CN111114666A - All-dimensional gait switching method and system of parallel wheel-foot robot - Google Patents
All-dimensional gait switching method and system of parallel wheel-foot robot Download PDFInfo
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- CN111114666A CN111114666A CN201911379214.3A CN201911379214A CN111114666A CN 111114666 A CN111114666 A CN 111114666A CN 201911379214 A CN201911379214 A CN 201911379214A CN 111114666 A CN111114666 A CN 111114666A
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- B62D57/00—Vehicles characterised by having other propulsion or other ground- engaging means than wheels or endless track, alone or in addition to wheels or endless track
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Abstract
The invention discloses an all-dimensional gait switching method and system of a parallel wheel-foot robot, wherein the method comprises the following steps: establishing a kinematic model of the parallel wheel-foot robot; based on the kinematics model, taking the single-leg working space constraint and the walking stability constraint as consideration conditions, and specifying the straight walking intermittent gait and the rotating gait of the parallel wheel-foot robot; and switching the gaits according to the walking direction and the walking posture of the parallel wheel-foot robot based on the straight walking intermittent gaits and the rotating gaits. In the embodiment of the invention, the motion controllability of the parallel wheel-foot robot is improved, and the overall motion stability is effectively ensured.
Description
Technical Field
The invention relates to the field of robots, in particular to an all-dimensional gait switching method and system of a parallel wheel-foot robot.
Background
The foot type robot is a hotspot of research in the field of special robots at present, the foot type robots with different structures and different control modes have advantages in aspects of walking speed, load capacity, motion stability, flexibility and the like, but different structural designs all need to match with appropriate gait control algorithms to achieve optimal control performance. The structure of the current common tandem quadruped robot is simpler, the motion flexibility is higher, but the load capacity is smaller, the motion stability is poorer, the energy utilization rate is lower, and the robot is not suitable for the requirements of large load and complex road surface traffic. The hydraulically-driven parallel wheel-foot switching quadruped robot has the advantages of large load, high energy utilization rate, high motion stability and the like, has strong capability of fast passing in a wheel-foot type state, but each leg has eight degrees of freedom, and is redundant in mechanism and complex in gait control. In the prior art, a four-footed bionic robot with a knee joint parallel leg structure is provided, each parallel leg has three driving degrees of freedom, and three linear drivers can be utilized to cooperatively drive leg parts to perform bionic motion, such as front and back swinging, left and right swinging, bending of the leg parts around a knee joint and the like; the feet of the walking stick are connected in a buffering mode, and the shock absorption and energy storage can be recycled in a walking cycle. However, the four-legged bionic robot has a low energy utilization rate, only one legged passing mode is adopted, the moving speed on a flat road surface is low, and the load capacity is low due to the three-degree-of-freedom parallel connection mode, so that the requirement for large load capacity cannot be met.
Disclosure of Invention
The invention aims to overcome the defects of the prior art, and provides an all-dimensional gait switching method and system of a parallel wheel-foot robot.
In order to solve the above technical problem, an embodiment of the present invention provides an omnibearing gait switching method for a parallel wheel-foot robot, where the method includes:
establishing a kinematic model of the parallel wheel-foot robot;
planning a straight walking intermittent gait and a rotating gait of the parallel wheel-foot robot based on the kinematics model by taking the single-leg working space constraint and the walking stability constraint as consideration conditions;
and switching the gaits according to the walking direction and the walking posture of the parallel wheel-foot robot based on the straight walking intermittent gaits and the rotating gaits.
Optionally, the establishing a kinematic model of the parallel wheel-foot robot includes:
determining the position of the mass center of the parallel wheel-foot robot;
setting a positioning point of each leg in the four legs of the parallel wheel-foot robot on the robot body and a positioning point of the foot end of each leg;
the working space of each leg is set by taking the foot end positioning point of each leg as the center.
Optionally, the planning of the straight walking intermittent gait of the parallel wheel-foot robot comprises:
the foot end of each leg of the parallel wheel-foot robot is controlled to advance forwards along the same axial direction in sequence according to a certain rule, and the positioning points of the foot ends of the other three legs and the positioning points of the four legs on the robot body are kept unchanged while the foot end of each leg advances.
Optionally, the planning of the rotation gait of the parallel wheel-foot robot includes:
the center of mass of the parallel wheel-foot robot is used as the center of a circle, the distance from a foot end positioning point of any leg to the center of mass is used as the radius, and the rotating path of the parallel wheel-foot robot is specified;
the foot end of each leg of the parallel wheel-foot robot is controlled to rotate an angle along the rotating path in sequence according to a certain rule, the positioning points of the foot ends of the remaining three legs are kept unchanged while the foot end of each leg rotates, and the four legs are controlled to synchronously rotate corresponding angles in opposite directions at the positioning points of the robot body.
Optionally, switching the gait according to the walking direction and the walking posture of the parallel wheel-foot robot includes:
carrying out walking switching among the straight walking intermittent gaits according to the walking direction of the parallel wheel-foot robot;
and carrying out walking switching between the straight walking intermittent gait and the rotating gait according to the walking posture of the parallel wheel-foot robot.
In addition, the embodiment of the present invention further provides an omnibearing gait switching system of a parallel wheel-foot robot, wherein the system comprises:
the establishing module is used for establishing a kinematic model of the parallel wheel-foot robot;
the planning module is used for planning the straight walking intermittent gait and the rotating gait of the parallel wheel-foot robot by taking the single-leg working space constraint and the walking stability constraint as consideration conditions based on the kinematics model;
and the switching module is used for switching the gaits according to the walking direction and the walking posture of the parallel wheel-foot robot based on the straight walking intermittent gaits and the rotating gaits.
Optionally, the establishing module is further configured to determine a centroid position of the parallel wheel-foot robot; setting a positioning point of each leg in the four legs of the parallel wheel-foot robot on the robot body and a positioning point of the foot end of each leg; the working space of each leg is set by taking the foot end positioning point of each leg as the center.
Optionally, the planning module is further configured to control the foot end of each leg of the parallel wheel-foot robot to advance forward along the same axial direction in sequence according to a certain rule, and keep the positioning points of the foot ends of the remaining three legs and the positioning points of the four legs on the robot body unchanged while advancing at the foot end of each leg.
Optionally, the planning module is further configured to specify a rotation path of the parallel wheel-foot robot by taking a center of mass of the parallel wheel-foot robot as a center of circle and a distance from a foot end positioning point of any one leg to the center of mass as a radius; the foot end of each leg of the parallel wheel-foot robot is controlled to rotate an angle along the rotating path in sequence according to a certain rule, the positioning points of the foot ends of the remaining three legs are kept unchanged while the foot end of each leg rotates, and the four legs are controlled to synchronously rotate corresponding angles in opposite directions at the positioning points of the robot body.
Optionally, the switching module is further configured to switch the walking between the straight walking and the intermittent gait according to the walking direction of the parallel wheel-foot robot; and carrying out walking switching between the straight walking intermittent gait and the rotating gait according to the walking posture of the parallel wheel-foot robot.
In the embodiment of the invention, aiming at the characteristics of more complex control system and slower leg movement of the parallel wheel-foot robot, a proper gait walking control strategy and a gait conversion strategy are planned for the parallel wheel-foot robot, and through the combination of different gait strategies, the movement control performance of the parallel wheel-foot robot is greatly improved, and the overall movement stability is ensured. Aiming at the aspect of load feasibility, the pitch angle and the roll angle of the trunk of the parallel wheel-foot robot in the motion process are ensured to be within controllable amplitude, and the load-bearing forward stability is improved.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
Fig. 1 is a schematic flow chart of an omnibearing gait switching method of a parallel wheel-foot robot provided by an embodiment of the invention;
FIG. 2 is a schematic diagram of a kinematic model of a parallel wheel-foot robot provided by an embodiment of the invention;
FIG. 3 is a schematic diagram of a straight intermittent gait plan of a parallel wheel-foot robot provided by the embodiment of the invention;
FIG. 4 is a schematic diagram of a rotating gait planning path of the parallel wheel-foot robot provided by the embodiment of the invention;
FIG. 5 shows a parallel wheel-foot robot F provided by an embodiment of the present inventionxIntermittent gait switch to Fy-a schematic diagram of an intermittent gait;
FIG. 6 shows a parallel wheel-foot robot F provided by an embodiment of the present inventionxIntermittent gait switch to FO-a schematic diagram of a rotational gait;
FIG. 7 shows a parallel wheel-foot robot provided by an embodiment of the inventionOSwitching from rotational gait to Fx-a schematic diagram of an intermittent gait;
FIG. 8 shows a parallel wheel-foot robot F provided by an embodiment of the present inventionxIntermittent gait switch to Fy-a stability margin profile for intermittent gait;
FIG. 9 shows a parallel wheel-foot robot F provided by an embodiment of the present inventionxIntermittent gait switch to FO-stability margin graph of rotational gait;
FIG. 10 is a schematic diagram showing the relationship between the roll angle and the pitch angle of the trunk of the parallel wheel-foot robot and the gait transformation provided by the embodiment of the invention;
fig. 11 is a schematic structural diagram of an omnidirectional gait switching system of a parallel wheel-foot robot according to an embodiment of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Fig. 1 shows a flow chart of an omni-directional gait switching method of a parallel wheel-foot robot in an embodiment of the invention, the method comprises the following steps:
s101, establishing a kinematic model of the parallel wheel-foot robot;
it should be noted that, in the embodiment of the present invention, the parallel wheel-foot robot is a hydraulically driven parallel leg-foot robot, and each leg structure of the parallel wheel-foot robot has eight degrees of freedom. The description is given with reference to one leg structure: the six hydraulic cylinder linear reciprocating motion mechanisms enable legs of the robot to have the capability of six-degree-of-freedom motion, and the tail ends of the legs are provided with a wheel type structure driven by a motor and then provided with another motor to control the wheel type structure to rotate 360 degrees on a horizontal plane.
According to the schematic diagram of the kinematic model of the parallel wheel-foot robot shown in fig. 2, the establishment process of the kinematic model is explained as follows:
(1) determining the centroid position O of the parallel wheel-foot robot;
(2) defining a left front leg LF, a right front leg RF, a right rear leg RH and a left rear leg LH as four legs of the parallel wheel-foot robot, and setting a positioning point O of each leg in the four legs on a machine bodyi(i ═ 1,2,3,4) and the foot end positioning point O of each legi′(i＝1,2,3,4)；
(3) By locating the point O at the foot end of each legiA dashed circle having a center of (i ═ 1,2,3,4) and a radius of R is set as a tangent plane of the working space of each leg on the plane z ═ 0.
It should be noted that 1 may be replaced by the left front leg LF, 2 may be replaced by the left rear leg LH, 3 may be replaced by the right rear leg RH, and 4 may be replaced by the right front leg RF.
S102, planning a straight walking intermittent gait and a rotating gait of the parallel wheel-foot robot by taking single-leg working space constraint and walking stability constraint as consideration conditions based on the kinematics model;
in the embodiment of the present invention, the following description is first made of the planning of the straight walking intermittent gait of the parallel wheel-foot robot:
in summary, the foot end of each leg of the parallel wheel-foot robot is controlled to step forwards along the same axial direction in sequence according to a certain rule, and the positioning points of the foot ends of the other three legs and the positioning points of the four legs on the machine body are kept unchanged while the foot end of each leg steps forwards.
It is noted thatThe straight direction of the parallel wheel-foot robot can be along the positive direction of the X axis or along the negative direction of the X axis or along the positive direction of the Y axis or along the negative direction of the Y axis, and the invention is not limited. Correspondingly, the straight intermittent gait is subdivided into: fxIntermittent gait (positive X-axis), RxIntermittent gait (negative direction along the X axis), FyIntermittent gait (positive Y-axis) and RyIntermittent gait (negative direction along the Y axis).
Specifically, according to the schematic diagram of the parallel wheel-foot robot for the rectilinear intermittent gait planning shown in fig. 3, the plan view of the four legs RH, RF, LF, LH in the initial state is a parallelogram, and the centroid of the parallel wheel-foot robot is at the origin of the coordinate system, and the rectilinear intermittent gait of the parallel wheel-foot robot along the X axis is planned as follows:
state 3 → 4: at the moment, the four foot ends of the parallel wheel-foot robot form a new parallelogram, and the positioning points O of the four legs on the robot bodyi(i ═ 1,2,3,4) synchronously translated forward 1/2 steps along the X axis relative to the foot end anchor point, with the centroid position translated forward 1/2 steps relative to the initial position;
state 4 → 5: o's'LHThe leg foot ends step forward along the X axis according to the same step length, and simultaneously the foot end positioning points of the other three legs and the positioning points of the four legs on the machine body are kept unchanged;
state 5 → 6: o's'LFThe leg foot ends step forward along the X axis according to the same step length, and simultaneously the foot end positioning points of the other three legs and the positioning points of the four legs on the machine body are kept unchanged;
state 6 → 1: at the moment, the four foot ends of the parallel wheel-foot robot form a new parallelogram, and the positioning points O of the four legs on the robot bodyi(i is 1,2,3,4) synchronously translating 1/2 steps forwards along the X axis relative to the positioning point of the foot end, translating 1 step forwards relative to the initial position of the center of mass, and positioning point O of the foot end and the leg on the fuselageiThe relative position of (i ═ 1,2,3,4) returns to the initial state again.
In the embodiment of the present invention, the following description will be made of the planning of the rotational gait of the parallel wheel-foot robot:
roughly speaking, the center of mass of the parallel wheel-foot robot is taken as the center of a circle, the distance from a foot end positioning point of any leg to the center of mass is taken as the radius, and the rotating path of the parallel wheel-foot robot is specified; the foot end of each leg of the parallel wheel-foot robot is controlled to rotate an angle along the rotating path in sequence according to a certain rule, the positioning points of the foot ends of the remaining three legs are kept unchanged while the foot end of each leg rotates, and the four legs are controlled to synchronously rotate corresponding angles in opposite directions at the positioning points of the robot body.
The rotation direction of the parallel wheel-foot robot may be clockwise rotation or counterclockwise rotation, and is not limited in the present invention. Accordingly, the rotational gait is subdivided into: foRotational gait (clockwise rotation) and RoRotational gait (counterclockwise rotation).
Specifically, according to the schematic diagram of the path planned by the rotating gait of the parallel wheel-foot robot shown in fig. 4, the rotating path of the parallel wheel-foot robot is specified by taking the center of mass of the parallel wheel-foot robot as the center of circle and the distance from the foot end positioning point of any one leg to the center of mass as the radius, and the gait of the parallel wheel-foot robot rotating counterclockwise along the center of mass is planned as follows:
state 1: o's'RHThe leg foot ends swing by an angle theta along the rotating path, and simultaneously the positioning points of the foot ends of the remaining three legs are kept unchanged, at the moment, the positioning points of the four legs on the machine body synchronously rotate by an angle theta/4 anticlockwise relative to a static coordinate system, and when the machine body is in a static state, the foot ends of the four legs synchronously rotate by the angle theta/4 clockwise;
state 2: o's'RFThe leg foot end swings through an angle theta along the rotational path while maintaining the remaining threeThe positioning points of the foot ends of the four legs are unchanged, at the moment, the positioning points of the four legs on the machine body synchronously rotate by an angle theta/4 anticlockwise relative to a static coordinate system, and when the machine body is in a static state, the foot ends of the four legs synchronously rotate by the angle theta/4 clockwise;
state 3: o's'LFThe leg foot ends swing by an angle theta along the rotating path, and simultaneously the positioning points of the foot ends of the remaining three legs are kept unchanged, at the moment, the positioning points of the four legs on the machine body synchronously rotate by an angle theta/4 anticlockwise relative to a static coordinate system, and when the machine body is in a static state, the foot ends of the four legs synchronously rotate by the angle theta/4 clockwise;
and 4: o's'LHThe leg foot ends swing by an angle theta along the rotating path, and meanwhile, the positioning points of the foot ends of the remaining three legs are kept unchanged, at the moment, the positioning points of the four legs on the machine body synchronously rotate by an angle theta/4 anticlockwise relative to a static coordinate system, and when the machine body is in a static state, the foot ends of the four legs synchronously rotate by an angle theta/4 clockwise.
It should be noted that in the process of planning the straight walking intermittent gait and the rotating gait, the foot end positioning point of each leg of the parallel wheel-foot robot is always positioned in the working space, so as to meet the constraint condition of the working space of a single leg; the projection of the mass center on the ground is always positioned inside the supporting polygon, so that the walking stability constraint condition is met.
And S103, switching the gaits according to the walking direction and the walking posture of the parallel wheel-foot robot based on the straight walking intermittent gaits and the rotating gaits.
Specifically, the walking direction of the parallel wheel-foot robot is switched from the walking direction F between the straight walking and the intermittent walkingxIntermittent gait, said FyIntermittent gait, said Rx-intermittent gait and said Ry-switching between any two of the intermittent gaits.
In the embodiment of the invention, as shown in fig. 5, the parallel wheel-foot robot is planned to be FxIntermittent gait switch to FyThe motion strategy for intermittent gait is:
states 1-2: o's'RHThe foot end of the leg steps one step in the positive direction of the X axis while keeping the foot ends of the remaining three legsThe positioning points of the four legs on the robot body are unchanged, and at the moment, the parallel wheel-foot robot presents Fx-an intermittent gait trajectory;
state a: o's'RFThe leg foot ends step further along the positive direction of the Y axis according to the same step length, and simultaneously the positioning points of the foot ends of the other three legs and the positioning points of the four legs on the machine body are kept unchanged;
state b: o's'LHThe leg foot ends step further along the positive direction of the Y axis according to the same step length, and simultaneously the positioning points of the foot ends of the other three legs and the positioning points of the four legs on the machine body are kept unchanged;
and c, state c: at the moment, four foot ends of the parallel wheel-foot robot form a trapezoid, and positioning points O of four legs on the robot bodyi(i ═ 1,2,3,4) 1/2 steps of simultaneous positive Y-axis translation relative to the foot end anchor point, and 1/2 steps of positive Y-axis translation of the centroid position relative to the initial position;
and a state d: o's'LHThe leg foot ends step further along the positive direction of the Y axis according to the same step length, and simultaneously the positioning points of the foot ends of the other three legs and the positioning points of the four legs on the machine body are kept unchanged;
and a state e: o's'LFThe leg foot end is further along the positive direction of the Y axis according to the same step length, the positioning points of the foot ends of the other three legs are kept unchanged, and the positioning points O of the four legs on the machine bodyi(i ═ 1,2,3,4) 1/2 steps of simultaneous positive Y-axis translation relative to the foot end anchor point, and 1/2 steps of positive Y-axis translation of the centroid position relative to the initial position. At the moment, the motion trail of the parallel wheel-foot robot is from FxIntermittent gait switch to Fy-intermittent gait.
In the implementation process of the invention, because the walking stability of the parallel wheel-foot robot is in direct proportion to the stability margin, the gait switching strategy is simulated and verified by using dynamic simulation algorithm software on the basis. FIG. 8 shows the parallel wheel-foot robot composed of FxIntermittent gait switch to Fy-a graph of stability margins for intermittent gait, when the stability margin is always greater than 0, verifying said parallel connectionThe wheel-foot robot has no risk of toppling in the gait switching process.
Specifically, the walking posture of the parallel wheel-foot robot is switched between the straight intermittent gait and the rotating gait, namely, the walking posture is switched from the F posture to the rotating posturexIntermittent gait, said FyIntermittent gait, said Rx-intermittent gait and said Ry-any one of the intermittent gaits, with said Fo-rotational gait and said Ro-switching between any one of the rotational gaits.
In the embodiment of the invention, as shown in fig. 6, the parallel wheel-foot robot is planned to be FxIntermittent gait switch to FOThe motion strategy of the rotating gait is:
state 6 → 1: the positioning points of the four foot ends of the parallel wheel-foot robot form a new parallelogram, and the positioning points O of the four legs on the robot bodyi(i ═ 1,2,3,4) synchronously translated 1/2 steps in the positive X-axis direction relative to the foot end anchor point;
state a: the LH leg and the RF leg are positioned on the rotating path and are used as gait switching occasions to plan that the foot end positioning point of the LF leg moves to the rotating path from the current position, and meanwhile, the foot end positioning points of the other three legs and the positioning points of the four legs on the fuselage are kept unchanged;
state b: the LH leg, the RF leg and the LF leg are positioned on the rotating path and are used as gait switching occasions to plan a swing theta angle of a foot end positioning point of the RF leg along the rotating path, and meanwhile, foot end positioning points of the remaining three legs and positioning points of the four legs on the fuselage are kept unchanged;
and c, state c: the LH leg, the RF leg and the LF leg are positioned on the rotating path and are used as gait switching occasions, a foot end positioning point of the RH leg is planned to move to the rotating path from a current position, and then the fuselage rotates relative to the four foot ends by an angle theta. At the moment, the motion trail of the parallel wheel-foot robot is from FxIntermittent gait switch to FO-a rotating gait.
Similarly, dynamics are utilized in the practice of the inventionAnd simulation algorithm software carries out simulation verification on the stability margin of the parallel wheel-foot switching robot. FIG. 9 shows the parallel wheel-foot robot composed of FxIntermittent gait switch to FOA stability margin curve chart of the rotating gait, wherein the stability margin is always larger than 0, and the condition that the parallel wheel-foot robot has no risk of toppling in the gait switching process is verified.
In addition, another gait switching strategy is provided in the embodiment of the present invention, as shown in fig. 7, the parallel wheel-foot robot is planned to have a R-shapeOSwitching from rotational gait to FxThe motion strategy for intermittent gait is:
state a: moving a foot end location point of the RF leg from the rotational path to a center of a workspace of the RF leg;
state b: moving the foot end positioning point of the RH leg from the rotation path to 1/2 steps along the X-axis negative direction in the working space of the RH leg;
and c, state c: moving the foot end location point of the LF leg from the rotational path to 1/2 steps in the positive X-axis direction within the working space of the LF leg;
state 6 → 1: four foot end positioning points of the parallel wheel-foot robot form a parallelogram, the four foot end positioning points are kept unchanged, and the positioning points O of four legs on the robot bodyi(i-1, 2,3,4) is synchronously translated 1/2 steps in the positive X-axis direction relative to the foot end setpoint. At the moment, the motion trail of the parallel wheel-foot robot is from ROSwitching from rotational gait to Fx-intermittent gait.
It should be noted that, in fig. 3 to 7, the solid line circle is a projection of the working space of each leg in the z-axis direction, the internal black dot and solid line arrow are respectively a foot end point and a foot end movement direction corresponding to each leg, the dotted line arrow is a foot end trajectory curve of the swing phase, the X, Y axes are x and y axes of the coordinate system of the robot body, the O point is the centroid of the robot, the solid line arrow at the centroid is the centroid movement direction, and the foot end points connecting each support phase form a support polygon.
It should be noted that, in the gait switching and walking processes of the parallel wheel-foot robot, the stability of the robot carrying the load to move forward must be ensured. Therefore, in the embodiment of the invention, dynamic simulation algorithm software is utilized to perform simulation analysis on the change conditions of the roll angle and the pitch angle of the trunk of the parallel wheel-foot robot during movement, as shown in fig. 10, the stage 1 to the stage 4 are four times of gait switching processes respectively, the change range of the body angle of the parallel wheel-foot robot during the whole movement process is smaller, wherein the change range of the roll angle is-1.5 to 4.0 degrees, the change range of the pitch angle is-2.8 to 2.5 degrees, and the change ranges are within controllable ranges, so that the overall movement stability of the parallel wheel-foot robot is better.
Correspondingly, fig. 11 shows a schematic structural composition diagram of an omnidirectional gait switching system of a parallel wheel-foot robot in an embodiment of the present invention, where the system includes:
the establishing module 201 is used for establishing a kinematic model of the parallel wheel-foot robot;
specifically, the establishing module 201 is further configured to determine a centroid position of the parallel wheel-foot robot; setting a positioning point of each leg in the four legs of the parallel wheel-foot robot on the robot body and a positioning point of the foot end of each leg; the working space of each leg is set by taking the foot end positioning point of each leg as the center.
The planning module 202 is configured to plan a straight walking intermittent gait and a rotating gait of the parallel wheel-foot robot based on the kinematics model by taking a single-leg working space constraint and a walking stability constraint as consideration conditions;
specifically, the planning module 202 is further configured to control the foot end of each leg of the parallel wheel-foot robot to advance forwards along the same axial direction in sequence according to a certain rule, and keep the positioning points of the foot ends of the remaining three legs and the positioning points of the four legs on the robot body unchanged while advancing the foot end of each leg.
In addition, the planning module 202 is further configured to specify a rotation path of the parallel wheel-foot robot by taking a center of mass of the parallel wheel-foot robot as a center of circle and a distance from a foot end positioning point of any one leg to the center of mass as a radius; the foot end of each leg of the parallel wheel-foot robot is controlled to rotate an angle along the rotating path in sequence according to a certain rule, the positioning points of the foot ends of the remaining three legs are kept unchanged while the foot end of each leg rotates, and the four legs are controlled to synchronously rotate corresponding angles in opposite directions at the positioning points of the robot body.
And the switching module 203 is used for switching the gaits according to the walking direction and the walking posture of the parallel wheel-foot robot based on the straight intermittent gaits and the rotating gaits.
Specifically, the switching module 203 is further configured to perform walking switching of different types of the straight walking intermittent gait according to the walking direction of the parallel wheel-foot robot; and carrying out walking switching between the straight walking intermittent gait and the rotating gait according to the walking posture of the parallel wheel-foot robot.
In the embodiment of the invention, aiming at the characteristics of more complex control system and slower leg movement of the parallel wheel-foot robot, a proper gait walking control strategy and a gait conversion strategy are planned for the parallel wheel-foot robot, and through the combination of different gait strategies, the movement control performance of the parallel wheel-foot robot is greatly improved, and the overall movement stability is ensured. Aiming at the aspect of load feasibility, the pitch angle and the roll angle of the trunk of the parallel wheel-foot robot in the motion process are ensured to be within controllable amplitude, and the load-bearing forward stability is improved.
Those skilled in the art will appreciate that all or part of the steps in the methods of the above embodiments may be implemented by associated hardware instructed by a program, which may be stored in a computer-readable storage medium, and the storage medium may include: a Read Only Memory (ROM), a Random Access Memory (RAM), a magnetic or optical disk, or the like.
In addition, the above detailed description is given to the method and system for switching the omnibearing gait of the parallel wheel-foot robot provided by the embodiment of the present invention, and a specific embodiment should be adopted herein to explain the principle and the implementation manner of the present invention, and the description of the above embodiment is only used to help understanding the method and the core idea of the present invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, there may be variations in the specific embodiments and the application scope, and in summary, the content of the present specification should not be construed as a limitation to the present invention.
Claims (10)
1. An omnibearing gait switching method of a parallel wheel-foot robot is characterized by comprising the following steps:
establishing a kinematic model of the parallel wheel-foot robot;
planning a straight walking intermittent gait and a rotating gait of the parallel wheel-foot robot based on the kinematics model by taking the single-leg working space constraint and the walking stability constraint as consideration conditions;
and switching the gaits according to the walking direction and the walking posture of the parallel wheel-foot robot based on the straight walking intermittent gaits and the rotating gaits.
2. The omni-directional gait switching method according to claim 1, wherein the establishing of the kinematics model of the parallel-type wheel-legged robot comprises:
determining the position of the mass center of the parallel wheel-foot robot;
setting a positioning point of each leg in the four legs of the parallel wheel-foot robot on the robot body and a positioning point of the foot end of each leg;
the working space of each leg is set by taking the foot end positioning point of each leg as the center.
3. The omni-directional gait switch method according to claim 2, characterized in that the planning of the straight walking intermittent gait of the parallel-type wheel-legged robot comprises:
the foot end of each leg of the parallel wheel-foot robot is controlled to advance forwards along the same axial direction in sequence according to a certain rule, and the positioning points of the foot ends of the other three legs and the positioning points of the four legs on the robot body are kept unchanged while the foot end of each leg advances.
4. The omni-directional gait switch method according to claim 2, characterized in that the planning of the rotational gait of the parallel-type biped robot comprises:
the center of mass of the parallel wheel-foot robot is used as the center of a circle, the distance from a foot end positioning point of any leg to the center of mass is used as the radius, and the rotating path of the parallel wheel-foot robot is specified;
the foot end of each leg of the parallel wheel-foot robot is controlled to rotate an angle along the rotating path in sequence according to a certain rule, the positioning points of the foot ends of the remaining three legs are kept unchanged while the foot end of each leg rotates, and the four legs are controlled to synchronously rotate corresponding angles in opposite directions at the positioning points of the robot body.
5. The omni-directional gait switch method according to claims 3 to 4, characterized in that the switching of gait according to the walking direction and the walking posture of the parallel wheel-foot robot comprises:
carrying out walking switching among the straight walking intermittent gaits according to the walking direction of the parallel wheel-foot robot;
and carrying out walking switching between the straight walking intermittent gait and the rotating gait according to the walking posture of the parallel wheel-foot robot.
6. An all-round gait switched systems of parallel wheel-foot robot, characterized in that the system comprises:
the establishing module is used for establishing a kinematic model of the parallel wheel-foot robot;
the planning module is used for planning the straight walking intermittent gait and the rotating gait of the parallel wheel-foot robot by taking the single-leg working space constraint and the walking stability constraint as consideration conditions based on the kinematics model;
and the switching module is used for switching the gaits according to the walking direction and the walking posture of the parallel wheel-foot robot based on the straight walking intermittent gaits and the rotating gaits.
7. The omni-directional gait switch system according to claim 6,
the establishing module is also used for determining the position of the mass center of the parallel wheel-foot robot; setting a positioning point of each leg in the four legs of the parallel wheel-foot robot on the robot body and a positioning point of the foot end of each leg; the working space of each leg is set by taking the foot end positioning point of each leg as the center.
8. The omni-directional gait switch system according to claim 7,
the planning module is also used for controlling the foot end of each leg of the parallel wheel-foot robot to advance forwards along the same axial direction in sequence according to a certain rule, and keeping the positioning points of the foot ends of the other three legs and the positioning points of the four legs on the robot body unchanged while advancing at the foot end of each leg.
9. The omni-directional gait switch system according to claim 7,
the planning module is also used for defining a rotating path of the parallel wheel-foot robot by taking the center of mass of the parallel wheel-foot robot as the center of a circle and taking the distance from the foot end positioning point of any leg to the center of mass as the radius; the foot end of each leg of the parallel wheel-foot robot is controlled to rotate an angle along the rotating path in sequence according to a certain rule, the positioning points of the foot ends of the remaining three legs are kept unchanged while the foot end of each leg rotates, and the four legs are controlled to synchronously rotate corresponding angles in opposite directions at the positioning points of the robot body.
10. The omni-directional gait switch system according to claims 8 to 9, characterized in that,
the switching module is also used for switching the walking between the straight walking and intermittent gait according to the walking direction of the parallel wheel-foot robot; and carrying out walking switching between the straight walking intermittent gait and the rotating gait according to the walking posture of the parallel wheel-foot robot.
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