An adjustable constant-force mechanism for adaptive end-effector operations
Journal
Journal of Mechanical Design
Journal Volume
134
Journal Issue
3
Start Page
031005
ISSN
10500472
Date Issued
2012
Author(s)
Chen, Yiho
Abstract
Force regulation is a challenging problem for robot end-effectors when interacting with an unknown environment. It often requires sophisticated sensors with computerized control. This paper presents an adjustable constant-force mechanism (ACFM) to passively regulate the contact force of a robot end-effector. The proposed ACFM combines the negative stiffness of a bistable mechanism and positive stiffness of a linear spring to generate a constant-force output. Through prestressing the linear spring, the constant-force magnitude can be adjusted to adapt to different working environments. The ACFM is a monolithic compliant mechanism that has no frictional wear and is capable of miniaturization. We propose a design formulation to find optimal mechanism configurations that produce the most constant-force. A resulting force to displacement curve and maximal stress curve can be easily manipulated to fit a different application requirement. Illustrated experiments show that an end-effector equipped with the ACFM can adapt to a surface of variable height, without additional motion programming. Since sensors and control effort are minimized, we expect this mechanism can provide a reliable alternative for robot end-effectors to interact friendly with an environment.
Subjects
Bistable Mechanism
Compliant Mechanism
Constant-force Mechanism
Force Regulation
Robot End-effector
Zero Stiffness
End Effectors
Mechanisms
Motion Planning
Robot Programming
Stiffness
Bistable Mechanisms
Computerized Controls
Constant Force
Constant Force Mechanisms
Contact Forces
Force Regulation
Linear Spring
Robot's End Effectors
Unknown Environments
Zero Stiffness
Compliant Mechanisms
SDGs
Publisher
American Society of Mechanical Engineers (ASME)
Type
journal article