CN101898594A - Walking method for dynamic biped robot - Google Patents

Abstract

The invention discloses a walking method for a dynamic biped root and belongs to the technical field of the walking control of robots. The method is characterized by comprising the following steps of: during the walking of the robot, applying a dynamic force to support feet to make the support feet actively finish the extension and contraction actions within a walking period and controlling the extension and contraction positions of the support feet to complement the potential energy of a system. The gait of the walking method is determined by five key frames and described by two angle parameters, wherein the key frames are connected with one another through a continuous smooth curve of a first order derivative. On a prototype, the robot can stably walk at different speeds under the control of the dynamic walking method.

Description

A kind of walking method for dynamic biped robot

Technical field

The present invention is based on a kind of biped power type walking method of passive walking principle, by add power on the robot supporting leg, realizes the open loop travel controls of dynamic biped robot.

Background technology

How to realize that quick, stabilized walking is emphasis and difficult point during the biped robot studies.At present, biped robot's traveling method mainly comprises static walking, ZMP walking, and limit cycle walking.Wherein static walking be occur the earliest also be most basic a kind of traveling method, it requires, and the barycenter of robot remains in the polygon that both feet constitute on the ground in the walking process, this method is easy to keep the stable of robot, but has also limited the speed of travel of robot greatly.The ZMP theory requires the zero moment point of robot to remain in the polygon of both feet formation, this method has reduced artificial constraint than the static state walking to a certain extent, on using, model machine obtained great success, the ASIMO that comprises Honda company, the HRP4 of Japan AIST research institute, and the Qrio of Sony etc.Yet, be difficult to have again breakthrough at aspects such as natural gait and energy efficiencies according to the theoretical design-calculated robot of ZMP.

The limit cycle walking is a kind of new walking theory that occurs in recent years, its proposition has been subjected to the inspiration of human walking, requiring periodic gait sequence is orbitally stable, be that gait sequence can form a stable limit cycle in state space, but any instantaneous local stability that do not have in gait cycle.This method is less to the artificial constraint of robot, has utilized the dynamics of robot self under the gravitational field fully, thereby has energy efficiency, speed and antijamming capability that robot ambulation is improved in bigger space.At present, the successful examples of employing limit cycle walking principle comprises Spring Flamingo and the dummy model control method thereof of MIT, the Rabbit of France academy of sciences and mixing zero dynamic control method thereof, people's such as Geng RunBot and nervous centralis control method thereof, and the biped robot of CMU and encourage learning method etc. again.These robots have been realized bigger breakthrough at aspects such as the speed of travel, energy efficiency and antijamming capabilities, but gait generation method is comparatively loaded down with trivial details, and some then needs to use machine learning, to having relatively high expectations of experimental situation.

Passive walking is a kind of prominent example of limit cycle walking, and robot is walked downwards along little slope of inclining, and does not need to apply any control, and the gravitional force that the slope provides is converted into the required kinetic energy of robot ambulation.The gait that passive walking generates is very natural, and energy efficiency can reach human level, is 1/tens of ZMP walking robot ASIMO approximately.For passive walking is realized on the level land, Cornell university has used the method that increases power at the robot ankle place, lead leg and the ground hind paw that bumps is pedaled ground in per step, and be walking injection energy.Deflt university has then adopted in the way of leading leg with collision on the ground front clamp hip joint, has reached the purpose of mending energy equally.But the energy of above two kinds of methods is mended into all being positioned at collision front and back constantly opportunity, energy is that instantaneous benefit is gone into, requirement has high energy density, therefore limited the speed of travel of robot to a great extent, this energy is mended into method and can be caused bigger disturbance to gait simultaneously, has reduced the stability of walking.

Among the former patent ZL200810116148.6 of this seminar a kind of level land power traveling method has been proposed, it by in walking on one's own initiative elongate support leg and shortening lead leg the potential energy of replenishment system barycenter, realize the energy supplement in the walking and the balance of loss.Power biped robot traveling method of the present invention is based on passive walking principle, initiatively shortens the potential energy that supporting leg comes the replenishment system barycenter again by initiatively extending earlier in a walking is walked.This method is compared with the way in the patent before, eliminated equally and led leg and collision on the ground moment is mended the influence that walking stability is caused into energy, can make robot reach higher walking stability, and it also only needs open loop control, realization is simple and calculated amount is very little, therefore is applicable to the occasion that real-time is had relatively high expectations.In addition, it will be added on the supporting leg in the control sets, and does not need to control leading leg, and has reduced the variable of control, and this control method can make system mend into energy be a fixed value, thereby have the advantage of the progressive balance of energy.

Summary of the invention

The objective of the invention is to from passive walking principle, propose a kind of method and realize the power type walking method of biped robot on the level land at adding power on the supporting leg.

Biped robot's model of the present invention as shown in Figure 1, wherein 1 is the robot health, quality is M, 2 is the supporting leg thigh, 3 is the supporting leg shank, and 4 are equivalent supporting leg (being made of the top of supporting leg thigh 2 line to supporting leg shank 3 ends), and 5 for leading leg thigh, 6 are the shank of leading leg, and 7 are equivalence lead leg (being made of the top of the thigh 5 of the leading leg line to shank 6 ends of leading leg).Robot has three angle θ, α, β, and wherein θ and α are the critical angle of control robot walking, and θ is equivalent supporting leg 4 and equivalent angle of leading leg between 7; α is the angle between supporting leg thigh 2 and the equivalent supporting leg 4, determines the length of equivalent supporting leg 4, α＞0 when the supporting leg knee bends, α when the supporting leg knee stretches=0; β leads leg 5 and lead leg angle between 7 of equivalence, the length that the decision equivalence is led leg, and β when leading leg knee bends＞0, β=0 when the swing knee stretches does not need control in the process of walking owing to lead leg, so β keeps a constant.The angle between the convenient definite two equivalent legs of definition critical angle like this and the length of two equivalent legs.One walking of robot is walked by swing process and collision to form, and wherein swing process refers to that robot supporting leg end lands, and is axially preceding swing with the end, and leading leg simultaneously swings to supporting leg the place ahead by the supporting leg rear aloft; Collision refers to lead leg when swing process finishes terminal and the instantaneous time collision takes place on ground, and supporting leg is liftoff simultaneously.Leading leg after the collision is converted to supporting leg, and supporting leg is converted to leads leg.One walking of robot is walked by beginning after the previous step collision, finishes to collision through swing process.

The energy conversion principle of biped robot's traveling method of the present invention as shown in Figure 2, for the effect of outstanding supporting leg, only at two moments of the whole story in step two legs that draws, middle constantly all having omitted led leg among the figure.Robot is started to walk constantly from A, and this moment equivalent supporting leg and equivalence led leg isometric, and it will be soon liftoff to lead leg, liftoff after, supporting leg freely swings to moment B.Robot in a step swing process by stretching supporting leg knee joint (from moment B to moment C) earlier, bent support leg knee joint (from moment C to moment D) again then, thus reach elongation and shorten the length of equivalent supporting leg 4, come the potential energy of replenishment system.Remain unchanged behind the supporting leg knee joint bending, continue swing forward, two legs bump with a fixing angle and ground, finish the walking of one-period.The process that supporting leg stretches is to mend process into energy to system, and system capacity increases E ₁In order to guarantee that two legs are isometric when colliding, and supporting leg can not ad infinitum extend, so in the walking process in a step, supporting leg is also wanted crooked Hui Yuanchang before bumping with ground, the process of supporting leg bending is the process that system capacity reduces, and system capacity reduces E ₂In order to make robot gross energy increase, i.e. E in the walking process in a step ₁And E ₂Poor E _cGreater than zero, the position that the supporting leg of must strictness controlling well stretches and shortens promptly guarantees position that supporting leg the stretches more close vertical position in position than shortening, and the gross energy of system in swing process increased.In the method that this energy is mended, only considered that the power that adds on the supporting leg mends effect into energy to system, because we have only considered that mass concentration is at hip, the model of having ignored the shank quality, lead leg to the not influence of energy of system, so in walking, keep crooked constant, and hypothesis is led leg, and can to put with the supporting leg angle be the lock hip state of a fixed value.

Biped robot of the present invention has the characteristic of the progressive balance of energy, and the performance of this specific character is as follows.Walk in the process in a walking, the increase of system capacity is only stretched with bent position relevant, and irrelevant with the initial speed of supporting leg with supporting leg.When the robot supporting leg stretch with bent position fixing after, it mends the energy of going in each step of walking be exactly a fixing constant, when the energy of mending the energy of going into and the collision damage of leading leg is the same, the walking of robot just enters limit cycle, and the starting velocity after the collision is the speed at fixed point place.If the initial speed of robot is greater than the speed at fixed point place, the energy of collision damage is proportional to rate of onset owing to lead leg, so the energy of collision damage greater than mend into energy, thereby next step starting velocity is reduced, up to equating with fixed point place speed; Otherwise, if the initial speed of robot less than the speed at fixed point place, the energy of collision damage less than mend into energy, thereby next step starting velocity is increased, equate up to speed with the fixed point place.

Biped robot's traveling method of the present invention is characterised in that, contains following steps successively:

Step (1) is constructed a biped robot, and shown in Fig. 3 (b), its step is as follows:

Step (1.1), set up being connected of trunk 1 and first thigh 4 and second thigh 5: this trunk 1 is captiveed joint respectively with the first hip joint motor 2 of the coaxial placement in the left and right sides and the body of the second hip joint motor 3, and the rotary output axis of the described first hip joint motor 2 is connected with described first thigh 4, the rotary output axis of the described second hip joint motor 3 is connected with described second thigh 5

Step (1.2), set up described first thigh 4 and first shank 7, second thigh 5 is connected with second shank 9: the end of this described first thigh 4 is captiveed joint with the body of the first knee joint motor 6, the rotary output axis of this first knee joint motor 6 is connected with first shank 7, the end of this described second thigh 5 is captiveed joint with the body of the second knee joint motor 8, the rotary output axis of this second knee joint motor 8 is connected with second shank 9

Step (1.3) all adopts servomotor at four motors described in step (1.1), the step (1.2), uses S respectively _Hip1, S _Hip2Represent the anglec of rotation of the described first hip joint motor 2 and the second hip joint motor 3, use S respectively _Knee1, S _Knee2The anglec of rotation of representing the described first knee joint motor 6 and the second knee joint motor 8, and with described four motors of PC control, wherein: described S _Hip1Be the angle of described first thigh 4 with trunk 1 vertical direction, S when the end of this first thigh 4 is positioned at trunk 1 the place ahead _Hip1＞0, and S when being positioned at trunk 1 rear _Hip1＜0, described S _Hip2Be the angle of described second thigh 5 with trunk 1 vertical direction, S when the end of this second thigh 5 is positioned at trunk 1 the place ahead _Hip2＞0, and S when being positioned at trunk 1 rear _Hip2＜0; Described S _Knee1Be the angle between described first shank 7 and first thigh 4, S when this first shank 7 is crooked backward with respect to described first thigh 4 _Knee1＞0, S when both are parallel _Knee1=0, described S _Knee2Be the angle between described second shank 9 and second thigh 5, S when this second shank 9 is crooked backward with respect to described second thigh 5 _Knee2＞0, S when both are parallel _Knee2=0,

Step (1.4), the signal input end of each motor links to each other with the control signal output ends of a upper computer respectively described in this step (1.1), step (1.2), the step (1.3);

Step (2), in described upper computer, set a gait cycle T, described gait cycle T refers to collide the time of being experienced to leading leg from a zero hour in step, and wherein, the zero hour, t=0 was meant the liftoff moment of leading leg, collision constantly t=T is meant and leads leg and ground bumps, promptly a gait cycle finishes, the moment that next gait cycle begins, at this in a flash, supporting leg before becomes leads leg, and leading leg before becomes supporting leg.

Step (3) in described upper computer, in a described gait cycle, is provided with five key frames, two crucial joint angles θ and α, as shown in Figure 4:

First key frame (figure A), when being positioned at t=0, the initial attitude in one step of decision robot, wherein, θ=-θ ₀, θ ₀Be a non-negative constant, the angle during expression t=0 between described two equivalent legs, it has determined the size of stride; α=α ₀, α ₀Be a non-negative constant, expression t=0 is the angle of bend of described supporting leg thigh 2 with respect to equivalent supporting leg 4.

Second key frame (figure B) is positioned at t=T ₁The time, wherein: α=α ₀, identical with α in first key frame, represent that the length of equivalent supporting leg 4 remains unchanged between first key frame and second key frame.What this key frame was represented is the starting point that supporting leg stretches.

The 3rd key frame (figure C) is positioned at t=T ₂The time, wherein: α=0, expression supporting leg knee joint stretches, and the hip barycenter rises to vertex.From three key frames of second key frame to the is to mend process into energy to system, and knee joint also is in case of bending because lead leg this moment, so can avoid leading leg in the process of walking shank and ground bump.

The 4th key frame (figure D) is positioned at t=T ₃The time, wherein: α=α ₀, expression supporting leg knee joint bending returns previous status, is processes that supporting leg shortens from four key frames of the 3rd key frame to the, and this is that two legs are isometric in order to guarantee to collide, and becomes at next step supporting leg and to keep case of bending when leading leg.

The 5th key frame (figure E), when being positioned at t=T, decision collision robot pose constantly, wherein: θ=θ ₀, the expression collision is the angle between the two equivalent legs constantly; α=α ₀, from the 4th key frame to the five key frames, supporting leg remains unchanged.After bumping with ground, supporting leg becomes leads leg, and leading leg becomes supporting leg.

Step (4.1), described upper computer are controlled described robot ambulation successively according to the following steps, set the period T that every row makes a move, three material time T ₁, T ₂, T ₃, be t computing time, and t is since 0, and described upper computer is calculated as follows the θ every the t time, the value of α

(1)

$\mathrm{\&alpha;}=\left\{\begin{array}{cc}{\mathrm{\&alpha;}}_0& 0\&le;t\mathrm{mod}T<{\mathrm{<figure-callout\; id="1"\; label="T"\; filenames="HSA00000209917400013.png,HSA00000209917400021.png"\; state="\{\{state\}\}">T</figure-callout>}}_1\\ \frac{{\mathrm{\&alpha;}}_0}{2}\cos \frac{\mathrm{\&pi;}(t-T_1)}{T_2-{\mathrm{<figure-callout\; id="1"\; label="T"\; filenames="HSA00000209917400013.png,HSA00000209917400021.png"\; state="\{\{state\}\}">T</figure-callout>}}_1}+\frac{{\mathrm{\&alpha;}}_0}{2}& {\mathrm{<figure-callout\; id="1"\; label="T"\; filenames="HSA00000209917400013.png,HSA00000209917400021.png"\; state="\{\{state\}\}">T</figure-callout>}}_1\&le;t\mathrm{mod}T<{\mathrm{<figure-callout\; id="2"\; label="T"\; filenames="HSA00000209917400011.png,HSA00000209917400012.png"\; state="\{\{state\}\}">T</figure-callout>}}_2\\ \frac{{\mathrm{\&alpha;}}_0}{2}\cos \frac{\mathrm{\&pi;}(t-T_3)}{T_2-{\mathrm{<figure-callout\; id="3"\; label="T"\; filenames="HSA00000209917400011.png,HSA00000209917400012.png"\; state="\{\{state\}\}">T</figure-callout>}}_3}+\frac{{\mathrm{\&alpha;}}_0}{2}& {\mathrm{<figure-callout\; id="2"\; label="T"\; filenames="HSA00000209917400011.png,HSA00000209917400012.png"\; state="\{\{state\}\}">T</figure-callout>}}_2\&le;t\mathrm{mod}T<{\mathrm{<figure-callout\; id="3"\; label="T"\; filenames="HSA00000209917400011.png,HSA00000209917400012.png"\; state="\{\{state\}\}">T</figure-callout>}}_3\\ {\mathrm{\&alpha;}}_0& {\mathrm{<figure-callout\; id="3"\; label="T"\; filenames="HSA00000209917400011.png,HSA00000209917400012.png"\; state="\{\{state\}\}">T</figure-callout>}}_3\&le;t\mathrm{mod}T<T\end{array}\right.$

(2)

Can obtain θ=f by following formula _θ(t), α=f _α(t) two curves, they are respectively the curves of hip angle and supporting leg knee joint bending angle, as shown in Figure 5, and variable θ, α is continuous about the first derivative of t.

Step (4.2), in above-mentioned upper computer, be calculated as follows when step number is n (n is t and the T integer part of division result mutually), at above-mentioned walking parameter θ, the α and the kneed angle of bend β that leads leg (because supporting leg just remains unchanged becoming the patella of leading leg, i.e. β=α ₀) value under, the anglec of rotation of described each motor of biped robot.When n is odd number, S _Hip1, S _Knee1Be respectively described supporting leg hip joint and kneed angle, S _Hip2, S _Knee2Be respectively described hip joint and the kneed angle of leading leg, when n is even number, S _Hip2, S _Knee2Be respectively described supporting leg hip joint and kneed angle, S _Hip1, S _Knee1Be respectively described hip joint and the kneed angle of leading leg, that is to say when n is become this odd number and added 1 formed even number by odd number, as the supporting leg of first thigh with walk to finish the back as leading leg of second thigh in a walking and exchange.

$\left\{\begin{array}{c}{\mathrm{<figure-callout\; id="1"\; label="S\; hip"\; filenames="HSA00000209917400013.png,HSA00000209917400021.png"\; state="\{\{state\}\}">S</figure-callout>}}_{\mathrm{hip}}=-\frac{1}{2}\mathrm{\&theta;}+\mathrm{\&alpha;}\\ {\mathrm{<figure-callout\; id="2"\; label="S\; hip"\; filenames="HSA00000209917400011.png,HSA00000209917400012.png"\; state="\{\{state\}\}">S</figure-callout>}}_{\mathrm{hip}}=\frac{1}{2}\mathrm{\&theta;}+\mathrm{\&beta;}\\ {\mathrm{<figure-callout\; id="1"\; label="S\; knee"\; filenames="HSA00000209917400013.png,HSA00000209917400021.png"\; state="\{\{state\}\}">S</figure-callout>}}_{\mathrm{knee}}=2\mathrm{\&alpha;}\\ {\mathrm{<figure-callout\; id="2"\; label="S\; knee"\; filenames="HSA00000209917400011.png,HSA00000209917400012.png"\; state="\{\{state\}\}">S</figure-callout>}}_{\mathrm{knee}}=2\mathrm{\&beta;}\end{array}\right.,n=\mathrm{1,3,5,7,9}...$

(3)

$\left\{\begin{array}{c}{\mathrm{<figure-callout\; id="1"\; label="S\; hip"\; filenames="HSA00000209917400013.png,HSA00000209917400021.png"\; state="\{\{state\}\}">S</figure-callout>}}_{\mathrm{hip}}=\frac{1}{2}\mathrm{\&theta;}+\mathrm{\&beta;}\\ {\mathrm{<figure-callout\; id="2"\; label="S\; hip"\; filenames="HSA00000209917400011.png,HSA00000209917400012.png"\; state="\{\{state\}\}">S</figure-callout>}}_{\mathrm{hip}}=-\frac{1}{2}\mathrm{\&theta;}+\mathrm{\&alpha;}\\ {\mathrm{<figure-callout\; id="1"\; label="S\; knee"\; filenames="HSA00000209917400013.png,HSA00000209917400021.png"\; state="\{\{state\}\}">S</figure-callout>}}_{\mathrm{knee}}=2\mathrm{\&beta;}\\ {\mathrm{<figure-callout\; id="2"\; label="S\; knee"\; filenames="HSA00000209917400011.png,HSA00000209917400012.png"\; state="\{\{state\}\}">S</figure-callout>}}_{\mathrm{knee}}=2\mathrm{\&alpha;}\end{array}\right.,n=2,4,6,\mathrm{8,10}...$

(4)

The parameter that gait method of designing of the present invention relates to mainly is time variable T, T ₁, T ₂, T ₃With two angles of θ, α, in operating process, need regulate parameter accordingly according to the actual result of robot.

Power biped robot traveling method of the present invention is based on passive walking principle, initiatively shortens the potential energy that supporting leg comes the replenishment system barycenter again by initiatively extending earlier in a walking is walked.This method has been eliminated and has been led leg and collision on the ground moment is mended the influence that walking stability is caused into energy, can make robot reach higher walking stability, and it only needs open loop control, and realization is simple and calculated amount is very little, therefore is applicable to the occasion that real-time is had relatively high expectations.In addition, it will be added on the supporting leg in the control sets, and does not need to control leading leg, and has reduced the variable of control, and this control method can make system mend into energy be a fixed value, thereby have the advantage of the progressive balance of energy.

Description of drawings

Fig. 1 is robot model's a scheme drawing.

Fig. 2 there is shown for the energy conversion principle figure of walking that process is walked in a walking and supporting leg is mended into energy and pendulum impact expended energy principle.

Fig. 3 is the scheme drawing of robot mechanism figure and four crucial motor corners, and wherein Fig. 3 (a) illustrates the robot lateral plan, and the robot front elevation (b) is shown.

Fig. 4 is a gait key frame scheme drawing, and A is first key frame, and B is second key frame, and C is the 3rd key frame, and D is the 4th key frame, and E is the 5th key frame.

Fig. 5 is the change curve of 2 angled key, wherein realizes illustrating the track of θ, is shown in dotted line the track of α.

Fig. 6 is power traveling method realization flow figure.

The specific embodiment

Fig. 3 is the scheme drawing of robot construction used herein and four joint angles, the realization of biped robot's traveling method of the present invention needs five key frames, as shown in Figure 4, in these five key frames, first key frame has determined the attitude of a step initial time, the 5th key frame has determined step collision attitude constantly, has also determined the size of stride simultaneously.Second key frame to the, three key frames are processes of supporting leg elongation, determined benefit to go into what of energy, the 3rd key frame to the four key frames are processes that supporting leg shortens, be that two legs are isometric in order to guarantee to collide, and make supporting leg become and keep the state of shortening when leading leg at next step, this process is the process of degradation of energy, in order to guarantee that the gross energy of system increases before collision, the energy that the energy of going into must shorten loss greater than supporting leg is mended in the supporting leg elongation, this just needs strict control second, the relative position of third and fourth these three key frames is as long as the position of elongation just can guarantee that with respect to the more close vertical position in position that shortens the gross energy of system increases.

The above parameter T, T ₁, T ₂, T ₃And θ ₀, α ₀Value in the following manner.

Rule of thumb provide one group of initial value, determine T earlier ₁, T ₂, T ₃These three are worth constantly, and this is the more close vertical position in position that shortens for the position ratio that guarantees the supporting leg elongation, for convenience, generally all gets T ₂Key frame is vertical position, i.e. T ₂=T/2, T ₁And T ₃As long as satisfy T ₂-T ₁＜T ₃-T ₂That's all, then actual robot is operated, keeping T, T ₁, T ₂, T ₃Under the unmodified situation, begin when robot is from t=0 as described to fall down forward after the walking, α is described ₀Excessive, it is excessive to mend the energy of going into, and makes α ₀Subtract 1 °, so repeat, till this robot can be walked; Begin when robot is from t=0 as described to fall down backward after the walking, α is described ₀Too small, it is too small to mend the energy of going into, and makes α ₀Add 1 °, so repeat, till this robot can be walked.

If adjust α ₀Can not make robot ambulation, then need to adjust other parameter, if robot falls forward, also can be by reducing T ₁(supporting leg is stretched further from vertical position) or reduce T3 (make supporting leg shorten the more close vertical position in position) reduce system mend into energy; If robot falls backward, also can be by increasing T ₁Perhaps T ₃Come the increase system mend into energy.At last can also be by selecting θ again ₀And T, come adjustment data according to above step again, make robot can on the level land, realize stable different strides, the walking of different cycles.

In walking, angled key θ shown in Figure 1 and the value of α are calculated according to above-described key frame, and its path of motion is the junction curve between the key frame.Continuous for the cireular frequency that guarantees each joint of robot, use smooth curve to connect between the key frame, promptly the first derivative of curve is continuous.Fig. 5 has provided a kind of use straight line and trigonometric function curve ways of connecting, but scope of the present invention is not limited to this connection mode.

The iterative process that is embodied as following two steps of biped robot's traveling method of the present invention: (1) PC control walking stage; (2) artificial parameter is regulated the stage.In the stage (1) at first by one group of θ of artificial setting ₀=50 °, α ₀=25 °, T=0.4s, T ₁=0.1s, T ₂=0.2s, T ₃=0.36s, after determining these parameter values, computing machine as upper computer just uses smooth curve to connect key frame, calculate each θ and α value constantly, be converted into four motor angle values of robot afterwards again by (3) and (4) formula, and send to each motor on the robot, make its path of motion rotation, to realize the walking action by appointment.When n is odd number, the S among Fig. 3 _Hip1, S _Knee1Be supporting leg joint angle, S _Hip2, S _Knee2Be the joint angle of leading leg, S when n is even number _Hip2, S _Knee2Be supporting leg joint angle, S _Hip1, S _Knee1Be the joint angle of leading leg.Treating that robot places begins it to be put in ground running and to observe the walking effect after the action in the air, can not walk if robot is fallen down, and then changes the stage (2) over to.Under the parameter of above-mentioned setting, robot can fall when walking on the level land backward.

Stage (2) is the whole stage of people's wage adjustment, according to the walking effect of robot in the stage (1) hand adjustment is carried out in the parameter setting in the upper computer by the people in this stage, and its control method is as follows: that at first adjust is two critical angle, wherein α ₀Determined the size that walking mends energy,, can make α if fall down forward behind the robot ambulation in the stage (1) ₀ Subtract 1 °; If robot is fallen down backward, can make α ₀Add 1 °.If robot can be walked, illustrate that the walking condition satisfies, but fine tuning α ₀Optimize collision constantly.If adjust α ₀Can not make robot ambulation, then need to adjust other parameter, if robot falls forward, also can be by reducing T ₁Perhaps reduce T ₃Reduce system mend into energy; If robot falls backward, also can be by increasing T ₁Perhaps T ₃The increase system mend into energy.At last can also be by selecting θ again ₀And T, come adjustment data according to above step again, make can be on the level land stable walking of robot.Under the parameter of setting in the stage (1), robot begins and can fall forward, by reducing α ₀, work as α ₀When being reduced to 16 °, robot has been realized the stabilized walking on the level land.

Claims (6)

1. a walking method for dynamic biped robot is characterized in that, contains following steps successively: step (1), construct a biped robot, and its step is as follows:

Step (1.1), set up being connected of trunk and first thigh and second thigh:

This trunk is captiveed joint respectively with the first hip joint motor of the coaxial placement in the left and right sides and the body of the second hip joint motor, and the rotary output axis of the described first hip joint motor is connected with described first thigh, the rotary output axis of the described second hip joint motor is connected with described second thigh

Step (1.2) is set up described first thigh and first shank, and second thigh is connected with second shank:

The end of this described first thigh is captiveed joint with the body of the first knee joint motor, and the rotary output axis of this first knee joint motor is connected with first shank,

The end of this described second thigh is captiveed joint with the body of the second knee joint motor, and the rotary output axis of this second knee joint motor is connected with second shank,

Step (1.3) all adopts servomotor at four motors described in step (1.1), the step (1.2), uses S respectively _Hip1, S _Hip2Represent the anglec of rotation of the described first hip joint motor and the second hip joint motor, use S respectively _Knee1, S _Knee2The anglec of rotation of representing the described first knee joint motor and the second knee joint motor, and with described four motors of PC control, wherein:

Described S _Hip1Be the angle of described first thigh and trunk vertical direction, S when the end of this first thigh is positioned at trunk the place ahead _Hip1＞0, and S when being positioned at the trunk rear _Hip1＜0,

Described S _Hip2Be the angle of described second thigh and trunk vertical direction, S when the end of this second thigh is positioned at trunk the place ahead _Hip2＞0, and S when being positioned at the trunk rear _Hip2＜0,

Described S _Knee1Be the angle between described first shank and first thigh, S when this first shank is crooked backward with respect to first thigh _Knee1＞0, S during both same straight lines _Knee1=0,

Described S _Knee2Be the angle between described second shank and second thigh, S when this second shank is crooked backward with respect to second thigh _Knee2＞0, S during both same straight lines _Knee2=0,

Step (1.4), the signal input end of each motor links to each other with the control signal output ends of a upper computer respectively described in this step (1.1), step (1.2), the step (1.3);

Step (2), in described upper computer, set a gait cycle T, described gait cycle T refers to collide the time of being experienced to leading leg from a zero hour in step, wherein, t=0 was meant and regarded leading leg of second thigh liftoff moment as the zero hour, collision constantly t=T is meant and leads leg and ground bumps, promptly a gait cycle finishes, the moment that next gait cycle begins, at this in a flash, the supporting leg that is considered as second thigh this moment becomes leads leg, and leading leg before becomes supporting leg, described walking parameter comprises: θ, α, β, unit are angle, wherein:

θ, be lead leg angle between (7) of equivalent supporting leg (4) and equivalence, described equivalent supporting leg (4) is used by the top of supporting leg thigh (2) and is represented to the terminal line of this supporting leg shank (3), equivalence lead leg (7) use by the top of the thigh of leading leg (5) and represent to the terminal line of this shank of leading leg (6)

α is the angle between described supporting leg thigh (2) and the equivalent supporting leg (4), determines the length of equivalent supporting leg (4),

β is lead leg angle between (7) of the described thigh of leading leg (5) and equivalence, the lead leg length of (7) of decision equivalence, and in the process of walking, leading leg remains unchanged, so β is a fixed constant,

When described equivalence lead leg (7) be positioned at equivalent supporting leg (4) θ＞0 before the time, θ in the time of afterwards＜0,

α＞0 when the knee joint bending of described supporting leg, α when the supporting leg knee joint stretches=0,

β＞0 when described knee joint bending of leading leg, the β when knee joint of leading leg stretches=0;

Step (3) in described upper computer, in a described gait cycle, is provided with five key frames, two crucial joint angles θ and α;

First key frame, when being positioned at t=0, the initial attitude in one step of decision robot, wherein, θ=-θ ₀, θ ₀Be a non-negative constant, expression is the angle between described two equivalent legs during t=0, has determined the size of stride; α=α ₀, α ₀Be a non-negative constant, expression t=0 is the angle of bend of described supporting leg thigh with respect to equivalent supporting leg,

Second key frame is positioned at t=T ₁The time, wherein: α=α ₀, identical with α in first key frame, represent that the length of equivalent supporting leg remains unchanged between first key frame and second key frame, what this key frame was represented is the starting point that supporting leg stretches,

The 3rd key frame is positioned at t=T ₂The time, wherein: α=0, expression supporting leg knee joint stretches, and the hip barycenter rises to vertex.From three key frames of second key frame to the are processes of supporting leg elongation, be to mend process, and knee joint also is in case of bending because lead leg this moment into energy to system, so can avoid leading leg in the process of walking shank and ground bump,

The 4th key frame is positioned at t=T ₃The time, wherein: α=α ₀, expression supporting leg knee joint bending returns previous status, is processes that supporting leg shortens from four key frames of the 3rd key frame to the, and this is that two legs are isometric in order to guarantee to collide, and becomes at next step supporting leg and to keep case of bending when leading leg,

The 5th key frame, when being positioned at t=T, decision collision robot pose constantly, wherein: θ=θ ₀, the expression collision is the angle between the two equivalent legs constantly; α=α ₀, from the 4th key frame to the five key frames, supporting leg remains unchanged, and after bumping with ground, supporting leg becomes leads leg, and leading leg becomes supporting leg,

Step (4), described upper computer are controlled described robot ambulation successively according to the following steps:

Step (4.1) is set the period T that every row makes a move, three material time T ₁, T ₂, T ₃, meter

Evaluation time is t, and t is since 0, and described upper computer is calculated as follows the θ every the t time, the value of α

(1)

$\mathrm{\&alpha;}=\left\{\begin{array}{cc}{\mathrm{\&alpha;}}_0& 0\&le;t\mathrm{mod}T<T_1\\ \frac{{\mathrm{\&alpha;}}_0}{2}\cos \frac{\mathrm{\&pi;}(t-T_1)}{T_2-T_1}+\frac{{\mathrm{\&alpha;}}_0}{2}& T_1\&le;t\mathrm{mod}T<T_2\\ \frac{{\mathrm{\&alpha;}}_0}{2}\cos \frac{\mathrm{\&pi;}(t-T_3)}{T_2-T_3}+\frac{{\mathrm{\&alpha;}}_0}{2}& T_2\&le;t\mathrm{mod}T<T_3\\ {\mathrm{\&alpha;}}_0& T_3\&le;t\mathrm{mod}T<T\end{array}\right.$

(2)

Can obtain θ=f by following formula _θ(t), α=f _α(t) two curves are respectively hip angle and supporting leg knee

The curve of arthrogryposis angle, variable θ, α is continuous about the first derivative of t,

Step (4.2), in above-mentioned upper computer, be calculated as follows when step number is n, n is t and the T integer part of division result mutually, at above-mentioned walking parameter θ, under the value of the α and the kneed angle of bend β that leads leg, because supporting leg just remains unchanged becoming the patella of leading leg, so β=α ₀, the anglec of rotation of described each motor of biped robot,

$\left\{\begin{array}{c}{S}_{\mathrm{hip}1}=-\frac{1}{2}\mathrm{\&theta;}+\mathrm{\&alpha;}\\ S_{\mathrm{hip}2}=\frac{1}{2}\mathrm{\&theta;}+\mathrm{\&beta;}\\ S_{\mathrm{knee}1}=2\mathrm{\&alpha;}\\ S_{\mathrm{knee}2}=2\mathrm{\&beta;}\end{array}\right.,n=\mathrm{1,3,5,7,9}...$

(3)

$\left\{\begin{array}{c}{S}_{\mathrm{hip}1}=\frac{1}{2}\mathrm{\&theta;}+\mathrm{\&beta;}\\ S_{\mathrm{hip}2}=-\frac{1}{2}\mathrm{\&theta;}+\mathrm{\&alpha;}\\ S_{\mathrm{knee}1}=2\mathrm{\&beta;}\\ S_{\mathrm{knee}2}=2\mathrm{\&alpha;}\end{array}\right.,n=2,4,6,\mathrm{8,10}...$

(4)

When n is odd number, S _Hip1, S _Knee1Be respectively described supporting leg hip joint and kneed angle, S _Hip2, S _Knee2Be respectively described hip joint and the kneed angle of leading leg, when n is even number, S _Hip2, S _Knee2Be respectively described supporting leg hip joint and kneed angle, S _Hip1, S _Knee1Be respectively described hip joint and the kneed angle of leading leg, that is to say when n is become this odd number and added 1 formed even number by odd number, as the supporting leg of first thigh with walk to finish the back as leading leg of second thigh in a walking and exchange.

2. a kind of walking method for dynamic biped robot according to claim 1 is characterized in that, described parameter T, T ₁, T ₂, T ₃And θ ₀, α ₀Value in the following manner:

The given T of elder generation, and get T ₂=T/2 determines T then ₁, T ₃, for the more close vertical position in position that the position ratio that guarantees the supporting leg elongation shortens, T ₁And T ₃Must satisfy T ₂-T ₁＜T ₃-T ₂, θ ₀, α ₀At satisfied 30 °＜θ ₀＜65 °, 10＜α ₀Given at random under＜50 the situation.

3. a kind of walking method for dynamic biped robot according to claim 1 is characterized in that, if operating personal is found following situation, handles respectively:

Described robot begins during from t=0 to fall down forward after the walking, and α is described ₀Excessive, it is excessive to mend the energy of going into, and makes α ₀Subtract 1 °, so repeat, till this robot can be walked,

Described robot begins during from t=0 to fall down backward after the walking, and α is described ₀Too small, it is too small to mend the energy of going into, and makes α ₀Add 1 °, so repeat, till this robot can be walked.

4. a kind of walking method for dynamic biped robot according to claim 1 is characterized in that, in any case if operating personal finds to adjust α ₀, all can not make robot ambulation stable, then, handle respectively by following situation:

Described robot begins during from t=0 to fall down forward after the walking, illustrate that the energy that benefit goes into is excessive, by reducing T ₁, so that supporting leg when stretching further from vertical position, perhaps reduce T ₃, the more close vertical position in position when supporting leg is shortened, with reduce system mend into energy, so repeat, till this robot can be walked,

Described robot begins during from t=0 to fall down backward after the walking, illustrate that to mend the energy of going into too small, then by increase T ₁, more close vertical position when supporting leg is stretched perhaps increases T ₃, the position when supporting leg is shortened is further from vertical position, with reduce system mend into energy, so repeat, till this robot can be walked.

5. a kind of walking method for dynamic biped robot according to claim 1 is characterized in that, at t=T, if operating personal is found following situation, handles respectively:

Described robot forward lean illustrates that collision too early, makes α constantly ₀Subtract 0.2 °, so repeat, when collision the machine person vertically till,

The hypsokinesis of described robot health illustrates that collision is constantly late excessively, makes α ₀Add 0.2 °, so repeat, when collision the machine person vertically till.

6. a kind of power type walking method for biped robot according to claim 1 is characterized in that, if no matter how operating personal is adjusted, all can not make described robot ambulation stable, perhaps can walk, but need to change leg speed, then θ ₀Increase or reduce 10 °, perhaps T is increased or reduce 0.1s, repeating step (2) and step (3), thus obtain different strides and gait cycle, realize the walking of friction speed.

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