Research On Robust Control Strategy Of Powered Robot Wireless Power Transmission System

As a wearable medical rehabilitation device,the power-assisted robot can effectively help the disabled and the elderly gain the ability to walk.However,power supply is an important issue in assisting robotics technology.The existing power-assisted robots generally adopt cable power supply and battery power supply.On the one hand,this greatly restricts the working range of the robot.On the other hand,battery power supply causes the robot’s mass to become larger and its wearability is poor.Therefore,it is necessary to find a power supply method for the power-assisted robot that has a long endurance and flexible access to electric energy.However,when the robot is wirelessly charged,it will be interfered by the external environment.At the same time,the uncertainty of circuit hardware parameters and load jumps will affect the constant voltage output of the system.Therefore,in order to improve the robustness of the wireless power transmission system under the influence of various perturbation factors,it is necessary to perform closed-loop feedback control on the system.Based on wireless power transmission is a complex system with high-order,multi-parameter coupling and nonlinearity.This research designs a dual closed-loop output voltage feedback predictive control scheme based on the Luenberger disturbance observer(LDOB).The specific work is as follows:(1)Based on the working principle and research direction of wireless power transmission technology,this article briefly introduced the current research status of this technology at home and abroad.The four basic compensation and high-order compensation network topological structures of the original secondary side were analyzed,the mathematical model of the transmission unit is established,and the output power characteristic relationship of the system was derived.Through comparative analysis,this topic selects the LCL-S compensation structure that is more in line with the application scenarios of power-assisted robots.(2)It analyzed the control strategies and algorithms that were commonly used in wireless power transmission systems to improve the robustness.Because the traditional control method did not depend on the mathematical model of the specific control system.Therefore,this topic was led to design a predictive control algorithm for the wireless power transmission of a booster robot based on the Luenberger disturbance observation technology.(3)By modeling the topology of the LCL-S wireless power transmission system,a simplified model of extended wireless power transmission considering external disturbance and parameter mismatch was designed.The Luenberger observer was used to estimate the concentrated disturbances in the voltage and current loops separately,and designed a voltage controller and an improved predictive current controller.The output voltage was controlled by phase-shift modulation technology.Simulations were carried out under different working conditions,and compared with the traditional PI control method,the method had a good dynamic performance and parameter robustness.(4)The software and hardware design process of the system experiment platform was given.Among them,the hardware design mainly included the selection of the devices used in each module,the voltage/current sampling circuit and the conditioning protection circuit,etc.The software design included the logic flow of the system main program,ADC sampling module and ePWM interrupt service routine.The effectiveness of the control algorithm proposed in this paper was verified through experiments.