Legged robot

Abstract

To provide a legged robot whose balance is maintained more reliably than conventional ones.SOLUTION: A legged robot according to the present invention is provided with a hybrid controller 20A including: an automatic balance controller 10A that outputs a first torque command related to automatic balance maintenance; and a leg controller 21 that outputs a second torque command based on arbitrary control. The automatic balance controller 10A includes: a horizontal-direction controller 11 that outputs a third torque command related to torque to be generated by an actuator of a joint of a leg 31 so that a trunk is located substantially vertically above a sole; and a pressure-center controller 12 that outputs a fourth torque command related to torque to be generated by the actuator of the joint of the legs 31 so that a pressure-center point of a floor reaction force received by the sole from ground 50 is located at a predetermined position in the sole. The automatic balance controller outputs, as a first torque command, a torque command indicating a sum of amounts of torque indicated by the third torque command and the fourth torque command.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a legged robot, and more particularly to a legged robot equipped with a hybrid controller including a leg controller that controls the legs based on instructions from an operator and an auto-balance controller that automatically maintains balance. [Background technology]

[0002] There is a desire to realize legged robots that can perform various tasks in place of humans in dangerous environments, but many challenges remain before they can be fully automated. For this reason, development of remote-controlled legged robots is underway. Known methods for operating remote-controlled legged robots include, for example, a method in which an operator commands a walking path via a graphical user interface (GUI) as described in Non-Patent Document 1, and a method in which the operator's movements, captured by motion capture, are reflected in the robot as described in Non-Patent Document 2.

[0003] Legged robots generally have unstable mechanisms with many degrees of freedom, and walking, one of their basic movements, poses a high risk of tipping over. To address this issue, a method for automatically and autonomously generating walking patterns in real time, as described in Non-Patent Documents 3 and 4, is effective. However, this method does not allow the operator to control the leg movements required for walking one by one. For this reason, legged robots that employ this method may not be able to change foot positions at the operator's discretion, which is necessary when walking on uneven terrain such as construction sites or disaster sites.

[0004] Thus, it is desirable for a remote-controlled legged robot to be equipped with a controller that moves the legs as intended by the operator and automatically maintains the balance of the entire robot. An example of such a legged robot is described in Patent Document 1. This legged robot is equipped with a torque command-based autobalance controller (i.e., an autobalance controller that outputs torque commands to the ankle joints). This autobalance controller is configured to be usable in combination with any leg controller that outputs torque commands corresponding to the operator's commands. This autobalance controller allows the operator to move the legs as intended, as long as the output of the leg controller does not interfere with the autobalance controller, i.e., the autobalance controller does not disrupt the balance achieved by the autobalance controller. [Prior art documents] [Non-patent literature]

[0005] [Non-Patent Document 1] S. Nakaoka, M. Morisawa, K. Kaneko, S. Kajita, and F. Kanehiro: “Development of an indirect-type teleoperation interface for biped humanoid robots,” Proceedings of 2014 IEEE / SICE International Symposium on System Integration, pp.590-596, 2014. [Non-patent document 2] I. Almetwally and M. Mallem: “Real-time tele-operation and tele-walking of humanoid robot NAO using Kinect Depth Camera,” Proceedings of 2013 10th IEEE International Conference on Networking, Sensing and Control, pp.463-466, 2013. [Non-patent document 3] J. Ding, M. Yang, J. Zhou, D. Yao, and X. Xiao: “Robust real-time walking pattern generation with dynamical consistency: An analytical method combined with optimal solution,” Proceedings of 2017 IEEE International Conference on Robotics and Biomimetics, pp.1806-1811, 2017. [Non-patent document 4] T. Sato, S. Sakaino, and K. Ohnishi: “Real-time walking trajectory generation method with three-mass models at constant body height for three-dimensional biped robots,” IEEE Transactions on Industrial Electronics, vol.58, no.2, pp.376-383, 2011. [Patent documents]

[0006] [Patent Document 1] Patent No. 5268107 Summary of the Invention [Problem to be solved by the invention]

[0007] However, the autobalancing controller for the legged robot described in Patent Document 1 was sometimes unable to maintain balance in various situations, including when a sustained external force was applied to the robot.

[0008] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a legged robot that can maintain balance more reliably than conventional robots. [Means for solving the problem]

[0009] In order to solve the above problems, a first legged robot according to the present invention is a robot including a trunk, legs connected to the trunk, and a hybrid controller that controls the legs, The leg includes a foot having a sole that can contact the ground, a leg, and at least one joint; the hybrid controller includes an auto-balance controller that outputs a first torque command related to automatic maintenance of balance, and a leg controller that outputs a second torque command based on arbitrary control, and is configured to output a torque command indicating the sum of the torque amounts indicated by the first torque command and the second torque command as a command related to the torque to be generated by the actuator of the joint; the autobalance controller includes a horizontal direction controller that outputs a third torque command and a pressure center controller that outputs a fourth torque command, and is configured to output a torque command that indicates a sum of torque amounts indicated by the third torque command and the fourth torque command as a first torque command; The third torque command is a command regarding the torque that the actuator of the joint should generate so that the torso is positioned approximately vertically above the sole of the foot, and the fourth torque command is a command regarding the torque that the actuator of the joint should generate so that the center of pressure of the floor reaction force that the sole of the foot receives from the ground is at a predetermined position within the sole of the foot, and the amount of torque indicated by the fourth torque command is limited so that it does not become infinitely large.

[0010] The autobalancing controller of the first legged robot may further include a vertical direction controller that outputs a fifth torque command, and may be configured to output, as the first torque command, a torque command that indicates the sum of the torque amounts indicated by the third torque command, the fourth torque command, and the fifth torque command. The fifth torque command is a command related to the torque that the actuator of the joint should generate so that the position of the trunk in the approximately vertical direction approaches a predetermined neutral state, or a command related to the torque that the actuator of the joint should generate so that the displacement of the joint approaches a predetermined neutral state.

[0011] The center of pressure controller of the first legged robot may be configured to limit the torque amount indicated by the fourth torque command by using an imperfect integrator, which may be an imperfect integrator with a limiter that limits the output.

[0012] In order to solve the above problems, a second legged robot according to the present invention is a robot including a trunk, a plurality of legs connected to the trunk, and a hybrid controller that controls the plurality of legs, Each of the plurality of legs includes a foot having a sole capable of contacting the ground, a leg, and at least one joint; the hybrid controller includes an auto-balance controller that outputs a first torque command related to automatic balance maintenance for each leg, and a leg controller that outputs a second torque command based on arbitrary control for each leg, and is configured to output a torque command indicating the sum of the torque amounts indicated by the first torque command and the second torque command for the same leg as a command related to the torque to be generated by the actuator of the joint included in that leg; the autobalance controller includes a horizontal direction controller that outputs a third torque command for each leg and a center of pressure controller that outputs a fourth torque command for each leg, and is configured to output a torque command that indicates the sum of the torque amounts indicated by the third torque command and the fourth torque command for the same leg as a first torque command for that leg; The third torque command is a command regarding the torque that the actuator of the joint should generate so that the torso is positioned approximately vertically above the sole of the foot, and the fourth torque command is a command regarding the torque that the actuator of the joint should generate so that the center of pressure of the floor reaction force that the sole of the foot receives from the ground is at a predetermined position within the sole of the foot, and the amount of torque indicated by the fourth torque command is limited so that it does not become infinitely large.

[0013] The autobalancing controller of the second legged robot may further include a vertical direction controller that outputs a fifth torque command for each leg, and may be configured to output a torque command indicating the sum of the torque amounts indicated by the third torque command, the fourth torque command, and the fifth torque command for the same leg as the first torque command for that leg. The fifth torque command is a command regarding the torque that the actuator of the joint should generate so that the position of the trunk in the approximately vertical direction approaches a predetermined neutral state, or a command regarding the torque that the actuator of the joint should generate so that the displacement of the joint approaches a predetermined neutral state.

[0014] The autobalancing controller of the second legged robot may further include an external force component extraction unit that extracts the external force components of the third torque command, the fourth torque command, and the fifth torque command, and may be configured to output a torque command that indicates the sum of the torque amounts indicated by the external force component of the third torque command, the external force component of the fourth torque command, and the external force component of the fifth torque command for the same leg as the first torque command for that leg.

[0015] The autobalancing controller of the second legged robot may further include a ground contact controller that outputs a sixth torque command for each leg, and an internal force component extractor that extracts an internal force component of the sixth torque command, and may be configured to output, as a first torque command for the leg, a torque command that indicates the sum of the torque amounts indicated by the external force component of the third torque command, the external force component of the fourth torque command, the external force component of the fifth torque command, and the internal force component of the sixth torque command for the same leg. The sixth torque command is a command regarding the torque that should be generated by the actuator of the joint to keep the sole of the foot in contact with the ground.

[0016] The center of pressure controller of the second legged robot may be configured to limit the torque amount indicated by the fourth torque command by using an imperfect integrator, which may be an imperfect integrator with a limiter that limits the output. [Effects of the Invention]

[0017] According to the present invention, it is possible to provide a legged robot that maintains balance more reliably than conventional robots. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 1 is a control block diagram of a legged robot according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a schematic diagram for explaining horizontal direction control according to the present invention. [Figure 3] FIG. 4 is a schematic diagram for explaining the center of pressure control of the present invention. [Figure 4] FIG. 10 is a control block diagram of a legged robot according to a second embodiment of the present invention. [Figure 5] FIG. 2 is a schematic diagram for explaining vertical direction control according to the present invention. [Figure 6] FIG. 10 is a control block diagram of a legged robot according to a third embodiment of the present invention. [Figure 7] FIG. 10 is a control block diagram of a legged robot according to a fourth embodiment of the present invention. [Figure 8] FIG. 2 is a schematic diagram for explaining ground contact control according to the present invention. [Figure 9] FIG. 2 is a schematic diagram for explaining an external force component and an internal force component. DETAILED DESCRIPTION OF THE INVENTION

[0019] First, various definitions and terms used in this specification will be explained.

[0020] [1. Various definitions] In this specification, we define an m × n zero matrix as O m×n , n-dimensional zero vector o n , n × n identity matrix I n ,For any three-dimensional vector x, the 3×3 skew-symmetric matrix that satisfies ,equation (1) is denoted as [a×].

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[0021] In this specification, the function ROT(q, p) is defined as in equation (2).

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[0022] In this specification, the generalized saturation function gsat is defined as shown in equation (3).

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[0023] [2. Incomplete integral] An inexact integral is an operation expressed by equation (4) or equation (5).

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[0024] [3.Kinematics] As will be explained in detail later, a legged robot according to the present invention includes a trunk and at least one leg connected to the trunk, and the leg includes a foot having a sole that can come into contact with the ground and apply torque, a leg portion, and at least one joint.

[0025] In this specification, the coordinate system set for the body (body coordinate system) is represented as B, and the coordinate system set for the foot (foot coordinate system) is represented as F. If a legged robot has two legs (left leg and right leg), the coordinate system set for the foot of the left leg (left foot coordinate system) is represented as F. L , the coordinate system set for the foot of the right leg (right foot coordinate system) is F R In addition, if the legged robot has n legs, the coordinate system set at the foot of the kth leg (k∈{1, , n}) is expressed as F k However, when there is no need to distinguish between the multiple foot coordinate systems that have been set, it may simply be expressed as foot coordinate system F.

[0026] In this specification, a 3 × 3 posture matrix that indicates the posture of the foot coordinate system F as seen from the body coordinate system B is defined as B R F Also, the position vector of the foot as seen from the body coordinate system B is B r FB (6), the generalized velocity vector of the foot seen from the body coordinate system BB v FB is expressed as equation (7).

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[0027] In this specification, for example, if a leg includes m joints, the angle vector q of the m joints is F is expressed as equation (8).

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[0028] [4.Statics] In this specification, for example, if a leg includes m joints, the torque vectors τ of the m joints are F (11), the generalized force vector applied by the leg to the foot expressed in the body coordinate system B B φ FB is expressed as equation (12).

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[0029] Torque vector τ F and the generalized force vector B φ FB The relational expression (13) holds between B J FB is the appropriate Jacobian matrix mentioned above.

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[0030] The generalized force vector applied by the leg (leg part) to the body expressed in the body coordinate system B is B φ BF Then, the generalized force vector B φ BF and the generalized force vector B φ FB The relation (14) holds between

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[0031] [5. External and internal force components] [5-1.Definition] In this specification, when a legged robot has n legs connected to its trunk and in contact with the ground, the generalized force vector sequence [ B φ F1B T ,···, B φ FnB T ] T The external force component based on a certain distance criterion is defined as "the generalized force vector sequence [ B φ F1B T ,···,B φ FnB T ] T The distance norm is defined as "the vector sequence with the smallest norm based on the distance criterion among an infinite number of vector sequences of generalized forces that can apply to the trunk a generalized force equivalent to the distance norm of the leg." Furthermore, in this specification, the distance norm is defined as "the vector sequence of generalized forces that each leg applies to the trunk based on a certain distance criterion, B φ F1B T ,···, B φ FnB T ] T The internal force components of the "generalized force vector sequence [ B φ F1B T ,···, B φ FnB T ] T It is defined as "the force component minus the external force component."

[0032] [5-2. Generalized forces generated by the legs and generalized forces acting on the torso] Generalized force vectors applied by each leg to the foot expressed in the body coordinate system B B φ F1B ,···, B φ FnB , and the generalized force vectors exerted by each leg on the body, expressed in the body coordinate system B. B φ B1L ,···, B φ BnR As explained using equation (14), the relational expression (16) holds between these.

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[0033] When the foot of each leg is on the ground, the generalized resultant force vector that each leg exerts on the trunk expressed in the trunk coordinate system B is B φ BG is expressed as in equation (18).

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[0034] [5-3. Extraction of external and internal force components] The aforementioned generalized force vector sequence [ B φ F1B T ,···, B φ FnB T ] T As explained using equation (18), the generalized resultant force vector expressed by equation (21) is B φ BG Add to the body.

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[0035] This generalized resultant force vector B φ BG The generalized force vector sequence φ required to realize * =[ B φ * F1B T ,···, B φ * FnB T ] T , i.e., B φ BG =-Πφ * A generalized force vector sequence φ that satisfies * There are not only φ but also an infinite number of φ. In the present invention, the smallest possible one is selected from the infinite number of φ. This selection is performed by * Using the p×6n matrix U, we can calculate the index of the size of ||Uφ *If we define ||, then we can use equation (22) to obtain ||Uφ * A generalized force vector sequence φ that minimizes || * (Hereafter, this is called φ ex This is equivalent to finding (where .

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[0036] In this specification, the matrix Φ ex is the “external force component extraction matrix”, φ ex is called the "external force component" of φ. In the present invention, φ in Equation (26) in is called the "internal force component" of φ.

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[0037] In this specification, the external force component extraction matrix Φ ex Using φ to external force component φ ex or internal force component φ inThe process of finding this is called "extraction." This extraction can be summarized in the form of a function, as shown in equations (27) and (28).

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[0038] In addition, the generalized force vector sequence [ B φ F1B T ,···, B φ FnB T ] T The generalized force vector that each leg exerts on the body from B φ FkB (k∈{1, ,n}) is obtained. Then, as shown in equation (13), this generalized force vector B φ FkB Joint torque vector τ of each leg Fk (k∈{1, ,n}) is obtained. More specifically, the joint torque vector τ Fk is calculated as shown in equation (29).

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[0039] [5-4. Simple Extraction Example 1] The concept of extracting external and internal force components is easier to understand if we simplify it to a legged robot with a torso and two legs (left and right legs) as shown in Figure 9. In Figure 9, there is a mass point corresponding to the torso in one-dimensional space, and on the left and right sides of this are attached actuators corresponding to the left and right legs. In this extraction example, it is assumed that the rated outputs of the left and right actuators are the same.

[0040] The force applied by the left leg actuator to the torso is f L , the force exerted by the right leg actuator on the torso is f R Then, the resultant force acting on the body is f B is f L +f R In this case, the matrix Π is [1,1]. Also, in this case, the generalized force vector sequence [f L ,f R ] T The size of √(f L 2 +f R 2 ), the matrix U is expressed as in equation (31).

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[0041] From these facts, the external force component extraction matrix Φ ex is calculated as shown in equation (32).

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[0042] For example, the force command value for each leg is [f L =4N,f R =2N], the external force component is [f L,ex =3N,f R,ex =3N] and the internal force component is [f L,in =1N,f R,in =-1N]. Also, the force command value for each leg is [f L =4N,f R =-2N], the external force component is [f L,ex =1N,f R,ex =1N] and the internal force component is [f L,in =3N,f R,in =-3N]. The external force component can be said to be the force command value for each leg averaged and divided equally between both legs. The internal force component is a component that compresses (or pulls) the trunk with equal force from both sides, and does not contribute to the movement of the trunk.

[0043] [5-5. Simple Extraction Example 2] In this extraction example, the rated output of the left leg actuator is assumed to be twice that of the right leg actuator. In this case, the generalized force vector sequence [f L ,f R ] T The size of √((fL / 2) 2 +f R 2 ) is preferably used to evaluate the matrix U and the external force component extraction matrix Φ ex are expressed as equations (35) and (36).

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[0044] For example, the force command value for each leg is [f L =4N,f R =2N], the external force component is [f L,ex =4.8N,f R,ex =1.2N] and the internal force component is [f L,in =-0.8N,f R,in =0.8N]. Also, the force command value for each leg is [f L =4N,f R =-2N], the external force component is [f L,ex =1.6N,f R,ex =0.4N], and the internal force component is [f L,in =2.4N,f R,in =-2.4N]. The external force component can be said to be the force command value for each leg, averaged after taking into account the rated output of the actuator as a distance standard, and then divided equally between both legs. Also, as in Extraction Example 1, the internal force component is a component that compresses (or pulls) the trunk from the left and right with the same force, and does not contribute to the movement of the trunk.

[0045] Next, first to fourth embodiments of the legged robot according to the present invention will be described with reference to the accompanying drawings.

[0046] [6. First Example] [6-1. Overall composition] Fig. 1 shows a legged robot 30A according to a first embodiment of the present invention. The legged robot 30A includes a body (not shown in Fig. 1), one leg 31 connected to the body, and a hybrid controller 20A that controls the leg 31. The hybrid controller 20A may be integrated into the body, or may be provided at a location separate from the body.

[0047] The leg 31 includes a foot 33 having a sole that can apply torque in contact with the ground 50, a leg 32, and at least one joint. At least one load cell that measures torque applied to the foot 33 from the ground 50 is provided on the sole of the foot 33. In addition, an actuator is provided at each joint.

[0048] The hybrid controller 20A includes a leg controller 21 that outputs torque commands in response to commands from an operator, and an autobalance controller 10A that outputs torque commands related to automatic maintenance of balance, and the autobalance controller 10A further includes a horizontal direction controller 11 and a center of pressure controller 12. An example of the leg controller 21 is a force-propagating bilateral controller proposed by the inventor of the present application in Japanese Patent Application No. 2014-093322 and the like.

[0049] The leg controller 21 outputs a torque command in response to force information sent from the leg operating device 40 operated by the operator. B φ FB,O In other words, the leg controller 21 outputs a torque command based on an arbitrary control. B φ FB,O The leg controller 21 also outputs the angle vector q of the joint included in the leg 31. FThe leg operation device 40 may be integrated into the legged robot 30A or may be provided at a location remote from the legged robot 30A. When the legged robot 30A is a large working machine or the like equipped with a passenger seat, the leg operation device 40 can be said to be integrated into the legged robot 30A. The torque command B φ FB,O corresponds to the "first torque command" of the present invention.

[0050] The horizontal direction controller 11 calculates the angle vector q of the joints included in the leg 31. F Torque command obtained from B φ FB,A Torque command is output. B φ FB,A This corresponds to the "third torque command" of the present invention. B φ FB,A The output of the .

[0051] The center of pressure controller 12 calculates the angle vector q of the joints included in the leg 31. F and a ground reaction torque vector n related to the reaction force applied by the ground 50 to the foot 33. FG Torque command obtained from B φ FB,B Torque command is output. B φ FB,B This corresponds to the "fourth torque command" of the present invention. B φ FB,B The output of the .

[0052] The autobalance controller 10A is B φ FB,A and torque command B φ FB,B The torque command indicates the sum of the torque amounts indicated by the torques. This torque command corresponds to the "second torque command" of the present invention.

[0053] The hybrid controller 20A controls the torque command output from the leg controller 21. B φFB,O (first torque command) and the torque command (second torque command) output by the autobalance controller 10A. B φ FB is output as a command relating to the torque to be generated by the actuator of the joint included in the leg 31.

[0054] In this embodiment, the relationship between the torque commands output by the controllers is expressed as in equation (39).

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[0055] [6-2. Horizontal direction controller] As shown in FIG. 2, the horizontal direction controller 11 outputs a torque command indicating the amount of torque that the actuator of each joint should generate in order to position the body 34 of the legged robot 30A substantially vertically above the sole of the foot 33. B φ FB,A The horizontal direction controller 11 can also be said to be a controller for controlling the positional relationship between the body 34 and the feet 33 in the approximately horizontal direction to be a predetermined positional relationship.

[0056] The horizontal direction controller 11 uses the torque command calculated by the equation (40) B φ FB,A Output.

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[0057] Torque Vector F n BF,Acan be expressed as in equation (41).

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[0058] [6-3. Pressure Center Controller] As shown in FIG. 3, the center of pressure controller 12 outputs a torque command indicating the amount of torque that the actuator of each joint should generate in order to keep the center of pressure (called "CoP", hereinafter also referred to as "ZMP") of the floor reaction force that the sole of the foot 33 receives from the ground 50 at a predetermined position within the sole of the foot. B φ FB,B Output.

[0059] The center of pressure controller 12 calculates the floor reaction torque vector F expressed in the foot coordinate system F obtained from the load cell attached to the sole of the foot. F n FG Using this, the incomplete integration expressed by equation (42) is performed.

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[0060] The center of pressure controller 12 generates a torque command relating to the amount of torque that the leg 32, expressed in the foot coordinate system F, should apply to the foot 33 based on a so-called ankle strategy. F φ FB,B is determined as shown in equation (43).

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[0061] For example, if the foot 33 has a toe and a heel, the foot 33 and the leg 32 are connected via an ankle joint, and the ZMP is continuously shifted from a predetermined position in the sole toward the toe due to an external force applied to the trunk 34, the center of pressure controller 12 generates a torque in the leg 31 (particularly, the actuator of the ankle joint) that tilts the trunk 34 backward (toward the heel). This causes the ZMP to approach the predetermined position in the sole.

[0062] According to the legged robot 30A of this embodiment, the horizontal direction control and the center of pressure control are performed simultaneously in parallel, making it possible to maintain balance more reliably than ever before.

[0063] [7. Second Example] [7-1. Overall structure] 4 shows a legged robot 30B according to a second embodiment of the present invention. The legged robot 30B differs from the legged robot 30A in that the legged robot 30B is equipped with a hybrid controller 20B instead of the hybrid controller 20A, but is otherwise the same as the legged robot 30A.

[0064] Hybrid controller 20B differs from hybrid controller 20A in that it includes autobalance controller 10B instead of autobalance controller 10A, but is common to hybrid controller 20A in other respects. Also, autobalance controller 10B differs from autobalance controller 10A in that it further includes vertical direction controller 13, but is common to autobalance controller 10A in other respects (particularly, the inclusion of horizontal direction controller 11 and center of pressure controller 12).

[0065] The vertical direction controller 13 calculates the angle vector q of the joints included in the leg 31. F Torque command obtained from B φ FB,C Torque command is output. B φ FB,C This corresponds to the "fifth torque command" of the present invention. B φ FB,C The output of the .

[0066] The autobalance controller 10B receives a torque command B φ FB,A , torque command B φ FB,B and torque command B φ FB,C The torque command indicates the sum of the torque amounts indicated by the torques. This torque command corresponds to the "second torque command" of the present invention.

[0067] The hybrid controller 20B controls the torque command output by the leg controller 21. B φFB,O (first torque command) and the torque command (second torque command) output by the autobalance controller 10B. B φ FB is output as a command relating to the torque to be generated by the actuator of the joint included in the leg 31.

[0068] In this embodiment, the relationship between the torque commands output by the controllers is expressed as in equation (45).

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[0069] [7-2. Vertical Controller] As shown in FIG. 5, the vertical direction controller 13 outputs a torque command indicating the amount of torque that the actuator of the joint should generate in order to bring the substantially vertical position (i.e., height) of the body 34 of the legged robot 30B closer to a predetermined neutral state. B φ FB,C The vertical direction controller 13 can also be said to be a controller that controls the positional relationship between the trunk 34 and the soles of the feet 33 in the approximately vertical direction to be a predetermined positional relationship.

[0070] The vertical direction controller 13 outputs the torque command calculated by the equation (46). B φ FB,C Output.

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[0071] The legged robot 30B according to this embodiment can maintain balance more reliably than the legged robot 30A according to the first embodiment by performing horizontal control, center of pressure control, and vertical control simultaneously.

[0072] 8. Third Example [8-1. Overall composition] Fig. 6 shows a legged robot 30C according to a third embodiment of the present invention. The legged robot 30C includes a trunk (not shown in Fig. 6), two legs 31L and 31R connected to the trunk, and a hybrid controller 20C that controls the legs 31L and 31R. The hybrid controller 20C may be integrated into the trunk or may be provided at a location separate from the trunk.

[0073] The left leg 31L includes a foot 33L having a sole that can apply torque in contact with the ground 50, a leg 32L, and at least one joint. At least one load cell is provided on the sole of the foot 33L to measure torque applied to the foot 33L from the ground 50. In addition, an actuator is provided at each joint.

[0074] The right leg 31R includes a foot 33R having a sole that can apply torque in contact with the ground 50, a leg 32R, and at least one joint. At least one load cell is provided on the sole of the foot 33R to measure torque applied to the foot 33R from the ground 50. In addition, each joint is provided with an actuator.

[0075] Hybrid controller 20C includes a leg controller 21L for controlling left leg 31L and a leg controller 21R for controlling right leg 31R, and an auto-balance controller 10C for automatically maintaining balance. Also, auto-balance controller 10C includes a horizontal direction controller 11L, a center of pressure controller 12L, and a vertical direction controller 13L for controlling left leg 31L, a horizontal direction controller 11R, a center of pressure controller 12R, and a vertical direction controller 13R for controlling right leg 31R, and an external force component extraction matrix calculation unit 14 and external force component extraction units 15, 16, 17 related to the control of both legs 31L, 31R.

[0076] The leg controller 21L outputs a torque command in response to force information sent from the left leg operating device 40L operated by the operator. B φ FLB,O The leg controller 21L also outputs the angle vector q of the joint included in the left leg 31L. FL The position information according to the torque command is fed back to the left leg operating device 40L. B φ FLB,O is the "first torque command" for the left leg 31L.

[0077] The leg controller 21R outputs a torque command in response to force information sent from the right leg operating device 40R operated by the operator. B φFRB,O The leg controller 21R also outputs the angle vector q of the joints included in the right leg 31R. FR The position information according to the torque command is fed back to the right leg operating device 40R. B φ FRB,O is the "first torque command" for the right leg 31R.

[0078] The horizontal direction controller 11L calculates the angle vector q of the joints included in the left leg 31L. FL Torque command obtained from B φ FLB,A Torque command is output. B φ FLB,A is the "third torque command" for the left leg 31L.

[0079] The horizontal direction controller 11R calculates the angle vector q of the joint included in the right leg 31R. FR Torque command obtained from B φ FRB,A Torque command is output. B φ FRB,A is the "third torque command" for the right leg 31R.

[0080] The center of pressure controller 12L calculates the angle vector q of the joints included in the left leg 31L. FL and a ground reaction torque vector n related to the reaction force applied by the ground 50 to the foot 33L. FLG Torque command obtained from B φ FLB,B Torque command is output. B φ FLB,B is the "fourth torque command" for the left leg 31L.

[0081] The center of pressure controller 12R calculates the angle vector q of the joints included in the right leg 31R. FR and a ground reaction torque vector n related to the reaction force applied by the ground 50 to the foot 33R. FRG Torque command obtained from B φ FRB,B Torque command is output. B φ FRB,B is the "fourth torque command" for the right leg 31R.

[0082] The vertical direction controller 13L controls the angle vector q of the joint included in the left leg 31L. FL Torque command obtained from B φ FLB,C Torque command is output. B φ FLB,C is the "fifth torque command" for the left leg 31L.

[0083] The vertical direction controller 13R calculates the angle vector q of the joint included in the right leg 31R. FR Torque command obtained from B φ FRB,C Torque command is output. B φ FRB,C is the "fifth torque command" for the right leg 31R.

[0084] The external force component extraction matrix calculation unit 14 calculates the angle vector q of the joints included in both legs 31L and 31R. FL ,q FR from the external force component extraction matrix Φ ex The force component extraction matrix calculation unit 14 performs this calculation using equation (24). Note that the matrix Π in equation (24) is defined in equation (19). Also, the matrix B Pi FkB is defined by equation (17). The external force component extraction matrix calculation unit 14 calculates the position vector B r FkB Let q be the angle vector FL ,q FR The decision is based on:

[0085] The external force component extraction unit 15 extracts the external force component extraction matrix Φ calculated by the external force component extraction matrix calculation unit 14. ex The torque command output by the horizontal direction controllers 11L and 11R is calculated using the B φ FLB,A , B φ FRB,A The external force component extraction unit 15 performs this extraction using equation (23).

[0086] The external force component extraction unit 16 extracts the external force component extraction matrix Φ calculated by the external force component extraction matrix calculation unit 14. exThe torque command output by the pressure center controllers 12L and 12R is calculated using the B φ FLB,B , B φ FRB,B The external force component extraction unit 16 performs this extraction using equation (23).

[0087] Similarly, the external force component extraction unit 17 extracts the external force component extraction matrix Φ ex Using the torque command output by the vertical direction controllers 13L and 13R, B φ FLB,C , B φ FRB,C The external force component extraction unit 17 performs this extraction using equation (23).

[0088] The autobalance controller 10C receives a torque command B φ FLB,A , torque command B φ FLB,B and torque command B φ FLB,C The torque command is a "second torque command" for the left leg 31L.

[0089] In addition, the autobalance controller 10C is configured to B φ FRB,A , torque command B φ FRB,B and torque command B φ FRB,C The torque command is a "second torque command" for the right leg 31R.

[0090] The hybrid controller 20C controls the torque command output by the leg controller 21L. B φ FLB,O (first torque command) and the torque command (second torque command) for the left leg 31L output by the autobalance controller 10C. B φ FLBis output as a command regarding the torque to be generated by the actuator of the joint included in the left leg 31L.

[0091] In addition, the hybrid controller 20C controls the torque command output from the leg controller 21R. B φ FRB,O (first torque command) and the torque command (second torque command) for the right leg 31R output by the autobalance controller 10C. B φ FRB is output as a command regarding the torque to be generated by the actuator of the joint included in the right leg 31R.

[0092] In this embodiment, the relationship between the torque commands output by the controllers is expressed as in equation (47).

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[0093] According to the legged robot 30C of this embodiment, balance can be maintained more reliably than ever before by performing horizontal control, center of pressure control, and vertical control simultaneously in parallel.

[0094] Furthermore, in the legged robot 30C according to this embodiment, the outputs of the controllers 11L, 11R, 12L, 12R, 13L, and 13R included in the autobalancing controller 10C are not used directly, but rather external force components of the outputs are used. Therefore, the legged robot 30C can avoid a situation in which the left leg 31L and the right leg 31R compress or pull the torso 34 from two directions. This contributes to reducing the load on the actuators that form the joints of the left leg 31L and the right leg 31R and reducing the power consumption of these actuators, and also prevents the control outputs of different legs from interfering with each other and causing a breakdown.

[0095] 9. Fourth Example [9-1. Overall composition] 7 shows a legged robot 30D according to a fourth embodiment of the present invention. The legged robot 30D differs from the legged robot 30C in that the legged robot 30D is equipped with a hybrid controller 20D instead of the hybrid controller 20C, but is otherwise the same as the legged robot 30C.

[0096] Hybrid controller 20D differs from hybrid controller 20C in that it includes autobalance controller 10D instead of autobalance controller 10C, but is common in other respects with hybrid controller 20C. Also, autobalance controller 10D differs from autobalance controller 10C in that it further includes ground contact controller 18L for controlling left leg 31L, ground contact controller 18R for controlling right leg 31R, and internal force component extraction unit 19, but is common in other respects with autobalance controller 10C.

[0097] The ground contact controller 18L calculates the angle vector q of the joints included in the left leg 31L. FL and a ground reaction torque vector n related to the reaction force applied by the ground 50 to the foot 33L. FLG Torque command obtained from B φ FLB,D Torque command is output. B φ FLB,Dis the "sixth torque command" for the left leg 31L. B φ FLB,D The output of the .

[0098] The ground contact controller 18R calculates the angle vector q of the joints included in the left leg 31R. FR and a ground reaction torque vector n related to the reaction force applied by the ground 50 to the foot 33R. FRG Torque command obtained from B φ FRB,D Torque command is output. B φ FRB,D is the "sixth torque command" for the left leg 31R. B φ FRB,D The output of the .

[0099] The internal force component extraction unit 19 extracts the external force component extraction matrix Φ ex Using the torque command output by the grounding controllers 18L and 18R, B φ FLB,D , B φ FRB,D The internal force component extracting unit 19 performs this extraction using equation (26).

[0100] The autobalance controller 10D receives the torque command B φ FLB,A , torque command B φ FLB,B and torque command B φ FLB,C External force components and torque command B φ FLB,D The torque command is a "second torque command" for the left leg 31L.

[0101] The autobalance controller 10D also determines the torque command B φ FRB,A , torque command B φ FRB,B and torque command B φFRB,C External force components and torque command B φ FRB,D The torque command is a "second torque command" for the right leg 31R.

[0102] The hybrid controller 20D controls the torque command output by the leg controller 21L. B φ FLB,O (first torque command) and the torque command (second torque command) for the left leg 31L output by the autobalance controller 10D. B φ FLB is output as a command regarding the torque to be generated by the actuator of the joint included in the left leg 31L.

[0103] In addition, the hybrid controller 20D controls the torque command output from the leg controller 21R. B φ FRB,O (first torque command) and the torque command (second torque command) for the right leg 31R output by the autobalance controller 10D. B φ FRB is output as a command regarding the torque to be generated by the actuator of the joint included in the right leg 31R.

[0104] In this embodiment, the relationship between the torque commands output by the controllers can be expressed as in equation (48).

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[0105] [9-2. Grounding Controller] As shown in FIG. 8, the ground contact controllers 18L, 18R output torque commands indicating the torque amounts that the actuators of the joints should generate to prevent the foot 33L or the foot 33R from lifting off the ground 50 under the influence of center of pressure control when both the left leg 31L and the right leg 31R are on the ground. B φ FLB,D , B φ FRB,D The ground contact controllers 18L, 18R can also be said to be controllers for keeping the soles of the feet 33L, 33R in contact with the ground 50.

[0106] The ground contact controller 18L calculates the floor reaction torque vector obtained from a load cell attached to the sole of the foot 33L. F n FLG Using this, the incomplete integration expressed by equation (49) is performed.

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[0107] The ground controller 18L is F n FLGI,D The torque command calculated by equation (50) using B φ FLB,D Output.

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[0108] The ground controller 18R receives the torque command obtained in the same manner. B φ FRB,D Output.

[0109] Torque command output by pressure center controllers 12L and 12R B φ FLB,B , B φ FRB,B Similarly, torque command B φ FLB,D , B φ FRB,D is said to be limited by an imperfect integrator.

[0110] The legged robot 30D of this embodiment can maintain balance more reliably than the legged robot 30C of the third embodiment by performing horizontal control, center of pressure control, vertical control, and ground contact control simultaneously.

[0111] Furthermore, the legged robot 30C according to this embodiment does not use the outputs of the ground contact controllers 18L, 18R as they are, but uses the internal force components of the outputs. Therefore, the legged robot 30D can keep the feet 33L, 33R in contact with the ground without moving the trunk 34.

[0112] [10. Modifications] Although the first to fourth embodiments of the legged robot according to the present invention have been described above, the configuration of the present invention is not limited to these.

[0113] For example, the horizontal direction controllers 11, 11L, and 11R receive torque commands indicating the amount of torque that the actuators of the joints should generate in order to position the body 34 substantially vertically above the soles of the feet 33, 33L, and 33R. B φ FB,A may be calculated using equation (51).

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[0114] The vertical direction controllers 13, 13L, and 13R also output torque commands indicating the torque amounts that the actuators of the joints should generate in order to bring the displacements of the joints included in the legs 31, 31L, and 31R closer to a predetermined neutral state. B φ FB,C Such a torque command may be output. B φ FB,C can be calculated using equation (52).

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[0115] Furthermore, the horizontal direction controllers 11, 11L, 11R and the vertical direction controllers 13, 13L, 13R can be formally combined into one controller, for example, as in equation (53), by setting an appropriate controller.

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[0116] The imperfect integrators used in the center of pressure controllers 12, 12L, 12R and the grounding controllers 18L, 18R may be imperfect integrators with limiters. Unlike the output limitation of imperfect integrators that depends on the input, this limiter explicitly limits the output.

[0117] Furthermore, the legged robot 30C according to the third embodiment may omit some or all of the external force component extraction units 15, 16, and 17. When all of these are omitted, the external force component extraction matrix calculation unit 14 can also be omitted.

[0118] Similarly, the legged robot 30D according to the fourth example may omit some or all of the external force component extraction units 15, 16, 17 and the internal force component extraction unit 19. When all of these are omitted, the external force component extraction matrix calculation unit 14 can also be omitted.

[0119] Furthermore, the legged robot 30C according to the third embodiment may omit the vertical direction controllers 13L and 13R, in which case the external force component extractor 17 can naturally also be omitted.

[0120] In addition, the feet 33, 33L, and 33R in each embodiment may be provided with a floor reaction force detection sensor other than a load cell. For example, by placing a multi-axis force sensor in the feet, the required floor reaction force can be measured.

[0121] Furthermore, the legged robot according to the present invention may have three or more identical or different legs. [Explanation of symbols]

[0122] 10A, 10B, 10C, 10D Autobalance Controller 11, 11L, 11R Horizontal direction controller 12, 12L, 12R Pressure Center Controller 13, 13L, 13R Vertical direction controller 14 External force component extraction matrix calculation unit 15 External force component extraction section 16 External force component extraction part 17 External force component extraction section 18L, 18R Earth controller 19 Internal force component extraction part 20A, 20B, 20C, 20D Hybrid Controller 21, 21L, 21R Leg controller 30A, 30B, 30C, 30D Legged robot 31 legs 31L left leg 31R right leg 32,32L,32R Legs 33,33L,33R Foot 34 Torso 40 Leg control device 40L left leg control device 40R Right leg control device

Claims

1. A legged robot comprising a trunk, legs connected to the trunk, and a hybrid controller for controlling the legs, The legs are a foot portion having a sole capable of contacting the ground; The legs and At least one joint Including, The hybrid controller includes: an autobalance controller that outputs a first torque command related to automatic balance maintenance; a leg controller that outputs a second torque command based on an arbitrary control; Including, a torque command indicating a sum of torque amounts indicated by the first torque command and the second torque command is output as a command related to a torque to be generated by an actuator of the joint; The autobalance controller includes: a horizontal direction controller that outputs a third torque command; a pressure center controller that outputs a fourth torque command; Including, a torque command indicating a sum of torque amounts indicated by the third torque command and the fourth torque command is output as the first torque command, the third torque command is a command related to a torque to be generated by the actuator of the joint so that the trunk is positioned substantially vertically above the sole of the foot, the fourth torque command is a command related to a torque to be generated by the actuator of the joint so that the center of pressure of a floor reaction force that the sole receives from the ground is at a predetermined position within the sole, The torque amount indicated by the fourth torque command is limited so as not to increase without limit. A legged robot characterized by:

2. The autobalance controller includes: A vertical controller that outputs a fifth torque command further comprising a torque command indicating a sum of torque amounts indicated by the third torque command, the fourth torque command, and the fifth torque command is output as the first torque command; The fifth torque command is a command regarding a torque that the actuator of the joint should generate so that the position of the trunk in the approximately vertical direction approaches a predetermined neutral state, or a command regarding a torque that the actuator of the joint should generate so that the displacement of the joint approaches a predetermined neutral state.

2. The legged robot according to claim 1.

3. The pressure center controller limits the torque amount indicated by the fourth torque command by using an imperfect integrator.

3. The legged robot according to claim 1 or 2.

4. The imperfect integrator is an imperfect integrator with a limiter, in which a limit is imposed on the output.

4. The legged robot according to claim 3.

5. A legged robot comprising a trunk, a plurality of legs connected to the trunk, and a hybrid controller that controls the plurality of legs, Each of the plurality of legs comprises: a foot portion having a sole capable of contacting the ground; The legs and At least one joint Including, The hybrid controller includes: an autobalance controller that outputs a first torque command for each leg related to automatic balance maintenance; a leg controller that outputs a second torque command based on an arbitrary control for each of the legs; Including, a torque command indicating a sum of the torque amounts indicated by the first torque command and the second torque command for the same leg is output as a command regarding the torque to be generated by the actuator of the joint included in the leg; The autobalance controller includes: a horizontal direction controller that outputs a third torque command for each leg; a center of pressure controller that outputs a fourth torque command for each of the legs; Including, a torque command indicating a sum of torque amounts indicated by the third torque command and the fourth torque command for the same leg is output as the first torque command for the leg; the third torque command is a command related to a torque to be generated by the actuator of the joint so that the trunk is positioned substantially vertically above the sole of the foot, the fourth torque command is a command related to a torque to be generated by the actuator of the joint so that the center of pressure of a floor reaction force that the sole receives from the ground is at a predetermined position within the sole, The torque amount indicated by the fourth torque command is limited so as not to increase without limit. A legged robot characterized by:

6. The autobalance controller includes: a vertical direction controller that outputs a fifth torque command for each of the legs; further comprising a torque command indicating a sum of torque amounts indicated by the third torque command, the fourth torque command, and the fifth torque command for the same leg is output as the first torque command for the leg; The fifth torque command is a command regarding a torque that the actuator of the joint should generate so that the position of the trunk in the approximately vertical direction approaches a predetermined neutral state, or a command regarding a torque that the actuator of the joint should generate so that the displacement of the joint approaches a predetermined neutral state.

6. The legged robot according to claim 5.

7. The autobalance controller includes: an external force component extracting unit that extracts external force components of the third torque command, the fourth torque command, and the fifth torque command; further comprising a torque command indicating a sum of torque amounts indicated by the external force component of the third torque command, the external force component of the fourth torque command, and the external force component of the fifth torque command for the same leg is output as the first torque command for the leg.

7. The legged robot according to claim 6.

8. The autobalance controller includes: a ground contact controller that outputs a sixth torque command for each of the legs; an internal force component extraction unit that extracts an internal force component of the sixth torque command; further comprising a torque command indicating a sum of torque amounts indicated by the external force component of the third torque command, the external force component of the fourth torque command, the external force component of the fifth torque command, and the internal force component of the sixth torque command for the same leg is output as the first torque command for the leg, The sixth torque command is a command regarding the torque that the actuator of the joint should generate in order to keep the sole of the foot in contact with the ground.

8. The legged robot according to claim 7.

9. The pressure center controller limits the torque amount indicated by the fourth torque command by using an imperfect integrator. The legged robot according to any one of claims 5 to 8.

10. The imperfect integrator is an imperfect integrator with a limiter, in which a limit is imposed on the output.

10. The legged robot according to claim 9.

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