Constraint Study for a Hand Exoskeleton: Human Hand Kinematics and Dynamics

Table 4

Intrafinger constraints for a circular grasp.

Thumb	Index	Middle	Ring	Little
No constraint	𝜃CMC𝑓/𝑒Index=𝜃CMC𝑓/𝑒Middle	𝜃CMC𝑓/𝑒Middle=(1/2)𝜃CMC𝑓/𝑒Ring	𝜃CMC𝑓/𝑒Ring=(2/3)𝜃CMC𝑓/𝑒Little	No constraint
𝜃TMC𝑓/𝑒=(11/10)𝜃MCP𝑓/𝑒	No constraint	𝜃MCP𝑎𝑏/𝑎𝑑Middle=(1/5)𝜃MCP𝑎𝑏/𝑎𝑑Index	𝜃MCP𝑎𝑏/𝑎𝑑Ring=(1/2)𝜃MCP𝑎𝑏/𝑎𝑑Little	No constraint
𝜃MCP𝑓/𝑒=(4/5)𝜃IP𝑓/𝑒	𝜃MCP𝑓/𝑒Index=(4/3)𝜃PIP𝑓/𝑒Index	𝜃MCP𝑓/𝑒Middle=(4/3)𝜃PIP𝑓/𝑒Middle	𝜃MCP𝑓/𝑒Ring=(4/3)𝜃PIP𝑓/𝑒Ring	𝜃MCP𝑓/𝑒Little=(4/3)𝜃PIP𝑓/𝑒Little
No constraint	𝜃PIP𝑓/𝑒Index=(3/2)𝜃DIP𝑓/𝑒Index	𝜃PIP𝑓/𝑒Middle=(3/2)𝜃DIP𝑓/𝑒Middle	𝜃PIP𝑓/𝑒Ring=(3/2)𝜃DIP𝑓/𝑒Ring	𝜃PIP𝑓/𝑒Little=(3/2)𝜃DIP𝑓/𝑒Little