CN101950176A - Method for performing zero moment point (ZMP) calibration autonomously by robot - Google Patents

Abstract

The invention provides a method for performing zero moment point (ZMP) calibration autonomously by a robot. The robot has at least two legs and feet, wherein the at least two legs can drive the robot to walk; the feet are connected with the legs through ankle joints respectively; and the feet are provided with force sensors. The method comprises the following steps of: calculating the projection of a barycenter of the robot on the ground according to each part and the position thereof of the robot, wherein the robot is supported by a single foot to maintain a certain stable fixed posture and the part above the ankle joint of the supporting foot of the robot is seen as a mass point; adjusting the ankle joint of the supporting foot of the robot so as to make the projection of the barycenter spread over the surface of the supporting foot; and obtaining a table by sampling, wherein in the table, a true ZMP corresponds to the ZMP measured by the force sensors. The robot can perform the ZMP calibration according to the projection of the barycenter of the robot and the movement of the ankle joints, so the method has the advantages of no need of human intervention, high efficiency, a large number of sampling points, high precision and low requirement on a mounting environment.

Description

A kind of robot autonomous method that ZMP demarcates of carrying out

Technical field

The present invention relates to a kind ofly to the ZMP of robot scaling method, particularly a kind of anthropomorphic robot independently carries out the scaling method of foot ZMP.

Background technology

Anthropomorphic robot (hereinafter to be referred as robot) is the same with the people, is to move by the walking realization of two legs.Its both legs structure with the mankind seemingly, more traditional wheeled and caterpillar type robot has better maneuverability, especially only has the occasion of the discontinuous contact point that disperses more to embody superiority at broken terrain, stair and with ground.But the biped robot has essential unsettled characteristics, falls down easily.

In order to make robot ambulation, must robot be controlled in real time according to the current oneself state of current environmental information and robot, the change that overcomes environment is with uncertain, make robot can be in actual environment stabilized walking.

When the control apery robot stabilized walking, need know a lot of parameters of anthropomorphic robot, such as the attitude of health, speed, acceleration, barycenter, ZMP is ordered or the like, and wherein ZMP (Zero MomentPoint) has used in known a variety of control methods.So-called ZMP, the moment that is ground force is that point of zero.ZMP is by being installed in the six-dimension force sensor ergometry and the moment of foot, calculating by the ZMP computing formula more at present.Since the measuring error of force transducer, installation environment, many-sided influences such as precision and error after force transducer installs, need be demarcated it, and purpose is to record real ZMP point with force transducer.

Prior art is normally demarcated some fixing point on the robot instep, by translation, and rotation, mathematical measures such as linearization reach the purpose of demarcating whole instep.Specific implementation is at first to choose the point of fixity at robot instep edge, such as eight more special point of fixity as shown in Figure 3, the coordinate of these eight points is known, apply an acting force that makes progress perpendicular to instep for the instep of robot at these points then, the power that six-dimension force sensor measures and the value of moment have been obtained, by the computing formula of ZMP, can draw the coordinate of these points of actual measurement.Often because the influence of each side factor, the coordinate figure that calculates with formula has certain deviation with actual coordinate figure, at this moment by the coordinate system translation, and rotation, mathematical measures such as linearization are coincide the coordinate figure that calculates and actual coordinate figure as far as possible.

Since the measuring error of force transducer, installation environment, many-sided influences such as precision and error; Or some part timing signal of sole needs to correct, and some part does not need to correct, if whole sole is all corrected or do not corrected, causing putting the ZMP that calibrated sensor measurement goes out by these has certain error with real ZMP.And generally need the demarcation personnel to carry out craft and repeatedly demarcate, artificial application of force direction is difficult to reach the requirement perpendicular to instep, and the limited amount of the point of demarcating, and is difficult to cover whole instep, and very consuming time, automaticity is not high.

Summary of the invention

At above-mentioned technical matters of the prior art, the object of the present invention is to provide a kind of method of utilizing the automatic whole instep ZMP of demarcation of center of gravity of robot self.Use this method, robot can demarcate ZMP automatically, and obtains the controlled ZMP of error.

The present invention realizes by the following technical solutions.

A kind of method of the walking mobile device being carried out the ZMP demarcation, described walking mobile device has can drive at least two shanks that its walking is moved, and the foot that is connected by ankle-joint respectively with described shank, described foot is equipped with force transducer, and described method comprises:

Allow described walking mobile device list pin support and keep certain stable anchor, regard the part more than the feet ankle-joint of walking mobile device as a particle, according to described each parts of walking mobile device and position thereof, calculate its barycenter projection on the ground;

Regulate the ankle-joint of the feet of walking mobile device, make the projection of described barycenter travel through the instep of described feet;

By sampling, obtain a true ZMP and the corresponding form of ZMP that goes out by described force sensor measuring.

Above-mentioned and/or others of the present invention are also carried out the system that ZMP demarcates to robot and are realized by providing a kind of, described robot has can drive at least two shanks that its walking is moved, and the foot that is connected by ankle-joint respectively with described shank, described foot is equipped with force transducer, it is characterized in that described system comprises:

Be used to allow described robot list pin support and keep certain stable anchor, regard the part more than the feet ankle-joint of robot as a particle, according to each parts of described robot and position thereof, calculate the device of its barycenter projection on the ground;

Be used to regulate the ankle-joint of the described feet of robot, make the projection of described barycenter travel through the device of the instep of described feet;

Be used for by sampling, obtain the device of a true ZMP and the corresponding form of ZMP that goes out by described force sensor measuring.

Compared with prior art, the present invention has obtained following technique effect:

(1) need not manually to demarcate point of fixity, robot finishes the demarcation of ZMP automatically, has got rid of artificial factor, and is simultaneously time saving and energy saving, the automaticity height.

(2) installation environment no matter, What gives such as precision are as long as situation determines that the ZMP through technical solution of the present invention obtains can both reflect real situation.

(3) number of Cai Yang point is more, and can artificially control, and precision is higher, and the scope of error is controlled.

Description of drawings

Fig. 1 is anthropomorphic robot model simplification figure during according to demarcation ZMP of the present invention.

Fig. 2 is the moving direction figure according to anthropomorphic robot center of gravity of the present invention.

Fig. 3 is that robot of the prior art instep is demarcated synoptic diagram.

Embodiment

Anthropomorphic robot model simplification figure when Fig. 1 illustrates according to demarcation ZMP of the present invention.Robot comprises simplification particle 1, ankle-joint 2, force transducer 3, the instep 4 of feet ankle-joint with top.Ankle-joint can about and fore-and-aft direction rotation.ZMP records by six-dimension force sensor 3.

Fig. 2 is that example shows the direction that center of gravity of the present invention moves with the anthropomorphic robot right crus of diaphragm, partial parameters, the foundation of coordinate system.The sensor upper surface is d to the sole vertical range, p _RThe coordinate of expression ZMP.

Before each component-assembled of anthropomorphic robot, the position that can measure its barycenter after assembling is finished, by calculating, can access the barycenter of the robot of any attitude.Suppose to form m by N parts more than the robot anklebone _iBe the quality of i parts, p _iBe i the position of parts barycenter in the instep coordinate system, the position c that simplifies particle 1 so can calculate by formula (1).

$c=\left(\underset{i=1}{\overset{N}{\mathrm{\Σ}}}{m}_i{p}_i\right)/\underset{i=1}{\overset{N}{\mathrm{\Σ}}}{m}_i---\left(1\right)$

At first supporting leg keeps zero-bit, just fully straight leg state, fixing other joints except hip joint (before and after the hip and two joints that swing) by calculating, can obtain making the robot barycenter to pass through the angle of two hip joints of instep coordinate origin in instep projection coordinate.Make two hip joints forward the angle of calculating to, then robot is placed on the level ground, the initial point that the projection of barycenter at this moment just at the feet areal coordinate is.The above part of ankle-joint this moment can be regarded a particle as, and particle can calculate from formula (1) apart from the height L of ankle-joint.

By regulating ankle-joint 2, make the point 5 at barycenter certain edge of sole in the projection arrival Fig. 2 on ground, begin to demarcate ZMP then.The coordinate of postulated point 5 is (x ₅, y ₅), the angle of ankle-joint left-right rotation is θ, the angle that rotate front and back is

Can draw by geometric relationship

By top formula, the angular range of ankle-joint that can calculate four marginal points of corresponding instep is [θ _Min, θ _Max],

When the barycenter projection of robot moves on to a little 6 from putting 5, only need to change the angle of left-right rotation, the angle that rotate front and back is constant, when the barycenter projection of robot moves on to a little 7 from putting 6, the angle of rotating before and after only needing to change, the angle of left-right rotation is constant, and therefore by changing the angle of ankle-joint, the barycenter projection of robot can travel through convenient whole instep.

By regulating ankle-joint 2, barycenter projection is on the ground moved along direction shown in Figure 2 with speed slowly, simultaneously by force sensor measuring power and moment, power f=[f _x, f _y, f _z], moment τ=[τ _x, τ _y, τ _z], calculate the value of surveying ZMP then, computing formula is as follows:

p _Rx＝(-τ _y-f _xd)/f _z(2)

p _Ry＝(τ _x-f _yd)/f _z(3)

p _RxBe the value of ZMP in the x direction, p _RyBe the value of ZMP in the y direction.Note the position [c of sampling instant barycenter projection on instep _x, c _y] with the position [p of the ZMP of force transducer actual measurement _Rx, p _Ry].Allow projection travel through whole sole, can access a barycenter projection and show one to one with actual measurement ZMP.By the time interval and per two width of sampling between the row of regulating sampling, the sparse degree of regulating this table, thereby the size of adjusting maximum error.This table has been divided into a lattice-array to the sole of robot, and in robot actual motion process, we calculate the position p of ZMP by force transducer 3 _c=[p _x, p _y], the mode by tabling look-up obtains Pc and drops in certain grid again, two of grid is P1=[P1x to angular coordinate, P1y], P2=[P2x, P2y] and the position c1=[c1 of each self-corresponding projection _x, c1 _y], c2=[c2 _x, c2 _y], satisfy system of equations (4)

$\left\{\begin{array}{c}{P}_{1x}\≤P_x\≤P_{2x}\\ P_{1y}\≤P_y\≤P_{2y}\end{array}\right.---\left(4\right)$

Calculate the coordinate P of the ZMP that we need at last by formula (5) _m=[P _Mx, P _My].

$\left\{\begin{array}{c}{P}_{\mathrm{mx}}=c_{1x}+(P_x-P_{1x})/(P_{2x}-P_{1x})*(c_{2x}-c_{1x})\\ P_{\mathrm{my}}=c_{1y}+(P_y-P_{1y})/(P_{2y}-P_{1y})*(c_{2y}-c_{1y})\end{array}\right.---\left(5\right)$

From foregoing description as can be seen, the invention provides the method that a kind of robot autonomous ZMP of carrying out demarcates, wherein robot carries out the demarcation of ZMP according to the motion of self barycenter projection and ankle-joint, need not artificial interference, the efficient height, the sampled point number is many, the precision height, installation environment requires low.

Embodiments of the invention also can be configured to the ZMP of other robot that can walking moves or moving device is demarcated.Simultaneously, these robot or moving devices that can walking move also are not limited to have the form of two shanks.

Therefore, it will be appreciated by those skilled in the art that the present invention is not limited in the details of this paper description or illustrative method or structure, application or use.In fact, the modification of any appropriate or alternate embodiment all should comprise within the spirit and scope of the present invention.

Claims (8)

1. one kind is carried out the method that ZMP demarcates to the walking mobile device, described walking mobile device has can drive at least two shanks that its walking is moved, and the foot that is connected by ankle-joint respectively with described shank, described foot is equipped with force transducer, it is characterized in that described method comprises:

Allow described walking mobile device list pin support and keep certain stable anchor, regard the part more than the feet ankle-joint of walking mobile device as a particle, according to described each parts of walking mobile device and position thereof, calculate its barycenter projection on the ground;

Regulate the ankle-joint of the feet of walking mobile device, make the projection of described barycenter travel through the instep of described feet;

By sampling, obtain a true ZMP and the corresponding form of ZMP that goes out by described force sensor measuring.

2. method according to claim 1 is characterized in that described force transducer is used for ergometry and moment.

3. method according to claim 2 is characterized in that, when the ankle-joint of the described feet of regulating the walking mobile device, makes the projection of described barycenter overlap with ZMP.

4. method according to claim 3 is characterized in that, described method also comprises:

In actual applications, at first go out ZMP, drop on certain zone of form by searching ZMP that described form obtains measuring then, calculate ZMP at last through having revised by described force sensor measuring.

5. one kind is carried out the system that ZMP demarcates to robot, described robot has can drive at least two shanks that its walking is moved, and the foot that is connected by ankle-joint respectively with described shank, and described foot is equipped with force transducer, it is characterized in that described system comprises:

Be used to allow described robot list pin support and keep certain stable anchor, regard the part more than the feet ankle-joint of robot as a particle, according to each parts of described robot and position thereof, calculate the device of its barycenter projection on the ground;

Be used to regulate the ankle-joint of the described feet of robot, make the projection of described barycenter travel through the device of the instep of described feet;

Be used for by sampling, obtain the device of a true ZMP and the corresponding form of ZMP that goes out by described force sensor measuring.

6. system according to claim 5 is characterized in that described force transducer is used for ergometry and moment.

7. system according to claim 6 is characterized in that, when the ankle-joint of the described feet of regulating robot, makes the projection of described barycenter overlap with ZMP.

8. system according to claim 7 is characterized in that, described system also comprises:

Be used in actual applications, go out the device of ZMP by described force sensor measuring

Be used for by searching the device that ZMP that described form obtains measuring drops on certain zone of form,

Be used to calculate device through the ZMP that has revised.

Images