CN114147741B - Multi-degree-of-freedom wearable exoskeleton hand function rehabilitation robot based on redundant control - Google Patents
Multi-degree-of-freedom wearable exoskeleton hand function rehabilitation robot based on redundant control Download PDFInfo
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Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
- B25J—MANIPULATORS; CHAMBERS PROVIDED WITH MANIPULATION DEVICES
- B25J11/00—Manipulators not otherwise provided for
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
- B25J—MANIPULATORS; CHAMBERS PROVIDED WITH MANIPULATION DEVICES
- B25J13/00—Controls for manipulators
- B25J13/08—Controls for manipulators by means of sensing devices, e.g. viewing or touching devices
- B25J13/085—Force or torque sensors
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
- B25J—MANIPULATORS; CHAMBERS PROVIDED WITH MANIPULATION DEVICES
- B25J15/00—Gripping heads and other end effectors
- B25J15/0009—Gripping heads and other end effectors comprising multi-articulated fingers, e.g. resembling a human hand
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
- B25J—MANIPULATORS; CHAMBERS PROVIDED WITH MANIPULATION DEVICES
- B25J15/00—Gripping heads and other end effectors
- B25J15/08—Gripping heads and other end effectors having finger members
- B25J15/10—Gripping heads and other end effectors having finger members with three or more finger members
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
- B25J—MANIPULATORS; CHAMBERS PROVIDED WITH MANIPULATION DEVICES
- B25J9/00—Programme-controlled manipulators
- B25J9/0006—Exoskeletons, i.e. resembling a human figure
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
- B25J—MANIPULATORS; CHAMBERS PROVIDED WITH MANIPULATION DEVICES
- B25J9/00—Programme-controlled manipulators
- B25J9/08—Programme-controlled manipulators characterised by modular constructions
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
- B25J—MANIPULATORS; CHAMBERS PROVIDED WITH MANIPULATION DEVICES
- B25J9/00—Programme-controlled manipulators
- B25J9/16—Programme controls
- B25J9/1602—Programme controls characterised by the control system, structure, architecture
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
- B25J—MANIPULATORS; CHAMBERS PROVIDED WITH MANIPULATION DEVICES
- B25J9/00—Programme-controlled manipulators
- B25J9/16—Programme controls
- B25J9/1656—Programme controls characterised by programming, planning systems for manipulators
- B25J9/1664—Programme controls characterised by programming, planning systems for manipulators characterised by motion, path, trajectory planning
Abstract
The invention discloses a multi-degree-of-freedom wearable exoskeleton hand function rehabilitation robot based on redundant control, which comprises the following components: the device comprises a palmback platform, a finger link mechanism, a steering engine, a pressure sensor and a control module, wherein the finger link mechanism, the steering engine, the pressure sensor and the control module are arranged on the palmback platform; the finger link mechanism comprises a finger platform and a multi-degree-of-freedom link, wherein the multi-degree-of-freedom link is provided with a plurality of joints, and each joint is driven by an independent steering engine; the finger platform is provided with a pressure sensor for detecting fingertip force in the process of grasping; the control module simulates a fingertip movement track according to the target fingertip position, and controls the torque of the steering engine according to the fingertip movement track so as to drive the steering engine to rotate; and controlling and adjusting the torque and the rotation speed of the steering engine according to the difference value between the actual fingertip force and the target fingertip force and the difference value between the actual fingertip position and the target fingertip position. And the motion track is accurately estimated according to the fingertip position by adopting redundant control, and the fingertip force is regulated by adopting force feedback control, so that the stability of the grasping process is improved.
Description
Technical Field
The invention relates to the technical field of rehabilitation robots, in particular to a multi-degree-of-freedom wearable exoskeleton hand function rehabilitation robot based on redundant control.
Background
The statements in this section merely provide background information related to the present disclosure and may not necessarily constitute prior art.
The hand is a very flexible and precise organ, has a motion joint with multiple degrees of freedom and a complex neuromuscular structure, and plays an irreplaceable role in daily life. However, the normal activities of the hands are seriously affected due to the aging of the human body, or hand function injuries and disorders caused by various diseases and accidents, etc., and the production efficiency and the quality of life of the patient are reduced. For example, stroke is one of the common diseases that lead to impaired hand function. Most cerebral apoplexy patients can be accompanied by loss of single-side hand functions, and more people adopt a method based on a wearable exoskeleton robot to help the patients to perform hand function rehabilitation training in consideration of the fact that the number of rehabilitation trainers is far from the requirement.
At present, the design and development of the wearable exoskeleton hand function robot are more, but the degree of freedom of most robots is lower, the rehabilitation training mode is single, and the effect cannot be very good; meanwhile, many hand function robots are uncomfortable to wear, and cannot be suitable for hand sizes of all patients, so that convenient and free wearing training cannot be achieved. So there is no related hand function robot capable of providing high degree of freedom and wearable hand function training with man-machine interaction function.
Disclosure of Invention
In order to solve the problems, the invention provides a multi-degree-of-freedom wearable exoskeleton hand function rehabilitation robot based on redundant control, which is characterized in that a connecting rod type hand function rehabilitation robot is designed, a finger connecting rod mechanism is fixed on a palm back platform, and connecting rods with multiple degrees of freedom are connected in a nested manner to realize the rotation and bending functions of fingers; in the process of grasping, the motion track is accurately estimated according to the fingertip position by adopting redundant control, and the fingertip force in the grasping process is accurately regulated by adopting a force feedback control method, so that the stability of the grasping process is improved.
In order to achieve the above purpose, the present invention adopts the following technical scheme:
in a first aspect, the present invention provides a redundancy control-based multi-degree-of-freedom wearable exoskeleton hand function rehabilitation robot, comprising: the device comprises a palmback platform, a finger link mechanism, a steering engine, a pressure sensor and a control module, wherein the finger link mechanism, the steering engine, the pressure sensor and the control module are arranged on the palmback platform;
the finger link mechanism comprises a finger platform and a multi-degree-of-freedom link, wherein the multi-degree-of-freedom link is provided with a plurality of joints, and each joint is driven by an independent steering engine; the finger platform is provided with a pressure sensor for detecting fingertip force in the process of grasping;
the control module simulates a fingertip movement track according to the target fingertip position, and controls the torque of the steering engine according to the fingertip movement track so as to drive the steering engine to rotate; and controlling and adjusting the torque and the rotation speed of the steering engine according to the difference value between the actual fingertip force and the target fingertip force and the difference value between the actual fingertip position and the target fingertip position.
Alternatively, the multi-degree of freedom link includes a finger link base, a first inter-finger link, a second inter-finger link, a third inter-finger link, and a fingertip link;
the bottom of the finger connecting rod is connected with the steering engine through a bevel gear, so that the finger connecting rod mechanism generates bending and stretching of metacarpophalangeal joints;
the first inter-finger connecting rod is sleeved on the bottom of the finger connecting rod to generate rotational freedom degree in the horizontal plane, so that the opening and the closing of the finger connecting rod mechanism are realized;
the second inter-finger connecting rod is sleeved on the first inter-finger connecting rod so as to realize bending and stretching of the proximal inter-finger joint;
the third inter-finger connecting rod is buckled on the second inter-finger connecting rod, and the rotational freedom degree in the horizontal plane is realized between the third inter-finger connecting rod and the second inter-finger connecting rod;
the fingertip connecting rod is sleeved on the third inter-finger connecting rod so as to realize bending of the coronal plane.
As an alternative embodiment, the finger platform is sleeved on the fingertip connecting rod to realize bending of the distal interphalangeal joint.
As an alternative implementation mode, the control module introduces joint movement impedance when planning the fingertip movement track, and constrains the movement of the connecting rod with multiple degrees of freedom through damping coefficients so as to meet the movement limit and the joint movement speed of each joint.
As an alternative embodiment, the finger link mechanism comprises an exoskeleton little finger, an exoskeleton ring finger, an exoskeleton middle finger, an exoskeleton index finger and an exoskeleton thumb, which are sequentially arranged at the corresponding positions of the palmar dorsum platform and are controlled by separate steering engines.
As an alternative implementation mode, the finger platform is fixedly provided with a circular ring sleeve, and the finger platform is fixedly arranged on the finger through the circular ring sleeve.
In a second aspect, the invention provides a control method of a multi-degree-of-freedom wearable exoskeleton hand function rehabilitation robot, comprising the following steps:
planning a fingertip movement track according to the target fingertip position, and controlling the torque of the steering engine according to the fingertip movement track so as to drive the steering engine to rotate;
and acquiring actual fingertip force and actual fingertip position in the grasping process, and controlling and adjusting the torque and the rotation speed of the steering engine according to the difference value of the actual fingertip force and the target fingertip force and the difference value of the actual fingertip position and the target fingertip position.
As an alternative implementation mode, joint motion impedance is introduced when a fingertip motion track is planned, and motion of the connecting rod with multiple degrees of freedom is restrained through damping coefficients so as to meet the motion limit and the joint motion speed of each joint.
As an alternative embodiment, the target fingertip position and target fingertip force are fingertip forces that ensure a complete fit of the fingertip to the fingertip position of the gripping object during gripping and complete gripping.
As an alternative implementation manner, the torque of the steering engine is controlled and adjusted according to the difference value between the actual fingertip force and the target fingertip force and the difference value between the actual fingertip position and the target fingertip position, and meanwhile, the difference value between the actual fingertip force and the target fingertip force is differentiated and then converted into the target rotation speed, so that the rotation speed of the steering engine is controlled and adjusted.
Compared with the prior art, the invention has the beneficial effects that:
the invention provides a redundant spatial position control-based connecting rod type multi-degree-of-freedom wearable exoskeleton hand function rehabilitation robot, which adopts redundant control to accurately estimate a motion track according to fingertip positions, adopts a force feedback control method to estimate and accurately adjust fingertip force in a grasping process, and improves stability of the grasping process; the finger tip of the user is completely contacted with the object, the touch perception capability of the finger tip is reserved, and the finger tip has important significance in clinical rehabilitation training of hand functions.
The invention designs the connecting rod type hand function rehabilitation robot based on the ergonomic principle and the daily behavioral analysis, five fingers are fixed on the palm back platform, the connecting rods are connected in a nested way, the rotation and bending functions of the fingers are realized, and the forefront end of the connecting rod is sleeved on the fingers by an annular structure, so that the influence on the touch perception of the finger tips is avoided. The connecting rod mechanism is fixed on the hand only at the finger tips, and is driven by adopting a redundant control mode with multiple degrees of freedom, so that the position of the finger tips can be accurately controlled, each finger contains 6 degrees of freedom, and the multifunctional finger is suitable for people with different finger lengths and is comfortable to wear.
According to the invention, the fingertip accurate position control based on the multi-degree-of-freedom redundant control is realized, the space track of fingertip movement is simulated according to the expected fingertip position, and the joint movement vector is converted into the connecting rod space movement vector, so that the torque of a steering engine at each joint of the connecting rod is calculated; in addition, the motion limit and the joint motion speed of each joint of a human hand are considered, and the human body damping coefficient is introduced to restrain the motion of the connecting rod; the integral controller is used for eliminating external disturbance, so that the robustness of a control system is enhanced, and the aim of accurate position control is fulfilled.
The invention adjusts fingertip force in real time based on a force feedback control algorithm. The fingertip position is estimated during the grip and the force of the fingertip at full grip to ensure that the fingertip is fully conformed to the object being gripped. The accurate fingertip force adjustment not only improves the sensing effect of the fingertip, but also ensures the grasping robustness.
Additional aspects of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
Drawings
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the invention.
Fig. 1 is an overall structure diagram of a multi-degree-of-freedom wearable exoskeleton hand function rehabilitation robot based on redundancy control provided in embodiment 1 of the present invention;
fig. 2 is a schematic view of a finger link mechanism according to embodiment 1 of the present invention;
FIG. 3 is a schematic diagram of redundant spatial position control based on fingertip force feedback according to embodiment 1 of the present invention;
FIG. 4 is a flow chart of redundant spatial position control based on fingertip force feedback provided in embodiment 1 of the present invention;
the device comprises a first finger, a second finger, a third finger, a finger tip connecting rod, a finger platform, a pressure sensor and a ring sleeve, wherein the first finger is a finger tip connecting rod, the second finger is a finger tip connecting rod, the third finger connecting rod is a finger tip connecting rod, the finger tip connecting rod is a finger platform, the pressure sensor is a finger platform, and the ring sleeve is a ring sleeve.
Detailed Description
The invention is further described below with reference to the drawings and examples.
It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the invention. 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 invention belongs.
It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular forms also are intended to include the plural forms, and furthermore, it is to be understood that the terms "comprises" and "comprising" and any variations thereof are intended to cover non-exclusive inclusions, such as, for example, processes, methods, systems, products or devices that comprise a series of steps or units, are not necessarily limited to those steps or units that are expressly listed, but may include other steps or units that are not expressly listed or inherent to such processes, methods, products or devices.
Embodiments of the invention and features of the embodiments may be combined with each other without conflict.
Example 1
As shown in fig. 1, this embodiment provides a multi-degree-of-freedom wearable exoskeleton hand function rehabilitation robot based on redundant control, including: the palm back platform 10, a finger link mechanism, a steering engine, a pressure sensor 19, a control module 9, a Bluetooth module 6 and a battery module 7 which are arranged on the palm back platform;
the finger linkage mechanism comprises a finger platform 18 and a multi-degree-of-freedom linkage, wherein the multi-degree-of-freedom linkage is provided with a plurality of joints, and each joint is driven by a separate steering engine; the finger platform 18 is provided with a pressure sensor 19 for detecting fingertip force in the process of gripping;
the control module 9 simulates a fingertip movement track according to the target fingertip position, and controls the torque of the steering engine according to the fingertip movement track so as to drive the steering engine to rotate; and controlling and adjusting the torque and the rotation speed of the steering engine according to the difference value between the actual fingertip force and the target fingertip force and the difference value between the actual fingertip position and the target fingertip position.
In the embodiment, based on an ergonomic principle and daily behavioral analysis, the multi-degree-of-freedom wearable exoskeleton hand function rehabilitation robot is designed to be a connecting rod type hand function robot, a finger connecting rod mechanism is fixed on a palm back platform, and connecting rods with multiple degrees of freedom are nested and connected to realize the rotation and bending functions of fingers;
specifically, the finger link mechanism is an exoskeleton finger, and comprises 5 exoskeleton little fingers 1, an exoskeleton ring finger 2, an exoskeleton middle finger 3, an exoskeleton index finger 4 and an exoskeleton thumb 5, which are sequentially arranged at corresponding positions of the palmar dorsum platform 10.
Preferably, each exoskeleton finger is independently controlled by a steering engine 8, and five steering engines are all arranged on the palmar dorsum platform 10.
In this embodiment, the five exoskeleton fingers have identical structures, as shown in fig. 2, and include a finger platform 18 and a multi-degree-of-freedom link, where the multi-degree-of-freedom link includes a finger link bottom 13, a first inter-finger link 14, a second inter-finger link 15, a third inter-finger link 16, and a fingertip link 17;
specifically, the finger connecting rod bottom 13 is connected with the steering engine 8 through two bevel gears 12, and the bevel gears 12 change the transmission direction so as to enable the finger connecting rod mechanism to generate bending and stretching of metacarpophalangeal joints;
the first inter-finger connecting rod 14 is sleeved on the finger connecting rod bottom 13 to generate rotational freedom degree in a horizontal plane so as to realize opening and closing of fingers;
the second inter-finger connecting rod 15 is sleeved on the first inter-finger connecting rod 14 so as to realize the bending and stretching functions of the proximal inter-finger joints;
the third inter-finger connecting rod 16 is buckled on the second inter-finger connecting rod 15, and a rotational degree of freedom exists between the third inter-finger connecting rod 16 and the second inter-finger connecting rod 15 in a horizontal plane;
the fingertip connecting rod 17 is sleeved on the third inter-finger connecting rod 16 so as to realize bending of the coronal plane;
the finger platform 18 is sleeved on the fingertip connecting rod 17 so as to realize the bending function of the distal interphalangeal joint.
Preferably, miniature steering engines 11 are arranged inside the connecting rods, so that the movement between the connecting rods is realized respectively.
It can be understood that the miniature steering engine can be adopted in the interior of the finger due to space limitation, and each finger connecting rod is inlaid with 5 miniature steering engines, and 25 miniature steering engines are inlaid in the interior of the finger to respectively control the motions of different finger joints.
It can be understood that each exoskeleton finger is independently controlled by a large steering engine, and 5 large steering engines are provided for respectively and independently controlling the exoskeleton fingers.
In this embodiment, a circular sleeve 20 is fixed on the finger platform 18, the finger platform 18 is attached to the back of the finger tip, and the finger platform is fixed on the finger through the circular sleeve 20.
Preferably, two circular sleeves 20 are provided on each finger platform 18, it being understood that the number of circular sleeves 20 would be provided by one skilled in the art depending on the actual need.
Preferably, a pressure sensor 19 is adhered to the finger platform 18, and is in close contact with the back of the finger.
In this embodiment, the bluetooth module 6 is used for wireless communication between the modules, so as to enhance portability of the device.
In this embodiment, the battery module 7 provides power to each module of the whole hand function rehabilitation robot.
Preferably, the control module 9 adopts a single-chip microcomputer, and can also adopt other types of controllers, and the control module can be selected by a person skilled in the art according to actual needs.
The multi-degree-of-freedom wearable exoskeleton hand function rehabilitation robot is designed to be a connecting rod type hand function robot based on an ergonomic principle and daily behavioral analysis, the finger connecting rod mechanisms are fixed on the palm back platform, the connecting rods with multiple degrees of freedom are connected in a nested mode, so that the rotation and bending functions of fingers are achieved, the relative positions of the five finger connecting rod mechanisms are similar to those of a human hand, the robot is fixed on the hand through palm back bandages and fingertips, and the robot is comfortable to wear, and does not affect normal movement of the human hand; each finger contains 6 degrees of freedom and is suitable for people with different finger lengths.
The foremost end of the connecting rod with multiple degrees of freedom is sleeved on the finger by adopting an annular structure, so that the influence on the touch perception of the finger tip is avoided; and the position of the fingertip is precisely controlled by adopting a multi-degree-of-freedom redundant control mode; meanwhile, the pressure value of the fingertip is measured through a pressure sensor arranged at the fingertip, and the fingertip force is adjusted in real time, so that the accurate adjustment of the fingertip force is realized.
In this embodiment, as shown in fig. 3-4, the fingertip position and fingertip force are adjusted in real time in the control module, so as to achieve the accuracy and stability of the fingertip in the grasping process. The control module plans the fingertip movement track according to the target fingertip position, converts fingertip position information into a control signal to drive the micro steering engine to rotate, but ensures the accuracy of fingertip movement, judges whether the fingertip reaches the expected position in real time, and drives the steering engine to further accurately adjust the fingertip position if the fingertip does not reach the expected position;
if the stability of the grip is ensured to better play a rehabilitation effect, the fingertip force needs to be evaluated, the grip object may be damaged if the fingertip force is too large, and slipping is easy to occur if the fingertip force is too small, so the fingertip force needs to be adjusted according to the data of the pressure sensor.
In order to improve accuracy and stability in the pressing process, the embodiment adopts a redundant spatial position control method based on fingertip force feedback aiming at uncertainty and unpredictable external interference of a model. The motion trail of the hand function rehabilitation robot is planned in an operation space of a human or robot system, a space trail of fingertip motion is simulated according to an expected fingertip position, an expected finger joint angle is obtained through the motion trail, and then a finger joint motion vector is converted into a connecting rod space motion vector, so that the torque of a steering engine at each joint is controlled. Thus, the space velocity vector v is manipulated d Is converted into (6 x 1) joint space vectors:
if the spatial trajectory of fingertip motion is simply randomly modeled with a mole-penrose inverse function, the proposed mathematical solution does not take into account joint motion limits; the inverse kinematics calculation requires additional constraints to meet the motion limits of each joint as well as the joint motion speed, taking into account the human hand joint motion impedance.
Therefore, this example introduces the Levenberg-Marquardt method (Levenberg-Marquardt-stability) to solve this problem:
in the embodiment, the damping coefficient lambda is introduced to restrict the movement of the connecting rod, so that the joint speed is reduced, and the wearing safety and comfort are ensured; the damping coefficient λ is calculated as follows:
wherein sigma n For the eigenvalues of Jacobian matrix J,for the rate of articulation of the finger +.>And epsilon are +.>Sum sigma n The specific value of the threshold value is determined by a simulation experiment; lambda (lambda) max The specific numerical value is determined by a simulation experiment for the maximum value of the damping coefficient lambda;
the damping coefficient lambda depends onSum sigma n If both values are greater than their threshold +.>And epsilon, lambda increaseAdded to lambda max Even if the exoskeleton performs random joint space trajectories due to the motion of the human user, the threshold value must be predefined. Eigenvalues sigma of jacobian matrix n The minimum value calculates the damping coefficient lambda, and simulation shows that not all characteristic values sigma n The near zero configuration results in high joint velocity, which means that the characteristic value near zero is not necessarily linked to high joint velocity.
In the inverse kinematics of the robot, the jacobian matrix cannot guarantee the rationality of the joint limits, so this embodiment uses the zero space of the redundant 6-degree-of-freedom hand function rehabilitation robot, making each joint as close to the middle position as possible, by optimizing:
for an ideal velocity vector in joint space, the desired joint space vector q is derived by inverse euler integration of equation (7):
wherein v is d A spatial velocity vector representing the finger tip,representing the joint space vector of the connecting rod, J is a Jacobian matrix, J T Is the transpose of the jacobian matrix, +.>Is the only solution of matrix transformation, representing the nearest approximation of the link space vector to the fingertip space velocity vector,/->Representing the joint space vector null space position.
The null-space optimization provides the opportunity for user interaction to change joint angles without changing TCP (tool center point) pose:
τ user ＝τ sens -τ exo ＝K 2 (8)
wherein τ user Is the torque generated by the hand movement and is the actual measured torque tau sens ，τ sens FxL, i.e. the pressure F detected by the pressure sensor force multiplied by the distance L, L being a fixed value, is the distance from the center point of the pressure sensor to the fingertip spindle;
the user intention is the actual measured torque and the torque tau provided by the hand function rehabilitation machine ginseng model when the fingertip is not loaded exo Difference between them. The joint moments of the robot system dynamics are derived from the gravity and inertia vectors of the moving elements and the friction vectors of the joints and the drive unit.
Modeling the joint torque caused by dynamics and measuring the interaction force, deriving the user's additional torque from the measured torque in each joint, and adding to equation (5):
wherein k is 1 And k 2 Is the gain factor for the joint limits and the user torque optimization criteria.
Thus, the null space optimizes the user's intent to change the position in joint space as it moves along a defined trajectory in the operating space.
In this embodiment, the fingertip force is adjusted in real time based on a force feedback control algorithm, and the fingertip position and the fingertip force at full grip are estimated during the grip process to ensure that the fingertip is fully attached to the gripped object. Calculating the equivalent moment tau at the joint Fe When the force difference is converted into the target force F d And actual force F e A difference between them;
for positioning τ pos Required thatIs defined as the total torque:
τ q ＝τ pos +τ Fe (10)
in order to control the hand function rehabilitation robot more stably, the embodiment provides hybrid force position control according to the actual position x e With the target position x d And the actual force F e With a target force F d The difference value is used for adjusting the moment provided by the steering engine and simultaneously differentiating and converting the force difference delta F into the target feeding speed, so as to adjust the rotating speed of the steering engine:
v x,d ＝k I ∫ΔFdt (11)
the present embodiment uses a gain factor k I Even in the case of sudden disturbances, the proportional component of the controller is distributed, enhancing the robustness of the control system.
When the hand function rehabilitation robot of the embodiment is adopted for training, a user wears the hand function rehabilitation robot first and fixes the hand function rehabilitation robot on the back of the hand by using a fixing bandage; then, a training mode and training time are set, wherein the training mode comprises a single-finger bending mode and a grasping mode, and the two modes are mixed to achieve a better effect on hand function rehabilitation training. The control module plans the movement track of the fingertip, converts the position information of the fingertip into control signals to drive each steering engine to rotate, and accurately controls the fingertip position to reach the expected target position; in the motion process, the rotation of the steering engine is fed back and regulated through the collected rotation angle information of the steering engine and the fingertip pressure information collected by the pressure sensor, so that the control is more accurate, the fingertip force is regulated according to the data of the force sensor, and the grasping stability is ensured. And when the set training time is reached, the hand function rehabilitation robot is taken down to complete rehabilitation training.
The hand function rehabilitation robot of the embodiment keeps the touch perception of fingertips and has important significance in the rehabilitation training of hand functions. The device can be used for rehabilitation training of patients with impaired hand functions such as cerebral apoplexy, can accurately perform fingertip control and grasping training, and has important values for human-computer interaction systems, rehabilitation therapy, perception movement function evaluation and the like.
While the foregoing description of the embodiments of the present invention has been presented in conjunction with the drawings, it should be understood that it is not intended to limit the scope of the invention, but rather, it is intended to cover all modifications or variations within the scope of the invention as defined by the claims of the present invention.
Claims (6)
1. Multi-degree-of-freedom wearable exoskeleton hand function rehabilitation robot based on redundant control, which is characterized by comprising: the device comprises a palmback platform, a finger link mechanism, a steering engine, a pressure sensor and a control module, wherein the finger link mechanism, the steering engine, the pressure sensor and the control module are arranged on the palmback platform;
the finger link mechanism comprises a finger platform and a multi-degree-of-freedom link, wherein the multi-degree-of-freedom link is provided with a plurality of joints, and each joint is driven by an independent steering engine; the multi-degree-of-freedom connecting rod comprises a finger connecting rod bottom, a first inter-finger connecting rod, a second inter-finger connecting rod, a third inter-finger connecting rod and a fingertip connecting rod; the bottom of the finger connecting rod is connected with the steering engine through a bevel gear, so that the finger connecting rod mechanism generates bending and stretching of metacarpophalangeal joints; the first inter-finger connecting rod is sleeved on the bottom of the finger connecting rod to generate rotational freedom degree in the horizontal plane, so that the opening and the closing of the finger connecting rod mechanism are realized; the second inter-finger connecting rod is sleeved on the first inter-finger connecting rod so as to realize bending and stretching of the proximal inter-finger joint; the third inter-finger connecting rod is buckled on the second inter-finger connecting rod, and the rotational freedom degree in the horizontal plane is realized between the third inter-finger connecting rod and the second inter-finger connecting rod; the fingertip connecting rod is sleeved on the third inter-finger connecting rod so as to realize bending of the coronal plane; the finger platform is provided with a pressure sensor for detecting fingertip force in the process of grasping; a circular ring sleeve is fixed on the finger platform, and the finger platform is fixed on the finger through the circular ring sleeve; the finger platform is sleeved on the fingertip connecting rod to realize bending of the distal interphalangeal joint;
the control module plans a fingertip movement track according to the target fingertip position, and controls the torque of the steering engine according to the fingertip movement track so as to drive the steering engine to rotate; controlling and adjusting the torque and the rotation speed of the steering engine according to the difference value between the actual fingertip force and the target fingertip force and the difference value between the actual fingertip position and the target fingertip position;
when the control module plans the fingertip movement track, joint movement impedance is introduced, and the movement of the connecting rod with multiple degrees of freedom is restrained through the damping coefficient so as to meet the movement limit and the joint movement speed of each joint.
2. The redundant control-based multi-degree of freedom wearable exoskeleton hand function rehabilitation robot of claim 1, wherein the finger link mechanism comprises an exoskeleton little finger, an exoskeleton ring finger, an exoskeleton middle finger, an exoskeleton index finger and an exoskeleton thumb, all of which are sequentially arranged at corresponding positions of the dorsum palmae platform and are controlled by separate steering engines.
3. A method for controlling a multi-degree-of-freedom wearable exoskeleton hand function rehabilitation robot according to any one of claims 1 to 2, comprising:
planning a fingertip movement track according to the target fingertip position, and controlling the torque of the steering engine according to the fingertip movement track so as to drive the steering engine to rotate;
and acquiring actual fingertip force and actual fingertip position in the grasping process, and controlling and adjusting the torque and the rotation speed of the steering engine according to the difference value of the actual fingertip force and the target fingertip force and the difference value of the actual fingertip position and the target fingertip position.
4. A control method according to claim 3, wherein the joint movement resistance is introduced when planning the fingertip movement trajectory, and the movement of the multi-degree-of-freedom link is constrained by the damping coefficient to meet the movement limit and the joint movement speed of each joint.
5. A control method according to claim 3, wherein the target fingertip position and target fingertip force are fingertip positions that ensure complete fitting of the fingertip to the gripped object during gripping and fingertip forces at complete gripping.
6. The control method according to claim 3, wherein the torque of the steering engine is controlled and adjusted according to the difference between the actual fingertip force and the target fingertip force and the difference between the actual fingertip position and the target fingertip position, and the difference between the actual fingertip force and the target fingertip force is differentiated and converted into the target rotational speed to control and adjust the rotational speed of the steering engine.
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