Robotics Planning 기초 벼락공부

이 글은 필자의 기본기 재확인을 위해 로보틱스 기초를 키워드 별로 정리한 글입니다. 

Basics

• Robot manipulator --multiple link and joints
  • Link: length (signed distance from joint i-1 to i), twist (angle from joint i-1 to i), force (linear motion) and torque (rotational motion)
  • Joint -description differ by joint types
• Planning: Given an initial state, goal and model, finding a sequence of actions to achieve a goal.
  • Planning focuses on improving computational-efficiency
  • It requires two different kinds of reasoning
    • 1. Task planning -task-level choices
    • 2. Motion planning -motion-level choices

What topics

1. Robot kinematics problem
   • How to describe position and orientation of the manipulator's end-effector relative to the base of the manipulator, given the function of the joint variables? 
     • Forward kinematics: Using frame, compute the end effector's trasform wrt the base
   • How to describe the joint variables, given the end-effector's position and orientation?
     • Inverse kinematics: Closed form solutions (Algebraic / Geometric), Numerical solutions (time consuming)
       • Multiple solutions may exist. Typically choose the one that is closest to the current joint angle/avoid collision.
2. Robot dynamics  problem 
   • When the joints move at certain force and torque, what the velocity of the end-effector is?; Predicting how a robot will move in responseto applied force
     • Forward dynamics 
   • When the robot motion/trajectory is given, what is the forces and torques required at the robot's joints?
     • Inverse dynamics; Most of the manipulators have joint angles at which Jacobian becomes singular, which makes the problem harder.
3. Task and motion planning
   • Sampling based motion planning --RRT
   • Task planning --PDDLStream

그외

1. How to compute DoF
2. moment of inertia?