Disclosure of Invention
The invention aims to provide a track prediction control method for a master-slave surgical robot, which solves the problems of delay and low precision of the tail end operation of the master-slave surgical robot.
The technical scheme adopted by the invention is a master-slave mode surgical robot track prediction control method, which is implemented according to the following steps:
step 1, designing a least square support vector machine Kalman vibration filtering algorithm, and filtering tremor signals of hands to obtain target track signals;
step 2, respectively carrying out trajectory planning on the target trajectory signal by a linear trajectory planning method and a Chebyshev pseudo-spectrum method to obtain a planned trajectory, and optimizing the planned trajectory by a quadratic planning method to obtain an actual trajectory signal;
and 3, mapping the motion poses of the master hand and the slave hand by taking the actual track signal as input through a master-slave pose mapping function, and realizing the prediction control of the track of the master-slave surgical robot.
The invention is also characterized in that:
the step 1 specifically comprises the following steps:
step 1.1, collecting the running track of a master hand, carrying out discretization calibration on the running track, and writing a Kalman filtering process into a state equation and a measurement process:
and (3) state process:
X(k)=AX(k-1)+w(k) (1),
the measurement process comprises the following steps:
Z(k)=HX(k)+v(k) (2),
in the formulas (1) and (2), x (k) is the state of the vibration signal in the main hand, the matrix a represents the state change, the vector z (k) is the signal measurement result, the matrix H represents the measurement change, the vector w (k) is the state noise, and the vector v (k) is the measurement noise, wherein w (k) and v (k) are gaussian white noises with the average value of 0, which are assumed to be independent of each other;
step 1.2, prediction
Predicting the value of the next time state according to the estimation value of the previous time state to become prior estimation, and predicting the error of the next time state to become prior error:
P(k|k-1)=AP(k-1|k-1)AT+Q (4),
in the formulas (3) and (4),
the state vector at time k is estimated from time k-1,
is the a posteriori estimated state vector at time k-1, P (k | k-1) is the covariance at time k estimated from time k-1, P (k-1| k-1) is the a posteriori estimated covariance at time k-1, Q is the process noise covariance;
step 1.3, update correction
Firstly, calculating Kalman gain, then calculating posterior estimation by using the prior estimation in the step 1.2, and simultaneously updating the prior error to the posterior error:
K(k)=P(k|k-1)HT[HP(k|k-1)HT+R]-1 (5),
P(k|k)=(I-K(k)H)P(k|k-1) (7),
in the formulae (5), (6) and (7),
the state vector at the time of updating k is predicted from the estimated state vector, and P (k | k) is predicted from the estimated state vectorCovariance at time k, I is the identity matrix, k (k) is the kalman gain at time k, R is the measurement noise covariance;
step 1.4, establishing regression equations of R and Q by adopting a least square support vector machine regression algorithm, and processing process noise and measurement noise;
and step 1.5, substituting the regression equation of the process noise covariance Q and the measurement noise covariance R in the step 1.4 into the step 1.2 and the step 1.3 to obtain an improved Kalman vibration filtering algorithm, and filtering the tremor signal of the hand to obtain a target track signal.
The step 1.4 is specifically as follows:
step 1.4.1, establishing a least square support vector machine training set of
Wherein S
i∈R
nIs a mixture of the measured vibration signal and the ideal control signal, as an input vector, R
iE, R is the covariance of the measurement noise of the vibration signal in the mixed signal;
step 1.4.2, according to the least square support vector machine theory, converting the regression problem of the nonlinear function of R and Q into the regression problem of the linear function, mapping variables R and Q into a high-dimensional space F, and obtaining the nonlinear function:
R(k)=ωTΦ(s)+bω∈F,b∈R (8),
in the formula (8), phi(s) is a nonlinear mapping function, and omega and b are undetermined parameters;
step 1.4.3, the optimization problem of the least squares support vector machine is defined according to step 1.4.2:
Ri=ωTΦ(Si)+b+ei i=1,...,N (10),
in formulae (9) and (10), eiIs the relaxation variable at time i, C is a constant greater than 0, and equation (10) is the constraint bar of equation (9)A member;
step 1.4.4, list lagrangian functions according to step 1.4.3:
in the formula (11), αiE, R, i 1, N, is a lagrange parameter;
step 1.4.5, for the general optimization problem with equality constraint in step 1.4.3, KKT gives the necessary condition for judging whether the solution value is the optimal solution, and calculates the partial derivative for all parameters of the lagrangian function listed in step 1.4.4;
step 1.4.6, set forth the system of linear equations for step 1.4.5:
in the formula (12), the reaction mixture is,
R=[R
1,...,R
N]
T,α=[α
1,...,α
N]
TΩ is the kernel matrix;
Ωij=φ(si)Tφ(sj)=K(si,sj) i,j=1,...,N (13),
in formula (13), K(s)i,sj) Is a kernel function, ΩijIs a kernel matrix of i rows and j columns;
step 1.4.7, solving the formula (12) to obtain the coefficient of the regression equation, namely obtaining the regression equation of the least square support vector machine for measuring the noise covariance R:
step 1.4.8, establishing a regression equation of the process noise covariance Q using steps 1.4.5 and 1.4.6, specifically:
in formulae (14) and (15) < alpha'iIs relative to aiLagrange parameter of (g), K(s)i,sj) Is relative to K(s)i,sj) B' is the pending parameter relative to b.
The step 2 specifically comprises the following steps:
step 2.1, carrying out track planning on the target track signal in a task space by a linear track planning method;
step 2.2, carrying out trajectory planning on the target trajectory signal in the joint space by a Chebyshev pseudo-spectrum method;
and 2.3, performing time-smoothness optimization on the tracks planned in the step 2.1 and the step 2.2 by a quadratic programming method to obtain an actual track signal.
The step 2.1 specifically comprises the following steps:
firstly, the position vector and the attitude vector of the mobile mechanical arm terminal point motion at the starting point and the terminal point of a task space are respectively represented as:
P
1=[x
1,y
1,z
1]
T、P
2=[x
2,y
2,z
2]
T、
the position vector and the attitude vector connecting the initial point and the target point are respectively:
P12=P2-P1=(x1-x2,y1-y2,z1-z2)T (16),
in the formulae (16) and (17), [ x, y, z]And
representing a position vector and a posture vector of a terminal point of a mobile mechanical arm under a task space coordinate system;
assuming that it takes time T from the initial value movement to the target value of the end point of the mobile manipulator, and then discretizing the position vector and the attitude vector, the position vector and the attitude vector of the end point of the mobile manipulator at the time T can be calculated:
in the formulae (18), (19), PtAnd RtFor the position vector and attitude vector at time t,
t denotes the time, te (t)
1,t
2) V and ω represent the average linear velocity and the average angular velocity from the initial value to the target value at the end point of the hand arm, respectively.
The step 2.2 specifically comprises the following steps:
step 2.2.1, time intervals are changed
The Chebyshev pseudo-spectrum method is a track approximately approximating state and control based on interpolation polynomial, wherein Chebyshev-Gauss-Lobatto points are selected as nodes and defined in an interval of [ -1, 1]Introducing a new time variable tau epsilon-1, 1]The original time interval [ t ]0,tf]Conversion to [ -1, 1 [ ]]And t is expressed as:
step 2.2.2 calculation of discrete nodes
Chebyshev polynomial T selected from discrete nodes by Chebyshev pseudo-spectrum methodN(t)=cos(Ncos-1(t)) the extreme point, i.e. the CGL point;
step 2.2.3 interpolation approximation of state variables and control variables
Firstly, taking N +1 discrete points, and constructing a Lagrange interpolation polynomial as an approximate value of a continuous state and a control variable, wherein an approximate expression of the continuous state x (tau) and the control variable u (tau) is as follows:
in the formulae (21) and (22), xjIs the state at time j, ujIs the control variable at time j, wherejIs the lagrange interpolation basis function;
step 2.2.4, processing of dynamic constraints
The derivative of the formula (21) gives a continuous state at τ
kDerivative at point
The approximate expression is:
in the formula (23), DkjIs (N +1) × (N +1) differential matrix D row k, column j element;
obtained by formula (23)
Instead of the state variable derivative with respect to time and discretizing at the interpolation nodes, the differential equation constraints of the original optimal control problem can be transformed into algebraic constraints, i.e. for
k 0, 1.
In the formula (24), x (τ)k) Time continuous state, u (τ)k) Is a control variable, τkIs the CGL point, τfAnd τ0Is a new time variable;
step 2.2.5, approximate calculation of performance index integrals
The Clenshaw-Curtis numerical integration is adopted to carry out approximate calculation on the integral term in the optimized performance index, and for any continuous function p (t) in the range of [ -1, 1], the integral can be approximately calculated by adopting the accumulation of function values at N +1 CGL discrete points, namely
In the formula (25), ωk(k ═ 0, 1.., N) is the Clenshaw-Curtis integration weight.
The step 2.3 is specifically as follows:
step 2.3.1, establishing constraint conditions of optimization model
Firstly, in order to operate safety, a position of a joint of a slave manipulator arm is generally limited by a stopper, and in order to avoid exceeding a joint movement range, a joint track is subjected to position constraint, which is specifically expressed as follows:
θmin≤θ(t)≤θmax (26),
in the formula (26), θ (t) and θminAnd thetamaxThe minimum value and the maximum value of the joint angle and the joint rotatable angle are respectively;
because the motor and the reducer have certain limits on the input rotating speed, the speed of the joint track is restricted as follows:
in the formulae (27) and (28),
seed of a plant
The angular velocity and the maximum value of the angular velocity of the joint are respectively;
and
the joint angular acceleration and the maximum angular acceleration are respectively;
the surgical robot joint is driven by a motor, the motor has certain limitation on the maximum output torque, and the output torque of the motor is constrained as follows through a dynamic model:
in the formula (29), θ (t),
And
respectively motor angle, angular velocity and angular acceleration, J
eqAnd B
eqRespectively equivalent inertia and equivalent damping of the joint, M is a reduction ratio coefficient, G (theta (t)) is joint connecting rod gravity, and tau (t) and tau
maxRespectively the output torque and the rated torque of the motor;
step 2.3.2, adopting time optimal and smoothness optimal multi-objective optimization, and obtaining the expression of the sequence quadratic programming constraint of the optimization model from formulas (26) to (29) as follows:
in the formulae (30) and (31), hi=ti+1-ti,kJIs the weight coefficient;
and optimizing the planned track through the sequential quadratic programming constraint of the optimization model.
The step 3 specifically comprises the following steps:
step 3.1, determining a master-slave mapping function;
and 3.2, determining an operation proportional coefficient, introducing the operation proportional coefficient into the master-slave mapping function in the step 3.1, and mapping the motion poses of the master hand and the slave hand by taking the actual track signal as input to realize the predictive control of the track of the master-slave surgical robot.
The step 3.1 is specifically as follows:
step 3.1.1, establishing a master hand and slave hand space coordinate system;
step 3.1.2, establishing a master-slave mapping function;
the pose of the main hand operation coordinate system E-XYZ and the display coordinate system D-XYZ is expressed as follows:
in the formula (32), the compound represented by the formula (32),
a transformation matrix representing the master hand operation coordinate system M-XYZ relative to the display coordinate system D-XYZ,
represents a principalA transformation matrix of the hand end coordinate system H-XYZ relative to the main hand operation table coordinate system M-XYZ,
a transformation matrix representing the slave operation end coordinate system S-XYZ relative to the slave hand end coordinate system E-XYZ,
a transformation matrix representing a slave hand coordinate system T-XYZ relative to a slave operation end coordinate system S-XYZ; therefore, the method comprises the following steps:
and (3) carrying out a Cartesian space increment mapping strategy on the formula (33) to obtain a master-slave mapping function:
in the formula (34), Ψ represents a control period,
is a matrix of positions from the hand(s),
is a matrix of the poses of the slave hand,
is a matrix of the position of the master hand,
is the pose matrix of the master hand.
The step 3.2 is specifically as follows:
setting λ as a running scaling factor in the master-slave mapping function, and λ only acts on position control, defining λ as:
in equation (35), σ is a position magnification factor that determines the size of the hand-made space, and can be obtained by:
in the formula (36), DMAnd HMDiameter and height of the working space of the master hand, respectively, DSAnd HSσ is determined from the hand-made space diameter and height, respectively, and from the hand-tip vibration amplitude:
in the formula (37), C is the amplitude of vibration from the end of the hand, CΔIs the minimum vibration amplitude of the slave hand in the step signal response;
by introducing operation ratio control in the formula (34), a master-slave pose mapping function can be obtained as follows:
and controlling the optimized track through a master-slave pose mapping function, and realizing the prediction control of the track of the master-slave surgical robot.
The invention has the beneficial effects that:
the invention relates to a master-slave mode surgical robot track prediction control method, which is characterized in that a least square support vector machine Kalman filtering algorithm is designed to filter the slight vibration of a surgical robot, so that the filtering time delay can be controlled within a real-time surgery acceptable range, and the filtering precision is ensured; the invention discloses a trajectory prediction control method of a master-slave surgical robot, which provides a Chebyshev pseudo-spectrum method and a sequence quadratic programming for performing trajectory planning prediction on the tail end of a slave mobile manipulator arm, introduces an operation control proportion, reduces the amplitude of vibration of the tail end of a slave hand and simultaneously achieves the aim of accurate operation; the invention relates to a master-slave mode surgical robot trajectory prediction control method, which is based on a Chebyshev pseudo-spectrum method, a sequence quadratic programming method and a Kalman filtering (Kalman filtering) algorithm to carry out slave hand trajectory prediction planning and filtering shake elimination; the Chebyshev pseudo-spectral method can convert the track optimization into a nonlinear programming problem, the discrete numerical solution of the Chebyshev pseudo-spectral method can be consistently close to the optimal solution of the original problem, and the Chebyshev pseudo-spectral method has quite high accuracy; kalman filtering is an optimal prediction algorithm, and can be combined with a state equation and input and output data of a system to perform optimal prediction, so that the terminal vibration filtering rate is improved, and the time delay in the operation process is overcome.
Detailed Description
The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.
The invention discloses a master-slave mode surgical robot track prediction control method, which is implemented according to the following steps as shown in figure 1:
step 1, designing a least square support vector machine Kalman vibration filtering algorithm, and filtering tremor signals of hands to obtain target track signals;
step 2, respectively carrying out trajectory planning on the target trajectory signal by a linear trajectory planning method and a Chebyshev pseudo-spectrum method to obtain a planned trajectory, and optimizing the planned trajectory by a quadratic planning method to obtain an actual trajectory signal;
and 3, mapping the motion poses of the master hand and the slave hand by taking the actual track signal as input through a master-slave pose mapping function, and realizing the prediction control of the track of the master-slave surgical robot.
The step 1 specifically comprises the following steps:
step 1.1, collecting the running track of a master hand, carrying out discretization calibration on the running track, and writing a Kalman filtering process into a state equation and a measurement process:
and (3) state process:
X(k)=AX(k-1)+w(k) (1),
the measurement process comprises the following steps:
Z(k)=HX(k)+v(k) (2),
in the formulas (1) and (2), x (k) is the state of the vibration signal in the main hand, the matrix a represents the state change, the vector z (k) is the signal measurement result, the matrix H represents the measurement change, the vector w (k) is the state noise, and the vector v (k) is the measurement noise, wherein w (k) and v (k) are gaussian white noises with the average value of 0, which are assumed to be independent of each other;
step 1.2, prediction
Predicting the value of the next time state according to the estimation value of the previous time state to become prior estimation, and predicting the error of the next time state to become prior error:
P(k|k-1)=AP(k-1|k-1)AT+Q (4),
in the formulas (3) and (4),
the state vector at time k is estimated from time k-1,
is the a posteriori estimated state vector at time k-1, P (k | k-1) is the covariance at time k estimated from time k-1, P (k-1| k-1) is the a posteriori estimated covariance at time k-1, Q is the process noise covariance;
step 1.3, update correction
Firstly, calculating Kalman gain, then calculating posterior estimation by using the prior estimation in the step 1.2, and simultaneously updating the prior error to the posterior error:
K(k)=P(k|k-1)HT[HP(k|k-1)HT+R]-1 (5),
P(k|k)=(I-K(k)H)P(k|k-1) (7),
in the formulae (5), (6) and (7),
predicting a state vector at the time k of updating according to the estimated state vector, predicting covariance at the time k of updating according to the estimated state vector by P (k | k), wherein I is an identity matrix, K (k) is Kalman gain at the time k, and R is measurement noise covariance;
step 1.4, establishing regression equations of R and Q by adopting a least square support vector machine regression algorithm, and processing process noise and measurement noise;
and step 1.5, substituting the regression equation of the process noise covariance Q and the measurement noise covariance R in the step 1.4 into the step 1.2 and the step 1.3 to obtain an improved Kalman vibration filtering algorithm, and filtering the tremor signal of the hand to obtain a target track signal.
The step 1.4 is specifically as follows:
step 1.4.1, establishing a least square support vector machine training set of
Wherein S
i∈R
nIs a mixture of the measured vibration signal and the ideal control signal, as an input vector, R
iE, R is the covariance of the measurement noise of the vibration signal in the mixed signal;
step 1.4.2, according to the least square support vector machine theory, converting the regression problem of the nonlinear function of R and Q into the regression problem of the linear function, mapping variables R and Q into a high-dimensional space F, and obtaining the nonlinear function:
R(k)=ωTφ(s)+b ω∈F,b∈R (8),
in the formula (8), phi(s) is a nonlinear mapping function, and omega and b are undetermined parameters;
step 1.4.3, the optimization problem of the least squares support vector machine is defined according to step 1.4.2:
Ri=ωTΦ(Si)+b+ei i=1,...,N (10),
in formulae (9) and (10), eiIs the relaxation variable at time i, C is a constant greater than 0, and equation (10) is the constraint of equation (9);
step 1.4.4, list lagrangian functions according to step 1.4.3:
in the formula (11), αiE, R, i 1, N, is a lagrange parameter;
step 1.4.5, for the general optimization problem with equality constraint in step 1.4.3, KKT gives the necessary condition for judging whether the solution value is the optimal solution, and calculates the partial derivative for all parameters of the lagrangian function listed in step 1.4.4;
step 1.4.6, set forth the system of linear equations for step 1.4.5:
in the formula (12), the reaction mixture is,
R=[R
1,...,R
N]
T,α=[α
1,...,α
N]
TΩ is the kernel matrix;
Ωij=Φ(si)TΦ(sj)=K(si,sj) i,j=1,...,N (13),
formula (A), (B) and13) in, K(s)i,sj) Is a kernel function, ΩijIs a kernel matrix of i rows and j columns;
step 1.4.7, solving the formula (12) to obtain the coefficient of the regression equation, namely obtaining the regression equation of the least square support vector machine for measuring the noise covariance R:
step 1.4.8, establishing a regression equation of the process noise covariance Q using steps 1.4.5 and 1.4.6, specifically:
in formulae (14) and (15) < alpha'iIs relative to aiLagrange parameter of (g), K(s)i,sj) Is relative to K(s)i,sj) B' is the pending parameter relative to b.
The step 2 specifically comprises the following steps:
step 2.1, carrying out track planning on the target track signal in a task space by a linear track planning method;
step 2.2, carrying out trajectory planning on the target trajectory signal in the joint space by a Chebyshev pseudo-spectrum method;
and 2.3, performing time-smoothness optimization on the tracks planned in the step 2.1 and the step 2.2 by a quadratic programming method to obtain an actual track signal.
The step 2.1 specifically comprises the following steps:
firstly, the position vector and the attitude vector of the mobile mechanical arm terminal point motion at the starting point and the terminal point of a task space are respectively represented as:
P
1=[x
1,y
1,z
1]
T、P
2=[x
2,y
2,z
2]
T、
the position vector and the attitude vector connecting the initial point and the target point are respectively:
P12=P2-P1=(x1-x2,y1-y2,z1-z2)T (16),
in the formulae (16) and (17), [ x, y, z]And
representing a position vector and a posture vector of a terminal point of a mobile mechanical arm under a task space coordinate system;
assuming that it takes time T from the initial value movement to the target value of the end point of the mobile manipulator, and then discretizing the position vector and the attitude vector, the position vector and the attitude vector of the end point of the mobile manipulator at the time T can be calculated:
in the formulae (18), (19), PtAnd RtFor the position vector and attitude vector at time t,
t denotes the time, te (t)
1,t
2) And v and ω denote slave mobile machines, respectivelyThe average linear velocity and the average angular velocity of the arm end point from the initial value to the target value.
The step 2.2 specifically comprises the following steps:
step 2.2.1, time intervals are changed
The Chebyshev pseudo-spectrum method is a track approximately approximating state and control based on interpolation polynomial, wherein Chebyshev-Gauss-Lobatto points are selected as nodes and defined in an interval of [ -1, 1]Introducing a new time variable tau epsilon-1, 1]The original time interval [ t ]0,tf]Conversion to [ -1, 1 [ ]]And t is expressed as:
step 2.2.2 calculation of discrete nodes
Chebyshev polynomial T selected from discrete nodes by Chebyshev pseudo-spectrum methodN(t)=cos(Ncos-1(t)) the extreme point, i.e. the CGL point;
step 2.2.3 interpolation approximation of state variables and control variables
Firstly, taking N +1 discrete points, and constructing a Lagrange interpolation polynomial as an approximate value of a continuous state and a control variable, wherein an approximate expression of the continuous state x (tau) and the control variable u (tau) is as follows:
in the formulae (21) and (22), xjIs the state at time j, ujIs the control variable at time j, wherejIs the lagrange interpolation basis function;
step 2.2.4, processing of dynamic constraints
The derivative of the formula (21) gives a continuous state at τ
kDerivative at point
The approximate expression is:
in the formula (23), DkjIs (N +1) × (N +1) differential matrix D row k, column j element;
obtained by formula (23)
Instead of the state variable derivative with respect to time and discretizing at the interpolation nodes, the differential equation constraints of the original optimal control problem can be transformed into algebraic constraints, i.e. for
k 0, 1.
In the formula (24), x (τ)k) Time continuous state, u (τ)k) Is a control variable, τkIs the CGL point, τfAnd τ0Is a new time variable;
step 2.2.5, approximate calculation of performance index integrals
The Clenshaw-Curtis numerical integration is adopted to carry out approximate calculation on the integral term in the optimized performance index, and for any continuous function p (t) in the range of [ -1, 1], the integral can be approximately calculated by adopting the accumulation of function values at N +1 CGL discrete points, namely
In the formula (25), ωk(k ═ 0, 1.., N) is the Clenshaw-Curtis integration weight.
The step 2.3 is specifically as follows:
step 2.3.1, establishing constraint conditions of optimization model
Firstly, in order to operate safety, a position of a joint of a slave manipulator arm is generally limited by a stopper, and in order to avoid exceeding a joint movement range, a joint track is subjected to position constraint, which is specifically expressed as follows:
θmin≤θ(t)≤θmax (26),
in the formula (26), θ (t) and θminAnd thetamaxThe minimum value and the maximum value of the joint angle and the joint rotatable angle are respectively;
because the motor and the reducer have certain limits on the input rotating speed, the speed of the joint track is restricted as follows:
in the formulae (27) and (28),
and
the angular velocity and the maximum value of the angular velocity of the joint are respectively;
and
the joint angular acceleration and the maximum angular acceleration are respectively;
the surgical robot joint is driven by a motor, the motor has certain limitation on the maximum output torque, and the output torque of the motor is constrained as follows through a dynamic model:
in the formula (29), θ (t),
And
respectively motor angle, angular velocity and angular acceleration, J
eqAnd B
eqRespectively equivalent inertia and equivalent damping of the joint, M is a reduction ratio coefficient, G (theta (t)) is joint connecting rod gravity, and tau (t) and tau
maxRespectively the output torque and the rated torque of the motor;
step 2.3.2, adopting time optimal and smoothness optimal multi-objective optimization, and obtaining the expression of the sequence quadratic programming constraint of the optimization model from formulas (26) to (29) as follows:
in the formulae (30) and (31), hi=ti+1-ti,kJIs the weight coefficient;
and optimizing the planned track through the sequential quadratic programming constraint of the optimization model.
The step 3 specifically comprises the following steps:
step 3.1, determining a master-slave mapping function;
and 3.2, determining an operation proportional coefficient, introducing the operation proportional coefficient into the master-slave mapping function in the step 3.1, and mapping the motion poses of the master hand and the slave hand by taking the actual track signal as input to realize the predictive control of the track of the master-slave surgical robot.
The step 3.1 is specifically as follows:
step 3.1.1, establishing a master hand and slave hand space coordinate system; as shown in fig. 2;
step 3.1.2, establishing a master-slave mapping function;
the pose of the main hand operation coordinate system E-XYZ and the display coordinate system D-XYZ is expressed as follows:
in the formula (32), the compound represented by the formula (32),
a transformation matrix representing the master hand operation coordinate system M-XYZ relative to the display coordinate system D-XYZ,
a transformation matrix representing the coordinate system H-XYZ of the end of the master hand relative to the coordinate system M-XYZ of the master hand operation table,
a transformation matrix representing the slave operation end coordinate system S-XYZ relative to the slave hand end coordinate system E-XYZ,
a transformation matrix representing a slave hand coordinate system T-XYZ relative to a slave operation end coordinate system S-XYZ; therefore, the method comprises the following steps:
and (3) carrying out a Cartesian space increment mapping strategy on the formula (33) to obtain a master-slave mapping function:
in the formula (34), Ψ represents a control period,
is a matrix of positions from the hand(s),
is a matrix of the poses of the slave hand,
is a matrix of the position of the master hand,
is the pose matrix of the master hand.
The step 3.2 is specifically as follows:
setting λ as a running scaling factor in the master-slave mapping function, and λ only acts on position control, defining λ as:
in equation (35), σ is a position magnification factor that determines the size of the hand-made space, and can be obtained by:
in the formula (36), DMAnd HMDiameter and height of the working space of the master hand, respectively, DSAnd HSσ is determined from the hand-made space diameter and height, respectively, and from the hand-tip vibration amplitude:
in the formula (37), C is the amplitude of vibration from the end of the hand, CΔIs the minimum vibration amplitude of the slave hand in the step signal response;
by introducing operation ratio control in the formula (34), a master-slave pose mapping function can be obtained as follows:
and controlling the optimized track through a master-slave pose mapping function, and realizing the prediction control of the track of the master-slave surgical robot.
As can be seen from fig. 3, the track signal before filtering becomes very unsmooth due to the inclusion of the hand tremor signal, which may cause the vibration of the surgical instrument from the end of the hand, affecting the precision and quality of the surgery; after the filtering is carried out by the least square support vector machine Kalman filter designed in the step 1, the tremble part of the mixed control signal can be effectively filtered, and the coincidence degree of the two signals is very high. The filtering algorithm designed by the invention has higher precision and no obvious time delay, and meets the requirement of real-time operation.