value is equal to or greater than a predetermined threshold value, and the toe joint correction amount is held at a predetermined value. Then, over the period shown in FIGS. 8D to 8E, the toe joint angle deviation is set to a predetermined constant so that the toe joint correction amount is set to 0 and the driven toe joint angle is returned to the original position. To do.

  As described above, in the legged robot 100 according to the first embodiment, the foot part 26 provided at the lower end of the leg part 20 is connected to the toe part 26a via the toe part 26a and the toe joint 27. It is comprised from the connected collar part 26b. The gait data for driving and controlling the joint of the leg 20 includes at least the target position / posture of the toe 26a and the target angle of the toe joint. Here, the control unit 30 of the legged robot 100 corrects the toe part correction amount for correcting the target position and orientation of the toe part 26 a and the target angle of the toe joint 27 based on the detection result of the sole distance sensor 16. The toe joint correction amount is calculated, and the gait data is corrected based on the calculated toe part correction amount and the toe joint correction amount. The control unit 30 of the legged robot 100 is characterized in that the toe joint correction amount is held at a predetermined value while the heel part 26b is getting out of bed.

  According to the legged robot 100 according to the first embodiment, the toe portion correction amount and the toe joint correction amount are calculated independently, and the toe joint correction amount is set to a predetermined value while the buttocks 26b are getting out of bed. By holding the toe joint 27, the continuity of the toe joint correction amount can be guaranteed even when the toe joint 27 is driven and the buttocks 26b get out of the floor and stand on the toe by the toe part 26a. For this reason, it is not necessary to ensure the continuity of the controlled variable using a useless low-pass filter or the like, and the occurrence of phase delay can be suppressed. Therefore, the moment necessary for stabilization can be obtained well from the foot portion against disturbance, and the toe joint 27 can be driven while walking stably.

Other embodiments.
In the embodiment described above, the robot 100 includes two legs, but the present invention is not limited to this. A legged robot having at least two legs, each having a foot at the lower end of each leg, and at least three distance sensors on the sole of the foot. The invention can be applied.

  It should be noted that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the gist of the present invention already described.

It is a block diagram of the legged robot which concerns on Embodiment 1 of this invention. It is a block diagram of the foot link of the legged robot which concerns on Embodiment 1 of this invention. It is a figure for demonstrating the structure of the control coordinate system of the legged robot which concerns on Embodiment 1 of this invention. It is a functional block diagram which shows the structure of the legged robot which concerns on Embodiment 1 of this invention. It is a functional block diagram which shows the structure of the inversion control part of the legged robot which concerns on Embodiment 1 of this invention. It is a functional block diagram which shows the structure of the sole copying control part of the legged robot which concerns on Embodiment 1 of this invention. It is a flowchart which shows the process which the control part of the legged robot which concerns on Embodiment 1 of this invention performs. It is a figure for demonstrating the deviation of the foot link of the legged robot which concerns on Embodiment 1 of this invention. It is a figure which illustrates a mode that the legged robot which concerns on Embodiment 1 of this invention walks, driving a toe joint.

Explanation of symbols

1 control system,
10 torso,
12 acceleration sensor, 14 posture angle sensor, 15 motor, 16 distance sensor 20 leg, 21 hip joint, 22 thigh link, 23 knee joint, 24 tibi link,
25 ankle joint, 26 foot link, 26a toe part, 26b buttocks, 27 toe joint,
30 control unit, 50 storage unit,
51 gait data, 52 road surface nominal position / tilt,
60 arithmetic processing units, 61 copying control unit, 62 inversion control unit, 63 joint angle conversion unit,
64 Each axis controller,
611 Distance sensor target value calculator, 613 toe deviation calculator, 615 compensator,
621 Attitude deviation calculator, 622 controller, 623 limiter,
100 robot

Claims (8)

A torso, a leg connected to the torso, a foot provided at a lower end of the leg, a distance detecting unit for detecting a distance between the sole of the foot and the road surface, and gait data A control unit that drives and controls the joints of the legs based on
The foot part is composed of a toe part and a heel part connected to the toe part via a toe joint,
The gait data includes a target position and posture of the toe part and a target angle of the toe joint,
The controller is
A toe correction amount calculation unit for calculating a toe part correction amount for correcting the target position and orientation of the toe part and a toe joint correction amount for correcting the target angle of the toe joint based on the detection result of the distance detection unit; ,
A gait data correction unit that corrects the gait data based on the toe part correction amount and the toe joint correction amount calculated by the toe correction amount calculation unit;
The toe correction amount calculation unit
While the buttocks are getting out of bed, the toe joint correction amount is maintained at a predetermined value. The toe correction amount calculation unit
The legged robot according to claim 1, wherein when the target angle of the toe joint is equal to or greater than a predetermined threshold, the toe joint correction amount is held at a predetermined value. The toe correction amount calculation unit
While the buttocks are getting out of bed, the toe joint correction amount in the immediately preceding control cycle is held as the toe joint correction amount among the toe joint correction amounts before the time when the buttocks gets out of bed. Item 3. The legged robot according to item 1 or 2. Defining a toe coordinate system for controlling the foot on the toe,
The toe correction amount calculation unit
Based on the detection result of the distance detection unit, a deviation between the target position and orientation of the toe part in the toe coordinate system and an actual position and orientation is calculated, and the deviation is multiplied by a predetermined gain to obtain the toe part correction amount. Calculate
4. The toe joint correction amount is calculated by calculating a deviation between a target angle of the toe joint and an actual angle, and multiplying the deviation by a predetermined gain. 5. Legged robot. A body posture detection unit for detecting the posture of the body;
The controller is
Based on the detection result of the fuselage posture detection unit, the deviation between the target posture of the fuselage and the actual posture is calculated,
The gait data correction unit
The legged robot according to claim 1, wherein the gait data is corrected so as to reduce the deviation. A centroid position detector for detecting a centroid position of the legged robot;
The controller is
Based on the detection result of the center-of-gravity position detection unit, the deviation between the target center-of-gravity position of the legged robot and the actual center-of-gravity position with respect to the foot is calculated,
The gait data correction unit
The legged robot according to claim 1, wherein the gait data is corrected so as to reduce the deviation. The distance detection unit is configured to output from the output signals of at least four distance sensors provided on the soles of the toes and at least two distance sensors provided on the soles of the heels. The legged robot according to any one of claims 1 to 6, wherein a distance between the sole and the road surface is detected. A torso, a leg connected to the torso, and a foot provided at a lower end of the leg, and the foot is connected to the toe via a toe and a toe joint. A legged robot control method comprising a heel part,
Based on the gait data including the target position and posture of the toe part and the target angle of the toe joint, the control step of driving and controlling the joint of the leg part includes:
The toe joint that detects the distance between the sole of the foot and the road surface, and corrects the target position and orientation of the toe part based on the detection result and the target angle of the toe joint A toe correction amount calculating step for calculating a correction amount;
A gait data correction step for correcting the gait data based on the calculated toe part correction amount and the toe joint correction amount,
In the toe correction amount calculating step,
A control method for a legged robot, wherein the toe joint correction amount is held at a predetermined value when a target angle of the toe joint is equal to or greater than a predetermined threshold.

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