Design and motion analysis of a coal mine robot with variable wheel diameter

Area of Science:

• Robotics
• Mechanical Engineering
• Mining Technology

Background:

• Coal mines present complex, unstructured environments challenging for traditional robots.
• Existing robots often lack the adaptability for varied terrains and obstacles found in mining operations.

Purpose of the Study:

• To design and validate a robot with a variable wheel diameter mechanism for improved obstacle crossing and terrain adaptability in coal mines.
• To enhance the flexibility and lightweight nature of robots for special detection tasks in mining.

Main Methods:

• Developed a variable wheel diameter mechanism using gears, connecting rods, and sliding rails.
• Established kinematic models for both single wheels and the whole vehicle.
• Utilized RecurDyn software for dynamic simulations of robot maneuvers and obstacle surmounting.
• Constructed a 3D-printed prototype for experimental validation.

Main Results:

• The robot's wheel diameter can vary from a minimum radius of 107 mm to a maximum of 158 mm.
• The prototype successfully surmounted obstacles up to 172 mm in height, a 60.7% increase compared to common wheel-type robots.
• The robot's centroid rose by 50 mm when wheels unfolded, with minimal centroid fluctuation (3.6 mm) at maximum radius.

Conclusions:

• The variable wheel diameter robot demonstrates superior obstacle-crossing and terrain adaptation capabilities for unstructured environments.
• The design offers significant advantages in flexibility and weight compared to tracked and legged robots.
• This innovation provides a new direction for developing intelligent detection robots for future coal mine applications.