Design and Development of a Test Rig for Ergonomic Evaluation of Pistol grip Power Tools

手动工具通常用于制造行业紧固紧固件。这些手动工具由于扭矩的积累，会在手上产生反作用力。这导致手在操作手工工具时用力。在这些重复性的工作中，反复拉伸手腕的肌腱会导致手腕的一些纤维被撕裂。这会导致肌腱发炎，进而导致肌腱炎。慢性肌腱疾病，如肌腱炎，是制造业失去工作和工人赔偿的主要原因。然而，操作参数（如操作人员位置、夹持力、拧紧算法和施加的扭矩）与产生的反扭矩之间的关系尚不清楚。本文提出了一种模型与实验相结合的方法来研究手枪握把手工具在不同操作位置拧紧紧固件时影响反力力矩的因素，以最大限度地减少手柄位移。用一个由弹簧和阻尼器组成的一阶线性模型来表示人手。20名经验丰富的手动工具操作员将在不同的位置上使用特制的手枪握把手动工具进行紧固任务。模型参数如弹簧刚度和阻尼系数将通过实验确定。一个定制的测试平台将被设计和建造来模拟手-工具的相互作用。该试验台将能够模拟实验中发现的各种弹簧和阻尼系数。该钻机将用于研究各种操作参数和非操作参数（如性别）对由反作用力引起的手柄位移的影响。然后确定将使每个操作位置的手柄位移最小的参数组合。利用研究结果，可以确定每个操作位置的最小手柄位移的参数。这将有助于工业合作伙伴设计任务和工作场所，从而减少重复性劳损，并遵循安全的工作习惯。

DC Hand tools are commonly used in manufacturing industries for tightening of fasteners. These hand tools will result in reaction torque on the hand due torque buildup. This results in forceful exertion of the hand operating the hand tools. Repeated stretching of tendons of the wrist during such repetitive tasks results in some of its fibers being torn. This results in inflammation of the tendon leading to tendinitis. Chronic tendon disorders, such as tendinitis, are major causes of lost work and workers' compensation in manufacturing industries. However, the correlation between operational parameters such as operator position, gripping force, tightening algorithm and torque applied to the reaction torque produced is unknown. We propose a combined modelling and experimental approach to study the factors that affect the reaction torque with the aim of minimizing the handle displacement when pistol grip hand tools are used to tighten fasteners in various operating positions. A first order linear model that consists of spring and dashpot will be used to represent the human hand. Twenty experienced hand tool operators will be conducting fastening tasks, in various positions, using instrumented pistol-grip hand tool on a specially made frame. The model parameters such as spring stiffness and damping coefficients will be determined through experiments A custom test rig will be designed and built to simulate the hand-tool interaction. The test rig would have capability to simulate various spring and damping coefficients that are experimentally found. The rig will be used to study the effect of various operational parameters and non-operational parameters such as gender on handle displacement due to reaction torque. The combination of parameters that would minimize the handle displacement in each operational position will then be determined. Using the results of the research, one can determine the parameters that would result in minimal handle displacement for each operational position. This will help the industrial partner to design the task and workplace so that repetitive strain injuries are reduced and safe working habits are followed.