title: Design and control of a pneumatic musculoskeletal biped robot.
abstract: BACKGROUND
  Pneumatic artificial muscles are quite promising actuators for humanoid robots owing to their similar characteristics with human muscles. Moreover, biologically inspired musculoskeletal systems are particularly important for humanoid robots to perform versatile dynamic tasks.
  
  
  OBJECTIVE
  This study aims to develop a pneumatic musculoskeletal biped robot, and its controller, to realize human-like walking.
  
  
  METHODS
  According to the simplified musculoskeletal structure of human lower limbs, each leg of the biped robot is driven by nine muscles, including three pairs of monoarticular muscles which are arranged in the flexor-extensor form, as well as three biarticular muscles which span two joints. To lower cost, high-speed on/off solenoid valves rather than proportional valves are used to control the muscles. The joint trajectory tracking controller based on PID control method is designed to achieve the desired motion. Considering the complex characteristics of pneumatic artificial muscles, the control model is obtained through parameter identification experiments.
  
  
  RESULTS
  Preliminary experimental results demonstrate that the biped robot is able to walk with this control strategy.
  
  
  CONCLUSIONS
  The proposed musculoskeletal structure and control strategy are effective for the biped robot to achieve human-like walking.
authors.forename: Xizhe
authors.initials: X
authors.lastname: Zang
authors.forename: Yixiang
authors.initials: Y
authors.lastname: Liu
authors.forename: Xinyu
authors.initials: X
authors.lastname: Liu
authors.forename: Jie
authors.initials: J
authors.lastname: Zhao
mesh_terms: D004867:Equipment Design; D005684:Gait / Q000502:physiology; D018482:Muscle, Skeletal; D012371:Robotics; D016138:Walking
keywords: Biped robot; PID control; musculoskeletal structure; pneumatic artificial muscles