Structure Design And Key Parts Development Of Industrial Cooperative Robots

With the development of robots and the improvement of market demand,man-machine cooperation and man-machine fusion have been paid more and more attention.It has become a hot research field at present.It has also become people's expectation of the future factory to work with robots.Aiming at the problems of poor safety,low adaptability,bulky,tedious installation,long debugging period,high technical requirements and poor cooperation ability of man-machine fusion,a kind of industrial cooperative robot with joint torque detection function and its key components are studied.The main tasks are as follows:(1)Configuration design of industrial cooperative robot:Firstly,the technical parameters of the industrial cooperative robot are given.The degree of freedom is 6,the payload is 4 kg,and the maximum radius of motion is 1140 mm.Then the configuration of the robot is analyzed.The arm is articulated and the wrist is RBR configuration.Finally,the transmission scheme is designed.Servo motor drive and hollow line are selected,and the transmission mode of"servo motor-reducer-joint torque sensor" is adopted.(2)Design of joint torque sensor,which is the key component of industrial cooperative robot.Firstly,a measuring principle of double differential capacitance is proposed to realize the detection of torque and improve the sensitivity,reliability and stability of the sensor.Secondly,in order to reduce the influence of force coupling effect on measurement accuracy,a decoupling structure of built-in cross roller bearing is proposed.Finally,the design indexes and parameters of each joint torque sensor are determined.The measurement ranges of the first to the fifth joint torque sensors are±450N·m,±500N·m,±200N·m,± 15N·m,±10N·m,respectively.The design,fabrication and assembly of the sensor are completed,and the calibration and decoupling validation experiments are carried out.The experimental results show that the sensor has the characteristics of high sensitivity,fast response and good anti-jamming ability;the designed decoupling structure can effectively reduce the influence of force coupling effect on the accuracy of measurement values;and the double differential structure can reduce the larger influence of interference force/torque on a single direction and improve the overall stability and reliability of sensors.(3)Structure design and machining of industrial cooperative robot:modular design method and considering the characteristics of each joint to complete the design of joint structure and arm and other connectors,and complete the whole machine virtual assembly,verify that the DH parameters meet the design requirements.The 7075 hard aluminum alloy is selected as the main structural material,and the parameters such as the total mass,the mass of each part,the center of gravity and the moment of inertia of the robot are obtained by SolidWorks three-dimensional software.The force of each joint is calculated and the selection of servo motor,reducer and conveyor belt is completed.Finally,the industrial collaboration robot is completed.(4)Impedance control simulation research and analysis:According to the characteristics that the industrial cooperative robot can obtain the joint torque in real time,preliminary impedance control algorithm and simulation research are carried out.In this paper,the kinematics and dynamics model of a two-degree-of-freedom robot is established,and an impedance control law is proposed based on the position control method.The impedance control model is established and simulated in the Simulink simulation environment.The following conclusions are drawn:?Increasing the stiffness parameter can make the robot show greater rigidity,and it will produce greater contact force when contacting with the environment,which is characterized by the increase of amplitude,period and stability time.?Reducing the damping parameter,it will increase the peak value of force,increase the number of shocks,and increase the stability time.?with increasing inertial parameters,the contact force,vibration period and stability time of robot and environment increase.This chapter lays a preliminary foundation for further research on force control,impedance control,force/position hybrid control and drag teaching based on this cooperative robot.