CN110812131A

CN110812131A - Gait control method and control system of exoskeleton robot and exoskeleton robot

Info

Publication number: CN110812131A
Application number: CN201911188754.3A
Authority: CN
Inventors: 张旭; 叶晶; 陈功; 王宇谦; 吴诚; 张悦; 孙慧杰; 郭登极; 黄守仁; 薛林
Original assignee: Shenzhen Step Robot Technology Co Ltd
Current assignee: Shenzhen Step Robot Technology Co Ltd
Priority date: 2019-11-28
Filing date: 2019-11-28
Publication date: 2020-02-21
Anticipated expiration: 2039-11-28
Also published as: CN110812131B

Abstract

The invention provides a gait control method and a control system of an exoskeleton robot and the exoskeleton robot, wherein the gait control method comprises the following steps: setting step length and step height; and fitting by adopting a spline curve to generate a sole swing track of the swing leg according to the step length and the step height, calculating a hip joint swing angle and a knee joint swing angle of the swing leg by adopting a trigonometric function relation according to the sole swing track, and controlling the swing leg to execute walking action according to the calculated angle. The planned gait of the invention accords with the motion rule of the human body; and can plan the corresponding foot gait track according to the individual difference, and the adjustment is convenient.

Description

Gait control method and control system of exoskeleton robot and exoskeleton robot

Technical Field

The invention belongs to the field of exoskeleton robots, and particularly relates to a gait control method and a control system of an exoskeleton robot and the exoskeleton robot.

Background

The lower limb assistance exoskeleton robot is a novel wearable intelligent device, integrates physical force of a mechanical system and intelligence of human into one system, the mechanical system becomes one part of a human body, so that a wearer can complete tasks which cannot be completed only by the self condition of the human body, and the motion capability and the load bearing capability of the human body are improved.

The existing lower limb assistance exoskeleton robot only generally outputs a fixed gait track, the gait track has different requirements along with different conditions due to the difference of the height, the sex and the like of people, if the exoskeleton cannot ensure a proper gait track, the comfort and the balance are reduced, and even certain damage to the lower limbs of a patient is possibly caused.

Therefore, the prior art has yet to be developed.

Disclosure of Invention

The invention aims to provide a gait control method and a control system of an exoskeleton robot and the exoskeleton robot, and aims to solve the problem that the conventional exoskeleton robot cannot adjust a gait track according to actual conditions.

In order to solve the above technical problem, the present invention is implemented as a gait control method of an exoskeleton robot, including:

setting step length and step height;

and fitting by adopting a spline curve to generate a sole swing track of the swing leg according to the step length and the step height, calculating a hip joint swing angle and a knee joint swing angle of the swing leg by adopting a trigonometric function relation according to the sole swing track, and controlling the swing leg to execute walking action according to the calculated angle.

Further, the sole oscillation trajectory includes the following four phases:

phase 1, pre-swing phase: the point A is set when the knee joint is bent and the hip joint is over-extended and the foot is not away from the starting place;

phase 2, kick off phase: lifting the foot away from the point A, swinging to the maximum height, and setting as a point B;

phase 3, foot extension phase: the foot extends forwards until the unfolding angle of the knee joint reaches a preset threshold value, and the position of the foot at the moment is set as a point C;

phase 4, foot landing stage: the foot falls to the ground from the point C and is set as a point D;

wherein, the distance from the point A to the point D is the step length, and the height of the point B is the step height; fitting the track AB by adopting a first spline curve; fitting the track BC by adopting a second spline curve; the trace CD is fitted with a third spline curve.

Further, setting a step frequency T, wherein the step frequency is the walking time required for completing a complete swing gait;

the control swing leg executes walking action according to the sole swing track, and the control swing leg comprises:

setting time T1 for the initial state to move to phase 1;

setting time T2 for phase 1 to move to phase 2;

setting time T3 for phase 2 to move to phase 3;

setting time T4 for phase 3 to move to phase 4;

controlling the swing leg to move on the sole swing track according to the time;

wherein T1+ T2+ T3+ T4 ═ T.

Further, the controlling the swing leg to perform the walking motion according to the calculated angle includes: and detecting the swing angle of the hip joint and the swing angle of the knee joint, and driving the swing leg to switch from phase 1 to phase 2 when the hip joint swings to a first hip joint preset angle value and the knee joint swings to a first knee joint preset angle value.

Further, the controlling the swing leg to perform the walking motion according to the calculated angle includes: and detecting the swing angles of the hip joint and the knee joint, and driving the swing leg to switch from a phase 2 to a phase 3 when the hip joint swings to a line perpendicular to the ground with the toe.

Further, the controlling the swing leg to perform the walking motion according to the calculated angle includes: and detecting the swing angle or the current step length of the knee joint, and when the knee joint swings to a preset angle value of a second knee joint or the current step length reaches a preset step length value, driving the swing leg to switch from the phase 3 to the phase 4.

An exoskeleton robot control system comprises

The setting module is used for setting step length and step height;

the sole swing track calculation module is used for generating a sole swing track of the swing leg by adopting spline curve fitting according to the step length and the step height;

a joint angle calculation module to: calculating the hip joint swing angle and the knee joint swing angle of the swing leg by adopting a trigonometric function relation according to the sole swing track; and the swing leg swing control module is used for controlling the exoskeleton robot to execute walking action according to the hip joint swing angle and the knee joint swing angle.

An exoskeleton robot comprising a waist, a thigh section connected to the waist by a hip joint, a lower leg section connected to the thigh section by a knee joint, and a foot section connected to the lower leg section by an ankle joint;

the hip joint and the knee joint are provided with driving mechanisms for controlling the swinging of the thigh part and the lower leg part;

the exoskeleton robot is provided with the exoskeleton robot control system for controlling the driving mechanism to move.

A computer readable storage medium comprising a set of computer executable instructions which when executed perform a gait control method as described above.

Compared with the prior art, the invention has the beneficial effects that: the gait control method of the exoskeleton robot comprises the steps of setting step length and step height, adopting spline curve fitting to generate a sole swing track of a swing leg, calculating an angle to be output by a swing leg joint according to the sole swing track, and controlling the swing leg to execute walking action according to the angle. The gait planned in this way conforms to the motion law of the human body; and can plan the compatible gait track according to the individual difference, and the adjustment is convenient.

Drawings

Fig. 1 shows a model structure of the exoskeleton robot of the present invention.

Fig. 2 is a model structure diagram of the exoskeleton robot walking on a horizontal ground.

Fig. 3 is a model configuration diagram of the exoskeleton robot walking on a slope according to the present invention.

Fig. 4 is a schematic phase-resolved representation of the exoskeleton robot foot base gait trajectory of the present invention.

Fig. 5 is a block diagram of an exoskeleton robot control system of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

The exoskeleton robot is a novel wearable intelligent device, the swing legs of the robot are abstracted into a two-link mechanism in the embodiment of the invention, as shown in fig. 1, the exoskeleton robot comprises a waist part 1, a thigh part 2, a shank part 3 and a foot part 4, the waist part 1 and the thigh part 2 are connected through a hip joint 12, the thigh part 2 and the shank part 3 are connected through a knee joint 23, the shank part 3 and the foot part 4 are connected through an ankle joint, and the hip joint and the knee joint are provided with driving mechanisms for controlling the swing of the thigh part and the shank part so that the exoskeleton robot can walk. In the embodiment of the invention, in order to simplify the model, the ankle joint is assumed to be kept unchanged at 90 degrees.

Based on the model, the embodiment of the invention provides a gait control method of an exoskeleton robot, which comprises the following steps: setting step length and step height.

As shown in fig. 2, MNF is a swing leg, where M is a hip joint, N is a knee joint, the step length is L, the step height is H, and the curve is a swing trajectory of the foot F and is fit by a spline curve according to the step length and the step height, and the spline curve includes, but is not limited to, a primary curve and a secondary curve. In this embodiment, the step length and the step height can be selected according to the height, age or gender of the patient, so as to obtain different sole swing trajectories. If the condition is an uphill condition, when the initial parameters are set, the inclination angle theta of the slope can be set, and as shown in fig. 3, a suitable sole swing track is planned according to different individuals and environments, so that the adjustment is convenient. And calculating the hip joint swing angle and the knee joint swing angle of the swing leg by adopting a trigonometric function relation according to the sole swing track, and controlling the swing leg to execute walking action according to the calculated angle. Specifically, the length of the MF can be calculated from the coordinates of the F point; the leg length of the user can be directly measured and obtained, namely MN and NF are known, the angles of three angles of the triangle can be calculated according to the side length of the triangle, and the angles of the hip joint and the knee joint can be calculated according to the angles. Namely, the invention can control the motion of the sole according to the sole swing track curve in the figure by controlling the angles of the hip joint and the knee joint.

In the embodiment, the planned gait conforms to the motion rule of the human body by setting the step length and the step height and taking the body state (leg length) of the human body as basic input parameters; and the three parameters can adjust the gait track according to the actual conditions of the height, the sex and the like of the person, optionally, the gait track can be adjusted according to road conditions (level road or uphill and downhill) to generate the sole swing track of uphill and downhill. After the swing track of the sole is generated, the track is controlled, and the method can adjust the swing track according to the actual condition.

For a complete sole swing track, the invention can divide the sole swing track into the following four phases, and as shown in fig. 4, each phase can be controlled by joint swing time and joint swing angles (α 1, α 2).

Phase 1, pre-swing phase: the point A is set when the foot is not yet at the beginning of flexion of the knee joint and hyperextension of the hip joint. In this stage, the hip joint and the knee joint do further bending movements, the foot is not yet lifted off the ground, and point a is the starting point of the step length.

The pre-swing phase, time T1 being shorter, can be set to 10% of the time taken for the whole step, i.e. the swing leg switches to phase 2 after swinging according to the sole swing trajectory for a predetermined time T1. The control can also be carried out through the leg swinging angle, and when the hip joint swings to the first hip joint preset angle value and the knee joint swings to the first knee joint preset angle value, the swinging leg is driven to switch from the phase 1 to the phase 2. For example, the phase switch is performed when the hip joint moves to-10 ° and the knee joint moves to-40 °, and the minus sign indicates that the thigh and the calf are both bent backward (-x direction) at this stage. The time and the angle can be adjusted according to actual conditions, and a timing module or an angle detection module is arranged at a joint to respectively detect the swing time and the swing angle during application. The embodiment of the invention can also control the swinging time and the swinging angle at the same time, namely the hip joint swings to the first hip joint preset angle value in the preset time, and the knee joint swings to the first knee joint preset angle value, so that the swinging leg is driven to switch from the phase 1 to the phase 2. For example, when the walking speed needs to be increased, the swing leg can be controlled to reach the preset angle value in a short time, and the corresponding setting can be made according to the principle in the following, so that the control of the walking speed can be realized.

Phase 2, kick off phase: and lifting the foot away from the point A, swinging to the maximum height, and setting as a point B. In this stage, the swing leg is lifted off the ground and swings to the highest point, the foot bottom track is a smooth curve, and a spline curve (a first spline curve) can be adopted for fitting. Specifically, a spline curve is adopted to connect the point A and the point B, and then a filter is used for smoothing the trajectory to obtain the sole swing trajectory in the AB stage, wherein the spline curve comprises but is not limited to a primary curve and a secondary curve. In this embodiment, the phase control can be performed by setting the time period T2 for this phase, for example, T2 is set to 30-50% of the time taken for the whole step, i.e., the swing leg swings according to the sole swing trajectory for a predetermined time T2, and then the phase is switched to phase 3. The control can also be carried out through the swing angle of the leg, for example, when the connecting line of the toe and the hip joint fulcrum is vertical to the ground, the maximum step height in gait can be reached, the angles of the hip joint and the knee joint can be respectively calculated according to the constraint condition, so that the phase can be controlled by detecting the swing angles of the hip joint and the knee joint, when the angle reaches the preset condition, the foot off-ground phase is considered to be completed, and the gait phase is switched to the phase 3.

Phase 3, foot extension phase: the foot extends forwards until the unfolding angle of the knee joint reaches a preset threshold value, and the position of the foot at the moment is set as a point C. In this stage, when the knee joint swings to a preset angle value of the second knee joint, the swing leg is driven to switch from the phase 3 to the phase 4. The plantar track is a smooth curve that can be fitted using a spline curve (second spline curve). The method is the same as above and is not described in detail. In this embodiment, the phase control can be performed by setting the time period T3 for this phase, for example, T3 is set to 40-50% of the time taken for the whole step, i.e., the swing leg swings according to the sole swing trajectory for a predetermined time T3, and then the phase is switched to phase 4. The gait phase can also be controlled by the leg swing angle or the current step length, when the gait phase is in the phase 3, the hip joint is in the state of the maximum angle of forward swing, and when the knee joint is unfolded to the maximum angle (the value of the preset angle of the second knee joint), the gait phase is switched to the phase 4. Preferably, when the knee joint is unfolded to the maximum preset angle, the knee joint swings back by 5 degrees and then is switched to a step state, so that the knee joint is prevented from being stretched excessively. The switching can also be performed by detecting the current step length, and if the current step length reaches the preset step length value, the swing leg is driven to switch from the phase 3 to the phase 4.

Phase 4, foot landing stage: and the foot falls to the ground from the point C and is set as a point D. In order to realize stable landing, the angles of the hip joint and the knee joint at the point C are finely adjusted, so that the landing stage presents a stable posture that the heel lands first. The CD segments may be fitted using a spline curve (third spline curve). The method is the same as above and is not described in detail. In this embodiment, the phase control can be performed by setting the time T4 for this phase, for example, T4 is set to 5% of the time taken for the whole step, that is, after the swing leg swings according to the sole swing locus for a predetermined time T3, the foot comes to the ground. The angle of the swing of the leg can also be controlled, for example, when the thigh keeps the swing angle of the hip joint relative to the point C and the knee joint swings back 7 degrees compared with the maximum preset angle (unfolding angle), namely swings back 2 degrees compared with the point C, and then the gravity center of the human body is adjusted to make the swing leg naturally fall to the ground. Whether the sole falls to the ground can be judged by detecting the pressure of the sole.

In the figure, the distance from the point A to the point D is the step length, and the height of the point B is the step height; t1+ T2+ T3+ T4 is T, T being the preset stride frequency, which is the walking time required to complete a complete gait.

In the embodiment of the invention, based on the planned sole swing track and gait phase, the switching of the gait phase can be controlled through the leg swing time, and the sole swing track and the switching of each phase can be controlled in an auxiliary way by controlling the swing angle thresholds of the hip joint and the knee joint. The foot swing track is according to human motion law to the difference of individual and environment has been considered, can adjust the gait track according to actual conditions.

The present invention also provides an embodiment of an exoskeleton robot control system, as shown in fig. 5, comprising: and the setting module 10 is used for setting step length and step height. And the sole gait track calculation module 20 is used for generating the sole swing track of the swing leg by adopting spline curve fitting according to the step length and the step height. And the joint angle calculation module 30 is used for calculating the hip joint swing angle and the knee joint swing angle of the swing leg by adopting a trigonometric function relation according to the sole swing track. And the swing leg gait control module 40 is used for controlling the exoskeleton robot to execute walking action according to the hip joint swing angle and the knee joint swing angle.

Based on the exoskeleton robot control system, the embodiment of the invention also provides an exoskeleton robot, which comprises a waist, a thigh part connected with the waist through a hip joint, a shank part connected with the thigh part through a knee joint, and a foot part connected with the shank part through an ankle joint; the hip joint and the knee joint are provided with driving mechanisms for controlling the swinging of the thigh part and the lower leg part; the exoskeleton robot is provided with the exoskeleton robot control system for controlling the driving mechanism to move.

In addition to the methods and apparatus described above, embodiments of the present application may also be a computer program product comprising computer program instructions that, when executed by a processor, cause the processor to perform the steps in the gait control method according to the various embodiments of the present application described in the "exemplary methods" section above of this specification.

The computer program product may be written with program code for performing the operations of embodiments of the present application in any combination of one or more programming languages, including an object oriented programming language such as Java, C + + or the like and conventional procedural programming languages, such as the "C" programming language or similar programming languages. The program code may execute entirely on the user's computing device, partly on the user's device, as a stand-alone software package, partly on the user's computing device and partly on a remote computing device, or entirely on the remote computing device or server.

Furthermore, embodiments of the present application may also be a computer-readable storage medium having stored thereon computer program instructions that, when executed by a processor, cause the processor to perform steps in a testing method according to various embodiments of the present application described in the "exemplary methods" section above of this specification.

The computer-readable storage medium may take any combination of one or more readable media. The readable medium may be a readable signal medium or a readable storage medium. A readable storage medium may include, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or a combination of any of the foregoing. More specific examples (a non-exhaustive list) of the readable storage medium include: an electrical connection having one or more wires, a portable disk, a hard disk, a Random Access Memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

The foregoing describes the general principles of the present application in conjunction with specific embodiments, however, it is noted that the advantages, effects, etc. mentioned in the present application are merely examples and are not limiting, and they should not be considered essential to the various embodiments of the present application. Furthermore, the foregoing disclosure of specific details is for the purpose of illustration and description and is not intended to be limiting, since the foregoing disclosure is not intended to be exhaustive or to limit the disclosure to the precise details disclosed.

The block diagrams of devices, apparatuses, systems referred to in this application are only given as illustrative examples and are not intended to require or imply that the connections, arrangements, configurations, etc. must be made in the manner shown in the block diagrams. These devices, apparatuses, devices, systems may be connected, arranged, configured in any manner, as will be appreciated by those skilled in the art. Words such as "including," "comprising," "having," and the like are open-ended words that mean "including, but not limited to," and are used interchangeably therewith. The words "or" and "as used herein mean, and are used interchangeably with, the word" and/or, "unless the context clearly dictates otherwise. The word "such as" is used herein to mean, and is used interchangeably with, the phrase "such as but not limited to".

It should also be noted that in the devices, apparatuses, and methods of the present application, the components or steps may be decomposed and/or recombined. These decompositions and/or recombinations are to be considered as equivalents of the present application.

The previous description of the disclosed aspects is provided to enable any person skilled in the art to make or use the present application. Various modifications to these aspects will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other aspects without departing from the scope of the application. Thus, the present application is not intended to be limited to the aspects shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.

Claims

1. A gait control method of an exoskeleton robot, comprising:

setting step length and step height;

2. A gait control method of an exoskeleton robot as claimed in claim 1 wherein said plantar swing trajectory includes four phases:

3. A gait control method for an exoskeleton robot as claimed in claim 2 wherein a step frequency T is set, said step frequency being the walking time required to complete a full swing gait;

setting time T1 for the initial state to move to phase 1;

setting time T2 for phase 1 to move to phase 2;

setting time T3 for phase 2 to move to phase 3;

setting time T4 for phase 3 to move to phase 4;

wherein T1+ T2+ T3+ T4 ═ T.

4. A gait control method of an exoskeleton robot as claimed in claim 2 wherein said controlling the swing leg to perform a walking motion at a calculated angle comprises:

and detecting the swing angle of the hip joint and the swing angle of the knee joint, and driving the swing leg to switch from phase 1 to phase 2 when the hip joint swings to a first hip joint preset angle value and the knee joint swings to a first knee joint preset angle value.

5. A gait control method of an exoskeleton robot as claimed in claim 2 wherein said controlling the swing leg to perform a walking motion at a calculated angle comprises:

and detecting the swing angles of the hip joint and the knee joint, and driving the swing leg to switch from a phase 2 to a phase 3 when the hip joint swings to a line perpendicular to the ground with the toe.

6. A gait control method of an exoskeleton robot as claimed in claim 2 wherein said controlling the swing leg to perform a walking motion at a calculated angle comprises:

and detecting the swing angle or the current step length of the knee joint, and when the knee joint swings to a preset angle value of a second knee joint or the current step length reaches a preset step length value, driving the swing leg to switch from the phase 3 to the phase 4.

7. An exoskeleton robot control system is characterized by comprising

The setting module is used for setting step length and step height;

the joint angle calculation module is used for calculating the hip joint swing angle and the knee joint swing angle of the swing leg by adopting a trigonometric function relation according to the sole swing track;

and the swing leg swing control module is used for controlling the exoskeleton robot to execute walking action according to the hip joint swing angle and the knee joint swing angle.

8. An exoskeleton robot comprising a waist portion, a thigh portion connected to the waist portion via a hip joint, a shank portion connected to the thigh portion via a knee joint, and a foot portion connected to the shank portion via an ankle joint;

the exoskeletal robot is loaded with the exoskeletal robot control system of claim 7 for controlling the movement of the drive mechanism.

9. A computer-readable storage medium comprising a set of computer-executable instructions that, when executed, perform the method of any of claims 1 to 6.