Research Of Error Distribution Of Medical Manipulator Under Auxiliary Constraints And Control

The improvement of material life has increased people’s demand for medical services,especially for oral tongue cancer disease,the need for a device that can efficiently detect the tongue body,medical robotic arm can assist physicians in oral testing of patients,its control accuracy is high but the cost of use is high,how to improve the control accuracy of the general robot arm at a lower cost is the focus of relevant research scholars.Improving the control accuracy of the universal robot arm in a local workspace by constructing an auxiliary restraint mechanism is a feasible solution.Based on this as the background,this paper focuses on the influence of auxiliary constraints on the error of the robot arm and the control of the robot arm under the constraints,on the basis of calibrating and compensating the geometric error of the robot arm,establishes the kinematic model of the robot arm considering non-geometric errors,obtains the spatial distribution of the end repeatability error under different constraints,guides the addition of auxiliary constraints,and finally introduces fractional order admittance control in the robot arm under the auxiliary constraints,and completes the simulated tongue cancer detection experiment and the simulated parts assembly experiment.The main research contents of this paper are as follows:(1)In view of the problem that the working space and error change law of the tandem robot arm are not clear after the addition of auxiliary constraints,LM-DEH is first used to calibrate and compensate the geometric error of the robotic arm,and then the joint gap is measured by dot analysis;The joint model with non-geometric error is established by using the virtual connecting rod,and the repeatability error and its spatial distribution at the end of the robot arm under different auxiliary constraints are simulated,and the physical experiment is verified.Finally,an auxiliary constraint scheme is selected to reduce the end-of-line repeatability error in the local task space.(2)Aiming at the problem of the change of the control of the robot arm after the addition of auxiliary constraints,construct a Lagrange multiplier equation containing the position information of the constrained joints and ends,and search for the optimization to obtain the reverse solution of the robot arm that satisfies the constraints;Then the measurement scheme of the robotic arm with the auxiliary constraint and the interaction force with the patient is given;In view of the requirements of smooth control in the test,fractional admittance control is introduced to improve the response of the robot arm to external forces.(3)Using the 6 degrees of freedom tandem robotic arm x Arm as the experimental platform,the design of the robotic arm based on impedance spectroscopy technology under auxiliary constraints simulated tongue cancer detection experiments,respectively,the robotic arm single point and trajectory detection,and the analysis of experimental results,providing relevant theoretical and experimental basis for further automatic and accurate detection of tongue cancer margins;Then,the Jaco robotic arm under the auxiliary constraint is used to perform a simulated assembly experiment to verify the versatility of the auxiliary constraint to improve the accuracy.