An Improved Capacitive Sensor for Detecting the Micro-Clearance of Spherical Joints

Area of Science:

• Robotics and Mechanical Engineering
• Sensor Technology
• Mechatronics

Background:

• Spherical joints are crucial components in parallel manipulators and industrial robots due to their flexible and compact designs.
• Real-time detection of micro-clearance in spherical joints is essential for compensating motion errors and improving transmission accuracy in mechanical systems.

Purpose of the Study:

• To propose an improved capacitive sensor specifically designed for detecting the micro-clearance in spherical joints.
• To validate the sensor's performance through theoretical modeling and simulation.

Main Methods:

• The study details the proposed structure of the improved capacitive sensor.
• A mathematical model was developed to describe the relationship between differential capacitance and the eccentric micro-displacement of the ball within the joint.
• Simulations were conducted using Ansoft Maxwell to analyze the sensor's capacitance values under varying eccentric displacements.

Main Results:

• Simulated differential capacitance values closely matched theoretical predictions across different eccentric displacements, confirming the detection method's feasibility.
• The proposed capacitive sensor design demonstrated an ability to mitigate the capacitive fringe effect, leading to enhanced measurement accuracy.

Conclusions:

• The developed capacitive sensor is a feasible and effective solution for real-time micro-clearance detection in spherical joints.
• The sensor's design improvements contribute to higher measurement accuracy, which is vital for advanced robotic applications.