CN114852209A - Wheel-leg combined hexapod robot with sliding function and control method thereof - Google Patents
Wheel-leg combined hexapod robot with sliding function and control method thereof Download PDFInfo
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Abstract
The invention provides a wheel-leg combined hexapod robot with a sliding function and a control method thereof, wherein the robot comprises a robot body, wherein the rear end of the lower side of the robot body is provided with a directional wheel, and the front end of the lower side of the robot body is provided with a universal wheel; the directional wheel is used for driving the robot body to slide linearly under the action of the pedaling force of the rear legs of the hexapod robot; the universal wheels are used for driving the robot body to steer and slide under the action of pedaling the middle leg of the hexapod robot; according to the invention, the directional wheels and the universal wheels are arranged on the lower side of the robot body, the control of linear sliding and steering sliding is realized by controlling the suspension and the ground pedaling actions of different robot legs, the purpose of flexible combination between the wheel legs is achieved, the sliding function is realized on the basis of not increasing a driving system and a control system in a wheel type mode, the adaptability of the foot type robot to complex terrains is reserved, and meanwhile, the energy consumption of the foot type robot in the motion on a flat ground is reduced.
Description
Technical Field
The invention belongs to the technical field of robot control, and particularly relates to a wheel-leg combined hexapod robot with a sliding function and a control method thereof.
Background
The wheel type mobile robot is widely applied to daily life due to the characteristics of convenient control, simple structure and the like. But the wheel type robot is limited by the characteristics of wheel type movement, and the requirements of the wheel type robot on the terrain are high. Compared with the foot-type robot, the foot-type robot has stronger adaptability to unstructured terrain due to the characteristic of discrete foot-falling points of the foot-type robot in leg-foot type movement. However, the control method of the foot robot is complicated and high in energy consumption.
In order to improve the adaptability of the wheeled robot to a complex environment, most of research focuses on improving the structure of the wheeled robot or optimizing a trajectory tracking algorithm of the wheeled robot. For example, a control algorithm of the track tracking of the wheeled robot is improved, and the structure of the wheeled robot is optimized, so that the adaptability of the wheeled robot to the environment is improved. In order to optimize the energy consumption of the legged robot, a method for optimizing the structure of the legged robot or optimizing the motion state of the legged robot is mostly adopted. For example, the high-power-density motor is adopted to reduce the inertia of leg movement, optimize the gait control method of the robot and reduce the energy consumption of the robot.
The inventor finds that although the conventional wheel-leg combined hexapod machine can realize the switching between the wheel type sliding mode and the foot type walking mode, the two modes are simply combined, the mode switching and the walking control are independently performed, the flexible combination between the wheel legs is not realized, and simultaneously, an additional power system and a control system are required to be added on the basis of the foot type robot to match the sliding action in the wheel type mode.
Disclosure of Invention
The invention provides a wheel-leg combined hexapod robot with a sliding function and a control method thereof, aiming at solving the problems, the invention designs a novel robot structure, provides a control method for sliding of leg driving wheels on the basis of the novel robot structure, realizes flexible combination of wheel legs, realizes the sliding function on the basis of not increasing a driving system and a control system in a wheel type mode, reserves the adaptability of the foot robot to complex terrains, and simultaneously reduces the energy consumption of the foot robot in plane motion.
In order to achieve the above object, in a first aspect, the present invention provides a wheel-leg combined hexapod robot having a sliding function, which adopts the following technical solution:
the wheel-leg combined hexapod robot with the sliding function comprises a robot body, wherein the rear end of the lower side of the robot body is provided with a directional wheel, and the front end of the lower side of the robot body is provided with a universal wheel;
the directional wheel is used for driving the robot body to slide linearly under the action of the pedaling force of the rear legs of the hexapod robot; the universal wheels are used for driving the robot body to steer and slide under the action of the middle leg of the hexapod robot kicking the ground.
Furthermore, the front leg, the middle leg and the back leg of the hexapod robot respectively comprise joints, thighs and shanks which are connected through the joints; the middle leg has four degrees of freedom.
Furthermore, when the rear legs of the hexapod robot enter a motion state, other legs are in a suspension state, the rear legs kick the ground to apply forward force to the directional wheel, and the hexapod robot slides forwards or backwards under the action of the ground kicking force of the rear legs; when the middle leg on one side of the hexapod robot enters a motion state, other legs are in a suspension state, the middle leg on one side pedals the ground, and the universal wheel turns to the other side under the action of the ground pedaling force.
In order to achieve the above object, in a second aspect, the present invention further provides a wheel-leg combined hexapod robot control method with a sliding function, which adopts the following technical solution:
a control method of a wheel-leg combined hexapod robot having a sliding function, which adopts the wheel-leg combined hexapod robot having a sliding function as described in the first aspect; the method comprises the following steps:
the leg in the suspension state keeps the initial state still, and the leg in the motion state plans the foot end track based on a time state machine; and performing joint motor servo control on the foot end track based on a position control method.
Furthermore, when the six-legged robot slides forwards and backwards, the rear legs of the six-legged robot enter a motion state, and other legs are in a suspension state; dividing the motion state into a support phase and a swing phase based on a time state machine; respectively planning the tracks of the swing phase and the support phase, then solving the corresponding joint angle through forward and inverse kinematics, and controlling the joint motor angle;
when the robot turns right or left, the robot enters the motion state corresponding to the middle leg on the right side or the left side, and other legs keep the suspension state; and then the motor angle is controlled by means of kinematics by planning the motion trail of the hexapod robot.
Further, planning a swing phase track and a support phase track of the foot end of the hexapod robot; the mapping between the foot end track and the angle of the joint motor is established by a DH parameter method, and the control of the motion of the hexapod robot is realized by means of the control of the joint motor.
Further, planning the track of the swing phase by utilizing a cubic curve and planning the track of the support phase by utilizing a straight line for the direction of the x axis; for the y-axis direction, the initial position is maintained; and planning the swing track by using a cosine function in the z-axis direction, and adopting a constant value for the supporting phase leg part.
Further, when joint motor servo control is carried out on the foot end track, the angle of the joint motor is calculated according to a preset kinematics model, and the motion control of the legs of the hexapod robot is realized;
when a kinematic model is established, a trunk coordinate system, a leg coordinate system and a foot end coordinate system are respectively established; in the trunk coordinate system, the coordinate system is fixed on the trunk of the hexapod robot, the origin is located at the center of mass of the trunk of the hexapod robot, and the directions of three coordinate axes are respectively the right front of the trunk, the side of the hexapod robot and the direction vertical to the trunk; the leg coordinate system is fixed on a side swing joint of the hexapod robot, the origin is located at the mass center of the side swing joint of the hexapod robot, and the directions of three coordinate axes are respectively in the right front of a trunk, the side of the hexapod robot and the direction vertical to the side swing joint; the foot end coordinate system is fixed on the leg foot end of the hexapod robot, the origin is located in the center of the leg foot end of the hexapod robot, and the directions of the three coordinate axes are the same as the directions specified by a DH parameter method.
Further, the foot end position and the leg joint variables of the hexapod robot satisfy: the conversion from the space position of the joint of the hexapod robot to the position of the foot end is realized by means of forward kinematics, and the conversion from the position of the foot end of the hexapod robot to the joint angle is realized by means of inverse kinematics.
Further, by means of the inertia of the hexapod robot, the sliding motion of the robot on a flat terrain is realized.
Compared with the prior art, the invention has the following beneficial effects:
1. according to the invention, the directional wheels and the universal wheels are arranged on the lower side of the robot body, the control of linear sliding and steering sliding is realized by controlling the suspension and the ground pedaling actions of different robot legs, the purpose of flexible combination between the wheel legs is achieved, the sliding function is realized on the basis of not increasing a driving system and a control system in a wheel type mode, the adaptability of the foot type robot to complex terrains is reserved, and meanwhile, the energy consumption of the foot type robot in the motion on a flat ground is reduced.
2. The invention realizes the sliding control of the hexapod robot on the flat ground based on the position control method; determining whether the hexapod robot is in a motion cycle or in a holding state to slide by receiving an instruction; simplifying a hexapod robot model by means of forward and inverse kinematics in a motion period, and then completing switching between a swing phase and a support phase of the hexapod robot by planning a motion track of a foot end and based on a time state machine, so that the robot slides along a straight line; and finally, by means of the idea of oscillation synthesis, the lateral motion and the linear motion are superposed to realize the steering operation of the sliding of the robot.
Drawings
The accompanying drawings, which form a part hereof, are included to provide a further understanding of the present embodiments, and are incorporated in and constitute a part of this specification, illustrate exemplary embodiments of the present embodiments and together with the description serve to explain the present embodiments without unduly limiting the present embodiments.
FIG. 1 is a schematic structural view of example 1 of the present invention;
FIG. 2 is a control block diagram of embodiment 1 of the present invention;
FIG. 3 is a schematic diagram illustrating the coordinate system definition in example 1 of the present invention;
FIG. 4 is a graph showing the effect of the test of the linear sliding motion in embodiment 3 of the present invention;
FIG. 5 is a graph showing the effect of the lateral sliding movement test according to embodiment 3 of the present invention;
FIG. 6 is a diagram showing the effect of the braking exercise test according to embodiment 3 of the present invention;
the robot comprises a robot body 1, a robot body 2, a directional wheel 3 and a universal wheel.
The specific implementation mode is as follows:
the invention is further described with reference to the following figures and examples.
It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the disclosure. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.
Example 1:
in order to reduce the energy consumption of the system and maintain the adaptability of the robot to complex terrains, the embodiment provides a wheel-leg combined hexapod robot with a sliding function, which comprises a robot body, wherein a directional wheel is installed at the rear end of the lower side of the robot body, and a universal wheel is installed at the front end of the lower side of the robot body; the directional wheel is used for driving the robot body to slide linearly under the action of the pedaling force of the rear legs of the hexapod robot; the universal wheels are used for driving the robot body to steer and slide under the action of the middle leg of the hexapod robot kicking the ground. The embodiment provides a novel structure which can enable the hexapod robot to slide on flat terrain, and realizes the motion control of the hexapod robot sliding on the basis of the structure. As shown in fig. 2, the motion sequence of the hexapod robot is controlled by the command of the remote controller, and the motion trail of the foot end is planned based on the time state machine according to the motion target; and mapping the foot end track from the working space to the change of the motor joint angle in the joint space by means of forward and inverse kinematics, thereby realizing the sliding control of the robot on a flat terrain.
The hexapod robot structure designed by the embodiment is as follows:
for the design of a leg structure, six legs are symmetrically arranged on two sides of a robot body by taking the leg structure of a quadruped mammal in nature as a reference; the front leg, the middle leg and the backward leg of the hexapod robot at least comprise joints, thighs and calves which are connected through the joints; the middle leg has four degrees of freedom; by using the design idea of the redundant degree of freedom foot type robot for reference, the middle leg has four degrees of freedom, and the foot type robot can be further expanded into a foot-arm multiplexing type robot.
As shown in fig. 1, in order to realize the function of the robot sliding on a flat road; two directional wheels are arranged on the rear abdomen of the hexapod robot, and a universal wheel is arranged on the front abdomen of the robot; the direction of the hub is consistent with the advancing direction of the robot.
In one embodiment, a motion control method for driving a driven wheel to slide omnidirectionally by an active leg is provided on the basis of the hexapod robot structure, and the method specifically comprises the following steps:
s1, controlling the motion sequence of the robot by a remote controller;
the sliding motion of the hexapod robot is divided into linear sliding and steering sliding; by means of the idea of oscillation synthesis, the corresponding sliding track is synthesized by controlling leg movement.
Controlling a remote controller to send out a related instruction according to the expected sliding track of the robot; determining the motion state of each leg of the robot according to the corresponding control instruction of the remote controller; the leg in the suspension state keeps the initial state still, and the leg in the motion state plans the foot end track based on a time state machine; and then, performing joint motor servo control on the foot end track based on a position control method.
After a front-back sliding instruction is received, the left back leg and the right back leg of the robot enter a motion state at the same time, and the other legs are in a suspended state and keep an initial state; and dividing the motion state into a support phase and a swing phase based on a time state machine. And respectively planning the tracks of the support phase and the swing phase, solving the corresponding joint angle through forward and inverse kinematics, and controlling the joint motor angle to enable the robot to realize related functions.
Similarly, when the remote controller sends a right turn instruction, the robot enters a motion state corresponding to the middle leg on the right side, and other legs keep a suspension state; after the remote controller sends a left turn instruction, the robot enters a transportation state corresponding to the middle leg on the left side, and other legs keep a suspension state; and then the sliding operation of the robot is realized by planning the motion track of the robot and controlling the angle of the motor by means of kinematics.
S2, after the motion state is entered, planning a supporting phase and a swinging phase track expected by a foot end based on a time state machine according to parameters such as step height step length and the like;
planning a swing phase track and a support phase track of a foot end of the robot after receiving a motion instruction related to the remote controller; establishing mapping between a foot end track and a joint motor angle by a DH parameter method; the motion of the robot is controlled by controlling the joint motor; wherein the gait cycle is T, and the swing phase and the support phase have a period of T s And T c (ii) a On the basis, a track with continuous track, continuous speed and continuous support phase speed is designed.
For the X-axis direction, planning the track of the swing phase by using a cubic curve and planning the track of the support phase by using a straight line, which comprises the following steps:
wherein x is s Representing the locus of the oscillatory phase, x c Representing the trajectory of the supporting phase, S representing the amplitude of oscillation within the movement period, t k Is the time the current cycle has elapsed.
For the y-axis direction, its initial position is maintained:
planning a swing track by using a cosine function in the Z-axis direction, and adopting a constant value for a supporting phase leg part; the expression is as follows:
wherein z is s Representing the locus of the oscillatory phase, z c Representing the trajectory of the supporting phase, H representing the height of the step in the movement cycle, t k Is the time the current cycle has elapsed.
S3, establishing a kinematics model of the hexapod robot, solving the joint motor angle by means of the kinematics model, realizing motion control of the legs of the robot, and controlling the sliding of the driving wheels by controlling the leg motion; the specific process is as follows:
s3.1, establishing a coordinate system:
torso coordinate system Σ B : the coordinate system is fixed on the trunk of the robot, the origin is located at the center of mass of the trunk of the robot, X B Pointing right ahead of the trunk, Y B Pointing to the left of the robot, Z B Perpendicular to the torso and up;
coordinate system sigma of leg 0 : the coordinate system is fixed on the side swing joint of the robot, the origin is positioned at the center of mass, X, of the side swing joint of the leg of the robot 0 Pointing right ahead of the trunk, Y 0 Pointing to the left of the robot, Z 0 Is vertical to the side swing joint and faces upwards;
foot end coordinate system sigma E : the coordinate system is fixed on the leg foot end of the robot, the origin is positioned in the center of the leg foot end of the robot, and X is e 、Y e 、Z e The direction is the same as the direction specified by the DH parameter method;
s3.2, setting the initial position of the foot end as the basis of inputting and planning the trajectory of the foot end based on the kinematic equation of the robot:
solving the motion of the robot according to the established coordinate system by using a DH parameter methodAnd (5) learning the model. For a robot model, the relationship between joint space and task space can be described by a Jacobian matrix. Foot end position of hexapod robot B p TOE With the leg joint variable q satisfying B p TOE Fk (q) and IK (IK), (IK) and (k) are given as follows B p TOE ). Wherein FK represents forward kinematics, and the conversion of the space position of the joint of the robot to the position of the foot end is realized by means of the forward kinematics; IK represents inverse kinematics for achieving the robot foot position to joint angle translation.
S4, controlling the motion of the abdomen wheels by controlling the motion of the legs; by means of the inertia of the robot movement, the sliding movement of the robot on a flat terrain is realized.
When the rear legs of the hexapod robot enter a motion state, other legs are in a suspended state, the rear legs kick the ground, a forward force is applied to the abdominal wheel, no force is applied to the wheels, the wheels slide forwards or backwards under the action of the rear legs kicking the ground, and the robot slides for a certain distance along a straight line under the action of inertia; when the right leg of the robot enters a motion state, other legs are in a suspension state, the middle leg on the right side pedals the ground, the universal wheel turns to the left under the action of the pedaling ground force, and the directional wheel slides forwards under the action of force; under the two actions, the robot slides leftwards to turn; similarly, the left middle leg kicks the ground, so that the robot slides to the right.
And planning the motion track of each leg through a time state machine, and solving the joint angle corresponding to the track by means of forward and inverse kinematics. The leg movement is controlled by controlling the angle of the joint motor, the movement of the wheels is further driven, and the sliding movement of the robot on a flat terrain is realized.
In the embodiment, by taking advantage of the legged robot and the wheeled robot, the directional wheels and the universal wheels are arranged on the abdomen of the legged robot; on the basis of the structure, the robot can control the motion of abdomen driving wheels by means of leg motion, and further realize the sliding motion of the robot; the robot with the complex terrain can adopt foot type motion to keep the adaptability of the robot to the complex terrain; meanwhile, the energy consumption of the legged robot on the flat terrain can be reduced by driving the driving legs to drive the driven wheels to slide on the relatively flat terrain.
The embodiment realizes the sliding control of the hexapod robot on the flat ground based on a position control method; sending a control command according to the expected motion state of the robot; determining the motion time sequence of the foot end of the robot according to the control instruction; and determining the trajectories of the support phase and the swing phase for the foot end in the motion period based on a time state machine. Controlling the motion of the motor according to the foot end track; and finally, overlapping the motion of the lateral legs and the motion of the rear legs of the robot by means of the idea of oscillation synthesis to realize the control of the omnibearing sliding of the robot.
Example 2:
the embodiment provides a control method of a wheel-leg combined hexapod robot with a sliding function, which adopts the wheel-leg combined hexapod robot with the sliding function as described in the embodiment 1; firstly, determining the motion state of the leg of the robot according to the instruction of a remote controller; in a gait cycle, relevant parameters of a motion track are set according to step length and step height parameters, a swing phase of the robot is planned based on a time state machine, an expected foot end position of the phase is supported, and after the foot end position is obtained, a motor joint angle is controlled according to a kinematics model, so that the servo of the motion track of the leg is realized. The abdomen wheel is driven to complete the expected movement through controlling the leg movement; and finally, realizing the sliding operation of the robot by means of inertia.
The method comprises the steps of sending relevant instructions of advancing and sliding through a remote controller, determining the motion state of legs, dividing the specific motion state control into the control of a support phase and a swing phase, and determining the foot end track of gait motion by means of the sliding step length of the robot.
After the robot is switched to a sliding state, the six legs of the robot are kept in an initial state, when the remote controller sends a forward command, the rear legs of the robot enter a motion period, and the motion trail of the foot end of the robot is planned based on the input step length step height. And controlling the joint angle of the motor through the motion trail. After the motion period is finished, the rear leg enters a suspended state, the initial motor angle is kept still, the robot slides under the action of inertia of the driven wheel, and similarly, after a left turn instruction of the robot is received, the right middle leg corresponding to the robot moves. And after a right turn instruction of the robot is received, the left middle leg corresponding to the robot moves.
The motion control of the leg can be decomposed into the control of a support phase and the control of a swing phase, and the control of the two states adopts a control method based on foot end trajectory planning. Firstly, the motion trail of the foot end is planned, then the joint angle is calculated by using inverse kinematics, and the leg motion can be controlled by the leg motor servo motor joint angle. The planned track has the characteristics of continuous track, continuous speed and constant support phase speed.
The period of the leg movement is T, wherein the periods of the swing phase and the support phase are T respectively s 、T c The forward and steering motions of the robot are controlled through the supporting phase. The coordinates of the starting point of the support phase are (x) c0 (0),y c0 (0),z c0 (0) Supporting phase at t) k The trajectory of the time of day is approximately:
wherein, S represents the swing amplitude in the motion period, and the sliding distance of the robot can be controlled by adjusting the swing amplitude.
The swing phase track uses a cubic curve to plan the motion track in the air by controlling the foot falling point of the quadruped robot, and keeps the continuity of the track and the speed when switching with the support phase; when the robot is in an initial state, the robot keeps a suspended state so as to facilitate the subsequent sliding of the robot; after the track of the support phase is finished, the leg part needs to swing to an initial position in order to enable the robot to slide by utilizing inertia; the swing phase trajectory is therefore as follows:
the first quarter period of the whole movement period is a swing phase; assuming that the initial point of the robot swing phase has a foot end coordinate of (x) s (0),y s (0),z s (0) The foot end trajectory is as follows:
the latter quarter period of the whole motion period is a swinging phase, and the swinging phase swings to the initial position of the robot from the supporting point of the robot; let the initial coordinates of the support points be as follows (x) ce (3T/4),y ce (3T/4),z ce (3T/4)), then the foot end trajectory is as follows:
s represents the swing amplitude in the motion period, the swing amplitude is adjusted and can be matched with the support, the swing track is continuous, and the speed is continuous; h represents the step height of the robot swing.
The specific trajectory equation at the foot end is:
determining whether each leg is in a swinging phase or a supporting phase through the combination of a time state machine, and then moving according to a planned track; the joint angle is solved through inverse kinematics, so that the motor serves the joint angle, and the motion of the robot is controlled.
Establishing a robot simplified model based on a kinematic equation of the robot, and settling a motor joint angle by using inverse kinematics;
establishing a coordinate system:
torso coordinate system Σ B : the coordinate system is fixed on the trunk of the robot, the origin is located at the center of mass of the trunk of the robot, X B Pointing to the trunkStraight ahead, Y B Pointing to the left of the robot, Z B Perpendicular to the torso and up;
coordinate system sigma of leg 0 : the coordinate system is fixed on the side swing joint of the robot, the origin is positioned at the center of mass, X, of the side swing joint of the leg of the robot 0 Pointing right ahead of the trunk, Y 0 Pointing to the left of the robot, Z 0 Is vertical to the side swing joint and faces upwards;
foot end coordinate system sigma E : the coordinate system is fixed on the leg and foot end of the robot, the origin is positioned in the center of the leg and foot end of the robot, and X is e 、Y e 、Z e The direction is the same as the direction specified by the DH parameter method;
solving the joint angle of the robot based on the inverse kinematics model of the leg:
and solving the positive kinematics of the robot according to the established coordinate system by using a DH parameter method. The hind legs are leg models composed of 3 degrees of freedom, and the relation between the foot end position and the joint angle can be expressed by means of positive and negative kinematics. Forward and inverse kinematics can be simply written as follows:
B p TOE ＝FK(q)
q＝IK( B p TOE )
where q represents the joint angle, for the hind leg: q ═ θ 1 θ 2 θ 3 ] T For the middle leg: q ═ θ 1 θ 2 θ 3 θ 4 ] T ； B p TOE The foot end position in the leg coordinate system is indicated. FK represents positive kinematics, and realizes the mapping of joint angles and foot end positions; IK represents inverse kinematics, implementing a mapping of the foot end position to joint angle.
The driving legs move to drive the driven wheels to slide, so that the sliding motion of the robot is realized.
When the rear legs of the hexapod robot enter a motion state, other legs are in a suspended state, the rear legs kick the ground, a forward force is applied to the abdominal wheel, no force is applied to the wheels, the wheels slide forwards or backwards under the action of the rear legs kicking the ground, and the robot slides for a certain distance along a straight line under the action of inertia; when the right leg of the robot enters a motion state, other legs are in a suspension state, the middle leg on the right side pedals the ground, the universal wheel turns to the left under the action of the pedaling ground force, and the directional wheel slides forwards under the action of the force; under the two actions, the robot slides leftwards to turn; similarly, the left middle leg kicks the ground, so that the robot slides to the right.
The embodiment uses the advantages of wheel type motion for reference, a group of pulleys are placed on the abdomen of the hexapod robot, two directional wheels which are placed side by side with the back abdomen can slide under the inertia of the robot motion, and the universal wheels which are placed on the front abdomen of the robot can control the sliding direction of the robot under the control of the motion of related legs, so that the sliding motion of the robot on a flat ground is realized; the structure expands the motion form of the hexapod robot, so that the robot can slide on a flat road surface, and the energy consumption of the traditional foot type robot in plane motion is reduced.
The embodiment realizes sliding control on the flat ground of the hexapod robot based on a position control method, determines whether the robot slides in a motion period or a holding state by controlling and sending a related instruction through a remote controller, simplifies a robot model by means of forward and inverse kinematics in the motion period, then completes switching between a swing phase and a support phase of the robot by planning a motion track of a foot end and based on a time state machine, thereby realizing the operation that the robot slides along a straight line, and finally superposes lateral motion and the straight line motion by means of an oscillation synthesis idea, thereby realizing the steering operation that the robot slides.
Example 3:
to verify the feasibility of examples 1 and 2, this example was subjected to straight sliding, lateral sliding and braking tests by a hexapod robot entity, and the results are shown in fig. 4, 5 and 6.
The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and those skilled in the art can make various modifications and variations. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present embodiment should be included in the protection scope of the present embodiment.
Claims (10)
1. The wheel-leg combined hexapod robot with the sliding function comprises a robot body and is characterized in that a directional wheel is mounted at the rear end of the lower side of the robot body, and a universal wheel is mounted at the front end of the lower side of the robot body;
the directional wheel is used for driving the robot body to slide linearly under the action of the pedaling force of the rear legs of the hexapod robot; the universal wheels are used for driving the robot body to steer and slide under the action of the middle leg of the hexapod robot kicking the ground.
2. The wheel-leg combined hexapod robot with a skating function as claimed in claim 1, wherein the front leg, the middle leg and the back leg of the hexapod robot each include a joint, and an upper leg and a lower leg connected by the joint; the middle leg has four degrees of freedom.
3. The wheel-leg combined hexapod robot with a gliding function as claimed in claim 1, wherein when the back leg of the hexapod robot enters a motion state, other legs are in a suspension state, the back leg pedals the ground to apply a forward force to the directional wheel, and the back leg pedals the ground to glide forwards or backwards; when the middle leg on one side of the hexapod robot enters a motion state, other legs are in a suspension state, the middle leg on one side pedals the ground, and the universal wheel turns to the other side under the action of the ground pedaling force.
4. A control method of a wheel-leg combined hexapod robot having a sliding function, characterized in that the wheel-leg combined hexapod robot having the sliding function according to any one of claims 1 to 3 is used; the method comprises the following steps:
the leg in the suspension state keeps the initial state still, and the leg in the motion state plans the foot end track based on a time state machine; and performing joint motor servo control on the foot end track based on a position control method.
5. The control method of the wheel-leg combined hexapod robot with the gliding function as claimed in claim 4, wherein when the front and rear gliding is performed, the rear leg of the hexapod robot enters a motion state and other legs are in a suspension state; dividing the motion state into a support phase and a swing phase based on a time state machine; respectively planning the tracks of the swing phase and the support phase, then solving the corresponding joint angle through forward and inverse kinematics, and controlling the joint motor angle;
when the robot turns right or left, the robot enters the motion state corresponding to the middle leg on the right side or the left side, and other legs keep the suspension state; and then the motor angle is controlled by means of kinematics by planning the motion trail of the hexapod robot.
6. The control method of a wheel-leg combined hexapod robot with a skating function as claimed in claim 5, wherein a swing phase trajectory and a support phase trajectory of a foot end of the hexapod robot are planned; the mapping between the foot end track and the angle of the joint motor is established by a DH parameter method, and the control of the motion of the hexapod robot is realized by means of the control of the joint motor.
7. The control method of a wheel-leg combined hexapod robot with a gliding function as claimed in claim 6, wherein for the x-axis direction, a trajectory of a swing phase is planned using a cubic curve, and a trajectory of a support phase is planned using a straight line; for the y-axis direction, the initial position is maintained; and planning the swing track by using a cosine function in the z-axis direction, and adopting a constant value for the supporting phase leg part.
8. The control method of a wheel-leg combined hexapod robot with a skating function as claimed in claim 4 or 6, wherein when joint motor servo-controlling is performed on the foot end trajectory, the joint motor angle is calculated according to a preset kinematic model to realize the motion control of the hexapod robot leg;
when a kinematic model is established, a trunk coordinate system, a leg coordinate system and a foot end coordinate system are respectively established; in the trunk coordinate system, the coordinate system is fixed on the trunk of the hexapod robot, the origin is located at the center of mass of the trunk of the hexapod robot, and the directions of three coordinate axes are respectively the right front of the trunk, the side of the hexapod robot and the direction vertical to the trunk; the leg coordinate system is fixed on a side swing joint of the hexapod robot, the origin is located at the mass center of the side swing joint of the hexapod robot, and the directions of three coordinate axes are respectively in the right front of a trunk, the side of the hexapod robot and the direction vertical to the side swing joint; the foot end coordinate system is fixed on the leg foot end of the hexapod robot, the origin is located in the center of the leg foot end of the hexapod robot, and the directions of the three coordinate axes are the same as the directions specified by a DH parameter method.
9. The control method of a wheel-leg combined hexapod robot having a coasting function as claimed in claim 8, wherein the foot end position and leg joint variables of the hexapod robot satisfy: the conversion from the space position of the joint of the hexapod robot to the position of the foot end is realized by means of forward kinematics, and the conversion from the position of the foot end of the hexapod robot to the joint angle is realized by means of inverse kinematics.
10. The control method of a wheel-leg combined hexapod robot having a coasting function as claimed in claim 4, wherein the coasting movement of the robot on a flat terrain is achieved by means of inertia of the hexapod robot movement.
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