Legged robot

Abstract

A legged robot according to the present invention comprises 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: an independent-type horizontal direction controller 11a that outputs a third torque command related to torque to be generated by a joint of a leg 31 so that a trunk is located substantially vertically above a sole; and a hip-type pressure center controller 12a that outputs a fourth torque command related to torque to be generated by the joint of the leg 31 so that a pressure center point of a floor reaction force which the sole receives from the ground 50 is located at a predetermined position in the sole, the fourth torque command being determined on the basis of a hip strategy. The automatic balance controller 10A outputs, as the first torque command, a torque command indicating the sum of the torque amounts indicated by the third torque command and the fourth torque command. The present invention provides a legged robot in which balance is maintained more reliably than in conventional legged robots.

Description

legged robot

[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.

[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 an 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 based on the operator's judgment, which is necessary when walking on uneven terrain such as construction sites or disaster sites.

[0004] As such, a remote-controlled legged robot is preferably 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 disclosed 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 maintained by the autobalance controller.

[0005] 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.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.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.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.

[0006] Patent No. 5268107

[0007] However, the autobalance 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.

[0009] In order to achieve the above object, a first legged robot according to the present invention is a robot comprising a trunk, legs connected to the trunk, and a hybrid controller for controlling the legs, wherein the legs include feet having soles that can come into contact with the ground, the legs, and at least one joint, the hybrid controller includes an autobalance controller that outputs a first torque command related to automatic balance maintenance, 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 amount indicated by the first torque command and the torque amount indicated by the second torque command as a command related to the torque to be generated by an actuator of the joint, and the autobalance controller is an independent hydrodynamic controller that outputs a third torque command. The device includes a horizontal direction controller and a hip-type pressure center controller that outputs a fourth torque command, and is configured to output a torque command that indicates the sum of the torque amount indicated by the third torque command and the torque amount indicated by the fourth torque command as a first torque command, the third torque command being a command regarding the torque that the actuator of the joint should generate so that the torso is located approximately vertically above the sole of the foot, the fourth torque command being 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 located at a predetermined position within the sole of the foot, as determined based on the hip strategy, and the torque amount 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 an ankle-type center of pressure controller that outputs a fourth torque command, and may be configured to output, as a first torque command, a torque command that indicates the sum of the torque amount indicated by the third torque command and the torque amount indicated by the fourth torque command output by the hip-type center of pressure controller or the ankle-type center of pressure controller. The fourth torque command output by the ankle-type center of pressure controller is a command related to the torque that should be generated by the actuator of the joint so that the center of pressure of the floor reaction force that the sole receives from the ground is located at a predetermined position within the sole, as determined based on the ankle strategy, and the torque amount indicated by the fourth torque command output by the ankle-type center of pressure controller is limited so that it does not become infinitely large.

[0011] 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 a first torque command, a torque command that indicates the sum of the torque amount indicated by the third torque command, the torque amount indicated by the fourth torque command output by the hip-type center of pressure controller or the ankle-type center of pressure controller, and the torque amount indicated by 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.

[0012] The hip-type center of pressure controller and the ankle-type center of pressure controller of the first legged robot can limit the torque amount indicated by the fourth torque command by using an imperfect integrator, for example.

[0013] In order to achieve the above object, 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 for controlling the plurality of legs, each of the plurality of legs including a foot having a sole capable of contacting the ground, a leg, and at least one joint, the hybrid controller including an autobalance controller for outputting a first torque command for automatic balance maintenance for each leg, and a leg controller for outputting a second torque command based on arbitrary control for each leg, and is configured to output a torque command indicating the sum of a torque amount indicated by the first torque command for a leg and a torque amount indicated by the second torque command for that leg as a command related to a torque to be generated by an actuator of a joint included in that leg, the autobalance controller including a composite horizontal direction controller for outputting a third torque command for each leg, and a hip center of pressure controller for outputting a fourth torque command for each leg, The system is configured to output a torque command indicating the sum of the torque amount indicated by the torque command and the torque amount indicated by a fourth torque command for the leg in question as a first torque command for the leg in question; when the number of legs that are supporting legs is one, the third torque command is a command related to the torque that the actuator of the joint should generate so that the torso is located approximately vertically above the sole of the one leg, and when the number of legs that are supporting legs is two or more, the third torque command is a command related to the torque that the actuator of the joint should generate so that the torso is located approximately vertically above a polygon formed by connecting the soles of the two or more legs; the fourth torque command is a command related to the torque that the actuator of the joint should generate so that the center of pressure of the floor reaction force that the sole receives from the ground is located at a predetermined position within the sole, which is determined based on the hip strategy; and the torque amount indicated by the fourth torque command is limited so that it does not become infinitely large.

[0014] The autobalancing controller of the second legged robot may include an ankle-type center of pressure controller, which serves as an alternative to the hip-type center of pressure controller, and outputs a fourth torque command for each leg. The fourth torque command output by the ankle-type center of pressure controller is a command related to the torque that should be generated by the actuator of the joint so that the center of pressure of the floor reaction force that the sole receives from the ground is located at a predetermined position within the sole, as determined based on the ankle strategy.

[0015] The autobalancing controller of the second legged robot may further include an ankle-type center of pressure controller that outputs a fourth torque command for each leg, and may be configured to output, as a first torque command for that leg, a torque command that indicates the sum of the torque amount indicated by the third torque command for that leg and the torque amount indicated by the fourth torque command output by the hip-type center of pressure controller or the ankle-type center of pressure controller for that leg. The fourth torque command output by the ankle-type center of pressure controller is a command related to the torque that should be generated by the actuator of the joint so that the center of pressure of the floor reaction force that the sole receives from the ground is located at a predetermined position within the sole, as determined based on the ankle strategy.

[0016] 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, as a first torque command for the leg, a torque command that indicates the sum of the torque amount indicated by the third torque command for the leg, the torque amount indicated by the fourth torque command output by the hip-type center of pressure controller or the ankle-type center of pressure controller for the leg, and the torque amount indicated by the fifth torque command for the leg. 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.

[0017] The autobalancing controller of the second legged robot may further include an external force component extraction unit that extracts external force components of the third torque command, fourth torque command, and fifth torque command, and may be configured to output, as the first torque command for the leg, a torque command that indicates the sum of the torque amount indicated by the external force component of the third torque command for the leg, the torque amount indicated by the external force component of the fourth torque command output by the hip-type pressure center controller or the ankle-type pressure center controller for the leg, and the torque amount indicated by the external force component of the fifth torque command for the leg.

[0018] 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 amount indicated by the external force component of the third torque command for the leg, the torque amount indicated by the external force component of the fourth torque command output by the hip-type center of pressure controller or the ankle-type center of pressure controller for that leg, the torque amount indicated by the external force component of the fifth torque command, and the torque amount indicated by the internal force component of the sixth torque command. The sixth torque command is a command related to the torque that should be generated by the actuator of the joint so that the sole of the foot continues to contact the ground.

[0019] The hip-type center of pressure controller and the ankle-type center of pressure controller of the second legged robot can limit the torque amount indicated by the fourth torque command by using an imperfect integrator, for example.

[0020] The autobalancing controller for the second legged robot may further include a determiner that determines whether each of the plurality of legs is a supporting leg or a swing leg.

[0021] The determiner of the second legged robot can, for example, determine that a leg has switched from a supporting leg to a swinging leg when the floor reaction force for the leg continues to be below a predetermined first threshold for a predetermined time or more, and can determine that a leg has switched from a swinging leg to a supporting leg when the floor reaction force for the leg continues to be above a predetermined second threshold for a predetermined time or more.

[0022] According to the present invention, it is possible to provide a legged robot that maintains balance more reliably than conventional robots.

[0023] FIG. 1 is a control block diagram of a legged robot according to a first embodiment of the present invention. FIG. 2 is a schematic diagram for explaining independent horizontal direction control of the present invention. FIG. 3 is a schematic diagram for explaining hip-type center of pressure control of the present invention. FIG. 4 is a control block diagram of a legged robot according to a second embodiment of the present invention. FIG. 5 is a schematic diagram for explaining ankle-type center of pressure control of the present invention. FIG. 6 is a control block diagram of a legged robot according to a third embodiment of the present invention. FIG. 7 is a schematic diagram for explaining vertical direction control of the present invention. FIG. 8 is a control block diagram of a legged robot according to a fourth embodiment of the present invention. FIG. 9 is a schematic diagram for explaining combined horizontal direction control of the present invention. FIG. 10 is a control block diagram of a legged robot according to a fifth embodiment of the present invention. FIG. 11 is a control block diagram of a legged robot according to a sixth embodiment of the present invention. FIG. 12 is a control block diagram of a legged robot according to a seventh embodiment of the present invention. FIG. 13 is a schematic diagram for explaining ground contact control of the present invention. FIG. 14 is a schematic diagram for explaining external force components and internal force components.

[0024] First, various definitions and terms used in this specification will be explained.

[0025] [1. Various definitions] In this specification, an m×n zero matrix is ​​defined as O ｍ×ｎ , n-dimensional zero vector ｎ , n × n identity matrix I ｎ A 3×3 skew-symmetric matrix that satisfies equation (1) for an arbitrary three-dimensional vector x is represented as [a×].

[0026] In this specification, the function ROT(q, p) is defined as in equation (2). The function ROT(q, p) is a rotation vector that rotates vector p to vector q. In other words, when vector p is rotated around the direction of vector ROT(q, p) by an angle equivalent to the magnitude of vector ROT(q, p), the direction of vector p coincides with the direction of vector q.

[0027] In this specification, the generalized saturation function gsat is defined as shown in equation (3). The function gsat returns the value of x saturated to the interval [a, b].

[0028] [2. Inexact Integration] Inexact integration is an operation expressed by equation (4) or equation (5). Here, β is a positive constant called the time constant. The time function y is obtained by imperfectly integrating the time function u with the time constant β. If β = ∞, the operation expressed by Equation (4) or (5) becomes a perfect integral. Imperfect integration can be considered a mathematical extension of normal integration (perfect integration). On a time scale sufficiently shorter than the time constant β, the time function y takes a value close to the integral value of the time function u. However, unlike a perfect integral, the time function y does not grow without bound, even if the time function u maintains a constant non-zero value for a long period of time. Therefore, for example, by using the imperfect integral of Equation (4) or (5) as a substitute for integration in PI control (proportional-integral control), the PI control input can be prevented from growing without bound, even when a steady-state error exists.

[0029] As will be described 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.

[0030] 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 at 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 (kε{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 be simply expressed as a foot coordinate system F.

[0031] In this specification, a 3×3 posture matrix indicating the posture of the foot coordinate system F as viewed 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 Ｂr ＦＢ (6), the generalized velocity vector of the foot seen from the body coordinate system B Ｂ v ＦＢ is expressed as in equation (7). Generalized Velocity Vector Ｂ v ＦＢ is a six-dimensional vector in which a three-dimensional translational velocity vector and a three-dimensional angular velocity vector are arranged vertically.

[0032] In this specification, for example, if a leg includes m joints, the angle vector q of the m joints is Ｆ is expressed as in equation (8). Generalized Velocity Vector Ｂ v ＦＢ and angle vector q Ｆ The relational expression (9) holds between Ｂ J ＦＢ is the appropriate Jacobian matrix expressed in equation (10).

[0033] [4. Statics] In this specification, for example, if a leg includes m joints, the torque vector τ of the m joints is Ｆ is expressed as Equation (11), and the generalized force vector applied by the leg to the foot expressed in the body coordinate system B is Ｂ φ ＦＢ is expressed as in equation (12). Generalized Force Vector Ｂ φ ＦＢ is a six-dimensional vector in which a three-dimensional translational velocity vector and a three-dimensional torque vector are arranged vertically.

[0034] 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 as mentioned above.

[0035] The generalized force vector applied to the body by the leg (leg part) expressed in the body coordinate system B is Ｂ φ ＢＦ Then, the generalized force vectorＢ φ ＢＦ and the generalized force vector Ｂ φ ＦＢ The relation (14) holds between Here, the matrix Ｂ Pi ＦＢ is defined as in equation (15).

[0036] [5. External Force Components and Internal Force Components] [5-1. Definitions] In this specification, when a legged robot has n legs connected to its trunk that are 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 that can apply a generalized force equivalent to the distance norm to the trunk." Furthermore, in this specification, the distance norm is defined as "the vector sequence with the smallest norm based on the distance criterion that each leg applies to the trunk [ 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."

[0037] [5-2. Generalized forces generated by legs and generalized forces applied to the trunk] Generalized force vectors applied by the legs to the feet expressed in trunk coordinate system B Ｂ φ Ｆ１Ｂ , ..., Ｂ φ ＦｎＢ, and the generalized force vectors that each leg exerts on the trunk expressed in the trunk coordinate system B. Ｂ φ Ｂ１Ｌ , ..., Ｂ φ ＢｎＲ As explained using equation (14), the relational expression (16) holds between them. Here, the matrix Ｂ Pi ＦkＢ is defined as in equation (17).

[0038] 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). However, the matrices and vectors in the above equations are defined as in equations (19) and (20).

[0039] [5-3. Extraction of external and internal force components] The generalized force vector sequence [ Ｂ φ Ｆ１Ｂ Ｔ , ..., Ｂ φ ＦｎＢ Ｔ ] Ｔ As explained using equation (18), is the generalized resultant force vector expressed by equation (21). Ｂ φ ＢＧ Add to the body.

[0040] 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 obtain an 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 will be referred to as φ ｅｘ This is equivalent to finding (where . When p≧6n, the analytical solution of the above equation is given by equation (23). where the matrix Φ ｅｘ is defined as shown in equation (24). Furthermore, the matrix P is a 6n×6n matrix, and its definition is as shown in equation (25). Here, the matrix V is Ｔ V is a 6n×(6−p) full-rank matrix where V is a zero matrix. Ｔ is assumed to be full rank, but those skilled in the art can easily construct equations for cases where this is not the case.

[0041] 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.

[0042] In this specification, the external force component extraction matrix Φ ｅｘ Using φ to external force component φ ｅｘ or the internal force component φ ｉｎ The 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). Ψ ｅｘ is a function that extracts the external force component of the vector of the second argument when the coefficient κ is 1, and Ψ ｉｎ is a function that extracts the internal force component of the second argument vector when the coefficient κ is 1. When the coefficient κ is 0, the function Ψ ｅｘoutputs the second argument vector as is, and Ψ ｉｎ will be 0.

[0043] 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 (kε{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 in equation (29). The matrix U is suitably determined, for example, by taking into consideration the rated torque of the actuator of each joint. For example, when the number of actuators m in each leg is 6 or more and the actuator of each joint outputs a torque equal to the rated torque, the generalized force vector sequence φ ＊ Index related to the size of ||Uφ ＊ To make ∥ equal to 1, the matrix U can be set as shown in equation (30). Here, D ｋ is an m × m diagonal matrix in which the rated torque values ​​of m actuators of the kth leg are arranged on a diagonal line. When the number of joints in each leg is 6 or more (i.e., m≧6), the external force component extraction matrix Φ is calculated using this matrix U and equation (24). ｅｘ can be obtained.

[0044] [5-4. Simple Extraction Example 1] The concept of extracting external and internal force components is easier to understand if we simplify a legged robot with a trunk and two legs (left and right legs) as shown in Figure 14. In Figure 14, there is a mass point corresponding to the trunk in one-dimensional space, and actuators corresponding to the left and right legs are attached to the left and right of this. In this extraction example, it is assumed that the rated outputs of the left and right actuators are the same.

[0045] The force applied by the left leg actuator to the torso is f Ｌ , the force applied by the right leg actuator to 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]. In addition, in this case, the generalized force vector sequence [f Ｌ , f Ｒ ] Ｔ The size of the Ｌ ２ +f Ｒ ２ ), the matrix U is expressed as in equation (31).

[0046] From these facts, the external force component extraction matrix Φ ｅｘ is calculated as shown in equation (32). Therefore, the generalized force vector sequence [f Ｌ , f Ｒ ] Ｔ The external force component (i.e., f Ｌ External force component f Ｌ，ｅｘ and f Ｒ External force component f Ｒ，ｅｘ ), and internal force components (i.e., f Ｌ Internal force component f Ｌ，ｉｎ and f Ｒ External force component f Ｒ，ｉｎ ) can be extracted using equations (33) and (34).

[0047] 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]. 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 [fＬ，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 from the left and right with the same force, and does not contribute to the movement of the trunk.

[0048] [5-5. Simple Extraction Example 2] In this extraction example, the rated output of the left leg actuator is assumed to be twice the rated output of the right leg actuator. In this case, the generalized force vector sequence [f Ｌ , f Ｒ ] Ｔ The size of √((f Ｌ / 2) ２ +f Ｒ ２ ) and then, the matrix U and the external force component extraction matrix Φ ｅｘ are expressed as equations (35) and (36). Therefore, the external force component (f Ｌ，ｅｘ , f Ｒ，ｅｘ ) and internal force component (f Ｌ，ｉｎ , f Ｒ，ｉｎ ) can be extracted using equations (37) and (38).

[0049] For example, the force command value for each leg is [f Ｌ = 4N, f Ｒ = 2N], the external force component is [f Ｌ，ｅｘ = 4.8 N, f Ｒ，ｅｘ = 1.2N] and the internal force component is [f Ｌ，ｉｎ = -0.8N, f Ｒ，ｉｎ = 0.8N]. The force command value for each leg is [f Ｌ = 4N, f Ｒ = -2N], the external force component is [f Ｌ，ｅｘ = 1.6 N, f Ｒ，ｅｘ = 0.4N], and the internal force component is [f Ｌ，ｉｎ = 2.4 N, f Ｒ，ｉｎ=-2.4 N]. The external force component can be said to be the force command value for each leg, averaged while 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.

[0050] Next, first to seventh embodiments of the legged robot according to the present invention will be described with reference to the accompanying drawings.

[0051] [6. First embodiment] [6-1. Overall configuration] 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.

[0052] 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. Furthermore, an actuator is provided at each joint.

[0053] The hybrid controller 20A includes a leg controller 21 that outputs torque commands in response to commands from the operator, and an autobalance controller 10A that outputs torque commands related to automatic balance maintenance. The autobalance controller 10A further includes an independent horizontal direction controller 11a and a hip-type center of pressure controller 12a. An example of the leg controller 21 is a force-projecting bilateral controller proposed by the inventor of the present application in Japanese Patent Application No. 2014-093322, etc.

[0054] The leg controller 21 outputs a torque command in response to force information sent from a leg operating device 40 operated by an operator. Ｂ φ ＦＢ，Ｏ In other words, the leg controller 21 outputs a torque command based on an arbitrary control. Ｂ φ ＦＢ，ＯThe leg controller 21 also outputs the angle vector q of the joint included in the leg 31. Ｆ The 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. Ｂ φ ＦＢ，Ｏ corresponds to the "first torque command" of the present invention.

[0055] The independent horizontal direction controller 11a is configured to calculate the angle vector q of the joint included in the leg 31. Ｆ Torque command calculated 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 .

[0056] The hip-type center of pressure controller 12a calculates the angle vector q of the joint 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 calculated 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 .

[0057] The autobalance controller 10A receives a torque command Ｂ φ ＦＢ，Ａ and torque command Ｂ φ ＦＢ，Ｂ This torque command corresponds to the "second torque command" of the present invention.

[0058] The hybrid controller 20A controls the torque command output from the leg controller 21. Ｂ φ ＦＢ，Ｏ a torque command indicating the sum of the torque amounts indicated by the torque command (first torque command) output by the autobalance controller 10A 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.

[0059] In this embodiment, the relationship between the torque commands output by the controllers can be expressed as in equation (39).

[0060] [6-2. Independent Horizontal Direction Controller] As shown in FIG. 2, the independent horizontal direction controller 11a outputs torque commands indicating the amount of torque that the actuators of the joints should generate in order to position the body 34 of the legged robot 30A substantially vertically above the soles of the feet 33. Ｂ φ ＦＢ，Ａ The independent horizontal direction controller 11a 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 a predetermined positional relationship.

[0061] The independent horizontal direction controller 11a uses the torque command calculated by the equation (40). Ｂ φ ＦＢ，Ａ Output. where: Ｂ R Ｆ is a posture matrix that indicates the posture of the foot coordinate system F as viewed from the body coordinate system B, as described above. Ｆ n ＢＦ，Ａ is a torque vector that the foot 33 should apply to the body 34, expressed in the foot coordinate system F. Note that the posture matrix Ｂ R Ｆ is the angle vector q of the joint included in the leg 31 Ｆ The determination can be made based on the following:

[0062] Torque Vector Ｆ n ＢＦ，Ａ can be expressed as in equation (41). Here, K Ａ is the properly set proportional gain, and B Ａis the appropriately set derivative gain, and Ｆ r ＢＦ is the position vector of the body 34 as seen from the foot coordinate system F. Ｆ r ＢＦ is the angle vector q of the joint included in the leg 31 Ｆ It can be determined based on the following: Ｆ z is the vertical unit vector expressed in the foot coordinate system, i.e., Ｆ z = (R Ｆ ) Ｔ [0, 0, 1] Ｔ = ( Ｂ R Ｆ ) Ｔ (R Ｂ ) Ｔ [0, 0, 1] Ｔ Here, the orientation matrix Ｂ R Ｆ is the angle vector q of the joint included in the leg 31 Ｆ and the orientation matrix R Ｂ can be obtained if an inertial measurement unit (IMU) is attached to the fuselage 34. Ｂ If it is not possible to find the xy plane of the foot coordinate system, we assume that it is approximately a horizontal plane. Ｆ z = [0, 0, 1] Ｔ It may also be possible to use the following.

[0063] [6-3. Hip-type center of pressure controller] As shown in FIG. 3, the hip-type center of pressure controller 12a controls the torque command 12b, which indicates the amount of torque that the actuator of each joint should generate in order to keep the center of pressure (the so-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.

[0064] The hip-type center of pressure controller 12a 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 Then, the incomplete integration expressed by the equation (42) is performed using Here, K ＩＢ is the properly set integral gain, and KＰＢ is the appropriately set proportional gain, and β Ｂ is a properly set time constant. Ｆ n ＦＧＩ，Ｂ is the floor reaction torque vector Ｆ n ＦＧ For example, if the body 34 is continuously pushed by a constant external force, the floor reaction torque vector Ｆ n ＦＧ Even if maintains a constant non-zero value for a long period of time, Ｆ n ＦＧＩ，Ｂ does not grow without limit.

[0065] The hip-type center of pressure controller 12a 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 hip strategy. Ｆ φ ＦＢ，Ｂ is determined as shown in equation (43). When the leg 32 applies the torque amount of the above formula to the foot 33, the torque amount that the leg 32 applies to the torso 34 expressed in the foot coordinate system F can be expressed as in formula (44). where: Ｆ r ＦＢ is a representation of the position vector of the foot 33 as seen from the body 34 in the foot coordinate system F.

[0066] Torque command output by the hip-type pressure center controller 12a Ｂ φ ＦＢ，Ｂ is the torque command of equation (43). Ｆ φ ＦＢ，Ｂ is expressed in the body coordinate system B. Torque command Ｂ φ ＦＢ，Ｂ can be calculated by equation (45). Torque Command Ｂ φ ＦＢ，Ｂ is said to be limited by an imperfect integrator. Ｂ R Ｆ is the angle vector q of the joint included in the leg 31 Ｆ The determination can be made based on the following:

[0067] For example, if the foot 33 has a toe and a heel, the torso 34 and the leg 32 are connected via a hip joint, and an external force applied to the torso 34 causes the ZMP to be continuously shifted from a predetermined position in the sole toward the toe, the hip-type center of pressure controller 12a generates in the leg 31 (particularly the hip joint actuator) a torque that tilts the torso 34 forward (toward the toe) and a torque that thrusts the hip joint backward (toward the heel). This brings the ZMP closer to the predetermined position in the sole.

[0068] According to the legged robot 30A of this embodiment, the horizontal direction control and the center of pressure control are performed simultaneously in parallel, thereby making it possible to maintain balance more reliably than conventional methods.

[0069] 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 it is equipped with a hybrid controller 20B instead of the hybrid controller 20A, but is otherwise the same as the legged robot 30A.

[0070] 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 an ankle-type center of pressure controller 12b, but is common to autobalance controller 10A in other respects (particularly, the inclusion of independent-type horizontal direction controller 11a and hip-type center of pressure controller 12a).

[0071] The ankle-type center of pressure controller 12b calculates the angle vector q of the joint 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 calculated from Ｂ φ ＦＢ，Ｂ Torque command is output. Ｂ φ ＦＢ，ＢThis corresponds to the "fourth torque command" of the present invention. Ｂ φ ＦＢ，Ｂ The output of the .

[0072] The autobalance controller 10B controls the torque command output from the independent horizontal direction controller 11a. Ｂ φ ＦＢ，Ａ and the torque command output from the hip-type pressure center controller 12a or the ankle-type pressure center controller 12b. Ｂ φ ＦＢ，Ｂ This torque command corresponds to the "second torque command" of the present invention.

[0073] The hybrid controller 20B controls the torque command output from the leg controller 21. Ｂ φ ＦＢ，Ｏ a torque command indicating the sum of the torque amounts indicated by the torque command (first torque command) output by the autobalance controller 10B 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.

[0074] In this embodiment, the relationship between the torque commands output by the controllers can be summarized as in the above-mentioned equation (39).

[0075] [7-2. Ankle-type center of pressure controller] As shown in FIG. 5, the ankle-type center of pressure controller 12b controls the torque command 12b, which indicates the amount of torque that the actuator of each joint should generate in order to keep the center of pressure ZMP (CoP) of the floor reaction force that the sole of the foot 33 receives from the ground 50 at a predetermined position within the sole. Ｂ φ ＦＢ，Ｂ Output.

[0076] The ankle-type pressure center controller 12b, like the hip-type pressure center controller 12a, 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 Then, the incomplete integration expressed by the equation (42) is performed using

[0077] The ankle-type pressure center controller 12b 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 (46). Torque command output by the anchor type pressure center controller 12b Ｂ φ ＦＢ，Ｂ This torque command Ｆ φ ＦＢ，Ｂ is expressed in the body coordinate system B. Torque command Ｂ φ ＦＢ，Ｂ can be calculated by equation (47). Torque Command Ｂ φ ＦＢ，Ｂ is said to be limited by an imperfect integrator. Ｂ R Ｆ is the angle vector q of the joint included in the leg 31 Ｆ The determination can be made based on the following:

[0078] 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 of the foot toward the toe side due to an external force applied to the trunk 34, the ankle-type center of pressure controller 12b generates a torque in the leg 31 (particularly the actuator of the ankle joint) that tilts the trunk 34 backward (toward the heel). As a result, the ZMP approaches the predetermined position in the sole of the foot.

[0079] The legged robot 30B according to this embodiment includes a hip-type center of pressure controller 12a based on a hip strategy and an ankle-type center of pressure controller 12b based on an ankle strategy. Therefore, the legged robot 30B according to this embodiment can maintain balance more reliably and appropriately than the legged robot 30A according to the first embodiment by selectively using the two types of center of pressure control depending on the situation. The center of pressure control based on the hip strategy is particularly effective when it is necessary to recover a posture that has been significantly disrupted by a large external force or when it is necessary to maintain the soles of the feet on the ground. The center of pressure control based on the ankle strategy is particularly effective when it is necessary to prevent large displacement of the torso (for example, when the torso is carrying a fragile object). The center of pressure control based on the ankle strategy also has the advantage of being less susceptible to interference with control by other controllers.

[0080] 6 shows a legged robot 30C according to a third embodiment of the present invention. Legged robot 30C differs from legged robot 30B in that it is equipped with hybrid controller 20C instead of hybrid controller 20B, but is otherwise the same as legged robot 30B.

[0081] Hybrid controller 20C differs from hybrid controller 20B in that it includes autobalance controller 10C instead of autobalance controller 10B, but is common to hybrid controller 20B in other respects. Autobalance controller 10C also differs from autobalance controller 10B in that it further includes vertical direction controller 13, but is common to autobalance controller 10B in other respects (particularly, the inclusion of independent horizontal direction controller 11a, hip-type center of pressure controller 12a, and ankle-type center of pressure controller 12b).

[0082] The vertical direction controller 13 calculates the angle vector q of the joint included in the leg 31. Ｆ Torque command calculated from Ｂ φ ＦＢ，Ｃ Torque command is output. Ｂ φ ＦＢ，ＣThis corresponds to the "fifth torque command" of the present invention. Ｂ φ ＦＢ，Ｃ The output of the .

[0083] The autobalance controller 10C controls the torque command output from the independent horizontal direction controller 11a. Ｂ φ ＦＢ，Ａ and the torque command output from the hip-type pressure center controller 12a or the ankle-type pressure center controller 12b. Ｂ φ ＦＢ，Ｂ and the torque command output by the vertical direction controller 13. Ｂ φ ＦＢ，Ｃ The torque command representing the sum of the torque amounts represented by the torques ...

[0084] The hybrid controller 20C controls the torque command output from the leg controller 21. Ｂ φ ＦＢ，Ｏ a torque command indicating the sum of the torque amounts indicated by the torque command (first torque command) output by the autobalance controller 10C and the torque command (second torque command) output by the autobalance controller 10C; 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.

[0085] In this embodiment, the relationship between the torque commands output by the controllers is expressed as in equation (48).

[0086] [8-2. Vertical Direction Controller] As shown in FIG. 7, the vertical direction controller 13 outputs a torque command indicating the amount of torque that the actuators of the joints should generate in order to bring the substantially vertical position (i.e., height) of the body 34 of the legged robot 30C closer to a predetermined neutral state. Ｂ φ ＦＢ，Ｃ The vertical direction controller 13 can also be said to be a controller for controlling the positional relationship between the trunk 34 and the soles of the feet 33 in the substantially vertical direction to a predetermined positional relationship.

[0087] The vertical direction controller 13 outputs the torque command calculated by the equation (49). Ｂ φ ＦＢ，Ｃ Output. Here, K Ｃ is the properly set proportional gain, and B Ｃ is an appropriately set differential gain. ｄ is the target height corresponding to the predetermined neutral state of the fuselage 34, Ｂ r ＦＢ，ｄ is the position vector of the foot seen from the body coordinate system B Ｂ r ＦＢ is the target value for Ｂ z is the vertical unit vector expressed in the body coordinate system, i.e., Ｂ z = (R Ｂ ) Ｔ [0, 0, 1] Ｔ This orientation matrix R Ｂ can be obtained if an inertial measurement unit (IMU) is attached to the fuselage 34. Ｂ If it is not possible to find the xy plane of the foot coordinate system, we assume that it is approximately a horizontal plane. Ｂ z= Ｂ R Ｆ [0, 0, 1] Ｔ Orientation matrix Ｂ R Ｆ is the angle vector q of the joint included in the leg 31 Ｆ The "predetermined neutral state" can be determined based on the above formula. The "predetermined neutral state" may be a single target height value, a range of values, or a set of multiple values. To achieve a neutral state for a range of values, for example, the first term of the first component on the right side of equation (49) can be replaced with another formula using a dead-band function. Those skilled in the art can easily construct such a formula. Furthermore, those skilled in the art can easily replace the first term of the first component on the right side of equation (49) with a formula that achieves a neutral state for multiple values.

[0088] According to the legged robot 30C of this embodiment, the horizontal control, center of pressure control, and vertical control are performed simultaneously in parallel, allowing the robot to maintain balance more reliably than the legged robot 30B of the second embodiment.

[0089] 9. Fourth Embodiment 9-1. Overall Configuration Figure 8 shows a legged robot 30D according to a fourth embodiment of the present invention. The legged robot 30D includes a trunk (not shown in Figure 8), two legs 31L, 31R connected to the trunk, and a hybrid controller 20D that controls the legs 31L, 31R. The hybrid controller 20D may be integrated into the trunk, or may be provided at a location separate from the trunk.

[0090] 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 that measures torque applied to the foot 33L from the ground 50 is provided on the sole of the foot 33L. Furthermore, an actuator is provided at each joint.

[0091] 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 that measures torque applied to the foot 33R from the ground 50 is provided on the sole of the foot 33R. Furthermore, an actuator is provided at each joint.

[0092] The hybrid controller 20D includes a leg controller 21L for controlling the left leg 31L and a leg controller 21R for controlling the right leg 31R, as well as an auto-balance controller 10D for automatically maintaining balance. The auto-balance controller 10D also includes a combined horizontal direction controller 11bL, a hip type center of pressure controller 12aL, and a vertical direction controller 13L for controlling the left leg 31L, a combined horizontal direction controller 11bR, a hip type center of pressure controller 12aR, and a vertical direction controller 13R for controlling the right leg 31R, 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, and a determiner (not shown).

[0093] 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.

[0094] 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 φ ＦＲＢ，Ｏ The leg controller 21R also outputs the angle vector q of the joint 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.

[0095] The composite horizontal direction controller 11bL is configured to calculate the angle vector q of the joint included in the left leg 31L. ＦＬ and the angle vector q of the joint included in the right leg 31R ＦＲ Torque command calculated from Ｂ φ ＦＬＢ，Ａ Torque command is output. Ｂ φ ＦＬＢ，Ａ is a "third torque command" for the left leg 31L. Ｂ φ ＦＬＢ，Ａ The output of the .

[0096] The composite horizontal direction controller 11bR is configured to calculate the angle vector q of the joint included in the right leg 31R. ＦＲ and the angle vector q of the joint included in the left leg 31L ＦＬ Torque command calculated from Ｂ φ ＦＲＢ，Ａ Torque command is output. Ｂ φ ＦＲＢ，Ａ is a "third torque command" for the right leg 31R. Ｂ φ ＦＲＢ，Ａ The output of the .

[0097] The hip-type center of pressure controller 12aL calculates the angle vector q of the joint included in the left leg 31L. ＦＬand a floor reaction torque vector n related to the reaction force applied by the ground 50 to the foot 33L. ＦＬＧ Torque command calculated from Ｂ φ ＦＬＢ，Ｂ Torque command is output. Ｂ φ ＦＬＢ，Ｂ is the "fourth torque command" for the left leg 31L.

[0098] The hip-type center of pressure controller 12aR is configured to calculate the angle vector q of the joint included in the right leg 31R. ＦＲ and a floor reaction torque vector n related to the reaction force applied by the ground 50 to the foot 33R. ＦＲＧ Torque command calculated from Ｂ φ ＦＲＢ，Ｂ Torque command is output. Ｂ φ ＦＲＢ，Ｂ is the "fourth torque command" for the right leg 31R.

[0099] The vertical direction controller 13L calculates the angle vector q of the joint included in the left leg 31L. ＦＬ Torque command calculated from Ｂ φ ＦＬＢ，Ｃ Torque command is output. Ｂ φ ＦＬＢ，Ｃ is the "fifth torque command" for the left leg 31L.

[0100] The vertical direction controller 13R calculates the angle vector q of the joint included in the right leg 31R. ＦＲ Torque command calculated from Ｂ φ ＦＲＢ，Ｃ Torque command is output. Ｂ φ ＦＲＢ，Ｃ is the "fifth torque command" for the right leg 31R.

[0101] 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 external 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 the formula (17). The external force component extraction matrix calculation unit 14 calculates the position vector Ｂ rＦｋＢ angle vector q ＦＬ , q ＦＲ The decision is based on:

[0102] 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 commands output by the composite horizontal direction controllers 11bL and 11bR are calculated using the Ｂ φ ＦＬＢ，Ａ , Ｂ φ ＦＲＢ，Ａ The external force component extraction unit 15 performs this extraction using equation (23).

[0103] 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. ｅｘ The torque command output by the hip-type pressure center controllers 12aL and 12aR 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).

[0104] Similarly, the external force component extraction unit 17 extracts the external force component extraction matrix Φ calculated by the external force component extraction matrix calculation unit 14. ｅｘ The torque commands output by the vertical direction controllers 13L and 13R are calculated using the Ｂ φ ＦＬＢ，Ｃ , Ｂ φ ＦＲＢ，Ｃ The external force component extracting unit 17 performs this extraction using equation (23).

[0105] The determiner calculates the floor reaction torque vector obtained from the load cells attached to the foot 33L of the left leg 31L and the foot 33R of the right leg 31R. Ｆ n ＦＬＧ , Ｆ n ＦＲＧ Specifically, the determiner determines whether each of the left leg 31L and the right leg 31R is a supporting leg or a free leg by using the floor reaction torque vector of the left leg 31L. Ｆ n ＦＬＧ continues to be below a preset first threshold value for a predetermined time, it is determined that the left leg 31L has switched from the supporting leg to the free leg, and the floor reaction torque vector of the left leg 31L Ｆ nＦＬＧ When the first threshold value and the second threshold value continue to exceed a predetermined time, the left leg 31L is determined to have switched from a free leg to a supporting leg. The determiner performs a similar determination for the right leg 31R. Each controller constituting the autobalance controller 10D can refer to the result of the determination by the determiner. The first threshold value and the second threshold value may be the same value or different values.

[0106] The autobalance controller 10D 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.

[0107] The autobalance controller 10D also receives a torque command 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.

[0108] The hybrid controller 20D controls the torque command output by the leg controller 21L. Ｂ φ ＦＬＢ，Ｏ a torque command indicating the sum of the torque amounts indicated by the torque command (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.

[0109] The hybrid controller 20D also controls the torque command output by the leg controller 21R. Ｂ φ ＦＲＢ，Ｏ a torque command indicating the sum of the torque amounts indicated by the torque command (first torque command) and the torque command (second torque command) for the right leg 31R output by the autobalance controller 10D; Ｂ φ ＦＲＢis output as a command regarding the torque to be generated by the actuator of the joint included in the right leg 31R.

[0110] In this embodiment, the relationship between the torque commands output by the controllers is expressed as in equation (50). Here, κ is a coefficient that is 1 when both the left leg 31L and the right leg 31R are supporting legs, and is 0 when only the left leg 31L or only the right leg 31R is a supporting leg. In this embodiment, as shown in Table 1, the combined horizontal direction controllers 11bL, 11bR, hip-type center of pressure controllers 12aL, 12aR, and vertical direction controllers 13L, 13R are enabled / disabled depending on the coefficient κ and whether the left leg 31L or the right leg 31R is a supporting leg or a free leg. Disabled controllers output torque commands that indicate zero. For example, when only the left leg 31L is the supporting leg, the combined horizontal direction controller 11bL is enabled and the combined horizontal direction controller 11bR is disabled. When both the left leg 31L and the right leg 31R are supporting legs, the combined horizontal direction controllers 11bL and 11bR are enabled.

[0111] [9-2. Combined Horizontal Direction Controller] When the left leg 31L is the supporting leg and the other leg (right leg 31R) is the free leg, the combined horizontal direction controller 11bL outputs a torque command indicating the amount of torque that should be generated by the actuator of each joint of the left leg 31L so that the trunk 34 is located approximately vertically above the sole of the foot 33L. Ｂ φ ＦＬＢ，Ａ When the left leg 31L and the other leg (right leg 31R) are supporting legs, the composite horizontal direction controller 11bL outputs a torque command ≠ ... Ｂ φ ＦＬＢ，ＡThe composite horizontal direction controller 11bL can be said to be a controller for controlling the positional relationship between the torso 34 and the feet 33L (and the feet 33R) in the approximately horizontal direction to a predetermined positional relationship. Note that A is a constant set to be equal to or greater than 0 and less than 0.5. The constant A is preferably about 0.1.

[0112] When the left leg 31L is the supporting leg and the other leg (right leg 31R) is the free leg, the composite horizontal direction controller 11bL calculates a target value for the position vector Ｆ r ＢＦ，ｄ is defined as in equation (51).

[0113] On the other hand, when the left leg 31L and the other leg (right leg 31R) are the supporting legs, the composite horizontal direction controller 11bL sets the target value for the position vector Ｆ r ＢＦ，ｄ is defined as in equation (52). Here, x is a vector expressed as in equation (53). In the horizontal direction control by the composite horizontal direction controller 11bL, the subscript F indicates the left leg 31L, and the subscript F ０ indicates the other leg (right leg 31R). Ｆ r Ｆ０Ｆ is the position vector of the foot 33R of the other leg (right leg 31R) as viewed from the left foot coordinate system FL. Ｆ r Ｆ０Ｆ is the angle vector q of the joints included in the left leg 31L and the right leg 31R. ＦＬ , q ＦＲ The determination can be made based on the following:

[0114] When the left leg 31L is the supporting leg and the other leg (right leg 31R) is the free leg, the composite horizontal direction controller 11bL outputs the torque command calculated by the equations (51), (54), and (55). Ｂ φ ＦＢ，Ａ ( Ｂ φ ＦＬＢ，Ａ On the other hand, when the left leg 31L and the other leg (right leg 31R) are the supporting legs, the composite horizontal direction controller 11bL outputs the torque command calculated by the equations (52), (53), (54), and (55). Ｂ φ ＦＢ，Ａ (Ｂ φ ＦＬＢ，Ａ ) is output. Here, K Ａ is the properly set proportional gain, and B Ａ is the appropriately set derivative gain. Ｆ r ＢＦ is the left foot coordinate system F Ｌ is the position vector of the fuselage 34 as seen from Ｂ R Ｆ is the left foot coordinate system F seen from the body coordinate system B. Ｌ is the orientation matrix that indicates the orientation of Ｆ n ＢＦ，Ａ is the left foot coordinate system F Ｌ is the torque vector that the foot 33L should apply to the body 34, expressed as the position vector Ｆ r ＢＦ is the angle vector q of the joint included in the left leg 31L ＦＬ The determination can be made based on the following:

[0115] The composite horizontal direction controller 11bR uses the torque command obtained in the same manner. Ｂ φ ＦＲＢ，Ａ In the horizontal direction control by the composite horizontal direction controller 11bR, the subscript F indicates the right leg 31R, and the subscript F ０ indicates the other leg (left leg 31L).

[0116] According to the legged robot 30D of this embodiment, the horizontal direction control, the center of pressure control, and the vertical direction control are performed simultaneously in parallel, thereby making it possible to maintain balance more reliably than ever before.

[0117] Furthermore, the legged robot 30D according to this embodiment does not directly use the outputs of the controllers 11bL, 11bR, 12aL, 12aR, 13L, and 13R included in the autobalancing controller 10D, but rather uses external force components of these outputs. Therefore, the legged robot 30D 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.

[0118] 10 shows a legged robot 30E according to a fifth embodiment of the present invention. Legged robot 30E differs from legged robot 30D in that it is equipped with hybrid controller 20E instead of hybrid controller 20D, but is otherwise the same as legged robot 30D.

[0119] Hybrid controller 20E differs from hybrid controller 20D in that hybrid controller 20E includes autobalance controller 10E instead of autobalance controller 10D, but is common to hybrid controller 20D in other respects. Also, autobalance controller 10E differs from autobalance controller 10D in that it includes ankle-type center of pressure controllers 12bL, 12bR instead of hip-type center of pressure controllers 12aL, 12aR, but is common to autobalance controller 10D in other respects (particularly, the inclusion of combined-type horizontal direction controllers 11bL, 11bR, vertical direction controllers 13L, 13R, external force component extraction matrix calculation unit 14, and external force component extraction units 15, 16, 17).

[0120] The autobalance controller 10E 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.

[0121] The autobalance controller 10E also receives a torque command 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.

[0122] The hybrid controller 20E controls the torque command output by the leg controller 21L. Ｂ φ ＦＬＢ，Ｏ a torque command indicating the sum of the torque amounts indicated by the torque command (first torque command) and the torque command (second torque command) for the left leg 31L output by the autobalance controller 10E; 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.

[0123] The hybrid controller 20E also controls the torque command output by the leg controller 21R. Ｂ φ ＦＲＢ，Ｏ a torque command indicating the sum of the torque amounts indicated by the torque command (first torque command) and the torque command (second torque command) for the right leg 31R output by the autobalance controller 10E; 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.

[0124] In this embodiment, the relationship between the torque commands output by the controllers can be summarized as in the above-mentioned equation (50).

[0125] 11 shows a legged robot 30F according to a sixth embodiment of the present invention. Legged robot 30F differs from legged robot 30D in that it is equipped with hybrid controller 20F instead of hybrid controller 20D, but is otherwise the same as legged robot 30D.

[0126] Hybrid controller 20F differs from hybrid controller 20D in that it includes autobalance controller 10F instead of autobalance controller 10D, but is common to hybrid controller 20D in other respects. Also, autobalance controller 10F differs from autobalance controller 10D in that it further includes ankle-type center of pressure controllers 12bL, 12bR, but is common to autobalance controller 10D in other respects (particularly, the inclusion of combined-type horizontal direction controllers 11bL, 11bR, hip-type center of pressure controllers 12aL, 12aR, vertical direction controllers 13L, 13R, external force component extraction matrix calculation unit 14, and external force component extraction units 15, 16, 17).

[0127] The autobalance controller 10F receives the torque command output from the composite horizontal direction controller 11bL. Ｂ φ ＦＬＢ，Ａ and the torque command output by the hip-type pressure center controller 12aL or the ankle-type pressure center controller 12bL. Ｂ φ ＦＬＢ，Ｂ and the torque command output by the vertical direction controller 13L. Ｂ φ ＦＬＢ，Ｃ The torque command representing the sum of the torque amount represented by the external force component of the left leg 31L and the torque amount represented by the external force component of the left leg 31L is output. This torque command is a "second torque command" for the left leg 31L.

[0128] The auto-balance controller 10F also controls the torque command output from the composite horizontal direction controller 11bR. Ｂ φ ＦＲＢ，Ａ and the torque command output by the hip-type pressure center controller 12aR or the ankle-type pressure center controller 12bR. Ｂ φ ＦＲＢ，Ｂ and the torque command output by the vertical direction controller 13R. Ｂ φ ＦＲＢ，Ｃ This torque command is a "second torque command" for the right leg 31R.

[0129] The hybrid controller 20F controls the torque command output by the leg controller 21L. Ｂ φ ＦＬＢ，Ｏa torque command indicating the sum of the torque amounts indicated by the torque command (first torque command) and the torque command (second torque command) for the left leg 31L output by the autobalance controller 10F; 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.

[0130] The hybrid controller 20F also controls the torque command output from the leg controller 21R. Ｂ φ ＦＲＢ，Ｏ a torque command indicating the sum of the torque amounts indicated by the torque command (first torque command) and the torque command (second torque command) for the right leg 31R output by the autobalance controller 10F; 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.

[0131] In this embodiment, the relationship between the torque commands output by the controllers can be summarized as in the above-mentioned equation (50).

[0132] 12 shows a legged robot 30G according to a seventh embodiment of the present invention. Legged robot 30G differs from legged robot 30F in that it is equipped with hybrid controller 20G instead of hybrid controller 20F, but is otherwise the same as legged robot 30F.

[0133] Hybrid controller 20G differs from hybrid controller 20F in that it includes autobalance controller 10G instead of autobalance controller 10F, but is common to hybrid controller 20F in other respects. Also, autobalance controller 10G differs from autobalance controller 10F 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 to autobalance controller 10F in other respects.

[0134] The ground contact controller 18L calculates the angle vector q of the joint included in the left leg 31L. ＦＬ and a floor reaction torque vector n related to the reaction force applied by the ground 50 to the foot 33L.ＦＬＧ Torque command calculated from Ｂ φ ＦＬＢ，Ｄ Torque command is output. Ｂ φ ＦＬＢ，Ｄ is a "sixth torque command" for the left leg 31L. Ｂ φ ＦＬＢ，Ｄ The output of the .

[0135] The ground contact controller 18R calculates the angle vector q of the joint included in the left leg 31R. ＦＲ and a floor reaction torque vector n related to the reaction force applied by the ground 50 to the foot 33R. ＦＲＧ Torque command calculated 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 .

[0136] The internal force component extraction unit 19 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 grounding controllers 18L and 18R is calculated using the Ｂ φ ＦＬＢ，Ｄ , Ｂ φ ＦＲＢ，Ｄ The internal force component extracting unit 19 performs this extraction using equation (26).

[0137] The autobalance controller 10G receives the torque command output from the composite horizontal direction controller 11bL. Ｂ φ ＦＬＢ，Ａ and the torque command output by the hip-type pressure center controller 12aL or the ankle-type pressure center controller 12bL. Ｂ φ ＦＬＢ，Ｂ and the torque command output by the vertical direction controller 13L. Ｂ φ ＦＬＢ，Ｃ and the torque command output by the ground contact controller 18L. Ｂ φ ＦＬＢ，Ｄand the torque amount indicated by the internal force component of the left leg 31L. This torque command is a "second torque command" for the left leg 31L.

[0138] The autobalance controller 10G also controls the torque command output from the composite horizontal direction controller 11bR. Ｂ φ ＦＲＢ，Ａ and the torque command output by the hip-type pressure center controller 12aR or the ankle-type pressure center controller 12bR. Ｂ φ ＦＲＢ，Ｂ and the torque command output by the vertical direction controller 13R. Ｂ φ ＦＲＢ，Ｃ and the torque command output by the ground contact controller 18R. Ｂ φ ＦＲＢ，Ｄ This torque command is a "second torque command" for the right leg 31R.

[0139] The hybrid controller 20G controls the torque command output by the leg controller 21L. Ｂ φ ＦＬＢ，Ｏ a torque command indicating the sum of the torque amounts indicated by the torque command (first torque command) and the torque command (second torque command) for the left leg 31L output by the autobalance controller 10G; 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.

[0140] The hybrid controller 20G also controls the torque command output from the leg controller 21R. Ｂ φ ＦＲＢ，Ｏ a torque command indicating the sum of the torque amounts indicated by the torque command (first torque command) and the torque command (second torque command) for the right leg 31R output by the autobalance controller 10G; 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.

[0141] In this embodiment, the relationship between the torque commands output by the controllers can be expressed as in equation (56). Here, as described above, κ is a coefficient that is 1 when both the left leg 31L and the right leg 31R are supporting legs, and is 0 when only the left leg 31L or only the right leg 31R is a supporting leg. In this embodiment, as shown in Table 2, the combined horizontal direction controllers 11bL, 11bR, hip-type center of pressure controllers 12aL, 12aR, ankle-type center of pressure controllers 12bL, 12bR, vertical direction controllers 13L, 13R, and ground contact controllers 18L, 18R are enabled / disabled depending on the coefficient κ and whether the left leg 31L or the right leg 31R is a supporting leg or a swing leg. Disabled controllers output torque commands that indicate zero.

[0142] [12-2. Ground Contact Controller] As shown in FIG. 13, the ground contact controllers 18L, 18R generate torque commands that indicate the amount of torque that the actuators of the joints should generate to prevent the foot 33L or the foot 33R from lifting off the ground 50 due to the influence of center of pressure control when both the left leg 31L and the right leg 31R are in contact with 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.

[0143] 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 Then, the incomplete integration expressed by the equation (57) is performed using Here, K ＩＤ is the properly set integral gain, and K ＰＤ is the appropriately set proportional gain, and β Ｄ is a properly set time constant. Ｆ n ＦＬＧＩ，Ｄ is the floor reaction torque vector Ｆ n ＦＬＧ For example, if the body 34 is continuously pushed by a constant external force, the floor reaction torque vector Ｆ n ＦＬＧ Even if maintains a constant non-zero value for a long period of time, Ｆ nＦＬＧＩ，Ｂ does not become infinitely large. ＩＤ , proportional gain K ＰＤ and time constant β Ｄ is the K used in the center of pressure control ＩＢ , K. ＰＢ and β Ｂ It may be the same as or different from these.

[0144] The ground controller 18L Ｆ n ＦＬＧＩ，Ｄ The torque command calculated by the equation (58) using Ｂ φ ＦＬＢ，Ｄ Output. In addition, the posture matrix Ｂ R ＦＬ is the angle vector q of the joint included in the left leg 31L ＦＬ The determination can be made based on the following:

[0145] The ground controller 18R receives the torque command obtained in the same manner. Ｂ φ ＦＲＢ，Ｄ Output.

[0146] Torque commands output by the hip-type pressure center controllers 12aL, 12aR and the ankle-type pressure center controllers 12bL, 12bR 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.

[0147] According to the legged robot 30G of this embodiment, the horizontal control, center of pressure control, vertical control, and ground contact control are performed simultaneously in parallel, allowing the robot to maintain balance more reliably than the legged robot 30F of the sixth embodiment.

[0148] Furthermore, the legged robot 30G according to this embodiment does not use the outputs of the ground contact controllers 18L, 18R as they are, but rather uses the internal force components of the outputs, so that the legged robot 30G can keep the feet 33L, 33R in contact with the ground without moving the torso 34.

[0149] [13. Modifications] Although the first to seventh 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.

[0150] For example, the independent horizontal direction controller 11 a may generate torque commands indicating the amount of torque that the actuators of the joints should generate in order to position the torso 34 substantially vertically above the soles of the feet 33 . Ｂ φ ＦＢ，Ａ may be calculated using equation (59). Here, K Ａ is the properly set proportional gain, and B Ａ is the appropriately set derivative gain.

[0151] The independent horizontal direction controller 11a according to equation (59) generates only a translational force on the foot, and does not generate a rotational force (torque). This allows the ankle joint torque assigned to the center of pressure controller to be increased within the range of the "ankle joint torque limit to prevent the sole of the foot from lifting off the ground," which is unavoidable in center of pressure control as an ankle strategy. Furthermore, by reducing the maximum torque required for the ankle joint actuator, the weight of the tip of the foot can be reduced, which is an advantage not available in the implementation according to equation (40).

[0152] Furthermore, the vertical direction controllers 13, 13L, and 13R 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 by equation (60). Here, K Ｃ is the properly set proportional gain, and B Ｃ is the appropriately set differential gain. Ｆ is the joint angle vector, and q Ｆ，ｄ is the angle vector q ＦThe "predetermined neutral state" may be a single target value, a range of target values, or a set of multiple values. When the range of values ​​is set to the neutral state, for example, (q Ｆ，ｄ -q Ｆ ) in equation (60) can be modified to another equation using an appropriate dead band function. It is easy for a person skilled in the art to create such an equation. Ｆ，ｄ -q Ｆ It would be easy for a person skilled in the art to replace the part (60) with an equation in which multiple values ​​are in a neutral state. Furthermore, although the inverse matrix in equation (60) does not exist when the number of joints in the legs 31, 31L, and 31R is not six, a person skilled in the art could easily construct a similar algorithm that can be used in such a case.

[0153] Furthermore, the independent horizontal direction controller 11a and vertical direction controller 13 can be formally combined into one controller, for example, as in equation (61), by setting appropriate controllers. Here, K Ｃ is the properly set proportional gain, and B Ｃ is the appropriately set derivative gain, and Ｂ r ＦＢ，ｄ is the position vector of the foot seen from the body coordinate system B Ｂ r ＦＢ and is a target value representing a predetermined neutral state where the control targets of both the independent horizontal direction controller 11a and the vertical direction controller 13 can be achieved.

[0154] Furthermore, the imperfect integrators used in the hip-type center of pressure controllers 12a, 12aL, 12aR, the ankle-type center of pressure controllers 12b, 12bL, 12bR, and the ground contact controllers 18L, 18R may be imperfect integrators with limiters. Unlike the output limitation of an imperfect integrator that depends on the input, this limiter explicitly sets a limit on the output.

[0155] Furthermore, the legged robot 30D according to the fourth embodiment, the legged robot 30E according to the fifth embodiment, and the legged robot 30F according to the sixth embodiment may omit some or all of the external force component extraction units 15, 16, and 17. If all of these are omitted, the external force component extraction matrix calculation unit 14 can also be omitted.

[0156] Similarly, the legged robot 30G according to the seventh example may omit some or all of the external force component extraction units 15, 16, and 17 and the internal force component extraction unit 19. If all of these are omitted, the external force component extraction matrix calculation unit 14 can also be omitted.

[0157] Furthermore, the legged robot 30D according to the fourth embodiment, the legged robot 30E according to the fifth embodiment, the legged robot 30F according to the sixth embodiment, and the legged robot 30G according to the seventh embodiment may omit the vertical direction controllers 13L and 13R. In this case, it goes without saying that the external force component extractor 17 can also be omitted.

[0158] Furthermore, 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 disposing a multi-axis force sensor in the foot, it is possible to measure the required floor reaction force.

[0159] Furthermore, the legged robot according to the present invention may have three or more identical or different legs.

[0160] When the legs include a first leg, a second leg, a third leg, a fourth leg, ..., an n-th leg, a composite horizontal direction controller that controls each leg generates the following torque command: Ｂ φ Ｆ＊Ｂ，Ａ (1) When the first leg is the supporting leg and all other legs (the second leg, the third leg, the fourth leg, ..., the n-th leg) are free legs: The composite horizontal direction controller that controls the first leg outputs a torque command indicating the amount of torque that the actuator of each joint of the first leg should generate in order to position the trunk approximately vertically above the sole of the first leg. Ｂ φ Ｆ１Ｂ，Ａ(2) When the first and second legs are supporting legs and all other legs (third, fourth, ..., n-th legs) are free legs, the composite horizontal direction controller that controls the first leg outputs a torque command τ that indicates the amount of torque that the actuator of each joint of the first leg should generate in order to position the trunk approximately vertically above the line segment connecting the soles of the first and second legs. Ｂ φ Ｆ１Ｂ，Ａ The compound horizontal direction controller that controls the second leg outputs a torque command that indicates the amount of torque that the actuator of each joint of the second leg should generate in order to position the trunk approximately vertically above the line segment. Ｂ φ Ｆ２Ｂ，Ａ (3) When the first, second, and third legs are supporting legs and all other legs (fourth leg, ..., nth leg) are free legs, the composite horizontal direction controller that controls the first leg outputs a torque command ∑ ∑ a ∑ b ∑ i ∑ t ∑ t ∑ a ∑ b ... a ∑ b ∑ a ∑ b ∑ a ∑ b ∑ a ∑ b ∑ Ｂ φ Ｆ１Ｂ，Ａ The composite horizontal direction controller that controls the second leg outputs a torque command that indicates the amount of torque that the actuator of each joint of the second leg should generate in order to position the trunk approximately vertically above the triangle. Ｂ φ Ｆ２Ｂ，Ａ The composite horizontal direction controller that controls the third leg outputs a torque command τ that indicates the torque amount that the actuator of each joint of the third leg should generate in order to position the trunk approximately vertically above the triangle. Ｂ φ Ｆ３Ｂ，Ａ Output.

[0161] In summary, the composite horizontal direction controller can be said to be a controller that keeps the trunk positioned approximately vertically above the polygon formed by connecting the soles of all supporting legs. The control in (1) above is a control that moves the trunk along a special polygon (= point) with only one vertex, and the control in (2) above is a control that moves the trunk along a special polygon (= line segment) with only two vertices.

[0162] 10A, 10B, 10C, 10D, 10E, 10F, 10G Autobalance controller 11a Independent horizontal direction controller 11bL, 11bR Combined horizontal direction controller 12a, 12aL, 12aR Hip type center of pressure controller 12b, 12bL, 12bR Ankle type center of pressure controller 13, 13L, 13R Vertical direction controller 14 External force component extraction matrix calculation unit 15 External force component extraction unit 16 External force component extraction unit 17 External force component extraction unit 18L, 18R Ground contact controller 19 Internal force component extraction unit 20A, 20B, 20C, 20D, 20E, 20F, 20G Hybrid controller 21, 21L, 21R Leg controller 30A, 30B, 30C, 30D, 30E, 30F, 30G Legged robot 31 Leg 31L Left leg 31R Right leg 32, 32L, 32R Leg section 33, 33L, 33R Foot section 34 Body 40 Leg operation device 40L Left leg operation device 40R Right leg operation device

Claims

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 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 a torque amount indicated by the first torque command and a torque amount indicated by 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: an independent horizontal direction controller that outputs a third torque command; a hip-type center of pressure controller that outputs a fourth torque command; Including, a torque command indicating a sum of a torque amount indicated by the third torque command and a torque amount indicated by 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 command being determined based on a hip strategy; The torque amount indicated by the fourth torque command is limited so as not to increase without limit. A legged robot characterized by: 　 The autobalance controller includes: An ankle-type pressure center controller that outputs a fourth torque command further comprising a torque command indicating a sum of a torque amount indicated by the third torque command and a torque amount indicated by the fourth torque command output by the hip type center of pressure controller or the ankle type center of pressure controller is output as the first torque command, the fourth torque command output by the ankle-type center of pressure controller is a command related to a torque to be generated by the actuator of the joint so that the center of pressure of the floor reaction force that the sole receives from the ground is at a predetermined position within the sole, the command being determined based on an ankle strategy; The torque amount indicated by the fourth torque command output by the anchor-type pressure center controller is limited so as not to increase without limit.

2. The legged robot according to claim 1. 　 The autobalance controller includes: A vertical controller that outputs a fifth torque command further comprising a torque command indicating a sum of a torque amount indicated by the third torque command, a torque amount indicated by the fourth torque command output by the hip type center of pressure controller or the ankle type center of pressure controller, and a torque amount indicated by 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.

3. The legged robot according to claim 2. 　 The hip-type center of pressure controller and the ankle-type center of pressure controller limit the torque amount indicated by the fourth torque command by using an imperfect integrator.

3. The legged robot according to claim 2. 　 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 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 a torque amount indicated by the first torque command for the leg and a torque amount indicated by the second torque command for the leg is output as a command regarding a torque to be generated by an actuator of the joint included in the leg, The autobalance controller includes: a composite horizontal direction controller that outputs a third torque command for each leg; a hip-type center of pressure controller that outputs a fourth torque command for each of the legs; Including, a torque command indicating a sum of a torque amount indicated by the third torque command for the leg and a torque amount indicated by the fourth torque command for the leg is output as the first torque command for the leg; the third torque command is a command regarding a torque that should be generated by the actuator of the joint so that the trunk is located approximately vertically above the sole of the one leg when the number of the legs that are supporting legs is one, and a command regarding a torque that should be generated by the actuator of the joint so that the trunk is located approximately vertically above a polygon formed by connecting the soles of the two or more legs when the number of the legs that are supporting legs is two or more, 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 command being determined based on a hip strategy; The torque amount indicated by the fourth torque command is limited so as not to increase without limit. A legged robot characterized by: 　 The autobalance controller includes: an ankle-type center of pressure controller that outputs a fourth torque command for each of the legs, as an alternative to the hip-type center of pressure controller; Including, The fourth torque command output by the ankle-type center of pressure controller is a command related to the torque that should be generated by the actuator of the joint so that the center of pressure of the floor reaction force that the sole receives from the ground is at a predetermined position within the sole, which is determined based on an ankle strategy.

6. The legged robot according to claim 5. 　 The autobalance controller includes: an ankle-type pressure center controller that outputs a fourth torque command for each of the legs; further comprising a torque command indicating a sum of a torque amount indicated by the third torque command for the leg and a torque amount indicated by the fourth torque command output by the hip-type center of pressure controller or the ankle-type center of pressure controller for the leg, as the first torque command for the leg; The fourth torque command output by the ankle-type center of pressure controller is a command related to the torque that should be generated by the actuator of the joint so that the center of pressure of the floor reaction force that the sole receives from the ground is at a predetermined position within the sole, which is determined based on an ankle strategy.

6. The legged robot according to claim 5. 　 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 a torque amount indicated by the third torque command for the leg, a torque amount indicated by the fourth torque command output by the hip-type center of pressure controller or the ankle-type center of pressure controller for the leg, and a torque amount indicated by the fifth torque command for the 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.

8. The legged robot according to claim 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 the sum of a torque amount indicated by an external force component of the third torque command for the leg, a torque amount indicated by an external force component of the fourth torque command output by the hip-type pressure center controller or the ankle-type pressure center controller for the leg, and a torque amount indicated by an external force component of the fifth torque command for the leg, as the first torque command for the leg.

9. The legged robot according to claim 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 a torque amount indicated by an external force component of the third torque command for the leg, a torque amount indicated by an external force component of the fourth torque command output by the hip type center of pressure controller or the ankle type center of pressure controller for the leg, a torque amount indicated by an external force component of the fifth torque command, and a torque amount indicated by an internal force component of the sixth torque command, 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.

10. The legged robot according to claim 9. 　 The hip-type center of pressure controller and the ankle-type center of pressure controller limit the torque amount indicated by the fourth torque command by using an imperfect integrator.

7. The legged robot according to claim 6. 　 The autobalance controller includes: a determiner for determining whether each of the plurality of legs is a supporting leg or a swing leg; Also includes 6. The legged robot according to claim 5. 　 The determiner determines that the leg has switched from the supporting leg to the free leg when the floor reaction force for the leg continues to be below a predetermined first threshold value for more than a predetermined time, and determines that the leg has switched from the free leg to the supporting leg when the floor reaction force for the leg continues to be above a predetermined second threshold value for more than a predetermined time.

13. The legged robot according to claim 12.

Images