Human‐in‐the‐loop Control Using Euler Angles

The main objective of the human‐in‐the‐loop (HITL) control is to generate specific tasks to combine human skills and robot properties, for example, co‐manipulation, haptic operation, and learning from demonstrations. This chapter discusses a novel method that avoids the inverse kinematics solution and the Jacobian matrix by using minimal representation of the Euler angles. The key idea of the method is to use a linearized version of the Euler angles to decouple the robot control and simplify the task‐joint space transformation. The chapter utilizes the following four types of robots to show how to use the linearized Euler angles for the HITL control: 2‐degrees of freedom (DOF) robot, 4‐DOF robot, 5‐DOF robot, and 6‐DOF robot. The proportional‐integral‐derivative control is also a model‐free controller whose performance is good, but its integral gain must be adjusted carefully to avoid bad transient performance. The classical and the model‐free admittance controllers are modified with the Euler angles approach.