Stable and Intuitive Control of an Intelligent Assist Device

Area of Science:

• Robotics
• Control Systems
• Human-Robot Interaction

Background:

• Physical human-robot interaction (pHRI) demands high safety and dependability due to robot power.
• Ensuring robot stability is crucial for safety but insufficient for intuitive interaction.
• Cooperative motion must be intuitive and not hinder human performance.

Purpose of the Study:

• To design a variable admittance control law for stable and intuitive human-robot interaction.
• To guarantee robot stability during constrained motion.
• To enhance the intuitiveness of human-robot cooperation.

Main Methods:

• Developed a new variable admittance control law.
• Incorporated a stability observer for guaranteed stability.
• Utilized the time derivative of contact force to infer human intentions.
• Estimated interaction stiffness online using encoder and force sensor data.

Main Results:

• The control law ensures robot stability during constrained motion.
• The system provides intuitive human interaction.
• Online stiffness estimation method validated.
• User studies with a parallel robot and an industrial assist device confirmed effectiveness.

Conclusions:

• The proposed variable admittance control law enhances safety and intuitiveness in human-robot interaction.
• The stability observer and intention-inference mechanism are key contributions.
• The method is validated through practical experiments and user studies.