Novel Design of An Adjustable Constant Force Mechanism based on Cam and Spring

Keung, Godfrey; Chen, Chao

doi:10.1007/978-3-030-20131-9_146

Cited by 3 publications

(2 citation statements)

References 20 publications

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“…The impact of friction -more drastic as the target forces decrease -is often mitigated by rollers or sliders in these prototypes, yet fabrication considerations are not always fully investigated. Furthermore, in applications requiring fast disengaging as a safety feature, most designs fall short of providing this functionality (Keung and Chen 2019).…”

Section: Introductionmentioning

confidence: 99%

Design and Manufacturing Considerations of a Constant-Force Mechanism for Low Force Regimes

Popa¹,

Nowakowski²,

Lyder³

et al. 2022

Additive Manufacturing, Modeling Systems and 3D Prototyping

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The evolution of rapid prototyping and additive manufacturing technologies has triggered the return of constant-force mechanisms (CFMs) among trending research topics over the past decade. Moreover, CFMs represent functional, cost-efficient alternatives to more complicated force sensing setups widely used in precision manipulation systems. Delivering essentially constant force response over a prescribed displacement range solely due to their mechanical structure, CFMs lend themselves towards a damage-free interaction between actuators and their environment. Mechanical overload protection may be granted to robot end-effectors, with CFMs compensating for absent or costly force feedback. Targeting low forces such as those typically required in the biomedical sector has proven problematic due to the increased relative impact of friction during operation. This effort proposes a low force device which also acts as a safety release mechanism. Intended for oropharyngeal swabbing, the design employs standard mechanical components and 3D printed fixtures, thusly distinguishing itself from compliant mechanism counterparts, more sensitive to manufacturing tolerances.This paper encompasses the mathematical modeling of a curved surface which engages rollers, in turn connected to compression springs. The tailored use of bearings and contact surface materials reduces the impact of friction on the response. The formulation of the curve is also valid for forces far above the goal and may be used as a design guide for parabolic rolling. After numerically validating the mathematical model, a prototype was manufactured and tested. The repeated testing of the physical setup exhibited a maximum deviation of within +/- 13% from the 1 N target force. The findings are subsequently leveraged towards a case study of a hand-held throat swabbing device, manufactured and successfully tested within patient-acceptable swabbing force ranges.The presented procedure is helpful as a design guide for creating constant force mechanisms targeting low forces, manufactured from 3D printed parts and off-the-shelf mechanical components.

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Section: Introductionmentioning

confidence: 99%

Design and Manufacturing Considerations of a Constant-Force Mechanism for Low Force Regimes

Popa¹,

Nowakowski²,

Lyder³

et al. 2022

Additive Manufacturing, Modeling Systems and 3D Prototyping

View full text Add to dashboard Cite

show abstract

“…Constant force mechanisms exert forces with predetermined magnitude and direction, regardless of the mechanism configuration [1,2]. A common application of such systems in robotics is passive gravity balancing for manipulators.…”

Section: Introductionmentioning

confidence: 99%

Passive Gravity Balancing with a Self-Regulating Mechanism for Variable Payload

2021

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Gravity balancing techniques allow for the reduction of energy consumptions in robotic systems. With the appropriate arrangements, often including springs, the overall potential energy of a manipulator can be made configuration-independent, achieving an indifferent equilibrium for any position. On the other hand, such arrangements lose their effectiveness when some of the system parameters change, including the mass. This paper proposes a method to accommodate different payloads for a mechanism with a single degree-of-freedom (DOF). By means of an auxiliary mechanism including a slider, pulleys and a counterweight, the attachment point of a spring is automatically regulated so as to maintain the system in indifferent equilibrium regardless of the position, even when the overall mass of the system varies. Practical implications for the design of the mechanism are also discussed. Simulation results confirm the effectiveness of the proposed approach.

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Next Generation Autofocus and Optical Image Stabilization System for Camera Modules Using Magnetic Shape Memory Actuators

Gabdullin

Ahmad

2020

IEEE Access

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Currently, camera modules are used in a wide range of applications ranging from micropositioning actuator systems used in smartphones to larger modules used in stationary cameras, CCTV, and others. Modern camera modules are required to perform positioning functions to improve the stability and quality of captured images. These functions mainly include the autofocus (AF) and optical image stabilization (OIS) functions. Traditionally, separate actuators and sensors are used for AF and OIS, each contributing towards energy consumption, module size, and manufacturing costs. This is particularly disadvantageous in the case of smartphones owing to their inherent space and battery charge limitations. This paper presents a novel Magnetic Shape Memory (MSM) actuator system that combines the AF and OIS functions, which are performed using two actuators; thus, this system is a simple, compact, and costeffective solution to the drawbacks of conventional technology. Furthermore, the smart properties of MSM alloys reduce the energy consumption of these systems through the utilization of their inherent holding forces and the associated shape memory effect. The realization of AF and OIS functions is discussed and verified experimentally for the proposed actuator system using data obtained from a fabricated prototype.

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Novel Design of An Adjustable Constant Force Mechanism based on Cam and Spring

Cited by 3 publications

References 20 publications

Design and Manufacturing Considerations of a Constant-Force Mechanism for Low Force Regimes

Design and Manufacturing Considerations of a Constant-Force Mechanism for Low Force Regimes

Passive Gravity Balancing with a Self-Regulating Mechanism for Variable Payload

Next Generation Autofocus and Optical Image Stabilization System for Camera Modules Using Magnetic Shape Memory Actuators

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