The shoulder complex is the most complex joint in human's four limbs and this poses a big challenge in the exoskeleton design to achieve a mechanism able to generate the desired motion while structurally complying with human anatomy. This chapter presents a novel design of an exoskeleton shoulder mechanism and its control. The new design is a hybrid mechanism that consists of two revolute joints connected together via a double parallelogram linkage (DPL). By virtue of a DPL, a remote center of rotation can be established for a spherical mechanism with threedegree-of-rotations. In the chapter, the working principle of the shoulder mechanism is described. The kinematics of the mechanism is analyzed. Mechanism design and exoskeleton control are also presented.

Chapter Contents:

• Abstract
• 5.1 Introduction
• 5.2 State-of-the-art in shoulder exoskeletons
• 5.3 Kinematics of spherical shoulder exoskeleton
• 5.3.1 Planar kinematics of the DPL
• 5.3.2 Kinematics of the shoulder mechanism
• 5.4 Shoulder mechanism design
• 5.5 Control strategies of exoskeleton shoulders
• 5.5.1 State-of-the-art exoskeleton control
• 5.5.2 Control algorithms
• 5.5.3 Trajectory-based control
• 5.5.4 Interaction-based control
• 5.6 Control of the shoulder mechanism
• 5.6.1 System description
• 5.7 Shoulder joint usability test
• 5.8 Conclusions
• References

Inspec keywords: biomechanics; dexterous manipulators; motion control; patient rehabilitation; couplings; medical robotics; manipulator kinematics; robot kinematics

Other keywords: mechanism design; complex joint; assistive applications; DPL; threedegree-of-rotations; desired motion; exoskeleton control; spherical mechanism; double parallelogram linkage; spherical shoulder exoskeletons; shoulder complex; exoskeleton design; revolute joints; human anatomy; big challenge; hybrid mechanism; exoskeleton shoulder mechanism; chapter

Subjects: Manipulators; Robotics; Spatial variables control; Biological and medical control systems; Robot and manipulator mechanics