Disclosure of Invention
The invention aims to provide a saw blade bending measurement method, a correction method of a surgical robot and the surgical robot, wherein the relationship between a pressure change value of a pressure sensor and a corresponding bending value of the saw blade can be obtained, the pressure born by the saw blade is obtained in real time through the pressure sensor when a follow-up surgical robot performs surgery, the bending error of the saw blade can be calculated and obtained based on the relationship between the pressure change value of the pressure sensor and the corresponding bending value of the saw blade, prompt early warning can be performed in real time, the bending error can be corrected through controlling a cooperative mechanical arm in the surgical robot, the probability of occurrence of surgical accidents is reduced, the precision of surgery is improved, and the success rate of surgery is facilitated to be improved.
In order to achieve the above purpose, the invention provides a saw blade bending measurement method, two pressure sensors are respectively arranged on two sides of a fixing position of a bone saw and a saw blade, the two pressure sensors are positioned on the same plane of the saw blade and are in contact with the saw blade, the method comprises the steps of controlling a tracking pressure probe to apply continuously-changing pressure to one end, far away from the pressure sensors, of the plane, and obtaining pressure values acquired by the pressure sensors with changed values and the space positions of the saw blade recorded by the corresponding tracking pressure probes, and obtaining the relation between the pressure change values of the pressure sensors and the space position change values of the corresponding saw blade based on the pressure values acquired by the pressure sensors and the space positions of the saw blade recorded by the corresponding tracking pressure probes for each pressure sensor.
The invention further provides a correction method of the surgical robot, two pressure sensors are respectively arranged on two sides of a position where a bone saw and a saw blade are fixed, the two pressure sensors are located on the same plane of the saw blade and are in contact with the saw blade, the method comprises the steps of acquiring pressure values acquired by the two pressure sensors in real time in the working process of the surgical robot, acquiring the current spatial position change value of the saw blade corresponding to the current pressure change value of the pressure sensor based on the preset relation between the pressure change value of the pressure sensor and the spatial position change value of the saw blade for the pressure sensor, wherein the relation between the pressure change value of the pressure sensor and the spatial position change value of the saw blade is obtained based on the saw blade bending measurement method, and correcting the spatial position of the saw blade based on the current spatial position change value of the saw blade.
The invention further provides a surgical robot, which comprises a control device, a cooperative mechanical arm, a bone saw, a saw blade and two pressure sensors, wherein the control device is in communication connection with the cooperative mechanical arm and the two pressure sensors respectively, the bone saw is fixed on the cooperative mechanical arm, the saw blade is fixed on the bone saw, the two pressure sensors are respectively arranged on two sides of a fixing position of the bone saw and the saw blade, the two pressure sensors are located on the same plane of the saw blade and are in contact with the saw blade, and the control device is used for executing the correction method of the surgical robot.
In the embodiment of the invention, at each plane of the saw blade, a tracking pressure probe is controlled to apply continuously-changing pressure to one end of the plane far away from the pressure sensor, and a pressure value acquired by the pressure sensor with a changed value and a corresponding spatial position of the saw blade recorded by the tracking pressure probe are acquired, namely, the external force born by the saw blade during the work is simulated by the tracking pressure probe, and the pressure and the bending value of the saw blade are recorded by the pressure sensor, so that the two planes of the saw blade can be subjected to pressure, and the two planes of the saw blade can be respectively subjected to two-time pressure application tests; and then, for each pressure sensor, based on the pressure value acquired by the pressure sensor and the corresponding spatial position of the saw blade recorded by the tracking pressure probe, obtaining the relation between the pressure change value of the pressure sensor and the corresponding spatial position change value of the saw blade, namely solving the relation between the pressure change value of the pressure sensor and the corresponding bending value of the saw blade by using the recorded pressure and the bending value of the saw blade, and when the saw blade in the subsequent operation robot performs an operation, acquiring the pressure born by the saw blade in real time by the pressure sensor, and based on the relation between the pressure change value of the pressure sensor and the corresponding bending value of the saw blade, calculating the bending error of the saw blade, performing prompt early warning in real time, correcting the bending error by controlling a cooperative mechanical arm in the operation robot, reducing the occurrence probability of the operation accident, improving the accuracy of the operation and being beneficial to improving the success rate of the operation.
In one embodiment, for each pressure sensor, based on the pressure value acquired by the pressure sensor and the spatial position of the saw blade recorded by the corresponding tracking pressure probe, obtaining the relationship between the pressure change value of the pressure sensor and the spatial position change value of the corresponding saw blade comprises establishing a relational expression between the pressure change value of the pressure sensor and the spatial position change value of the saw blade recorded by the corresponding tracking pressure probe for each pressure sensor, and solving the relational expression between the pressure change value of the pressure sensor and the spatial position change value of the saw blade recorded by the corresponding tracking pressure probe based on the recorded pressure value of the pressure sensor and the spatial position of the saw blade recorded by the corresponding tracking pressure probe for each pressure sensor.
In one embodiment, the relationship between the pressure change value of the pressure sensor and the corresponding spatial position change value of the saw blade recorded by the tracking pressure probe is:
ΔNi＝a·Δdi2+b·Δdi+c;
ΔNi＝Ni-N0;
Δdi＝dis(Pi,P0);
Wherein Δni represents an i-th pressure change value of the pressure sensor, Ni represents an i-th pressure value of the pressure sensor, N0 represents an initial pressure value of the pressure sensor, Δdi represents an i-th spatial position change value of the saw blade recorded by the tracking pressure probe, Pi represents an i-th spatial position of the saw blade recorded by the tracking pressure probe, P0 represents an initial spatial position of the saw blade recorded by the tracking pressure probe, i=1, 2, 3..n, N is a total number of recorded data, and a, b, c are all parameters to be solved.
In one embodiment, the initial pressure value of the pressure sensor is the pressure value of the pressure sensor when the pressure sensor is in contact with the saw blade.
In one embodiment, the tracking pressure probe records the initial spatial position of the saw blade while the tracking pressure probe is in contact with the plane of the saw blade and the two pressure sensors maintain initial pressure values.
In one embodiment, the solving of the relation between the pressure change value of the pressure sensor and the spatial position change value of the saw blade recorded by the corresponding tracking pressure probe based on the recorded pressure value of the pressure sensor and the spatial position of the saw blade recorded by the corresponding tracking pressure probe for each pressure sensor comprises solving the relation between the pressure change value of the pressure sensor and the spatial position change value of the saw blade recorded by the corresponding tracking pressure probe based on the recorded pressure value of the pressure sensor and the spatial position of the saw blade recorded by the corresponding tracking pressure probe by using a least square method.
In one embodiment, the direction in which the control tracking pressure probe applies a continuously varying pressure to the plane is perpendicular to the plane of the saw blade.
Detailed Description
The following detailed description of various embodiments of the present invention will be provided in connection with the accompanying drawings to provide a clearer understanding of the objects, features and advantages of the present invention. It should be understood that the embodiments shown in the drawings are not intended to limit the scope of the invention, but rather are merely illustrative of the true spirit of the invention.
In the following description, for the purposes of explanation of various disclosed embodiments, certain specific details are set forth in order to provide a thorough understanding of the various disclosed embodiments. One skilled in the relevant art will recognize, however, that an embodiment may be practiced without one or more of the specific details. In other instances, well-known devices, structures, and techniques associated with the present application may not be shown or described in detail to avoid unnecessarily obscuring the description of the embodiments.
Throughout the specification and claims, unless the context requires otherwise, the word "comprise" and variations such as "comprises" and "comprising" will be understood to be open-ended, meaning of inclusion, i.e. to be interpreted to mean "including, but not limited to.
Reference throughout this specification to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, appearances of the phrases "in one embodiment" or "in an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.
As used in this specification and the appended claims, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. It should be noted that the term "or" is generally employed in its sense including "or/and" unless the context clearly dictates otherwise.
In the following description, for the purposes of clarity of presentation of the structure and manner of operation of the present invention, the description will be made with the aid of directional terms, but such terms as "forward," "rearward," "left," "right," "outward," "inner," "outward," "inward," "upper," "lower," etc. are to be construed as convenience, and are not to be limiting.
A first embodiment of the present invention relates to a method for measuring a bending degree of a saw blade in a surgical robot, such as a knee replacement surgical robot, to correct the bending of the saw blade in real time during a surgical operation of the surgical robot. In the surgical robot, a bone saw is arranged on a cooperative mechanical arm, a saw blade is fixed on the bone saw, two pressure sensors are respectively arranged on two sides of a fixed position of the bone saw and the saw blade, and the two pressure sensors are positioned on the same plane of the saw blade and are contacted with the saw blade. Referring to fig. 1, a saw blade 1 is fixed on a bone saw 2, the bone saw 2 has a limiting portion 21, the limiting portion 21 is used for limiting the saw blade 1, two pressure sensors are arranged along the length direction of the saw blade, the two pressure sensors are respectively arranged at two sides of the limiting portion 21, the pressure sensor arranged at the left side of the limiting portion 21 is denoted as a pressure sensor 31, the pressure sensor arranged at the right side of the limiting portion 21 is denoted as a pressure sensor 32, and the two pressure sensors may be arranged perpendicular to the plane of the saw blade 1.
A specific flow of the method for measuring the bending of the saw blade according to the present embodiment is shown in fig. 2.
And 101, controlling the tracking pressure probes to apply continuously-changing pressure to one end of the plane far away from the pressure sensor on each plane of the saw blade, and acquiring the pressure value acquired by the pressure sensor with the changed value and the spatial position of the saw blade recorded by the corresponding tracking pressure probes.
Step 102, for each pressure sensor, based on the pressure value collected by the pressure sensor and the spatial position of the saw blade recorded by the corresponding tracking pressure probe, obtaining the relation between the pressure change value of the pressure sensor and the spatial position change value of the corresponding saw blade.
In one example, referring to fig. 3, step 102 includes the following sub-steps:
In a substep 1021, for each pressure sensor, a relationship is established between the pressure change value of the pressure sensor and the spatial position change value of the saw blade recorded by the corresponding tracking pressure probe.
Specifically, the relation between the pressure change value of the pressure sensor and the spatial position change value of the saw blade recorded by the corresponding tracking pressure probe is as follows:
ΔNi＝a·Δdi2+b·Δdi+c;
ΔNi＝Ni-n0;
Δdi＝dis(Pi,P0);
Wherein Δni represents the i-th pressure change value of the pressure sensor, Ni represents the i-th pressure value of the recorded pressure sensor, N0 represents the initial pressure value of the pressure sensor, Δdi represents the i-th spatial position change value of the saw blade recorded by the tracking pressure probe, Pi represents the i-th spatial position of the saw blade recorded by the tracking pressure probe, P0 represents the initial spatial position of the saw blade recorded by the tracking pressure probe, i=1, 2, 3.
In sub-step 1022, for each pressure sensor, a relationship between the pressure change value of the pressure sensor and the spatial position change value of the saw blade recorded by the corresponding tracking pressure probe is solved based on the recorded pressure value of the pressure sensor and the spatial position of the saw blade recorded by the corresponding tracking pressure probe.
The method for measuring the bending of the saw blade in this embodiment will be described in detail.
After the saw blade 1 is mounted on the bone saw 2, and after two pressure sensors (including the pressure sensor 31 and the pressure sensor 32) are in contact with the plane of the saw blade 1, the two pressure sensors may be disposed perpendicular to the plane of the saw blade 1, so that the pressure sensors can receive the acting force perpendicular to the plane of the saw blade 1, that is, the pressure sensors can collect the pressure of the contact surface between the plane and the pressure sensors, and the pressure sensors are connected to a control device (such as a computer host, a tablet computer, and an electronic device such as a mobile phone) of the surgical robot and send the collected pressure to the control device. Wherein, the control device takes the current pressure value acquired by the two pressure sensors as the initial pressure value of the two pressure sensors under the condition that the saw blade 1 is arranged on the bone saw 2, the bone saw is kept motionless and cooperatively and mechanically locked, and the initial pressure value of the pressure sensor 31 is thatThe initial pressure value of the pressure sensor 32 is
The control device uses the mechanical arm to drive the tracking pressure probe to apply a continuously changing pressure on the end of the saw blade 1 remote from the pressure sensor in two times to simulate the upward bending or downward bending of the saw blade 1 when being stressed.
Referring to fig. 4, taking an example of testing the upper plane of the saw blade 1 by the tracking pressure probe 4, the control device controls the mechanical arm to drive the tracking pressure probe 5 to contact with one end of the upper plane of the saw blade 1 far away from the pressure sensor, the tracking pressure probe 4 is provided with a tracker for acquiring the space position of the tracking pressure probe, when the tracking pressure probe 4 is completely contacted with the upper plane of the saw blade 1 and the values of the two pressure sensors are unchanged and still are initial pressure values, the tracker takes the acquired space position of the tracking pressure probe 4 as an initial space position P0(x0,y0,z0 thereof, and at the moment, the tracking pressure probe 4 does not apply pressure to the saw blade 1, so that the initial space position P0(x0,y0,z0) of the tracking pressure probe is the initial space position of the saw blade 1.
Subsequently, the control device controls the mechanical arm to drive the tracking pressure probe 4 to apply a continuously varying pressure (for example, a continuously increasing pressure) to the upper plane of the saw blade 1, controls the direction in which the continuously varying pressure is applied to the plane by the tracking pressure probe 4 to be perpendicular to the plane of the saw blade, and when the downward pressure is applied to the upper plane of the saw blade 1 by the tracking pressure probe 4, the saw blade 1 bends downward, the greater the pressure is applied to the upper plane of the saw blade 1 by the tracking pressure probe 4, the greater the bending degree of the saw blade 1, the real-time recording of the spatial position of the tracking pressure probe 4 by the tracking pressure probe 4, i.e., the recording of the spatial position Pi(xi,yi,zi of the saw blade 1, i=1, 2..n, and the real-time transmission of the spatial position Pi(xi,yi,zi) of the saw blade 1 to the control device.
Based on the fixing mode of the saw blade 1 and the bone saw 2, when the saw blade 1 is bent downwards and deformed, the part of the saw blade 1 on the right side of the limiting part 21 is bent upwards, at the moment, the value of the pressure sensor 32 is changed, the value of the pressure sensor 31 is not changed, the pressure applied by the tracking pressure probe 4 to the upper plane of the saw blade 1 is continuously changed, the pressure value acquired by the pressure sensor 32 is also continuously changed, and the pressure sensor 32 acquires the pressure value according to the preset acquisition frequency to obtainAnd the acquired pressure valueAnd sending the information to the control device, wherein the tracker and the pressure sensor 32 acquire information according to the same frequency, namely the tracker and the pressure sensor 32 acquire information at the same time and send the information to the control device. If the pressure collected by the pressure sensor 32 forms a certain angle with the upper plane of the saw blade 1, the force perpendicular to the upper plane of the saw blade 1 can be calculated and sent to the control device as the pressure value detected by the pressure sensor 32.
When the control device receives n data messages sent by the tracker and the pressure sensor 32, the control device defines the pressure change value of the pressure sensor 32 asWherein,Indicating the ith pressure change value of the pressure sensor 32,Representing the i-th pressure value of the recorded pressure sensor 32,The initial pressure values of the pressure sensor are indicated, i=1, 2,3,..n, n being the total number of data recorded.
The spatial position variation value of the saw blade 1 is defined as deltadi,Where Δdi denotes the i-th spatial position change value of the saw blade recorded by the tracking pressure probe, Pi denotes the i-th spatial position of the saw blade recorded by the tracking pressure probe, the coordinates are denoted (xi,yi,zi),P0 denotes the initial spatial position of the saw blade recorded by the tracking pressure probe, the coordinates are denoted (x0,y0,z0), i=1, 2, 3..and n, n is the total number of recorded data.
A relation between the pressure change value of the pressure sensor 32 and the corresponding change value of the spatial position of the saw blade 1 recorded by the tracking pressure probe is established, specifically as follows:
Wherein a, b and c are parameters to be solved.
The above relation can then be solved based on the pressure change values of the n pressure sensors 32 and the spatial position change values of the n saw blades 1, for example, by a least square method, specifically as follows:
The objective function is:
the linear regression model is defined as hi(x1,x2)＝c+b·x1,i+a·x2,i;
wherein, x1,i＝Δdi is the total number of the components,
Substituting n samples Δdi into the linear regression model can result in:
h1＝c+b·x1,1+a·x2,1
h2＝c+b·x1,2+a·x2,2
......
hn＝c+b·x1,n+a·x2,n
let x0 =1, the above equation can be converted into a matrix representation:
h=DL
wherein h is a vector of nx1, represents a theoretical value of a linear regression model, D is a matrix of nx3 dimensions, n represents the number of samples, L is a vector of 3x1, and represents a vector consisting of c, b and a to be solved.
The objective function is represented by a matrix:
||h-Y||2＝||DL-Y||2＝(DL-Y)T(DL-Y)
Wherein Y represents nA one-dimensional vector is formed.
Simplifying the objective function of matrix representation:
(DL-Y)T(DL-Y)＝LTDTDL-LTDTY-YTDL+YTY
And deriving the simplified objective function to be equal to 0.
2DTDL-2DTY=0
Further, l= (DTD)-1DT Y) is solved.
Then n are addedAnd n Δdi are substituted into the above formula L, so that L can be obtained, namely, the values of three parameters a, b and c are obtained, thereby obtaining a relational expression between the pressure change value of the pressure sensor 32 and the spatial position change value of the saw blade 1 recorded by the corresponding tracking pressure probe 4, and the pressure change value of the pressure sensor 32 when the upper plane of the saw blade 1 is subjected to pressure is shown in FIG. 5A schematic diagram of the relationship between the change in the spatial position Δdi of the saw blade 1 recorded by the corresponding tracking pressure probe 4.
The test of the upper plane of the saw blade 1 by the trace pressure probe 4 in fig. 4 is described as an example, and similarly, the test of the lower plane of the saw blade 1 by the trace pressure probe 4 can be controlled in the same manner as the above process, and the value of the pressure sensor 3 is changed to obtain the pressure change value of the pressure sensor 31Relation between the values of the spatial position variation of the saw blade 1 recorded by the corresponding tracking pressure probe 4Wherein e, f and j are three parameters obtained by solution, and are the pressure change value of the pressure sensor 31 when the lower plane of the saw blade 1 is pressed as shown in FIG. 6A schematic diagram of the relationship between the change in the spatial position Δdi of the saw blade 1 recorded by the corresponding tracking pressure probe 4.
In the embodiment, a tracking pressure probe is controlled to apply continuously-changing pressure to one end of a plane far away from a pressure sensor on each plane of the saw blade, and a pressure value acquired by the pressure sensor with changing values and a spatial position of the saw blade recorded by the corresponding tracking pressure probe are acquired, namely, the pressure sensor is utilized to record the pressure and the bending value of the saw blade when the saw blade is simulated to work, as the two planes of the saw blade can be subjected to pressure, the two planes of the saw blade can be respectively subjected to two-time pressure application tests, then for each pressure sensor, the relation between the pressure value acquired by the pressure sensor and the spatial position of the saw blade recorded by the corresponding tracking pressure probe is acquired, namely, the relation between the pressure value of the pressure sensor and the bending value of the saw blade is acquired by utilizing the recorded pressure and the bending value of the saw blade, and the pressure sensor is utilized to calculate the error of the saw blade when the operation is performed, the error of the saw blade can be corrected in real time, and the error of the operation can be controlled by the error of the error warning robot is improved.
A second embodiment of the present invention relates to a calibration method for a surgical robot, which is applied to a control device of the surgical robot, wherein two pressure sensors are respectively disposed at two sides of a fixing position of a bone saw and a saw blade, and the two pressure sensors are located on the same plane of the saw blade and are in contact with the saw blade, as shown in fig. 1.
A specific flow of the correction method of the surgical robot according to the present embodiment is shown in fig. 7.
Step 201, acquiring pressure values acquired by two pressure sensors in real time during the operation of the surgical robot.
Step 202, for a pressure sensor with a pressure value changed, acquiring a current spatial position change value of the saw blade corresponding to the current pressure change value of the pressure sensor based on a preset relationship between the pressure change value of the pressure sensor and the spatial position change value of the saw blade, wherein the relationship between the pressure change value of the pressure sensor and the spatial position change value of the saw blade is obtained based on the saw blade bending measurement method in the first embodiment.
Step 203, correcting the spatial position of the saw blade based on the current spatial position change value of the saw blade.
Specifically, the control device of the surgical robot is preset with a relationship between the pressure change values of the two pressure sensors and the spatial position change value of the saw blade, that is, the control device is preset with a corresponding relationship between the pressure change value of each pressure sensor and the bending value of the saw blade.
In the process of performing bone sawing operation by the saw blade of the operation robot, the two pressure sensors can collect pressure in real time and send the collected current pressure value to the control device, and the two pressure sensors respectively reflect the pressure born by two planes of the saw blade, so that the bending of the saw blade in two directions perpendicular to the saw blade can be respectively corrected.
Taking the pressure sensor 32 in fig. 1 as an example, the control device of the surgical robot presets the relationship between the pressure change value of the pressure sensor 32 and the spatial position change value of the saw blade 1, namely, the relationship between the pressure change value of the pressure sensor 32 and the spatial position change value of the saw blade 1 recorded by the corresponding tracking pressure probe 4
For the current pressure value sent by the pressure sensor 32, the control device 1 compares the current pressure value sent by the pressure sensor 32 with the preset initial pressure value of the pressure sensor 32 to calculate a current pressure change value, and then substitutes the current pressure change value into the above relationThe spatial position change value of the saw blade 1 corresponding to the current pressure change value is obtained, the bending value of the saw blade 1 is equivalent to the bending error generated by the acting force of the bone on which the saw blade is subjected, then the control device controls the cooperative mechanical arm to drive the bone saw 2 to correct the spatial position of the saw blade 1 so as to compensate the current bending error of the saw blade 1, the running accuracy of the saw blade 1 is improved, and the adverse effect of the bending error of the saw blade 1 on an operation is counteracted.
In this embodiment, when performing the operation, the saw blade in the operation robot acquires the pressure that the saw blade received through pressure sensor in real time to based on the relation between the pressure variation value of presupposition pressure sensor and the crooked numerical value of corresponding saw blade, alright calculate the crooked error that obtains the saw blade, carry out the suggestion early warning in real time, and can correct crooked error through the collaborative mechanical arm in the control operation robot, reduce operation accident probability, improved the accuracy of operation, help promoting the success rate of operation.
A third embodiment of the present invention relates to a surgical robot, for example, a knee joint replacement surgical robot, please refer to fig. 1, 8 and 9, which includes a saw blade 1, a bone saw 2, two pressure sensors, a control device 5 and a cooperative mechanical arm 6, wherein the control device is an electronic device such as a computer host, a tablet computer, a mobile phone, etc., the control device 5 is respectively in communication connection with the cooperative mechanical arm 6 and the two pressure sensors (for example, through data lines), the bone saw 2 is fixed on the cooperative mechanical arm 6, the saw blade 1 is fixed on the bone saw 2, the two pressure sensors are respectively arranged at two sides of a fixing position of the bone saw 2 and the saw blade 2, and the two pressure sensors are located on the same plane of the saw blade 1 and are in contact with the saw blade 1. In fig. 9, only a part of the structure of the cooperative mechanical arm 6 is schematically shown, the cooperative mechanical arm 6 and the bone saw 2 are connected through a passive two-bar linkage, the bone saw 2 is provided with a limiting part 21, the limiting part 21 is used for limiting the saw blade 1, two pressure sensors are respectively arranged on two sides of the limiting part 21, the pressure sensor arranged on the left side of the limiting part 21 is denoted as a pressure sensor 31, the pressure sensor arranged on the right side of the limiting part 21 is denoted as a pressure sensor 32, and the two pressure sensors can be arranged to be perpendicular to the plane of the saw blade 1.
The control device 5 is used to perform the correction method of the surgical robot in the second embodiment.
While the preferred embodiments of the present invention have been described in detail above, it should be understood that aspects of the embodiments can be modified, if necessary, to employ aspects, features and concepts of the various patents, applications and publications to provide yet further embodiments.
These and other changes can be made to the embodiments in light of the above detailed description. In general, in the claims, the terms used should not be construed to be limited to the specific embodiments disclosed in the specification and the claims, but should be construed to include all possible embodiments along with the full scope of equivalents to which such claims are entitled.