不确定环境下机器人螺丝刀的紧固力矩控制

Tightening Torque Control of Robotic Screw-Driver under Uncertain Environment

针对自动螺钉螺纹深度与紧固扭矩之间的关系,本文提出了一种带扰动观测器的伺服控制系统来估计螺丝的紧固扭矩,不使用扭矩传感器来测量紧固扭矩。本方法由紧固产生的反作用力矩可以转换成与控制器一起进入的等效电压。干扰观测器可以估测螺丝驱动器电机的状态变量和螺钉紧固期间的紧固扭矩,螺旋驱动器的角位移由状态反馈控制器控制,该控制器利用估计的干扰和状态产生反馈控制输入,并补偿反作用力矩。同时,为测试本文所提扭矩监测方法的有效性,模拟原型螺钉紧固平台进行仿真实验。仿真结果表明,当目标接近螺丝刀系统测试估计干扰时,扰动估计器可以快速响应外部扰动,精确控制旋转刀头的位移,并收敛到给定值,同时以非常短的响应时间快速估算紧固扭矩,证明了扰动观测器的有效性。该研究在现实生产中具有重要的实用价值。

During automatic screw tightening,most automatic screw tightening uses a torque sensor to monitor the tightening process,while the traditional method of automatic screw tightening is to limit the maximum tightening torque.However,recent research has shown that the relationship between tightening torque and thread depth can be used to control the tightening of the screws.Aiming at the relationship between the screw depth and the tightening torque of the automatic screw,this paper proposes a servo control system with a disturbance observer to estimate the tightening torque of the screw,and it does not use the torque sensor to measure the tightening torque.The reaction torque generated by the tightening of the method can be converted into an equivalent voltage that enters with the controller.The disturbance observer can estimate the state variables of the screw driver motor and the tightening torque during screw tightening.The angular displacement of the screw driver is controlled by a state feedback controller that uses the estimated disturbance and state to generate feedback control inputs and compensate for the reaction torque.At the same time,in order to test the effectiveness of the torque monitoring method proposed in this paper,the simulation prototype screw fastening platform is simulated.The simulation results show that when the target is close to the screwdriver system to test the estimated disturbance,the disturbance estimator can quickly respond to the external disturbance,accurately control the displacement of the rotating cutter head,converge to a given value,and quickly estimate the tightening torque with a very short response time.This proves the effectiveness of the disturbance observer.This research has important practical value in real production.