Leg joint assist device for legged movable robot
First Claim
1. A leg joint assist device for a legged mobile robot having legs, each of the legs configured by connecting a plurality of link members from a body via a plurality of joints, comprising:
- a spring means for generating an auxiliary driving force acting on a specific joint among the plurality of the joints with an elastic energy stored in accordance with relative displacement motion between a pair of link members connected by the specific joint, together with a driving force of a joint actuator that drive the specific joint,wherein the spring means is provided so that, during the relative displacement motion between the pair of link members, the auxiliary driving force increases as a relative displacement amount between the pair of link members increases when the relative displacement amount is smaller than or equal to a predetermined displacement amount, and so that the auxiliary driving force becomes smaller than or almost equal to the auxiliary driving force obtained at the predetermined displacement amount after the relative displacement amount exceeds the predetermined displacement amount,wherein the relative displacement motion between the pair of link members comprises bending/stretching motion at the specific joint, and the relative displacement amount comprises a bending angle between the pair of link members, and wherein a value of the bending angle increases as a magnitude of bending of the pair of link members increases, andwherein the predetermined displacement amount is set to an angle smaller than the bending angle between the pair of link members at a largest bending decree in a foot lifted state of each of the legs while the legged mobile robot is moved on an almost flat floor with a certain gait.
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Accused Products
Abstract
An assist device is provided with a spring device that generates an auxiliary driving force, by an elastic energy, acting on a joint of a leg. The spring device includes a gas spring having a cylinder and a piston. Bending/stretching motion between link members and at the joint is transmitted to the spring device through a motion transmission device that includes a link arm. The spring device is provided so that the auxiliary driving force increases as a knee bending angle θ increases until the knee bending angle θ reaches a predetermined angle, and so that, once the knee bending angle θ exceeds the predetermined angle, the auxiliary driving force becomes smaller than or equal to the driving force obtaining at the predetermined angle, effectively reducing a burden on an actuator of the legged mobile robot joint.
24 Citations
13 Claims
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1. A leg joint assist device for a legged mobile robot having legs, each of the legs configured by connecting a plurality of link members from a body via a plurality of joints, comprising:
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a spring means for generating an auxiliary driving force acting on a specific joint among the plurality of the joints with an elastic energy stored in accordance with relative displacement motion between a pair of link members connected by the specific joint, together with a driving force of a joint actuator that drive the specific joint, wherein the spring means is provided so that, during the relative displacement motion between the pair of link members, the auxiliary driving force increases as a relative displacement amount between the pair of link members increases when the relative displacement amount is smaller than or equal to a predetermined displacement amount, and so that the auxiliary driving force becomes smaller than or almost equal to the auxiliary driving force obtained at the predetermined displacement amount after the relative displacement amount exceeds the predetermined displacement amount, wherein the relative displacement motion between the pair of link members comprises bending/stretching motion at the specific joint, and the relative displacement amount comprises a bending angle between the pair of link members, and wherein a value of the bending angle increases as a magnitude of bending of the pair of link members increases, and wherein the predetermined displacement amount is set to an angle smaller than the bending angle between the pair of link members at a largest bending decree in a foot lifted state of each of the legs while the legged mobile robot is moved on an almost flat floor with a certain gait. - View Dependent Claims (2, 3, 4, 5, 6, 7, 10, 11, 12, 13)
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8. A leg joint assist device for a legged mobile robot having legs, each of the legs configured by connecting a plurality of link members from a body via a plurality of joints, comprising:
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a spring means for generating an auxiliary driving force acting on a specific joint among the plurality of the joints with an elastic energy stored in accordance with relative displacement motion between a pair of link members connected by the specific joint, together with a driving force of a joint actuator that drive the specific joint, wherein the spring means is provided so that, during the relative displacement motion between the pair of link members, the auxiliary driving force increases as a relative displacement amount between the pair of link members increases when the relative displacement amount is smaller than or equal to a predetermined displacement amount, and so that the auxiliary driving force becomes smaller than or almost equal to the auxiliary driving force obtained at the predetermined displacement amount after the relative displacement amount exceeds the predetermined displacement amount, wherein the relative displacement motion between the pair of link members comprises bending/stretching motion at the specific joint, and the relative displacement amount comprises a bending angle between the pair of link members, and wherein a value of the bending angle increases as a magnitude of bending of the pair of link members increases, and wherein the spring means is provided so that the auxiliary driving force increases/decreases by linear reciprocating motion of an engagement member engaged with the spring means, the assist device comprises rotary motion to linear motion transforming means for transforming rotary motion of a rotating shaft of the specific joint, the rotary motion generating the bending/stretching motion between the pair of link members, into straight reciprocating motion and transmitting the straight reciprocating motion to the engagement member, and the rotary motion to linear motion transforming means is configured to move the engagement member directionally outwards to increase the auxiliary driving force of the spring means as the bending angle between the pair of link members increases, at least until the bending angle between the pair of link members is increased to an angle equivalent to the predetermined displacement amount, and to move the engagement member directionally inwards to decrease the auxiliary driving force of the spring means, after the bending angle between the pair of link members exceeds the angle equivalent to the predetermined displacement amount.
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9. A leg joint assist device for a legged mobile robot having legs, each of the legs configured by connecting a plurality of link members from a body via a plurality of joints, comprising:
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a spring means for generating an auxiliary driving force acting on a specific joint among the plurality of the joints with an elastic energy stored in accordance with relative displacement motion between a pair of link members connected by the specific joint, together with a driving force of a joint actuator that drive the specific joint, wherein the spring means is provided so that, during the relative displacement motion between the pair of link members, the auxiliary driving force increases as a relative displacement amount between the pair of link members increases when the relative displacement amount is smaller than or equal to a predetermined displacement amount, and so that the auxiliary driving force becomes smaller than or almost equal to the auxiliary driving force obtained at the predetermined displacement amount after the relative displacement amount exceeds the predetermined displacement amount, wherein the relative displacement motion between the pair of link members comprises bending/stretching motion at the specific joint, and the relative displacement amount comprises a bending angle between the pair of link members, and wherein a value of the bending angle increases as a magnitude of bending of the pair of link members increases, wherein the spring means comprises a gas spring comprising;
a cylinder;
a piston disposed within the cylinder so as to be able to slide synchronously with bending/stretching motion between the pair of link members;
a gas chamber formed within the cylinder and having a volume that changes as the piston slides; and
gas filling the gas chamber, wherein the auxiliary driving force is generated elastically by compression or expansion of the gas within the gas chamber accompanied by changes in volume of the gas chamber, andfurther comprising rotary motion to linear motion transforming means, as means for sliding the piston synchronously with the bending/stretching motion between the pair of link members, for transforming rotary motion of a rotating shaft of the specific joint, the rotary motion generating the bending/stretching motion between the pair of link members, into straight reciprocating motion and transmitting the straight reciprocating motion to the piston, wherein the rotary motion to linear motion transforming means is configured to move the piston directionally outwards to increase the auxiliary driving force of the gas spring at least until the bending angle between the pair of link members is increased to an angle equivalent to the predetermined displacement amount, and to move the piston directionally inwards to decrease the auxiliary driving force of the gas spring, after the bending angle between the pair of link members exceeds the angle equivalent to the predetermined displacement amount.
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Specification