First, the basic working principle of robots, industrial robots widely used now belong to the first generation of robots, its basic working principle is teaching reproduction
Teaching is also called guiding, that is, the robot is guided by the user, and the actual task is operated step by step. The robot automatically remembers the position, posture, motion parameters, process parameters, etc. of each action of the teaching during the guiding process, and automatically generates A program that performs all operations in succession. After the teaching is completed, it is only necessary to give the robot a start command, and the robot will accurately follow the teaching action and complete all the operations step by step. This is teaching and reproduction.
(1) The movement of the robot arm. The robot arm is made up of several rigid rods and rotating or moving joints. It is an open-loop joint chain. One end of the open chain is fixed on the base and the other end is free. The end effector (such as a welding gun) is installed. When the robot is operated, the end effector of the front end of the robot arm must be in a position and posture corresponding to the workpiece to be processed, and these positions and postures are synthesized by the motion of several arm joints. of.
Therefore, in the robot motion control, it is necessary to know the relationship between the joint space of the arm and the position and posture of the end effector. This is the robot kinematics model. After the geometry of a robotic arm is determined, its kinematics model can be determined, which is the basis of robot motion control.
(2) Robot trajectory planning, the position of the robot manipulator from the position and attitude of the starting point to the position of the end point and the trajectory of the motion trajectory is called the path. The task of trajectory planning is to use a function to "interpolate" or "approach" a given path and generate a series of "control set points" along the time axis for controlling the robot movement. At present, the commonly used trajectory planning methods are spatial joint interpolation and Cartesian spatial programming.
(3) The control of the robot manipulator. When the dynamic motion equation of a robot manipulator is given, its control purpose is to maintain the dynamic response of the manipulator according to the predetermined performance requirements. However, since the inertial force, coupling reaction force and gravity load of the robot manipulator vary with the movement space, it is quite complicated and difficult to control it with high precision, high speed and high dynamic quality. At present, the control method adopted on industrial robots is to treat each joint of the manipulator as a single servo mechanism, which is to simplify a nonlinear, inter-joint-coupled variable load system into a linear uncoupled single system.