This paper presents an automatic optimization method for compliant constant force mechanisms, which eliminates the need for time-consuming parameter tuning and complex model design in the conventional design process. The proposed optimization framework is based on the finite-element analysis (FEA) and multi-objective genetic algorithm (MOGA) methods and is designed in two steps: First, the preliminary mechanism design is carried out to roughly encompass the specified constant force objective; then, the preliminary model is optimized by applying a MOGA based on FEA results. The optimized model can achieve the desired performance automatically while achieving a larger constant force stroke, which is verified by performing FEA simulations and experimental studies. The experimental results demonstrate that the designed CFMs increase the constant force stroke by 16.3% while achieving the specified design accuracy compared to the preliminary prototype.

Precise control of the manipulating force within an appropriate range is crucial to prevent potential damage to the operating object. However, achieving accurate force control through force feedback is challenging in micro-scale applications. This study presents the design of a quasi-zero stiffness-compliant constant-force microgripper with adjustable force output. The parameters of the constant-force mechanism are designed using a model-based optimization method. By utilizing this mechanism, a compliant microgripper capable of providing adjustable constant-force output is developed to overcome the limitation of traditional grippers that offer only a single constant force. Finite element analysis is performed to simulate the behavior and verify the stability of the constant-force output. Furthermore, an experimental platform is constructed to validate the mechanical properties of the developed microgripper. The experimental results demonstrate that the automatically optimized structural parameters enable the microgripper to achieve the desired constant-force value of 2 N with an adjustable range of 0.15 N. These findings provide a further basis for the application and promotion of compliant constant-force structures.