CN114384918A - Diagonal gait compliance control method of four-footed robot based on drop foot point adjustment - Google Patents
Diagonal gait compliance control method of four-footed robot based on drop foot point adjustment Download PDFInfo
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Abstract
A method for controlling diagonal gait compliance of a quadruped robot based on foot drop point adjustment relates to an electrically driven quadruped robot. The method comprises the following steps: establishing a simplified rigid body model of the quadruped robot; according to the simplified rigid body model, combining sensor data such as a motor encoder, a foot sole laser distance sensor, a joint force sensor, an IMU and the like to calculate and obtain a joint angle, a ground contact signal, a hip motion state and a body mass center posture; adjusting foot falling points and planning a foot end track with self-adaptive leg lifting height; designing starting posture and walking transition, and carrying out diagonal sprint gait planning; designing a state machine for switching the diagonal sprint gait; and establishing an impedance controller and a virtual model controller for the motion of the quadruped robot. The electric drive quadruped robot is flexibly and stably walked by establishing a control method for controlling the diagonal running gait of the quadruped robot to be flexible and walk based on the adjustment of the foot drop point.
Description
Technical Field
The invention relates to an electrically-driven quadruped robot, in particular to a method for controlling diagonal gait compliance of the quadruped robot based on foot drop point adjustment.
Background
Robotics is a cross discipline related to the disciplines of mechanics, electronics, computer science, artificial intelligence, and the like. The robot can help people to do work in some aspects of danger, machine repetition and the like. The research robot technology has high application value and social value.
Compared with a wheeled and tracked robot, the legged robot can flexibly walk in uneven and unstructured environments, and has better terrain adaptability and flexible motion performance. Based on flexible movement capability, the foot type robot can participate in work tasks of complex working conditions, such as exploration of field unknown environment load instruments, transportation of dangerous environment rescue substances after disasters (such as earthquakes, fires and the like), long-time field marching transportation, nuclear power station operation (such as nuclear leakage) and the like to finish application of special working conditions.
The foot robots are divided according to the number of feet, and generally comprise two-foot, four-foot, six-foot and other foot robots. Compared with a biped robot, the quadruped robot has more flexible movement capability; compared with a hexapod robot, the quadruped robot is simpler in mechanical structure, control algorithm and the like. In conclusion, the four-footed robot can realize flexible movement capability on the basis of a simpler mechanical structure and a control algorithm.
The gait of the quadruped robot means that the foot end trajectory planning is performed in a time sequence so that the quadruped robot can move rhythmically. The movement of the quadruped robot is divided into a support phase and a swing phase, and the gait can be approximately Crawl (Crawl) gait, contralateral (Pace) gait, diagonal sprint (Trot) gait, jump (Bound) gait, sprint (Gallop) gait and the like according to the phase difference between each leg.
The virtual model control is that the spring damping model is arranged on the mass center, the foot end and the like and is connected with an external action point, so that the virtual force to the quadruped robot is generated. The virtual force is converted into joint torque through a certain mapping relation, and then the control of the quadruped robot is achieved.
The compliance control is divided into passive compliance control and active compliance control. The passive compliance control is that a body (such as a foot end) of the quadruped robot is provided with a spring and the like for damping and buffering, so that external impact is reduced and compliance performance is realized. The active compliance control is to realize compliance performance through a control algorithm. Compared with passive compliance control, active compliance control has the advantages of simple mechanical structure, high control flexibility and the like.
At present, an electrically-driven four-footed robot based on drop foot point adjustment mainly adopts a static planning method in the aspect of foot end trajectory planning, and cannot adapt to the terrain well; in the aspect of diagonal sprint gait planning, the existing research on starting posture and walking transition is deficient, and the stability of the quadruped robot during starting is not facilitated; in the aspect of diagonal running gait state transition, only the state transition between two pairs of virtual legs exists, but the situation that one leg of one pair of virtual legs lands first and the other leg lands later may occur actually; in the aspect of generating and converting virtual force and virtual moment, the general method is to generate the virtual force and virtual moment with six degrees of freedom at the position of a mass center and then convert the virtual force and virtual moment into each joint through a space mapping matrix and a Jacobian matrix, and the calculation complexity is high and the algorithm is complex.
Disclosure of Invention
The invention aims to provide a four-foot robot diagonal gait compliance control method based on foot drop point adjustment, which comprises rigid body modeling, posture acquisition, foot end trajectory planning, diagonal sprint gait planning, state machine design, an impedance controller and an improved virtual model controller, so as to realize more stable and compliant walking of the electrically driven four-foot robot on the basis of the diagonal sprint gait adjusted by the foot drop point.
The invention comprises the following steps:
1) establishing a simplified rigid body model of the quadruped robot;
2) according to the simplified rigid body model, combining sensor data such as a motor encoder, a foot sole laser distance sensor, a joint force sensor, an IMU and the like to calculate and obtain a joint angle, a ground contact signal, a hip motion state and a body mass center posture;
3) adjusting foot falling points and planning a foot end track with self-adaptive leg lifting height;
4) designing starting posture and walking transition, and carrying out diagonal sprint gait planning;
5) designing a state machine for switching the diagonal sprint gait;
6) and establishing an impedance controller and a virtual model controller for the motion of the quadruped robot.
In the step 1), the simplified rigid body model of the quadruped robot is established by establishing a world coordinate system, a body coordinate system and a joint coordinate system in space; for simplicity of modeling and control, the mass and the moment of inertia of the four legs are ignored, a simplified rigid body model of the quadruped robot is established, and a kinematic equation and a leg Jacobian matrix of the model are obtained.
In step 3), the specific steps of performing the foot end trajectory planning of the foot drop point adjustment and the leg raising height self-adaptation are as follows:
step 3.1, setting foot end trajectory equations in the x, y and z directions of the swing phase;
and 3.2, properly adjusting the leg lifting height of the foot end according to the terrain condition.
In the step 4), designing starting posture and walking transition, and carrying out diagonal sprint gait planning specifically comprises the following steps:
on the basis of stepping, the robot moves for a half gait cycle in a half step length, and then is switched into a full step length to carry out diagonal running motion, so that on one hand, the stable transition of the speed of the robot can be ensured, the sudden change of the speed of the robot cannot be caused, on the other hand, the position of a foot end relative to a hip joint can be ensured to be kept in a symmetrical state, and the stability of the motion is facilitated.
In step 5), the specific steps of designing the state machine for switching the diagonal sprint gait are as follows:
and 5.1, designing a state machine set for switching the diagonal sprint gait.
Step 5.2, combining the touchdown information of each leg to switch the diagonal running state; considering more actual grounding conditions, the switching method of the state machine comprises the sequential problem of swinging legs to land and a four-foot supporting phase for adjusting the posture of the machine body and improving the stability of the machine body.
In step 6), the specific implementation process of the impedance controller and the virtual model controller for establishing the motion of the quadruped robot is as follows:
step 6.1, dividing the state of each leg into a support phase and a swing phase;
step 6.2, designing an impedance controller for the leg in the swing phase;
step 6.3, for the leg in the supporting phase, a virtual spring damping model in three translation directions is assumed at the hip part of the leg to calculate virtual force, and a virtual spring damping model in three rotational degrees of freedom is assumed at the mass center to calculate virtual moment so as to convert the virtual force and the virtual moment into the virtual force and the virtual moment of the supporting leg; the virtual force of the hip is converted into three joint moments through a jacobian matrix of the leg.
Compared with the prior art, the invention has the following outstanding advantages and technical effects:
in the aspect of foot end trajectory planning, compared with the static planning method, the foot end trajectory planning method with the functions of foot drop point adjustment, leg lifting height and support phase time self-adaption is provided, so that the method can be better suitable for terrain and improves the motion stability.
In the aspect of diagonal sprint gait planning, the current research on starting posture and walking transition is deficient, and a starting mode is provided: on the basis of stepping, the robot moves for a half gait cycle in a half step length, and then is switched into a full step length to carry out diagonal running motion, so that on one hand, the stable transition of the speed of the robot can be ensured, the sudden change of the speed of the robot cannot be caused, on the other hand, the position of a foot end relative to a hip joint can be ensured to be kept in a symmetrical state, and the stability of the motion is facilitated.
In the aspect of diagonal sprint gait state switching, compared with the state switching between only two pairs of virtual legs, the state machine switching method based on the plantar touchdown signal is provided, and the possibility of more states is considered, considering that more complicated situations that one pair of virtual legs touches the ground first and the other virtual legs touch the ground later due to the terrain and the like can actually occur.
In addition, given enough quadruped supporting phase time, the method can be used for adjusting the attitude of the fuselage and improving the stability of the fuselage. Compared with the prior method that the virtual force and the virtual moment with six degrees of freedom are generally generated at the position of the mass center, the method that the virtual force and the virtual moment with six degrees of freedom are generated and converted at the aspect of generating and converting the virtual force and the virtual moment and then are converted into each joint through a space mapping matrix and a Jacobian matrix designs an impedance controller of a swing phase and a virtual model controller of a support phase, has lower calculation complexity and simple algorithm, and can flexibly and stably realize the motion of the quadruped robot.
Drawings
FIG. 1 is a schematic flow chart of an embodiment of the present invention.
Fig. 2 is a schematic view of the overall structure of the legged robot.
Fig. 3 is a state machine switching diagram.
Fig. 4 is a schematic diagram of an impedance control framework.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the following embodiments will be further described with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. On the contrary, the invention is intended to cover alternatives, modifications, equivalents and alternatives which may be included within the spirit and scope of the invention as defined by the appended claims. Furthermore, in the following detailed description of the present invention, certain specific details are set forth in order to provide a better understanding of the present invention. It will be apparent to one skilled in the art that the present invention may be practiced without these specific details.
Example 1
The implementation steps of this embodiment are shown in fig. 1:
step one, establishing a simplified rigid body model of the quadruped robot;
calculating to obtain joint angles, ground contact signals, hip motion states and body mass center postures according to the simplified rigid body model by combining sensor data such as a motor encoder, a foot sole laser distance sensor, a joint force sensor and an IMU;
step three, performing foot drop point adjustment and foot end trajectory planning of leg lifting height self-adaption;
designing starting posture and walking transition, and carrying out diagonal sprint gait planning;
designing a state machine for switching the diagonal jogging gait;
and step six, establishing an impedance controller and a virtual model controller of the quadruped robot.
The above steps are described in detail below.
Step one, establishing a simplified rigid body model of the quadruped robot, as shown in figure 2.
Specifically, a world coordinate system, a body coordinate system, and a joint coordinate system are established in space. For simplicity of modeling and control, the mass and moment of inertia of the four legs are ignored, since the leg mass is substantially negligible relative to the fuselage mass. And establishing a simplified rigid body model of the quadruped robot to obtain a kinematic equation, a leg Jacobian matrix and the like of the model.
And step two, calculating according to the simplified rigid body model and combining sensor data such as a motor encoder, a foot sole laser distance sensor, a joint force sensor, an IMU and the like to obtain a joint angle, a ground contact signal, a hip motion state and a body mass center posture.
Specifically, the motor encoder measures the joint angle θ of 12 jointsiAnd joint angular velocity
Wherein i belongs to {1, 2,. eta., 11, 12}, the sequence is left front leg, right back leg and left back leg, the internal sequence of each leg is hip joint, thigh joint and shank joint, for example, the hip joint angle of the right front leg is theta4(ii) a The laser distance sensor of sole measures the touchdown state of each leg, and a threshold value deltad is setfootMeasured value dfoot，iIs compared with a threshold value if dfoot，i≥ΔdfootWhen the sole is not in contact with the ground, dfoot，i＜ΔdfootThen, representing sole touchdown, wherein i belongs to {1, 2, 3, 4}, and the sequence is left front leg, right rear leg and left rear leg; the joint force sensor measures the moment tau at each leg jointjoint，ijWhereini e {1, 2, 3, 4}, j e {1, 2, 3}, e.g., τjoint，23Representing the shank joint moment of the right front leg; IMU measures the actual attitude angular velocity of the mass center of the body
And the actual acceleration in the three directions of xyz
Calculating hip motion state (x) by combining the data of the motor encoder and the IMU with positive leg kinematics and the likecoxa，ycoxa，zcoxa) And
and body centroid attitude (theta)pitch，θroll，θyaw)。
And step three, performing foot end trajectory planning of foot drop point adjustment and leg lifting height self-adaption. The method specifically comprises the following steps:
and 3.1, setting a foot end trajectory equation in the x direction, the y direction and the z direction of the swing phase.
Specifically, the method comprises the following steps: firstly, according to the body speed feedback obtained in the step two
Determining the position of a foot-falling point in the x and y directions
The step length S can be obtainedx＝xf-x0，Sy＝yf-y0Wherein x0，y0The position at the end of the periodic support phase of the previous step. Secondly, a foot end trajectory equation is determined through interpolation, and the interpolation equation can be a cycloid function, a trigonometric function polynomial, a high-order polynomial and the like. Based on the characteristics of zero impact in the x and y directions (the speed and the acceleration of the foot end relative to the hip joint are 0 when the swing leg touches the ground), the quintic polynomial x is selected as the interpolation polynomial axt5+bxt4+cxt3+dxt2+ext+fx，y＝ayt5+byt4+cyt3+dyt2+eyt+fy. And (4) solving the relevant parameters of the interpolation equation by combining position, speed and acceleration constraints. And finally, continuously iterating the foot end trajectory algorithm in each period, and realizing real-time control of the speed of the machine body based on the on-line adjustment of the foot falling point. Note that the appropriate motion period T and support phase time T are givenstIsopod end trajectory parameters, where projected support phase time TstNot a constant one, but equal to the actual support phase time fed back from the previous cycle.
And 3.2, properly adjusting the leg lifting height delta h of the foot end according to the terrain condition.
Specifically, first, the leg-raising height Δ h is determined0(ii) a Secondly, intuitively adjusting the height according to the fed-back posture of the airplane body; finally, the leg lifting height interval is limited to [ delta h [)max,Δhmin]。
And step four, designing starting posture and walking transition, and carrying out diagonal sprint gait planning. The method specifically comprises the following steps:
and 4.1, designing starting posture and walking transition.
First, with a planned foot tip height Δ h0Stepping in situ; secondly, the step length is half step length first on the basis of the step
Half gait cycle of exercise
And finally, switching to the full step S to perform diagonal sprint exercise. Therefore, on one hand, the stable transition of the speed of the machine body can be ensured, the sudden change of the speed of the machine body can not be caused, on the other hand, the position of the foot end relative to the hip joint can be ensured to be kept in a symmetrical state, and the stability of movement is facilitated.
And 4.2, performing diagonal sprint gait planning.
The left front leg and the right rear leg are a pair of virtual legs, and the right front leg and the left rear leg are a pair of virtual legs. The phase difference phi of the two pairs of virtual legs is planned to be 0.5, and the duty ratio (percentage of the whole gait cycle of the support phase station) is planned to be 55 percent, so that the quadruped robot is ensured to have the state of the quadruped support phase in the motion process, and the motion stability is enhanced. The initial swing position of each leg can be finely adjusted according to the specific posture of the quadruped robot in order to achieve a more stable state.
And step five, designing a state machine for switching the diagonal sprint gait, which is shown in figure 3. The method specifically comprises the following steps:
and 5.1, designing a state machine set for switching the diagonal sprint gait.
Specifically, the set includes nine states, respectively state 1 — four feet are grounded simultaneously; state 2-the right front leg and the left rear leg swing in the air while the left front leg and the right rear leg are grounded; state 3-the right front leg and the left rear leg swing in the air while landing; state 4 — in state 2, the right front leg and the left rear leg are touching the ground simultaneously; in the state 4.1-state 2, the right front leg touches the ground before the left rear leg; state 4.2 — in state 2, the left rear leg touches the ground before the right front leg; state 5 — in state 3, the left front leg and the right rear leg are touching the ground simultaneously; in the state 5.1-state 3, the left front leg touches the ground before the right rear leg; in the state 5.2-state 3, the right rear leg touches the ground before the left front leg.
And 5.2, combining the touchdown information of each leg to switch the diagonal running state.
Specifically, the initial state is state 1 first, with the four feet grounded simultaneously. After the standby body is stable for a certain time, namely the horizontal speed of the mass center of the body
Less than threshold
And (3) swinging the legs at the back, swinging the pair of virtual legs of the right front leg and the left rear leg at first, and switching the state to the state 2. Next, if the right front leg and the left rear leg touch the ground simultaneously, the state is switched to the state 4; if the right front leg is touching the ground before the left rear leg, the state switches to state 4.1, at which time the right front leg is touching the groundThe legs stop swinging, the left rear leg is waited to touch the ground, and then the state is switched to a state 4; if the left rear leg touches the ground before the right front leg, the state switches to state 4.2, at which time the left rear leg stops swinging, waiting for the right front leg to touch the ground, and then the state switches to state 4. When the state is switched to the state 4, the quadruped robot is in the quadruped supporting phase at the moment, and the quadruped supporting phase is enabled to be in the time Tst,4Equal to the entire movement period T (including the support phase period T)stAnd the period T of the wobble phasesw) 10% of the total. Then the state is switched to the state 3, and the pair of virtual legs of the left front leg and the right rear leg is swung. Next, if the left front leg and the right rear leg touch the ground simultaneously, the state is switched to the state 5; if the left front leg contacts the ground before the right rear leg, the state is switched to a state 5.1, at the moment, the left front leg stops swinging, the right rear leg is waited to contact the ground, and then the state is switched to a state 5; if the right rear leg touches the ground before the left front leg, the state switches to state 5.2, at which time the right rear leg stops swinging, waiting for the left front leg to touch the ground, and then the state switches to state 5. When the state is switched to the state 5, the quadruped robot is in the quadruped supporting phase at the moment, and the quadruped supporting phase is enabled to be in the time Tst,4Equal to 10% of the total movement period T. Then the state is switched to the state 2, and the pair of virtual legs of the right front leg and the left rear leg is swung. Therefore, the state machine forms a cycle, and then the cycle is continuously repeated according to the state machine to realize diagonal jogging gait walking.
And step six, establishing an impedance controller and a virtual model controller of the quadruped robot. The method specifically comprises the following steps:
and 6.1, dividing the state of each leg into a support phase and a swing phase.
Specifically, whether the leg is in the support phase or the swing phase is determined based on a plantar laser distance sensor.
Step 6.2, for the leg in the swing phase, the impedance controller is designed, see fig. 4.
Specifically, the outer loop is designed to be an impedance controller and the inner loop is designed to be a force controller. The impedance controller of the outer loop is essentially a low-gain PD controller, and the expected value x of the foot end track is obtainedd、
Error x from the actual value,
As input, the foot end virtual force F is inputteddAs output, the virtual moment tau is generated by combining a single-leg dynamic modeldAs an input to the inner loop controller. The resistance controller based on force of the inner ring and the outer ring can dynamically adjust the relation between force and position, flexibly follow the track of the foot end, reduce the impact force when the foot end touches the ground and enhance the stability of the body during movement.
In particular, the PD control parameters of the outer ring may be combined with the feedback value τ of the joint force sensorjoint,ijAdjustment of the fuzzy rule is performed. Generally speaking, the PD parameter of the swing leg is smaller than the PD parameter of the support leg, so as to achieve a more compliant effect, thereby enhancing the stability of the body.
And 6.3, for the leg in the supporting phase, calculating virtual force by assuming a virtual spring damping model in three translation directions at the hip part of the leg, calculating virtual moment by assuming a virtual spring damping model with three rotational degrees of freedom at the center of mass, and converting the virtual force into the virtual force and the virtual moment of the supporting leg.
Specifically, for the leg in the supporting phase, the force required by the motion in the three translational directions of xyz is equivalent to the hip, and the force can be calculated according to the expected state and the actual state
Wherein F is a three-dimensional force, Pd、P、
Respectively a desired three-dimensional position, an actual three-dimensional position, a desired three-dimensional velocity, an actual three-dimensional velocity, to
For the purpose of example only,
Kst、Cstthe PD control parameter.
And calculating virtual moment at the mass center according to the virtual spring damping model and the attitude angle. Wherein the pitch angle thetapitchThe height of the hip of the front foot and the rear foot is adjusted to carry out indirect control, and the control is not carried out directly. Roll moment taurollAnd yaw moment τyawThe calculation process is as follows:
wherein, thetarolld、θroll、
Respectively representing an expected rolling angle, an actual rolling angle, an expected rolling angular speed and an actual rolling angular speed; thetayawd、θyaw、
Desired yaw angle, actual yaw angle, desired yaw angular velocity, actual yaw angular velocity, k, respectivelyroll、croll、kyaw、cyawThe PD control parameter.
Then, the virtual yaw moment tau obtained at the centroid is comparedyawForward direction of decomposition to hip, i.e. x direction:
Δfx＝τyaw/w
wherein w is the width of the fuselage.
Total virtual force acting on the hip:
Fsum＝F+[Δfx；0；0]
the virtual force of the hip is converted into three joint moments through a jacobian matrix of the leg.
τ＝-J′Fsum
Wherein J is a one-legged Jacobian matrix.
Finally, the virtual roll torque tau is calculatedrollAnd (3) decomposing to the hip joint:
due to the fact that the actual joint motor has output torque limitation, attention is paid to a given torque threshold value tausum,max。
The key points of the technology of the invention are as follows:
1. a four-footed robot diagonal gait compliance control method based on drop foot point adjustment comprises the following steps: establishing a simplified rigid body model of the quadruped robot; according to the simplified rigid body model, combining sensor data such as a motor encoder, a foot sole laser distance sensor, a joint force sensor, an IMU and the like to calculate and obtain a joint angle, a ground contact signal, a hip motion state and a body mass center posture; adjusting foot falling points and planning a foot end track with self-adaptive leg lifting height; designing starting posture and walking transition, and carrying out diagonal sprint gait planning; designing a state machine for switching the diagonal sprint gait; and establishing an impedance controller and a virtual model controller of the quadruped robot.
2. And establishing a simplified rigid body model of the quadruped robot. And establishing a world coordinate system, a body coordinate system and a joint coordinate system in the space. For simplicity of modeling and control, the mass and moment of inertia of the four legs are ignored, since the leg mass is substantially negligible relative to the fuselage mass. And establishing a simplified rigid body model of the quadruped robot to obtain a kinematic equation, a leg Jacobian matrix and the like of the model.
3. And calculating according to the simplified rigid body model and combining sensor data such as a motor encoder, a foot sole laser distance sensor, a joint force sensor, an IMU and the like to obtain a joint angle, a ground contact signal, a hip motion state and a body mass center posture.
4. A foot end trajectory planning method with self-adaptive foot drop point adjustment, leg lifting height and support phase time. Giving a foot end trajectory equation in three directions of a swing phase x, y and z; the leg raising height of the foot end is properly adjusted according to the terrain. Can be better adapted to the terrain and improve the motion stability.
5. Designing starting posture and walking transition, and carrying out diagonal sprint gait planning. On the basis of stepping, the robot moves for a half gait cycle in a half step length, and then is switched into a full step length to carry out diagonal running motion, so that on one hand, the stable transition of the speed of the robot can be ensured, the sudden change of the speed of the robot cannot be caused, on the other hand, the position of a foot end relative to a hip joint can be ensured to be kept in a symmetrical state, and the stability of the motion is facilitated.
6. And designing a state machine for switching the diagonal sprint gait. Designing a state machine set for switching the diagonal sprint gait; and combining the touchdown information of each leg to switch the diagonal running state. Considering more actual grounding conditions, the switching method of the state machine comprises the sequential problem of swinging legs to land, and four-foot support for adjusting the attitude of the machine body and improving the stability of the machine body is equal.
7. An impedance controller for the swing phase and a virtual model controller for the support phase. Dividing the state of each leg into a support phase and a swing phase; for the leg in the swing phase, designing an impedance controller; for the leg in the supporting phase, a virtual spring damping model in three translation directions is assumed at the hip part of the leg to calculate virtual force, and a virtual spring damping model in three rotational degrees of freedom is assumed at the mass center to calculate virtual moment so as to convert the virtual force into the virtual force and the virtual moment of the supporting leg; the virtual force of the hip is converted into three joint moments through a jacobian matrix of the leg.
The above-described embodiments are merely preferred embodiments of the present invention, and should not be construed as limiting the scope of the invention. All equivalent changes and modifications made within the scope of the present invention shall fall within the scope of the present invention.
Claims (6)
1. A four-footed robot diagonal gait compliance control method based on foot drop point adjustment is characterized by comprising the following steps:
1) establishing a simplified rigid body model of the quadruped robot;
2) according to the simplified rigid body model, combining sensor data such as a motor encoder, a foot sole laser distance sensor, a joint force sensor, an IMU and the like to calculate and obtain a joint angle, a ground contact signal, a hip motion state and a body mass center posture;
3) adjusting foot falling points and planning a foot end track with self-adaptive leg lifting height;
4) designing starting posture and walking transition, and carrying out diagonal sprint gait planning;
5) designing a state machine for switching the diagonal sprint gait;
6) and establishing an impedance controller and a virtual model controller for the motion of the quadruped robot.
2. The diagonal gait compliance control method of the quadruped robot based on the adjustment of the foot drop point as claimed in claim 1, wherein in the step 1), the simplified rigid body model of the quadruped robot is established by establishing a world coordinate system, a body coordinate system and a joint coordinate system in the space; for simplicity of modeling and control, the mass and the moment of inertia of the four legs are ignored, a simplified rigid body model of the quadruped robot is established, and a kinematic equation and a leg Jacobian matrix of the model are obtained.
3. The diagonal gait compliance control method of the quadruped robot based on the foot drop point adjustment as claimed in claim 1, wherein in the step 3), the specific steps of performing the foot tip trajectory planning of the foot drop point adjustment and the leg raising height self-adaptation are as follows:
step 3.1, setting foot end trajectory equations in the x, y and z directions of the swing phase;
and 3.2, properly adjusting the leg lifting height of the foot end according to the terrain condition.
4. The diagonal gait compliance control method of the quadruped robot based on the adjustment of the drop foot point as claimed in claim 1, characterized in that in step 4), the specific steps of designing the starting posture and the walking transition and performing the diagonal sprint gait planning are as follows:
on the basis of stepping, the robot moves for a half gait cycle in a half step length, and then is switched into a full step length to carry out diagonal running motion, so that on one hand, the stable transition of the speed of the robot can be ensured, the sudden change of the speed of the robot cannot be caused, on the other hand, the position of a foot end relative to a hip joint can be ensured to be kept in a symmetrical state, and the stability of the motion is facilitated.
5. The diagonal gait compliance control method of the quadruped robot based on the foot drop point adjustment as claimed in claim 1, characterized in that in step 5), the specific steps of designing the state machine for switching the diagonal sprint gait are as follows:
step 5.1, designing a state machine set for switching the diagonal sprint gait;
step 5.2, combining the touchdown information of each leg to switch the diagonal running state; considering more actual grounding conditions, the switching method of the state machine comprises the sequential problem of swinging legs to land and a four-foot supporting phase for adjusting the posture of the machine body and improving the stability of the machine body.
6. The diagonal gait compliance control method of the quadruped robot based on the foot drop point adjustment as claimed in claim 1, wherein in step 6), the specific steps of establishing the impedance controller and the virtual model controller of the quadruped robot motion are as follows:
step 6.1, dividing the state of each leg into a support phase and a swing phase;
step 6.2, designing an impedance controller for the leg in the swing phase;
step 6.3, for the leg in the supporting phase, a virtual spring damping model in three translation directions is assumed at the hip part of the leg to calculate virtual force, and a virtual spring damping model in three rotational degrees of freedom is assumed at the mass center to calculate virtual moment so as to convert the virtual force and the virtual moment into the virtual force and the virtual moment of the supporting leg; the virtual force of the hip is converted into three joint moments through a jacobian matrix of the leg.
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115202372A (en) * | 2022-09-19 | 2022-10-18 | 泰州朵儿智能科技有限公司 | Bionic quadruped robot control system and method based on foot end force adjustment |
| CN117148740A (en) * | 2023-10-31 | 2023-12-01 | 江西机电职业技术学院 | Combined simulation gait planning method for desktop-level four-foot robot |
| CN117260718A (en) * | 2023-09-21 | 2023-12-22 | 广东工业大学 | Self-adaptive load compensation control method and system for four-legged robot |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2021174796A1 (en) * | 2020-03-05 | 2021-09-10 | 亿嘉和科技股份有限公司 | Grabbing attitude calculation method in scenario where live-working robot grabs branch line |
| CN114423372A (en) * | 2019-09-19 | 2022-04-29 | 奥瑞斯健康公司 | Coordinated movement of robotic tools |
-
2022
- 2022-01-14 CN CN202210047113.1A patent/CN114384918A/en active Pending
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114423372A (en) * | 2019-09-19 | 2022-04-29 | 奥瑞斯健康公司 | Coordinated movement of robotic tools |
| WO2021174796A1 (en) * | 2020-03-05 | 2021-09-10 | 亿嘉和科技股份有限公司 | Grabbing attitude calculation method in scenario where live-working robot grabs branch line |
Non-Patent Citations (6)
| Title |
|---|
| 司海飞;胡兴柳;余振中;唐玉娟;: "四足机器人对角小跑步态非线性控制方法仿真", 计算机仿真, no. 01 * |
| 李鑫: "基于虚拟模型和阻抗控制的四足液压驱动机器人行走研究", 中国优秀硕士学位论文全文数据库信息科技辑, pages 140 - 1574 * |
| 王立鹏: "液压四足机器人驱动控制与步态规划研究", 中国博士学位论文全文数据库信息科技辑, pages 140 - 35 * |
| 谢惠祥: "四足机器人对角小跑步态虚拟模型直觉控制方法研究", 中国博士学位论文全文数据库信息科技辑, pages 140 - 128 * |
| 谭永营;晁智强;韩寿松;宁初明;: "基于重心动力学及虚拟模型的负载型四足步行平台对角步态控制方法", 机器人, no. 04 * |
| 陈志华;汪首坤;王军政;徐康;王修文;刘道和;雷涛;司金戈;: "电动并联六轮足机器人的运动驱动与多模态控制方法", 机器人, no. 05 * |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115202372A (en) * | 2022-09-19 | 2022-10-18 | 泰州朵儿智能科技有限公司 | Bionic quadruped robot control system and method based on foot end force adjustment |
| CN117260718A (en) * | 2023-09-21 | 2023-12-22 | 广东工业大学 | Self-adaptive load compensation control method and system for four-legged robot |
| CN117148740A (en) * | 2023-10-31 | 2023-12-01 | 江西机电职业技术学院 | Combined simulation gait planning method for desktop-level four-foot robot |
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